Science.gov

Sample records for zooplankton grazing rates

  1. Micro-zooplankton grazing as a means of fecal bacteria removal in stormwater BMPs.

    PubMed

    Burtchett, Jade M; Mallin, Michael A; Cahoon, Lawrence B

    2017-06-01

    A priority for environmental managers is control of stormwater runoff pollution, especially fecal microbial pollution. This research was designed to determine if fecal bacterial grazing by micro-zooplankton is a significant control on fecal bacteria in aquatic best management practices (BMPs); if grazing differs between a wet detention pond and a constructed wetland; and if environmental factors enhance grazing. Both 3-day grazing tests and 24-h dilution assays were used to determine grazing differences between the two types of BMP. Micro-zooplankton grazing was a stronger bacteria removal mechanism in stormwater wetlands rich in aquatic vegetation compared to a standard wet detention pond, although grazing was important in detention ponds as well. Our experiments indicated that the majority of grazers that fed on fecal bacteria were <20 μm in size. Grazing rates were positively correlated with fecal coliform abundance and increased water temperatures. Enumeration of grazers demonstrated that protozoans were significantly more abundant among wetland vegetation than in open water, and open wetland waters contained more flagellates and dinoflagellates than open wet detention pond waters. Grazing on fecal bacteria in BMPs is enhanced by aquatic vegetation, and grazing in aquatic BMPs in warmer climates should be greater than in cooler climates.

  2. Multisensor sampling of pelagic ecosystem variables in a coastal environment to estimate zooplankton grazing impact

    NASA Astrophysics Data System (ADS)

    Sutton, Tracey; Hopkins, Thomas; Remsen, Andrew; Burghart, Scott

    2001-01-01

    Sampling was conducted on the west Florida continental shelf ecosystem modeling site to estimate zooplankton grazing impact on primary production. Samples were collected with the high-resolution sampler, a towed array bearing electronic and optical sensors operating in tandem with a paired net/bottle verification system. A close biological-physical coupling was observed, with three main plankton communities: 1. a high-density inshore community dominated by larvaceans coincident with a salinity gradient; 2. a low-density offshore community dominated by small calanoid copepods coincident with the warm mixed layer; and 3. a high-density offshore community dominated by small poecilostomatoid and cyclopoid copepods and ostracods coincident with cooler, sub-pycnocline oceanic water. Both high-density communities were associated with relatively turbid water. Applying available grazing rates from the literature to our abundance data, grazing pressure mirrored the above bio-physical pattern, with the offshore sub-pycnocline community contributing ˜65% of grazing pressure despite representing only 19% of the total volume of the transect. This suggests that grazing pressure is highly localized, emphasizing the importance of high-resolution sampling to better understand plankton dynamics. A comparison of our grazing rate estimates with primary production estimates suggests that mesozooplankton do not control the fate of phytoplankton over much of the area studied (<5% grazing of daily primary production), but "hot spots" (˜25-50% grazing) do occur which may have an effect on floral composition.

  3. Grazing experiments and model simulations of the role of zooplankton in Phaeocystis food webs

    NASA Astrophysics Data System (ADS)

    Verity, P. G.

    2000-08-01

    A combined empirical and modelling study was conducted to further examine the potential importance of grazing by zooplankton in pelagic food webs in which Phaeocystis is a significant or dominant component. Laboratory experiments were designed to measure ingestion of Phaeocystis and other potential prey items which co-occur with Phaeocystis. Grazers included copepods and ciliates, and prey included Phaeocystis colonies and solitary cells, diatoms, ciliates, bacteria, and detritus. These data were expressed in the model currency of nitrogen units, and fit to hyperbolic tangent equations which included minimum prey thresholds. These equations and literature data were used to constrain a food web model whose purpose was to investigate trophic interactions rather than to mimic actual events. Nevertheless, the model output was similar to the general pattern and magnitude of development of Phaeocystis-diatom communities in some environments where they occur, e.g. north Norwegian waters. The model included three forms of nitrogen, three phytoplankton groups, bacteria, two zooplankton groups, and detritus, with detailed flows between compartments. An important component of the model was inclusion of variable prey preferences for zooplankton. The experiments and model simulations suggest several salient conclusions. Phaeocystis globosa colonies were eaten by a medium-sized copepod species, but ingestion appeared to be strongly dependent upon a proper size match between grazer and prey. If not, colonies were eaten little if at all. Phaeocystis solitary cells were ingested rapidly by ciliate microzooplankton, in agreement with prior literature observations. In contrast, detritus was eaten comparatively slowly by both ciliates and copepods. Both types of zooplankton exhibited apparent minimum prey thresholds below which grazing did not occur or was inconsequential. Model simulations implied that transitions between life cycle stages of Phaeocystis may potentially be important

  4. Grazing by Zooplankton on Diazotrophs in the Amazon River Plume and Western Tropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Conroy, B.; Steinberg, D. K.; Song, B.; Foster, R.

    2016-02-01

    Organisms capable of fixing di-nitrogen (N2), known as diazotrophs, are important primary producers and a potentially significant source for new nitrogen entering the planktonic food web. However, limited evidence exists for zooplankton grazing on diazotrophs compared to other primary producers. In the western tropical North Atlantic Ocean (WTNA), the Amazon River plume creates a niche for symbiotic diatom-diazotroph associations (DDAs) which can form large blooms. In adjacent non-plume-influenced waters, the colonial cyanobacterium Trichodesmium is abundant. In order to reveal zooplankton-diazotroph grazing interactions and determine the fate of newly fixed nitrogen, gut contents of zooplankton captured in these two regions were compared based on quantitative PCR (qPCR) assay of nitrogenase genes (nifH), and their microbiomes compared using next generation sequencing (NGS) analysis of 16S rRNA genes. We sampled individual copepods from discrete depth intervals (0-25m and 25-50m) and in two size classes (0.5-1mm and 1-2mm) for analysis. A modified DNA extraction protocol was developed and 54 extracts were used as templates in nifH qPCR assays for the larger size fraction diazotrophs (>10µm): Trichodesmium, and Hemiaulus or Rhizosolenia (diatoms)-Richelia (diazotroph) associations. Copepod gut content nifH copies ranged from 1.6 to 13.6 copies individual-1 for the assay targeting the Hemiaulus-Richelia DDA and from 1.1 to 3.0 copies individual-1 for Trichodesmium. 16S NGS conducted on 35 extracts with an Ion Torrent PGM and mothur revealed that cyanobacteria sequences accounted for up to 20% of sequences per extract. Our results show that both DDAs and Trichodesmium are prey for zooplankton, and that new nitrogen moves through the food web via these grazing interactions. These interactions should be considered in future explorations of the global ocean nitrogen cycle.

  5. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... rental rate that is less or more than the grazing rental rate established by us. We will assist a tribe... under paragraph (a) of this section. (c) Indian landowners may give us written authority to grant... grazing rental rate set by us; or (2) Below the grazing rental rate set by us, subject to our approval...

  6. Zooplankton Grazing Effects on Particle Size Spectra under Different Seasonal Conditions

    NASA Astrophysics Data System (ADS)

    Stamieszkin, K.; Poulton, N.; Pershing, A. J.

    2016-02-01

    Oceanic particle size spectra can be used to explain and predict variability in carbon export efficiency, since larger particles are more likely to sink to depth than small particles. The distribution of biogenic particle size in the surface ocean is the result of many variables and processes, including nutrient availability, primary productivity, aggregation, remineralization, and grazing. We conducted a series of grazing experiments to test the hypothesis that mesozooplankton shift particle size spectra toward larger particles, via grazing and egestion of relatively large fecal pellets. These experiments were carried out over several months, and used natural communities of mesozooplankton and their microbial prey, collected offshore of the Damariscotta River in the Gulf of Maine. We analyzed the samples using Fluid Imaging Technologies' FlowCam®, a particle imaging system. With this equipment, we processed live samples, decreasing the likelihood of losing or damaging fragile particles, and thereby lessening sources of error in commonly used preservation and enumeration protocols. Our results show how the plankton size spectrum changes as the Gulf of Maine progresses through a seasonal cycle. We explore the relationship of grazing community size structure to its effect on the overall biogenic particle size spectrum. At some times of year, mesozooplankton grazing does not alter the particle size spectrum, while at others it significantly does, affecting the potential for biogenic flux. We also examine prey selectivity, and find that chain diatoms are the only prey group preferentially consumed. Otherwise, we find that complete mesozooplankton communities are "evolved" to fit their prey such that most prey groups are grazed evenly. We discuss a metabolic numerical model which could be used to universalize the relationships between whole gazer and whole microbial communities, with respect to effects on particle size spectra.

  7. Diversity-dependent evolutionary rates in early Palaeozoic zooplankton.

    PubMed

    Foote, Michael; Cooper, Roger A; Crampton, James S; Sadler, Peter M

    2018-02-28

    The extent to which biological diversity affects rates of diversification is central to understanding macroevolutionary dynamics, yet no consensus has emerged on the importance of diversity-dependence of evolutionary rates. Here, we analyse the species-level fossil record of early Palaeozoic graptoloids, documented with high temporal resolution, to test directly whether rates of diversification were influenced by levels of standing diversity within this major clade of marine zooplankton. To circumvent the statistical regression-to-the-mean artefact, whereby higher- and lower-than-average values of diversity tend to be followed by negative and positive diversification rates, we construct a non-parametric, empirically scaled, diversity-independent null model by randomizing the observed diversification rates with respect to time. Comparing observed correlations between diversity and diversification rate to those expected from this diversity-independent model, we find evidence for negative diversity-dependence, accounting for up to 12% of the variance in diversification rate, with maximal correlation at a temporal lag of approximately 1 Myr. Diversity-dependence persists throughout the Ordovician and Silurian, despite a major increase in the strength and frequency of extinction and speciation pulses in the Silurian. By contrast to some previous work, we find that diversity-dependence affects rates of speciation and extinction nearly equally on average, although subtle differences emerge when we compare the Ordovician and Silurian. © 2018 The Author(s).

  8. The use of mechanistic descriptions of algal growth and zooplankton grazing in an estuarine eutrophication model

    NASA Astrophysics Data System (ADS)

    Baird, M. E.; Walker, S. J.; Wallace, B. B.; Webster, I. T.; Parslow, J. S.

    2003-03-01

    A simple model of estuarine eutrophication is built on biomechanical (or mechanistic) descriptions of a number of the key ecological processes in estuaries. Mechanistically described processes include the nutrient uptake and light capture of planktonic and benthic autotrophs, and the encounter rates of planktonic predators and prey. Other more complex processes, such as sediment biogeochemistry, detrital processes and phosphate dynamics, are modelled using empirical descriptions from the Port Phillip Bay Environmental Study (PPBES) ecological model. A comparison is made between the mechanistically determined rates of ecological processes and the analogous empirically determined rates in the PPBES ecological model. The rates generally agree, with a few significant exceptions. Model simulations were run at a range of estuarine depths and nutrient loads, with outputs presented as the annually averaged biomass of autotrophs. The simulations followed a simple conceptual model of eutrophication, suggesting a simple biomechanical understanding of estuarine processes can provide a predictive tool for ecological processes in a wide range of estuarine ecosystems.

  9. Combined effects of zooplankton grazing and dispersal on the diversity and assembly mechanisms of bacterial metacommunities.

    PubMed

    Berga, Mercè; Östman, Örjan; Lindström, Eva S; Langenheder, Silke

    2015-07-01

    Effects of dispersal and the presence of predators on diversity, assembly and functioning of bacterial communities are well studied in isolation. In reality, however, dispersal and trophic interactions act simultaneously and can therefore have combined effects, which are poorly investigated. We performed an experiment with aquatic metacommunities consisting of three environmentally different patches and manipulated dispersal rates among them as well as the presence or absence of the keystone species Daphnia magna. Daphnia magna reduced both local and regional diversity, whereas dispersal increased local diversity but decreased beta-diversity having no net effect on regional diversity. Dispersal modified the assembly mechanisms of bacterial communities by increasing the degree of determinism. Additionally, the combination of the D. magna and dispersal increased the importance of deterministic processes, presumably because predator-tolerant taxa were spread in the metacommunity via dispersal. Moreover, the presence of D. magna affected community composition, increased community respiration rates but did not affect bacterial production or abundance, whereas dispersal slightly increased bacterial production. In conclusion, our study suggests that predation by a keystone species such as D. magna and dispersal additively influence bacterial diversity, assembly processes and ecosystem functioning. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  10. Phytoplankton Composition and Abundance in Restored Maltański Reservoir under the Influence of Physico-Chemical Variables and Zooplankton Grazing Pressure

    PubMed Central

    Kozak, Anna; Gołdyn, Ryszard; Dondajewska, Renata

    2015-01-01

    In this paper we present the effects of environmental factors and zooplankton food pressure on phytoplankton in the restored man-made Maltański Reservoir (MR). Two methods of restoration: biomanipulation and phosphorus inactivation have been applied in the reservoir. Nine taxonomical groups of phytoplankton represented in total by 183 taxa were stated there. The richest groups in respect of taxa number were green algae, cyanobacteria and diatoms. The diatoms, cryptophytes, chrysophytes, cyanobacteria, green algae and euglenophytes dominated in terms of abundance and/or biomass. There were significant changes among environmental parameters resulting from restoration measures which influenced the phytoplankton populations in the reservoir. These measures led to a decrease of phosphorus concentration due to its chemical inactivation and enhanced zooplankton grazing as a result of planktivorous fish stocking. The aim of the study is to analyse the reaction of phytoplankton to the restoration measures and, most importantly, to determine the extent to which the qualitative and quantitative composition of phytoplankton depends on variables changing under the influence of restoration in comparison with other environmental variables. We stated that application of restoration methods did cause significant changes in phytoplankton community structure. The abundance of most phytoplankton taxa was negatively correlated with large zooplankton filter feeders, and positively with zooplankton predators and concentrations of ammonium nitrogen and partly of phosphates. However, restoration was insufficient in the case of decreasing phytoplankton abundance. The effects of restoration treatments were of less importance for the abundance of phytoplankton than parameters that were independent of the restoration. This was due to the continuous inflow of large loads of nutrients from the area of the river catchment. PMID:25906352

  11. Phytoplankton Composition and Abundance in Restored Maltański Reservoir under the Influence of Physico-Chemical Variables and Zooplankton Grazing Pressure.

    PubMed

    Kozak, Anna; Gołdyn, Ryszard; Dondajewska, Renata

    2015-01-01

    In this paper we present the effects of environmental factors and zooplankton food pressure on phytoplankton in the restored man-made Maltański Reservoir (MR). Two methods of restoration: biomanipulation and phosphorus inactivation have been applied in the reservoir. Nine taxonomical groups of phytoplankton represented in total by 183 taxa were stated there. The richest groups in respect of taxa number were green algae, cyanobacteria and diatoms. The diatoms, cryptophytes, chrysophytes, cyanobacteria, green algae and euglenophytes dominated in terms of abundance and/or biomass. There were significant changes among environmental parameters resulting from restoration measures which influenced the phytoplankton populations in the reservoir. These measures led to a decrease of phosphorus concentration due to its chemical inactivation and enhanced zooplankton grazing as a result of planktivorous fish stocking. The aim of the study is to analyse the reaction of phytoplankton to the restoration measures and, most importantly, to determine the extent to which the qualitative and quantitative composition of phytoplankton depends on variables changing under the influence of restoration in comparison with other environmental variables. We stated that application of restoration methods did cause significant changes in phytoplankton community structure. The abundance of most phytoplankton taxa was negatively correlated with large zooplankton filter feeders, and positively with zooplankton predators and concentrations of ammonium nitrogen and partly of phosphates. However, restoration was insufficient in the case of decreasing phytoplankton abundance. The effects of restoration treatments were of less importance for the abundance of phytoplankton than parameters that were independent of the restoration. This was due to the continuous inflow of large loads of nutrients from the area of the river catchment.

  12. Zooplankton Community Grazing Impact on a Toxic Bloom of Alexandrium fundyense in the Nauset Marsh System, Cape Cod, Massachusetts, USA

    PubMed Central

    Petitpas, Christian M.; Turner, Jefferson T.; Keafer, Bruce A.; McGillicuddy, Dennis J.; Anderson, Donald M.

    2016-01-01

    Embayments and salt ponds along the coast of Massachusetts can host localized blooms of the toxic dinoflagellate Alexandrium fundyense. One such system, exhibiting a long history of toxicity and annual closures of shellfish beds, is the Nauset Marsh System (NMS) on Cape Cod. In order measure net growth rates of natural A. fundyense populations in the NMS during spring 2012, incubation experiments were conducted on seawater samples from two salt ponds within the NMS (Salt Pond and Mill Pond). Seawater samples containing natural populations of grazers and A. fundyense were incubated at ambient temperatures. Concentrations of A. fundyense after incubations were compared to initial abundances to determine net increases from population growth, or decreases presumed to be primarily due to grazing losses. Abundances of both microzooplankton (ciliates, rotifers, copepod nauplii and heterotrophic dinoflagellates) and mesozooplankton (copepodites and adult copepods, marine cladocerans, and meroplankton) grazers were also determined. This study documented net growth rates that were highly variable throughout the bloom, calculated from weekly bloom cell counts from the start of sampling to bloom peak in both ponds (Mill Pond range = 0.12 – 0.46 d−1; Salt Pond range = −0.02 – 0.44 d−1). Microzooplankton grazers that were observed with ingested A. fundyense cells included polychaete larvae, rotifers, tintinnids, and heterotrophic dinoflagellates of the genera Polykrikos and Gymnodinium. Significant A. fundyense net growth was observed in two incubation experiments, and only a single experiment exhibited significant population losses. For the majority of experiments, due to high variability in data, net changes in A. fundyense abundance were not significant after the 24-hr incubations. However, experimental net growth rates through bloom peak were not statistically distinguishable from estimated long-term average net growth rates of natural populations in each pond

  13. Optimising stocking rate and grazing management to enhance environmental and production outcomes for native temperate grasslands

    NASA Astrophysics Data System (ADS)

    Badgery, Warwick; Zhang, Yingjun; Huang, Ding; Broadfoot, Kim; Kemp, David; Mitchell, David

    2015-04-01

    Stocking rate and grazing management can be altered to enhance the sustainable production of grasslands but the relative influence of each has not often been determined for native temperate grasslands. Grazing management can range from seasonal rests through to intensive rotational grazing involving >30 paddocks. In large scale grazing, it can be difficult to segregate the influence of grazing pressure from the timing of utilisation. Moreover, relative grazing pressure can change between years as seasonal conditions influence grassland production compared to the relative constant requirements of animals. This paper reports on two studies in temperate native grasslands of northern China and south eastern Australia that examined stocking rate and regionally relevant grazing management strategies. In China, the grazing experiment involved combinations of a rest, moderate or heavy grazing pressure of sheep in spring, then moderate or heavy grazing in summer and autumn. Moderate grazing pressure at 50% of the current district average, resulted in the better balance between maintaining productive and diverse grasslands, a profitable livestock system, and mitigation of greenhouse gases through increased soil carbon, methane uptake by the soil, and efficient methane emissions per unit of weight gain. Spring rests best maintained a desirable grassland composition, but had few other benefits and reduced livestock productivity due to lower feed quality from grazing later in the season. In Australia, the grazing experiment compared continuous grazing to flexible 4- and 20-paddock rotational grazing systems with sheep. Stocking rates were adjusted between systems biannually based on the average herbage mass of the grassland. No treatment degraded the perennial pasture composition, but ground cover was maintained at higher levels in the 20-paddock system even though this treatment had a higher stocking rate. Overall there was little difference in livestock production (e.g. kg

  14. Increases of Chamber Height and Base Diameter Have Contrasting Effects on Grazing Rate of Two Cladoceran Species: Implications for Microcosm Studies.

    PubMed

    Pan, Ying; Zhang, Yunshu; Peng, Yan; Zhao, Qinghua; Sun, Shucun

    2015-01-01

    Aquatic microcosm studies often increase either chamber height or base diameter (to increase water volume) to test spatial ecology theories such as "scale" effects on ecological processes, but it is unclear whether the increase of chamber height or base diameter have the same effect on the processes, i.e., whether the effect of the shape of three-dimensional spaces is significant. We orthogonally manipulated chamber height and base diameter and determined swimming activity, average swimming velocity and grazing rates of the cladocerans Daphnia magna and Moina micrura (on two algae Scenedesmus quadricauda and Chlorella vulgaris; leading to four aquatic algae-cladoceran systems in total) under different microcosm conditions. Across all the four aquatic systems, increasing chamber height at a given base diameter significantly decreased the duration and velocity of horizontal swimming, and it tended to increase the duration but decrease the velocity of vertical swimming. These collectively led to decreases in both average swimming velocity and grazing rate of the cladocerans in the tall chambers (at a given base diameter), in accordance with the positive relationship between average swimming velocity and grazing rate. In contrast, an increase of base diameter at a given chamber height showed contrasting effects on the above parameters. Consistently, at a given chamber volume increasing ratio of chamber height to base diameter decreased the average swimming velocity and grazing rate across all the aquatic systems. In general, increasing chamber depth and base diameter may exert contrasting effects on zooplankton behavior and thus phytoplankton-zooplankton interactions. We suggest that spatial shape plays an important role in determining ecological process and thus should be considered in a theoretical framework of spatial ecology and also the physical setting of aquatic microcosm experiments.

  15. Increases of Chamber Height and Base Diameter Have Contrasting Effects on Grazing Rate of Two Cladoceran Species: Implications for Microcosm Studies

    PubMed Central

    Pan, Ying; Zhang, Yunshu; Peng, Yan; Zhao, Qinghua; Sun, Shucun

    2015-01-01

    Aquatic microcosm studies often increase either chamber height or base diameter (to increase water volume) to test spatial ecology theories such as “scale” effects on ecological processes, but it is unclear whether the increase of chamber height or base diameter have the same effect on the processes, i.e., whether the effect of the shape of three-dimensional spaces is significant. We orthogonally manipulated chamber height and base diameter and determined swimming activity, average swimming velocity and grazing rates of the cladocerans Daphnia magna and Moina micrura (on two algae Scenedesmus quadricauda and Chlorella vulgaris; leading to four aquatic algae-cladoceran systems in total) under different microcosm conditions. Across all the four aquatic systems, increasing chamber height at a given base diameter significantly decreased the duration and velocity of horizontal swimming, and it tended to increase the duration but decrease the velocity of vertical swimming. These collectively led to decreases in both average swimming velocity and grazing rate of the cladocerans in the tall chambers (at a given base diameter), in accordance with the positive relationship between average swimming velocity and grazing rate. In contrast, an increase of base diameter at a given chamber height showed contrasting effects on the above parameters. Consistently, at a given chamber volume increasing ratio of chamber height to base diameter decreased the average swimming velocity and grazing rate across all the aquatic systems. In general, increasing chamber depth and base diameter may exert contrasting effects on zooplankton behavior and thus phytoplankton-zooplankton interactions. We suggest that spatial shape plays an important role in determining ecological process and thus should be considered in a theoretical framework of spatial ecology and also the physical setting of aquatic microcosm experiments. PMID:26273836

  16. Microplastics Alter the Properties and Sinking Rates of Zooplankton Faecal Pellets.

    PubMed

    Cole, Matthew; Lindeque, Penelope K; Fileman, Elaine; Clark, James; Lewis, Ceri; Halsband, Claudia; Galloway, Tamara S

    2016-03-15

    Plastic debris is a widespread contaminant, prevalent in aquatic ecosystems across the globe. Zooplankton readily ingest microscopic plastic (microplastic, < 1 mm), which are later egested within their faecal pellets. These pellets are a source of food for marine organisms, and contribute to the oceanic vertical flux of particulate organic matter as part of the biological pump. The effects of microplastics on faecal pellet properties are currently unknown. Here we test the hypotheses that (1) faecal pellets are a vector for transport of microplastics, (2) polystyrene microplastics can alter the properties and sinking rates of zooplankton egests and, (3) faecal pellets can facilitate the transfer of plastics to coprophagous biota. Following exposure to 20.6 μm polystyrene microplastics (1000 microplastics mL(-1)) and natural prey (∼1650 algae mL(-1)) the copepod Calanus helgolandicus egested faecal pellets with significantly (P < 0.001) reduced densities, a 2.25-fold reduction in sinking rates, and a higher propensity for fragmentation. We further show that microplastics, encapsulated within egests of the copepod Centropages typicus, could be transferred to C. helgolandicus via coprophagy. Our results support the proposal that sinking faecal matter represents a mechanism by which floating plastics can be vertically transported away from surface waters.

  17. Strong Spatial Influence on Colonization Rates in a Pioneer Zooplankton Metacommunity

    PubMed Central

    Frisch, Dagmar; Cottenie, Karl; Badosa, Anna; Green, Andy J.

    2012-01-01

    The magnitude of community-wide dispersal is central to metacommunity models, yet dispersal is notoriously difficult to quantify in passive and cryptic dispersers such as many freshwater invertebrates. By overcoming the problem of quantifying dispersal rates, colonization rates into new habitats can provide a useful estimate of the magnitude of effective dispersal. Here we study the influence of spatial and local processes on colonization rates into new ponds that indicate differential dispersal limitation of major zooplankton taxa, with important implications for metacommunity dynamics. We identify regional and local factors that affect zooplankton colonization rates and spatial patterns in a large-scale experimental system. Our study differs from others in the unique setup of the experimental pond area by which we were able to test spatial and environmental variables at a large spatial scale. We quantified colonization rates separately for the Copepoda, Cladocera and Rotifera from samples collected over a period of 21 months in 48 newly constructed temporary ponds of 0.18–2.95 ha distributed in a restored wetland area of 2,700 ha in Doñana National Park, Southern Spain. Species richness upon initial sampling of new ponds was about one third of that in reference ponds, although the rate of detection of new species from thereon were not significantly different, probably owing to high turnover in the dynamic, temporary reference ponds. Environmental heterogeneity had no detectable effect on colonization rates in new ponds. In contrast, connectivity, space (based on latitude and longitude) and surface area were key determinants of colonization rates for copepods and cladocerans. This suggests dispersal limitation in cladocerans and copepods, but not in rotifers, possibly due to differences in propagule size and abundance. PMID:22792241

  18. Strong spatial influence on colonization rates in a pioneer zooplankton metacommunity.

    PubMed

    Frisch, Dagmar; Cottenie, Karl; Badosa, Anna; Green, Andy J

    2012-01-01

    The magnitude of community-wide dispersal is central to metacommunity models, yet dispersal is notoriously difficult to quantify in passive and cryptic dispersers such as many freshwater invertebrates. By overcoming the problem of quantifying dispersal rates, colonization rates into new habitats can provide a useful estimate of the magnitude of effective dispersal. Here we study the influence of spatial and local processes on colonization rates into new ponds that indicate differential dispersal limitation of major zooplankton taxa, with important implications for metacommunity dynamics. We identify regional and local factors that affect zooplankton colonization rates and spatial patterns in a large-scale experimental system. Our study differs from others in the unique setup of the experimental pond area by which we were able to test spatial and environmental variables at a large spatial scale. We quantified colonization rates separately for the Copepoda, Cladocera and Rotifera from samples collected over a period of 21 months in 48 newly constructed temporary ponds of 0.18-2.95 ha distributed in a restored wetland area of 2,700 ha in Doñana National Park, Southern Spain. Species richness upon initial sampling of new ponds was about one third of that in reference ponds, although the rate of detection of new species from thereon were not significantly different, probably owing to high turnover in the dynamic, temporary reference ponds. Environmental heterogeneity had no detectable effect on colonization rates in new ponds. In contrast, connectivity, space (based on latitude and longitude) and surface area were key determinants of colonization rates for copepods and cladocerans. This suggests dispersal limitation in cladocerans and copepods, but not in rotifers, possibly due to differences in propagule size and abundance.

  19. Phytoplankton growth balanced by clam and zooplankton grazing and net transport into the low-salinity zone of the San Francisco Estuary

    USGS Publications Warehouse

    Kimmerer, Wim J.; Thompson, Janet K.

    2014-01-01

    We estimated the influence of planktonic and benthic grazing on phytoplankton in the strongly tidal, river-dominated northern San Francisco Estuary using data from an intensive study of the low salinity foodweb in 2006–2008 supplemented with long-term monitoring data. A drop in chlorophyll concentration in 1987 had previously been linked to grazing by the introduced clam Potamocorbula amurensis, but numerous changes in the estuary may be linked to the continued low chlorophyll. We asked whether phytoplankton continued to be suppressed by grazing and what proportion of the grazing was by benthic bivalves. A mass balance of phytoplankton biomass included estimates of primary production and grazing by microzooplankton, mesozooplankton, and clams. Grazing persistently exceeded net phytoplankton growth especially for larger cells, and grazing by microzooplankton often exceeded that by clams. A subsidy of phytoplankton from other regions roughly balanced the excess of grazing over growth. Thus, the influence of bivalve grazing on phytoplankton biomass can be understood only in the context of limits on phytoplankton growth, total grazing, and transport.

  20. Indicators: Zooplankton

    EPA Pesticide Factsheets

    Zooplankton are small, free-floating aquatic microorganisms including crustaceans, rotifers, open water insect larvae, and aquatic mites. The zooplankton community is composed of both primary consumers and secondary consumers.

  1. Zooplankton in the Arctic outflow

    NASA Astrophysics Data System (ADS)

    Soloviev, K. A.; Dritz, A. V.; Nikishina, A. B.

    2009-04-01

    content were measured in dominant species to investigate effect of Chl a concentration and phytoplankton composition on ingestion rate. Egg production experiments were carried out under different food conditions. Rare deep water zooplankton species were also investigated to increase our knowledge in the Arctic biodiversity. Copepods Calanus finmarchicus is known as a marker of the Atlantic water mass, Calanus glacialis and Calanus hyperboreus, vice versa, are the coldwater Arctic species. In our study we investigated three Calanus species distribution and analyzed their ecological status. Changes in zooplankton composition results in the alteration of energy transfer within the pelagic food web ("cold" and "warm" scenarios) with potential consequences for growth and survival of seabirds Little Auk (Alle alle) and Black-legged kittiwake (Rissa tridactyla). We discuss the advection effect on the zooplankton community, compare the population development phases with phytoplankton bloom phases (match-mismatch), estimate grazing impact on phytoplankton community and consider different life strategies for the three different Calanus species.

  2. Effects of livestock species and stocking density on accretion rates in grazed salt marshes

    NASA Astrophysics Data System (ADS)

    Nolte, Stefanie; Esselink, Peter; Bakker, Jan P.; Smit, Christian

    2015-01-01

    Coastal ecosystems, such as salt marshes, are threatened by accelerated sea-level rise (SLR). Salt marshes deliver valuable ecosystem services such as coastal protection and the provision of habitat for a unique flora and fauna. Whether salt marshes in the Wadden Sea area are able to survive accelerated SLR depends on sufficient deposition of sediments which add to vertical marsh accretion. Accretion rate is influenced by a number of factors, and livestock grazing was recently included. Livestock grazing is assumed to reduce accretion rates in two ways: (a) directly by increasing soil compaction through trampling, and (b) indirectly by affecting the vegetation structure, which may lower the sediment deposition. For four years, we studied the impact of two livestock species (horse and cattle) at two stocking densities (0.5 and 1.0 animal ha-1) on accretion in a large-scale grazing experiment using sedimentation plates. We found lower cumulative accretion rates in high stocking densities, probably because more animals cause more compaction and create a lower canopy. Furthermore, a trend towards lower accretion rates in horse-compared to cattle-grazed treatments was found, most likely because (1) horses are more active and thus cause more compaction, and (2) herbage intake by horses is higher than by cattle, which causes a higher biomass removal and shorter canopy. During summer periods, negative accretion rates were found. When the grazing and non-grazing seasons were separated, the impact of grazing differed among years. In summer, we only found an effect of different treatments if soil moisture (precipitation) was relatively low. In winter, a sufficiently high inundation frequency was necessary to create differences between grazing treatments. We conclude that stocking densities, and to a certain extent also livestock species, affect accretion rates in salt marshes. Both stocking densities and livestock species should thus be taken into account in management

  3. Managing broiler litter application rate and grazing to decrease watershed runoff losses.

    PubMed

    Sistani, K R; Brink, G E; Oldham, J L

    2008-01-01

    Pasture management and broiler litter application rate are critical factors influencing the magnitude of nutrients being transported by runoff from fields. We investigated the impact of pasture management and broiler litter application rate on nutrient runoff from bermudagrass (Cynodon dactylon) pastures. The experiment was conducted on a Ruston fine sandy loam with a factorial arrangement on 21 large paddocks. Runoff water was collected from natural rainfall events from 2001 to 2003. Runoff water and soil samples were analyzed for nutrients and sediments. Runoff was generally greater (29%) from grazed than hayed pastures regardless of the litter application rate. There was greater inorganic N in the runoff from grazed paddocks when litter rate was based on N rather than P. The mean total P loss per runoff event for all treatments ranged from 7 to 45 g ha(-1) and the grazed treatment with litter applied on N basis had the greatest total P loss. Total dissolved P was the dominant P fraction in the runoff, ranging from 85% to 93% of the total P. The soluble reactive P was greater for treatments with litter applied on N basis regardless of pasture management. Runoff total sediments were greater for N-based litter application compared to those which received litter on P basis. Our results indicate that litter may be applied on N basis if the pasture is hayed and the soil P is low. In contrast, litter rates should be based on a P-basis if pasture is grazed.

  4. Reduced grazing rates in Daphnia pulex caused by contaminants: implications for trophic cascades.

    PubMed

    Bengtsson, Göran; Hansson, Lars-Anders; Montenegro, Katia

    2004-11-01

    Ecotoxicological endpoints based on behavioral traits (e.g., predator avoidance, feeding, and locomotion) may be more sensitive and give more insights into patterns of sublethal toxicity than survivorship tests. In this study, the density-dependent grazing rate of Daphnia pulex pre-exposed to p,p'-dichlorodiphenyldichloroethylene (DDE) (insecticide metabolite) and glyphosate (herbicide), via water or a vector, Scenedesmus spp., was assayed in laboratory experiments. The phytoplankton biomass was estimated from the chlorophyll content, and the pesticide uptake and turnover pattern in Daphnia and Scenedesmus were determined from parallel experiments with a radiolabeled source. Scenedesmus spp. relative net growth rate was inversely and linearly related to the density of the grazer. Daphnia pulex exhibited significant reductions in grazing rate: 30% for those pre-exposed to p,p'-DDE via water and 40% for D. pulex pre-exposed to glyphosate via Scenedesmus spp. Through the process of trophic cascading, this impaired grazing allowed Scenedesmus spp. to grow at higher rates, 70 and 60%, respectively. The reduced grazing efficiencies were associated with the treatments that gave the highest body burden of p,p'-DDE (70 microg/g dry wt) and the lowest of glyphosate (13 mg/g dry wt). The pattern of results suggests a toxic effect of p,p'-DDE on D. pulex and a growth enhancement of Scenedesmus spp. in response to nitrogen and phosphorus in glyphosate excreted by D. pulex.

  5. Influence of stocking rate and steroidal implants on growth rate of steers grazing toxic tall fescue and subsequent physiological responses.

    PubMed

    Aiken, G E; Looper, M L; Tabler, S F; Brauer, D K; Strickland, J R; Schrick, F N

    2006-06-01

    An 84-d grazing experiment was conducted in 2 growing seasons to evaluate interactions of stocking rate and steroidal implants with BW gain and symptoms of toxicosis in yearling steers grazing endemic endophyte-infected (E+) tall fescue (Festuca arundinacea Schreb.). A 4 x 2 factoral design was used to evaluate 4 stocking rates (3.0, 4.0, 5.0, and 6.0 steers/ ha) with or without steroidal implants (200 mg of progesterone + 20 mg of estradiol benzoate). Treatment combinations were randomly assigned to eight 1-ha pastures of E+ Kentucky-31 tall fescue (i.e., treatments were not replicated). Treatment effects were analyzed for ADG, total BW gain per hectare, forage availability, and hair coat ratings. At the conclusion of grazing in the second year (22 June), steers were placed on a bermudagrass [Cynodon dactylon (L.) Pers.] pasture, and rectal temperatures and serum prolactin concentrations were monitored for 10 d to assess carryover effects of stocking rate and steroidal implants on recovery from toxicosis-related heat stress. Forage availability differed (P < 0.001) between years, but there were no year x treatment interactions (P > 0.10). There was an implant x stocking rate interaction (P < 0.05) on ADG. Differences between the slopes in the regression equations indicated that ADG responded to implantation when stocking rates were low, but the response diminished as stocking rate increased. Stocking rate did not influence (P = 0.89) postgraze rectal temperature, but the regression intercept for implanted steers was 0.4 degrees C greater (P < 0.05) than for nonimplanted steers, and the difference was consistent across the entire 10-d fescue-free grazing period. Concentrations of prolactin increased during the 10-d fescue-free grazing period, but trends differed due to an implantation x stocking rate interaction (P < 0.05). Results indicate that implantation with progesterone + estradiol benzoate increases ADG with lower stocking rates, but the effect diminishes

  6. Doing More with Less? Toward Increasing the Resolution of Protistan Grazing-rate Measurements.

    NASA Astrophysics Data System (ADS)

    Morison, F.; Menden-Deuer, S.

    2016-02-01

    The dilution method is the standard protocol to quantify phytoplankton grazing-mortality rates and has been key in developing an understanding of protistan grazing impact on ocean primary production. Although the method's extensive use has facilitated the acquisition of a global dataset, its laborious application hinders the sampling resolution needed to fill knowledge gaps remaining at the geographical, seasonal, and vertical scales, and of the effects of climate-related factors influencing grazing magnitude. Here we present a rigorous assessment of an abbreviated method known as the 2-point. We analyzed unpublished results from 77 dilution experiments performed using a series of up to 5 dilutions under a wide range of chlorophyll concentrations and temperatures. We quantified the difference between estimates of both phytoplankton growth and grazing-mortality obtained based on the full dilution series and those obtained when the number of dilutions was reduced to 2. We considered the effect of non-linearity and chlorophyll concentration, and generated quantified estimates of trade-offs when choosing the fraction of seawater in the diluted treatment. Ultimately, we provide an assessment of the reliability of the 2-point method and recommendations on how to apply it.

  7. Zooplankton and the Ocean Carbon Cycle.

    PubMed

    Steinberg, Deborah K; Landry, Michael R

    2017-01-03

    Marine zooplankton comprise a phylogenetically and functionally diverse assemblage of protistan and metazoan consumers that occupy multiple trophic levels in pelagic food webs. Within this complex network, carbon flows via alternative zooplankton pathways drive temporal and spatial variability in production-grazing coupling, nutrient cycling, export, and transfer efficiency to higher trophic levels. We explore current knowledge of the processing of zooplankton food ingestion by absorption, egestion, respiration, excretion, and growth (production) processes. On a global scale, carbon fluxes are reasonably constrained by the grazing impact of microzooplankton and the respiratory requirements of mesozooplankton but are sensitive to uncertainties in trophic structure. The relative importance, combined magnitude, and efficiency of export mechanisms (mucous feeding webs, fecal pellets, molts, carcasses, and vertical migrations) likewise reflect regional variability in community structure. Climate change is expected to broadly alter carbon cycling by zooplankton and to have direct impacts on key species.

  8. Mixotrophy in the Winter Bloom-forming Heterocapsa rotundata: Quantifying Grazing Rates Using Two Methodologies

    NASA Astrophysics Data System (ADS)

    Aceves, A.; Pierson, J. J.; Millette, N.

    2016-02-01

    Mixotrophic plankton are capable of obtaining their energy through photosynthesis and phagocytosis, and have been observed to be common among marine and freshwater dinoflagellates. The role of mixotrophic dinoflagellates in the `microbial loop' has received little attention. Organisms that were only thought to introduce new carbon into the loop through photosynthesis may also consume fixed carbon by ingesting bacteria, making the `microbial loop' more complex that originally conceived. The nanodinoflagellate Heterocapsa rotundata was cultured under various light and nutrient regimes to investigate the role of phototrophy and phagotrophy during winter conditions in the Chesapeake Bay. We quantified grazing rates of H. rotundata on bacteria using two feeding methods, ingestion of polycarbonate microspheres and prey removal experiments. Ingestion of fluorescent microspheres by H. rotundata revealed their ability to phagocytize particles. Using flow cytometry we calculated grazing rates of H. rotundata on bacteria under various light intensities and ammonium concentrations and found that H. rotundata increased phagotrophy at lower light intensities and ammonium was positively correlated with the grazing rates of H. rotundata. We conclude that H. rotundata uses mixotrophy as a primary source for obtaining carbon during the winter when there is limited light and lower temperatures.

  9. The multi-year cumulative effects of alternative stocking rate and grazing management practices on pasture productivity and utilization efficiency.

    PubMed

    McCarthy, B; Delaby, L; Pierce, K M; McCarthy, J; Fleming, C; Brennan, A; Horan, B

    2016-05-01

    The production and utilization of increased quantities of high quality pasture is of paramount importance in pasture-based milk production systems. The objective of this study was to evaluate the cumulative effects of alternative integrated grazing strategies, incorporating alternative stocking rate (SR) and grazing severities, on pasture productivity and grazing efficiency over multiple years within farm systems using perennial ryegrass dominant pastures. Three whole-farm SR treatments were compared over 4 complete grazing seasons (2009 to 2012 inclusive): low (2.51 cows/ha; LSR), medium (2.92 cows/ha; MSR), and high (3.28 cows/ha; HSR). Each system had its own farmlet containing 18 paddocks and remained on the same treatment for the duration of the study. Stocking rate had a significant effect on all grazing variables with the exception of soil fertility status and sward density. Increased SR resulted in increased total annual net pasture accumulation, improved sward nutritive value, and increased grazed pasture utilization. Total annual net pasture accumulation was greatest in HSR [15,410kg of dry matter (DM)/ha], intermediate for MSR (14,992kg of DM/ha), and least for LSR (14,479kg of DM/ha) during the 4-yr study period. A linear effect of SR on net pasture accumulation was detected with an increase in net pasture accumulation of 1,164.4 (SE=432.7) kg of DM/ha for each 1 cow/ha increase in SR. Pregrazing pasture mass and height and postgrazing residual pasture mass and height were greatest for LSR, intermediate for the MSR, and lowest for the HSR. In comparison with the LSR, the imposition of a consistently increased grazing severity coupled with increased whole farm SR in MSR and HSR treatments arrested the decline in sward nutritive value, typically observed during mid-season. Incorporating the individual beneficial effects of SR on pasture accumulation, nutritive value, and utilization efficiency, total proportional energy (unité fourragère lait

  10. Nitrogen rate and application timing affect the yield and risk associated with stockpiling tall fescue for winter grazing

    USDA-ARS?s Scientific Manuscript database

    Stockpiled tall fescue can provide economical winter feed for grazing livestock in the mid-Atlantic of the United States. The objective of this study was to evaluate the effect of N rate and application timing on the yield of stockpiled tall fescue. Four N rates ranging from 0 to 120 lb N/acre wer...

  11. Zooplankton intermittency and turbulence

    NASA Astrophysics Data System (ADS)

    Schmitt, François G.

    2010-05-01

    Planktonic organisms usually live in a turbulent world. Since marine turbulence is characterized by very high Reynolds numbers, it possesses very intermittent fluctuations which in turn affect marine life. We consider here such influence on zooplankton on 2 aspects. First we consider zooplankton motion in the lab. Many copepods display swimming abilities. More and more species have been recently recorded using normal or high speed cameras, and many trajectories have been extracted from these movies and are now available for analysis. These trajectories can be complex, stochastic, with random switching from low velocity to high velocity events and even jumps. These complex trajectories show that an adequate modeling is necessary to understand and characterize them. Here we review the results published in the literature on copepod trajectories. We discuss the random walk, Levy walk modeling and introduce also multifractal random walks. We discuss the way to discriminate between these different walks using experimental data. Stochastic simulations will be performed to illustrate the different families. Second, we consider zooplankton contact rates in the framework of intermittent turbulence. Intermittency may have influence on plankton contact rates. We consider the Particle Stokes number of copepods, in a intermediate dissipation range affected by intermittent fluctuations. We show that they may display preferential concentration effects, and we consider the influence on contact rates of this effect in the intermediate dissipation range.

  12. INTERACTIONS BETWEEN NUTRIENTS,PHYTOPLANKTON GROWTH AND MICROZOOPLANKTON GRAZING RATES IN A GULF OF MEXICO ESTUARY

    EPA Science Inventory

    Juhl, Andrew R. and Michael C. Murrell. Submitted. Phytoplankton Growth and Microzooplankton Grazing in a Gulf of Mexico Estuary. Aquat. Microb. Ecol. 38(1): 147-156, 2005.(ERL,GB 1214).

    Dilution grazing experiments were conducted on 9 dates over a 16-month period in Sant...

  13. Predation on the Invasive Copepod, Pseudodiaptomus forbesi, and Native Zooplankton in the Lower Columbia River: An Experimental Approach to Quantify Differences in Prey-Specific Feeding Rates

    PubMed Central

    Adams, Jesse B.; Bollens, Stephen M.; Bishop, John G.

    2015-01-01

    Invasive planktonic crustaceans have become a prominent feature of aquatic communities worldwide, yet their effects on food webs are not well known. The Asian calanoid copepod, Pseudodiaptomus forbesi, introduced to the Columbia River Estuary approximately 15 years ago, now dominates the late-summer zooplankton community, but its use by native aquatic predators is unknown. We investigated whether three species of planktivorous fishes (chinook salmon, three-spined stickleback, and northern pikeminnow) and one species of mysid exhibited higher feeding rates on native copepods and cladocerans relative to P. forbesi by conducting `single-prey’ feeding experiments and, additionally, examined selectivity for prey types with `two-prey’ feeding experiments. In single-prey experiments individual predator species showed no difference in feeding rates on native cyclopoid copepods (Cyclopidae spp.) relative to invasive P. forbesi, though wild-collected predators exhibited higher feeding rates on cyclopoids when considered in aggregate. In two-prey experiments, chinook salmon and northern pikeminnow both strongly selected native cladocerans (Daphnia retrocurva) over P. forbesi, and moreover, northern pikeminnow selected native Cyclopidae spp. over P. forbesi. On the other hand, in two-prey experiments, chinook salmon, three-spined stickleback and mysids were non- selective with respect to feeding on native cyclopoid copepods versus P. forbesi. Our results indicate that all four native predators in the Columbia River Estuary can consume the invasive copepod, P. forbesi, but that some predators select for native zooplankton over P. forbesi, most likely due to one (or both) of two possible underlying casual mechanisms: 1) differential taxon-specific prey motility and escape responses (calanoids > cyclopoids > daphnids) or 2) the invasive status of the zooplankton prey resulting in naivety, and thus lower feeding rates, of native predators feeding on invasive prey. PMID

  14. Implementation of the zooplankton functional response in plankton models: State of the art, recent challenges and future directions

    NASA Astrophysics Data System (ADS)

    Morozov, Andrew; Poggiale, Jean-Christophe; Cordoleani, Flora

    2012-09-01

    The conventional way of describing grazing in plankton models is based on a zooplankton functional response framework, according to which the consumption rate is computed as the product of a certain function of food (the functional response) and the density/biomass of herbivorous zooplankton. A large amount of literature on experimental feeding reports the existence of a zooplankton functional response in microcosms and small mesocosms, which goes a long way towards explaining the popularity of this framework both in mean-field (e.g. NPZD models) and spatially resolved models. On the other hand, the complex foraging behaviour of zooplankton (feeding cycles) as well as spatial heterogeneity of food and grazer distributions (plankton patchiness) across time and space scales raise questions as to the existence of a functional response of herbivores in vivo. In the current review, we discuss limitations of the ‘classical’ zooplankton functional response and consider possible ways to amend this framework to cope with the complexity of real planktonic ecosystems. Our general conclusion is that although the functional response of herbivores often does not exist in real ecosystems (especially in the form observed in the laboratory), this framework can be rather useful in modelling - but it does need some amendment which can be made based on various techniques of model reduction. We also show that the shape of the functional response depends on the spatial resolution (‘frame’) of the model. We argue that incorporating foraging behaviour and spatial heterogeneity in plankton models would not necessarily require the use of individual based modelling - an approach which is now becoming dominant in the literature. Finally, we list concrete future directions and challenges and emphasize the importance of a closer collaboration between plankton biologists and modellers in order to make further progress towards better descriptions of zooplankton grazing.

  15. An experimental analysis of harmful algae-zooplankton interactions and the ultimate defense

    USGS Publications Warehouse

    Remmel, E.J.; Kohmescher, N.; Larson, J.H.; Hambright, K.D.

    2011-01-01

    We examined effects of the invasive, toxigenic haptophyte Prymnesium parvum on grazing rates, feeding behaviors, and life-history characteristics of clonal lineages of three daphniid zooplankton species. Grazing experiments revealed similar clearance rates for P. parvum and a common green alga. Behavioral observations revealed no significant effects of P. parvum on daphniid feeding behaviors after 30 min, but major declines in appendage beat rates after 1 h. Chronic exposure (10 d) to P. parvum resulted in severe reductions in daphniid growth rates, age at first reproduction, fecundity, and survivorship at densities as low as 7750 cells mL-1. Thus, in addition to direct fish mortality during P. parvum blooms of 50,000-200,000 cells mL-1, the entire food web of an invaded system may be subjected to potentially severe negative consequences even at nonbloom densities of P. parvum. ?? 2011, by the American Society of Limnology and Oceanography, Inc.

  16. Grazing impacts on infiltration rates at Vernal Pools in the Modoc Plateau

    USDA-ARS?s Scientific Manuscript database

    Vernal pools are depressions of land that are seasonally inundated with water. They host rare and endemic plant and animal species and are sensitive to livestock grazing management and climate change impacts on hydrology and vegetation. Climate change forecasts predicting a hotter, drier climate sug...

  17. Photosynthetic characteristics and estimated growth rates indicate grazing is the proximate control of primary production in the equatorial Pacific

    NASA Technical Reports Server (NTRS)

    Cullen, John J.; Lewis, Marlon R.; Davis, Curtiss O.; Barber, Richard T.

    1992-01-01

    Macronutrients persist in the surface layer of the equatorial Pacific because the production of phytoplankton is limited; the nature of this limitation has yet to be resolved. Measurements of photosynthesis as a function of irradiance (P-I) provide information on the control of primary productivity, a question of great biogeochemical importance. Accordingly, P-I was measured in the equatorial Pacific along 150 deg W, during February-March 1988. Diel variability of P-I showed a pattern consistent with nocturnal vertical mixing in the upper 20 m followed by diurnal stratification, causing photoinhibition near the surface at midday. Otherwise, the distribution of photosynthetic parameters with depth and the stability of P-I during simulated in situ incubations over 2 days demonstrated that photoadaptation was nearly complete at the time of sampling: photoadaptation had not been effectively countered by upwelling or vertical mixing. Measurements of P-I and chlorophyll during manipulations of trace elements showed that simple precautions to minimize contamination were sufficient to obtain valid rate measurements and that the specific growth rates of phytoplankton were fairly high in situ, a minimum of 0.6/d. Diel variability of beam attenuation also indicated high specific growth rates of phytoplankton and a strong coupling of production with grazing. It appears that grazing is the proximate control on the standing crop of phytoplankton. Nonetheless, the supply of a trace nutrient such as iron might ultimately regulate productivity by influencing species composition and food-web structure.

  18. Effects of grazing, phosphorus and light on the growth rates of major bacterioplankton taxa in the coastal NW Mediterranean.

    PubMed

    Sánchez, Olga; Koblížek, Michal; Gasol, Josep M; Ferrera, Isabel

    2017-06-01

    Estimation of growth rates is crucial to understand the ecological role of prokaryotes and their contribution to marine biogeochemical cycling. However, there are only a few estimates for individual taxa. Two top-down (grazing) and bottom-up (phosphorus (P) availability) manipulation experiments were conducted under different light regimes in the NW Mediterranean Sea. Growth rate of different phylogenetic groups, including the Bacteroidetes, Rhodobacteraceae, SAR11, Gammaproteobacteria and its subgroups Alteromonadaceae and the NOR5/OM60 clade, were estimated from changes in cell numbers. Maximal growth rates were achieved in the P-amended treatments but when comparing values between treatments (response ratios), the response to predation removal was in general larger than to P-amendment. The Alteromonadaceae displayed the highest rates in both experiments followed by the Rhodobacteraceae, but all groups largely responded to filtration and P-amendment, even the SAR11 which presented low growth rates. Comparing light and dark treatments, growth rates were on average equal or higher in the dark than in the light for all groups, except for the Rhodobacteraceae and particularly the NOR5 clade, groups that contain photoheterotrophic species. These results are useful to evaluate the potential contributions of different bacterial types to biogeochemical processes under changing environmental conditions. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. Genotype x environmental interaction for mature size and rate of maturing for Angus, Brahman, and reciprocal-cross cows grazing bermudagrass or endophyte infected fescue.

    PubMed

    Sandelin, B A; Brown, A H; Brown, M A; Johnson, Z B; Kellogg, D W; Stelzleni, A M

    2002-12-01

    Mature weight and rate of maturing were estimated in 177 Angus, Brahman, and reciprocal-cross cows grazing bermudagrass or endophyte-infected tall fescue over a 4-yr period to evaluate genotype x environment interactions. Data were collected every 28 d until cows were approximately 18 mo of age and then at prebreeding, postcalving, and weaning of calf. All cows with weight data to at least 42 mo of age were included in the analysis. Mature weight and rate of maturing were estimated using the three-parameter growth curve model described by Brody (1945). Data were pooled over year and analyzed by the general linear model procedure of SAS. Included in the models for mature weight and rate of maturing were the independent variables of genotype, environment, and genotype x environment interaction. There was a genotype x environment interaction (P < 0.01) for mature body weight (BW) but not for rate of maturing. Angus cows grazing fescue pastures had greater (P < 0.01) mean mature BW than Angus x Brahman cows grazing bermudagrass (611 +/- 17 vs 546 +/- 16 kg). Angus x Brahman cows grazing bermudagrass had lower (P < 0.05) mean mature BW than Brahman x Angus cows grazing bermudagrass or endophyte-infected fescue and Brahman cows grazing bermudagrass (546 +/- 16 vs 624 +/- 19, 614 +/- 22 and 598 +/- 20 kg, respectively). Brahman cows grazing endophyte-infected fescue had smaller (P < 0.05) mean mature BW than all genotype x forage combinations except for Angus x Brahman cows grazing bermudagrass. Angus cows had a smaller (P < 0.05) mean rate of maturing than Angus x Brahman and Brahman x Angus cows (0.039 +/- 0.002 vs 0.054 +/- 0.002 and 0.049 +/- 0.002%/mo, respectively), respectively, and Angus x Brahman cows had a larger (P < 0.05) mean rate of maturing than Brahman x Angus and Brahman cows (0.054 +/- 0.002 vs 0.049 +/- 0.002 and 0.041 +/- 0.002 %/mo, respectively). There was a direct breed x forage interaction (P < 0.05) for mature BW. These data suggest that the

  20. Nutrient supply, surface currents, and plankton dynamics predict zooplankton hotspots in coastal upwelling systems

    NASA Astrophysics Data System (ADS)

    Messié, Monique; Chavez, Francisco P.

    2017-09-01

    A simple combination of wind-driven nutrient upwelling, surface currents, and plankton growth/grazing equations generates zooplankton patchiness and hotspots in coastal upwelling regions. Starting with an initial input of nitrate from coastal upwelling, growth and grazing equations evolve phytoplankton and zooplankton over time and space following surface currents. The model simulates the transition from coastal (large phytoplankton, e.g., diatoms) to offshore (picophytoplankton and microzooplankton) communities, and in between generates a large zooplankton maximum. The method was applied to four major upwelling systems (California, Peru, Northwest Africa, and Benguela) using latitudinal estimates of wind-driven nitrate supply and satellite-based surface currents. The resulting zooplankton simulations are patchy in nature; areas of high concentrations coincide with previously documented copepod and krill hotspots. The exercise highlights the importance of the upwelling process and surface currents in shaping plankton communities.

  1. Linkages between grazing history and herbivore exclusion on decomposition rates in mineral soils of subalpine grasslands

    Treesearch

    Alan G. Haynes; Martin Schutz; Nina Buchmann; Deborah S. Page-Dumroese; Matt D. Busse; Anita C. Risch

    2014-01-01

    Herbivore-driven changes to soil properties can influence the decomposition rate of organic material and therefore soil carbon cycling within grassland ecosystems. We investigated how aboveground foraging mammalian and invertebrate herbivores affect mineral soil decomposition rates and associated soil properties in two subalpine vegetation types (shortgrass and tall-...

  2. Mesozooplankton grazing during spring sea-ice conditions in the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Campbell, Robert G.; Ashjian, Carin J.; Sherr, Evelyn B.; Sherr, Barry F.; Lomas, Michael W.; Ross, Celia; Alatalo, Philip; Gelfman, Celia; Keuren, Donna Van

    2016-12-01

    Mesozooplankton (copepods and euphausiids) grazing rates and prey preferences were determined during a series of three research cruises to the eastern Bering Sea in spring 2008, 2009, and 2010. Chlorophyll was dominated by large cells (>5 μm), especially at bloom locations where they usually comprised greater than 90% of the total chlorophyll biomass. The relative importance of microzooplankton to the prey field biomass decreased with increasing chlorophyll concentration, and was less than 10% of the total prey biomass in ice-edge bloom regions. Overall, microzooplankton was the preferred prey of the mesozooplankton, although phytoplankton/ice algae were the dominant component of the diet because of their much greater biomass, especially during blooms. There were differences between mesozooplankton species in their prey preferences: Metridia pacifica, Pseudocalanus spp. and Calanus spp. had the strongest preference for microzooplankton prey, while euphausiids (Thysanoessa spp.) and Neocalanus flemingeri/plumchrus appeared to feed non-selectively on all prey items. Mesozooplankton exhibited a saturating feeding response to chlorophyll concentration (Holling's type II) that could be modeled by Michaelis-Menten equations. Taxa-specific maximum ingestion rates generally followed allometric theory, with smaller zooplankton having higher feeding rates than larger zooplankton, and ranged from about 4-30% body carbon day-1. Trophic cascades during grazing experiments could result in a substantial underestimate of chlorophyll ingestion rates, especially for those taxa that had a strong preference for microzooplankton. Grazing impacts by mesozooplankton on the integrated chlorophyll biomass and primary production were 2.7±4.4 and 26±48% day-1, respectively. Impacts increased significantly with increasing mesozooplankton biomass, which increased from early to late spring. However, grazing impacts were extremely low in ice-edge bloom regions. Our findings suggest that even

  3. Do Bells Affect Behaviour and Heart Rate Variability in Grazing Dairy Cows?

    PubMed Central

    Johns, Julia; Patt, Antonia; Hillmann, Edna

    2015-01-01

    In alpine regions cows are often equipped with bells. The present study investigated the impact of wearing a bell on behaviour and heart rate variability in dairy cows. Nineteen non-lactating Brown-Swiss cows with bell experience were assigned to three different treatments. For 3 days each, cows were equipped with no bell (control), with a bell with inactivated clapper (silent bell) or with a functional bell (functional bell). The bells weighed 5.5 kg and had frequencies between 532 Hz and 2.8 kHz and amplitudes between 90 and 113 dB at a distance of 20 cm. Data were collected on either the first and third or on all 3 days of each treatment. Whereas duration of rumination was reduced with a functional bell and a silent bell compared with no bell, feeding duration was reduced with a silent bell and was intermediate with a functional bell. Head movements were reduced when wearing a silent bell compared with no bell and tended to be reduced when wearing a functional compared to no bell. With a functional bell, lying duration was reduced by almost 4 hours on the third day of treatment compared with the first day with a functional bell and compared with no bell or a silent bell. All additional behavioural measures are consistent with the hypothesis of a restriction in the behaviour of the cows wearing bells, although this pattern did not reach significance. There was no treatment effect on heart rate variability, suggesting that the bells did not affect vago-sympathetic balance. An effect of experimental day was found for only 1 out of 10 behavioural parameters, as shown by a decrease in lying with a functional bell on day 3. The results indicate behavioural changes in the cows wearing a bell over 3 days, without indication of habituation to the bell. Altogether, the behavioural changes suggest that the behaviour of the cows was disturbed by wearing a bell. If long-lasting, these effects may have implications for animal welfare. PMID:26110277

  4. Metabolizable protein supply while grazing dormant winter forage during heifer development alters pregnancy and subsequent in-herd retention rate.

    PubMed

    Mulliniks, J T; Hawkins, D E; Kane, K K; Cox, S H; Torell, L A; Scholljegerdes, E J; Petersen, M K

    2013-03-01

    Two studies were conducted to evaluate the effects of postweaning management of British crossbred heifers on growth and reproduction. In Exp. 1, 239 spring-born, crossbred heifers were stratified by weaning BW (234 ± 1 kg) and allotted randomly to 1 of 2 treatments. Treatments were fed at a rate equivalent to 1.14 kg/d while grazing dormant forage (6.5% CP and 80% NDF, DM basis) and were 1) 36% CP containing 36% RUP (36RUP) or 2) 36% CP containing 50% RUP (50RUP). Supplementation was initiated in February (1995 and 1996) or November (1997 and 1998) and terminated at the onset of breeding season (mid May). Heifers were weighed monthly up to breeding and again at time of palpation. After timed AI, heifers were exposed to breeding bulls for 42 ± 8 d. In Exp. 2, 191 spring-born, crossbred heifers were stratified by weaning BW to treatments. Heifer development treatments were 1) pasture developed and fed 0.9 kg/day of a 36% CP supplement containing 36% RUP (36RUP), 2) pasture developed and fed 0.9 kg/day of a 36% CP supplement containing 50% RUP (50RUP), and 3) corn silage-based growing diet in a drylot (DRYLOT). Heifers receiving 36RUP and 50RUP treatments were developed on dormant forage. Treatments started in February and ended at the onset of a 45-d breeding season in May. Heifer BW and hip height were taken monthly from initiation of supplementation until breeding and at pregnancy diagnosis. In Exp. 1, BW was not different (P ≥ 0.27) for among treatments at all measurement times. However, 50RUP heifers had greater (P = 0.02; 80 and 67%) pregnancy rates than 36RUP heifers. In Exp. 2, DRYLOT heifers had greater (P < 0.01) BW at breeding than 36RUP or 50RUP developed heifers. However, BW at pregnancy diagnosis was not different (P = 0.24) for between treatments. Pregnancy rates tended to be greater (P = 0.10) for 50RUP heifers than 36RUP and DRYLOT. Net return per heifer was US$99.71 and $87.18 greater for 50RUP and 36RUP heifers, respectively, compared with

  5. Acoustic classification of zooplankton

    NASA Astrophysics Data System (ADS)

    Martin Traykovski, Linda V.

    1998-11-01

    Work on the forward problem in zooplankton bioacoustics has resulted in the identification of three categories of acoustic scatterers: elastic-shelled (e.g. pteropods), fluid-like (e.g. euphausiids), and gas-bearing (e.g. siphonophores). The relationship between backscattered energy and animal biomass has been shown to vary by a factor of ~19,000 across these categories, so that to make accurate estimates of zooplankton biomass from acoustic backscatter measurements of the ocean, the acoustic characteristics of the species of interest must be well-understood. This thesis describes the development of both feature based and model based classification techniques to invert broadband acoustic echoes from individual zooplankton for scatterer type, as well as for particular parameters such as animal orientation. The feature based Empirical Orthogonal Function Classifier (EOFC) discriminates scatterer types by identifying characteristic modes of variability in the echo spectra, exploiting only the inherent characteristic structure of the acoustic signatures. The model based Model Parameterisation Classifier (MPC) classifies based on correlation of observed echo spectra with simplified parameterisations of theoretical scattering models for the three classes. The Covariance Mean Variance Classifiers (CMVC) are a set of advanced model based techniques which exploit the full complexity of the theoretical models by searching the entire physical model parameter space without employing simplifying parameterisations. Three different CMVC algorithms were developed: the Integrated Score Classifier (ISC), the Pairwise Score Classifier (PSC) and the Bayesian Probability Classifier (BPC); these classifiers assign observations to a class based on similarities in covariance, mean, and variance, while accounting for model ambiguity and validity. These feature based and model based inversion techniques were successfully applied to several thousand echoes acquired from broadband (~350 k

  6. Amazing Grazing.

    ERIC Educational Resources Information Center

    Peterson, Cris

    Countless acres of grasslands stretch across the American West. Centuries ago, bison roamed the range freely and lived off the grass. By the 19th century, herds of cattle grazed the same land. Over time, much of the original grassland was either plowed and planted or trampled to dust, causing the topsoil to dry up and blow away. Today many…

  7. Does cattle grazing of dual-purpose wheat accelerate the rate of stubble decomposition and nutrients released

    USDA-ARS?s Scientific Manuscript database

    Decomposition and nutrient release of winter annual forages in integrated crop-livestock systems could be affected by the resultant alterations in structure and quality of residues caused by grazing, but little information is available to test this hypothesis. Information on residue dynamics is need...

  8. Effects of stocking rate, forage management, and grazing management on performance and economics of cow-calf production in Southwest Arkansas.

    PubMed

    Beck, P A; Stewart, C B; Sims, M B; Gadberry, M S; Jennings, J A

    2016-09-01

    The objective this research was to determine the effect of application of multiple grazing management practices at 2 stocking rates (SR) on the productivity and economics of the cow-calf enterprise in the Southeastern United States over a 4-yr period. Pasture management systems included: continuous grazing management at a moderate SR (0.8 ha/cow; CG) without additional forage management, rotational grazing management at a moderate SR (0.8 ha/cow (MR) with addition of stockpiled bermudagrass [ (L.) Pers.] and complementary cool season annuals, and rotational grazing management similar to MR but with a high SR (0.4 ha/cow; HR). Stockpiling in MR and HR was managed by fertilization of 0.2 ha/cow of bermudagrass in early August with 168 kg ammonium nitrate and deferring grazing until November. Wheat (; 112 kg/ha) and annual ryegrass ( Lam.; 28 kg/ha) were interseeded (0.2 ha/cow) in HR and MR with a no-till drill in the fall. Cow and calf performance and economics data were analyzed by ANOVA using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) and pregnancy percentage was analyzed using the GLIMMIX procedure of SAS; pasture was the experimental unit and year was the random block. Hay feeding days decreased ( < 0.01) from 107 ± 10.9 d for CG to 37 ± 10.9 d for HR, which was further reduced ( = 0.01) to 15 ± 10.9 d for MR. Pregnancy percentage did not differ ( = 0.20) among treatments. Weaning BW in CG (237 ± 7.3 kg) tended ( = 0.09) to be greater than in MR (227 ± 7.3 kg) and were greater ( < 0.01) than in HR (219 ± 7.3 kg). However, total weaning BW per hectare was 89% greater ( < 0.01) for HR compared with CG and MR, which did not differ ( = 0.31). With rotational stocking, there was the opportunity to harvest excess forage as hay in both MR and HR with a net value of US$52.90/ha ± 25.73 and $15.50/ha ± 25.73, respectively. Net returns per hectare did not differ ( = 0.30) between CG ($429 ± 63.0/ha) and MR ($479 ± 63.0/ha) but were increased ( < 0

  9. Mesozooplankton production, grazing and respiration in the Bay of Bengal: Implications for net heterotrophy

    NASA Astrophysics Data System (ADS)

    Fernandes, Veronica; Ramaiah, N.

    2016-03-01

    Mesozooplankton samples were collected from the mixed layer along a central (along 88°E) and a western transect in the Bay of Bengal during four seasons covered between 2001 and 2006 in order to investigate spatio-temporal variability in their biomass. At these stations, grazing and respiration rates were measured from live zooplankton hauled in from the surface during December 2005. Akin to the mesozooplankton "paradox" in the central and eastern Arabian Sea, biomass in the mixed layer was more or less invariant in the central and western Bay of Bengal, even as the chl a showed marginal temporal variation. By empirical equation, the mesozooplankton production rate calculated to be 70-246 mg C m- 2 d- 1 is on par with the Arabian Sea. Contrary to the conventional belief, mesozooplankton grazing impact was up to 83% on primary production (PP). Low PP coupled with very high zooplankton production (70% of PP) along with abundant bacterial production (50% of the PP; Ramaiah et al., 2009) is likely to render the Bay of Bengal net heterotrophic, especially during the spring intermonsoon. Greater estimates of fecal pellet-carbon egestion by mesozooplankton compared to the average particulate organic carbon flux in sediment traps, implies that much of the matter is recycled by heterotrophic communities in the mixed layer facilitating nutrient regeneration for phytoplankton growth. We also calculated that over a third of the primary production is channelized for basin-wide zooplankton respiration that accounts for 52 Mt C annually. In the current scenario of global warming, if low (primary) productive warm pools like the Bay of Bengal continue to be net heterotrophic, negative implications like enhanced emission of CO2 to the atmosphere, increased particulate flux to the deeper waters and greater utilization of dissolved oxygen resulting in expansion of the existing oxygen minimum zone are imminent.

  10. Substitution rate and milk yield response to corn silage supplementation of late-lactation dairy cows grazing low-mass pastures at 2 daily allowances in autumn.

    PubMed

    Pérez-Prieto, L A; Peyraud, J L; Delagarde, R

    2011-07-01

    Feed costs in dairy production systems may be decreased by extending the grazing season to periods such as autumn when grazing low-mass pastures is highly probable. The aim of this autumn study was to determine the effect of corn silage supplementation [0 vs. 8 kg of dry matter (DM) of a mixture 7:1 of corn silage and soybean meal] on pasture intake (PI), milk production, and grazing behavior of dairy cows grazing low-mass ryegrass pastures at 2 daily pasture allowances (PA; low PA=18 vs. high PA=30 kg of DM/cow above 2.5 cm). Twelve multiparous Holstein cows were used in a 4 × 4 Latin square design with 14-d periods. Pre-grazing pasture mass and pre-grazing plate meter pasture height averaged 1.8 t of DM/ha (above 2.5 cm) and 6.3 cm, respectively. The quality of the offered pasture (above 2.5 cm) was low because of dry conditions before and during the experiment (crude protein=11.5% of DM; net energy for lactation=5.15 MJ/kg of DM; organic matter digestibility=61.9%). The interaction between PA and supplementation level was significant for PI but not for milk production. Supplementation decreased PI from 11.6 to 7.6 kg of DM/d at low PA and from 13.1 to 7.3 kg of DM/d at high PA. The substitution rate was, therefore, lower at low than at high PA (0.51 vs. 0.75). Pasture intake increased with increasing PA in unsupplemented treatments, and was not affected by PA in supplemented treatments. Milk production averaged 13.5 kg/d and was greater at high than at low PA (+1.4 kg/d) and in supplemented than unsupplemented treatments (+5.2 kg/d). Milk fat concentration averaged 4.39% and was similar between treatments. Milk protein concentration increased from 3.37 to 3.51% from unsupplemented to supplemented treatments, and did not vary according to PA. Grazing behavior parameters were only affected by supplementation. On average, daily grazing time decreased (539 vs. 436 min) and daily ruminating time increased (388 vs. 486 min) from 0 to 8 kg of supplement DM. The PI

  11. Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary

    USGS Publications Warehouse

    Kimmerer, W.J.; Burau, J.R.; Bennett, W.A.

    1998-01-01

    In many estuaries, maxima in turbidity and abundance of several common species of zooplankton occur in the low salinity zone (LSZ) in the range of 0.5-6 practical salinity units (psu). Analysis of zooplankton abundance from monitoring in 1972-1987 revealed that historical maxima in abundance of the copepod Eurytemora affinis and the mysid Neomysis mercedis, and in turbidity as determined from Secchi disk data, were close to the estimated position of 2 psu bottom salinity. The copepod Sinocalanus doerrii had a maximum slightly landward of that of E. affinis. After 1987 these maxima decreased and shifted to a lower salinity, presumably because of the effects of grazing by the introduced clam Potamocorbula amurensis. At the same time, the copepod Pseudodiaptomus forbesi, the mysid Acanthomysis sp., and amphipods became abundant with peaks at salinity around 0.2-0.5 psu. Plausible mechanisms for maintenance of these persistent abundance peaks include interactions between variation in flow and abundance, either in the vertical or horizontal plane, or higher net population growth rate in the peaks than seaward of the peaks. In spring of 1994, a dry year, we sampled in and near the LSZ using a Lagrangian sampling scheme to follow selected isohalines while sampling over several complete tidal cycles. Acoustic Doppler current profilers were used to provide detailed velocity distributions to enable us to estimate longitudinal fluxes of organisms. Stratification was weak and gravitational circulation nearly absent in the LSZ. All of the common species of zooplankton migrated vertically in response to the tides, with abundance higher in the water column on the flood than on the ebb. Migration of mysids and amphipods was sufficient to override net seaward flow to produce a net landward flux of organisms. Migration of copepods, however, was insufficient to reverse or even greatly diminish the net seaward flux of organisms, implying alternative mechanisms of position maintenance.

  12. Life strategy and grazing intensity responses of Brachionus calyciflorus fed on different concentrations of microcystin-producing and microcystin-free Microcystis aeruginosa

    NASA Astrophysics Data System (ADS)

    Liang, Ye; Ouyang, Kai; Chen, Xinglan; Su, Yuqi; Yang, Jiaxin

    2017-02-01

    The occurrence of Microcystis blooms is a worldwide concern due to the numerous adverse effects on zooplankton. We therefore hypothesized that the cyanobacterium Microcystis aeruginosa is harmful to rotifer growth. Population and individual experiments were conducted with the same proportional volumes of Chlorella and Microcystis for given food densities. Life-table parameters, life-history traits, and the grazing intensity of Brachionus calyciflorus were evaluated after they had fed on microcystin-producing and microcystin-free Microcystis, both alone and combined with an edible alga (Chlorella pyrenoidosa), at concentrations of 1 × 105, 1 × 106, and 1 × 107 cells mL-1. The results showed that the interactive effects of food density and type appeared to be synergistic on generation time (T), net reproduction rate (R0), body length, swimming speed, and reproduction time. In contrast, these effects appeared to be antagonistic on intrinsic growth rate (r), finite rate of increase (λ), time to first brood, post-reproductive time and total offspring per female. The grazing rate of rotifers decreased with grazing time. Although the toxins released after grazing on M. aeruginosa had negative effects on rotifer growth and reproduction, B. calyciflorus changed its life strategy and grazing intensity in response to eutrophic conditions.

  13. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  14. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  15. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  16. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... of grazing land or pastureland for the county, rated by the U.S. Drought Monitor as having a: (i) D2 (severe drought) intensity in any area of the county for at least 8 consecutive weeks during the normal...

  17. Acoustic insights into the zooplankton dynamics of the eastern Weddell Sea

    NASA Astrophysics Data System (ADS)

    Cisewski, Boris; Strass, Volker H.

    2016-05-01

    The success of any efforts to determine the effects of climate change on marine ecosystems depends on understanding in the first instance the natural variations, which contemporarily occur on the interannual and shorter time scales. Here we present results on the environmental controls of zooplankton distribution patterns and behaviour in the eastern Weddell Sea, Southern Ocean. Zooplankton abundance and vertical migration are derived from the mean volume backscattering strength (MVBS) and the vertical velocity measured by moored acoustic Doppler current profilers (ADCPs), which were deployed simultaneously at 64°S, 66.5°S and 69°S along the Greenwich Meridian from February, 2005, until March, 2008. While these time series span a period of full three years they resolve hourly changes. A highly persistent behavioural pattern found at all three mooring locations is the synchronous diel vertical migration (DVM) of two distinct groups of zooplankton that migrate between a deep residence depth during daytime and a shallow depth during nighttime. The DVM was closely coupled to the astronomical daylight cycles. However, while the DVM was symmetric around local noon, the annual modulation of the DVM was clearly asymmetric around winter solstice or summer solstice, respectively, at all three mooring sites. DVM at our observation sites persisted throughout winter, even at the highest latitude exposed to the polar night. Since the magnitude as well as the relative rate of change of illumination is minimal at this time, we propose that the ultimate causes of DVM separated from the light-mediated proximal cue that coordinates it. In all three years, a marked change in the migration behaviour occurred in late spring (late October/early November), when DVM ceased. The complete suspension of DVM after early November is possibly caused by the combination of two factors: (1) increased availability of food in the surface mixed layer provided by the phytoplankton spring bloom, and

  18. Application of overall dynamic body acceleration as a proxy for estimating the energy expenditure of grazing farm animals: relationship with heart rate.

    PubMed

    Miwa, Masafumi; Oishi, Kazato; Nakagawa, Yasuhiro; Maeno, Hiromichi; Anzai, Hiroki; Kumagai, Hajime; Okano, Kanji; Tobioka, Hisaya; Hirooka, Hiroyuki

    2015-01-01

    Estimating the energy expenditure of farm animals at pasture is important for efficient animal management. In recent years, an alternative technique for estimating energy expenditure by measuring body acceleration has been widely performed in wildlife and human studies, but the availability of the technique in farm animals has not yet been examined. In the present study, we tested the potential use of an acceleration index, overall dynamic body acceleration (ODBA), as a new proxy for estimating the energy expenditure of grazing farm animals (cattle, goats and sheep) at pasture with the simultaneous evaluation of a conventional proxy, heart rate. Body accelerations in three axes and heart rate for cows (n = 8, two breeds), goats (n = 6) and sheep (n = 5) were recorded, and the effect of ODBA calculated from the body accelerations on heart rate was analyzed. In addition, the effects of the two other activity indices, the number of steps and vectorial dynamic body acceleration (VeDBA), on heart rate were also investigated. The results of the comparison among three activity indices indicated that ODBA was the best predictor for heart rate. Although the relationship between ODBA and heart rate was different between the groups of species and breeds and between individuals (P<0.01), the difference could be explained by different body weights; a common equation could be established by correcting the body weights (M: kg): heart rate (beats/min) = 147.263∙M-0.141 + 889.640∙M-0.179∙ODBA (g). Combining this equation with the previously reported energy expenditure per heartbeat, we estimated the energy expenditure of the tested animals, and the results indicated that ODBA is a good proxy for estimating the energy expenditure of grazing farm animals across species and breeds. The utility and simplicity of the procedure with acceleration loggers could make the accelerometry technique a worthwhile option in field research and commercial farm use.

  19. Effects of nitrogen application rate and a nitrification inhibitor dicyandiamide on ammonia oxidizers and N2O emissions in a grazed pasture soil.

    PubMed

    Dai, Yu; Di, Hong J; Cameron, Keith C; He, Ji-Zheng

    2013-11-01

    Ammonia oxidizers, including ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) are important drivers of a key step of the nitrogen cycle - nitrification, which affects the production of the potent greenhouse gas, nitrous oxide (N2O). A field experiment was conducted to determine the effect of nitrogen application rates and the nitrification inhibitor dicyandiamide (DCD) on the abundance of AOB and AOA and on N2O emissions in a grazed pasture soil. Nitrogen (N) was applied at four different rates, with urea applied at 50 and 100 kg N ha(-1) and animal urine at 300 and 600 kg N ha(-1). DCD was applied to some of the N treatments at 10 kg ha(-1). The results showed that the AOB amoA gene copy numbers were greater than those of AOA. The highest ratio of the AOB to AOA amoA gene copy numbers was 106.6 which occurred in the urine-N 600 treatment. The AOB amoA gene copy numbers increased with increasing nitrogen application rates. DCD had a significant impact in reducing the AOB amoA gene copy numbers especially in the high nitrogen application rates. N2O emissions increased with the N application rates. DCD had the most significant effect in reducing the daily and total N2O emissions in the highest nitrogen application rate. The greatest reduction of total N2O emissions by DCD was 69% in the urine-N 600 treatment. The reduction in the N2O emission factor by DCD ranged from 58% to 83%. The N2O flux and NO3(-)-N concentrations were significantly correlated to the growth of AOB, rather than AOA. This study confirms the importance of AOB in nitrification and the effect of DCD in inhibiting AOB growth and in decreasing N2O emissions in grazed pasture soils under field conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Ecology of grazing lawns in Africa.

    PubMed

    Hempson, Gareth P; Archibald, Sally; Bond, William J; Ellis, Roger P; Grant, Cornelia C; Kruger, Fred J; Kruger, Laurence M; Moxley, Courtney; Owen-Smith, Norman; Peel, Mike J S; Smit, Izak P J; Vickers, Karen J

    2015-08-01

    Grazing lawns are a distinct grassland community type, characterised by short-stature and with their persistence and spread promoted by grazing. In Africa, they reveal a long co-evolutionary history of grasses and large mammal grazers. The attractiveness to grazers of a low-biomass sward lies in the relatively high quality of forage, largely due to the low proportion of stem material in the sward; this encourages repeat grazing that concomitantly suppresses tall-grass growth forms that would otherwise outcompete lawn species for light. Regular grazing that prevents shading and maintains sward quality is thus the cornerstone of grazing lawn dynamics. The strong interplay between abiotic conditions and disturbance factors, which are central to grazing lawn existence, can also cause these systems to be highly dynamic. Here we identify differences in growth form among grazing lawn grass species, and assess how compositional differences among lawn types, as well as environmental variables, influence their maintenance requirements (i.e. grazing frequency) and vulnerability to degradation. We also make a clear distinction between the processes of lawn establishment and lawn maintenance. Rainfall, soil nutrient status, grazer community composition and fire regime have strong and interactive influences on both processes. However, factors that concentrate grazing pressure (e.g. nutrient hotspots and sodic sites) have more bearing on where lawns establish. Similarly, we discuss the relevance of enhanced rates of nitrogen cycling and of sodium levels to lawn maintenance. Grazer community composition and density has considerable significance to grazing lawn dynamics; not all grazers are adapted to foraging on short-grass swards, and differences in body size and relative mouth dimensions determine which species are able to convert tall-grass swards into grazing lawns under different conditions. Hence, we evaluate the roles of different grazers in lawn dynamics, as well as the

  1. INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)

    EPA Science Inventory

    The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

  2. Investigating long-term interactions between phytoplankton and zooplankton in the NE Atlantic and North Sea

    NASA Astrophysics Data System (ADS)

    Khouri, R.; Beaulieu, C.; Henson, S.; Martin, A. P.; Edwards, M.

    2016-02-01

    It is believed that changes in phytoplankton community have happened in the North Sea and NE Atlantic in the past decades. Since phytoplankton are the base of the marine food web, it is essential to understand the causes of such behaviour due its potential to induce change in the wider ecosystem. Whilst the impact of environmental controls, such as climate, have received considerable attention, phytoplankton can also be affected by zooplankton grazing. We investigate how changes in zooplankton impact phytoplankton populations and community composition, and vice-versa. We use data from the Continuous Plankton Recorder survey, an unique dataset that uses the same sampling methodology since 1958 and thus provides long and comparable plankton time-series. We apply statistical modelling to describe the interaction between phytoplankton and zooplankton. The analysis is inspired from techniques available in econometrics literature, which do not require assumptions of normality, independence or stationarity of the time-series. In particular, we discuss wether climatic factors or zooplankton grazing are more relevant to the variability in phytoplankton abundance and community composition.

  3. MEASURING INVERTEBRATE GRAZING ON SEAGRASSES AND EPIPHYTES

    EPA Science Inventory

    The chapter describes methods to assess grazing rates, grazer preferences, and grazer impacts, by mobile organisms living in the canopy or in the rhizome layer in any seagrass system. One set of methods quantifies grazing activity in small to medium sized, mobile organisms livin...

  4. Metabolizable protein supply alters pregnancy and subsequent retention rate during heifer development while grazing dormant winter forage

    USDA-ARS?s Scientific Manuscript database

    Type of heifer development system can have major impact on the future productivity and retention rate of the cowherd. Therefore, the objective of this experiment was to determine growth, reproductive performance, retention rate, and economic efficiency of heifer’s developed in a range raised (with ...

  5. High mortality of Red Sea zooplankton under ambient solar radiation.

    PubMed

    Al-Aidaroos, Ali M; El-Sherbiny, Mohsen M O; Satheesh, Sathianeson; Mantha, Gopikrishna; Agustī, Susana; Carreja, Beatriz; Duarte, Carlos M

    2014-01-01

    High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h(-1), five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM) 12±5.6 h(-1)% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.

  6. Acoustic discrimination of Southern Ocean zooplankton

    NASA Astrophysics Data System (ADS)

    Brierley, Andrew S.; Ward, Peter; Watkins, Jonathan L.; Goss, Catherine

    Acoustic surveys in the vicinity of the sub-Antarctic island of South Georgia during a period of exceptionally calm weather revealed the existence of a number of horizontally extensive yet vertically discrete scattering layers in the upper 250 m of the water column. These layers were fished with a Longhurst-Hardy plankton recorder (LHPR) and a multiple-opening 8 m 2 rectangular mid-water trawl (RMT8). Analysis of catches suggested that each scattering layer was composed predominantly of a single species (biovolume>95%) of either the euphausiids Euphausia frigida or Thysanöessa macrura, the hyperiid amphipod Themisto gaudichaudii, or the eucalaniid copepod Rhincalanus gigas. Instrumentation on the nets allowed their trajectories to be reconstructed precisely, and thus catch data to be related directly to the corresponding acoustic signals. Discriminant function analysis of differences between mean volume backscattering strength at 38, 120 and 200 kHz separated echoes originating from each of the dominant scattering layers, and other signals identified as originating from Antarctic krill ( Euphausia superba), with an overall correct classification rate of 77%. Using echo intensity data alone, gathered using hardware commonly employed for fishery acoustics, it is therefore possible to discriminate in situ between several zooplanktonic taxa, taxa which in some instances exhibit similar gross morphological characteristics and have overlapping length- frequency distributions. Acoustic signals from the mysid Antarctomysis maxima could also be discriminated once information on target distribution was considered, highlighting the value of incorporating multiple descriptors of echo characteristics into signal identification procedures. The ability to discriminate acoustically between zooplankton taxa could be applied to provide improved acoustic estimates of species abundance, and to enhance field studies of zooplankton ecology, distribution and species interactions.

  7. Contribution and pathways of diazotroph-derived nitrogen to zooplankton during the VAHINE mesocosm experiment in the oligotrophic New Caledonia lagoon

    NASA Astrophysics Data System (ADS)

    Hunt, Brian P. V.; Bonnet, Sophie; Berthelot, Hugo; Conroy, Brandon J.; Foster, Rachel A.; Pagano, Marc

    2016-05-01

    In oligotrophic tropical and subtropical oceans, where strong stratification can limit the replenishment of surface nitrate, dinitrogen (N2) fixation by diazotrophs can represent a significant source of nitrogen (N) for primary production. The VAHINE (VAriability of vertical and tropHIc transfer of fixed N2 in the south-wEst Pacific) experiment was designed to examine the fate of diazotroph-derived nitrogen (DDN) in such ecosystems. In austral summer 2013, three large ( ˜ 50 m3) in situ mesocosms were deployed for 23 days in the New Caledonia lagoon, an ecosystem that typifies the low-nutrient, low-chlorophyll environment, to stimulate diazotroph production. The zooplankton component of the study aimed to measure the incorporation of DDN into zooplankton biomass, and assess the role of direct diazotroph grazing by zooplankton as a DDN uptake pathway. Inside the mesocosms, the diatom-diazotroph association (DDA) het-1 predominated during days 5-15 while the unicellular diazotrophic cyanobacteria UCYN-C predominated during days 15-23. A Trichodesmium bloom was observed in the lagoon (outside the mesocosms) towards the end of the experiment. The zooplankton community was dominated by copepods (63 % of total abundance) for the duration of the experiment. Using two-source N isotope mixing models we estimated a mean ˜ 28 % contribution of DDN to zooplankton nitrogen biomass at the start of the experiment, indicating that the natural summer peak of N2 fixation in the lagoon was already contributing significantly to the zooplankton. Stimulation of N2 fixation in the mesocosms corresponded with a generally low-level enhancement of DDN contribution to zooplankton nitrogen biomass, but with a peak of ˜ 73 % in mesocosm 1 following the UCYN-C bloom. qPCR analysis targeting four of the common diazotroph groups present in the mesocosms (Trichodesmium, het-1, het-2, UCYN-C) demonstrated that all four were ingested by copepod grazers, and that their abundance in copepod

  8. Nitrogen Isotopes as an Indicator of Long-Term N Cycling in a Grazed Temperate Pasture Receiving Different Rates of Superphosphate Fertilizer and Irrigation for ~50 Years

    NASA Astrophysics Data System (ADS)

    Mudge, P. L.; Schipper, L. A.; Ghani, A.; Baisden, W. T.; Dodd, M.

    2010-12-01

    Pastoral agriculture is the dominant land use in New Zealand and intensification (as a result of fertilizer inputs and in some areas irrigation) has led to increased nitrogen (N) losses to the wider environment. An indicator that could identify soils which are vulnerable to N loss would be useful for the development of management practices and regulations aimed at reducing unwanted N losses. The natural abundance of 15N relative to 14N (δ15N) in soils is one potential indicator. Most N cycle processes associated with N losses (e.g. nitrification, denitrification, and volatilisation) discriminate against 15N and therefore soil δ15N could provide an indication of cumulative N losses. In this study we measured δ15N in archived soils from two long-term field trials receiving different rates of superphosphate fertilizer and irrigation. Both trials were in mid-Canterbury, New Zealand and were grazed by sheep. The fertilizer trial began in 1952, and treatments used were the control (nilP), 376 kg superphosphate ha-1 y-1 (376PA) and a treatment where 376 kg superphosphate ha-1 y-1 was applied between 1952 and 1957, no fertilizer from 1958 to 1979 and then 250 kg superphosphate ha-1 y-1 from 1980 to 2009 (376-0-250PA). The irrigation trial was initiated in 1949 and ceased in 2002. The dryland treatment and treatments irrigated when soil moisture was 10% and 20% were used in this study. From 1958, soil samples (0-75 mm depth) were taken annually from each trial, air dried and archived. Soil samples at four year intervals were analysed for this study. Pasture production varied considerably between treatments, with higher rates of fertilizer and irrigation promoting greater pasture growth and therefore higher grazing intensities. Initially δ15N was about the same (3.3‰) in all treatments of both trials. δ15N in the 376PA treatment of the fertilizer trial increased gradually with time and by 2009 was 4.5‰. In the 376-0-250PA treatment, δ15N stayed constant until about

  9. Effect of bait delivery rate in a GreenFeed system on methane emission estimates from cattle grazing rangeland

    USDA-ARS?s Scientific Manuscript database

    Two experiments were conducted to evaluate the effect of bait delivery rate on methane emission estimates measured by a GreenFeed system (GFS; C-Lock, Inc., Rapid City, SD). The manufacture recommends that cattle have a minimum visit time of 3 minutes so that at least 3 eructations are captured to ...

  10. Metabolizable protein supply while grazing dormant winter forage during heifer development alters pregnancy and subsequent in-herd retention rate

    USDA-ARS?s Scientific Manuscript database

    Two studies were conducted to evaluate effects of post-weaning management of British crossbred heifers on growth and reproduction. In Exp. 1, 239 spring-born, crossbred heifers were stratified by weaning BW and allotted randomly to 1 of 2 treatments. Treatments were fed at rate equivalent to 1.1 k...

  11. Effect of stocking rate and supplementation on performance of dairy cows grazing native grassland in small-scale systems in the highlands of central Mexico.

    PubMed

    Sainz-Sánchez, Pedro Alan; López-González, Felipe; Estrada-Flores, Julieta Gertrudis; Martínez-García, Carlos Galdino; Arriaga-Jordán, Carlos Manuel

    2017-01-01

    The use and management of native grassland for dairy production during the rainy season was studied on two small-scale dairy farms in the highlands of central Mexico. Two stocking rates (2 and 4 cows/ha) and two levels of supplementation with commercial concentrate (4 and 6 kg/cow/day) under grazing were given to 12 milking Holstein cows in a 4 × 4 Latin square design replicated three times in a factorial arrangement. Net herbage accumulation (NHA), sward height, chemical composition, and in vitro digestibility of organic matter were recorded for the grassland, as well as vegetation cover and herbage mass 12 weeks post experiment. Animal performance variables were milk yield and composition, live weight, and body condition score. A partial budget analysis of feeding costs, returns, and margins was calculated. There were no differences between periods for NHA and herbage height and between plots for chemical composition (P > 0.05). However, there were highly significant differences among periods (P < 0.01) for organic matter, neutral detergent fibre (NDF), acid detergent fibre, in vitro organic matter digestibility (IVOMD), and estimated metabolisable energy (eME), with highly significant plot × period interactions (P < 0.01) for NDF, IVOMD, and eME. There were no statistical differences (P > 0.05) between treatments for milk yield, chemical composition of milk, live weight, or body condition score. Post-experimental vegetation cover was 72 % for both stocking rates, indicating there was no degradation of the grassland. Lower feeding costs were for the low supplementation treatments. It is concluded that a high stocking rate in studied native grasslands of 4 cows/ha with moderate concentrate supplementation supports a mean milk yield of 11.9 kg/cow/day during the rainy season without deleterious effects on the grassland.

  12. Protocol for Automated Zooplankton Analysis

    DTIC Science & Technology

    2010-01-01

    on maximum dimension on the smallest axis: organisms > 50 microns (urn) (nominally zooplankton), organisms > 10 um to < 50 um (nominally protists ...viability of protists . Recent work has focused on performing measurements at a variety of geographic locations to demonstrate that these stains...provide a location-independent means to identify viable protists in test samples. NRL recommends staining samples with a combination of two vital stains

  13. Streambank response to simulated grazing

    Treesearch

    Warren P. Clary; John W. Kinney

    2000-01-01

    Simulated grazing techniques were used to investigate livestock impacts on structural characteristics of streambanks. The treatments consisted of no grazing, moderate early summer grazing, moderate mid summer grazing, and heavy season-long grazing. The heavy season-long treatment resulted in a 11.5 cm depression of the streambank surface, while the moderate treatments...

  14. Zooplankton community response to the winter 2013 deep convection process in the NW Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Donoso, Katty; Carlotti, François; Pagano, Marc; Hunt, Brian P. V.; Escribano, Rubén.; Berline, Léo.

    2017-03-01

    The Gulf of Lion is an important area of deep convection, where intense winter vertical mixing brings nutrients up from deeper layers, promoting the largest bloom in the Mediterranean at the end of winter/early spring. The DEWEX program conducted cruises in February and April 2013 to investigate the ecosystem level impacts of deep water convection. Zooplankton data were collected through net sampling and imaging with an Underwater Vision Profiler. In winter, low zooplankton abundance and biomass were observed in the Deep Convection Zone (DCZ) and higher values on its periphery. In spring, this pattern reversed with high biomass in the DCZ and lower values on the periphery. On average for the whole area, the potential grazing impact was estimated to increase by one order of magnitude from winter to spring. In April, all areas except the DCZ incurred top-down control by zooplankton on the phytoplankton stock. In the DCZ, the chlorophyll-a values remained high despite the high zooplankton biomass and carbon demand, indicating a sustained bottom-up control. The zooplankton community composition was comparable for both periods, typified by high copepod dominance, but with some differences between the DCZ and peripheral regions. In spring the DCZ was characterized by a strong increase in herbivorous species such as Centropages typicus and Calanus helgolandicus, and an increase in the number of large zooplankton individuals. Our study indicates that the DCZ is likely an area of both enhanced energy transfer to higher trophic levels and organic matter export in the North Western Mediterranean Sea.

  15. Grazing impact of the invasive clam Corbula amurensis on the microplankton assemblage of the northern San Francisco Estuary

    USGS Publications Warehouse

    Greene, Valerie E.; Sullivan, Lindsay J.; Thompson, Janet K.; Kimmerer, Wim J.

    2011-01-01

    Grazing by the overbite clam Corbula amurensis (formerly known as Potamocorbula) may be the cause of substantial declines in phytoplankton biomass and zooplankton in the San Francisco Estuary (SFE) following its introduction in 1986. While grazing rates have been examined on bacteria, phytoplankton, and copepod nauplii, the consumption of protistan microzooplankton by C. amurensis has not previously been measured. In this study, laboratory feeding experiments revealed that C. amurensis cleared 0.5 l ind-1 h-1 of microzooplankton (ciliates) and 0.2 l ind-1 h-1 of chlorophyll (chl) a. Despite the higher clearance rate on microzooplankton, clams obtained more of their carbon from phytoplankton, which dominated the prey assemblage on most dates. When the measured clearance rates are extrapolated to field populations of clams, fractional loss rates (50 to 90% d-1) exceed the population growth capacity of microzooplankton. Although microzooplankton may not be a major component of the diet of these clams, C. amurensis may further alter food web dynamics through consumption of this important trophic intermediary, thus disrupting this link from bacteria and phytoplankton to higher trophic levels.

  16. Grazing impact of the invasive clam Corbula amurensis on the microplankton assemblage of the northern San francisco estuary

    USGS Publications Warehouse

    Greene, V.E.; Sullivan, L.J.; Thompson, J.K.; Kimmerer, W.J.

    2011-01-01

    Grazing by the overbite clam Corbula amurensis (formerly known as Potamocorbula) may be the cause of substantial declines in phytoplankton biomass and zooplankton in the San Francisco Estuary (SFE) following its introduction in 1986. While grazing rates have been examined on bacteria, phytoplankton, and copepod nauplii, the consumption of protistan microzooplankton by C. amurensis has not previously been measured. In this study, laboratory feeding experiments revealed that C. amurensis cleared 0.5 l ind-1 h-1 of microzooplankton (ciliates) and 0.2 l ind-1 h-1 of chlorophyll (chl) a. Despite the higher clearance rate on microzooplankton, clams obtained more of their carbon from phytoplankton, which dominated the prey assemblage on most dates. When the measured clearance rates are extrapolated to field populations of clams, fractional loss rates (50 to 90% d-1) exceed the population growth capacity of microzooplankton. Although microzooplankton may not be a major component of the diet of these clams, C. amurensis may further alter food web dynamics through consumption of this important trophic intermediary, thus disrupting this link from bacteria and phytoplankton to higher trophic levels. ?? Inter-Research 2011.

  17. Livestock and elk grazing effects on stream morphology, brown trout population dynamics, movement, and growth rate, Valles Caldera National Preserve, New Mexico

    Treesearch

    Michael C. Anderson

    2009-01-01

    Ungulate grazing in riparian areas has been shown to detrimentally impact stream morphology and fish populations. Goals of this research were to assess changes in stream morphology and responses of a brown trout (Salmo trutta) population to exclusion of cattle (Bos taurus) and elk (Cervus elaphus) from riparian...

  18. Microscale nutrient patches produced by zooplankton

    PubMed Central

    Lehman, John T.; Scavia, Donald

    1982-01-01

    Both track autoradiography and grain-density autoradiography show that individual zooplankton create miniature patches of dissolved nutrients and that algae exploit those regions to absorb phosphate. The patches are short lived and can be dispersed artificially by small-scale turbulence. Our data support a simple model of encounters between algae and nutrient plumes produced by swimming zooplankton. PMID:16593218

  19. Zooplankton research off Peru: A review

    NASA Astrophysics Data System (ADS)

    Ayón, Patricia; Criales-Hernandez, Maria I.; Schwamborn, Ralf; Hirche, Hans-Jürgen

    2008-10-01

    A review of zooplankton studies conducted in Peruvian marine waters is given. After a short history of the development of zooplankton research off Peru, we review zooplankton methodology, taxonomy, biodiversity, spatial distribution, seasonal and interannual variability, trophodynamics, secondary production, and modelling. We review studies on several micro-, meso-, macro-, and meroplankton groups, and give a species list from both published and unpublished reports. Three regional zooplankton groups have been identified: (1) a continental shelf group dominated by Acartia tonsa and Centropages brachiatus; (2) a continental slope group characterized by siphonophores, bivalves, foraminifera and radiolaria; (3) and a species-rich oceanic group. The highest zooplankton abundances and biomasses were often found between 4-6°S and 14-16°S, where continental shelves are narrow. Species composition changes with distance from the shore. Species composition and biomass also vary strongly on short time scales due to advection, peaks of larval production, trophic interactions, and community succession. The relation of zooplankton to climatic variability (ENSO and multi-decadal) and fish stocks is discussed in the context of ecological regime shifts. An intermediate upwelling hypothesis is proposed, based on the negative effects of low upwelling intensity in summer or extremely strong and enduring winter upwelling on zooplankton abundance off Peru. According to this hypothesis, intermediate upwelling creates an optimal environmental window for zooplankton communities. Finally, we highlight important knowledge gaps that warrant attention in future.

  20. Acoustic Scattering Models of Zooplankton and Microstructure

    DTIC Science & Technology

    1997-09-30

    shelled (gastropods), and gas-bearing ( siphonophores )). 5) LABORATORY EXPERIMENTATION: ZOOPLANKTON. An extensive set of laboratory measurements on the...zooplankton ( siphonophores and pteropods) that have high enough target strengths and occur in sufficiently high numbers that they could interfere with

  1. Acoustic Scattering Models of Zooplankton and Microstructures

    DTIC Science & Technology

    1998-09-30

    scattering by the seafloor. SCATTERING BY GAS-BEARING ZOOPLANKTON. In earlier work we showed that the scattering by gas-bearing zooplankton ( siphonophores ... siphonophores and pteropods) that have high enough target strengths and occur in sufficiently high numbers that they could interfere with the performance of

  2. Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands

    Treesearch

    J.D. Reeder; G.E. Schuman

    2001-01-01

    We evaluated the effects of livestock grazing on C content of the plant-soil system (to 60 cm) of two semi-arid grasslands: a mixed-grass prairie (grazed 12 years), and a short-grass steppe (grazed 56 years). Grazing treatments included season-long grazing at heavy and light stocking rates, and non-grazed exclosures. Significantly higher soil C (0-30cm) was measured in...

  3. Dynamics of Marine Zooplankton: Social Behavior, Ecological Interactions, and Physically-Induced Variability

    DTIC Science & Technology

    2008-02-01

    97 3.3.2 Steady-state solutions ..... ........................ 100 3.4 Ecosystem dynamics ...... ............................. 102 3.4.1 Fast ...zooplankton motion is decoupled from biological ac- tivities, as calculated in Flier] et al. (1999). When the diffusion rate is fast compared to phytoplankton...homogenize the zooplankton distribution, which remains spatially more intermit - tent than a passive scalar field. The last panel shows the index for

  4. Steryl chlorin esters are formed by zooplankton herbivory

    NASA Astrophysics Data System (ADS)

    Harradine, Paul J.; Harris, Philip G.; Head, Robert N.; Harris, Roger P.; Maxwell, James R.

    1996-06-01

    Steryl chlorin esters (SCEs) were formed in laboratory feeding experiments when starved females of the copepod Calanus helgolandicus were allowed to graze on a culture of the diatom Thalassiosira weissflogii. They were found when the zooplankton had grazed for 48 hours and were also identified in fecal pellets subsequently left in seawater in the dark. The distribution contained the diatom sterols in approximately the same relative abundance as the free sterols in the substrate, as well as the most abundant copepod sterol, all esterified to the chlorophyll a degradation product, pyropheophorbide a. Hence, in studies aimed at using sedimentary SCE sterol distributions as indicators of phytoplankton community structure, cholesterol should not be considered since the cholesteryl ester of pyropheophorbide a was a significant component in the fecal pellet SCEs. The findings represent a step forward in unravelling the transformations undergone by chlorophyll a in aquatic environments, since the abundance and wide occurrence of sedimentary SCEs indicate that they are a significant preservational sink for the chlorophyll a biosynthesised in the photic zone.

  5. Feeding and production of zooplankton in the Catalan Sea (NW Mediterranean)

    NASA Astrophysics Data System (ADS)

    Saiz, Enric; Calbet, Albert; Atienza, Dacha; Alcaraz, Miquel

    2007-08-01

    Zooplankton are key components of the structure and functioning of marine planktonic food webs. They are the main link of planktonic primary production towards top pelagic consumer levels (fish), and play a relevant role on the nutrient recycling in the water column and on the export of particulate matter out of the photic zone. In this paper, we review the present knowledge on the feeding and production of zooplankton in the Catalan Sea (NW Mediterranean), with special emphasis on copepods. Feeding of zooplankton in the Catalan Sea appears typically food limited, with average daily rations on a yearly basis in the order of 48% body C d -1. Heterotrophic prey constitute a relevant fraction of their diet, as an alternative to the scarce phytoplankton in the area. From a structural point of view, the trophic impact and control of their prey populations are low on standing stocks but, at certain times, zooplankton can exert a meaningful effect on their prey production. Regarding zooplankton production, the available estimates of growth rates in the area are based on the egg production rate of copepods. Egg production rates appear to be limited, especially in summer. Tentative estimates of copepod production in the area are in the order of 20-40 mg C m -2 d -1. In conclusion, this review confirms that the oligotrophic character of the NW Mediterranean constrains the feeding activity and production of zooplankton.

  6. Avoidance of strobe lights by zooplankton

    USGS Publications Warehouse

    Hamel, Martin J.; Richards, Nathan S.; Brown, Michael L.; Chipps, Steven R.

    2010-01-01

    Underwater strobe lights can influence the behavior and distribution of fishes and are increasingly used as a technique to divert fish away from water intake structures on dams. However, few studies examine how strobe lights may affect organisms other than targeted species. To gain insight on strobe lighting effects on nontarget invertebrates, we investigated whether underwater strobe lights influence zooplankton distributions and abundance in Lake Oahe, South Dakota. Zooplankton were collected using vertical tows at 3 discrete distances from an underwater strobe light to quantify the influence of light intensity on zooplankton density. Samples were collected from 3 different depth ranges (0–10 m, 10–20 m and 20–30 m) at <1 m, 15 m and ⩾100 m distance intervals away from the strobe light. Copepods represented 67.2% and Daphnia spp. represented 23.3% of all zooplankton sampled from 17 August to 15 September 2004. Night time zooplankton densities significantly decreased in surface waters when strobe lights were activated. Copepods exhibited the greatest avoidance patterns, while Daphnia avoidance varied throughout sampling depths. These results indicate that zooplankton display negative phototaxic behavior to strobe lights and that researchers must be cognizant of potential effects to the ecosystem such as altering predator–prey interactions or affecting zooplankton distribution and growth.

  7. Impact of moderate silver carp biomass gradient on zooplankton communities in a eutrophic reservoir. Consequences for the use of silver carp in biomanipulation.

    PubMed

    Domaizon, I; Dévaux, J

    1999-07-01

    We examined the impacts of moderate gradient silver carp biomass (five levels from 0 to 36 g.m-3, i.e. about 0-792 kg.ha-1) on zooplankton communities of the eutrophic Villerest reservoir (France). During our mesocosm experiment changes in zooplankton assemblages were dependent on silver carp biomass. In the fishless and low fish biomass treatments, zooplankton abundance increased through time, owing to a peak in cladoceran density, but decreased (mainly cladocerans) at highest fish biomass. Copepods and rotifers were less affected at the highest fish biomass and dominated zooplankton communities. We highlighted that the presence of high silver carp biomass could lead to changes in phytoplankton assemblage via the impact on herbivorous zooplankton. Since silver carp efficiently graze on particles > 20 microns, the suppression of herbivorous cladocerans could result in an increase in small size algae (< 20 microns) abundance since these species would be released from grazers as well as competitors (large algae grazed by silver carp) and nutrients levels would be enhanced by fish internal loading. Our results showed that the use of low silver carp biomass (< 200 kg.ha-1) would allow us to minimize these negative effects.

  8. The effects of juvenile American shad planktivory on zooplankton production in Columbia River food webs

    USGS Publications Warehouse

    Haskell, Craig A.; Tiffan, Kenneth F.; Rondorf, Dennis W.

    2013-01-01

    Columbia River reservoirs support a large population of nonnative American Shad Alosa sapidissima that consume the zooplankton that native fishes also rely on. We hypothesized that the unprecedented biomass of juvenile American Shad in John Day Reservoir is capable of altering the zooplankton community if these fish consume a large portion of the zooplankton production. We derived taxon-specific estimates of zooplankton production using field data and a production model from the literature. Empirical daily ration was estimated for American Shad and expanded to population-level consumption using abundance and biomass data from hydroacoustic surveys. Daphnia spp. production was high in early summer but declined to near zero by September as shad abundance increased. American Shad sequentially consumed Daphnia spp., copepods, and Bosmina spp., which tracked the production trends of these taxa. American Shad evacuation rates ranged from 0.09 to 0.24/h, and daily rations ranged from 0.008 to 0.045 g·g−1·d−1 (dry weight) over all years. We observed peak American Shad biomass (45.2 kg/ha) in 1994, and daily consumption (1.6 kg/ha) approached 30% (5.3 kg/ha) of zooplankton production. On average, American Shad consumed 23.6% of the available zooplankton production (range, <1–83%). The changes in the zooplankton community are consistent with a top-down effect of planktivory by American Shad associated with their unprecedented biomass and consumption, but the effects are likely constrained by temperature, nutrient flux, and the seasonal production patterns of zooplankton in John Day Reservoir. American Shad add to the planktivory exerted by other species like Neomysis mercedis to reduce the capacity of the reservoir to support other planktivorous fishes. The introduction of American Shad and other nonnative species will continue to alter the food web in John Day Reservoir, potentially affecting native fishes, including Pacific salmon Oncorhynchus spp.

  9. Alfalfa weevil (Coleoptera:Curculionidae) management in alfalfa by spring grazing with cattle.

    PubMed

    Buntin, G D; Bouton, J H

    1996-12-01

    The effect of continuous, intensive grazing by cattle in the 1st alfalfa growth cycle on larval densities of the alfalfa weevil, Hyera postica (Gyllenhal), was evaluated in "Alfagraze' and "Apollo' alfalfa, which are tolerant and not tolerant to grazing, respectively. In small-cage exclusion trials, grazing reduced larval numbers in 1991 by 65% in Alfagraze and by 32% in Apollo. Larval numbers in 1992 were low (< or = 0.6 larvae per stem) and were not reduced significantly by grazing. Grazing and use of early insecticide treatments of permethrin or carbofuran at low rates with < or = 7-d grazing restrictions to suppress larval numbers before grazing also were examined in large-plot exclusion trails in 1993 and 1994. Grazing reduced larval densities by 60% in 1993 and 45% in 1994 during a 3-wk period beginning 3 wk after grazing was initiated. However, alfalfa weevil larvae caused moderate leaf injury in 1993 and severe injury in 1994 before grazing reduced larval numbers. Use of permethrin at 0.11 kg (AI)/ha or carbofuran or chlorpyrifos at 0.28 kg (AI)/ha effectively reduced larval numbers and prevented leaf injury before grazing began. Therefore, a combination of an early application of an insecticide treatment with a short grazing restriction followed by continuous grazing will control alfalfa weevil larvae while allowing cattle to graze and directly use forage of grazing-tolerant alfalfa.

  10. High evolutionary potential of marine zooplankton

    PubMed Central

    Peijnenburg, Katja T C A; Goetze, Erica

    2013-01-01

    Abstract Open ocean zooplankton often have been viewed as slowly evolving species that have limited capacity to respond adaptively to changing ocean conditions. Hence, attention has focused on the ecological responses of zooplankton to current global change, including range shifts and changing phenology. Here, we argue that zooplankton also are well poised for evolutionary responses to global change. We present theoretical arguments that suggest plankton species may respond rapidly to selection on mildly beneficial mutations due to exceptionally large population size, and consider the circumstantial evidence that supports our inference that selection may be particularly important for these species. We also review all primary population genetic studies of open ocean zooplankton and show that genetic isolation can be achieved at the scale of gyre systems in open ocean habitats (100s to 1000s of km). Furthermore, population genetic structure often varies across planktonic taxa, and appears to be linked to the particular ecological requirements of the organism. In combination, these characteristics should facilitate adaptive evolution to distinct oceanographic habitats in the plankton. We conclude that marine zooplankton may be capable of rapid evolutionary as well as ecological responses to changing ocean conditions, and discuss the implications of this view. We further suggest two priority areas for future research to test our hypothesis of high evolutionary potential in open ocean zooplankton, which will require (1) assessing how pervasive selection is in driving population divergence and (2) rigorously quantifying the spatial and temporal scales of population differentiation in the open ocean. Recent attention has focused on the ecological responses of open ocean zooplankton to current global change, including range shifts and changing phenology. Here, we argue that marine zooplankton also are well poised for evolutionary responses to global change. PMID:24567838

  11. Ingestion of Microplastics by Zooplankton in the Northeast Pacific Ocean.

    PubMed

    Desforges, Jean-Pierre W; Galbraith, Moira; Ross, Peter S

    2015-10-01

    Microplastics are increasingly recognized as being widespread in the world's oceans, but relatively little is known about ingestion by marine biota. In light of the potential for microplastic fibers and fragments to be taken up by small marine organisms, we examined plastic ingestion by two foundation species near the base of North Pacific marine food webs, the calanoid copepod Neocalanus cristatus and the euphausiid Euphausia pacifia. We developed an acid digestion method to assess plastic ingestion by individual zooplankton and detected microplastics in both species. Encounter rates resulting from ingestion were 1 particle/every 34 copepods and 1/every 17 euphausiids (euphausiids > copepods; p = 0.01). Consistent with differences in the size selection of food between these two zooplankton species, the ingested particle size was greater in euphausiids (816 ± 108 μm) than in copepods (556 ± 149 μm) (p = 0.014). The contribution of ingested microplastic fibres to total plastic decreased with distance from shore in euphausiids (r (2) = 70, p = 0.003), corresponding to patterns in our previous observations of microplastics in seawater samples from the same locations. This first evidence of microplastic ingestion by marine zooplankton indicate that species at lower trophic levels of the marine food web are mistaking plastic for food, which raises fundamental questions about potential risks to higher trophic level species. One concern is risk to salmon: We estimate that consumption of microplastic-containing zooplankton will lead to the ingestion of 2-7 microplastic particles/day by individual juvenile salmon in coastal British Columbia, and ≤91 microplastic particles/day in returning adults.

  12. Grazing effects on carbon fluxes in a northern China grassland

    USDA-ARS?s Scientific Manuscript database

    Grazing is a widespread use of grasslands in northern China, but if stocking rate exceeds grassland carrying capacity, degradation and desertification can occur. As a result, grazing management is critical and can play a significant role in driving C sink and source activity in grassland ecosystems...

  13. Grazing in central hardwood forests

    Treesearch

    Robert A. McQuilkin; Harold Scholten

    1989-01-01

    Woodland grazing is a major forestry and land management problem in parts of the central hardwood region. Most forest grazing is by cattle and, to a lesser extent, hogs in woodlands adjacent to pastures or feedlots. The practice is particularly common in the cattle producing areas of the Corn Belt where often 50 percent or more of the upland forest is grazed. Woodland...

  14. Grazing: the whole picture

    USDA-ARS?s Scientific Manuscript database

    Environmental concerns for our farms include nutrient leaching to ground water, runoff in surface water, gaseous emissions, and the carbon footprint of our production systems. Recent reports have labeled grazing-based dairies as less environmentally sustainable compared to year around confinement sy...

  15. Ingestion of microplastics by natural zooplankton groups in the northern South China Sea.

    PubMed

    Sun, Xiaoxia; Li, Qingjie; Zhu, Mingliang; Liang, Junhua; Zheng, Shan; Zhao, Yongfang

    2017-02-15

    The ingestion of microplastics by five natural zooplankton groups in the northern South China Sea was studied for the first time and two types of sampling nets (505μm and 160μm in mesh size) were compared. The microplastics were detected in zooplankton sampled from 16 stations, with the fibrous microplastics accounting for the largest proportion (70%). The main component of the found microplastics was polyester. The average length of the microplastics was 125μm and 167μm for Nets I and II, respectively. The encounter rates of microplastics/zooplankton increased with trophic levels. The average encounter rate of microplastics/zooplankton was 5%, 15%, 34%, 49%, and 120% for Net I, and 8%, 21%, 47%, 60%, and 143% for Net II for copepods, chaetognaths, jellyfish, shrimp, and fish larvae, respectively. The average abundance of microplastics that were ingested by zooplankton was 4.1pieces/m 3 for Net I and 131.5pieces/m 3 for Net II. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Prescribed grazing for management of invasive vegetation in a hardwood forest understory

    Treesearch

    Ronald A. Rathfon; Songlin Fei; Jason Tower; Kenneth Andries; Michael Neary

    2014-01-01

    Land managers considering prescribed grazing (PG) face a lack of information on animal stocking rates, timing of grazing, and duration of grazing to achieve desired conditions in natural ecosystems under invasion stress from a variety of nonnative invasive plant (NNIP) species. In this study we tested PG treatments using goats for reducing NNIP brush species and...

  17. Cow weights and calf production for pasture 12-C Lehmann lovegrass grazing trials, 1982 to 1993

    Treesearch

    Phil R. Ogden; E. Lamar Smith

    2003-01-01

    The purpose of the grazing trials described in this paper was to provide information to aid in the development of grazing management strategies where Lehmann lovegrass has become a dominant species. Seven pastures were utilized from 1984 to 1987 for a comparison of four yearlong stocking rates to seasonal grazing rotated through three pastures. A second trial, 1988 to...

  18. Bottom-up linkages between primary production, zooplankton, and fish in a shallow, hypereutrophic lake.

    PubMed

    Matsuzaki, Shin-Ichiro S; Suzuki, Kenta; Kadoya, Taku; Nakagawa, Megumi; Takamura, Noriko

    2018-06-09

    Nutrient supply is a key bottom-up control of phytoplankton primary production in lake ecosystems. Top-down control via grazing pressure by zooplankton also constrains primary production, and primary production may simultaneously affect zooplankton. Few studies have addressed these bidirectional interactions. We used convergent cross-mapping (CCM), a numerical test of causal associations, to quantify the presence and direction of the causal relationships among environmental variables (light availability, surface water temperature, NO 3 -N, and PO 4 -P), phytoplankton community composition, primary production, and the abundances of five functional zooplankton groups (large-cladocerans, small-cladocerans, rotifers, calanoids, and cyclopoids) in Lake Kasumigaura, a shallow, hypereutrophic lake in Japan. CCM suggested that primary production was causally influenced by NO 3 -N and phytoplankton community composition; there was no detectable evidence of a causal effect of zooplankton on primary production. Our results also suggest that rotifers and cyclopoids were forced by primary production, and cyclopoids were further influenced by rotifers. However, our CCM suggested that primary production was weakly influenced by rotifers (i.e., bidirectional interaction). These findings may suggest complex linkages between nutrients, primary production, and rotifers and cyclopoids, a pattern that has not been previously detected or has been neglected. We used linear regression analysis to examine the relationships between the zooplankton community and pond smelt (Hypomesus nipponensis), the most abundant planktivore and the most important commercial fish species in Lake Kasumigaura. The relative abundance of pond smelt was significantly and positively correlated with the abundances of rotifers and cyclopoids, which were causally influenced by primary production. This finding suggests that bottom-up linkages between nutrient, primary production, and zooplankton abundance might be a

  19. Seasonal variation of zooplankton abundance and community structure in Prince William Sound, Alaska, 2009-2016

    NASA Astrophysics Data System (ADS)

    McKinstry, Caitlin A. E.; Campbell, Robert W.

    2018-01-01

    , location, depth of chlorophyll-a max, mixed layer average salinity, chlorophyll-a maximum, and bottom depth (ρ = 0.24, p < 0.05). The disappearance of the summer community coincided with the appearance of the Gulf of Alaska warm water anomaly known as "The Blob". A shift in zooplankton community composition during critical grazing periods for predators such as juvenile Pacific herring (Clupea pallasi) could have energetic consequences for overwintering success.

  20. A new modelling approach for zooplankton behaviour

    NASA Astrophysics Data System (ADS)

    Keiyu, A. Y.; Yamazaki, H.; Strickler, J. R.

    We have developed a new simulation technique to model zooplankton behaviour. The approach utilizes neither the conventional artificial intelligence nor neural network methods. We have designed an adaptive behaviour network, which is similar to BEER [(1990) Intelligence as an adaptive behaviour: an experiment in computational neuroethology, Academic Press], based on observational studies of zooplankton behaviour. The proposed method is compared with non- "intelligent" models—random walk and correlated walk models—as well as observed behaviour in a laboratory tank. Although the network is simple, the model exhibits rich behavioural patterns similar to live copepods.

  1. Using dual-purpose crops in sheep-grazing systems.

    PubMed

    Dove, Hugh; Kirkegaard, John

    2014-05-01

    The utilisation of dual-purpose crops, especially wheat and canola grown for forage and grain production in sheep-grazing systems, is reviewed. When sown early and grazed in winter before stem elongation, later-maturing wheat and canola crops can be grazed with little impact on grain yield. Recent research has sought to develop crop- and grazing-management strategies for dual-purpose crops. Aspects examined have been grazing effects on crop growth, recovery and yield development along with an understanding of the grazing value of the crop fodder, its implications for animal nutrition and grazing management to maximise live-weight gain. By alleviating the winter 'feed gap', the increase in winter stocking rate afforded by grazing crops allows crop and livestock production to be increased simultaneously on the same farm. Integration of dual-purpose wheat with canola on mixed farms provides further systems advantages related to widened operational windows, weed and disease control and risk management. Dual-purpose crops are an innovation that has potential to assist in addressing the global food-security challenge. © 2013 Society of Chemical Industry.

  2. Acoustic Scattering Classification of Zooplankton and Microstructure

    DTIC Science & Technology

    2001-09-30

    As part of this investigation, we have been observing concentrations of siphonulae, a larval form of the gas-bearing zooplankton siphonophore . The...situ measurements of acoustic target strengths of siphonophores , a gas-bearing zooplankter,” ICES J. Mar. Sci. 58: 740-749. Warren, J.D., T.K

  3. Disentangling niche competition from grazing mortality in phytoplankton dilution experiments

    PubMed Central

    Weitz, Joshua S.

    2017-01-01

    The dilution method is the principal tool used to infer in situ microzooplankton grazing rates. However, grazing is the only mortality process considered in the theoretical model underlying the interpretation of dilution method experiments. Here we evaluate the robustness of mortality estimates inferred from dilution experiments when there is concurrent niche competition amongst phytoplankton. Using a combination of mathematical analysis and numerical simulations, we find that grazing rates may be overestimated—the degree of overestimation is related to the importance of niche competition relative to microzooplankton grazing. In response, we propose a conceptual method to disentangle the effects of niche competition and grazing by diluting out microzooplankton, but not phytoplankton. Our theoretical results suggest this revised “Z-dilution” method can robustly infer grazing mortality, regardless of the dominant phytoplankton mortality driver in our system. Further, we show it is possible to independently estimate both grazing mortality and niche competition if the classical and Z-dilution methods can be used in tandem. We discuss the significance of these results for quantifying phytoplankton mortality rates; and the feasibility of implementing the Z-dilution method in practice, whether in model systems or in complex communities with overlap in the size distributions of phytoplankton and microzooplankton. PMID:28505212

  4. Riparian Meadow Response to Modern Conservation Grazing Management

    NASA Astrophysics Data System (ADS)

    Oles, Kristin M.; Weixelman, Dave A.; Lile, David F.; Tate, Kenneth W.; Snell, Laura K.; Roche, Leslie M.

    2017-09-01

    Riparian meadows occupy a small proportion of the public lands in the western United States but they provide numerous ecosystem services, including the production of high-quality forage for livestock grazing. Modern conservation management strategies (e.g., reductions in livestock stocking rates and adoption of new riparian grazing standards) have been implemented to better balance riparian conservation and livestock production objectives on publicly managed lands. We examined potential relationships between long-term changes in plant community, livestock grazing pressure and environmental conditions at two spatial scales in meadows grazed under conservation management strategies. Changes in plant community were not associated with either livestock stocking rate or precipitation at the grazing allotment (i.e., administrative) scale. Alternatively, both grazing pressure and precipitation had significant, albeit modest, associations with changes in plant community at the meadow (i.e., ecological site) scale. These results suggest that reductions in stocking rate have improved the balance between riparian conservation and livestock production goals. However, associations between elevation, site wetness, precipitation, and changes in plant community suggest that changing climate conditions (e.g., reduced snowpack and changes in timing of snowmelt) could trigger shifts in plant communities, potentially impacting both conservation and agricultural services (e.g., livestock and forage production). Therefore, adaptive, site-specific management strategies are required to meet grazing pressure limits and safeguard ecosystem services within individual meadows, especially under more variable climate conditions.

  5. Riparian Meadow Response to Modern Conservation Grazing Management.

    PubMed

    Oles, Kristin M; Weixelman, Dave A; Lile, David F; Tate, Kenneth W; Snell, Laura K; Roche, Leslie M

    2017-09-01

    Riparian meadows occupy a small proportion of the public lands in the western United States but they provide numerous ecosystem services, including the production of high-quality forage for livestock grazing. Modern conservation management strategies (e.g., reductions in livestock stocking rates and adoption of new riparian grazing standards) have been implemented to better balance riparian conservation and livestock production objectives on publicly managed lands. We examined potential relationships between long-term changes in plant community, livestock grazing pressure and environmental conditions at two spatial scales in meadows grazed under conservation management strategies. Changes in plant community were not associated with either livestock stocking rate or precipitation at the grazing allotment (i.e., administrative) scale. Alternatively, both grazing pressure and precipitation had significant, albeit modest, associations with changes in plant community at the meadow (i.e., ecological site) scale. These results suggest that reductions in stocking rate have improved the balance between riparian conservation and livestock production goals. However, associations between elevation, site wetness, precipitation, and changes in plant community suggest that changing climate conditions (e.g., reduced snowpack and changes in timing of snowmelt) could trigger shifts in plant communities, potentially impacting both conservation and agricultural services (e.g., livestock and forage production). Therefore, adaptive, site-specific management strategies are required to meet grazing pressure limits and safeguard ecosystem services within individual meadows, especially under more variable climate conditions.

  6. Trophic transfer of microcystins through the lake pelagic food web: evidence for the role of zooplankton as a vector in fish contamination.

    PubMed

    Sotton, Benoît; Guillard, Jean; Anneville, Orlane; Maréchal, Marjorie; Savichtcheva, Olga; Domaizon, Isabelle

    2014-01-01

    An in situ study was performed to investigate the role of zooplankton as a vector of microcystins (MCs) from Planktothrix rubescens filaments to fish during a metalimnic bloom of P. rubescens in Lake Hallwil (Switzerland). The concentrations of MCs in P. rubescens and various zooplanktonic taxa (filter-feeders and predators) were assessed in different water strata (epi-, meta- and hypolimnion) using replicated sampling over a 24-hour survey. The presence of P. rubescens in the gut content of various zooplanktonic taxa (Daphnia, Bosmina and Chaoborus) was verified by targeting the cyanobacterial nucleic acids (DNA). These results highlighted that cyanobacterial cells constitute a part of food resource for herbivorous zooplanktonic taxa during metalimnic bloom periods. Furthermore, presence of MCs in Chaoborus larvae highlighted the trophic transfer of MCs between herbivorous zooplankton and their invertebrate predators. Our results suggest that zooplanktonic herbivores by diel vertical migration (DVM) act as vectors of MCs by encapsulating grazed cyanobacteria. As a consequence, they largely contribute to the contamination of zooplanktonic predators, and in fine of zooplanktivorous whitefish. Indeed, we estimated the relative contribution of three preys of the whitefish (i.e. Daphnia, Bosmina and Chaoborus) to diet contamination. We showed that Chaoborus and Daphnia were the highest contributor as MC vectors in the whitefish diet (74.6 and 20.5% of MC-LR equivalent concentrations, respectively). The transfer of MCs across the different trophic compartments follows complex trophic pathways involving various trophic levels whose relative importance in fish contamination might vary at daily and seasonal scale. © 2013.

  7. Aging of microplastics promotes their ingestion by marine zooplankton.

    PubMed

    Vroom, Renske J E; Koelmans, Albert A; Besseling, Ellen; Halsband, Claudia

    2017-12-01

    Microplastics (<5 mm) are ubiquitous in the marine environment and are ingested by zooplankton with possible negative effects on survival, feeding, and fecundity. The majority of laboratory studies has used new and pristine microplastics to test their impacts, while aging processes such as weathering and biofouling alter the characteristics of plastic particles in the marine environment. We investigated zooplankton ingestion of polystyrene beads (15 and 30 μm) and fragments (≤30 μm), and tested the hypothesis that microplastics previously exposed to marine conditions (aged) are ingested at higher rates than pristine microplastics. Polystyrene beads were aged by soaking in natural local seawater for three weeks. Three zooplankton taxa ingested microplastics, excluding the copepod Pseudocalanus spp., but the proportions of individuals ingesting plastic and the number of particles ingested were taxon and life stage specific and dependent on plastic size. All stages of Calanus finmarchicus ingested polystyrene fragments. Aged microbeads were preferred over pristine ones by females of Acartia longiremis as well as juvenile copepodites CV and adults of Calanus finmarchicus. The preference for aged microplastics may be attributed to the formation of a biofilm. Such a coating, made up of natural microbes, may contain similar prey as the copepods feed on in the water column and secrete chemical exudates that aid chemodetection and thus increase the attractiveness of the particles as food items. Much of the ingested plastic was, however, egested within a short time period (2-4 h) and the survival of adult Calanus females was not affected in an 11-day exposure. Negative effects of microplastics ingestion were thus limited. Our findings emphasize, however, that aging plays an important role in the transformation of microplastics at sea and ingestion by grazers, and should thus be considered in future microplastics ingestion studies and estimates of microplastics

  8. Nutrients, phytoplankton, zooplankton, and macrobenthos

    USGS Publications Warehouse

    Rudstam, Lars G.; Holeck, Kristen T.; Watkins, James M.; Hotaling, Christopher; Lantry, Jana R.; Bowen, Kelly L.; Munawar, Mohi; Weidel, Brian C.; Barbiero, Richard; Luckey, Frederick J.; Dove, Alice; Johnson, Timothy B.; Biesinger, Zy

    2017-01-01

    Lower trophic levels support the prey fish on which most sport fish depend. Therefore, understanding the production potential of lower trophic levels is integral to the management of Lake Ontario’s fishery resources. Lower trophic-level productivity differs among offshore and nearshore waters. In the offshore, there is concern about the ability of the lake to support Alewife (Table 1) production due to a perceived decline in productivity of phytoplankton and zooplankton whereas, in the nearshore, there is a concern about excessive attached algal production (e.g., Cladophora) associated with higher nutrient concentrations—the oligotrophication of the offshore and the eutrophication of the nearshore (Mills et al. 2003; Holeck et al. 2008; Dove 2009; Koops et al. 2015; Stewart et al. 2016). Even though the collapse of the Alewife population in Lake Huron in 2003 (and the associated decline in the Chinook Salmon fishery) may have been precipitated by a cold winter (Dunlop and Riley 2013), Alewife had not returned to high abundances in Lake Huron as of 2014 (Roseman et al. 2015). Failure of the Alewife population to recover from collapse has been attributed to declines in lower trophic-level production (Barbiero et al. 2011; Bunnell et al. 2014; but see He et al. 2015). In Lake Michigan, concerns of a similar Alewife collapse led to a decrease in the number of Chinook Salmon stocked. If lower trophic-level production declines in Lake Ontario, a similar management action could be considered. On the other hand, in Lake Erie, which supplies most of the water in Lake Ontario, eutrophication is increasing and so are harmful algal blooms. Thus, there is also a concern that nutrient levels and algal blooms could increase in Lake Ontario, especially in the nearshore. Solutions to the two processes of concern—eutrophication in the nearshore and oligotrophication in the offshore—may be mutually exclusive. In either circumstance, fisheries management needs information on

  9. Zooplankton diel vertical migration and contribution to deep active carbon flux in the NW Mediterranean

    NASA Astrophysics Data System (ADS)

    Isla, Alejandro; Scharek, Renate; Latasa, Mikel

    2015-03-01

    The diel vertical migration (DVM) of zooplankton contributes to the biological pump transporting material from surface to deep waters. We examined the DVM of the zooplankton community in different size fractions (53-200 μm, 200-500 μm, 500-1000 μm, 1000-2000 μm and > 2000 μm) during three cruises carried out in the open NW Mediterranean Sea. We assessed their metabolic rates from empirical published relationships and estimated the active fluxes of dissolved carbon to the mesopelagic zone driven by migrant zooplankton. Within the predominantly oligotrophic Mediterranean Sea, the NW region is one of the most productive ones, with a seasonal cycle characterized by a prominent spring bloom. The study area was visited at three different phases of the seasonal cycle: during the spring bloom, the post-bloom, and strongly stratified oligotrophic conditions. We found seasonal differences in DVM, less evident during the bloom. Changes in DVM intensity were related to the composition of the zooplanktonic assemblage, which also varied between cruises. Euphausiids appeared as the most active migrants in all seasons, and their life cycle conditioned the observed pattern. Immature stages, which are unable to perform large diel vertical movements, dominated during the bloom, in contrast to the higher relative importance of migrating adults in the other two sampling periods. The amount of dissolved carbon exported was determined by the migrant zooplankton biomass, being highest during the post-bloom (2.2 mmol C respired m- 2 d- 1, and up to 3.1 mmol C exported m- 2 d- 1 when DOC release estimations are added). The active transport by diel migrants represented a substantial contribution to total carbon export to deep waters, especially under stratified oligotrophic conditions, revealing the importance of zooplankton in the biological pump operating in the study area.

  10. Grazing management options in meeting objectives of grazing experiments

    USDA-ARS?s Scientific Manuscript database

    Decisions on which grazing management option to use in grazing experiments can be critical in meeting research objectives and generating information for the scientific community or technologies that meets the needs of forage-based enterprises. It is necessary to have an understanding of animal per...

  11. UV radiation and freshwater zooplankton: damage, protection and recovery

    PubMed Central

    Rautio, Milla; Tartarotti, Barbara

    2011-01-01

    While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiological protection mechanism seems to be superior, and while several unexplained and contradictory patterns exist in zooplankton UVR ecology, recent increases in our understanding are consistent with UVR playing an important role for zooplankton. This review examines the variability in freshwater zooplankton responses to UVR, with a focus on crustacean zooplankton (Cladocera and Copepoda). We present an overview of UVR-induced damages, and the protection and recovery mechanisms freshwater zooplankton use when exposed to UVR. We review the current knowledge of UVR impact on freshwater zooplankton at species and community levels, and discuss briefly how global change over the last three decades has influenced the UVR milieu in lakes. PMID:21516254

  12. Copepod grazing on phytoplankton in the Pacific sector of the Antarctic Polar Front

    NASA Astrophysics Data System (ADS)

    Urban-Rich, Juanita; Dagg, Michael; Peterson, Jay

    Mesozooplankton abundance, community structure and copepod grazing on phytoplankton were examined during the austral spring 1997 and summer 1998 as part of the US JGOFS project in the Pacific sector of the Antarctic polar front. Mesozooplankton abundance and biomass were highest at the polar front and south of the front. Biomass increased by 1.5-2-times during the course of the study . Calanoides acutus, Calanus propinquus, C. simillimus, Rhincalanus gigas and Neocalanus tonsus were the dominant large copepods found in the study. Oithona spp and pteropods were numerically important components of the zooplankton community. The copepod and juvenile krill community consumed 1-7% of the daily chlorophyll standing stock, equivalent to 3-21% of the daily phytoplankton production. There was an increased grazing pressure at night due to both increased gut pigment concentrations as well as increases in zooplankton numbers. Phytoplankton carbon contributed a significant fraction (>50%) of the dietary carbon for the copepods during spring and summer. The relative importance of phytoplankton carbon to the diet increased south of the polar front, suggested that grazing by copepods could be important to organic carbon and biogenic silica flux south of the polar front.

  13. Trophic accumulation of PSP toxins in zooplankton during Alexandrium fundyense blooms in Casco Bay, Gulf of Maine, April-June 1998. II. . Zooplankton abundance and size-fractionated community composition

    NASA Astrophysics Data System (ADS)

    Turner, Jefferson T.; Doucette, Gregory J.; Keafer, Bruce A.; Anderson, Donald M.

    2005-09-01

    in size. Samples in the 100-200 μm size fraction were overwhelmingly dominated in most cases by copepod nauplii and small copepodites of O. similis, and during late May, rotifers. Samples in the 200-500 μm size fraction contained fewer copepod nauplii, but progressively more copepodites and adults of O. similis, particularly at offshore locations. At the most inshore stations, copepodites and adults of A. hudsonica were usual dominants. There were few copepod nauplii or O. similis in the>500 μm size fraction, which was usually dominated by copepodites and adults of C. finmarchicus, C. typicus, and Pseudocalanus spp. at offshore locations, and A. hudsonica inshore. Most of the higher PSP toxin concentrations were found in the larger zooplankton size fractions that were dominated by larger copepods such as C. finmarchicus and C. typicus. In contrast to our earlier findings, elevated toxin levels were also measured in numerous samples from smaller zooplankton size fractions, dominated by heterotrophic dinoflagellates, tintinnids and aloricate ciliates, rotifers, copepod nauplii, and smaller copepods such as O. similis and, at the most inshore locations, A. hudsonica. Thus, our data suggest that ingested PSP toxins are widespread throughout the zooplankton grazing community, and that potential vectors for intoxication of zooplankton assemblages include heterotrophic dinoflagellates, rotifers, protozoans, copepod nauplii, and small copepods.

  14. Grazing incidence relay optics

    NASA Technical Reports Server (NTRS)

    Chase, R. C.; Davis, J. M.; Krieger, A. S.; Underwood, J. H.

    1982-01-01

    The necessity to work in the focal plane of the primary mirrors has been one of the factors limiting the utility of grazing incidence telescopes in X-ray astronomy. In connection with the reported investigation, computer ray tracing programs have been used to study the performance of several grazing incidence relay optics (GIRO) systems used together with a large nested solar X-ray telescope. It was found that GIRO magnifiers are useful to map appropriate sized regions of the sun onto available CCD detectors. GIRO collimators can be used together with an X-ray spectrometer to study the X-ray spectrum from very small regions on the sun. Attention is given to the stationary mode, the tracking mode, and the size of GIRO elements. It is found that for a given GIRO size and magnification a use of the diverging system has the advantage of reducing the overall length of the main telescope-GIRO combination. However, the resolution provided by the diverging GIRO may not be as good as that obtained with the corresponding converging GIRO.

  15. Simulating rotational grazing management.

    PubMed

    Cros, M J; Duru, M; Garcia, F; Martin-Clouaire, R

    2001-09-01

    Dairy systems predominantly based on rotational grazing are notoriously hard to manage. In order to ensure profitability, this type of production requires quite good organisation, planning, and operating capability on the part of the farmer. A simulation-based decision support system, called SEPATOU, has been developed for this purpose. At the core of the decision support approach lies an explicit and rigorous modelling of the management strategy that underlies a dairy farmer's decision-making behaviour (real or hypothetical). The SEPATOU system is a discrete-event simulator that reproduces the day-to-day dynamics of the farmer's decision process and the response of the controlled biophysical system for which models of grass growth, animal consumption, and milk production are used. SEPATOU provides the means to evaluate and compare tentative strategies by simulating their application throughout the production season under different hypothetical weather conditions. The relative worth of a strategy can be assessed by analysing the effects on the biophysical system and their variability across the representative range of possible conditions that is considered. The activities to be managed concern the type and amount of conserved feed, where to fertilise and how much, the choice of fields to harvest, and most importantly, which field to graze next. Typically, SEPATOU is designed to be used by extension services and farming system scientists. It is implemented in C++ and is currently undergoing a validation process with the intended users.

  16. Grazing management for healthy watersheds

    Treesearch

    Karl Wood

    2008-01-01

    (Please note, this is an abstract only) New Mexico was historically grazed by many native and introduced ungulates, often called wildlife. Their distribution was limited especially in deserts until domestic animals were introduced and drinking water was provided. Plants respond to grazing with little resistance (black grama), to great resistance (blue grama), and to...

  17. Mob grazing for dairy cows

    USDA-ARS?s Scientific Manuscript database

    Proponents of mob grazing emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 lb/ac of beef cattle on small paddocks with rest periods up to 125 days. However, it is unclear if this management technique is appropriate for dair...

  18. Cattle Grazing in Delta Forests

    Treesearch

    Robert L. Johnson

    1960-01-01

    What effects do grazing cattle have on the hardwood forests of the Mississippi Delta? What is the value of the forage to the cattle? To answer such questions, grazing studies were conducted in 1957 on the Delta Experimental Forest, near Stoneville.

  19. Bivalve grazing can shape phytoplankton communities

    USGS Publications Warehouse

    Lucas, Lisa; Cloern, James E.; Thompson, Janet K.; Stacey, Mark T.; Koseff, Jeffrey K.

    2016-01-01

    The ability of bivalve filter feeders to limit phytoplankton biomass in shallow waters is well-documented, but the role of bivalves in shaping phytoplankton communities is not. The coupled effect of bivalve grazing at the sediment-water interface and sinking of phytoplankton cells to that bottom filtration zone could influence the relative biomass of sinking (diatoms) and non-sinking phytoplankton. Simulations with a pseudo-2D numerical model showed that benthic filter feeding can interact with sinking to alter diatom:non-diatom ratios. Cases with the smallest proportion of diatom biomass were those with the fastest sinking speeds and strongest bivalve grazing rates. Hydrodynamics modulated the coupled sinking-grazing influence on phytoplankton communities. For example, in simulations with persistent stratification, the non-sinking forms accumulated in the surface layer away from bottom grazers while the sinking forms dropped out of the surface layer toward bottom grazers. Tidal-scale stratification also influenced vertical gradients of the two groups in opposite ways. The model was applied to Suisun Bay, a low-salinity habitat of the San Francisco Bay system that was transformed by the introduction of the exotic clam Potamocorbula amurensis. Simulation results for this Bay were similar to (but more muted than) those for generic habitats, indicating that P. amurensis grazing could have caused a disproportionate loss of diatoms after its introduction. Our model simulations suggest bivalve grazing affects both phytoplankton biomass and community composition in shallow waters. We view these results as hypotheses to be tested with experiments and more complex modeling approaches.

  20. Nonlocal grazing in patterned ecosystems.

    PubMed

    Siero, E

    2018-01-07

    Many ecosystems exhibit gapped, labyrinthine, striped or spotted patterns. Important examples are vegetation patterns in drylands: these patterns are viewed as precursors of a catastrophic transition to a degraded state. A possible source of degradation is overgrazing, but many current spatially extended models include grazing in a local linear way. In this article nonlocal grazing responses are derived, taking into account (1) how many consumers there are (demographic response) (2) where they are (aggregative response) and (3) how much they forage (functional response). Different assumptions lead to different grazing responses, the type of grazing has a large influence on how ecosystems adapt to changing environmental conditions. In dryland simulations the different types of grazing are shown to alter the desertification process driven by decreasing rainfall. A sufficiently strong aggregative response leads to the suppression of vegetation patterns, nuancing their role as generic early warning signals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Acoustic Scattering Models of Zooplankton and Microstructure

    DTIC Science & Technology

    1999-09-30

    1998, a remotely operated vehicle was used to deploy acoustic transducers so that the acoustic scattering by siphonophores , a gas-bearing animal, could...their high frequency acoustics systems. 4) In addition, we have identified two types of zooplankton ( siphonophores and pteropods) that have high...Benfield, P.H. Wiebe, and D. Chu, 1999. “In situ measurements of acoustic target strengths of siphonophores ,” Proceedings of the 2nd EAA

  2. Woodlands Grazing Issues in Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Campos, P.

    2009-04-01

    's family ownerships. These poor livestockeepers could maintain their livestock regimen on the basis of low cash-income earnings and crops self-consumption in extremely poor family living conditions. In this state woodlands, social an environmental goals -as they were noted above- could generate high trade off between family basic needs and soil degradation because woodlands and crops operations. As result, grazing rent is pending on the low opportunity cost for family labour. In this context, Tunisian Mediterranean woodlands maintain the highest livestock rate population, which woodland economy could be called for poor people subsistence and environmentally unsustainable because soil erosion, forest degradation and over/under grazing. These study present three study cases where Mediterranean basin grazing resources economies are analyzed in the contexts of Tunisian developing economy (Iteimia woodlands, North West of Tunisia) and Spanish developed economy (Jerez de la Frontera and Monfragüe woodlands, South and West of Spain). The results show the crucial role that livestock (goat, sheep and cattle) play in maintaining the working Mediterranean woodlands landscape. People, woodlands and livestock grazing dependences are changing so fast in Mediterranean basin that they appear too complex for being accurately forecasting by rangeland economists. In this context, perhaps a question might be a more suitable concluding remark: ¿will does woodlands extensive livestock become a quasi-wild management for urban landowners pleasure aims in rich Mediterranean basin countries?

  3. Modelling the relationship between zooplankton biomass and environmental variations in the distribution of 210Po during a one year cycle in northwestern Mediterranean coastal waters.

    PubMed

    Färber Lorda, Jaime; Tateda, Yutaka; Fowler, Scott W

    2017-08-01

    To clarify the relationship between zooplankton biomass and the environmental kinetics of the natural radionuclide 210 Po during a one-year period (October 1995 to November 1996) in northwestern Mediterranean coastal waters, a modelling analysis was applied. Using 210 Po concentrations in seawater and zooplankton, the 210 Po uptake rate constant from food for zooplankton was evaluated using a biokinetics calculation involving the uptake and the excretion rate constants between seawater and zooplankton. Using the transfer constants obtained, the 210 Po concentrations in zooplankton were reconstructed and validated by observed concentrations. The simulation results were in good agreement with the measured 210 Po concentrations in zooplankton. Assuming that 210 Po fecal excretion represents the majority of the excretion of 210 Po from zooplankton, the fecal matter associated 210 Po vertical flux was calculated, and compared with the observed vertical fluxes of 210 Po measured in sediment traps. The modelling evaluation showed that fecal pellet vertical transport could not fully explain the observed sinking fluxes of particulate organic matter at 150 m depth, suggesting that other sinking biodetrital aggregates are also important components of the plankton-derived vertical flux of 210 Po. The relationship between 210 Po concentration in seawater and that in rain and dry fallout and their potential effect on 210 Po concentrations in zooplankton at this location were also examined. A similar, but diphased trend between 210 Po in zooplankton and 210 Po in rain and dry fallout deposition rate was demonstrated. 210 Po concentrations in the dissolved phase of seawater tended to diminish as mean daily rainfall increased suggesting that rain inputs serve as a 210 Po dilution mechanism in seawater at this location. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Effect of Grazing on Plant Attributes and Hydrological Properties in the Sloping Lands of the East African Highlands

    NASA Astrophysics Data System (ADS)

    Taddese, Girma; Saleem, M. A. Mohamed; Astatke, Abyie; Ayaleneh, Wagnew

    2002-09-01

    Extending livestock grazing to the steep slopes has led to unstable grazing systems in the East African Highlands, and new solutions and approaches are needed to ameliorate the current situation. This work was aimed at studying the effect of livestock grazing on plant attributes and hydrological properties. The study was conducted from 1996 to 2000 at the International Livestock Research Institute at Debre Ziet Research Station. Two sites were selected: one at 0-4% slope, and the other at 4-8% slope. The treatments were: (1) no grazing (control); (2) light grazing, 0.6 animal unit months per hectare (aum/ha); (3) moderate grazing, 1.8 aum/ha; (4) heavy grazing, 3.0 aum/ha; (5) very heavy grazing, 4.2 aum/ha; (6) initially plowed and continuously very heavily grazed, 4.2 aum/ha. The result showed that species richness, infiltration rate, bare ground, and soil loss significantly varied with grazing pressure. Species richness was higher in grazed plots compared to nongrazed plots. Biomass yield improved on heavily grazed plots as cow dung accumulated over years. Cynodon dactylon plant species persisted with livestock grazing pressure in both sites. Infiltration rate improved and soil erosion declined in all treatments after the first year.

  5. Grazing incidence beam expander

    NASA Astrophysics Data System (ADS)

    Akkapeddi, P. R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V. K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  6. Trophic pathways of phytoplankton size classes through the zooplankton food web over the spring transition period in the north-west Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Hunt, Brian P. V.; Carlotti, François; Donoso, Katty; Pagano, Marc; D'Ortenzio, Fabrizio; Taillandier, Vincent; Conan, Pascal

    2017-08-01

    Knowledge of the relative contributions of phytoplankton size classes to zooplankton biomass is necessary to understand food-web functioning and response to climate change. During the Deep Water formation Experiment (DEWEX), conducted in the north-west Mediterranean Sea in winter (February) and spring (April) of 2013, we investigated phytoplankton-zooplankton trophic links in contrasting oligotrophic and eutrophic conditions. Size fractionated particulate matter (pico-POM, nano-POM, and micro-POM) and zooplankton (64 to >4000 μm) composition and carbon and nitrogen stable isotope ratios were measured inside and outside the nutrient-rich deep convection zone in the central Liguro-Provencal basin. In winter, phytoplankton biomass was low (0.28 mg m-3) and evenly spread among picophytoplankton, nanophytoplankton, and microphytoplankton. Using an isotope mixing model, we estimated average contributions to zooplankton biomass by pico-POM, nano-POM, and micro-POM of 28, 59, and 15%, respectively. In spring, the nutrient poor region outside the convection zone had low phytoplankton biomass (0.58 mg m-3) and was dominated by pico/nanophytoplankton. Estimated average contributions to zooplankton biomass by pico-POM, nano-POM, and micro-POM were 64, 28 and 10%, respectively, although the model did not differentiate well between pico-POM and nano-POM in this region. In the deep convection zone, spring phytoplankton biomass was high (1.34 mg m-3) and dominated by micro/nano phytoplankton. Estimated average contributions to zooplankton biomass by pico-POM, nano-POM, and micro-POM were 42, 42, and 20%, respectively, indicating that a large part of the microphytoplankton biomass may have remained ungrazed.Plain Language SummaryThe <span class="hlt">grazing</span> of <span class="hlt">zooplankton</span> on algal phytoplankton is a critical step in the transfer of energy through all ocean food webs. Although microscopic, phytoplankton span an enormous size range. The smallest</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/5086','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/5086"><span>Effect of fertilizer applications and <span class="hlt">grazing</span> exclusion on species composition and biomass in wet meadow restoration in eastern Washington.</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John Beebe; Richard Everett; George Scherer; Carl. Davis</p> <p>2002-01-01</p> <p>Fertilizer applications and <span class="hlt">grazing</span> exclusion were used as restoration strategies in degraded wet meadows in eastern Washington to grow biomass in the root systems where it could not be <span class="hlt">grazed</span>. We used a split-block design to test vegetation responses to six fertilizer <span class="hlt">rates</span>, eight fertilizer types, and three <span class="hlt">grazing</span> treatments after three growing seasons. Little...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29531713','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29531713"><span>Improved protocols to accelerate the assembly of DNA barcode reference libraries for freshwater <span class="hlt">zooplankton</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Elías-Gutiérrez, Manuel; Valdez-Moreno, Martha; Topan, Janet; Young, Monica R; Cohuo-Colli, José Angel</p> <p>2018-03-01</p> <p>Currently, freshwater <span class="hlt">zooplankton</span> sampling and identification methodologies have remained virtually unchanged since they were first established in the beginning of the XX century. One major contributing factor to this slow progress is the limited success of modern genetic methodologies, such as DNA barcoding, in several of the main groups. This study demonstrates improved protocols which enable the rapid assessment of most animal taxa inhabiting any freshwater system by combining the use of light traps, careful fixation at low temperatures using ethanol, and <span class="hlt">zooplankton</span>-specific primers. We DNA-barcoded 2,136 specimens from a diverse array of taxonomic assemblages (rotifers, mollusks, mites, crustaceans, insects, and fishes) from several Canadian and Mexican lakes with an average sequence success <span class="hlt">rate</span> of 85.3%. In total, 325 Barcode Index Numbers (BINs) were detected with only three BINs (two cladocerans and one copepod) shared between Canada and Mexico, suggesting a much narrower distribution range of freshwater <span class="hlt">zooplankton</span> than previously thought. This study is the first to broadly explore the metazoan biodiversity of freshwater systems with DNA barcodes to construct a reference library that represents the first step for future programs which aim to monitor ecosystem health, track invasive species, or improve knowledge of the ecology and distribution of freshwater <span class="hlt">zooplankton</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSIS53A..02B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSIS53A..02B"><span>Determine Age-structure of Gelatinous <span class="hlt">Zooplankton</span> Using Optical Coherence Tomography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bi, H.; Shahrestani, S.; He, Y.</p> <p>2016-02-01</p> <p>Gelatinous are delicate and transparent by nature, but are conspicuous in many ecosystems when in bloom. Their proliferations are a bothersome and costly nuisance and influencing important food webs and species interactions. More importantly, gelatinous <span class="hlt">zooplankton</span> respond to climate change rapidly and understanding their upsurge needs information on their recruitment and population dynamics which in turn require their age-structure. However, ageing gelatinous <span class="hlt">zooplankton</span> is often restricted by the fact that they shrink under unfavorable conditions. In the present study, we examine the potential of using optical coherence tomography (OCT) to age gelatinous <span class="hlt">zooplankton</span>. OCT is a non-invasive imaging technique that uses light waves to examine 2D or 3D structure of target objects at a resolution of 3-5 µm. We were able to successfully capture both 3D and 2D images of sea nettle muscle fibers. Preliminary results on ctenophores will be discussed. Overall, this non-destructive sampling allows us to scan and capture images of mesoglea from jellyfish cultured in the lab, using the same individual repeatedly through time, documenting its growth which will provide precise measurements to construct an age key that will be applied to gelatinous <span class="hlt">zooplankton</span> captured in the field. Coupled with information on abundance, we can start to quantify their recruitment timing and success <span class="hlt">rate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PrOce.129..176M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PrOce.129..176M"><span>Bridging the gap between marine biogeochemical and fisheries sciences; configuring the <span class="hlt">zooplankton</span> link</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mitra, Aditee; Castellani, Claudia; Gentleman, Wendy C.; Jónasdóttir, Sigrún H.; Flynn, Kevin J.; Bode, Antonio; Halsband, Claudia; Kuhn, Penelope; Licandro, Priscilla; Agersted, Mette D.; Calbet, Albert; Lindeque, Penelope K.; Koppelmann, Rolf; Møller, Eva F.; Gislason, Astthor; Nielsen, Torkel Gissel; St. John, Michael</p> <p>2014-12-01</p> <p>Exploring climate and anthropogenic impacts on marine ecosystems requires an understanding of how trophic components interact. However, integrative end-to-end ecosystem studies (experimental and/or modelling) are rare. Experimental investigations often concentrate on a particular group or individual species within a trophic level, while tropho-dynamic field studies typically employ either a bottom-up approach concentrating on the phytoplankton community or a top-down approach concentrating on the fish community. Likewise the emphasis within modelling studies is usually placed upon phytoplankton-dominated biogeochemistry or on aspects of fisheries regulation. In consequence the roles of <span class="hlt">zooplankton</span> communities (protists and metazoans) linking phytoplankton and fish communities are typically under-represented if not (especially in fisheries models) ignored. Where represented in ecosystem models, <span class="hlt">zooplankton</span> are usually incorporated in an extremely simplistic fashion, using empirical descriptions merging various interacting physiological functions governing <span class="hlt">zooplankton</span> growth and development, and thence ignoring physiological feedback mechanisms. Here we demonstrate, within a modelled plankton food-web system, how trophic dynamics are sensitive to small changes in parameter values describing <span class="hlt">zooplankton</span> vital <span class="hlt">rates</span> and thus the importance of using appropriate <span class="hlt">zooplankton</span> descriptors. Through a comprehensive review, we reveal the mismatch between empirical understanding and modelling activities identifying important issues that warrant further experimental and modelling investigation. These include: food selectivity, kinetics of prey consumption and interactions with assimilation and growth, form of voided material, mortality <span class="hlt">rates</span> at different age-stages relative to prior nutrient history. In particular there is a need for dynamic data series in which predator and prey of known nutrient history are studied interacting under varied pH and temperature regimes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/30803','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/30803"><span>Livestock <span class="hlt">grazing</span> not detrimental to meadow wildflowers</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Raymond D. Ratliff</p> <p>1972-01-01</p> <p>Wildflower growth, meadow conditions, and <span class="hlt">grazing</span> methods were compared in the Bogard area, Lassen National Forest, northeastern California. The two <span class="hlt">grazing</span> methods were rest-rotation, in which range units are periodically rested from <span class="hlt">grazing</span>, and free-choice, in which range units are not provided any rest periods from use. The results suggest that <span class="hlt">grazing</span> per se need...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12362454','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12362454"><span>Profitability of <span class="hlt">grazing</span> versus mechanical forage harvesting on New York dairy farms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gloy, B A; Tauer, L W; Knoblauch, W</p> <p>2002-09-01</p> <p>The profitability of rotational <span class="hlt">grazing</span> versus mechanical harvesting of forages was estimated using data from 237 nongrazing and 57 <span class="hlt">grazing</span> farms participating in the New York farm business summary program in the year 2000. The objective was to perform an empirical comparison of the profitability of <span class="hlt">grazing</span> versus mechanical forage harvesting systems. A regression analysis technique that controls for treatment selection bias is used to determine the impact of <span class="hlt">grazing</span> on the <span class="hlt">rate</span> of return on assets. This is accomplished by joint maximum likelihood estimation of a probit adoption function and a profit function. The results indicate that treatment selection does not have an important impact on the estimate of the profitability of <span class="hlt">grazing</span>. There were wide ranges and overlap of profitability among herds using the two systems. However, other things equal, farmers utilizing <span class="hlt">grazing</span> systems were at least if not more profitable than farmers not using <span class="hlt">grazing</span> systems. After controlling for the factors influencing the decision to <span class="hlt">graze</span>, we found that herd size, <span class="hlt">rate</span> of milk production per cow, and prices received for milk have a strong positive impact on profitability. Farmers who perceive potential lifestyle benefits that might be obtained by implementing a <span class="hlt">grazing</span> system likely do not have to pay an income penalty for adopting a <span class="hlt">grazing</span> system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70162534','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70162534"><span>The impact of <span class="hlt">grazing</span> on plant fractal architecture and fitness of a mediterranean shrub (Anthyllis cytisoidesL.)</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Escos, J.; Alados, C.L.; Emlen, J.M.</p> <p>1997-01-01</p> <p>1. We examined natural <span class="hlt">grazing</span> by livestock (sheep and goats) on Albaida Anthyllis cytisoides L. with the aim of determining whether variation in the allometric relationships between plant parts provides a sensitive indicator of the impact of <span class="hlt">grazing</span>.2. The intra-individual variation in translatory symmetry with scale and increased complexity of fractal structures reflect environmental disturbance under heavy <span class="hlt">grazing</span> pressure and lack of <span class="hlt">grazing</span>.3. Fitness consequences of <span class="hlt">grazing</span> were also investigated. <span class="hlt">Grazing</span> promotes growth and adult survival, and a drop in seed production as a consequence of consumption. In spite of that, total inclusive fitness (population <span class="hlt">rate</span> of change) tends to increase with <span class="hlt">grazing</span>.4. Moderate <span class="hlt">grazing</span>, while promoting growth, also enhances stability of vegetative structures. The favourable effect of moderate levels of herbivory on A. cytisoides is reflected in the homeostatic maintenance of its translatory symmetry and in the increased complexity of its fractal structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28545095','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28545095"><span>Feeding on dispersed vs. aggregated particles: The effect of <span class="hlt">zooplankton</span> feeding behavior on vertical flux.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koski, Marja; Boutorh, Julia; de la Rocha, Christina</p> <p>2017-01-01</p> <p><span class="hlt">Zooplankton</span> feeding activity is hypothesized to attenuate the downward flux of elements in the ocean. We investigated whether the <span class="hlt">zooplankton</span> community composition could influence the flux attenuation, due to the differences of feeding modes (feeding on dispersed vs. aggregated particles) and of metabolic <span class="hlt">rates</span>. We fed 5 copepod species-three calanoid, one harpacticoid and one poecilamastoid-microplankton food, in either dispersed or aggregated form and measured <span class="hlt">rates</span> of respiration, fecal pellet production and egg production. Calanoid copepods were able to feed only on dispersed food; when their food was introduced as aggregates, their pellet production and respiration <span class="hlt">rates</span> decreased to <span class="hlt">rates</span> observed for starved individuals. In contrast, harpacticoids and the poecilamastoid copepod Oncaea spp. were able to feed only when the food was in the form of aggregates. The sum of copepod respiration, pellet production and egg production <span class="hlt">rates</span> was equivalent to a daily minimum carbon demand of ca. 10% body weight-1 for all non-feeding copepods; the carbon demand of calanoids feeding on dispersed food was 2-3 times greater, and the carbon demand of harpacticoids and Oncaea spp. feeding on aggregates was >7 times greater, than the resting <span class="hlt">rates</span>. The <span class="hlt">zooplankton</span> species composition combined with the type of available food strongly influences the calculated carbon demand of a copepod community, and thus also the attenuation of vertical carbon flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5435449','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5435449"><span>Feeding on dispersed vs. aggregated particles: The effect of <span class="hlt">zooplankton</span> feeding behavior on vertical flux</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Boutorh, Julia; de la Rocha, Christina</p> <p>2017-01-01</p> <p><span class="hlt">Zooplankton</span> feeding activity is hypothesized to attenuate the downward flux of elements in the ocean. We investigated whether the <span class="hlt">zooplankton</span> community composition could influence the flux attenuation, due to the differences of feeding modes (feeding on dispersed vs. aggregated particles) and of metabolic <span class="hlt">rates</span>. We fed 5 copepod species—three calanoid, one harpacticoid and one poecilamastoid–microplankton food, in either dispersed or aggregated form and measured <span class="hlt">rates</span> of respiration, fecal pellet production and egg production. Calanoid copepods were able to feed only on dispersed food; when their food was introduced as aggregates, their pellet production and respiration <span class="hlt">rates</span> decreased to <span class="hlt">rates</span> observed for starved individuals. In contrast, harpacticoids and the poecilamastoid copepod Oncaea spp. were able to feed only when the food was in the form of aggregates. The sum of copepod respiration, pellet production and egg production <span class="hlt">rates</span> was equivalent to a daily minimum carbon demand of ca. 10% body weight-1 for all non-feeding copepods; the carbon demand of calanoids feeding on dispersed food was 2–3 times greater, and the carbon demand of harpacticoids and Oncaea spp. feeding on aggregates was >7 times greater, than the resting <span class="hlt">rates</span>. The <span class="hlt">zooplankton</span> species composition combined with the type of available food strongly influences the calculated carbon demand of a copepod community, and thus also the attenuation of vertical carbon flux. PMID:28545095</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009DSRII..56.1882Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009DSRII..56.1882Z"><span>Upslope transport of near-bed <span class="hlt">zooplankton</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zimmer, Cheryl Ann</p> <p>2009-09-01</p> <p><span class="hlt">Zooplankton</span> residing just above the deep-sea floor is an important component of the benthic/benthopelagic food chain. Consuming planktonic particulates and organisms, holoplankton and meroplankton are prey for fish and large invertebrates. Mechanisms controlling their abundances have been explored over relatively long time scales (months to years). Here, <span class="hlt">zooplankton</span> were sampled every 2 h for 2.2 d using a moored, automated, serial <span class="hlt">zooplankton</span> pump. The physical regime (currents and temperature) 1-100 m above bottom was measured during an inclusive 24-d period. The study site was located on the upper continental slope (750 m) of the Mid-Atlantic Bight, between the productive shelf and more impoverished rise and abyss. The coupled biological and physical records indicated tidally driven, net upslope transport of the holoplankton. The copepod (74.5% of collections) time series showed marked periodicity with a peak frequency of ˜13 h, approximately the diurnal tide (Fourier analysis). Local maxima corresponded with minimal water temperatures. Moreover, tidal cross-slope flow was highly coherent and 90° out of phase with temperature. Thus, maximal copepod concentrations, originating in colder deeper water, would be transported up the slope by the tide. Estimated net displacement of ˜1 km/d would deliver the animals to continental-shelf depths within a couple weeks. Time series of the much less abundant larvaceans (urochordates) (15.3%) and polychaete larvae (8.9%) showed periodicities with peak frequencies of 8-9 h. Statistical significance of the periodic signals could not be determined due to low numbers. Revealing holoplankton dynamics on scales of hours, this study may contribute to understanding of, for example, copepod feeding and aggregation near the deep-sea floor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1008314','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1008314"><span>Fire and <span class="hlt">grazing</span> regulate belowground processes in tallgrass prairie</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Johnson, Loretta C.; Matchett, John R.</p> <p>2001-01-01</p> <p>In tallgrass prairie, belowground processes are even more important than in forested systems because aboveground biomass and standing dead litter are periodically removed by frequent fires or grazers. Thus, studies that address factors regulating belowground processes are especially relevant for tallgrass prairie. We predicted that effects of <span class="hlt">grazing</span> and burning differ belowground and that changes in root productivity caused by burning or <span class="hlt">grazing</span> provide feedback that affects ecosystem fluxes of C and N. These differences in belowground response should be driven largely by changes in N dynamics and the degree to which burning and <span class="hlt">grazing</span> affect the pathway and magnitude of N loss and the degree of N limitation in these systems. Fire, the major pathway of N loss in ungrazed tallgrass prairie, should result in reduced net N mineralization and N availability. We expected plants to compensate for increased N limitation by increasing their allocation to roots, as manifested in increased soil respiration and C cycling belowground. In contrast, <span class="hlt">grazing</span> conserves N in the ecosystem by redistributing the N once contained in grass to labile forms in urine and dung. Thus, we predicted that <span class="hlt">grazing</span> should increase N cycling <span class="hlt">rates</span> and N availability to plants. Consequently, <span class="hlt">grazed</span> plants should be less N limited and should allocate less C to roots and more to shoots. This, in turn, should decrease belowground C cycling, manifested as reduced soil CO2 flux.We explored the roles of <span class="hlt">grazing</span> and burning on root growth in experimental watersheds at Konza Prairie, Kansas, USA. To assess effects of fire on root productivity, we installed root ingrowth cores in two watersheds without grazers that differ in fire frequency: annually vs. infrequently burned (four years since the last fire). To assess effects of <span class="hlt">grazing</span>, we installed root ingrowth cores in an annually burned watershed <span class="hlt">grazed</span> by bison and in fenced controls (exclosures). Within bison “<span class="hlt">grazing</span> lawns,” root ingrowth cores</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/5910825','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/5910825"><span><span class="hlt">Grazing</span> incidence beam expander</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Akkapeddi, P.R.; Glenn, P.; Fuschetto, A.</p> <p>1985-01-01</p> <p>A <span class="hlt">Grazing</span> Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, wouldmore » allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=59616&keyword=opc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=59616&keyword=opc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span><span class="hlt">ZOOPLANKTON</span> SIZE-SPECTRA IN GREAT LAKES COASTAL WATERS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p><span class="hlt">Zooplankton</span> mean size and size-distribution are affected by planktivore pressure and potentially reflect the condition of trophic interactions and ecosystem health. We used an optical plankton counter (OPC) to survey and assess <span class="hlt">zooplankton</span> size-spectra for twenty locations in Lak...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=119024&keyword=opc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=119024&keyword=opc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>COMPARISONS OF <span class="hlt">ZOOPLANKTON</span> COMMUNITY SIZE STRUCTURE IN THE GREAT LAKES</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p><span class="hlt">Zooplankton</span> mean-size and size-spectra distribution potentially reflect the condition of trophic interactions and ecosystem health because they are affected by both resource availability and planktivore pressure. We assessed <span class="hlt">zooplankton</span> mean-size and size-spectra using an optical...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5627919','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5627919"><span>Indigenous species barcode database improves the identification of <span class="hlt">zooplankton</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yang, Jianghua; Zhang, Wanwan; Sun, Jingying; Xie, Yuwei; Zhang, Yimin; Burton, G. Allen; Yu, Hongxia</p> <p>2017-01-01</p> <p>Incompleteness and inaccuracy of DNA barcode databases is considered an important hindrance to the use of metabarcoding in biodiversity analysis of <span class="hlt">zooplankton</span> at the species-level. Species barcoding by Sanger sequencing is inefficient for organisms with small body sizes, such as <span class="hlt">zooplankton</span>. Here mitochondrial cytochrome c oxidase I (COI) fragment barcodes from 910 freshwater <span class="hlt">zooplankton</span> specimens (87 morphospecies) were recovered by a high-throughput sequencing platform, Ion Torrent PGM. Intraspecific divergence of most <span class="hlt">zooplanktons</span> was < 5%, except Branchionus leydign (Rotifer, 14.3%), Trichocerca elongate (Rotifer, 11.5%), Lecane bulla (Rotifer, 15.9%), Synchaeta oblonga (Rotifer, 5.95%) and Schmackeria forbesi (Copepod, 6.5%). Metabarcoding data of 28 environmental samples from Lake Tai were annotated by both an indigenous database and NCBI Genbank database. The indigenous database improved the taxonomic assignment of metabarcoding of <span class="hlt">zooplankton</span>. Most <span class="hlt">zooplankton</span> (81%) with barcode sequences in the indigenous database were identified by metabarcoding monitoring. Furthermore, the frequency and distribution of <span class="hlt">zooplankton</span> were also consistent between metabarcoding and morphology identification. Overall, the indigenous database improved the taxonomic assignment of <span class="hlt">zooplankton</span>. PMID:28977035</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1514090V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1514090V"><span>A New Trait-Based Auto-Emergent Model for <span class="hlt">Zooplankton</span> and Confrontation with Size-Structured Observations from the Bay of Biscay</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vandromme, Pieter; Sourisseau, Marc; Huret, Martin</p> <p>2013-04-01</p> <p><span class="hlt">Zooplankton</span> plays a significant role in marine ecosystems bridging the gap between primary producers and top consumers and interacting with the particle flux through complex dynamics. Scarcity of data and complexity of observing <span class="hlt">zooplankton</span> make it difficult to integrate it in biogeochemical models where it is most often formulated in a simpler manner, i.e. classic box models with usually two compartments (micro and meso/macro <span class="hlt">zooplankton</span>). Recent advances in automatic sizing, counting and identification allow better estimates of the dynamics and distribution of <span class="hlt">zooplankton</span>, notably through the measurement of its size structure, and for <span class="hlt">zooplankton</span> size matter. Most <span class="hlt">zooplankton</span> physiological <span class="hlt">rates</span> as well as predator:prey interactions can be significantly relied to individuals size through allometric relations. Such size-dependency was used in recent models. Yet, these models were neither confronted to observations nor integrated in 3D biogeochemical models. Here we propose a newly developed model of <span class="hlt">zooplankton</span> dynamics based on size-dependent allometric relations but which allows various diet types regardless of the size. A size and a degree of herbivory is randomly drawn for each <span class="hlt">zooplankton</span> species generated within the model (up to 400 here, limited by actual computational costs). By generating random degree of herbivory <span class="hlt">zooplankton</span> species of same size could have various diet (from herbivore to carnivore). Other parameters leading to various reproductive strategies or vertical migration could also be drawn randomly (not tested here). The <span class="hlt">zooplankton</span> model is coupled to the 3D biogeochemical model MARS3D on a test case representing a simplified view of the Bay of Biscay (i.e., continental shelf, estuary, tides). The model shows auto-emergent properties with the selection of size/diet most adapted to local conditions (here offshore vs. coastal, estuary…). Then, patterns of the modeled size-structure of the <span class="hlt">zooplankton</span> are confronted to the ones observed during</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.8683B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.8683B"><span>Indicators of <span class="hlt">grazing</span> impact in Inner Mongolian steppe ecosystems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blank, B.; Breuer, L.; Butterbach-Bahl, K.; Frede, H.-G.</p> <p>2009-04-01</p> <p>The DFG research group 536 MAGIM (Matter fluxes in grasslands of Inner Mongolia as influenced by stocking <span class="hlt">rate</span>) investigates the influence of <span class="hlt">grazing</span> intensity on matter and water cycles in <span class="hlt">grazed</span> steppe ecosystems of Inner Mongolia. This Sino-German co-operation applies an interdisciplinary approach to investigate major ecosystem functions and how they are affected by <span class="hlt">grazing</span> and overgrazing. Within the research group an indicator system is developed to systemize the feedback of ecosystem parameters to the influence of <span class="hlt">grazing</span> and to analyse, which parameter or parameter group reacts most sensitively. Parameters were measured at up to five different <span class="hlt">grazing</span> intensities (from ungrazed to heavy <span class="hlt">grazed</span>) and are related to four thematic indicator groups (plant productivity, atmosphere, pedosphere, hydrosphere). The parameters were scaled to allow assessing the influence of <span class="hlt">grazing</span> intensity between different sets of parameters. For this the average value of a parameter at the lowest <span class="hlt">grazing</span> intensity (ungrazed) was set 100%, so that the values at the other intensities could be scaled scaled adequately. Then the difference between highest and lowest <span class="hlt">grazing</span> intensity was determined. According to this difference the influence of <span class="hlt">grazing</span> was characterized as weak (< 20% difference), medium (20-40%), strong (40-60%) and very strong (> 60%). Impact of <span class="hlt">grazing</span> on the parameters will be marked as weak (w), medium (m), strong (s) and very strong (vs) in the text. The group plant productivity includes the vegetation parameters aboveground biomass and belowground biomass. Belowground biomass (s) was significantly different between <span class="hlt">grazing</span> treatments with the highest value at the ungrazed site (399.00 g m-2 a-1) and the lowest at the heavy <span class="hlt">grazed</span> site (208.00 g m-2 a-1). Aboveground biomass (m) ranged between 91.33-131.67 g m-2 a-1 and differed significantly between the ungrazed and the heavy <span class="hlt">grazed</span> site, again with higher values at the ungrazed site (Gao et al. 2008). The group</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000ECSS...50..129G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000ECSS...50..129G"><span><span class="hlt">Zooplankton</span> Distribution in Four Western Norwegian Fjords</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorsky, G.; Flood, P. R.; Youngbluth, M.; Picheral, M.; Grisoni, J.-M.</p> <p>2000-01-01</p> <p>A multi-instrumental array constructed in the Laboratoire d'Ecologie du Plancton Marin in Villefranche sur mer, France, named the Underwater Video Profiler (UVP), was used to investigate the vertical distribution of <span class="hlt">zooplankton</span> in four western Norwegian fjords in the summer 1996. Six distinct zoological groups were monitored. The fauna included: (a) small crustaceans (mainly copepods), (b) ctenophores (mainly lobates), (c) siphonophores (mainly physonects), (d) a scyphomedusa Periphylla periphylla, (e) chaetognaths and (f) appendicularians. The use of the non-disturbing video technique demonstrated that the distribution of large <span class="hlt">zooplankton</span> is heterogeneous vertically and geographically. Furthermore, the abundance of non-migrating filter feeders in the deep basins of the fjords indicates that there is enough food (living and non-living particulate organic matter) to support their dietary needs. This adaptation may be considered as a strategy for survival in fjords. Specifically, living in dark, deep water reduces visual predation and population loss encountered in the upper layer due to advective processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160008062','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160008062"><span><span class="hlt">Grazing</span> Incidence Optics Technology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ramsey, Brian; Smith, W. Scott; Gubarev, Mikhail; McCracken, Jeff</p> <p>2015-01-01</p> <p>This project is to demonstrate the capability to directly fabricate lightweight, high-resolution, <span class="hlt">grazing</span>-incidence x-ray optics using a commercially available robotic polishing machine. Typical x-ray optics production at NASA Marshall Space Flight Center (MSFC) uses a replication process in which metal mirrors are electroformed on to figured and polished mandrels from which they are later removed. The attraction of this process is that multiple copies can be made from a single master. The drawback is that the replication process limits the angular resolution that can be attained. By directly fabricating each shell, errors inherent in the replication process are removed. The principal challenge now becomes how to support the mirror shell during all aspects of fabrication, including the necessary metrology to converge on the required mirror performance specifications. This program makes use of a Zeeko seven-axis computer-controlled polishing machine (see fig. 1) and supporting fabrication, metrology, and test equipment at MSFC. The overall development plan calls for proof-of-concept demonstration with relatively thick mirror shells (5-6 mm, fig. 2) which are straightforward to support and then a transition to much thinner shells (2-3 mm), which are an order of magnitude thinner than those used for Chandra. Both glass and metal substrates are being investigated. Currently, a thick glass shell is being figured. This has enabled experience to be gained with programming and operating the polishing machine without worrying about shell distortions or breakage. It has also allowed time for more complex support mechanisms for figuring/ polishing and metrology to be designed for the more challenging thinner shells. These are now in fabrication. Figure 1: Zeeko polishing machine.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5749802','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5749802"><span>Bioenergetics modeling of the annual consumption of <span class="hlt">zooplankton</span> by pelagic fish feeding in the Northeast Atlantic</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Utne, Kjell Rong; Jansen, Teunis; Huse, Geir</p> <p>2018-01-01</p> <p>The present study uses bioenergetics modeling to estimate the annual consumption of the main <span class="hlt">zooplankton</span> groups by some of the most commercially important planktivorous fish stocks in the Northeast Atlantic, namely Norwegian spring-spawning (NSS) herring (Clupea harengus), blue whiting (Micromesistius poutassou) and NEA mackerel (Scomber scombrus). The data was obtained from scientific surveys in the main feeding area (Norwegian Sea) in the period 2005–2010. By incorporating novel information about ambient temperature, seasonal growth and changes in the diet from stomach content analyses, annual consumption of the different <span class="hlt">zooplankton</span> groups by pelagic fish is estimated. The present study estimates higher consumption estimates than previous studies for the three species and suggests that fish might have a greater impact on the <span class="hlt">zooplankton</span> community as foragers. This way, NEA mackerel, showing the highest daily consumption <span class="hlt">rates</span>, and NSS herring, annually consume around 10 times their total biomass, whereas blue whiting consume about 6 times their biomass in <span class="hlt">zooplankton</span>. The three species were estimated to consume an average of 135 million (M) tonnes of <span class="hlt">zooplankton</span> each year, consisting of 53–85 M tonnes of copepods, 20–32 M tonnes of krill, 8–42 M tonnes of appendicularians and 0.2–1.2 M tonnes of fish, depending on the year. For NSS herring and NEA mackerel the main prey groups are calanoids and appendicularians, showing a peak in consumption during June and June–July, respectively, and suggesting high potential for inter-specific feeding competition between these species. In contrast, blue whiting maintain a low consumption <span class="hlt">rate</span> from April to September, consuming mainly larger euphausiids. Our results suggest that the three species can coexist regardless of their high abundance, <span class="hlt">zooplankton</span> consumption <span class="hlt">rates</span> and overlapping diet. Accordingly, the species might have niche segregation, as they are species specific, showing annual and inter</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4907199','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4907199"><span>Evaluation of Daphnid <span class="hlt">Grazing</span> on Microscopic Zoosporic Fungi by Using Comparative Threshold Cycle Quantitative PCR</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Maier, Michelle A.; Uchii, Kimiko; Peterson, Tawnya D.</p> <p>2016-01-01</p> <p>ABSTRACT Lethal parasitism of large phytoplankton by chytrids (microscopic zoosporic fungi) may play an important role in organic matter and nutrient cycling in aquatic environments by shunting carbon away from hosts and into much smaller zoospores, which are more readily consumed by <span class="hlt">zooplankton</span>. This pathway provides a mechanism to more efficiently retain carbon within food webs and reduce export losses. However, challenges in accurate identification and quantification of chytrids have prevented a robust assessment of the relative importance of parasitism for carbon and energy flows within aquatic systems. The use of molecular techniques has greatly advanced our ability to detect small, nondescript microorganisms in aquatic environments in recent years, including chytrids. We used quantitative PCR (qPCR) to quantify the consumption of zoospores by Daphnia in laboratory experiments using a culture-based comparative threshold cycle (CT) method. We successfully quantified the reduction of zoospores in water samples during Daphnia <span class="hlt">grazing</span> and confirmed the presence of chytrid DNA inside the daphnid gut. We demonstrate that comparative CT qPCR is a robust and effective method to quantify zoospores and evaluate zoospore <span class="hlt">grazing</span> by <span class="hlt">zooplankton</span> and will aid in better understanding how chytrids contribute to organic matter cycling and trophic energy transfer within food webs. IMPORTANCE The study of aquatic fungi is often complicated by the fact that they possess complex life cycles that include a variety of morphological forms. Studies that rely on morphological characteristics to quantify the abundances of all stages of the fungal life cycle face the challenge of correctly identifying and enumerating the nondescript zoospores. These zoospores, however, provide an important trophic link between large colonial phytoplankton and <span class="hlt">zooplankton</span>: that is, once the carbon is liberated from phytoplankton into the parasitic zoospores, the latter are consumed by <span class="hlt">zooplankton</span> and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27107112','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27107112"><span>Evaluation of Daphnid <span class="hlt">Grazing</span> on Microscopic Zoosporic Fungi by Using Comparative Threshold Cycle Quantitative PCR.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maier, Michelle A; Uchii, Kimiko; Peterson, Tawnya D; Kagami, Maiko</p> <p>2016-07-01</p> <p>Lethal parasitism of large phytoplankton by chytrids (microscopic zoosporic fungi) may play an important role in organic matter and nutrient cycling in aquatic environments by shunting carbon away from hosts and into much smaller zoospores, which are more readily consumed by <span class="hlt">zooplankton</span>. This pathway provides a mechanism to more efficiently retain carbon within food webs and reduce export losses. However, challenges in accurate identification and quantification of chytrids have prevented a robust assessment of the relative importance of parasitism for carbon and energy flows within aquatic systems. The use of molecular techniques has greatly advanced our ability to detect small, nondescript microorganisms in aquatic environments in recent years, including chytrids. We used quantitative PCR (qPCR) to quantify the consumption of zoospores by Daphnia in laboratory experiments using a culture-based comparative threshold cycle (CT) method. We successfully quantified the reduction of zoospores in water samples during Daphnia <span class="hlt">grazing</span> and confirmed the presence of chytrid DNA inside the daphnid gut. We demonstrate that comparative CT qPCR is a robust and effective method to quantify zoospores and evaluate zoospore <span class="hlt">grazing</span> by <span class="hlt">zooplankton</span> and will aid in better understanding how chytrids contribute to organic matter cycling and trophic energy transfer within food webs. The study of aquatic fungi is often complicated by the fact that they possess complex life cycles that include a variety of morphological forms. Studies that rely on morphological characteristics to quantify the abundances of all stages of the fungal life cycle face the challenge of correctly identifying and enumerating the nondescript zoospores. These zoospores, however, provide an important trophic link between large colonial phytoplankton and <span class="hlt">zooplankton</span>: that is, once the carbon is liberated from phytoplankton into the parasitic zoospores, the latter are consumed by <span class="hlt">zooplankton</span> and carbon is retained in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatSR...510892C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatSR...510892C"><span>Improved <span class="hlt">grazing</span> management may increase soil carbon sequestration in temperate steppe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Wenqing; Huang, Ding; Liu, Nan; Zhang, Yingjun; Badgery, Warwick B.; Wang, Xiaoya; Shen, Yue</p> <p>2015-07-01</p> <p>Different <span class="hlt">grazing</span> strategies impact grassland plant production and may also regulate the soil carbon formation. For a site in semiarid temperate steppe, we studied the effect of combinations of rest, high and moderate <span class="hlt">grazing</span> pressure over three stages of the growing season, on the process involved in soil carbon sequestration. Results show that constant moderate <span class="hlt">grazing</span> (MMM) exhibited the highest root production and turnover accumulating the most soil carbon. While deferred <span class="hlt">grazing</span> (RHM and RMH) sequestered less soil carbon compared to MMM, they showed higher standing root mass, maintained a more desirable pasture composition, and had better ability to retain soil N. Constant high <span class="hlt">grazing</span> pressure (HHH) caused diminished above- and belowground plant production, more soil N losses and an unfavorable microbial environment and had reduced carbon input. Reducing <span class="hlt">grazing</span> pressure in the last <span class="hlt">grazing</span> stage (HHM) still had a negative impact on soil carbon. Regression analyses show that adjusting stocking <span class="hlt">rate</span> to ~5SE/ha with ~40% vegetation utilization <span class="hlt">rate</span> can get the most carbon accrual. Overall, the soil carbon sequestration in the temperate grassland is affected by the <span class="hlt">grazing</span> regime that is applied, and <span class="hlt">grazing</span> can be altered to improve soil carbon sequestration in the temperate steppe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26137980','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26137980"><span>Improved <span class="hlt">grazing</span> management may increase soil carbon sequestration in temperate steppe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Wenqing; Huang, Ding; Liu, Nan; Zhang, Yingjun; Badgery, Warwick B; Wang, Xiaoya; Shen, Yue</p> <p>2015-07-03</p> <p>Different <span class="hlt">grazing</span> strategies impact grassland plant production and may also regulate the soil carbon formation. For a site in semiarid temperate steppe, we studied the effect of combinations of rest, high and moderate <span class="hlt">grazing</span> pressure over three stages of the growing season, on the process involved in soil carbon sequestration. Results show that constant moderate <span class="hlt">grazing</span> (MMM) exhibited the highest root production and turnover accumulating the most soil carbon. While deferred <span class="hlt">grazing</span> (RHM and RMH) sequestered less soil carbon compared to MMM, they showed higher standing root mass, maintained a more desirable pasture composition, and had better ability to retain soil N. Constant high <span class="hlt">grazing</span> pressure (HHH) caused diminished above- and belowground plant production, more soil N losses and an unfavorable microbial environment and had reduced carbon input. Reducing <span class="hlt">grazing</span> pressure in the last <span class="hlt">grazing</span> stage (HHM) still had a negative impact on soil carbon. Regression analyses show that adjusting stocking <span class="hlt">rate</span> to ~5SE/ha with ~40% vegetation utilization <span class="hlt">rate</span> can get the most carbon accrual. Overall, the soil carbon sequestration in the temperate grassland is affected by the <span class="hlt">grazing</span> regime that is applied, and <span class="hlt">grazing</span> can be altered to improve soil carbon sequestration in the temperate steppe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70027296','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70027296"><span>Density and success of bird nests relative to <span class="hlt">grazing</span> on western Montana grasslands</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fondell, Thomas F.; Ball, I.J.</p> <p>2004-01-01</p> <p>Grassland birds are declining at a faster <span class="hlt">rate</span> than any other group of North American bird species. Livestock <span class="hlt">grazing</span> is the primary economic use of grasslands in the western United States, but the effects of this use on distribution and productivity of grassland birds are unclear. We examined nest density and success of ground-nesting birds on <span class="hlt">grazed</span> and ungrazed grasslands in western Montana. In comparison to <span class="hlt">grazed</span> plots, ungrazed plots had reduced forb cover, increased litter cover, increased litter depth, and increased visual obstruction readings (VOR) of vegetation. Nest density among 10 of 11 common bird species was most strongly correlated with VOR of plots, and greatest nest density for each species occurred where mean VOR of the plot was similar to mean VOR at nests. Additionally, all bird species were relatively consistent in their choice of VOR at nests despite substantial differences in VOR among plots. We suggest that birds selected plots based in part on availability of suitable nest sites and that variation in nest density relative to <span class="hlt">grazing</span> reflected the effect of <span class="hlt">grazing</span> on availability of nest sites. Nest success was similar between <span class="hlt">grazed</span> plots and ungrazed plots for two species but was lower for nests on <span class="hlt">grazed</span> plots than on ungrazed plots for two other species because of increased <span class="hlt">rates</span> of predation, trampling, or parasitism by brown-headed cowbirds (Molothrus ater). Other species nested almost exclusively on ungrazed plots (six species) or <span class="hlt">grazed</span> plots (one species), precluding evaluation of the effects of <span class="hlt">grazing</span> on nest success. We demonstrate that each species in a diverse suite of ground-nesting birds preferentially used certain habitats for nesting and that <span class="hlt">grazing</span> altered availability of preferred nesting habitats through changes in vegetation structure and plant species composition. We also show that <span class="hlt">grazing</span> directly or indirectly predisposed some bird species to increased nesting mortality. Management alternatives that avoid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1001041','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1001041"><span>Characterization of Lake Michigan coastal lakes using <span class="hlt">zooplankton</span> assemblages</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Whitman, Richard L.; Nevers, Meredith B.; Goodrich, Maria L.; Murphy, Paul C.; Davis, Bruce M.</p> <p>2004-01-01</p> <p><span class="hlt">Zooplankton</span> assemblages and water quality were examined bi-weekly from 17 April to 19 October 1998 in 11 northeastern Lake Michigan coastal lakes of similar origin but varied in trophic status and limnological condition. All lakes were within or adjacent to Sleeping Bear Dunes National Lakeshore, Michigan. <span class="hlt">Zooplankton</span> (principally microcrustaceans and rotifers) from triplicate Wisconsin net (80 I?m) vertical tows taken at each lake's deepest location were analyzed. Oxygen-temperature-pH-specific conductivity profiles and surface water quality were concurrently measured. Bray-Curtis similarity analysis showed small variations among sample replicates but large temporal differences. The potential use of <span class="hlt">zooplankton</span> communities for environmental lake comparisons was evaluated by means of BIOENV (Primer 5.1) and principal component analyses. <span class="hlt">Zooplankton</span> analyzed at the lowest identified taxonomic level yielded greatest sensitivity to limnological variation. Taxonomic and ecological aggregations of <span class="hlt">zooplankton</span> data performed comparably, but less well than the finest taxonomic analysis. Secchi depth, chlorophyll a, and sulfate concentrations combined to give the best correlation with patterns of variation in the <span class="hlt">zooplankton</span> data set. Principal component analysis of these variables revealed trophic status as the most influential major limnological gradient among the study lakes. Overall, <span class="hlt">zooplankton</span> abundance was an excellent indicator of variation in trophic status.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.water.ca.gov/iep/newsletters/2005/IEPNewsletter_fall_2004_winter_2005.pdf','USGSPUBS'); return false;" href="http://www.water.ca.gov/iep/newsletters/2005/IEPNewsletter_fall_2004_winter_2005.pdf"><span>Preliminary results from a shallow water benthic <span class="hlt">grazing</span> study</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jones, N.L.; Monismith, Stephen G.; Thompson, Janet K.</p> <p>2005-01-01</p> <p>Despite great improvements in our knowledge on the effects of benthic grazers on seston concentrations in water columns, the effects of different hydrodynamic conditions on <span class="hlt">grazing</span> <span class="hlt">rates</span> has not been formulated. This makes it difficult to assess the system-wide effect of the benthic ecosystem on phytoplankton concentrations. Furthermore, it affects our ability to predict the potential success of a benthic species, such as the invasive clams Corbicula fluminea and Potamocorbula amurensis. This paper presents the preliminary results of a control volume approach to elucidate the effect of different hydrodynamic conditions on the <span class="hlt">grazing</span> <span class="hlt">rates</span> of Corbicula fluminea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PrOce.134..330A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PrOce.134..330A"><span>Migrant biomass and respiratory carbon flux by <span class="hlt">zooplankton</span> and micronekton in the subtropical northeast Atlantic Ocean (Canary Islands)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ariza, A.; Garijo, J. C.; Landeira, J. M.; Bordes, F.; Hernández-León, S.</p> <p>2015-05-01</p> <p>Diel Vertical Migration (DVM) in marine ecosystems is performed by <span class="hlt">zooplankton</span> and micronekton, promoting a poorly accounted export of carbon to the deep ocean. Major efforts have been made to estimate carbon export due to gravitational flux and to a lesser extent, to migrant <span class="hlt">zooplankton</span>. However, migratory flux by micronekton has been largely neglected in this context, due to its time-consuming and difficult sampling. In this paper, we evaluated gravitational and migratory flux due to the respiration of <span class="hlt">zooplankton</span> and micronekton in the northeast subtropical Atlantic Ocean (Canary Islands). Migratory flux was addressed by calculating the biomass of migrating components and measuring the electron transfer system (ETS) activity in <span class="hlt">zooplankton</span> and dominant species representing micronekton (Euphausia gibboides, Sergia splendens and Lobianchia dofleini). Our results showed similar biomass in both components. The main taxa contributing to DVM within <span class="hlt">zooplankton</span> were juvenile euphausiids, whereas micronekton were mainly dominated by fish, followed by adult euphausiids and decapods. The contribution to respiratory flux of <span class="hlt">zooplankton</span> (3.4 ± 1.9 mg C m-2 d-1) was similar to that of micronekton (2.9 ± 1.0 mg C m-2 d-1). In summary, respiratory flux accounted for 53% (range 23-71) of the gravitational flux measured at 150 m depth (11.9 ± 5.8 mg C m-2 d-1). However, based on larger migratory ranges and gut clearance <span class="hlt">rates</span>, micronekton are expected to be the dominant component that contributes to carbon export in deeper waters. Micronekton estimates in this paper as well as those in existing literature, although variable due to regional differences and difficulties in calculating their biomass, suggest that carbon fluxes driven by this community are important for future models of the biological carbon pump.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24809348','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24809348"><span>Traditional cattle <span class="hlt">grazing</span> in a mosaic alkali landscape: effects on grassland biodiversity along a moisture gradient.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Török, Péter; Valkó, Orsolya; Deák, Balázs; Kelemen, András; Tóthmérész, Béla</p> <p>2014-01-01</p> <p>Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional <span class="hlt">grazing</span> management is a crucial issue in grassland conservation actions worldwide. Traditional <span class="hlt">grazing</span> with robust cattle breeds in low stocking <span class="hlt">rates</span> is considered to be especially useful to mimic natural <span class="hlt">grazing</span> regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle <span class="hlt">grazing</span> as a conservation action in a mosaic alkali landscape. We asked the following questions: (i) How does cattle <span class="hlt">grazing</span> affect species composition and diversity of the grasslands? (ii) What are the effects of <span class="hlt">grazing</span> on short-lived and perennial noxious species? (iii) Are there distinct effects of <span class="hlt">grazing</span> in dry-, mesophilous- and wet grassland types? Vegetation of fenced and <span class="hlt">grazed</span> plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands) was sampled from 2006-2009 in East-Hungary. We found higher diversity scores in <span class="hlt">grazed</span> plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their <span class="hlt">grazed</span> counterparts in the last year in every studied grassland type. We found an increasing effect of <span class="hlt">grazing</span> from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle <span class="hlt">grazing</span> is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable livestock type.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=275697','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=275697"><span>Effects of <span class="hlt">grazing</span> intensity and chemical seedhead suppression on steers <span class="hlt">grazing</span> tall fescue pastures</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>The first year of a 2 yr <span class="hlt">grazing</span> study was conducted to evaluate use of Chaparral™ to suppress reproductive growth in tall fescue <span class="hlt">grazed</span> with low and moderate <span class="hlt">grazing</span> intensities. Chaparral applications (0 and 2.0 oz/acre) and <span class="hlt">grazing</span> intensities were arranged as RCBD with three replications. Variab...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29883873','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29883873"><span>Modeling species richness and abundance of phytoplankton and <span class="hlt">zooplankton</span> in radioactively contaminated water bodies.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shuryak, Igor</p> <p>2018-06-05</p> <p>Water bodies polluted by the Mayak nuclear plant in Russia provide valuable information on multi-generation effects of radioactive contamination on freshwater organisms. For example, lake Karachay was probably the most radioactive lake in the world: its water contained ∼2 × 10 7 Bq/L of radionuclides and estimated dose <span class="hlt">rates</span> to plankton exceeded 5 Gy/h. We performed quantitative modeling of radiation effects on phytoplankton and <span class="hlt">zooplankton</span> species richness and abundance in Mayak-contaminated water bodies. Due to collinearity between radioactive contamination, water body size and salinity, we combined these variables into one (called HabitatFactors). We employed a customized machine learning approach, where synthetic noise variables acted as benchmarks of predictor performance. HabitatFactors was the only predictor that outperformed noise variables and, therefore, we used it for parametric modeling of plankton responses. Best-fit model predictions suggested 50% species richness reduction at HabitatFactors values corresponding to dose <span class="hlt">rates</span> of 10 4 -10 5  μGy/h for phytoplankton, and 10 3 -10 4  μGy/h for <span class="hlt">zooplankton</span>. Under conditions similar to those in lake Karachay, best-fit models predicted 81-98% species richness reductions for various taxa (Cyanobacteria, Bacillariophyta, Chlorophyta, Rotifera, Cladocera and Copepoda), ∼20-300-fold abundance reduction for total <span class="hlt">zooplankton</span>, but no abundance reduction for phytoplankton. Rotifera was the only taxon whose fractional abundance increased with contamination level, reaching 100% in lake Karachay, but Rotifera species richness declined with contamination level, as in other taxa. Under severe radioactive and chemical contamination, one species of Cyanobacteria (Geitlerinema amphibium) dominated phytoplankton, and rotifers from the genus Brachionus dominated <span class="hlt">zooplankton</span>. The modeling approaches proposed here are applicable to other radioecological data sets. The results provide quantitative information</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title50-vol6/pdf/CFR-2010-title50-vol6-sec35-9.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title50-vol6/pdf/CFR-2010-title50-vol6-sec35-9.pdf"><span>50 CFR 35.9 - Livestock <span class="hlt">grazing</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Livestock <span class="hlt">grazing</span>. 35.9 Section 35.9... NATIONAL WILDLIFE REFUGE SYSTEM WILDERNESS PRESERVATION AND MANAGEMENT General Rules § 35.9 Livestock <span class="hlt">grazing</span>. (a) The <span class="hlt">grazing</span> of livestock, where established prior to the date of legislation which designates...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/34479','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/34479"><span>Livestock <span class="hlt">grazing</span>, wildlife habitat, and rangeland values</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Paul R. Krausman; David E. Naugle; Michael R. Frisina; Rick Northrup; Vernon C. Bleich; William M. Block; Mark C. Wallace; Jeffrey D. Wright</p> <p>2009-01-01</p> <p>Livestock managers make and implement <span class="hlt">grazing</span> management decisions to achieve a variety of objectives including livestock production, sustainable <span class="hlt">grazing</span>, and wildlife habitat enhancement. Assessed values of <span class="hlt">grazing</span> lands and ranches are often based on aesthetics and wildlife habitat or recreational values, which can exceed agricultural values, thus providing...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JDE...255..265H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JDE...255..265H"><span>Global dynamics of <span class="hlt">zooplankton</span> and harmful algae in flowing habitats</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hsu, Sze-Bi; Wang, Feng-Bin; Zhao, Xiao-Qiang</p> <p></p> <p>This paper is devoted to the study of two advection-dispersion-reaction models arising from the dynamics of harmful algae and <span class="hlt">zooplankton</span> in flowing-water habitats where a main channel is coupled to a hydraulic storage zone, representing an ensemble of fringing coves on the shoreline. For the system modeling the dynamics of algae and their toxin that contains little limiting nutrient, we establish a threshold type result on the global attractivity in terms of the basic reproduction ratio for algae. For the model with <span class="hlt">zooplankton</span> that eat the algae and are inhibited by the toxin produced by algae, we show that there exists a coexistence steady state and the <span class="hlt">zooplankton</span> is uniformly persistent provided that two basic reproduction ratios for algae and <span class="hlt">zooplankton</span> are greater than unity.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/35629','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/35629"><span><span class="hlt">Grazing</span> effects on grassland ecosystems</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Linda L. Wallace; Mel I. Dyer</p> <p>1996-01-01</p> <p>In this study, we used a modified version of a meta-analysis (compilation and analysis of the literature in which an individual area is subjected to the disturbance and its response is noted) to analyze <span class="hlt">grazing</span> effects on grassland ecosystems. Prior efforts have focused on one aspect of ecosystem behavior such as productivity or species diversity. In this analysis, we...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3720584','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3720584"><span>Phytoplankton Growth and Microzooplankton <span class="hlt">Grazing</span> in the Subtropical Northeast Atlantic</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cáceres, Carlos; Taboada, Fernando González; Höfer, Juan; Anadón, Ricardo</p> <p>2013-01-01</p> <p>Dilution experiments were performed to estimate phytoplankton growth and microzooplankton <span class="hlt">grazing</span> <span class="hlt">rates</span> during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2–5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and <span class="hlt">grazing</span> <span class="hlt">rates</span> between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth <span class="hlt">rates</span> were high (0.11–1.60 d−1), especially in the case of the large fraction. <span class="hlt">Grazing</span> <span class="hlt">rates</span> were also high (0.15–1.29 d−1), suggesting high turnover <span class="hlt">rates</span> within the phytoplankton community. The integrated balances between phytoplankton growth and <span class="hlt">grazing</span> losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres. PMID:23935946</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70156298','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70156298"><span>Seasonal cycles of <span class="hlt">zooplankton</span> from San Francisco Bay</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ambler, Julie W.; Cloern, James E.; Hutchinson, Anne</p> <p>1985-01-01</p> <p>Seasonal cycles of <span class="hlt">zooplankton</span> abundance appear to be constant among years (1978–1981) and are similar in the deep (>10 m) channels and lateral shoals (<3 m). The seasonal <span class="hlt">zooplankton</span> community dynamics are discussed in relation to: (1) river discharge which alters salinity distribution and residence time of plankton; (2) temperature which induces production and hatching of dormant copepod eggs; (3) coastal hydrography which brings neritic copepods of different zoogeographic affinities into the bay; and (4) seasonal cycles of phytoplankton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28912357','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28912357"><span><span class="hlt">Grazing</span> limits natural biological controls of woody encroachment in Inner Mongolia Steppe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guo, Hongyu; Guan, Linjing; Wang, Yinhua; Xie, Lina; Prather, Chelse M; Liu, Chunguang; Ma, Chengcang</p> <p>2017-10-15</p> <p>Woody encroachment in grasslands has become increasingly problematic globally. <span class="hlt">Grazing</span> by domestic animals can facilitate woody encroachment by reducing competition from herbaceous plants and fire frequency. Herbivorous insects and parasitic plants can each exert forces that result in the natural biological control of encroaching woody plants through reducing seeding of their host woody plants. However, the interplay of <span class="hlt">grazing</span> and dynamics of herbivorous insects or parasitic plants, and its effects on the potential biological control of woody encroachment in grasslands remains unclear. We investigated the flower and pod damage by herbivorous insects, and the infection <span class="hlt">rates</span> of a parasitic plant on the shrub Caragana microphylla , which is currently encroaching in Inner Mongolia Steppe, under different <span class="hlt">grazing</span> management treatments (33-year non-<span class="hlt">grazed</span>, 7-year non-<span class="hlt">grazed</span>, currently <span class="hlt">grazed</span>). Our results showed that Caragana biomass was highest at the currently <span class="hlt">grazed</span> site, and lowest at the 33-year non-<span class="hlt">grazed</span> site. Herbaceous plant biomass followed the opposite pattern, suggesting that <span class="hlt">grazing</span> is indeed facilitating the encroachment of Caragana plants in Inner Mongolia Steppe. <span class="hlt">Grazing</span> also reduced the abundance of herbivorous insects per Caragana flower, numbers of flowers and pods damaged by insect herbivores, and the infection <span class="hlt">rates</span> of the parasitic plant on Caragana plants. Our results suggest that <span class="hlt">grazing</span> may facilitate woody encroachment in grasslands not only through canonical mechanisms (e.g. competitive release via feeding on grasses, reductions in fires, etc.), but also by limiting natural biological controls of woody plants (herbivorous insects and parasitic plants). Thus, management efforts must focus on preventing overgrazing to better protect grassland ecosystems from woody encroachment. © 2017. Published by The Company of Biologists Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5665467','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5665467"><span><span class="hlt">Grazing</span> limits natural biological controls of woody encroachment in Inner Mongolia Steppe</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Guo, Hongyu; Guan, Linjing; Wang, Yinhua; Xie, Lina; Prather, Chelse M.; Liu, Chunguang</p> <p>2017-01-01</p> <p>ABSTRACT Woody encroachment in grasslands has become increasingly problematic globally. <span class="hlt">Grazing</span> by domestic animals can facilitate woody encroachment by reducing competition from herbaceous plants and fire frequency. Herbivorous insects and parasitic plants can each exert forces that result in the natural biological control of encroaching woody plants through reducing seeding of their host woody plants. However, the interplay of <span class="hlt">grazing</span> and dynamics of herbivorous insects or parasitic plants, and its effects on the potential biological control of woody encroachment in grasslands remains unclear. We investigated the flower and pod damage by herbivorous insects, and the infection <span class="hlt">rates</span> of a parasitic plant on the shrub Caragana microphylla, which is currently encroaching in Inner Mongolia Steppe, under different <span class="hlt">grazing</span> management treatments (33-year non-<span class="hlt">grazed</span>, 7-year non-<span class="hlt">grazed</span>, currently <span class="hlt">grazed</span>). Our results showed that Caragana biomass was highest at the currently <span class="hlt">grazed</span> site, and lowest at the 33-year non-<span class="hlt">grazed</span> site. Herbaceous plant biomass followed the opposite pattern, suggesting that <span class="hlt">grazing</span> is indeed facilitating the encroachment of Caragana plants in Inner Mongolia Steppe. <span class="hlt">Grazing</span> also reduced the abundance of herbivorous insects per Caragana flower, numbers of flowers and pods damaged by insect herbivores, and the infection <span class="hlt">rates</span> of the parasitic plant on Caragana plants. Our results suggest that <span class="hlt">grazing</span> may facilitate woody encroachment in grasslands not only through canonical mechanisms (e.g. competitive release via feeding on grasses, reductions in fires, etc.), but also by limiting natural biological controls of woody plants (herbivorous insects and parasitic plants). Thus, management efforts must focus on preventing overgrazing to better protect grassland ecosystems from woody encroachment. PMID:28912357</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26115251','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26115251"><span>FORAGES AND PASTURES SYMPOSIUM: Improving soil health and productivity on grasslands using managed <span class="hlt">grazing</span> of livestock.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Russell, J R; Bisinger, J J</p> <p>2015-06-01</p> <p>Beyond <span class="hlt">grazing</span>, managed grasslands provide ecological services that may offer economic incentives for multifunctional use. Increasing biodiversity of plant communities may maximize net primary production by optimizing utilization of available light, water, and nutrient resources; enhance production stability in response to climatic stress; reduce invasion of exotic species; increase soil OM; reduce nutrient leaching or loading in surface runoff; and provide wildlife habitat. Strategically managed <span class="hlt">grazing</span> may increase biodiversity of cool-season pastures by creating disturbance in plant communities through herbivory, treading, nutrient cycling, and plant seed dispersal. Soil OM will increase carbon and nutrient sequestration and water-holding capacity of soils and is greater in <span class="hlt">grazed</span> pastures than nongrazed grasslands or land used for row crop or hay production. However, results of studies evaluating the effects of different <span class="hlt">grazing</span> management systems on soil OM are limited and inconsistent. Although roots and organic residues of pasture forages create soil macropores that reduce soil compaction, <span class="hlt">grazing</span> has increased soil bulk density or penetration resistance regardless of stocking <span class="hlt">rates</span> or systems. But the effects of the duration of <span class="hlt">grazing</span> and rest periods on soil compaction need further evaluation. Because vegetative cover dissipates the energy of falling raindrops and plant stems and tillers reduce the <span class="hlt">rate</span> of surface water flow, managing <span class="hlt">grazing</span> to maintain adequate vegetative cover will minimize the effects of treading on water infiltration in both upland and riparian locations. Through increased diversity of the plant community with alterations of habitat structure, <span class="hlt">grazing</span> systems can be developed that enhance habitat for wildlife and insect pollinators. Although <span class="hlt">grazing</span> management may enhance the ecological services provided by grasslands, environmental responses are controlled by variations in climate, soil, landscape position, and plant community</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24467318','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24467318"><span>Cyanobacteria dominance influences resource use efficiency and community turnover in phytoplankton and <span class="hlt">zooplankton</span> communities.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Filstrup, Christopher T; Hillebrand, Helmut; Heathcote, Adam J; Harpole, W Stanley; Downing, John A</p> <p>2014-04-01</p> <p>Freshwater biodiversity loss potentially disrupts ecosystem services related to water quality and may negatively impact ecosystem functioning and temporal community turnover. We analysed a data set containing phytoplankton and <span class="hlt">zooplankton</span> community data from 131 lakes through 9 years in an agricultural region to test predictions that plankton communities with low biodiversity are less efficient in their use of limiting resources and display greater community turnover (measured as community dissimilarity). Phytoplankton resource use efficiency (RUE = biomass per unit resource) was negatively related to phytoplankton evenness (measured as Pielou's evenness), whereas <span class="hlt">zooplankton</span> RUE was positively related to phytoplankton evenness. Phytoplankton and <span class="hlt">zooplankton</span> RUE were high and low, respectively, when Cyanobacteria, especially Microcystis sp., dominated. Phytoplankton communities displayed slower community turnover <span class="hlt">rates</span> when dominated by few genera. Our findings, which counter findings of many terrestrial studies, suggest that Cyanobacteria dominance may play important roles in ecosystem functioning and community turnover in nutrient-enriched lakes. © 2014 John Wiley & Sons Ltd/CNRS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6698821-stable-isotope-analysis-zooplankton-samples-bowhead-whale-tissues-final-report','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6698821-stable-isotope-analysis-zooplankton-samples-bowhead-whale-tissues-final-report"><span>Stable isotope analysis of 1987-1991 <span class="hlt">zooplankton</span> samples and bowhead whale tissues. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schell, D.M.</p> <p>1992-06-01</p> <p>Stable isotope analyses of bowhead whale tissue samples and bowhead whale prey organisms collected over the years 1987 to 1991 were used to provide detail on the isotope ratio gradients evident in the arctic Alaskan <span class="hlt">zooplankton</span> and to verify previous findings regarding the growth <span class="hlt">rates</span> and age determination techniques developed for bowhead whales. <span class="hlt">Zooplankton</span> of the Bering and Chukchi seas are enriched in (13)C relative to the eastern Beaufort Sea. The analysis of baleen from bowhead whales taken between 1987 to 1990 indicate that the whales are slow-growing and the young animals between year one and about six to sevenmore » years of age, undergo a period of little or no linear growth. The authors estimate that bowheads require 16-18 years to reach the length of sexual maturity, i.e., 13-14 m. From baleen Delta(13C) cycles, a 20 year record of the isotope ratios in the phytoplankton of the northern Bering and Chukchi seas was constructed. The long-term record has been compared with the temperature anomalies in surface waters of the Bering Sea. The Delta(13C) of the <span class="hlt">zooplankton</span> is inversely correlated with temperature and refutes current models attempting to relate ocean temperature, and atmospheric carbon dioxide levels with the Delta(13C) of ocean sediment organic matter.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23033803','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23033803"><span>[Phytoplankton and <span class="hlt">zooplankton</span> of the industrial reservoir R-9 (Lake Karachay)].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Priakhin, E A; Triapitsina, G A; Atamaniuk, N I; Osipov, D I; Stukalov, P M; Ivanov, I A; Popova, I Ia; Akleev, A V</p> <p>2012-01-01</p> <p>Planktonic communities of the Reservoir-9 (Lake Karachay, storage reservoir of liquid medium-level radioactive waste of the Mayak Production Association) are exposed to the severe radioactive forcing (in 2010 the total beta-activity of the water was 1.8 x 10(7) Bq/L, total alpha-activity was 1.1 x 10(4) Bq/L), aswell as to the chemical contamination (level of nitrates in water 4.1 g/L). The calculated values of the absorbed dose <span class="hlt">rate</span> were 130 Gy/day for phytoplankton and 4.0 Gy/day for <span class="hlt">zooplankton</span>. Extremely low species diversity, the overwhelming dominance of one species (phytoplankton is close to a monoculture of ubiquitous cyanobacteria Geitlerinema amphibium, <span class="hlt">zooplankton</span>--to a monoculture of rotifers Hexarthrafennica), wide fluctuations in numbers of algae, a low number of <span class="hlt">zooplankton</span> were the most substantial characteristics of the plankton communities in Lake Karachay. So, plankton communities status is a sign of environmental retrogress in this ecosystem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22437379','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22437379"><span><span class="hlt">Zooplankton</span> community resilience and aquatic environmental stability on aquaculture practices: a study using net cages.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dias, J D; Simões, N R; Bonecker, C C</p> <p>2012-02-01</p> <p>Fish farming in net cages causes changes in environmental conditions. We evaluated the resilience of <span class="hlt">zooplankton</span> concerning this activity in Rosana Reservoir (Paranapanema River, PR-SP). Samples were taken near the net cages installed at distances upstream and downstream, before and after net cage installation. The resilience was estimated by the decrease in the groups' abundance after installing the net cages. The <span class="hlt">zooplankton</span> community was represented by 106 species. The most abundant species were Synchaeta pectinata, S. oblonga, Conochilus coenobasis, Polyarthra dolichoptera and C. unicornis (Rotifera), Ceriodaphnia cornuta, Moina minuta, Bosmina hagmanni and C. silvestrii (Cladocera) and Notodiaptomus amazonicus (Copepoda). The resilience of microcrustaceans was affected in the growing points as this activity left the production environment for longer, delaying the natural ability of community responses. Microcrustaceans groups, mainly calanoid and cyclopoid copepods, had a different return <span class="hlt">rate</span>. The net cage installation acted as a stress factor on the <span class="hlt">zooplankton</span> community. Management strategies that cause fewer risks to the organisms and maximize energy flow may help in maintaining system stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008DSRII..55.2285M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008DSRII..55.2285M"><span>Influence of spatial heterogeneity on the type of <span class="hlt">zooplankton</span> functional response: A study based on field observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morozov, Andrew; Arashkevich, Elena; Reigstad, Marit; Falk-Petersen, Stig</p> <p>2008-10-01</p> <p>Mathematical models of plankton dynamics are sensitive to the choice of type of <span class="hlt">zooplankton</span> functional response, i.e., to how the <span class="hlt">rate</span> of intake of food varies with the food density. Conventionally, the conclusion on the actual type of functional response for a given <span class="hlt">zooplankton</span> species is made based upon laboratory analysis on experimental feeding. In this paper, we show that such an approach can be too simplistic and misleading. Based on real ocean data obtained from three expeditions of R/V Jan Mayen in the Barents Sea in 2003-2005, we demonstrate that vertical heterogeneity in algal distribution as well as active vertical movement of herbivorous <span class="hlt">zooplankton</span> can modify the type of trophic response completely. In particular, we found that the <span class="hlt">rate</span> of average intake of algae by Calanus glacialis exhibits a Holling type III response, instead of Holling type I or II found previously in laboratory experiments. We argue that this conceptual discrepancy is due to the ability of the <span class="hlt">zooplankton</span> to feed in layers with high algal density and to avoid depths with lower algal density. Since theoretical studies would predict enhancing in system stability in the case of Holling type III, our results may be of importance for understanding the main factors controlling plankton dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=244074','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=244074"><span>Does livestock <span class="hlt">grazing</span> influence spatial patterns of woody plant proliferation?</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Patterns of woody plant proliferation in grasslands and savannas influence <span class="hlt">rates</span> of erosion, spread of disturbance, and nutrient pools.  Spatial pattern is the outcome of plant dispersal, recruitment, competition/facilitation, and disturbance. We quantified effects of livestock <span class="hlt">grazing</span>, a widely cit...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AcO....37..230A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AcO....37..230A"><span><span class="hlt">Grazing</span> effects on species composition in different vegetation types (La Palma, Canary Islands)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arévalo, J. R.; de Nascimento, L.; Fernández-Lugo, S.; Mata, J.; Bermejo, L.</p> <p>2011-05-01</p> <p><span class="hlt">Grazing</span> management is probably one of the most extensive land uses, but its effects on plant communities have in many cases been revealed to be contradictory. Some authors have related these contradictions to the stochastic character of <span class="hlt">grazing</span> systems. Because of that, it is necessary to implement specific analyses of <span class="hlt">grazing</span> effects on each community, especially in natural protected areas, in order to provide the best information to managers. We studied the effects of <span class="hlt">grazing</span> on the species composition of the main vegetation types where it takes place (grasslands, shrublands and pine forests) on the island of La Palma, Canary Islands. We used the point-quadrat intersect method to study the species composition of <span class="hlt">grazed</span> and ungrazed areas, which also were characterized by their altitude, distance to farms, distance to settlements, year of sampling, herbaceous aboveground biomass and soil organic matter. The variables organic matter, productivity and species richness were not significantly affected by <span class="hlt">grazing</span>. The species composition of the analyzed plant communities was affected more by variables such as altitude or distance to farms than by extensive <span class="hlt">grazing</span> that has been traditionally carried out on the island of La Palma involving certain practices such as continuous monitoring of animals by goat keepers, medium stocking <span class="hlt">rates</span> adjusted to the availability of natural pastures, supplementation during the dry season using local forage shrubs or mown pastures and rotating animals within <span class="hlt">grazing</span> areas Although some studies have shown a negative effect of <span class="hlt">grazing</span> on endangered plant species, these results cannot be freely extrapolated to the traditional <span class="hlt">grazing</span> systems that exert a low pressure on plant communities (as has been found in this study). We consider extensive <span class="hlt">grazing</span> as a viable way of ensuring sustainable management of the studied ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19657169','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19657169"><span>Pilot study on control of phytoplankton by <span class="hlt">zooplankton</span> coupling with filter-feeding fish in surface water.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Hua; Cui, Fuyi; Liu, Zhiquan; Fan, Zhenqiang</p> <p>2009-01-01</p> <p>A pilot-scale facility was originally designed to control phytoplankton in algae-laden reservoir water characterized by summer cyanobacteria blooms (mainly Microcystis flos-aquae). The system made good use of the different food habits of Daphnia magna and silver carp. <span class="hlt">Zooplankton</span> (Daphnia magna), filter-feeding fish (silver carp), and <span class="hlt">zooplankton</span> (Daphnia magna) were stocked in three separated tanks in sequence, respectively. Thus, single-cell phytoplankton and some Microcystis flos-aquae in small size were first <span class="hlt">grazed</span> by Daphnia magna in the first tank, and in the second tank phytoplankton larger than 10 microm were filtered by silver carp, and the concentration of the remaining phytoplankton was further reduced to a rather low level by Daphnia magna in the third tank. The results showed that the system had good removal efficiencies of phytoplankton and chlorophyll a, 86.85% and 59.41%, respectively, and permanganate consumption (COD(Mn)) and turbidity were lowered as well. A high phytoplankton removal efficiency and low cost indicated that the system had a good advantage in pre-treating algae-laden source water in drinking water works.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOS.B24A0323L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOS.B24A0323L"><span>Estimates of Gelatinous <span class="hlt">Zooplankton</span> Carbon Flux in the Global Oceans</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luo, J. Y.; Condon, R.; Cowen, R. K.</p> <p>2016-02-01</p> <p>Gelatinous <span class="hlt">zooplankton</span> (GZ), which include the cnidarians, ctenophores, and pelagic tunicates, are a common feature of marine ecosystems worldwide, but their contribution to global biogeochemical fluxes has never been assessed. We constructed a carbon-cycle model with a single, annual time-step and resolved to a 5° spatial grid for the three major GZ groups in order to evaluate the GZ-mediated carbon fluxes and export to depth. Biomass inputs (totaling 0.149 Pg C) were based off of Lucas et al. (2014) and updated using the JeDI database (Condon et al. 2015). From the upper ocean, biomass export flux from cnidarians, ctenophores, and tunicates totaled 2.96 ± 2.82 Pg C y-1, though only 0.199 ± 0.023 Pg C y-1 of GZ carbon were transferred to upper trophic levels, roughly amounting to one-quarter of all mesozooplankton production flux. In contrast, GZ fluxes to DOC only comprised ca. 2% of labile DOC flux. Egestion flux from the upper ocean totaled 2.56 ± 3.35 Pg C y-1, with over 80% being fast-sinking tunicate fecal pellets. Due to fast sinking <span class="hlt">rates</span> of carcasses and fecal pellets, 26% of all C export from the upper ocean reached the seafloor, such that GZ fecal matter is estimated to comprise between 20-30% of global POC surface export and 11-30% of POC seafloor deposition. Finally, results from sensitivity analyses showed no increase in cnidarian and ctenophore export fluxes with increased temperature and jelly biomass, though tunicate export fluxes showed some increase with both temperature and biomass. These results suggest that current estimates of global POC flux from the surface oceans, which range between 8.6 - 12.9 Pg C y-1, may be underestimated by as much as 20 - 25%, implying a definite need to incorporate GZ mediated flux in estimating the biological pump transfer efficiency. Our study represents the first effort to quantify the role of gelatinous <span class="hlt">zooplankton</span> in the global marine carbon cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28792594','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28792594"><span>A compilation of quantitative functional traits for marine and freshwater crustacean <span class="hlt">zooplankton</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hébert, Marie-Pier; Beisner, Beatrix E; Maranger, Roxane</p> <p>2016-04-01</p> <p>This data compilation synthesizes 8609 individual observations and ranges of 13 traits from 201 freshwater and 191 marine crustacean taxa belonging to either Copepoda or Cladocera, two important <span class="hlt">zooplankton</span> groups across all major aquatic habitats. Most data were gathered from the literature, with the balance being provided by <span class="hlt">zooplankton</span> ecologists. With the aim of more fully assessing <span class="hlt">zooplankton</span> effects on elemental processes such as nitrogen (N), phosphorus (P) and carbon (C) stocks and fluxes in aquatic ecosystems, this data set provides information on the following traits: body size (length and mass), trophic group, elemental and biochemical corporal composition (N, P, C, lipid and protein content), respiration <span class="hlt">rates</span>, N- and P-excretion <span class="hlt">rates</span>, as well as stoichiometric ratios. Although relationships for <span class="hlt">zooplankton</span> metabolism as a function of body mass or requirements have been explored in the past three decades, data have not been systematically compiled nor examined from an integrative and large-scale perspective across crustacean taxa and habitat types. While this contribution likely represents the most comprehensive assembly of traits for both marine and freshwater species, this data set is not exhaustive either. As a result, this compilation also identifies knowledge gaps: a fact that should encourage researchers to disclose information they may have to help complete such databases. This trait matrix is made available for the first time in this data paper; prior to its release, the data set has been analyzed in a meta-analysis published as a companion paper. This data set should prove extremely valuable for aquatic ecologists for trait-based characterization of plankton community structure as well as biogeochemical modeling. These data are also well-suited for deriving shortcut relationships that predict more difficult to measure trait values, most of which can be directly related to ecosystem properties (i.e., effect traits), from simpler traits (e</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME24B0709W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME24B0709W"><span>Can small <span class="hlt">zooplankton</span> enhance turbulence in a lake during vertical migration?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wain, D.; Simoncelli, S.; Thackeray, S.</p> <p>2016-02-01</p> <p>Recent research in both oceanic and freshwater systems suggests that the Diel Vertical Migration (DVM), a predator-avoidance mechanism adopted by many <span class="hlt">zooplankton</span>, may be an underrepresented source of turbulence and mixing. In particular, the migration can play a crucial role when organisms cross the thermocline; this could be particularly important in enhancing the mixing in lakes, where the pelagic zone is often quiescent, with a consequent impact on lake ecosystem functioning. A field experiment was performed to directly measure the temperature fluctuations and kinetic energy dissipation <span class="hlt">rate</span> generated by DVM of Daphnia spp., a 1 mm crustacean <span class="hlt">zooplankton</span> genus. Profiles of turbulence were acquired with a temperature microstructure profiler in Vobster Quay (UK), a small quarry with small wind fetch, steep sides, and with a maximum depth of approximately 25 m. Sixteen profiles were measured over the course of two hours during sunset on 16 July 2015, during which there was no wind. Backscatter strength from bottom-mounted ADCP was used as a proxy to assess DVM. <span class="hlt">Zooplankton</span> vertical distribution was also quantified by sampling with a 100 μm mesh net before and after the turbulence profiling in 8 layers to verify the distribution of Daphnia spp. before and after the migration. <span class="hlt">Zooplankton</span> tows show higher abundance (450 ind./L) of Daphnia at 9m and near the bottom before sunset (8PM). Samples after dusk (11.20PM) showed an increase in the surface layer, from 0 up to 250 ind./L. However, migration also appears to happen horizontally. Ensemble-averaged profiles show a great variation of the dissipation <span class="hlt">rates</span> over the course of the time series with a peak of 10-7 W/kg between 6m and 12m where the DVM is happening and with respect to profiles before sunset. Given the uncertainty in measuring the length scales of turbulence associated with small <span class="hlt">zooplankton</span>, further analysis is required to determine if the observed turbulence during the time of migration was due the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AcO....37...16P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AcO....37...16P"><span>The impact of cattle and goats <span class="hlt">grazing</span> on vegetation in oak stands of varying coppicing age</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Papachristou, Thomas G.; Platis, Panayiotis D.</p> <p>2011-01-01</p> <p> half of the herbaceous vegetation was removed through <span class="hlt">grazing</span> but it had no positive effect on the growth <span class="hlt">rate</span> of oak shoots. It seems that goats, which selected almost half of their diet from oak shoots, are responsible for that relative negative growth of shoots. However, cattle <span class="hlt">grazed</span> only herbs and may therefore control herbaceous vegetation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18214885','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18214885"><span>Determination of lead in samples of <span class="hlt">zooplankton</span>, water, and sediments in a Mexican reservoir: evidence for lead biomagnification in lower/intermediate trophic levels?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rubio-Franchini, Isidoro; Mejía Saavedra, Jesús; Rico-Martínez, Roberto</p> <p>2008-08-01</p> <p>We have determined lead concentration of water, sediment, and <span class="hlt">zooplankton</span> samples of El Niágara, a reservoir in Aguascalientes, Mexico. Our results include the first report of bioconcentration factor (BCF) obtained in an actual ecosystem (as opposed to the experimental setups in the laboratory) for a rotifer species; Asplanchna brigthwellii (BCF ca. 49 300). The BCF of this predatory <span class="hlt">zooplanktonic</span> species (A. brigthwellii) are up to four times greater than those of two <span class="hlt">grazing</span> <span class="hlt">zooplanktonic</span> species (Daphnia similis and Moina micrura). In this contaminated reservoir that lacks fishes, Asplanchna, and Culex sp. together with ducks and other bigger invertebrates might represent the top predators. Our data suggest that biomagnification of lead through at least one trophic level can occur in freshwater systems. Biomagnification in A. brigthwellii might be explained in part by predation of this voracious predator on young of the herbivorous cladoceran, M. micrura. Our findings stand opposite to the current theoretical framework where lead biomagnification occurs only in lower trophic levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080023333','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080023333"><span>Aberrations for <span class="hlt">Grazing</span> Incidence Optics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Saha, Timo T.</p> <p>2008-01-01</p> <p>Large number of <span class="hlt">grazing</span> incidence telescope configurations have been designed and studied. Wolte1 telescopes are commonly used in astronomical applications. Wolter telescopes consist of a paraboloidal primary mirror and a hyperboloidal or an ellipsoidal secondary mirror. There are 8 possible combinations of Wolter telescopes. Out of these possible designs only type 1 and type 2 telescopes are widely used. Type 1 telescope is typically used for x-ray applications and type 2 telescopes are used for EUV applications. Wolter-Schwarzshild (WS) telescopes offer improved image quality over a small field of view. The WS designs are stigmatic and free of third order coma and, therefore, the PSF is significantly better over a small field of view. Typically the image is more symmetric about its centroid. As for the Wolter telescopes there are 8 possible combinations of WS telescopes. These designs have not been widely used because the surface equations are complex parametric equations complicating the analysis and typically the resolution requirements are too low to take full advantage of the WS designs. There are several other design options. Most notable are wide field x-ray telescope designs. Polynomial designs were originally suggested by Burrows4 and hyperboloid-hyperboloid designs for solar physics applications were designed by Harvey5. No general aberration theory exists for <span class="hlt">grazing</span> incidence telescopes that would cover all the design options. Several authors have studied the aberrations of <span class="hlt">grazing</span> incidence telescopes. A comprehensive theory of Wolter type 1 and 2 telescopes has been developed. Later this theory was expanded to include all possible combinations of <span class="hlt">grazing</span> incidence and also normal incidence paraboloid-hyperboloid and paraboloid-ellipsoid telescopes. In this article the aberration theory of Wolter type telescopes is briefly reviewed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988SPIE..830..268G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988SPIE..830..268G"><span>Interferometry On <span class="hlt">Grazing</span> Incidence Optics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geary, Joseph; Maeda, Riki</p> <p>1988-08-01</p> <p>A preliminary interferometric procedure is described showing potential for obtaining surface figure error maps of <span class="hlt">grazing</span> incidence optics at normal incidence. The latter are found in some laser resonator configurations, and in Wolter type X-ray optics. The procedure makes use of cylindrical wavefronts and error subtraction techniques over subapertures. The surface error maps obtained will provide critical information to opticians in the fabrication process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987OptEn..26.1225G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987OptEn..26.1225G"><span>Interferometry on <span class="hlt">grazing</span> incidence optics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geary, Joseph M.; Maeda, Riki</p> <p>1987-12-01</p> <p>An interfeormetric procedure is described that shows potential for obtaining surface figure error maps of <span class="hlt">grazing</span> incidence optics at normal incidence. Such optics are found in some laser resonator configurations and in Wolter-type X-ray optics. The procedure makes use of cylindrical wavefronts and error subtraction techniques over subapertures. The surface error maps obtained will provide critical information to opticians for the fabrication process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870055440&hterms=REPLICATION&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DREPLICATION','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870055440&hterms=REPLICATION&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DREPLICATION"><span>Replication of <span class="hlt">grazing</span> incidence optics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ulmer, Melville P.</p> <p>1986-01-01</p> <p>The replication of <span class="hlt">grazing</span> incidence optics is reviewed. Electroform and epoxy replication are described and compared. It is concluded that for light weight and deep nesting, replication has a distinct advantage over direct production. The resolution of optics produced in this manner is however, limited to about 10 arc seconds; a typical value is 40 arc seconds. Epoxy replicated pieces tend to have better optical figures than electroformed optics, but the latter can be made thinner to make more deeply nested systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3918241','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3918241"><span>Carrion odor and cattle <span class="hlt">grazing</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lev-Yadun, Simcha; Gutman, Mario</p> <p>2013-01-01</p> <p>Recently, it has been proposed on theoretical grounds that carrion odor from flowers may not only attract pollinators, but also repel mammalian herbivores. Two <span class="hlt">grazing</span> experiments involving 16 to 26 cattle heads per year, one for eight years (1982–1989) and the other for seven (1994–2000), in a region with no large carnivores that could influence cattle behavior, show that cattle avoid areas where dead cattle have recently been dumped. They <span class="hlt">grazed</span> much less in these unfenced plots that were used to dump dead cattle each year. In the first experiment, with an area of ca. 20,000 m2 per head, the average grass biomass at the end of the season was 124.6 gr/m2 for the regular <span class="hlt">grazing</span> area, whereas it was 236.5 gr/m2 for the carcass dumping area. In the second experiment, with a higher stocking level, with ca. 9,000 m2 per head, the average grass biomass at the end of the season was 61.7 gr/m2 for the regular <span class="hlt">grazing</span> area, and 153.7 gr/m2 for the carcass dumping area. These significant differences existed throughout the 15 y of the experiments. We propose that these results are clear evidence of necrophobia in cattle, a character that might defend them from both pathogenic microbes and predators. This in turn demonstrates that carrion odor, primarily used by plants to attract pollinators, can simultaneously defend plants from herbivory by mammals as proposed. PMID:25210579</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/10179429','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/10179429"><span><span class="hlt">Zooplankton</span> data: Vertical distributions of <span class="hlt">zooplankton</span> in the Norweigian and Greenland Seas during summer, 1989</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lane, P.V.Z.; Smith, S.L.; Schwarting, E.M.</p> <p>1993-08-01</p> <p>Recent studies of <span class="hlt">zooplankton</span> populations in the Greenland Sea have focused on processes at the Marginal Ice Zone (MIZ) and the areas immediately adjacent to it under the ice and in open water. These studies have shown a relatively short period of intense secondary productivity which is closely linked temporally and spatially to phytoplankton blooms occurring near the ice edge in spring and early summer. During the summer of 1989 we participated in a project focusing on benthic and water column processes in the basins of the Norwegian and Greenland Seas. This study allowed us to compare biological processes atmore » the MIZ with those occurring in the open waters of the Greenland Sea, and to compare processes at both of these locations with those in the Norwegian Sea. The data presented in this report are the results of <span class="hlt">zooplankton</span> net tows covering the upper 1000 meters of the water column over the Norwegian Sea basin and the Greenland Sea basin, and the upper 500 meters of open water adjacent to the MIZ in the Greenland Sea. Sampling was conducted between 12 and 29 July 1989.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EnMan..54.1434L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EnMan..54.1434L"><span>Grassland Fire and Cattle <span class="hlt">Grazing</span> Regulate Reptile and Amphibian Assembly Among Patches</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Larson, Danelle M.</p> <p>2014-12-01</p> <p>Fire and <span class="hlt">grazing</span> are common management schemes of grasslands globally and are potential drivers of reptilian and amphibian (herpetofauna) metacommunity dynamics. Few studies have assessed the impacts of fire and cattle <span class="hlt">grazing</span> on herpetofauna assemblages in grasslands. A patch-burn <span class="hlt">grazing</span> study at Osage Prairie, MO, USA in 2011-2012 created landscape patches with treatments of <span class="hlt">grazing</span>, fire, and such legacies. Response variables were measured before and after the application of treatments, and I used robust-design occupancy modeling to estimate patch occupancy and detection <span class="hlt">rate</span> within patches, and recolonization and extinction (i.e., dispersal) across patches. I conducted redundancy analysis and a permuted multivariate analysis of variance to determine if patch type and the associated environmental factors explained herpetofauna assemblage. Estimates for reptiles indicate that occupancy was seasonally constant in Control patches ( ψ ~ 0.5), but declined to ψ ~ 0.15 in patches following the applications of fire and <span class="hlt">grazing</span>. Local extinctions for reptiles were higher in patches with fire or light <span class="hlt">grazing</span> ( ɛ ~ 0.7) compared to the controls. For the riparian herpetofaunal community, patch type and grass height were important predictors of abundance; further, the turtles, lizards, snakes, and adult amphibians used different patch types. The aquatic amphibian community was predicted by watershed and in-stream characteristics, irrespective of fire or <span class="hlt">grazing</span>. The varying responses from taxonomic groups demonstrate habitat partitioning across multiple patch types undergoing fire, cattle <span class="hlt">grazing</span>, and legacy effects. Prairies will need an array of patch types to accommodate multiple herpetofauna species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4492990','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4492990"><span>Estimating In Situ <span class="hlt">Zooplankton</span> Non-Predation Mortality in an Oligo-Mesotrophic Lake from Sediment Trap Data: Caveats and Reality Check</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dubovskaya, Olga P.; Tang, Kam W.; Gladyshev, Michail I.; Kirillin, Georgiy; Buseva, Zhanna; Kasprzak, Peter; Tolomeev, Aleksandr P.; Grossart, Hans-Peter</p> <p>2015-01-01</p> <p>Background Mortality is a main driver in <span class="hlt">zooplankton</span> population biology but it is poorly constrained in models that describe <span class="hlt">zooplankton</span> population dynamics, food web interactions and nutrient dynamics. Mortality due to non-predation factors is often ignored even though anecdotal evidence of non-predation mass mortality of <span class="hlt">zooplankton</span> has been reported repeatedly. One way to estimate non-predation mortality <span class="hlt">rate</span> is to measure the removal <span class="hlt">rate</span> of carcasses, for which sinking is the primary removal mechanism especially in quiescent shallow water bodies. Objectives and Results We used sediment traps to quantify in situ carcass sinking velocity and non-predation mortality <span class="hlt">rate</span> on eight consecutive days in 2013 for the cladoceran Bosmina longirostris in the oligo-mesotrophic Lake Stechlin; the outcomes were compared against estimates derived from in vitro carcass sinking velocity measurements and an empirical model correcting in vitro sinking velocity for turbulence resuspension and microbial decomposition of carcasses. Our results show that the latter two approaches produced unrealistically high mortality <span class="hlt">rates</span> of 0.58-1.04 d-1, whereas the sediment trap approach, when used properly, yielded a mortality <span class="hlt">rate</span> estimate of 0.015 d-1, which is more consistent with concurrent population abundance data and comparable to physiological death <span class="hlt">rate</span> from the literature. Ecological implications <span class="hlt">Zooplankton</span> carcasses may be exposed to water column microbes for days before entering the benthos; therefore, non-predation mortality affects not only <span class="hlt">zooplankton</span> population dynamics but also microbial and benthic food webs. This would be particularly important for carbon and nitrogen cycles in systems where recurring mid-summer decline of <span class="hlt">zooplankton</span> population due to non-predation mortality is observed. PMID:26146995</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23179900','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23179900"><span>Arbuscular mycorrhizal fungi associated with vegetation and soil parameters under rest <span class="hlt">grazing</span> management in a desert steppe ecosystem.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bai, Gegenbaoleer; Bao, Yuying; Du, Guoxin; Qi, Yunlong</p> <p>2013-05-01</p> <p>The impact of rest <span class="hlt">grazing</span> on arbuscular mycorrhizal fungi (AMF) and the interactions of AMF with vegetation and soil parameters under rest <span class="hlt">grazing</span> condition were investigated between spring and late summer in a desert steppe ecosystem with different <span class="hlt">grazing</span> managements (rest <span class="hlt">grazing</span> with different lengths of resting period, banned or continuous <span class="hlt">grazing</span>) in Inner Mongolia, China. AMF diversity and colonization, vegetation biomass, soil properties and soil phosphatase activity were examined. In rest <span class="hlt">grazing</span> areas of 60 days, AMF spore number and diversity index at a 0-10 cm soil depth as well as vesicular and hyphal colonization <span class="hlt">rates</span> were higher compared with other <span class="hlt">grazing</span> treatments. In addition, soil organic matter and total N contents were highest and soil alkaline phosphatase was most active under 60-day rest <span class="hlt">grazing</span>. In August and September, these areas also had the highest amount of aboveground vegetation. The results indicated that resting <span class="hlt">grazing</span> for an appropriate period of time in spring has a positive effect on AMF sporulation, colonization and diversity, and that under rest <span class="hlt">grazing</span> conditions, AMF parameters are positively correlated with some soil characteristics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ECSS..181..144F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ECSS..181..144F"><span>Potential retention effect at fish farms boosts <span class="hlt">zooplankton</span> abundance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernandez-Jover, D.; Toledo-Guedes, K.; Valero-Rodríguez, J. M.; Fernandez-Gonzalez, V.; Sanchez-Jerez, P.</p> <p>2016-11-01</p> <p>Coastal aquaculture activities influence wild macrofauna in natural environments due to the introduction of artificial structures, such as floating cages, that provide structural complexity in the pelagic system. This alters the abundance and distribution of the affected species and also their feeding behaviour and diet. Despite this, the effects of coastal aquaculture on <span class="hlt">zooplankton</span> assemblages and the potential changes in their abundance and distribution remain largely unstudied. Traditional plankton sampling hauls between the farm mooring systems entail some practical difficulties. As an alternative, light traps were deployed at 2 farms in the SW Mediterranean during a whole warm season. Total <span class="hlt">zooplankton</span> capture by traps at farms was higher than at control locations on every sampling night. It ranged from 3 to 10 times higher for the taxonomic groups: bivalvia, cladocera, cumacea, fish early-life-stages, gastropoda, polychaeta and tanaidacea; 10-20 times higher for amphipoda, chaetognatha, isopoda, mysidacea and ostracoda, and 22 times higher for copepoda and the crustacean juvenile stages zoea and megalopa. Permutational analysis showed significant differences for the most abundant <span class="hlt">zooplankton</span> groups (copepoda, crustacean larvae, chaetognatha, cladocera, mysidacea and polychaeta). This marked incremental increase in <span class="hlt">zooplankton</span> taxa at farms was consistent, irrespective of the changing environmental variables registered every night. Reasons for the greater abundance of <span class="hlt">zooplankton</span> at farms are discussed, although results suggest a retention effect caused by cage structures rather than active attraction through physical or chemical cues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPP24A0552B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPP24A0552B"><span>The Role of Cell Morphotype in Protist <span class="hlt">Grazing</span> on the Model Diatom Phaeodactylum tricornutum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaudoin, D.; Johnson, M. D.; Tirichine, L.; Rastogi, A.; Bowler, C.</p> <p>2016-02-01</p> <p>Microzooplankton <span class="hlt">grazing</span> is the single greatest loss to daily primary production in the oceans. Factors such as prey quality, chemical defense, and morphology are known to play important roles in mediating interactions with protist grazers. However, for most phytoplankton species we lack a mechanistic understanding of variables that modulate <span class="hlt">grazing</span> and their relative importance. Here we test the hypothesis that morphological complexity acts to decrease <span class="hlt">grazing</span> <span class="hlt">rates</span> of microzooplankton predators, using strains of Phaeodactylum tricornutum with distinct morphotypes (oval, fusiform, and triradiate). Specifically we expected to find lower <span class="hlt">grazing</span> on the triradiate morphotype. In experiments with predominantly uniform morphotypes, our results demonstrate that <span class="hlt">grazing</span> by the heterotrophic dinoflagellate Oxyrrhis marina was surprisingly greatest on triradiate P. tricornutum, while oval and fusiform morphotypes revealed lower <span class="hlt">rates</span>. Furthermore, the triradiate morphotype also supported higher growth <span class="hlt">rates</span> of O. marina. We are currently investigating the role of <span class="hlt">grazing</span> on morphotype frequency in P. tricornutum strains with mixed phenotypes. Chemical factors, such as prey nutritional content, and oxylipin profiles are also being investigated. Collectively, these experiments will help to determine the role of intraspecific phenotypes in predator-prey interactions, and how <span class="hlt">grazing</span> helps to shape morphotype frequency in prey populations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6894492-changes-fatty-acid-hydrocarbon-composition-zooplankton-assemblages-related-environmental-conditions','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6894492-changes-fatty-acid-hydrocarbon-composition-zooplankton-assemblages-related-environmental-conditions"><span>Changes in fatty acid and hydrocarbon composition of <span class="hlt">zooplankton</span> assemblages related to environmental conditions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lambert, R.M.</p> <p>1989-01-01</p> <p>Changes in <span class="hlt">zooplankton</span> fatty acid and hydrocarbon patterns are described in relation to changes in environmental conditions and species composition. The regulation of <span class="hlt">zooplankton</span> abundance by sea nettle-ctenophore interaction was examined in a small Rhode Island coastal pond. Sea nettles were nettles were able to eliminate ctenophores from the pond and subsequently <span class="hlt">zooplankton</span> abundance increased. During one increase in <span class="hlt">zooplankton</span> abundance, it was found that polyunsaturated fatty acids decreased while monounsaturated fatty acids increased. It was concluded that this shift in biochemical pattern was due to food limitation. In addition, <span class="hlt">zooplankton</span> fatty acids were used in multivariate discriminant analysis tomore » classify whether <span class="hlt">zooplankton</span> were from coastal or estuarine environments. <span class="hlt">Zooplankton</span> from coastal environments were characterized by higher monounsaturate fatty acids. <span class="hlt">Zooplankton</span> hydrocarbon composition was affected by species composition and by pollution inputs. The presence of Calanus finmarchicus was detected by increased levels of pristane.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/2871635','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/2871635"><span>Locomotor adaptations of some gelatinous <span class="hlt">zooplankton</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bone, Q</p> <p>1985-01-01</p> <p> cost of locomotion is greater in Doliolum. Few gelatinous <span class="hlt">zooplankton</span> show special adaptations both for rapid escape movements, and for slow sustained swimming, those that do deserve further study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987PrOce..19..353P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987PrOce..19..353P"><span>Interactions of phytoplankton, <span class="hlt">zooplankton</span> and microorganisms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pomeroy, L. R.; Paffenhöfer, G.-A.; Yoder, J. A.</p> <p></p> <p>We present evidence that there are significant interactions between heterotrophic microorganisms, doliolids and Fritillaria within intrusions of nutrient-rich Gulf Stream water stranding on the continental shelf. During the summer of 1981 cold, nutrient-rich water from below the surface of the Gulf Stream was repeatedly intruded and stranded on the continental shelf off northeastern Florida. On August 6 old, stranded Gulf Stream water depleted of nitrate occupied the lower layer on the outer shelf. The upper water was continental shelf water, older but of undefined age. On August 6 free-living bacteria were >10 6ml -1 everywhere at all depths, an order of magnitude greater than normal bacterial numbers on the northeastern Florida continental shelf. Over 10 days the numbers of free bacteria doubled while bacteria attached to particles increased by a factor of four. The adenylate/chlorophyll ratio showed that phytoplankton dominated the lower layers of intruded water, while the surface water became increasingly dominated by heterotrophic microorganisms (bacteria and protozoa) over 10 days. There were significant, negative correlations between bacteria and doliolids and between bacteria and Fritillaria. Regions of maximum bacterial numbers did not coincide with locations of salp swarms. The increased numbers of bacteria at all depths in a highly stratified system in which most phytoplankton are in the lower layer suggests a diverse source of bacterial growth substrates, some of which involve <span class="hlt">zooplankton</span> as intermediaries. Production of autotrophs is more than twice that of microheterotrophs on average, but because of their differential distribution, microheterotrophs are the dominant biomass in much of the surface water and may be significant in energy flux to metazoan consumers as well as competitors for mutually useable sources of nutrition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/961978','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/961978"><span>Lake Roosevelt Fisheries Evaluation Program, Part B; Limnology, Primary Production, and <span class="hlt">Zooplankton</span> in Lake Roosevelt, Washington, 1998 Annual Report.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shields, John; Spotts, Jim; Underwood, Keith</p> <p>2002-11-01</p> <p>The Lake Roosevelt Fisheries Evaluation Program is the result of a merger between two projects, the Lake Roosevelt Monitoring Program (BPA No. 8806300) and the Lake Roosevelt Data Collection Project (BPA No. 9404300). These projects were merged in 1996 to continue work historically completed under the separate projects, and is now referred to as the Lake Roosevelt Fisheries Evaluation Program. The 1998 Annual Report, Part B. Limnology, Primary Production, and <span class="hlt">Zooplankton</span> in Lake Roosevelt, Washington examined the limnology, primary production, and <span class="hlt">zooplankton</span> at eleven locations throughout the reservoir. The 1998 research protocol required a continuation of the more complete examinationmore » of limnological parameters in Lake Roosevelt that began in 1997. Phytoplankton and periphyton speciation, phytoplankton and periphyton chlorophyll a analysis, complete <span class="hlt">zooplankton</span> biomass analysis by taxonomic group, and an increased number of limnologic parameters (TDG, TDS, etc.) were examined and compared with 1997 results. Total dissolved gas levels were greatly reduced in 1998, compared with 1997, likely resulting from the relatively normal water year experienced in 1998. Mean water temperatures were similar to what was observed in past years, with a maximum of 22.7 C and a minimum of 2.6 C. Oxygen concentrations were also relatively normal, with a maximum of 16.6 mg/L, and a minimum of 0.9 mg/L. Phytoplankton in Lake Roosevelt was primarily composed of microplankton (29.6%), Cryptophyceae (21.7%), and Bacillriophyceae (17.0 %). Mean total phytoplankton chlorophyll a maximum concentration occurred in May (3.53 mg/m{sup 3}), and the minimum in January (0.39 mg/m{sup 3}). Phytoplankton chlorophyll a concentrations appear to be influenced by hydro-operations and temperature. Trophic status as indicated by phytoplankton chlorophyll a concentrations place Lake Roosevelt in the oligomesotrophic range. Periphyton colonization <span class="hlt">rates</span> and biovolume were significantly greater at a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000DSRI...47.2243W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000DSRI...47.2243W"><span>DMSP and DMS dynamics and microzooplankton <span class="hlt">grazing</span> in the Labrador Sea: application of the dilution technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wolfe, Gordon V.; Levasseur, Maurice; Cantin, Guy; Michaud, Sonia</p> <p>2000-12-01</p> <p>We adapted the dilution technique to study microzooplankton <span class="hlt">grazing</span> of algal dimethylsulfoniopropionate (DMSP) vs. Chl a, and to estimate the impact of microzooplankton <span class="hlt">grazing</span> on dimethyl sulfide (DMS) production in the Labrador Sea. Phytoplankton numbers were dominated by autotrophic nanoflagellates in the Labrador basin, but diatoms and colonial Phaeocystis pouchetii contributed significantly to phytomass at several high chlorophyll stations and on the Newfoundland and Greenland shelfs. Throughout the region, growth of algal Chl a and DMSP was generally high (0.2-1 d -1), but <span class="hlt">grazing</span> <span class="hlt">rates</span> were lower and more variable, characteristic of the early spring bloom period. Production and consumption of Chl a vs. DMSP followed no clear pattern, and sometimes diverged greatly, likely because of their differing distributions among algal prey taxa and size class. In several experiments where Phaeocystis was abundant, we observed DMS production proportional to <span class="hlt">grazing</span> <span class="hlt">rate</span>, and we found clear evidence of DMS production by this haptophyte following physical stress such as sparging or filtration. It is possible that <span class="hlt">grazing</span>-activated DMSP cleavage by Phaeocystis contributes to grazer deterrence: protozoa and copepods apparently avoided healthy colonies (as judged by relative growth and <span class="hlt">grazing</span> <span class="hlt">rates</span> of Chl a and DMSP), and <span class="hlt">grazing</span> of Phaeocystis was significant only at one station where cells were in poor condition. Although we hoped to examine selective <span class="hlt">grazing</span> on or against DMSP-containing algal prey, the dilution technique cannot differentiate selective ingestion and varying digestion <span class="hlt">rates</span> of Chl a and DMSP. We also found that the dilution method alone was poorly suited for assessing the impact of <span class="hlt">grazing</span> on dissolved sulfur pools, because of rapid microbial consumption and the artifactual release of DMSP and DMS during filtration. Measuring and understanding the many processes affecting organosulfur cycling by the microbial food web in natural populations remain a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol1/pdf/CFR-2010-title25-vol1-sec167-11.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol1/pdf/CFR-2010-title25-vol1-sec167-11.pdf"><span>25 CFR 167.11 - Tenure of <span class="hlt">grazing</span> permits.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... Tenure of <span class="hlt">grazing</span> permits. (a) All active regular <span class="hlt">grazing</span> permits shall be for one year and shall be... § 167.8 may become a livestock operator by obtaining an active <span class="hlt">grazing</span> permit through negotiability or... handle each matter of unused <span class="hlt">grazing</span> permit or portions of <span class="hlt">grazing</span> permits on individual merits. Where...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec4130-5.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec4130-5.pdf"><span>43 CFR 4130.5 - Free-use <span class="hlt">grazing</span> permits.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Free-use <span class="hlt">grazing</span> permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) <span class="hlt">GRAZING</span> ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing <span class="hlt">Grazing</span> Use § 4130.5 Free-use <span class="hlt">grazing</span> permits. (a) A free-use <span class="hlt">grazing</span> permit shall be issued to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec4130-5.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec4130-5.pdf"><span>43 CFR 4130.5 - Free-use <span class="hlt">grazing</span> permits.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Free-use <span class="hlt">grazing</span> permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) <span class="hlt">GRAZING</span> ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing <span class="hlt">Grazing</span> Use § 4130.5 Free-use <span class="hlt">grazing</span> permits. (a) A free-use <span class="hlt">grazing</span> permit shall be issued to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title43-vol2/pdf/CFR-2014-title43-vol2-sec4130-5.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title43-vol2/pdf/CFR-2014-title43-vol2-sec4130-5.pdf"><span>43 CFR 4130.5 - Free-use <span class="hlt">grazing</span> permits.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Free-use <span class="hlt">grazing</span> permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) <span class="hlt">GRAZING</span> ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing <span class="hlt">Grazing</span> Use § 4130.5 Free-use <span class="hlt">grazing</span> permits. (a) A free-use <span class="hlt">grazing</span> permit shall be issued to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec4130-5.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec4130-5.pdf"><span>43 CFR 4130.5 - Free-use <span class="hlt">grazing</span> permits.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Free-use <span class="hlt">grazing</span> permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) <span class="hlt">GRAZING</span> ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing <span class="hlt">Grazing</span> Use § 4130.5 Free-use <span class="hlt">grazing</span> permits. (a) A free-use <span class="hlt">grazing</span> permit shall be issued to...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...635039A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...635039A"><span>Chytrid parasitism facilitates trophic transfer between bloom-forming cyanobacteria and <span class="hlt">zooplankton</span> (Daphnia)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agha, Ramsy; Saebelfeld, Manja; Manthey, Christin; Rohrlack, Thomas; Wolinska, Justyna</p> <p>2016-10-01</p> <p>Parasites are rarely included in food web studies, although they can strongly alter trophic interactions. In aquatic ecosystems, poorly <span class="hlt">grazed</span> cyanobacteria often dominate phytoplankton communities, leading to the decoupling of primary and secondary production. Here, we addressed the interface between predator-prey and host-parasite interactions by conducting a life-table experiment, in which four Daphnia galeata genotypes were maintained on quantitatively comparable diets consisting of healthy cyanobacteria or cyanobacteria infected by a fungal (chytrid) parasite. In four out of five fitness parameters, at least one Daphnia genotype performed better on parasitised cyanobacteria than in the absence of infection. Further treatments consisting of purified chytrid zoospores and heterotrophic bacteria suspensions established the causes of improved fitness. First, Daphnia feed on chytrid zoospores which trophically upgrade cyanobacterial carbon. Second, an increase in heterotrophic bacterial biomass, promoted by cyanobacterial decay, provides an additional food source for Daphnia. In addition, chytrid infection induces fragmentation of cyanobacterial filaments, which could render cyanobacteria more edible. Our results demonstrate that chytrid parasitism can sustain <span class="hlt">zooplankton</span> under cyanobacterial bloom conditions, and exemplify the potential of parasites to alter interactions between trophic levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JSR....90...83L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JSR....90...83L"><span>Microzooplankton <span class="hlt">grazing</span> and selective feeding during bloom periods in the Tolo Harbour area as revealed by HPLC pigment analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Xiangjiang; Tang, Chi Hung; Wong, Chong Kim</p> <p>2014-07-01</p> <p>Dilution experiments were conducted to investigate microzooplankton <span class="hlt">grazing</span> impact on phytoplankton of different taxonomic groups and size fractions (< 5, 5-20, 20-200 μm) during spring and summer bloom periods at two different sites (inner Tolo Harbour and Tolo Channel) in the Tolo Harbour area, the northeastern coastal area of Hong Kong. Experiments combined with HPLC pigment analysis in three phytoplankton size fractions measured pigment and size specific phytoplankton growth <span class="hlt">rates</span> and microzooplankton <span class="hlt">grazing</span> <span class="hlt">rates</span>. Pigment-specific phytoplankton growth <span class="hlt">rates</span> ranged between 0.08 and 3.53 d- 1, while specific <span class="hlt">grazing</span> <span class="hlt">rates</span> of microzooplankton ranged between 0.07 and 2.82 d- 1. Highest specific <span class="hlt">rates</span> of phytoplankton growth and microzooplankton <span class="hlt">grazing</span> were both measured in fucoxanthin in 5-20 μm size fraction in inner Tolo Harbour in summer, which coincided with the occurrence of diatom bloom. Results showed significant correlations between phytoplankton growth and microzooplankton <span class="hlt">grazing</span> <span class="hlt">rates</span>. Microzooplankton placed high <span class="hlt">grazing</span> pressure on phytoplankton community. High microzooplankton <span class="hlt">grazing</span> impact on alloxanthin (2.63-5.13) suggested strong selection toward cryptophytes. Our results provided no evidence for size selective <span class="hlt">grazing</span> on phytoplankton by microzooplankton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title36-vol2/pdf/CFR-2010-title36-vol2-sec292-48.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title36-vol2/pdf/CFR-2010-title36-vol2-sec292-48.pdf"><span>36 CFR 292.48 - <span class="hlt">Grazing</span> activities.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... livestock <span class="hlt">grazing</span> is incompatible with the protection, restoration, or maintenance of fish and wildlife or their habitats; public outdoor recreation; conservation of scenic, wilderness, and scientific values...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24229787','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24229787"><span>Effect of pre-<span class="hlt">grazing</span> herbage mass on dairy cow performance, grass dry matter production and output from perennial ryegrass (Lolium perenne L.) pastures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wims, C M; Delaby, L; Boland, T M; O'Donovan, M</p> <p>2014-01-01</p> <p>A <span class="hlt">grazing</span> study was undertaken to examine the effect of maintaining three levels of pre-<span class="hlt">grazing</span> herbage mass (HM) on dairy cow performance, grass dry matter (DM) production and output from perennial ryegrass (Lolium perenne L.) pastures. Cows were randomly assigned to one of three pre-<span class="hlt">grazing</span> HM treatments: 1150 - Low HM (L), 1400 - Medium HM (M) or 2000 kg DM/ha - High HM (H). Herbage accumulation under <span class="hlt">grazing</span> was lowest (P<0.01) on the L treatment and cows <span class="hlt">grazing</span> the L pastures required more grass silage supplementation during the <span class="hlt">grazing</span> season (+73 kg DM/cow) to overcome pasture deficits due to lower pasture growth <span class="hlt">rates</span> (P<0.05). Treatment did not affect daily milk production or pasture intake, although cows <span class="hlt">grazing</span> the L pastures had to <span class="hlt">graze</span> a greater daily area (P<0.01) and increase <span class="hlt">grazing</span> time (P<0.05) to compensate for a lower pre-<span class="hlt">grazing</span> HM (P<0.01). The results indicate that, while pre-<span class="hlt">grazing</span> HM did not influence daily milk yield per cow, adapting the practise of <span class="hlt">grazing</span> low HM (1150 kg DM/ha) pasture reduces pasture DM production and at a system level may increase the requirement for imported feed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=340837&Lab=NHEERL&keyword=science+AND+information&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=340837&Lab=NHEERL&keyword=science+AND+information&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Using occupancy modeling to compare traditional versus DNA metabarcoding methods for characterizing <span class="hlt">zooplankton</span> biodiversity</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>DNA metabarcoding tools could increase our ability to detect changes in <span class="hlt">zooplankton</span> communities and to detect invasive <span class="hlt">zooplankton</span> taxa while they are still rare. Nonetheless, the use of DNA-metabarcoding for characterizing <span class="hlt">zooplankton</span> biodiversity in the Great Lakes has not bee...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AtmEn.174...66M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AtmEn.174...66M"><span>Annual methane budgets of sheep <span class="hlt">grazing</span> systems were regulated by <span class="hlt">grazing</span> intensities in the temperate continental steppe: A two-year case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Lei; Zhong, Mengying; Zhu, Yuhao; Yang, Helong; Johnson, Douglas A.; Rong, Yuping</p> <p>2018-02-01</p> <p>Methane (CH4) emission from animal husbandry accounts for a large percentage of anthropogenic contributions to CH4 emissions. Fully understanding of <span class="hlt">grazing</span> management effects on the CH4 budget is essential for mitigating CH4 emissions in the temperate <span class="hlt">grazing</span> steppe systems. Annual CH4 budgets for the sheep <span class="hlt">grazed</span> steppes at various <span class="hlt">grazing</span> intensities, un-<span class="hlt">grazing</span> (UG, 0 sheep ha-1year-1), defer <span class="hlt">grazing</span> (DG, 1.0 sheep ha-1 year-1), moderate <span class="hlt">grazing</span> (MG, 1.43 sheep ha-1year-1), and heavy <span class="hlt">grazing</span> (HG, 2.43 sheep ha-1year-1) were assessed across 2012-2014 in the agro-pastoral region of northern China. Annual soil CH4 uptake averaged across 2012-2014 were 1.1 ± 0.1, 2.4 ± 0.2, 2.2 ± 0.2, and 1.3 ± 0.1 kg CH4-C ha-1 for UG, DG (only 2013-2014), MG and HG sites. Non-growing season CH4 uptake comprised 50.0 ± 4.3% of annual CH4 uptake in 2012-2013 and 37.7 ± 2.0% in 2013-2014. DG and MG significantly promoted annual soil CH4 uptake (P < 0.05), while there was no difference between HG and UG (P > 0.05). Bell-shaped relationship was presented between stocking <span class="hlt">rates</span> and soil CH4 uptake (r2 = 0.59, P < 0.05). Annual soil CH4 uptake significant linearly and positively correlated with root biomass (r2 = 0.30, P < 0.05). Annual CH4 budgets for the <span class="hlt">grazed</span> grasslands were -1.1 ± 0.1, 5.7 ± 0.6, 11.5 ± 1.5 and 15.5 ± 1.3 kg CH4-C ha-1 year-1 in UG, DG (only 2013-2014), MG and HG across 2012-2014. Soil CH4 uptake could offset 29.7 ± 5.6, 15.9 ± 4.3 and 6.8 ± 1.0% of total annual CH4 emissions from sheep, sheepfold and faeces in DG, MG, and HG. All <span class="hlt">grazed</span> steppes are sources for atmospheric CH4 and the magnitude is regulated by <span class="hlt">grazing</span> intensities. Sheep CH4 emissions for 1-g liveweight gain were 0.21, 0.32 and 0.37 g CH4-C in DG, MG and HG, respectively. DG is the recommended <span class="hlt">grazing</span> management in this region to achieve greater herbage mass, higher sheep performance and lower CH4 emissions simultaneously.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/24926','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/24926"><span>Livestock <span class="hlt">grazing</span> and wildlife: developing compatabilities.</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Martin Vavra</p> <p>2005-01-01</p> <p>Livestock <span class="hlt">grazing</span> has been considered detrimental to wildlife habitat. Managed gazing programs, however, have the potential to maintain habitat diversity and quality. In cases in which single-species management predominates (sage-grouse [Centrocercus urophasianus] or elk [Cervus elaphus nelsoni] winter range), <span class="hlt">grazing</span> systems...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-05-26/pdf/2010-12707.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-05-26/pdf/2010-12707.pdf"><span>75 FR 29572 - Information Collection; <span class="hlt">Grazing</span> Management</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-05-26</p> <p>... Control Number 1004-0019] Information Collection; <span class="hlt">Grazing</span> Management AGENCY: Bureau of Land Management... submitted an information collection request to the Office of Management and Budget (OMB) for a 3-year... INFORMATION: Title: <span class="hlt">Grazing</span> Management (43 CFR 4120). OMB Number: 1004-0019. Forms: 4120-6 (Cooperative Range...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26553566','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26553566"><span>Reduced <span class="hlt">grazing</span> pressure delivers production and environmental benefits for the typical steppe of north China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Yingjun; Huang, Ding; Badgery, Warwick B; Kemp, David R; Chen, Wenqing; Wang, Xiaoya; Liu, Nan</p> <p>2015-11-10</p> <p>Degradation by overgrazing is common in many areas of the world and optimising grassland functions depends upon finding suitable <span class="hlt">grazing</span> tactics. This four-year study on the northern China steppe investigated combinations of rest, moderate or heavy <span class="hlt">grazing</span> pressure early in the summer growing season, then moderate or heavy <span class="hlt">grazing</span> in the mid and late season. Results showed that moderate <span class="hlt">grazing</span> pressure (~550 sheep equivalent (SE) <span class="hlt">grazing</span> days ha(-1) year(-1)) gave the optimal balance between maintaining a productive and diverse grassland, a profitable livestock system, and greenhouse gas mitigation. Further analyses identified that more conservative stocking (~400 SE <span class="hlt">grazing</span> days ha(-1) year(-1)) maintained a desirable Leymus chinensis composition and achieved a higher live weight gain of sheep. Early summer rest best maintained a desirable grassland composition, but had few other benefits and reduced incomes. These findings demonstrate that reducing <span class="hlt">grazing</span> pressure to half the current district stocking <span class="hlt">rates</span> can deliver improved ecosystem services (lower greenhouse gases and improved grassland composition) while sustaining herder incomes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1015272','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1015272"><span>Avian responses to late-season <span class="hlt">grazing</span> in a shrub-willow floodplain</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stanley, T.R.; Knopf, F.L.</p> <p>2002-01-01</p> <p>Riparian vegetation in western North America provides important habitat for breeding birds and valuable forage for <span class="hlt">grazing</span> livestock. Whereas a number of studies have documented the response of riparian vegetation to the removal of cattle, few have experimentally evaluated specific <span class="hlt">grazing</span> systems. We evaluated the responses of vegetation and breeding birds to two cycles of late-season (August–September) <span class="hlt">grazing</span> followed by 34 months of rest on the Arapaho National Wildlife Refuge, Colorado. We used a before-and-after control-impact (BACI) design, with two control (ungrazed) and two treatment ( <span class="hlt">grazed</span>) pastures composing the experimental units. Vegetation characteristics and bird densities were quantified on sample plots prior to and following two cycles of the treatment. We found no statistical differences in vegetation change and few differences in bird-density change among pastures. Inspection of means for pastures, however, suggests that changes in shrub vigor and spatial pattern differed among ungrazed and <span class="hlt">grazed</span> pastures and that changes in population density for three of the nine bird species and three guilds studied differed among pastures. Our results suggest that habitat for <span class="hlt">grazing</span>-sensitive birds may be restored while still allowing late-season <span class="hlt">grazing</span>, although the <span class="hlt">rate</span> at which species are recovered will be slower than if all cattle are removed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4639777','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4639777"><span>Reduced <span class="hlt">grazing</span> pressure delivers production and environmental benefits for the typical steppe of north China</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Yingjun; Huang, Ding; Badgery, Warwick B.; Kemp, David R.; Chen, Wenqing; Wang, Xiaoya; Liu, Nan</p> <p>2015-01-01</p> <p>Degradation by overgrazing is common in many areas of the world and optimising grassland functions depends upon finding suitable <span class="hlt">grazing</span> tactics. This four-year study on the northern China steppe investigated combinations of rest, moderate or heavy <span class="hlt">grazing</span> pressure early in the summer growing season, then moderate or heavy <span class="hlt">grazing</span> in the mid and late season. Results showed that moderate <span class="hlt">grazing</span> pressure (~550 sheep equivalent (SE) <span class="hlt">grazing</span> days ha−1 year−1) gave the optimal balance between maintaining a productive and diverse grassland, a profitable livestock system, and greenhouse gas mitigation. Further analyses identified that more conservative stocking (~400 SE <span class="hlt">grazing</span> days ha−1 year−1) maintained a desirable Leymus chinensis composition and achieved a higher live weight gain of sheep. Early summer rest best maintained a desirable grassland composition, but had few other benefits and reduced incomes. These findings demonstrate that reducing <span class="hlt">grazing</span> pressure to half the current district stocking <span class="hlt">rates</span> can deliver improved ecosystem services (lower greenhouse gases and improved grassland composition) while sustaining herder incomes. PMID:26553566</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014BGD....1113157Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014BGD....1113157Z"><span>Testing functional trait-based mechanisms underpinning plant responses to <span class="hlt">grazing</span> and linkages to ecosystem functioning in grasslands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, S. X.; Li, W. H.; Lan, Z. C.; Ren, H. Y.; Wang, K. B.; Bai, Y. F.</p> <p>2014-09-01</p> <p>Abundant evidence has shown that <span class="hlt">grazing</span> alters plant functional traits, ecological strategies, community structure, and ecosystem functioning of grasslands. Few studies, however, have examined how plant responses to <span class="hlt">grazing</span> are mediated by resource availability and functional group identity. We test functional trait-based mechanisms underlying the responses of different life forms to <span class="hlt">grazing</span> and linkages to ecosystem functioning along a soil moisture gradient in the Inner Mongolia grassland. A principal component analysis (PCA) based on 9 traits × 276 species matrix showed that the plant size spectrum (i.e., individual biomass), leaf economics spectrum (leaf N content and leaf density), and light competition spectrum (height and stem-leaf biomass ratio) distinguished plant species responses to <span class="hlt">grazing</span>. The three life forms exhibited differential strategies as indicated by trait responses to <span class="hlt">grazing</span>. The annuals and biennials adopted <span class="hlt">grazing</span>-tolerant strategies associated with high growth <span class="hlt">rate</span>, reflected by high leaf N content and specific leaf area. The perennial grasses exhibited <span class="hlt">grazing</span>-tolerant strategies associated with great regrowth capacity and high palatability scores, whereas perennial forbs showed <span class="hlt">grazing</span>-avoidant strategies with short stature and low palatability scores. In addition, the dominant perennial bunchgrasses exhibited mixed tolerance-resistance strategies to <span class="hlt">grazing</span> and mixed acquisitive-conservative strategies in resource utilization. <span class="hlt">Grazing</span> increased the relative abundance of perennial forbs with low palatability in the wet and fertile meadow, but it promoted perennial grasses with high palatability in the dry and infertile typical steppe. Our findings suggest that the effects of <span class="hlt">grazing</span> on plant functional traits are dependent on both the abiotic (e.g., soil moisture) and biotic (e.g., plant functional group identity and composition) factors. <span class="hlt">Grazing</span>-induced shifts in functional group composition are largely dependent on resource</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=331157','PESTICIDES'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=331157"><span>Development of a Multimetric Indicator of Pelagic <span class="hlt">Zooplankton</span> ...</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>We used <span class="hlt">zooplankton</span> data collected for the 2012 National Lakes Assessment (NLA) to develop multimetric indices (MMIs) for five aggregated ecoregions of the conterminous USA (Coastal Plains, Eastern Highlands, Plains, Upper Midwest, and Western Mountains and Xeric [“West’]). We classified candidate metrics into six categories: We evaluated the performance of candidate metrics, and used metrics that had passed these screens to calculate all possible candidate MMIs that included at least one metric from each category. We selected the candidate MMI that had high responsiveness, a reasonable value for repeatability, low mean pairwise correlation among component metrics, and, when possible, a maximum pairwise correlation among component metrics that was <0.7. We were able to develop MMIs that were sufficiently responsive and repeatable to assess ecological condition for the NLA without the need to reduce the effects of natural variation using models. We did not observe effects of either lake size, lake origin, or site depth on the MMIs. The MMIs appear to respond more strongly to increased nutrient concentrations than to shoreline habitat conditions. Improving our understanding of how <span class="hlt">zooplankton</span> assemblages respond to increased human disturbance, and obtaining more complete autecological information for <span class="hlt">zooplankton</span> taxa would likely improve MMIs developed for future assessments. Using <span class="hlt">zooplankton</span> assemblage data from the 2012 National Lakes Assessment (NLA),</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034891','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034891"><span>Lake St. Clair <span class="hlt">zooplankton</span>: Evidence for post-Dreissena changes</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>David, Katherine A.; Davis, Bruce M.; Hunter, R. Douglas</p> <p>2009-01-01</p> <p>We surveyed the <span class="hlt">zooplankton</span> of Lake St. Clair at 12 sites over ten dates from May to October 2000. Mean <span class="hlt">zooplankton</span> density by site and date was 168.6 individuals/L, with Dreissena spp. veligers the most abundant taxon at 122.7 individuals/L. Rotifers, copepods, and cladocerans were far lower in mean abundance than in the early 1970s (rotifers, 20.9/L; copepods, 18.1/L; and cladocerans, 6.8/L). Species richness of <span class="hlt">zooplankton</span> taxa in 2000 was 147, which was virtually unchanged from that of the first reported survey in 1894. Overall, the decline in abundance was greatest for rotifers (-90%) and about equal for cladocerans (-69%) and copepods (-66%). The decrease in abundance of Daphnia spp. was especially dramatic in Canadian waters. The decline in the southeastern region was significant for all three major groups of <span class="hlt">zooplankton</span>, whereas in the northwestern region the decline was significant only for rotifers. From June to August 2000, Lake St. Clair open waters were numerically dominated by Dreissena spp. veligers, with a reduced abundance of rotifers and crustaceans compared to pre-Dreissena spp. surveys. Mean nutrient concentrations were not different from the 1970s, but Secchi depth (greater) and chlorophyll a concentration (lower) were. Disproportionate reduction in rotifer abundance is consistent with hypotheses implicating direct consumption by settled Dreissena spp. Reduction of crustaceans is likely due to more complex interactions including removal of nauplii as well as resource competition for phytoplankton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=60169&keyword=copepod&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=60169&keyword=copepod&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>FORAGE FISH AND <span class="hlt">ZOOPLANKTON</span> COMMUNITY COMPOSITION IN WESTERN LAKE SUPERIOR</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>We assessed the abundance, size, and species composition of the fish and <span class="hlt">zooplankton</span> communities of western Lake Superior during 1996 and 1997. Data were analyzed for 3 ecoregions (Duluth-Superior (1), Apostle Islands (2), Minnesota coast (3) differing in lake bathymetry, phsiodo...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70032832','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70032832"><span>Distribution and abundance of <span class="hlt">zooplankton</span> populations in Crater Lake, Oregon</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Larson, G.L.; McIntire, C.D.; Buktenica, M.W.; Girdner, S.F.; Truitt, R.E.</p> <p>2007-01-01</p> <p>The <span class="hlt">zooplankton</span> assemblages in Crater Lake exhibited consistency in species richness and general taxonomic composition, but varied in density and biomass during the period between 1988 and 2000. Collectively, the assemblages included 2 cladoceran taxa and 10 rotifer taxa (excluding rare taxa). Vertical habitat partitioning of the water column to a depth of 200 m was observed for most species with similar food habits and/or feeding mechanisms. No congeneric replacement was observed. The dominant species in the assemblages were variable, switching primarily between periods of dominance of Polyarthra-Keratella cochlearis and Daphnia. The unexpected occurrence and dominance of Asplanchna in 1991 and 1992 resulted in a major change in this typical temporal shift between Polyarthra-K. cochlearis and Daphnia. Following a collapse of the <span class="hlt">zooplankton</span> biomass in 1993 that was probably caused by predation from Asplanchna, Kellicottia dominated the <span class="hlt">zooplankton</span> assemblage biomass between 1994 and 1997. The decline in biomass of Kellicottia by 1998 coincided with a dramatic increase in Daphnia biomass. When Daphnia biomass declined by 2000, Keratella biomass increased again. Thus, by 1998 the assemblage returned to the typical shift between Keratella-Polyarthra and Daphnia. Although these observations provided considerable insight about the interannual variability of the <span class="hlt">zooplankton</span> assemblages in Crater Lake, little was discovered about mechanisms behind the variability. When abundant, kokanee salmon may have played an important role in the disappearance of Daphnia in 1990 and 2000 either through predation, inducing diapause, or both. ?? 2007 Springer Science+Business Media B.V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PrOce.141..179W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PrOce.141..179W"><span>The ICES Working Group on <span class="hlt">Zooplankton</span> Ecology: Accomplishments of the first 25 years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wiebe, Peter H.; Harris, Roger; Gislason, Astthor; Margonski, Piotr; Skjoldal, Hein Rune; Benfield, Mark; Hay, Steve; O'Brien, Todd; Valdés, Luis</p> <p>2016-02-01</p> <p>The ICES Study Group on <span class="hlt">Zooplankton</span> Ecology was created in 1991 to address issues of current and future concern within the field of <span class="hlt">zooplankton</span> ecology. Within three years it became the ICES Working Group on <span class="hlt">Zooplankton</span> Ecology (ICES WGZE) and this unique group in the world's oceanographic community has now been active for 25 years. This article reviews and synthesizes the products, and major accomplishments of the group. Achievements of the group, including the <span class="hlt">Zooplankton</span> Methodology Manual, the <span class="hlt">Zooplankton</span> Status Reports, and the International <span class="hlt">Zooplankton</span> Symposia, have had an important impact on the wider field. Among the future issues that remain to be addressed by the group are the assessment of exploratory fisheries on <span class="hlt">zooplankton</span> and micronekton species; further development of the <span class="hlt">zooplankton</span> time-series; compilation and integration of allometric relationships for <span class="hlt">zooplankton</span> species, and evaluation of new methodologies for the study of <span class="hlt">zooplankton</span> distribution, abundance, physiology, and genetics. Marine science is an increasingly global undertaking and groups such as the ICES WGZE will continue to be essential to the advancement of understanding of <span class="hlt">zooplankton</span> community structure and population dynamics in the world's oceans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GBioC..31.1656G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GBioC..31.1656G"><span>Pilot Study on Potential Impacts of Fisheries-Induced Changes in <span class="hlt">Zooplankton</span> Mortality on Marine Biogeochemistry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Getzlaff, Julia; Oschlies, Andreas</p> <p>2017-11-01</p> <p>In this pilot study we link the yield of industrial fisheries to changes in the <span class="hlt">zooplankton</span> mortality in an idealized way accounting for different target species (planktivorous fish—decreased <span class="hlt">zooplankton</span> mortality; large predators—increased <span class="hlt">zooplankton</span> mortality). This indirect approach is used in a global coupled biogeochemistry circulation model to estimate the range of the potential impact of industrial fisheries on marine biogeochemistry. The simulated globally integrated response on phytoplankton and primary production is in line with expectations—a high (low) <span class="hlt">zooplankton</span> mortality results in a decrease (increase) of <span class="hlt">zooplankton</span> and an increase (decrease) of phytoplankton. In contrast, the local response of <span class="hlt">zooplankton</span> and phytoplankton depends on the region under consideration: In nutrient-limited regions, an increase (decrease) in <span class="hlt">zooplankton</span> mortality leads to a decrease (increase) in both <span class="hlt">zooplankton</span> and phytoplankton biomass. In contrast, in nutrient-replete regions, such as upwelling regions, we find an opposing response: an increase (decrease) of the <span class="hlt">zooplankton</span> mortality leads to an increase (decrease) in both <span class="hlt">zooplankton</span> and phytoplankton biomass. The results are further evaluated by relating the potential fisheries-induced changes in <span class="hlt">zooplankton</span> mortality to those driven by CO2 emissions in a business-as-usual 21st century emission scenario. In our idealized case, the potential fisheries-induced impact can be of similar size as warming-induced changes in marine biogeochemistry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSMOS22B..04L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSMOS22B..04L"><span>Effects of Climate on the <span class="hlt">Zooplankton</span> of the California Current</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lavaniegos, B. E.</p> <p>2007-05-01</p> <p>Almost six decades of sampling of the California Current system, carried out by the CalCOFI program (California Cooperative Fisheries Investigation) complemented by a decade of observations from the IMECOCAL program (Investigaciones Mexicanas de la Corriente de California), have revealed changing patterns in <span class="hlt">zooplankton</span> abundances, species composition, and distributions over interannual through multidecadal time scales. Interannual changes associated with ENSO variability are manifested as strong but transitory perturbations in the mean annual cycle in seasonal abundances (and distributions) of particular species. An investigation of longer- term change, limited to the region off southern California, shows a persistent decline in <span class="hlt">zooplankton</span> volumes (a proxy for overall biomass of macrozooplankton) between 1977 and 1998 that is considered to be a response to the well documented shift in basin-scale climate forcing that occurred in 1976-77. Further examination of this decline in <span class="hlt">zooplankton</span> volumes indicates that it was due principally to the disappearance of several salp species after 1977. Other species and functional groups did not decline after the change in climate regime, while some species have followed persistent secular trends that appear to be associated more with the phenomenon of long-term global warming. Differences in the regional responses to climate change throughout the California Current system have also been observed recently in the spatial distribution of <span class="hlt">zooplankton</span> biomass and changes in latitudinal ranges of certain species. For example, <span class="hlt">zooplankton</span> biomass in the Baja California region show typical values for the 1997-98 El Niño that were followed by a decrease during the sharp transition to the cool La Niña conditions in 1999. This contrasts with the nearby region off southern California that was characterized by reduced biomass during the El Niño period and the subsequent recovery during the La Niña. Another regional contrast in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28177410','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28177410"><span>Combining Restricted <span class="hlt">Grazing</span> and Nitrification Inhibitors to Reduce Nitrogen Leaching on New Zealand Dairy Farms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Romera, Alvaro J; Cichota, Rogerio; Beukes, Pierre C; Gregorini, Pablo; Snow, Val O; Vogeler, Iris</p> <p>2017-01-01</p> <p>Intensification of pastoral dairy systems often means more nitrogen (N) leaching. A number of mitigation strategies have been proposed to reduce or reverse this trend. The main strategies focus on reducing the urinary N load onto pastures or reducing the <span class="hlt">rate</span> of nitrification once the urine has been deposited. Restricted <span class="hlt">grazing</span> is an example of the former and the use of nitrification inhibitors an example of the latter. A relevant concern is the cost effectiveness of these strategies, independently and jointly. To address this concern, we employed a modeling approach to estimate N leaching with and without the use of these mitigation options from a typical <span class="hlt">grazing</span> dairy farm in New Zealand. Three restricted <span class="hlt">grazing</span> options were modeled with and without a nitrification inhibitor (dicyandiamide, DCD) and the results were compared with a baseline farm (no restricted <span class="hlt">grazing</span>, no inhibitor). Applying DCD twice a year, closely following the cows after an autumn and winter <span class="hlt">grazing</span> round, has the potential to reduce annualized and farm-scale N leaching by ∼12%, whereas restricted <span class="hlt">grazing</span> had leaching reductions ranging from 23 to 32%, depending on the timing of restricted <span class="hlt">grazing</span>. Combining the two strategies resulted in leaching reductions of 31 to 40%. The abatement cost per kilogram of N leaching reduction was NZ$50 with DCD, NZ$32 to 37 for restricted <span class="hlt">grazing</span>, and NZ$40 to 46 when the two were combined. For the range analyzed, all treatments indicated similar cost per percentage unit of mitigated N leaching, demonstrating that restricted <span class="hlt">grazing</span> and nitrification inhibitors can be effective when used concurrently. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26454684','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26454684"><span>Reproductive performance of ewes <span class="hlt">grazing</span> lucerne during different periods around mating.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Robertson, S M; Clayton, E H; Friend, M A</p> <p>2015-11-01</p> <p>High intake of lucerne pastures or feeding of other high quality diets during early pregnancy may increase embryo mortality, negating any benefit of improved nutrition on ovulation <span class="hlt">rate</span> in ewes. This study was conducted to determine whether <span class="hlt">grazing</span> ewes on lucerne (Medicago sativa) pastures for 7 days prior to and throughout joining would result in greater foetal numbers than if ewes were removed 7 days after the commencement of joining, or if ewes <span class="hlt">grazed</span> senescent pasture throughout the joining period. Merino ewes (300) were allocated to two replicates of three treatments, <span class="hlt">grazing</span> pastures between Days -7 and 36 of an unsynchronised, natural autumn joining. <span class="hlt">Grazing</span> lucerne to Day 7 of joining resulted in 30% more (P<0.05) foetuses per ewe than <span class="hlt">grazing</span> senescent pasture (1.60±0.07 and 1.31±0.07, respectively), and 19% more lambs marked per ewe joined. Extending <span class="hlt">grazing</span> of lucerne past Day 7 of joining did not result in additional foetuses per ewe (1.61±0.06) in comparison with only <span class="hlt">grazing</span> lucerne to Day 7 of joining. Greater than 80% of ewes mated during the first 14 days of joining, and the proportions of ewes returning to oestrus and re-mating (0.18±0.022) and of non-pregnant (0.09±0.017) ewes were similar (P>0.05) among all treatment groups, suggesting no differences between treatments in embryo mortality. <span class="hlt">Grazing</span> naturally cycling ewes on lucerne prior to and during joinings in autumn is recommended as a means to increase the number of lambs born, although additional gains may not be obtained by <span class="hlt">grazing</span> past day seven of joining. Copyright © 2015 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27220222','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27220222"><span>A meta-analysis of <span class="hlt">zooplankton</span> functional traits influencing ecosystem function.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hébert, Marie-Pier; Beisner, Beatrix E; Maranger, Roxane</p> <p>2016-04-01</p> <p>The use of functional traits to characterize community composition has been proposed as a more effective way to link community structure to ecosystem functioning. Organismal morphology, body stoichiometry, and physiology can be readily linked to large-scale ecosystem processes through functional traits that inform on interspecific and species-environment interactions; yet such effect traits are still poorly included in trait-based approaches. Given their key trophic position in aquatic ecosystems, individual <span class="hlt">zooplankton</span> affect energy fluxes and elemental processing. We compiled a large database of <span class="hlt">zooplankton</span> traits contributing to carbon, nitrogen, and phosphorus cycling and examined the effect of classification and habitat (marine vs. freshwater) on trait relationships. Respiration and nutrient excretion <span class="hlt">rates</span> followed mass-dependent scaling in both habitats, with exponents ranging from 0.70 to 0.90. Our analyses revealed surprising differences in allometry and respiration between habitats, with freshwater species having lower length-specific mass and three times higher mass-specific respiration <span class="hlt">rates</span>. These differences in traits point to implications for ecological strategies as well as overall carbon storage and fluxes based on habitat type. Our synthesis quantifies multiple trait relationships and links organisms to ecosystem processes they influence, enabling a more complete integration of aquatic community ecology and biogeochemistry through the promising use of effect traits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28851143','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28851143"><span>Exposure and effects of sediment-spiked fludioxonil on macroinvertebrates and <span class="hlt">zooplankton</span> in outdoor aquatic microcosms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yin, Xiao H; Brock, Theo C M; Barone, Lidia E; Belgers, J Dick M; Boerwinkel, Marie-Claire; Buijse, Laura; van Wijngaarden, René P A; Hamer, Mick; Roessink, Ivo</p> <p>2018-01-01</p> <p>Information from effects of pesticides in sediments at an ecosystem level, to validate current and proposed risk assessment procedures, is scarce. A sediment-spiked outdoor freshwater microcosm experiment was conducted with fludioxonil (lipophilic, non-systemic fungicide) to study exposure dynamics and treatment-related responses of benthic and pelagic macroinvertebrates and <span class="hlt">zooplankton</span>. Besides blank control and solvent control systems the experiment had six different treatment levels (1.7-614mga.s./kg dry sediment) based around the reported 28-d No Observed Effect Concentration (NOEC) for Chironomus riparius (40mga.s./kg dry sediment). Twelve systems were available per treatment of which four were sacrificed on each of days 28, 56 and 84 after microcosm construction. Fludioxonil persisted in the sediment and mean measured concentrations were 53-82% of the initial concentration after 84days. The dissipation <span class="hlt">rate</span> increased with the treatment level. Also exposure concentrations in overlying water were long-term, with highest concentrations 28days after initiation of the experiment. Sediment-dwelling Oligochaeta and pelagic Rotifera and Cladocera showed the most pronounced treatment-related declines. The most sensitive sediment-dwelling oligochaete was Dero digitata (population NOEC 14.2mga.s./kg dry sediment). The same NOEC was calculated for the sediment-dwelling macroinvertebrate community. The most sensitive <span class="hlt">zooplankton</span> species was the cladoceran Diaphanosoma brachyurum (NOEC of 1.6μga.s./L in overlying water corresponding to 5.0mga.s./kg dry sediment). At the two highest treatments several rotifer taxa showed a pronounced decrease, while the <span class="hlt">zooplankton</span> community-level NOEC was 5.6μga.s./L (corresponding to 14.2mga.s./kg dry sediment). <span class="hlt">Zooplankton</span> taxa calanoid Copepoda and Daphnia gr. longispina showed a pronounced treatment-related increase (indirect effects). Consequently, an assessment factor of 10 to the chronic laboratory NOECs of Chironomus riparius</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24124552','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24124552"><span>The impact of fish predation and cyanobacteria on <span class="hlt">zooplankton</span> size structure in 96 subtropical lakes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Jing; Xie, Ping; Tao, Min; Guo, Longgen; Chen, Jun; Li, Li; Xuezhen Zhang; Zhang, Lu</p> <p>2013-01-01</p> <p><span class="hlt">Zooplankton</span> are relatively small in size in the subtropical regions. This characteristic has been attributed to intense predation pressure, high nutrient loading and cyanobacterial biomass. To provide further information on the effect of predation and cyanobacteria on <span class="hlt">zooplankton</span> size structure, we analyzed data from 96 shallow aquaculture lakes along the Yangtze River. Contrary to former studies, both principal components analysis and multiple regression analysis showed that the mean <span class="hlt">zooplankton</span> size was positively related to fish yield. The studied lakes were grouped into three types, namely, natural fishing lakes with low nutrient loading (Type1), planktivorous fish-dominated lakes (Type 2), and eutrophic lakes with high cyanobacterial biomass (Type 3). A marked difference in <span class="hlt">zooplankton</span> size structure was found among these groups. The greatest mean <span class="hlt">zooplankton</span> size was observed in Type 2 lakes, but <span class="hlt">zooplankton</span> density was the lowest. <span class="hlt">Zooplankton</span> abundance was highest in Type 3 lakes and increased with increasing cyanobacterial biomass. <span class="hlt">Zooplankton</span> mean size was negatively correlated with cyanobacterial biomass. No obvious trends were found in Type 1 lakes. These results were reflected by the normalized biomass size spectrum, which showed a unimodal shape with a peak at medium sizes in Type 2 lakes and a peak at small sizes in Type 3 lakes. These results indicated a relative increase in medium-sized and small-sized species in Types 2 and 3 lakes, respectively. Our results suggested that fish predation might have a negative effect on <span class="hlt">zooplankton</span> abundance but a positive effect on <span class="hlt">zooplankton</span> size structure. High cyanobacterial biomass most likely caused a decline in the <span class="hlt">zooplankton</span> size and encouraged the proliferation of small <span class="hlt">zooplankton</span>. We suggest that both planktivorous fish and cyanobacteria have substantial effects on the shaping of <span class="hlt">zooplankton</span> community, particularly in the lakes in the eastern plain along the Yangtze River where aquaculture is widespread</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3790690','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3790690"><span>The Impact of Fish Predation and Cyanobacteria on <span class="hlt">Zooplankton</span> Size Structure in 96 Subtropical Lakes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Jing; Xie, Ping; Tao, Min; Guo, Longgen; Chen, Jun; Li, Li; XueZhen Zhang; Zhang, Lu</p> <p>2013-01-01</p> <p><span class="hlt">Zooplankton</span> are relatively small in size in the subtropical regions. This characteristic has been attributed to intense predation pressure, high nutrient loading and cyanobacterial biomass. To provide further information on the effect of predation and cyanobacteria on <span class="hlt">zooplankton</span> size structure, we analyzed data from 96 shallow aquaculture lakes along the Yangtze River. Contrary to former studies, both principal components analysis and multiple regression analysis showed that the mean <span class="hlt">zooplankton</span> size was positively related to fish yield. The studied lakes were grouped into three types, namely, natural fishing lakes with low nutrient loading (Type1), planktivorous fish-dominated lakes (Type 2), and eutrophic lakes with high cyanobacterial biomass (Type 3). A marked difference in <span class="hlt">zooplankton</span> size structure was found among these groups. The greatest mean <span class="hlt">zooplankton</span> size was observed in Type 2 lakes, but <span class="hlt">zooplankton</span> density was the lowest. <span class="hlt">Zooplankton</span> abundance was highest in Type 3 lakes and increased with increasing cyanobacterial biomass. <span class="hlt">Zooplankton</span> mean size was negatively correlated with cyanobacterial biomass. No obvious trends were found in Type 1 lakes. These results were reflected by the normalized biomass size spectrum, which showed a unimodal shape with a peak at medium sizes in Type 2 lakes and a peak at small sizes in Type 3 lakes. These results indicated a relative increase in medium-sized and small-sized species in Types 2 and 3 lakes, respectively. Our results suggested that fish predation might have a negative effect on <span class="hlt">zooplankton</span> abundance but a positive effect on <span class="hlt">zooplankton</span> size structure. High cyanobacterial biomass most likely caused a decline in the <span class="hlt">zooplankton</span> size and encouraged the proliferation of small <span class="hlt">zooplankton</span>. We suggest that both planktivorous fish and cyanobacteria have substantial effects on the shaping of <span class="hlt">zooplankton</span> community, particularly in the lakes in the eastern plain along the Yangtze River where aquaculture is widespread</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title36-vol2/pdf/CFR-2010-title36-vol2-sec293-7.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title36-vol2/pdf/CFR-2010-title36-vol2-sec293-7.pdf"><span>36 CFR 293.7 - <span class="hlt">Grazing</span> of livestock.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false <span class="hlt">Grazing</span> of livestock. 293.7...-PRIMITIVE AREAS § 293.7 <span class="hlt">Grazing</span> of livestock. (a) The <span class="hlt">grazing</span> of livestock, where such use was established..., shall be permitted to continue under the general regulations covering <span class="hlt">grazing</span> of livestock on the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title36-vol2/pdf/CFR-2010-title36-vol2-sec222-4.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title36-vol2/pdf/CFR-2010-title36-vol2-sec222-4.pdf"><span>36 CFR 222.4 - Changes in <span class="hlt">grazing</span> permits.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... RANGE MANAGEMENT <span class="hlt">Grazing</span> and Livestock Use on the National Forest System § 222.4 Changes in <span class="hlt">grazing</span>... use permits in whole or in part as follows: (1) Cancel permits where lands <span class="hlt">grazed</span> under the permit are... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Changes in <span class="hlt">grazing</span> permits...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec4110-3.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec4110-3.pdf"><span>43 CFR 4110.3 - Changes in <span class="hlt">grazing</span> preference.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Changes in <span class="hlt">grazing</span> preference. 4110.3... Qualifications and Preference § 4110.3 Changes in <span class="hlt">grazing</span> preference. (a) The authorized officer will periodically review the <span class="hlt">grazing</span> preference specified in a <span class="hlt">grazing</span> permit or lease and make changes in the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29696884','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29696884"><span>[Relation between species distribution of plant community and soil factors under <span class="hlt">grazing</span> in alpine meadow].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min</p> <p>2017-12-01</p> <p>The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different <span class="hlt">grazing</span> intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the <span class="hlt">grazing</span> caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low <span class="hlt">grazing</span> intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of <span class="hlt">grazing</span> intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against <span class="hlt">grazing</span> intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration <span class="hlt">rate</span> and large aggregate index were significantly changed with <span class="hlt">grazing</span> intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under <span class="hlt">grazing</span>. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest <span class="hlt">rate</span> of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on <span class="hlt">grazed</span> alpine meadow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1015655','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1015655"><span>Effects of hydrology on <span class="hlt">zooplankton</span> communities in high-mountain ponds, Mount Rainier National Park, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Girdner, Scott; Larson, Gary L.</p> <p>1995-01-01</p> <p>Ten high-mountain ponds in Mount Rainier National Park, Washington State, were studied from ice-out in June through September1992 to investigate the influences of fluctuating pond volumes on <span class="hlt">zooplankton</span> communities. All of the ponds were at maximum volume immediately after ice-out. The temporary pond with the shortest wet phase was inhabited by rotifer taxa with short generation times and a crustacean taxon with the ability to encyst as drought-resistant resting bodies at immature stages of development. Dominant <span class="hlt">zooplankton</span> taxa in three other temporary ponds and six permanent ponds were similar. Rotifer densities typically were lower in temporary ponds relative to those in permanent ponds, although Brachionus urceolaris was abundant shortly before the temporary ponds dried. Large volume loss was associated with large declines in total abundances of crustacean populations. Daphnia rosea was not present in temporary ponds following fall recharge. In deep-permanent ponds, copepods had slower developmental <span class="hlt">rates</span>, smaller temporal changes in total abundances of crustacean populations and two additional large-bodied crustacean taxa were present relative to the characteristics of crustacean communities in shallow-permanent ponds. Owing to their small sizes and sensitivity to environmental change, collectively ponds such as these may provide an early signal of long-term climate change in aquatic systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title25-vol1/pdf/CFR-2011-title25-vol1-sec167-8.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title25-vol1/pdf/CFR-2011-title25-vol1-sec167-8.pdf"><span>25 CFR 167.8 - <span class="hlt">Grazing</span> rights.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-04-01</p> <p>... ownership records as established in accordance with § 167.7 or who have acquired <span class="hlt">grazing</span> rights by marriage..., separation, threatened family disruption, and permits of deceased permittees shall be the responsibility of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title25-vol1/pdf/CFR-2014-title25-vol1-sec167-8.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title25-vol1/pdf/CFR-2014-title25-vol1-sec167-8.pdf"><span>25 CFR 167.8 - <span class="hlt">Grazing</span> rights.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-04-01</p> <p>... ownership records as established in accordance with § 167.7 or who have acquired <span class="hlt">grazing</span> rights by marriage..., separation, threatened family disruption, and permits of deceased permittees shall be the responsibility of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title25-vol1/pdf/CFR-2013-title25-vol1-sec167-8.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title25-vol1/pdf/CFR-2013-title25-vol1-sec167-8.pdf"><span>25 CFR 167.8 - <span class="hlt">Grazing</span> rights.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-04-01</p> <p>... ownership records as established in accordance with § 167.7 or who have acquired <span class="hlt">grazing</span> rights by marriage..., separation, threatened family disruption, and permits of deceased permittees shall be the responsibility of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title25-vol1/pdf/CFR-2012-title25-vol1-sec167-8.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title25-vol1/pdf/CFR-2012-title25-vol1-sec167-8.pdf"><span>25 CFR 167.8 - <span class="hlt">Grazing</span> rights.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-04-01</p> <p>... ownership records as established in accordance with § 167.7 or who have acquired <span class="hlt">grazing</span> rights by marriage..., separation, threatened family disruption, and permits of deceased permittees shall be the responsibility of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title36-vol2/pdf/CFR-2011-title36-vol2-sec292-48.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title36-vol2/pdf/CFR-2011-title36-vol2-sec292-48.pdf"><span>36 CFR 292.48 - <span class="hlt">Grazing</span> activities.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... RECREATION AREAS Hells Canyon National Recreation Area-Federal Lands § 292.48 <span class="hlt">Grazing</span> activities. The... and located to minimize their impact on scenic, cultural, fish and wildlife, and other resources in... conditions which protect and conserve riparian areas. ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=346205','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=346205"><span>Does pulse-<span class="hlt">grazing</span> influence within- and between-<span class="hlt">grazing</span> season dietary quality of yearling steers in shortgrass steppe?</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Pulse-<span class="hlt">grazing</span>, high stock density with short <span class="hlt">grazing</span> periods (weeks) followed by long (months to > 1 year) rest periods, is a <span class="hlt">grazing</span> management strategy posited to decrease preferential selection by cattle and increase utilization of forage, but influences on dietary quality of <span class="hlt">grazing</span> animals in s...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS23A1983H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS23A1983H"><span><span class="hlt">Zooplankton</span> Responses to Low-Oxygen Condition upon a Shallow Oxygen Minimum Zone in the Upwelling Region off Chile</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hidalgo, P.; Escribano, R.</p> <p>2015-12-01</p> <p>A shallow oxygen minimum zone (OMZ) is a critical component in the coastal upwelling ecosystem off Chile. This OMZ causes oxygen-deficient water entering the photic layer and affecting plankton communities having low tolerance to hypoxia. Variable, and usually species-dependent, responses of <span class="hlt">zooplankton</span> to hypoxia condition can be found. Most dominant species avoid hypoxia by restricting their vertical distribution, while others can temporarily enter and even spent part of their life cycle within the OMZ. Whatever the case, low-oxygen conditions appear to affect virtually all vital <span class="hlt">rates</span> of <span class="hlt">zooplankton</span>, such as mortality, fecundity, development and growth and metabolism, and early developmental stages seem more sensitive, with significant consequences for population and community dynamics. For most study cases, these effects are negative at individual and population levels. Observations and predictions upon increasing upwelling intensity over the last 20-30 years indicate a gradual shoaling of the OMZ, and so that an expected enhancement of these negative effects of hypoxia on the <span class="hlt">zooplankton</span> community. Unknown processes of adaptation and community-structure adjustments are expected to take place with uncertain consequences for the food web of this highly productive eastern boundary current ecosystem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22203999','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22203999"><span>Bacterial bioluminescence as a lure for marine <span class="hlt">zooplankton</span> and fish.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zarubin, Margarita; Belkin, Shimshon; Ionescu, Michael; Genin, Amatzia</p> <p>2012-01-17</p> <p>The benefits of bioluminescence for nonsymbiotic marine bacteria have not been elucidated fully. One of the most commonly cited explanations, proposed more than 30 y ago, is that bioluminescence augments the propagation and dispersal of bacteria by attracting fish to consume the luminous material. This hypothesis, based mostly on the prevalence of luminous bacteria in fish guts, has not been tested experimentally. Here we show that <span class="hlt">zooplankton</span> that contacts and feeds on the luminescent bacterium Photobacterium leiognathi starts to glow, and demonstrate by video recordings that glowing individuals are highly vulnerable to predation by nocturnal fish. Glowing bacteria thereby are transferred to the nutritious guts of fish and <span class="hlt">zooplankton</span>, where they survive digestion and gain effective means for growth and dispersal. Using bioluminescence as bait appears to be highly beneficial for marine bacteria, especially in food-deprived environments of the deep sea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3271926','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3271926"><span>Bacterial bioluminescence as a lure for marine <span class="hlt">zooplankton</span> and fish</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zarubin, Margarita; Belkin, Shimshon; Ionescu, Michael; Genin, Amatzia</p> <p>2012-01-01</p> <p>The benefits of bioluminescence for nonsymbiotic marine bacteria have not been elucidated fully. One of the most commonly cited explanations, proposed more than 30 y ago, is that bioluminescence augments the propagation and dispersal of bacteria by attracting fish to consume the luminous material. This hypothesis, based mostly on the prevalence of luminous bacteria in fish guts, has not been tested experimentally. Here we show that <span class="hlt">zooplankton</span> that contacts and feeds on the luminescent bacterium Photobacterium leiognathi starts to glow, and demonstrate by video recordings that glowing individuals are highly vulnerable to predation by nocturnal fish. Glowing bacteria thereby are transferred to the nutritious guts of fish and <span class="hlt">zooplankton</span>, where they survive digestion and gain effective means for growth and dispersal. Using bioluminescence as bait appears to be highly beneficial for marine bacteria, especially in food-deprived environments of the deep sea. PMID:22203999</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/42046','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/42046"><span>Riparian-fisheries habitat responses to late spring cattle <span class="hlt">grazing</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Warren P. Clary; John W. Kinney</p> <p>2000-01-01</p> <p>A <span class="hlt">grazing</span> study was conducted on a cold, mountain meadow riparian system in central Idaho in response to cattle <span class="hlt">grazing</span>-salmonid fisheries conflicts. Six pastures were established along a 3rd order, 2 to 3 m wide stream to study the effects on fisheries habitat of no <span class="hlt">grazing</span>, light <span class="hlt">grazing</span> (20 to 25% use), and medium <span class="hlt">grazing</span> (35 to 50%) during late June. Most...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70011713','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70011713"><span><span class="hlt">Zooplankton</span> fecal pellets link fossil fuel and phosphate deposits</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Porter, K.G.; Robbins, E.I.</p> <p>1981-01-01</p> <p>Fossil <span class="hlt">zooplankton</span> fecal pellets found in thinly bedded marine and lacustrine black shales associated with phosphate, oil, and coal deposits, link the deposition of organic matter and biologically associated minerals with planktonic ecosystems. The black shales were probably formed in the anoxic basins of coastal marine waters, inland seas, and rift valley lakes where high productivity was supported by runoff, upwelling, and outwelling. Copyright ?? 1981 AAAS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA630079','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA630079"><span>Development and Applications of Technology for Sensing <span class="hlt">Zooplankton</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2003-09-30</p> <p><span class="hlt">zooplankton</span>-like particles. WORK COMPLETED In support of our first objective, in prior years we occupied sites in both East and West Sound at Orcas ...Island in northern Puget Sound , WA. We have also made deployments at four sites on open linear coasts, including one just north of Oceanside, CA (Red...layers. Multi-static, multi-frequency methods Most active bioacoustical methods in oceanography exclusively utilize the sound that is scattered</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.6989J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.6989J"><span>Impact of <span class="hlt">grazing</span> on carbon balance of a Belgian grassland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jérôme, Elisabeth; Beckers, Yves; Bodson, Bernard; Moureaux, Christine; Dumortier, Pierre; Beekkerk van Ruth, Joran; Aubinet, Marc</p> <p>2013-04-01</p> <p>This work analyzes the impact of <span class="hlt">grazing</span> on the carbon balance of a grassland <span class="hlt">grazed</span> by the Belgian Blue breed of cattle. The research was run at the Dorinne terrestrial observatory (DTO). The experimental site is a permanent grassland of ca. 4.2 ha located in the Belgian Condroz (50° 18' 44" N; 4° 58' 07" E; 248 m asl.). Other studies are conducted at the DTO including measurements of methane (CH4) and nitrous oxide fluxes (Dumortier et al., Geophysical Research Abstracts, Vol. 15, EGU2013-2083-1, 2013; Beekkerk van Ruth et al., Geophysical Research Abstracts, Vol. 15, EGU2013-3211, 2013, respectively). Grassland carbon budget (Net Biome Productivity, NBP) was calculated from Net Ecosystem Exchange (NEE) measured by eddy covariance by taking imports and exports of organic C and losses of carbon as CH4 into account. After 2 years of measurements (May 2010 - May 2012), the grassland behaved on average as a CO2 source (NEE = 73 ±31 g C m-2 y-1). After inclusion of all the C inputs and outputs the site was closed to equilibrium (NBP = 23 ±34 g C m-2 y-1). To analyze the impact of <span class="hlt">grazing</span> on CO2 fluxes, we studied the temporal evolution of gross maximal photosynthetic capacity GPPmax and dark respiration Rd (deduced from the response of daytime fluxes to radiation over 5-day windows). We calculated GPPmax and Rd variation between the end and the beginning of <span class="hlt">grazing</span> or non-<span class="hlt">grazing</span> periods (ΔGPPmax and ΔRd, respectively). We observed a significant decrease of GPPmax during <span class="hlt">grazing</span> periods and measured a ΔGPPmax dependence on the average stocking <span class="hlt">rate</span>. This allows us to quantify the assimilation reduction due to grass consumption by cattle. On the contrary, no Rd decrease was observed during <span class="hlt">grazing</span> periods. Moreover, we found that cumulated monthly NEE increased significantly with the average stocking <span class="hlt">rate</span>. In addition, a confinement experiment was carried out in order to analyze livestock contribution to Total Ecosystem Respiration. Each experiment extended over</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986DSRA...33.1729Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986DSRA...33.1729Y"><span>Small-scale <span class="hlt">zooplankton</span> aggregations at the front of a Kuroshio warm-core ring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamamoto, Tamiji; Nishizawa, Satoshi</p> <p>1986-11-01</p> <p>A Longhurst-Hardy Plankton Recorder was used to study the small-scale <span class="hlt">zooplankton</span> distribution across the front of a Kuroshio warm-core ring in June 1979. <span class="hlt">Zooplankton</span> were strongly aggregated in the frontal region; patches of <span class="hlt">zooplankton</span> and phytoplankton were spatially separated. A major part of the <span class="hlt">zooplankton</span> assemblage consisted of neritic forms such as cladocerans and indicator species of the cold Oyashio water. This implies that lateral entrainment of coastal waters, which is directly influenced by the Oyashio, was an important factor in the formation of the aggregations at the Kuroshio warm-core ring front. Variation in the distribution of abundance peaks of individual <span class="hlt">zooplankton</span> species was also observed. Futhermore, <span class="hlt">zooplankton</span> showed more intensive non-randomness (aggregation) than phytoplankton and non-motile euphausiid's eggs. Thus, biological processes, such as motility and prey-predator interaction, also appeared to be regulating the patchiness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27510848','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27510848"><span>Terrestrial carbohydrates support freshwater <span class="hlt">zooplankton</span> during phytoplankton deficiency.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Taipale, Sami J; Galloway, Aaron W E; Aalto, Sanni L; Kahilainen, Kimmo K; Strandberg, Ursula; Kankaala, Paula</p> <p>2016-08-11</p> <p>Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, <span class="hlt">zooplankton</span> (Daphnia magna) can benefit from terrestrial particulate organic matter by using terrestrial-origin carbohydrates for energy and sparing essential fatty acids and amino acids for somatic growth and reproduction. Assimilated terrestrial-origin fatty acids from shoreline reed particles exceeded available diet, indicating that Daphnia may convert a part of their dietary carbohydrates to saturated fatty acids. This conversion was not observed with birch leaf diets, which had lower carbohydrate content. Subsequent analysis of 21 boreal and subarctic lakes showed that diet of herbivorous <span class="hlt">zooplankton</span> is mainly based on high-quality phytoplankton rich in essential polyunsaturated fatty acids. The proportion of low-quality diets (bacteria and terrestrial particulate organic matter) was <28% of the assimilated carbon. Taken collectively, the incorporation of terrestrial carbon into <span class="hlt">zooplankton</span> was not directly related to the concentration of terrestrial organic matter in experiments or lakes, but rather to the low availability of phytoplankton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4980614','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4980614"><span>Terrestrial carbohydrates support freshwater <span class="hlt">zooplankton</span> during phytoplankton deficiency</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Taipale, Sami J.; Galloway, Aaron W. E.; Aalto, Sanni L.; Kahilainen, Kimmo K.; Strandberg, Ursula; Kankaala, Paula</p> <p>2016-01-01</p> <p>Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, <span class="hlt">zooplankton</span> (Daphnia magna) can benefit from terrestrial particulate organic matter by using terrestrial-origin carbohydrates for energy and sparing essential fatty acids and amino acids for somatic growth and reproduction. Assimilated terrestrial-origin fatty acids from shoreline reed particles exceeded available diet, indicating that Daphnia may convert a part of their dietary carbohydrates to saturated fatty acids. This conversion was not observed with birch leaf diets, which had lower carbohydrate content. Subsequent analysis of 21 boreal and subarctic lakes showed that diet of herbivorous <span class="hlt">zooplankton</span> is mainly based on high-quality phytoplankton rich in essential polyunsaturated fatty acids. The proportion of low-quality diets (bacteria and terrestrial particulate organic matter) was <28% of the assimilated carbon. Taken collectively, the incorporation of terrestrial carbon into <span class="hlt">zooplankton</span> was not directly related to the concentration of terrestrial organic matter in experiments or lakes, but rather to the low availability of phytoplankton. PMID:27510848</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1917930C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1917930C"><span>SEAPODYM-LTL: a parsimonious <span class="hlt">zooplankton</span> dynamic biomass model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Conchon, Anna; Lehodey, Patrick; Gehlen, Marion; Titaud, Olivier; Senina, Inna; Séférian, Roland</p> <p>2017-04-01</p> <p>Mesozooplankton organisms are of critical importance for the understanding of early life history of most fish stocks, as well as the nutrient cycles in the ocean. Ongoing climate change and the need for improved approaches to the management of living marine resources has driven recent advances in <span class="hlt">zooplankton</span> modelling. The classical modeling approach tends to describe the whole biogeochemical and plankton cycle with increasing complexity. We propose here a different and parsimonious <span class="hlt">zooplankton</span> dynamic biomass model (SEAPODYM-LTL) that is cost efficient and can be advantageously coupled with primary production estimated either from satellite derived ocean color data or biogeochemical models. In addition, the adjoint code of the model is developed allowing a robust optimization approach for estimating the few parameters of the model. In this study, we run the first optimization experiments using a global database of climatological <span class="hlt">zooplankton</span> biomass data and we make a comparative analysis to assess the importance of resolution and primary production inputs on model fit to observations. We also compare SEAPODYM-LTL outputs to those produced by a more complex biogeochemical model (PISCES) but sharing the same physical forcings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5061914','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5061914"><span>Reduced fine-scale spatial genetic structure in <span class="hlt">grazed</span> populations of Dianthus carthusianorum</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rico, Y; Wagner, H H</p> <p>2016-01-01</p> <p>Strong spatial genetic structure in plant populations can increase homozygosity, reducing genetic diversity and adaptive potential. The strength of spatial genetic structure largely depends on <span class="hlt">rates</span> of seed dispersal and pollen flow. Seeds without dispersal adaptations are likely to be dispersed over short distances within the vicinity of the mother plant, resulting in spatial clustering of related genotypes (fine-scale spatial genetic structure, hereafter spatial genetic structure (SGS)). However, primary seed dispersal by zoochory can promote effective dispersal, increasing the mixing of seeds and influencing SGS within plant populations. In this study, we investigated the effects of seed dispersal by rotational sheep <span class="hlt">grazing</span> on the strength of SGS and genetic diversity using 11 nuclear microsatellites for 49 populations of the calcareous grassland forb Dianthus carthusianorum. Populations connected by rotational sheep <span class="hlt">grazing</span> showed significantly weaker SGS and higher genetic diversity than populations in ungrazed grasslands. Independent of <span class="hlt">grazing</span> treatment, small populations showed significantly stronger SGS and lower genetic diversity than larger populations, likely due to genetic drift. A lack of significant differences in the strength of SGS and genetic diversity between populations that were recently colonized and pre-existing populations suggested that populations colonized after the reintroduction of rotational sheep <span class="hlt">grazing</span> were likely founded by colonists from diverse source populations. We conclude that dispersal by rotational sheep <span class="hlt">grazing</span> has the potential to considerably reduce SGS within D. carthusianorum populations. Our study highlights the effectiveness of landscape management by rotational sheep <span class="hlt">grazing</span> to importantly reduce genetic structure at local scales within restored plant populations. PMID:27381322</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27381322','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27381322"><span>Reduced fine-scale spatial genetic structure in <span class="hlt">grazed</span> populations of Dianthus carthusianorum.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rico, Y; Wagner, H H</p> <p>2016-11-01</p> <p>Strong spatial genetic structure in plant populations can increase homozygosity, reducing genetic diversity and adaptive potential. The strength of spatial genetic structure largely depends on <span class="hlt">rates</span> of seed dispersal and pollen flow. Seeds without dispersal adaptations are likely to be dispersed over short distances within the vicinity of the mother plant, resulting in spatial clustering of related genotypes (fine-scale spatial genetic structure, hereafter spatial genetic structure (SGS)). However, primary seed dispersal by zoochory can promote effective dispersal, increasing the mixing of seeds and influencing SGS within plant populations. In this study, we investigated the effects of seed dispersal by rotational sheep <span class="hlt">grazing</span> on the strength of SGS and genetic diversity using 11 nuclear microsatellites for 49 populations of the calcareous grassland forb Dianthus carthusianorum. Populations connected by rotational sheep <span class="hlt">grazing</span> showed significantly weaker SGS and higher genetic diversity than populations in ungrazed grasslands. Independent of <span class="hlt">grazing</span> treatment, small populations showed significantly stronger SGS and lower genetic diversity than larger populations, likely due to genetic drift. A lack of significant differences in the strength of SGS and genetic diversity between populations that were recently colonized and pre-existing populations suggested that populations colonized after the reintroduction of rotational sheep <span class="hlt">grazing</span> were likely founded by colonists from diverse source populations. We conclude that dispersal by rotational sheep <span class="hlt">grazing</span> has the potential to considerably reduce SGS within D. carthusianorum populations. Our study highlights the effectiveness of landscape management by rotational sheep <span class="hlt">grazing</span> to importantly reduce genetic structure at local scales within restored plant populations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......297B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......297B"><span>Material properties of <span class="hlt">zooplankton</span> and nekton from the California current</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Becker, Kaylyn</p> <p></p> <p>This study measured the material properties of <span class="hlt">zooplankton</span>, Pacific hake (Merluccius productus), Humboldt squid (Dosidicus gigas), and two species of myctophids (Symbolophorus californiensis and Diaphus theta) collected from the California Current ecosystem. The density contrast (g) was measured for euphausiids, decapods (Sergestes similis), amphipods (Primno macropa, Phronima sp., and Hyperiid spp.), siphonophore bracts, chaetognaths, larval fish, crab megalopae, larval squid, and medusae. Morphometric data (length, width, and height) were collected for these taxa. Density contrasts varied within and between <span class="hlt">zooplankton</span> taxa. The mean and standard deviation for euphausiid density contrast were 1.059 +/- 0.009. Relationships between <span class="hlt">zooplankton</span> density contrast and morphometric measurements, geographic location, and environmental conditions were investigated. Site had a significant effect on euphausiid density contrast. Density contrasts of euphausiids collected in the same geographic area approximately 4-10 days apart were significantly higher (p < 0.001). Sound speed contrast (h) was measured for euphausiids and pelagic decapods (S. similis) and it varied between taxa. The mean and standard deviation for euphausiid sound speed were 1.019 +/- 0.009. Euphausiid mass was calculated from density measurements and volume, and a relationship between euphausiid mass and length was produced. We determined that euphausiid from volumes could be accurately estimated two dimensional measurements of animal body shape, and that biomass (or biovolume) could be accurately calculated from digital photographs of animals. Density contrast (g) was measured for <span class="hlt">zooplankton</span>, pieces of hake flesh, myctophid flesh, and of the following Humboldt squid body parts: mantle, arms, tentacle, braincase, eyes, pen, and beak. The density contrasts varied within and between fish taxa, as well as among squid body parts. Effects of animal length and environmental conditions on nekton density</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025422','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025422"><span>Selenium in San Francisco Bay <span class="hlt">zooplankton</span>: Potential effects of hydrodynamics and food web interactions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Purkerson, D.G.; Doblin, M.A.; Bollens, S.M.; Luoma, S.N.; Cutter, G.A.</p> <p>2003-01-01</p> <p>The potential toxicity of elevated selenium (Se) concentrations in aquatic ecosystems has stimulated efforts to measure Se concentrations in benthos, nekton, and waterfowl in San Francisco Bay (SF Bay). In September 1998, we initiated a 14 mo field study to determine the concentration of Se in SF Bay <span class="hlt">zooplankton</span>, which play a major role in the Bay food web, but which have not previously been studied with respect to Se. Monthly vertical plankton tows were collected at several stations throughout SF Bay, and <span class="hlt">zooplankton</span> were separated into two operationally defined size classes for Se analyses: 73-2,000 ??m, and ???2,000 ??m. Selenium values ranged 1.02-6.07 ??g Se g-1 dry weight. No spatial differences in <span class="hlt">zooplankton</span> Se concentrations were found. However, there were inter- and intra-annual differences. <span class="hlt">Zooplankton</span> Se concentrations were enriched in the North Bay in Fall 1999 when compared to other seasons and locations within and outside SF Bay. The abundance and biovolume of the <span class="hlt">zooplankton</span> community varied spatially between stations, but not seasonally within each station. Smaller herbivorous-omnivorous <span class="hlt">zooplankton</span> had higher Se concentrations than larger omnivorous-carnivorous <span class="hlt">zooplankton</span>. Selenium concentrations in <span class="hlt">zooplankton</span> were negatively correlated with the proportion of total copepod biovolume comprising the large carnivorous copepod Tortanus dextrilobatus, but positively correlated with the proportion of copepod biovolume comprising smaller copepods of the family Oithonidae, suggesting an important role of trophic level and size in regulating <span class="hlt">zooplankton</span> Se concentrations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29242669','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29242669"><span>Crustacean <span class="hlt">zooplankton</span> release copious amounts of dissolved organic matter as taurine in the ocean.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Clifford, Elisabeth L; Hansell, Dennis A; Varela, Marta M; Nieto-Cid, Mar; Herndl, Gerhard J; Sintes, Eva</p> <p>2017-11-01</p> <p>Taurine (Tau), an amino acid-like compound, is present in almost all marine metazoans including crustacean <span class="hlt">zooplankton</span>. It plays an important physiological role in these organisms and is released into the ambient water throughout their life cycle. However, limited information is available on the release <span class="hlt">rates</span> by marine organisms, the concentrations and turnover of Tau in the ocean. We determined dissolved free Tau concentrations throughout the water column and its release by abundant crustacean mesozooplankton at two open ocean sites (Gulf of Alaska and North Atlantic). At both locations, the concentrations of dissolved free Tau were in the low nM range (up to 15.7 nM) in epipelagic waters, declining sharply in the mesopelagic to about 0.2 nM and remaining fairly stable throughout the bathypelagic waters. Pacific amphipod-copepod assemblages exhibited lower dissolved free Tau release <span class="hlt">rates</span> per unit biomass (0.8 ± 0.4 μmol g -1 C-biomass h -1 ) than Atlantic copepods (ranging between 1.3 ± 0.4 μmol g -1 C-biomass h -1 and 9.5 ± 2.1 μmol g -1 C-biomass h -1 ), in agreement with the well-documented inverse relationship between biomass-normalized excretion <span class="hlt">rates</span> and body size. Our results indicate that crustacean <span class="hlt">zooplankton</span> might contribute significantly to the dissolved organic matter flux in marine ecosystems via dissolved free Tau release. Based on the release <span class="hlt">rates</span> and assuming steady state dissolved free Tau concentrations, turnover times of dissolved free Tau range from 0.05 d to 2.3 d in the upper water column and are therefore similar to those of dissolved free amino acids. This rapid turnover indicates that dissolved free Tau is efficiently consumed in oceanic waters, most likely by heterotrophic bacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME44A0846F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME44A0846F"><span>Molecular Quantification of <span class="hlt">Zooplankton</span> Gut Content: The Case For qPCR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frischer, M. E.; Walters, T. L.; Gibson, D. M.; Nejstgaard, J. C.; Troedsson, C.</p> <p>2016-02-01</p> <p>The ability to obtain information about feeding selectivity and <span class="hlt">rates</span> in situ for <span class="hlt">zooplankton</span> is vital for understanding the mechanisms structuring marine ecosystems. However, directly estimating feeding selection and <span class="hlt">rates</span> of <span class="hlt">zooplankton</span>, without bias, associated with culturing conditions has been notoriously difficult. A potential approach for addressing this problem is to target prey-specific DNA as a marker for prey ingestion and selection. In this study we report the development of a differential length amplification quantitative PCR (dla-qPCR) assay targeting the 18S rRNA gene to validate the use of a DNA-based approach to quantify consumption of specific plankton prey by the pelagic tunicate (doliolid) Dolioletta gegenbauri. Compared to copepods and other marine animals, the digestion of prey genomic DNA inside the gut of doliolids is low. This method minimizes potential underestimations, and therefore allows prey DNA to be used as an effective indicator of prey consumption. We also present an initial application of a qPCR-assay to estimate consumption of specific prey species on the southeastern continental shelf of the U.S., where doliolids stochastically bloom in response to upwelling events. Estimated feeding <span class="hlt">rates</span>, based on qPCR, were in the same range as those estimated from clearance <span class="hlt">rates</span> in laboratory feeding studies. In the field, consumption of specific prey, including the centric diatom Thalassiosira spp. was detected in the gut of wild caught D. gegenbauri at the levels consistent with their abundance in the water column at the time of collection. Thus, both experimental and field investigations support the hypothesis that a qPCR approach will be useful for the quantitative investigation of the in situ diet of D. gegenbauri without introduced bias' associated with cultivation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=346744','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=346744"><span><span class="hlt">Grazing</span> history effects on rangeland biomass, cover and diversity responses to fire and <span class="hlt">grazing</span> utilization</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Exclusion of large grazers from rangelands that evolved with significant <span class="hlt">grazing</span> pressure can alter natural processes and may have legacy effects by changing magnitude or direction of community responses to subsequent disturbance. Three moderately <span class="hlt">grazed</span> pastures were paired with 12-ha areas that h...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=262319','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=262319"><span>Protistan <span class="hlt">Grazing</span> Analysis by Flow Cytometry Using Prey Labeled by In Vivo Expression of Fluorescent Proteins</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fu, Yutao; O'Kelly, Charles; Sieracki, Michael; Distel, Daniel L.</p> <p>2003-01-01</p> <p>Selective <span class="hlt">grazing</span> by protists can profoundly influence bacterial community structure, and yet direct, quantitative observation of <span class="hlt">grazing</span> selectivity has been difficult to achieve. In this investigation, flow cytometry was used to study <span class="hlt">grazing</span> by the marine heterotrophic flagellate Paraphysomonas imperforata on live bacterial cells genetically modified to express the fluorescent protein markers green fluorescent protein (GFP) and red fluorescent protein (RFP). Broad-host-range plasmids were constructed that express fluorescent proteins in three bacterial prey species, Escherichia coli, Enterobacter aerogenes, and Pseudomonas putida. Micromonas pusilla, an alga with red autofluorescence, was also used as prey. Predator-prey interactions were quantified by using a FACScan flow cytometer and analyzed by using a Perl program described here. <span class="hlt">Grazing</span> preference of P. imperforata was influenced by prey type, size, and condition. In competitive feeding trials, P. imperforata consumed algal prey at significantly lower <span class="hlt">rates</span> than FP (fluorescent protein)-labeled bacteria of similar or different size. Within-species size selection was also observed, but only for P. putida, the largest prey species examined; smaller cells of P. putida were <span class="hlt">grazed</span> preferentially. No significant difference in clearance <span class="hlt">rate</span> was observed between GFP- and RFP-labeled strains of the same prey species or between wild-type and GFP-labeled strains. In contrast, the common chemical staining method, 5-(4,6-dichloro-triazin-2-yl)-amino fluorescein hydrochloride, depressed clearance <span class="hlt">rates</span> for bacterial prey compared to unlabeled or RFP-labeled cells. PMID:14602649</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29859439','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29859439"><span>Retention and characteristics of microplastics in natural <span class="hlt">zooplankton</span> taxa from the East China Sea.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Xiaoxia; Liu, Tao; Zhu, Mingliang; Liang, Junhua; Zhao, Yongfang; Zhang, Bo</p> <p>2018-05-30</p> <p>The ubiquitous presence and persistence of microplastics (MPs) in aquatic environments have become of particular concern in recent years. Biological interactions are among the key processes that affect the impact and fate of MPs in the oceans. <span class="hlt">Zooplankton</span> is one of the most sensitive taxa because their prey is approximately the same size as MPs. However, the status of MPs in <span class="hlt">zooplankton</span> within natural marine environments remains largely unknown. By focusing on <span class="hlt">zooplankton</span> in the East China Sea, the characteristics, bioaccumulated concentration, and retention of MPs for 10 <span class="hlt">zooplankton</span> groups were systematically studied. Three types of MPs were found in <span class="hlt">zooplankton</span>: fibres, pellets, and fragments. The fibres (54.6%) were more common than the other two types. The average lengths of the fibres, pellets, and fragments were 295.2 ± 348.6 μm, 20.3 ± 11.0 μm, and 82.4 ± 80.5 μm, respectively. Nineteen polymers were detected in the <span class="hlt">zooplankton</span> via the Thermo Scientific Nicolet iN10 Infrared Microscope. Polymerized oxidized organic material and polyester were dominant, accounting for 35.9% and 25.6% of the polymers, respectively. The bioaccumulated concentration of MPs in the 10 <span class="hlt">zooplankton</span> taxa varied from 0.13 pieces/<span class="hlt">zooplankton</span> for Copepoda to 0.35 pieces/<span class="hlt">zooplankton</span> for Pteropoda. The bioaccumulated concentration was negatively correlated with the abundance of <span class="hlt">zooplankton</span>, showing a significant biological dilution effect. The bioaccumulated concentration was also influenced by the feeding mode of <span class="hlt">zooplankton</span>, showing a trend of omnivorous > carnivorous > herbivorous. High retention of MPs was found in the <span class="hlt">zooplankton</span> community of the East China Sea, achieving 19.7 ± 22.4 pieces/m 3 . This is much higher than the MP retention in <span class="hlt">zooplankton</span> from other reported sea areas. By revealing the characteristics and retention of MPs in the natural <span class="hlt">zooplankton</span> taxa from the East China Sea, this research identified the influence that MPs have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29727853','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29727853"><span>Strategic <span class="hlt">grazing</span> management towards sustainable intensification at tropical pasture-based dairy systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Congio, Guilhermo F S; Batalha, Camila D A; Chiavegato, Marília B; Berndt, Alexandre; Oliveira, Patrícia P A; Frighetto, Rosa T S; Maxwell, Thomas M R; Gregorini, Pablo; Da Silva, Sila C</p> <p>2018-05-01</p> <p>Agricultural systems are responsible for environmental impacts that can be mitigated through the adoption of more sustainable principles. Our objective was to investigate the influence of two pre-<span class="hlt">grazing</span> targets (95% and maximum canopy light interception during pasture regrowth; LI 95% and LI Max , respectively) on sward structure and herbage nutritive value of elephant grass cv. Cameroon, and dry matter intake (DMI), milk yield, stocking <span class="hlt">rate</span>, enteric methane (CH 4 ) emissions by Holstein × Jersey dairy cows. We hypothesized that <span class="hlt">grazing</span> strategies modifying the sward structure of elephant grass (Pennisetum purpureum Schum.) improves nutritive value of herbage, increasing DMI and reducing intensity of enteric CH 4 emissions, providing environmental and productivity benefits to tropical pasture-based dairy systems. Results indicated that pre-sward surface height was greater for LI Max (≈135 cm) than LI 95% (≈100 cm) and can be used as a reliable field guide for monitoring sward structure. <span class="hlt">Grazing</span> management based on LI 95% criteria improved herbage nutritive value and <span class="hlt">grazing</span> efficiency, allowing greater DMI, milk yield and stocking <span class="hlt">rate</span> by dairy cows. Daily enteric CH 4 emission was not affected; however, cows <span class="hlt">grazing</span> elephant grass at LI 95% were more efficient and emitted 21% less CH 4 /kg of milk yield and 18% less CH 4 /kg of DMI. The 51% increase in milk yield per hectare overcame the 29% increase in enteric CH 4 emissions per hectare in LI 95% <span class="hlt">grazing</span> management. Thereby the same resource allocation resulted in a 16% mitigation of the main greenhouse gas from pasture-based dairy systems. Overall, strategic <span class="hlt">grazing</span> management is an environmental friendly practice that improves use efficiency of allocated resources through optimization of processes evolving plant, ruminant and their interface, and enhances milk production efficiency of tropical pasture-based systems. Copyright © 2018 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSPP24A0542H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSPP24A0542H"><span>Mingled Mortality: the Interplay Between Protist <span class="hlt">Grazing</span> and Viral Lysis on Emiliania huxleyi Cell Fate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harvey, E.; Bidle, K. D.; Johnson, M. D.</p> <p>2016-02-01</p> <p>The coccolithophore, Emiliania huxleyi plays a prominent role in global carbon cycling, as their calcite coccoliths account for a third of all oceanic calcite production. Mortality due to <span class="hlt">grazing</span> by microzooplankton is the largest contributor to phytoplankton loss in the marine environment. However, viral infection of E. huxleyi is now thought to be as important as <span class="hlt">grazing</span> pressure in contributing to its mortality. To understand the influence of viral infection on <span class="hlt">grazing</span> dynamics, we examined the response of the dinoflagellate predator, Oxyrrhis marina to E. huxleyi infected with four different strains of the E. huxleyi virus (EhV). <span class="hlt">Grazing</span> <span class="hlt">rate</span> was significantly slower on E. huxleyi cultures that had been infected for 48 h compared to an uninfected control and this reduction in <span class="hlt">grazing</span> <span class="hlt">rate</span> was dependent on the strain identity of infecting EhVs. Additional experimentation indicated that <span class="hlt">grazing</span> was the primary source of E. huxleyi loss ( 78-98%) during the first 24 h of exposure to both predator and virus. However, as viral infection progressed into the late lytic phase (48 h hour post infection), the relative contribution of <span class="hlt">grazing</span> to total E. huxleyi mortality decreased ( 5-60%). These results suggest that mortality is partitioned along a gradient between predator-based consumption and virus-induced cell lysis, dependent on the timing of infection. Deciphering the relative importance and interactive nature of these alga-predator-viral interactions will help to elucidate the mechanisms that drive bulk measurements of phytoplankton loss, a necessary understanding to interpret and predict phytoplankton population dynamics and associated biogeochemical cycling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036191','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036191"><span>Planktivory in the changing Lake Huron <span class="hlt">zooplankton</span> community: Bythotrephes consumption exceeds that of Mysis and fish</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bunnell, D.B.; Hunter, R. Douglas; Warner, D.M.; Chriscinske, M.A.; Roseman, E.F.</p> <p>2011-01-01</p> <p>Oligotrophic lakes are generally dominated by calanoid copepods because of their competitive advantage over cladocerans at low prey densities. Planktivory also can alter <span class="hlt">zooplankton</span> community structure. We sought to understand the role of planktivory in driving recent changes to the <span class="hlt">zooplankton</span> community of Lake Huron, a large oligotrophic lake on the border of Canada and the United States. We tested the hypothesis that excessive predation by fish (rainbow smelt Osmerus mordax, bloater Coregonus hoyi) and invertebrates (Mysis relicta, Bythotrephes longimanus) had driven observed declines in cladoceran and cyclopoid copepod biomass between 2002 and 2007. We used a field sampling and bioenergetics modelling approach to generate estimates of daily consumption by planktivores at two 91-m depth sites in northern Lake Huron, U.S.A., for each month, May-October 2007. Daily consumption was compared to daily <span class="hlt">zooplankton</span> production. Bythotrephes was the dominant planktivore and estimated to have eaten 78% of all <span class="hlt">zooplankton</span> consumed. Bythotrephes consumption exceeded total <span class="hlt">zooplankton</span> production between July and October. Mysis consumed 19% of all the <span class="hlt">zooplankton</span> consumed and exceeded <span class="hlt">zooplankton</span> production in October. Consumption by fish was relatively unimportant - eating only 3% of all <span class="hlt">zooplankton</span> consumed. Because Bythotrephes was so important, we explored other consumption estimation methods that predict lower Bythotrephes consumption. Under this scenario, Mysis was the most important planktivore, and Bythotrephes consumption exceeded <span class="hlt">zooplankton</span> production only in August. Our results provide no support for the hypothesis that excessive fish consumption directly contributed to the decline of cladocerans and cyclopoid copepods in Lake Huron. Rather, they highlight the importance of invertebrate planktivores in structuring <span class="hlt">zooplankton</span> communities, especially for those foods webs that have both Bythotrephes and Mysis. Together, these species occupy the epi-, meta- and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=227848','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=227848"><span>Streambank Erosion from <span class="hlt">Grazed</span> Pastures, Grass Filters and Forest Buffers Over a Six-Year Period</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>In agricultural landscapes, streambank erosion, as a source of non-point water pollution, is one of the major contributors to stream habitat degradation. Streambank erosion <span class="hlt">rates</span> from riparian forest buffers, grass filters and <span class="hlt">grazed</span> pastures (stocking <span class="hlt">rates</span> ranged from 0.23 to 1.15 cow-days ha-1 m-...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008BGD.....5....1A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008BGD.....5....1A"><span>Dissolution of coccolithophorid calcite by microzooplankton and copepod <span class="hlt">grazing</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Antia, A. N.; Suffrian, K.; Holste, L.; Müller, M. N.; Nejstgaard, J. C.; Simonelli, P.; Carotenuto, Y.; Putzeys, S.</p> <p>2008-01-01</p> <p>Independent of the ongoing acidification of surface seawater, the majority of the calcium carbonate produced in the pelagial is dissolved by natural processes above the lysocline. We investigate to what extent <span class="hlt">grazing</span> and passage of coccolithophorids through the guts of copepods and the food vacuoles of microzooplankton contribute to calcite dissolution. In laboratory experiments where the coccolithophorid Emiliania huxleyi was fed to the rotifer Brachionus plicatilis, the heterotrophic flagellate Oxyrrhis marina and the copepod Acartia tonsa, calcite dissolution <span class="hlt">rates</span> of 45-55%, 37-53% and 5-22% of ingested calcite were found. We ascribe higher loss <span class="hlt">rates</span> in microzooplankton food vacuoles as compared to copepod guts to the strongly acidic digestion and the individual packaging of algal cells. In further experiments, specific <span class="hlt">rates</span> of calcification and calcite dissolution were also measured in natural populations during the PeECE III mesocosm study under differing ambient pCO2 concentrations. Microzooplankton <span class="hlt">grazing</span> accounted for between 27 and 70% of the dynamic calcite stock being lost per day, with no measurable effect of CO2 treatment. These measured calcite dissolution <span class="hlt">rates</span> indicate that dissolution of calcite in the guts of microzooplankton and copepods can account for the calcite losses calculated for the global ocean using budget and model estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27366650','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27366650"><span>Towards evenly distributed <span class="hlt">grazing</span> patterns: including social context in sheep management strategies.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>di Virgilio, Agustina; Morales, Juan Manuel</p> <p>2016-01-01</p> <p> are common practices to increase flock productivity, we are proposing an alternative that employs behavioural interactions in heterogeneous flocks to generate more evenly distributed <span class="hlt">grazing</span> patterns. This practice can be combined with other practices such as rotational <span class="hlt">grazing</span> and guardian dogs (to decrease mortality levels that may be generated by sheep <span class="hlt">grazing</span> on more risky habitats). This does not imply any modifications of livestock stocking <span class="hlt">rates</span> and densities or any additional investments for labour and materials. Considering livestock behaviour is critical for the design of sustainable management practices that balance landscape conservation and livestock productivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4924134','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4924134"><span>Towards evenly distributed <span class="hlt">grazing</span> patterns: including social context in sheep management strategies</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Morales, Juan Manuel</p> <p>2016-01-01</p> <p> classes are common practices to increase flock productivity, we are proposing an alternative that employs behavioural interactions in heterogeneous flocks to generate more evenly distributed <span class="hlt">grazing</span> patterns. This practice can be combined with other practices such as rotational <span class="hlt">grazing</span> and guardian dogs (to decrease mortality levels that may be generated by sheep <span class="hlt">grazing</span> on more risky habitats). This does not imply any modifications of livestock stocking <span class="hlt">rates</span> and densities or any additional investments for labour and materials. Considering livestock behaviour is critical for the design of sustainable management practices that balance landscape conservation and livestock productivity. PMID:27366650</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25800825','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25800825"><span>Salt as a mitigation option for decreasing nitrogen leaching losses from <span class="hlt">grazed</span> pastures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ledgard, Stewart F; Welten, Brendon; Betteridge, Keith</p> <p>2015-12-01</p> <p>The main source of nitrogen (N) leaching from <span class="hlt">grazed</span> pastures is animal urine with a high N deposition <span class="hlt">rate</span> (i.e. per urine patch), particularly between late summer and early winter. Salt is a potential mitigation option as a diuretic to induce greater drinking-water intake, increase urination frequency, decrease urine N concentration and urine N deposition <span class="hlt">rate</span>, and thereby potentially decrease N leaching. This hypothesis was tested in three phases: a cattle metabolism stall study to examine effects of salt supplementation <span class="hlt">rate</span> on water consumption, urination frequency and urine N concentration; a <span class="hlt">grazing</span> trial to assess effects of salt (150 g per heifer per day) on urination frequency; and a lysimeter study on effects of urine N <span class="hlt">rate</span> on N leaching. Salt supplementation increased cattle water intake. Urination frequency increased by up to 69%, with a similar decrease in urine N deposition <span class="hlt">rate</span> and no change in individual urination volume. Under field <span class="hlt">grazing</span>, sensors showed increased urination frequency by 17%. Lysimeter studies showed a proportionally greater decrease in N leaching with decreased urine N <span class="hlt">rate</span>. Modelling revealed that this could decrease per-hectare N leaching by 10-22%. Salt supplementation increases cattle water intake and urination frequency, resulting in a lower urine N deposition <span class="hlt">rate</span> and proportionally greater decrease in urine N leaching. Strategic salt supplementation in autumn/early winter with feed is a practical mitigation option to decrease N leaching in <span class="hlt">grazed</span> pastures. © 2015 Society of Chemical Industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27641768','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27641768"><span><span class="hlt">Zooplankton</span> Gut Passage Mobilizes Lithogenic Iron for Ocean Productivity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schmidt, Katrin; Schlosser, Christian; Atkinson, Angus; Fielding, Sophie; Venables, Hugh J; Waluda, Claire M; Achterberg, Eric P</p> <p>2016-10-10</p> <p>Iron is an essential nutrient for phytoplankton, but low concentrations limit primary production and associated atmospheric carbon drawdown in large parts of the world's oceans [1, 2]. Lithogenic particles deriving from aeolian dust deposition, glacial runoff, or river discharges can form an important source if the attached iron becomes dissolved and therefore bioavailable [3-5]. Acidic digestion by <span class="hlt">zooplankton</span> is a potential mechanism for iron mobilization [6], but evidence is lacking. Here we show that Antarctic krill sampled near glacial outlets at the island of South Georgia (Southern Ocean) ingest large amounts of lithogenic particles and contain 3-fold higher iron concentrations in their muscle than specimens from offshore, which confirms mineral dissolution in their guts. About 90% of the lithogenic and biogenic iron ingested by krill is passed into their fecal pellets, which contain ∼5-fold higher proportions of labile (reactive) iron than intact diatoms. The mobilized iron can be released in dissolved form directly from krill or via multiple pathways involving microbes, other <span class="hlt">zooplankton</span>, and krill predators. This can deliver substantial amounts of bioavailable iron and contribute to the fertilization of coastal waters and the ocean beyond. In line with our findings, phytoplankton blooms downstream of South Georgia are more intensive and longer lasting during years with high krill abundance on-shelf. Thus, krill crop phytoplankton but boost new production via their nutrient supply. Understanding and quantifying iron mobilization by <span class="hlt">zooplankton</span> is essential to predict ocean productivity in a warming climate where lithogenic iron inputs from deserts, glaciers, and rivers are increasing [7-10]. Copyright © 2016 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26270936','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26270936"><span>Seasonal foraging patterns of forest-<span class="hlt">grazing</span> Japanese Black heifers with increased plasma total antioxidant capacity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Haga, Satoshi; Nakano, Miwa; Nakao, Seiji; Hirano, Kiyoshi; Yamamoto, Yoshito; Sasaki, Hiroyuki; Ishizaki, Hiroshi</p> <p>2016-02-01</p> <p>Forest-<span class="hlt">grazing</span> enables the intake of high total antioxidant capacity (TAC) plants that might be beneficial for the TAC status of cattle. This study evaluated the relation between the seasonal foraging patterns of forest-<span class="hlt">grazing</span> Japanese Black (JB) heifers or the TAC levels in shrubs and trees and the changes of plasma TAC. We examined 12 JB heifers, four each of which were allocated to forest-<span class="hlt">grazing</span> (F), pasture-<span class="hlt">grazing</span>, and pen-housed groups. The plasma TAC level in F heifers on July 26, August 13, 30 and September 17 were significantly higher than those on April 27 and June 4 (P < 0.05). In F group, the mean <span class="hlt">rates</span> of foraging frequency (FF) of shrubs and trees during July 5-8 and September 13-16 were much higher than that during May 31-June 3 (P < 0.05). The <span class="hlt">rate</span> of FF of grass significantly decreased later in the season (P < 0.05). The mean TAC levels in these shrubs and trees were higher than those in grasses, concentrates, and timothy hay. Results suggest that an important factor in the increase of plasma TAC in forest-<span class="hlt">grazing</span> cattle might be the increased foraging of TAC-rich shrubs and trees during summer-fall. © 2015 Japanese Society of Animal Science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME44A0832N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME44A0832N"><span>PCR-Based Assessment of Freshwater <span class="hlt">Zooplankton</span> Feeding on Edible and "Inedible" Prey In Situ.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nejstgaard, J. C.; Belyaeva, M.; Van den Wyngaert, S.; Berger, S. A.; Grossart, H. P.; Kasprzak, P.</p> <p>2016-02-01</p> <p>Microbiota in pelagic ecosystems can affect <span class="hlt">zooplankton</span> nutrition in several ways that are not readily assessable in situ, using classical approaches. In contrast to classical food web models identifying phytoplankton as the dominant food source for crustacean <span class="hlt">zooplankton</span>, recent findings increasingly suggest that <span class="hlt">zooplankton</span> may derive a significant part of the diet from a wide variety of taxa including ciliates, aquatic fungi, bacteria and small metazoan <span class="hlt">zooplankton</span> (e.g. rotifers), in both marine and freshwaters. Direct quantification of soft-bodied and non-pigmented prey in <span class="hlt">zooplankton</span> guts as well as symbionts and parasites on the prey and <span class="hlt">zooplankton</span> itself has so far been impeded by the lack of appropriate methodology. We aim to establish molecular approaches to quantify these yet-understudied interactions in lake food webs. As a first step we have validated the qPCR detection method in laboratory experiments with cladoceran, calanoid and cyclopoid predators and algal prey species (Cryptomonas sp.). We plan to apply the method to study the dietary contribution of aquatic fungi - chytrids, which are parasites on inedible phytoplankton species, thus aiming to provide insights into the Mycoloop - energy transfer from inedible phytoplankton to <span class="hlt">zooplankton</span> via fungal parasites. The quantitative PCR method, when validated for key <span class="hlt">zooplankton</span> species and specific prey or parasite groups, has a potential for a broad range of applications in food web research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104688&Lab=NHEERL&keyword=manpower+AND+based+AND+research&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104688&Lab=NHEERL&keyword=manpower+AND+based+AND+research&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>SPATIAL PATTERNS IN ASSEMBLAGE STRUCTURES OF PELAGIC FORAGE FISH AND <span class="hlt">ZOOPLANKTON</span> IN WESTERN LAKE SUPERIOR</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>This manuscript reports on the spatial distribution of <span class="hlt">zooplankton</span> and forage fish in western Lake Superior. Fish and <span class="hlt">zooplankton</span> assemblages are shown to differ substantially in abundance and size structure both between the open lake and nearshore regions and between two differe...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=210166&keyword=Population+AND+numbers&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=210166&keyword=Population+AND+numbers&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Effect of Main-stem Dams on <span class="hlt">Zooplankton</span> Communities of the Missouri River (USA)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>We examined the distribution and abundance of <span class="hlt">zooplankton</span> from 146 sites on the Missouri River and found large shifts in the dominance of major taxa between management zones of this regulated river. Crustacean <span class="hlt">zooplankton</span> were dominant in the inter-reservoir zone of the river, an...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=80225&keyword=hplc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=80225&keyword=hplc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>PHYTOPLANKTON AND <span class="hlt">ZOOPLANKTON</span> SEASONAL DYNAMICS IN A SUBTROPICAL ESTUARY: IMPORTANCE OF CYANOBACTERIA</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Murrell, Michael C. and Emile M. Lores. 2004. Phytoplankton and <span class="hlt">Zooplankton</span> Seasonal Dynamics in a Subtropical Estuary: Importance of Cyanobacteria. J. Plankton Res. 26(3):371-382. (ERL,GB 1190). <br><br>A seasonal study of phytoplankton and <span class="hlt">zooplankton</span> was conducted from 1999-20...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JMS...177...28J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JMS...177...28J"><span>Temporal and spatial variability of <span class="hlt">zooplankton</span> on the Faroe shelf in spring 1997-2016</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jacobsen, Sólvá; Gaard, Eilif; Larsen, Karin Margretha Húsgarð; Eliasen, Sólvá Káradóttir; Hátún, Hjálmar</p> <p>2018-01-01</p> <p><span class="hlt">Zooplankton</span> availability during spring and summer determines the growth and survival of first-feeding fish larvae, and thus impacts the recruitment to both fish prey species and commercial fish stocks. On the Faroe shelf, however, the relative importance of oceanic versus neritic <span class="hlt">zooplankton</span> species has hitherto not been well understood. In this study, spatio-temporal variability in <span class="hlt">zooplankton</span> community structure and size spectra on the Faroe shelf is investigated using observations from late April during the period 1997-2016. The main objective was to explore which environmental variables influence the <span class="hlt">zooplankton</span> community structure in early spring. The <span class="hlt">zooplankton</span> community in the permanently well mixed central shelf inside the tidal front consists of a mixture of neritic, cosmopolitan and oceanic species. In this region, redundancy analyses showed that chlorophyll concentration had a positive effect on abundance of neritic copepods and meroplankton as well as all <span class="hlt">zooplankton</span> < 1.2 mm. The abundance variability of these species shows increased production around 2000 and 2008-2009. The highest <span class="hlt">zooplankton</span> abundance, mainly consisting of Calanus finmarchicus, is however observed off-shore from the tidal front, especially on the western side of the Faroe Plateau. A shift in C. finmarchicus phenology occurred around 2007, resulting in earlier reproduction of this species, and this variability could not be explained by the employed regional environmental parameters. Our results indicate that the Faroe shelf biological production is more dependent on the local primary production and neritic <span class="hlt">zooplankton</span> species than on the large oceanic C. finmarchicus stock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B51H0450P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B51H0450P"><span>Effects of nitrogen deposition and cattle <span class="hlt">grazing</span> on productivity, invasion impact, and soil microbial processes in a serpentine grassland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pasari, J.; Hernandez, D.; Selmants, P. C.; Keck, D.</p> <p>2010-12-01</p> <p>In recent decades, human activities have vastly increased the amount of biologically available nitrogen (N) in the biosphere. The resulting increase in N availability has broadly affected ecosystems through increased productivity, changes in species composition, altered nutrient cycles, and increases in invasion by exotic plant species, especially in systems that were historically low in N. California serpentine grasslands are N-limited ecosystems historically dominated by native species including several threatened and endangered plants and animals. Cattle <span class="hlt">grazing</span> has emerged as the primary tool for controlling the impact of nitrophilic exotic grasses whose increased abundance has paralleled the regional traffic-derived increase in atmospheric N deposition. We examined the interactive effects of cattle <span class="hlt">grazing</span> and N deposition on plant community composition, productivity, invasion resistance, and microbial processes in the Bay Area's largest serpentine grassland to determine the efficacy of current management strategies as well as the biogeochemical consequences of exotic species invasion. In the first two years of the study, aboveground net primary productivity decreased in response to <span class="hlt">grazing</span> and increased in response to nitrogen addition. However, contrary to our hypotheses the change in productivity was not due to an increase in exotic species cover as there was little overall effect of <span class="hlt">grazing</span> or N addition on species composition. Microbial activity was more responsive to <span class="hlt">grazing</span> and N. Potential net N mineralization <span class="hlt">rates</span> increased with N addition, but were not affected by <span class="hlt">grazing</span>. In contrast, soil respiration <span class="hlt">rates</span> were inhibited by <span class="hlt">grazing</span>, but were not affected by N addition; suggesting strong carbon-limitation of soil microbial activity, particularly under <span class="hlt">grazing</span>. Site differences in soil depth and <span class="hlt">grazing</span> intensity were often more important than treatment effects. We suspect that the unusually dry conditions in the first two growing seasons inhibited</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.3791L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.3791L"><span>Modeling the <span class="hlt">grazing</span> effect on dry grassland carbon cycling with modified Biome-BGC <span class="hlt">grazing</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luo, Geping; Han, Qifei; Li, Chaofan; Yang, Liao</p> <p>2014-05-01</p> <p>Identifying the factors that determine the carbon source/sink strength of ecosystems is important for reducing uncertainty in the global carbon cycle. Arid grassland ecosystems are a widely distributed biome type in Xinjiang, Northwest China, covering approximately one-fourth the country's land surface. These grasslands are the habitat for many endemic and rare plant and animal species and are also used as pastoral land for livestock. Using the modified Biome-BGC <span class="hlt">grazing</span> model, we modeled carbon dynamics in Xinjiang for grasslands that varied in <span class="hlt">grazing</span> intensity. In general, this regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source, with a value of 0.38 Pg C over the period 1979-2007. There were significant effects of <span class="hlt">grazing</span> on carbon dynamics. An over-compensatory effect in net primary productivity (NPP) and vegetation carbon (C) stock was observed when <span class="hlt">grazing</span> intensity was lower than 0.40 head/ha. <span class="hlt">Grazing</span> resulted in a net carbon source of 23.45 g C m-2 yr-1, which equaled 0.37 Pg in Xinjiang in the last 29 years. In general, <span class="hlt">grazing</span> decreased vegetation C stock, while an increasing trend was observed with low <span class="hlt">grazing</span> intensity. The soil C increased significantly (17%) with long-term <span class="hlt">grazing</span>, while the soil C stock exhibited a steady trend without <span class="hlt">grazing</span>. These findings have implications for grassland ecosystem management as it relates to carbon sequestration and climate change mitigation, e.g., removal of <span class="hlt">grazing</span> should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales. One of the greatest limitations in quantifying the effects of herbivores on carbon cycling is identifying the <span class="hlt">grazing</span> systems and intensities within a given region. We hope our study emphasizes the need for large-scale assessments of how <span class="hlt">grazing</span> impacts carbon cycling. Most terrestrial ecosystems in Xinjiang have been affected by disturbances to a greater or lesser extent in the past</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22420261','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22420261"><span>A degree-day model of sheep <span class="hlt">grazing</span> influence on alfalfa weevil and crop characteristics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Goosey, Hayes B</p> <p>2012-02-01</p> <p>Domestic sheep (Ovis spp.) <span class="hlt">grazing</span> is emerging as an integrated pest management tactic for alfalfa weevil, Hypera postica (Gyllenhal), management and a degree-day model is needed as a decision and support tool. In response to this need, <span class="hlt">grazing</span> exclosures with unique degree-days and stocking <span class="hlt">rates</span> were established at weekly intervals in a central Montana alfalfa field during 2008 and 2009. Analyses indicate that increased stocking <span class="hlt">rates</span> and <span class="hlt">grazing</span> degree-days were associated with decreased crop levels of weevil larvae. Larval data collected from <span class="hlt">grazing</span> treatments were regressed against on-site and near-site temperatures that produced the same accuracy. The near-site model was chosen to encourage producer acceptance. The regression slope differed from zero, had an r2 of 0.83, and a root mean square error of 0.2. Crop data were collected to achieve optimal weevil management with forage quality and yield. Differences were recorded in crude protein, acid and neutral detergent fibers, total digestible nutrients, and mean stage by weight. Stem heights differed with higher stocking <span class="hlt">rates</span> and degree-days recording the shortest alfalfa canopy height at harvest. The degree-day model was validated at four sites during 2010 with a mean square prediction error of 0.74. The recommendation from this research is to stock alfalfa fields in the spring before 63 DD with <span class="hlt">rates</span> between 251 and 583 sheep days per hectare (d/ha). Sheep should be allowed to <span class="hlt">graze</span> to a minimum of 106 and maximum of 150 DD before removal. This model gives field entomologists a new method for implementing <span class="hlt">grazing</span> in an integrated pest management program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008BGD.....5..411S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008BGD.....5..411S"><span>Microzooplankton <span class="hlt">grazing</span> and phytoplankton growth in marine mesocosms with increased CO2 levels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suffrian, K.; Simonelli, P.; Nejstgaard, J. C.; Putzeys, S.; Carotenuto, Y.; Antia, A. N.</p> <p>2008-01-01</p> <p>Microzooplankton <span class="hlt">grazing</span> and algae growth responses to increasing pCO2 levels (350, 700 and 1050 μatm) were investigated in nitrate and phosphate fertilized mesocosms during the PeECE III experiment 2005. <span class="hlt">Grazing</span> and growth <span class="hlt">rates</span> were estimated by the dilution technique combined with taxon specific HPLC pigment analysis. Phytoplankton and microzooplankton composition were determined by light microscopy. Despite a range up to 3 times the present CO2 levels, there were no clear differences in any measured parameter between the different CO2 treatments. Thus, during the first 9 days of the experiment the algae community standing stock (SS), measured as chlorophyll a (Chl a), showed the highest instantaneous grow <span class="hlt">rates</span> (0.02-0.99 d-1) and increased from ca 2-3 to 6-12 μg l-1, in all mesocosms. Afterwards the phytoplankton SS decreased in all mesocosms until the end of the experiment. The microzooplankton SS, that was mainly dinoflagellates and ciliates varied between 23 and 130 μg C l-1, peaking on day 13-15, apparently responding to the phytoplankton development. Instantaneous Chl a growth <span class="hlt">rates</span> were generally higher than the <span class="hlt">grazing</span> <span class="hlt">rates</span>, indicating only a limited overall effect of microzooplankton <span class="hlt">grazing</span> on the most dominant phytoplankton. Diatoms and prymnesiophytes were significantly <span class="hlt">grazed</span> (14-43% of the SS d-1) only in the pre-bloom phase when they were in low numbers and in the post-bloom phase when they were already limited by low nutrients and/or virus lysis. The cyanobacteria populations appeared more effected by microzooplankton <span class="hlt">grazing</span>, generally removing 20-65% of the SS d-1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008BGeo....5.1145S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008BGeo....5.1145S"><span>Microzooplankton <span class="hlt">grazing</span> and phytoplankton growth in marine mesocosms with increased CO2 levels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suffrian, K.; Simonelli, P.; Nejstgaard, J. C.; Putzeys, S.; Carotenuto, Y.; Antia, A. N.</p> <p>2008-08-01</p> <p>Microzooplankton <span class="hlt">grazing</span> and algae growth responses to increasing pCO2 levels (350, 700 and 1050 μatm) were investigated in nitrate and phosphate fertilized mesocosms during the PeECE III experiment 2005. <span class="hlt">Grazing</span> and growth <span class="hlt">rates</span> were estimated by the dilution technique combined with taxon specific HPLC pigment analysis. Microzooplankton composition was determined by light microscopy. Despite a range of up to 3 times the present CO2 levels, there were no clear differences in any measured parameter between the different CO2 treatments. During days 3 9 of the experiment the algae community standing stock, measured as chlorophyll a (Chl-a), showed the highest instantaneous grow <span class="hlt">rates</span> (k=0.37 0.99 d-1) and increased from ca. 2 3 to 6 12 μg l-1, in all mesocosms. Afterwards the phytoplankton standing stock decreased in all mesocosms until the end of the experiment. The microzooplankton standing stock, that was mainly constituted by dinoflagellates and ciliates, varied between 23 and 130 μg C l-1 (corresponding to 1.9 and 10.8 μmol C l-1), peaking on day 13 15, apparently responding to the phytoplankton development. Instantaneous Chl-a growth <span class="hlt">rates</span> were generally higher than the <span class="hlt">grazing</span> <span class="hlt">rates</span>, indicating only a limited overall effect of microzooplankton <span class="hlt">grazing</span> on the most dominant phytoplankton. Diatoms and prymnesiophytes were significantly <span class="hlt">grazed</span> (12 43% of the standing stock d-1) only in the pre-bloom phase when they were in low numbers, and in the post-bloom phase when they were already affected by low nutrients and/or viral lysis. The cyanobacteria populations appeared more affected by microzooplankton <span class="hlt">grazing</span> which generally removed 20 65% of the standing stock per day.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26066861','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26066861"><span>Factors driving the seasonal distribution of <span class="hlt">zooplankton</span> in a eutrophicated Mediterranean Lagoon.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ziadi, Boutheina; Dhib, Amel; Turki, Souad; Aleya, Lotfi</p> <p>2015-08-15</p> <p>The distribution of the <span class="hlt">zooplankton</span> community was studied along with environmental factors at five sampling stations in Ghar El Melh Lagoon (GML) (Mediterranean Sea, northern Tunisia). GML is characterized by specific following properties: broad and shallow, freshwater supply (Station 1); connection to the sea (S2); stagnation (S3 especially), and eutrophic conditions with enhanced nutrient concentrations (S4 and S5). Samples were taken twice monthly from February 2011 to January 2012. Twenty-three <span class="hlt">zooplankton</span> groups comprising 10 larval stages were identified. <span class="hlt">Zooplankton</span> assemblages were largely dominated by copepods (37.25%), followed respectively by ciliates (21.09%), bivalve larvae (14.88%) and gastropod veligers (12.53%). Redundancy analysis indicated that while no significant difference was found in the distribution of <span class="hlt">zooplankton</span> at any station, a strong difference was observed according to season. Both temporal and physicochemical fluctuations explain more than 50% of changes in <span class="hlt">zooplankton</span> abundances. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028009','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028009"><span><span class="hlt">Zooplankton</span> size selection relative to gill raker spacing in rainbow trout</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Budy, P.; Haddix, T.; Schneidervin, R.</p> <p>2005-01-01</p> <p>Rainbow trout Oncorhynchus mykiss are one of the most widely stocked salmonids worldwide, often based on the assumption that they will effectively utilize abundant invertebrate food resources. We evaluated the potential for feeding morphology to affect prey selection by rainbow trout using a combination of laboratory feeding experiments and field observations in Flaming Gorge Reservoir, Utah-Wyoming. For rainbow trout collected from the reservoir, inter-gill raker spacing averaged 1.09 mm and there was low variation among fish overall (SD = 0.28). Ninety-seven percent of all <span class="hlt">zooplankton</span> observed in the diets of rainbow trout collected in the reservoir were larger than the interraker spacing, while only 29% of the <span class="hlt">zooplankton</span> found in the environment were larger than the interraker spacing. Over the size range of rainbow trout evaluated here (200-475 mm), interraker spacing increased moderately with increasing fish length; however, the size of <span class="hlt">zooplankton</span> found in the diet did not increase with increasing fish length. In laboratory experiments, rainbow trout consumed the largest <span class="hlt">zooplankton</span> available; the mean size of <span class="hlt">zooplankton</span> observed in the diets was significantly larger than the mean size of <span class="hlt">zooplankton</span> available. Electivity indices for both laboratory and field observations indicated strong selection for larger-sized <span class="hlt">zooplankton</span>. The size threshold at which electivity switched from selection against smaller-sized <span class="hlt">zooplankton</span> to selection for larger-sized <span class="hlt">zooplankton</span> closely corresponded to the mean interraker spacing for both groups (???1-1.2 mm). The combination of results observed here indicates that rainbow trout morphology limits the retention of different-sized <span class="hlt">zooplankton</span> prey and reinforces the importance of understanding how effectively rainbow trout can utilize the type and sizes of different prey available in a given system. These considerations may improve our ability to predict the potential for growth and survival of rainbow trout within and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70029590','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70029590"><span>Reduced growth and survival of larval razorback sucker fed selenium-laden <span class="hlt">zooplankton</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hamilton, Steven J.; Buhl, Kevin J.; Bullard, Fern A.; McDonald, Susan</p> <p>2005-01-01</p> <p>Four groups of larval razorback sucker, an endangered fish, were exposed to selenium-laden <span class="hlt">zooplankton</span> and survival, growth, and whole-body residues were measured. Studies were conducted with 5, 10, 24, and 28-day-old larvae fed <span class="hlt">zooplankton</span> collected from six sites adjacent to the Green River, Utah. Water where <span class="hlt">zooplankton</span> were collected had selenium concentrations ranging from <0.4 to 78 μg/L, and concentrations in <span class="hlt">zooplankton</span> ranged from 2.3 to 91 μg/g dry weight. Static renewal tests were conducted for 20 to 25 days using reference water with selenium concentrations of <1.1 μg/L. In all studies, 80–100% mortality occurred in 15–20 days. In the 28-day-old larvae, fish weight was significantly reduced 25% in larvae fed <span class="hlt">zooplankton</span> containing 12 μg/g selenium. Whole-body concentrations of selenium ranged from 3.7 to 14.3 μg/g in fish fed <span class="hlt">zooplankton</span> from the reference site (Sheppard Bottom pond 1) up to 94 μg/g in fish fed <span class="hlt">zooplankton</span> from North Roadside Pond. Limited information prior to the studies suggested that the Sheppard pond 1 site was relatively clean and suitable as a reference treatment; however, the nearly complete mortality of larvae and elevated concentrations of selenium in larvae and selenium and other elements in <span class="hlt">zooplankton</span> indicated that this site was contaminated with selenium and other elements. Selenium concentrations in whole-body larvae and in <span class="hlt">zooplankton</span> from all sites were close to or greater than toxic thresholds where adverse effects occur in fish. Delayed mortality occurred in larvae fed the two highest selenium concentrations in <span class="hlt">zooplankton</span> and was thought due to an interaction with other elements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24119808','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24119808"><span>Dairy cows increase ingestive mastication and reduce ruminative chewing when <span class="hlt">grazing</span> chicory and plantain.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gregorini, P; Minnee, E M K; Griffiths, W; Lee, J M</p> <p>2013-01-01</p> <p>, and increased ingestive mastications 5 and 3 times for chicory and plantain, respectively. Cows allocated to chicory and plantain reduced bite <span class="hlt">rate</span> and bites per <span class="hlt">grazing</span> step linearly, and increased the number of mastications per bite of pasture dry matter intake while <span class="hlt">grazing</span> pasture after having <span class="hlt">grazed</span> chicory and plantain. These results indicate that cows <span class="hlt">grazing</span> chicory and plantain masticate more during ingestion and reduce rumination time and chewing. They also suggest that chicory presents greater constraints to ingestion than does plantain. Thus, although chicory has been considered to have a greater nutritive value than plantain, its overall feeding value may be no greater than that of plantain. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15526788','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15526788"><span>Effects of previous <span class="hlt">grazing</span> nutrition and management on feedlot performance of cattle.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Drouillard, J S; Kuhl, G L</p> <p>1999-01-01</p> <p>Management strategies designed to improve <span class="hlt">grazing</span> animal performance can influence feedlot performance and carcass traits both positively and negatively. In spite of the economic relevance of potential interactions between <span class="hlt">grazing</span> and finishing performance, controlled experiments evaluating integrated production systems are limited in number. Effects of <span class="hlt">grazing</span> treatments can result from, or be overshadowed by, changes in gut fill, thus making it difficult to assign precise costs to different phases of production. Published reports have considered the effects of stocking <span class="hlt">rate</span>, duration of <span class="hlt">grazing</span>, forage characteristics, supplementation, and growth-promoting implants on subsequent finishing performance. Improvements in cattle performance attributed to changes in stocking <span class="hlt">rate</span> generally have been neutral to positive with respect to effects on finishing performance. Comparisons among forages have led to the suggestion that forage species may contribute to differences in gastrointestinal fill of <span class="hlt">grazing</span> cattle, thereby influencing gain and efficiency during the subsequent finishing phase. Creep-feeding suckling calves generally has increased preweaning performance but has had relatively little influence on performance during the subsequent finishing phase. Grain supplementation of stocker cattle during the <span class="hlt">grazing</span> period has improved <span class="hlt">grazing</span> performance, but effects on subsequent feedlot performance have been inconsistent. Potential carryover effects from protein and mineral supplementation also have been inconclusive. Lack of congruence among studies is puzzling but may be the consequence of highly varied production systems, differences in experimental procedures, and changes in gut fill or mass of internal organs. Based on the studies reviewed, the expression or absence of compensatory growth during the finishing phase appears to be related to the nutritional quality of forages utilized in the <span class="hlt">grazing</span> period, with higher quality forages tending to yield greater</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol1/pdf/CFR-2010-title25-vol1-sec166-305.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol1/pdf/CFR-2010-title25-vol1-sec166-305.pdf"><span>25 CFR 166.305 - When is <span class="hlt">grazing</span> capacity determined?</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... 25 Indians 1 2010-04-01 2010-04-01 false When is <span class="hlt">grazing</span> capacity determined? 166.305 Section 166.305 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER <span class="hlt">GRAZING</span> PERMITS Land and Operations Management § 166.305 When is <span class="hlt">grazing</span> capacity determined? Before we grant, modify, or...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=347692','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=347692"><span>The economic cost of noxious weeds on Montana <span class="hlt">grazing</span> lands</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>We distributed a 16-question survey concerning noxious weed abundances, impacts and management to livestock producers <span class="hlt">grazing</span> on privately-owned or leased <span class="hlt">grazing</span> lands in Montana. The noxious weeds most commonly reported as being present on respondents’ <span class="hlt">grazing</span> units were Canada thistle (64% of gra...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=250456','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=250456"><span>How Does “Hunger” Level Impact <span class="hlt">Grazing</span> Behavior?</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p><span class="hlt">Grazing</span> behavior can be influenced through feeding and <span class="hlt">grazing</span> management decisions. Research at our USDA-ARS lab showed that ruminal fill, or how ‘hungry’ the cow is, can affect <span class="hlt">grazing</span> behavior. Cows that had less ruminal fill took a bigger bite that was shallow and wide, compared to a ‘full’ cow ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/24605','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/24605"><span>Managing <span class="hlt">grazing</span> of riparian areas in the Intermountain Region</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Warren P. Clary; Bert F. Webster</p> <p>1989-01-01</p> <p>Concern about livestock <span class="hlt">grazing</span> in riparian habitats and its effect upon riparian-dependent resources has resulted in numerous controversies about the appropriate management approach. This document provides guidance for <span class="hlt">grazing</span> of riparian areas in a manner that should reduce both nonpoint source pollution and potential <span class="hlt">grazing</span> impacts on other riparian-dependent...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/39642','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/39642"><span>Estimating influence of stocking regimes on livestock <span class="hlt">grazing</span> distributions</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Matthew J. Rinella; Marty Vavra; Bridgett J. Naylor; Jennifer M. Boyd</p> <p>2011-01-01</p> <p>Livestock often concentrate <span class="hlt">grazing</span> in particular regions of landscapes while partly or wholly avoiding other regions. Dispersing livestock from the heavily <span class="hlt">grazed</span> regions is a central challenge in <span class="hlt">grazing</span> land management. Position data gathered from GPS-collared livestock hold potential for increasing knowledge of factors driving livestock aggregation patterns, but...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/4667','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/4667"><span>Home on the range: might the cattle peacefully <span class="hlt">graze</span>?</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Sally Duncan</p> <p>1999-01-01</p> <p><span class="hlt">Grazing</span> and how it impacts the landscape is a concern for public and private land managers. This issue of "Science Findings" examines the issue of cattle and <span class="hlt">grazing</span> and provides some background, perspective, and research results on various <span class="hlt">grazing</span> systems. Researchers Jim McIver, of the Forest Service's Blue Mountains Natural Resources Institute, and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC13D1223D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC13D1223D"><span>Can Managed <span class="hlt">Grazing</span> be Part of Healthy Agroecosystems? Impacts of Various Systems on Soil Water and other Ecosystem Services</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DeLonge, M. S.; Basche, A.; Gonzalez, J.</p> <p>2016-12-01</p> <p>Due to the vast extent of <span class="hlt">grazing</span> lands, value of grassland ecosystems, and environmental impacts of the agricultural sector, it is becoming increasingly important to understand to what extent managed <span class="hlt">grazing</span> can be part of healthy agroecosystems. For example, <span class="hlt">grazing</span> systems can degrade soils, pollute water, and result in substantial direct and indirect animal emissions. On the other hand, well-managed grasslands can store more carbon, support more biodiversity, and require fewer inputs than croplands or other land uses. Systems analyses are needed to evaluate how much <span class="hlt">grazing</span> management (e.g., altering stocking <span class="hlt">rate</span> intensity or regime, integrating versus separating crops and livestock, adopting silvopasture techniques) can affect agroecosystem properties and farm viability. As a result of climate change and likely increases to rainfall variability, the effects of <span class="hlt">grazing</span> systems on soil water properties are particularly important. The primary goal of this study is to use meta-analytic techniques to better understand how changes to <span class="hlt">grazing</span> systems affect soil water properties, focusing on soil water infiltration <span class="hlt">rates</span>. Another goal is to conduct a literature survey to assess how similar changes to <span class="hlt">grazing</span> have influenced other ecosystem services (e.g., soil carbon, farm profitability) and to identify gaps in knowledge. To date, our meta-analysis includes over 100 paired comparisons (>30 studies) related to <span class="hlt">grazing</span>. The analysis is a subset of a broader study of agroecological practices that to date includes >350 paired observations. Preliminary results point to significant variability, but suggest that integrating livestock into croplands decreases infiltration (12%), whereas other changings to <span class="hlt">grazing</span> (decreasing stocking <span class="hlt">rates</span>, moving from continuous to rotational <span class="hlt">grazing</span>, or converting to a silvopasture system) can improve infiltration (by an average of 223% including all practices). Findings also suggest that removing livestock tends to increase infiltration</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24966312','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24966312"><span>Synchronous dynamics of <span class="hlt">zooplankton</span> competitors prevail in temperate lake ecosystems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vasseur, David A; Fox, Jeremy W; Gonzalez, Andrew; Adrian, Rita; Beisner, Beatrix E; Helmus, Matthew R; Johnson, Catherine; Kratina, Pavel; Kremer, Colin; de Mazancourt, Claire; Miller, Elizabeth; Nelson, William A; Paterson, Michael; Rusak, James A; Shurin, Jonathan B; Steiner, Christopher F</p> <p>2014-08-07</p> <p>Although competing species are expected to exhibit compensatory dynamics (negative temporal covariation), empirical work has demonstrated that competitive communities often exhibit synchronous dynamics (positive temporal covariation). This has led to the suggestion that environmental forcing dominates species dynamics; however, synchronous and compensatory dynamics may appear at different length scales and/or at different times, making it challenging to identify their relative importance. We compiled 58 long-term datasets of <span class="hlt">zooplankton</span> abundance in north-temperate and sub-tropical lakes and used wavelet analysis to quantify general patterns in the times and scales at which synchronous/compensatory dynamics dominated <span class="hlt">zooplankton</span> communities in different regions and across the entire dataset. Synchronous dynamics were far more prevalent at all scales and times and were ubiquitous at the annual scale. Although we found compensatory dynamics in approximately 14% of all combinations of time period/scale/lake, there were no consistent scales or time periods during which compensatory dynamics were apparent across different regions. Our results suggest that the processes driving compensatory dynamics may be local in their extent, while those generating synchronous dynamics operate at much larger scales. This highlights an important gap in our understanding of the interaction between environmental and biotic forces that structure communities. © 2014 The Author(s) Published by the Royal Society. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22325448','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22325448"><span>Neustonic microplastic and <span class="hlt">zooplankton</span> in the North Western Mediterranean Sea.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Collignon, Amandine; Hecq, Jean-Henri; Glagani, François; Voisin, Pierre; Collard, France; Goffart, Anne</p> <p>2012-04-01</p> <p>Neustonic microplastic and <span class="hlt">zooplankton</span> abundance was determined in the North Western Mediterranean Sea during a summer cruise between July 9th and August 6th 2010, with a break between July 22 th and 25th due to a strong wind event. Ninety percent of the 40 stations contained microplastic particles (size 0.3-5mm) of various compositions: e.g., filaments, polystyrene, thin plastic films. An average concentration of 0.116 particles/m(2) was observed. The highest abundances (>0.36 particles/m(2)) were observed in shelf stations. The neustonic plastic particles concentrations were 5 times higher before than after the strong wind event which increased the mixing and the vertical repartition of plastic particles in the upper layers of the water column. The values rise in the same order of magnitude than in the North Pacific Gyre. The average ratio between microplastics and mesozooplankton weights was 0.5 for the whole survey and might induce a potential confusion for <span class="hlt">zooplankton</span> feeders. Copyright © 2012 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23632089','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23632089"><span>Potential acidification impacts on <span class="hlt">zooplankton</span> in CCS leakage scenarios.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Halsband, Claudia; Kurihara, Haruko</p> <p>2013-08-30</p> <p>Carbon capture and storage (CCS) technologies involve localized acidification of significant volumes of seawater, inhabited mainly by planktonic species. Knowledge on potential impacts of these techniques on the survival and physiology of <span class="hlt">zooplankton</span>, and subsequent consequences for ecosystem health in targeted areas, is scarce. The recent literature has a focus on anthropogenic greenhouse gas emissions into the atmosphere, leading to enhanced absorption of CO2 by the oceans and a lowered seawater pH, termed ocean acidification. These studies explore the effects of changes in seawater chemistry, as predicted by climate models for the end of this century, on marine biota. Early studies have used unrealistically severe CO2/pH values in this context, but are relevant for CCS leakage scenarios. Little studied meso- and bathypelagic species of the deep sea may be especially vulnerable, as well as vertically migrating <span class="hlt">zooplankton</span>, which require significant residence times at great depths as part of their life cycle. Copyright © 2013 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980HM.....33..225S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980HM.....33..225S"><span>Effects of the ``Amoco Cadiz'' oil spill on <span class="hlt">zooplankton</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samain, J. F.; Moal, J.; Coum, A.; Le Coz, J. R.; Daniel, J. Y.</p> <p>1980-03-01</p> <p>A survey of <span class="hlt">zooplankton</span> physiology on the northern coast of Brittany (France) was carried out over a one-year period by comparing two estuarine areas, one oil-polluted area (Aber Benoit) following the oil spill by the tanker “Amoco Cadiz” and one non-oil-polluted area (Rade de Brest). A new approach to an ecological survey was made by describing trophic relationships using analysis of digestive enzyme equipment (amylase and trypsin) of <span class="hlt">zooplankton</span> organisms, mesoplankton populations and some selected species. These measurements allowed determination of (a) groups of populations with homogeneous trophic and faunistic characteristics and (b) groups of species with homogeneous trophic characteristics. The study of the appearance of these groups over a one-year period revealed the succession of populations and their adaptation to the environment on the basis of biochemical analysis. These phenomena observed in the compared areas showed marked differences in the most polluted areas during the productive spring period. Specific treatment of the data using unusual correlations between digestive enzymes is discussed in terms of the immediate effect on the whole population and on a copepod ( Anomalocera patersoni) living in the upper 10 cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1000408','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1000408"><span>Effects of alewife predation on <span class="hlt">zooplankton</span> populations in Lake Michigan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wells, LaRue</p> <p>1970-01-01</p> <p>The <span class="hlt">zooplankton</span> populations in southeastern Lake Michigan underwent striking, size-related changes between 1954 and 1966. Forms that decline sharply were the largest cladocerans (Leptodora kindtii, Daphnia galeata, and D. retrocurva), the largest calanoid copepods (Limnocalanus macrurus, Epischura lacustris, and Diaptomus sicilis), and the largest cyclopoid copepod (Mesocyclops edax). Two of these, D. galeata and M. edax (both abundant in 1954), became extremely rare. Certain medium-sized or small species increased in numbers: Daphnia longiremis, Holopedium gibberum, Polyphemus pediculus, Bosmina longirostris, Bosmina coregoni, Ceriodaphnia sp., Cyclops bicuspidatus, Cyclops vernalis, and Diaptomus ashlandi. Evidence is strong that the changes were due to selective predation by alewives. The alewife was uncommon in southeastern Lake Michigan in 1954 but had increased to enormous proportions by 1966; there was a massive dieoff in spring 1967, and abundance remained relatively low in 1968. The composition of <span class="hlt">zooplankton</span> populations in 1968 generally had shifted back toward that of 1954, although D. galeata and M. edax remained rare. The average size, and size at onset of maturity, of D. retrocurva decreased noticeably between 1954 and 1966 but increased between 1966 and 1968.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title36-vol2/pdf/CFR-2012-title36-vol2-sec292-48.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title36-vol2/pdf/CFR-2012-title36-vol2-sec292-48.pdf"><span>36 CFR 292.48 - <span class="hlt">Grazing</span> activities.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-07-01</p> <p>... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false <span class="hlt">Grazing</span> activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for which...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title36-vol2/pdf/CFR-2013-title36-vol2-sec292-48.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title36-vol2/pdf/CFR-2013-title36-vol2-sec292-48.pdf"><span>36 CFR 292.48 - <span class="hlt">Grazing</span> activities.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false <span class="hlt">Grazing</span> activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for which...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title36-vol2/pdf/CFR-2014-title36-vol2-sec292-48.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title36-vol2/pdf/CFR-2014-title36-vol2-sec292-48.pdf"><span>36 CFR 292.48 - <span class="hlt">Grazing</span> activities.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false <span class="hlt">Grazing</span> activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for which...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=323397','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=323397"><span>Chapter 2: Livestock and <span class="hlt">Grazed</span> Lands Emissions</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>A total of 342 MMT CO2 eq. of greenhouse gasses (GHGs) were emitted from livestock, managed livestock waste, and <span class="hlt">grazed</span> land in 2013. This represents about 66% of total emissions from the agricultural sector, which totaled 516 MMT CO2 eq. Compared to the base line year (1990), emissions from livesto...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol2/pdf/CFR-2010-title25-vol2-sec700-711.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol2/pdf/CFR-2010-title25-vol2-sec700-711.pdf"><span>25 CFR 700.711 - <span class="hlt">Grazing</span> permits.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands... residency on the New Lands Range Unit of permit issue, and (4) Own livestock which <span class="hlt">graze</span> on the range unit of permit issue. (c) Permits will be issued for a base of 80 SUYL (20 AU) and may not be divided or...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.4983F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.4983F"><span>Greenhouse gas exchange over <span class="hlt">grazed</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Felber, R.; Ammann, C.; Neftel, A.</p> <p>2012-04-01</p> <p>Grasslands act as sinks and sources of greenhouse gases (GHG) and are, in conjunction with livestock production systems, responsible for a large share of GHG emissions. Whereas ecosystem scale flux measurements (eddy covariance) are commonly used to investigate CO2 exchange (and is becoming state-of-the-art for other GHGs, too), GHG emissions from agricultural animals are usually investigated on the scale of individual animals. Therefore eddy covariance technique has to be tested for combined systems (i.e. <span class="hlt">grazed</span> systems). Our project investigates the ability of field scale flux measurements to reliably quantify the contribution of <span class="hlt">grazing</span> dairy cows to the net exchange of CO2 and CH4. To quantify the contribution of the animals to the net flux the position, movement, and <span class="hlt">grazing</span>/rumination activity of each cow are recorded. In combination with a detailed footprint analysis of the eddy covariance fluxes, the animal related CO2 and CH4 emissions are derived and compared to standard emission values derived from respiration chambers. The aim of the project is to test the assumption whether field scale CO2 flux measurements adequately include the respiration of <span class="hlt">grazing</span> cows and to identify potential errors in ecosystem Greenhouse gas budgets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title25-vol2/pdf/CFR-2013-title25-vol2-sec700-722.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title25-vol2/pdf/CFR-2013-title25-vol2-sec700-722.pdf"><span>25 CFR 700.722 - <span class="hlt">Grazing</span> associations.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-04-01</p> <p>... association's constitution and bylaws. (3) The officers other than secretary and treasurer must be <span class="hlt">grazing</span> permittees on the range unit involved. (4) The association's activities must be governed by a constitution and bylaws acceptable to the Commissioner and signed by him. (5) The association's constitution and...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec9239-3.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec9239-3.pdf"><span>43 CFR 9239.3 - <span class="hlt">Grazing</span>, Alaska.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>..., DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.3 <span class="hlt">Grazing</span>, Alaska. (a... other authorization from the Bureau of Land Management, is prohibited and constitutes trespass... in the notice will be deemed to have been willful. (3) Where the owner of the trespassing livestock...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec9239-3.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec9239-3.pdf"><span>43 CFR 9239.3 - <span class="hlt">Grazing</span>, Alaska.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>..., DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.3 <span class="hlt">Grazing</span>, Alaska. (a... other authorization from the Bureau of Land Management, is prohibited and constitutes trespass... in the notice will be deemed to have been willful. (3) Where the owner of the trespassing livestock...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec9239-3.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec9239-3.pdf"><span>43 CFR 9239.3 - <span class="hlt">Grazing</span>, Alaska.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>..., DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.3 <span class="hlt">Grazing</span>, Alaska. (a... other authorization from the Bureau of Land Management, is prohibited and constitutes trespass... in the notice will be deemed to have been willful. (3) Where the owner of the trespassing livestock...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title43-vol2/pdf/CFR-2014-title43-vol2-sec9239-3.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title43-vol2/pdf/CFR-2014-title43-vol2-sec9239-3.pdf"><span>43 CFR 9239.3 - <span class="hlt">Grazing</span>, Alaska.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>..., DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.3 <span class="hlt">Grazing</span>, Alaska. (a... other authorization from the Bureau of Land Management, is prohibited and constitutes trespass... in the notice will be deemed to have been willful. (3) Where the owner of the trespassing livestock...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/20899','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/20899"><span>Restoring Native California Oaks on <span class="hlt">Grazed</span> Rangelands</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Douglas D. McCreary; Jerry Tecklin</p> <p>2005-01-01</p> <p>Efforts to regenerate oaks on California’s oak woodlands often must address how to establish seedlings in areas <span class="hlt">grazed</span> by livestock. Research indicates that damage to young oak seedlings from cattle varies by season, with less damage during the winter when deciduous oaks do not have leaves. While exclusion of cattle from planted areas does result in reduced damage, the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/33931','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/33931"><span>Public land <span class="hlt">grazing</span> for private land conservation?</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Adriana Sulak; Lynn Huntsinger; Sheila Barry; Larry Forero</p> <p>2008-01-01</p> <p>California ranchers with substantial private oak woodlands sometimes use public lands as an important component of their production cycle. Yet allowed public <span class="hlt">grazing</span> has declined and is likely to continue to decline. This, combined with intensifying development pressure and land use change, dramatically affects the resource base for ranch operations, which in turn...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=remote+AND+viewing&pg=3&id=EJ501180','ERIC'); return false;" href="https://eric.ed.gov/?q=remote+AND+viewing&pg=3&id=EJ501180"><span>Delineating <span class="hlt">Grazing</span>: Observations of Remote Control Use.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Eastman, Susan Tyler; Newton, Gregory D.</p> <p>1995-01-01</p> <p>States that contrary to previous reports of "<span class="hlt">grazing</span>," most viewers only used their remote control devices (RCDs) once or twice every half hour. Claims that the dominant RCD operation was direct channel punching, as opposed to dial turning. Concludes that most RCD activity did not take place during a program, thus voiding industry…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=remote+AND+viewing&pg=3&id=ED311523','ERIC'); return false;" href="https://eric.ed.gov/?q=remote+AND+viewing&pg=3&id=ED311523"><span>The Gratifications of <span class="hlt">Grazing</span>: Why Flippers Flip.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Walker, James R.; Bellamy, Robert V., Jr.</p> <p></p> <p>An exploratory study focused on usage patterns of television remote control devices (RCDs), examining how and why individuals use television RCDs to "<span class="hlt">graze</span>." The study identified the gratifications obtained from RCD use and evaluated their relative importance in accounting for variations in RCD use. Subjects were 455 undergraduates in…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/518387-solar-uvb-induced-dna-damage-photoenzymatic-dna-repair-antarctic-zooplankton','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/518387-solar-uvb-induced-dna-damage-photoenzymatic-dna-repair-antarctic-zooplankton"><span>Solar UVB-induced DNA damage and photoenzymatic DNA repair in antarctic <span class="hlt">zooplankton</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Malloy, K.D.; Holman, M.A.; Mitchell, D.</p> <p></p> <p>The detrimental effects of elevated intensities of mid-UV radiation (UVB), a result of stratospheric ozone depletion during the austral spring, on the primary producers of the Antarctic marine ecosystem have been well documented. Here we report that natural populations of Antarctic <span class="hlt">zooplankton</span> also sustain significant DNA damage [measured as cyclobutane pyrimidine dimers (CPDs)] during periods of increased UVB flux. This is the first direct evidence that increased solar UVB may result in damage to marine organisms other than primary producers in Antarctica. The extent of DNA damage in pelagic icefish eggs correlated with daily incident UVB irradiance, reflecting the differencemore » between acquisition and repair of CPDs. Patterns of DNA damage in fish larvae did not correlated with daily UVB flux, possibly due to different depth distributions and/or different capacities for DNA repair. Clearance of CPDs by Antarctic fish and krill was mediated primarily by the photoenzymatic repair system. Although repair <span class="hlt">rates</span> were large for all species evaluated, they were apparently inadequate to prevent the transient accumulation of substantial CPD burdens. The capacity for DNA repair in Antarctic organisms was highest in those species whose early life history stages occupy the water column during periods of ozone depletion (austral spring) and lowest in fish species whose eggs and larvae are abundant during winter. Although the potential reduction in fitness of Antarctic <span class="hlt">zooplankton</span> resulting from DNA damage is unknown, we suggest that increased solar UV may reduce recruitment and adversely affect trophic transfer of productivity by affecting heterotrophic species as well as primary producers. 54 refs., 4 figs., 2 tabs.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMGC31A0693Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMGC31A0693Y"><span>Simulating the effects of soil organic nitrogen and <span class="hlt">grazing</span> on arctic tundra vegetation dynamics on the Yamal Peninsula, Russia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Q.; Epstein, H. E.; Walker, D. A.</p> <p>2009-12-01</p> <p>Sustainability of tundra vegetation under changing climate on the Yamal Peninsula, northwestern Siberia, home to the world’s largest area of reindeer husbandry, is of crucial importance to the local native community. An integrated investigation is needed for better understanding of the effects of soils, climate change and <span class="hlt">grazing</span> on tundra vegetation in the Yamal region. In this study we applied a nutrient-based plant community model (ArcVeg) to evaluate how two factors (soil organic nitrogen [SON] levels and <span class="hlt">grazing</span>) interact to affect tundra responses to climate warming across a latitudinal climatic gradient on the Yamal Peninsula. Model simulations were driven by field-collected soil data and expected <span class="hlt">grazing</span> patterns along the Yamal Arctic Transect (YAT), within bioclimate subzones C (High Arctic), D (northern Low Arctic) and E (southern Low Arctic). Plant biomass and NPP (net primary productivity) were significantly increased with warmer bioclimate subzones, greater soil nutrient levels and temporal climate warming, while they declined with higher <span class="hlt">grazing</span> frequency. Temporal climate warming of 2 °C caused an increase of 665 g/m2 in total biomass at the high SON site in subzone E, while only 298 g/m2 in the low SON site. When <span class="hlt">grazing</span> frequency was also increased, total biomass increased by only 369 g/m2 in the high SON site in contrast to 184 g/m2 in the low SON site in subzone E. When comparing low <span class="hlt">grazing</span> to high <span class="hlt">grazing</span> effects on soil organic nitrogen pools over time (Figure 1), higher <span class="hlt">grazing</span> frequency led to either slower SON accumulation <span class="hlt">rates</span> or more rapid SON depletion <span class="hlt">rates</span>. Warming accentuated these differences caused by <span class="hlt">grazing</span>, suggesting the interaction between <span class="hlt">grazing</span> and warming may yield greater differences in SON levels across sites. Our results suggest that low SON and <span class="hlt">grazing</span> may limit plant response to climate change. Interactions among bioclimate subzones, soils, <span class="hlt">grazing</span> and warming significantly affect plant biomass and productivity in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10463397','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10463397"><span>Influence of <span class="hlt">grazing</span> management on the seasonal change in testicular morphology in Corriedale rams.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bielli, A; Pedrana, G; Gastel, M T; Castrillejo, A; Moraña, A; Lundeheim, N; Forsberg, M; Rodriguez-Martinez, H</p> <p>1999-06-28</p> <p>The present study was conducted: (a) to determine the degree of seasonal variation in testis stereology in Corriedale rams between autumn and winter; (b) to test the hypothesis that testis stereology of Corriedale rams <span class="hlt">grazing</span> native pastures during autumn and winter would differ from those of Corriedale rams <span class="hlt">grazing</span> sown pastures and supplemented with grain during the same period; and (c) to determine whether Sertoli cell numbers differ in adult rams between the breeding season (autumn) and the following non-breeding season (winter). Twenty experimental animals were studied. Six rams (autumn control group, C-A) that had been <span class="hlt">grazing</span> on native pasture (stocking <span class="hlt">rate</span> = 2-3 animals ha(-1)) were castrated at the beginning of the experiment (March, early autumn). Seven rams (winter control group, C-W) continued to <span class="hlt">graze</span> on native pasture at the same stocking <span class="hlt">rate</span> until the end of the experiment (August, late winter). Another seven rams (treated group, T) <span class="hlt">grazed</span> on improved pasture (stocking <span class="hlt">rate</span> = 1-2 animals ha(-1)) and were supplemented with 1 kg grain ram(-1) day(-1) until the end of the experiment. Live weight, scrotal circumference, serum testosterone concentration and selected testicular stereological parameters were measured. The treatment did not impede the winter reduction in testicular activity and reduced its magnitude slightly (group T) compared with controls (group C-W). Sertoli cell numbers were higher in autumn (group C-A) than in winter, both on native (group C-W) and sown pastures (group T). Diminishing Sertoli cell numbers between autumn and the following winter suggest the occurrence of that Sertoli cell death during this period. The results indicate that, although the reproductive activity of Corriedale rams is moderately seasonal, a restricted change in <span class="hlt">grazing</span> and grain supplementation can only modify it to a limited extent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JMS....93....4O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JMS....93....4O"><span>Estimation of mortality for stage-structured <span class="hlt">zooplankton</span> populations: What is to be done?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohman, Mark D.</p> <p>2012-05-01</p> <p>Estimation of <span class="hlt">zooplankton</span> mortality <span class="hlt">rates</span> in field populations is a challenging task that some contend is inherently intractable. This paper examines several of the objections that are commonly raised to efforts to estimate mortality. We find that there are circumstances in the field where it is possible to sequentially sample the same population and to resolve biologically caused mortality, albeit with error. Precision can be improved with sampling directed by knowledge of the physical structure of the water column, combined with adequate sample replication. Intercalibration of sampling methods can make it possible to sample across the life history in a quantitative manner. <span class="hlt">Rates</span> of development can be constrained by laboratory-based estimates of stage durations from temperature- and food-dependent functions, mesocosm studies of molting <span class="hlt">rates</span>, or approximation of development <span class="hlt">rates</span> from growth <span class="hlt">rates</span>, combined with the vertical distributions of organisms in relation to food and temperature gradients. Careful design of field studies guided by the assumptions of specific estimation models can lead to satisfactory mortality estimates, but model uncertainty also needs to be quantified. We highlight additional issues requiring attention to further advance the field, including the need for linked cooperative studies of the <span class="hlt">rates</span> and causes of mortality of co-occurring holozooplankton and ichthyoplankton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27363345','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27363345"><span><span class="hlt">Grazing</span> effects on ecosystem CO2 fluxes differ among temperate steppe types in Eurasia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hou, Longyu; Liu, Yan; Du, Jiancai; Wang, Mingya; Wang, Hui; Mao, Peisheng</p> <p>2016-07-01</p> <p>Grassland ecosystems play a critical role in regulating CO2 fluxes into and out of the Earth's surface. Whereas previous studies have often addressed single fluxes of CO2 separately, few have addressed the relation among and controls of multiple CO2 sub-fluxes simultaneously. In this study, we examined the relation among and controls of individual CO2 fluxes (i.e., GEP, NEP, SR, ER, CR) in three contrasting temperate steppes of north China, as affected by livestock <span class="hlt">grazing</span>. Our findings show that climatic controls of the seasonal patterns in CO2 fluxes were both individual flux- and steppe type-specific, with significant <span class="hlt">grazing</span> impacts observed for canopy respiration only. In contrast, climatic controls of the annual patterns were only individual flux-specific, with minor <span class="hlt">grazing</span> impacts on the individual fluxes. <span class="hlt">Grazing</span> significantly reduced the mean annual soil respiration <span class="hlt">rate</span> in the typical and desert steppes, but significantly enhanced both soil and canopy respiration in the meadow steppe. Our study suggests that a reassessment of the role of livestock <span class="hlt">grazing</span> in regulating GHG exchanges is imperative in future studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25828258','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25828258"><span><span class="hlt">Grazing</span> livestock are exposed to terrestrial cyanobacteria.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McGorum, Bruce C; Pirie, R Scott; Glendinning, Laura; McLachlan, Gerry; Metcalf, James S; Banack, Sandra A; Cox, Paul A; Codd, Geoffrey A</p> <p>2015-02-25</p> <p>While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of <span class="hlt">grazing</span> livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 <span class="hlt">grazing</span> horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of <span class="hlt">grazing</span> horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in <span class="hlt">grazing</span> horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in <span class="hlt">grazing</span> livestock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004IJBm...48..213V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004IJBm...48..213V"><span>Evaporative cooling for Holstein dairy cows under <span class="hlt">grazing</span> conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valtorta, Silvia E.; Gallardo, Miriam R.</p> <p></p> <p>. Twenty-four <span class="hlt">grazing</span> Holstein cows in mid and late lactation were randomly assigned to two treatment groups: control and cooled. The trial was performed at the Experimental Dairy Unit, Rafaela Agricultural Experimental Station (INTA), Argentina. The objective was to evaluate the effects of sprinkler and fan cooling before milkings on milk production and composition. The effects of the cooling system on rectal temperature and respiration <span class="hlt">rate</span> were also evaluated. Cooled cows showed higher milk production (1.04 l cow-1 day-1). The concentration and yield of milk fat and protein increased in response to cooling treatment. The cooling system also reduced rectal temperature and respiration <span class="hlt">rate</span>. No effects were observed on body condition. It was concluded that evaporative cooling, which is efficient for housed animals, is also appropriate to improve yields and animal well-being under <span class="hlt">grazing</span> systems. These results are impressive since the cooling system was utilized only before milkings, in a system where environmental control is very difficult to achieve. This trial was performed during a mild summer. The results would probably be magnified during hotter weather.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017IJBC...2750088H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017IJBC...2750088H"><span>Cross-Diffusion Induced Turing Instability and Amplitude Equation for a Toxic-Phytoplankton-<span class="hlt">Zooplankton</span> Model with Nonmonotonic Functional Response</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, Renji; Dai, Binxiang</p> <p>2017-06-01</p> <p>The spatiotemporal pattern induced by cross-diffusion of a toxic-phytoplankton-<span class="hlt">zooplankton</span> model with nonmonotonic functional response is investigated in this paper. The linear stability analysis shows that cross-diffusion is the key mechanism for the formation of spatial patterns. By taking cross-diffusion <span class="hlt">rate</span> as bifurcation parameter, we derive amplitude equations near the Turing bifurcation point for the excited modes in the framework of a weakly nonlinear theory, and the stability analysis of the amplitude equations interprets the structural transitions and stability of various forms of Turing patterns. Furthermore, we illustrate the theoretical results via numerical simulations. It is shown that the spatiotemporal distribution of the plankton is homogeneous in the absence of cross-diffusion. However, when the cross-diffusivity is greater than the critical value, the spatiotemporal distribution of all the plankton species becomes inhomogeneous in spaces and results in different kinds of patterns: spot, stripe, and the mixture of spot and stripe patterns depending on the cross-diffusivity. Simultaneously, the impact of toxin-producing <span class="hlt">rate</span> of toxic-phytoplankton (TPP) species and natural death <span class="hlt">rate</span> of <span class="hlt">zooplankton</span> species on pattern selection is also explored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104900&keyword=principle+AND+management&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104900&keyword=principle+AND+management&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>EVALUATION OF OPTICALLY ACQUIRED <span class="hlt">ZOOPLANKTON</span> SIZE-SPECTRUM DATA AS A POTENTIAL TOOL FOR ASSESSMENT OF CONDITION IN THE GREAT LAKES</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>An optical <span class="hlt">zooplankton</span> counter (OPC) potentially provides as assessment tool for <span class="hlt">zooplankton</span> condition in ecosystems that is rapid, economical, and spatially extensive. We collected <span class="hlt">zooplankton</span> data with an optical <span class="hlt">zooplankton</span> counter in 20 near-shore regions of four of the Laure...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24496839','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24496839"><span>The effect of bermudagrass hybrid on forage characteristics, animal performance, and <span class="hlt">grazing</span> behavior of beef steers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Scaglia, G; Boland, H T</p> <p>2014-03-01</p> <p>Bermudagrass (Cynodon dactylon [L.] Pers.) is a major feed source for ruminants across the southeastern United States. In 4 consecutive yr, 3 different bermudagrass hybrids, Alicia, Jiggs, and Tifton-85, were evaluated under a low stocking <span class="hlt">rate</span> as forage and hay sources. The nutritive value, in situ DM digestibility, and performance and <span class="hlt">grazing</span> behavior of beef steers under similar management were evaluated. Sampling day had an effect (P < 0.05) on all forage variables. Percentages of CP and TDN decreased while concentration of ADF, NDF, lignin, and nonfiber carbohydrates (NFC) increased as <span class="hlt">grazing</span> season advanced. Alicia had lower nutritive value, showing greater lignin (5.3%) and indigestible fraction (44.9%) compared to Jiggs (4.9 and 35.6%, respectively) and Tifton-85 (4.5 and 40.1%, respectively). Tifton-85 contained the lowest concentration of NFC (11.8%). Steers <span class="hlt">grazing</span> Jiggs and Tifton-85 had greater ADG (0.51 and 0.55 kg, respectively) and BW gain per hectare (258 and 279 kg, respectively) than those on Alicia (0.36 kg and 184 kg/ha, respectively); results that are probably explained by the lower nutritive value characteristics of the latter. Most <span class="hlt">grazing</span> behavior variables were affected (P < 0.05) by time of the day (TOD) and <span class="hlt">grazing</span> period. Two major <span class="hlt">grazing</span> events were observed at dawn and dusk. <span class="hlt">Grazing</span> time (32 min) was lowest (P = 0.003) while standing (140 min) and lying (98 min) time were greater (P = 0.001 and 0.04, respectively) from 1100 to 1559 h, probably as an effect of temperature and humidity at that time of the day. During summer, the temperature humidity index (THI) is above 72 (mild heat load) for the entire season and above 79 (severe heat load) during most of the daylight hours from June to August. Heat load likely affected animal performance and <span class="hlt">grazing</span> behavior; however, some characteristics associated with these bermudagrass hybrids, especially with Alicia, such as its percentages of lignin and indigestible fraction may also</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BGD....1218315H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BGD....1218315H"><span>Dead zone or oasis in the open ocean? <span class="hlt">Zooplankton</span> distribution and migration in low-oxygen modewater eddies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hauss, H.; Christiansen, S.; Schütte, F.; Kiko, R.; Edvam Lima, M.; Rodrigues, E.; Karstensen, J.; Löscher, C. R.; Körtzinger, A.; Fiedler, B.</p> <p>2015-11-01</p> <p> OMZ day and night (e.g. ostracods, polychaetes), and iv) DVM through the shallow OMZ from deeper oxygenated depths to the surface and back. For strategy (i), (ii) and (iv), compression of the habitable volume in the surface may increase prey-predator encounter <span class="hlt">rates</span>, rendering <span class="hlt">zooplankton</span> more vulnerable to predation and potentially making the eddy surface a foraging hotspot for higher trophic levels. With respect to long-term effects of ocean deoxygenation, we expect <span class="hlt">zooplankton</span> avoidance of the mesopelagic OMZ to set in if oxygen levels decline below approximately 20 μmol O2 kg-1. This may result in a positive feedback on the OMZ oxygen consumption <span class="hlt">rates</span>, since <span class="hlt">zooplankton</span> respiration within the OMZ as well as active flux of dissolved and particulate organic matter into the OMZ will decline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=244078','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=244078"><span><span class="hlt">Grazing</span> effect on woody plant recruitment in a Sonoran Desert grassland across space and time</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Livestock <span class="hlt">grazing</span> is a commonly cited factor contributing to shrub encroachment in savannas and grasslands. Patterns of woody plant proliferation are known to influence <span class="hlt">rates</span> of erosion and spread of disturbance and are of practical importance to livestock management with regard to forage distribut...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ECSS...71..657S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ECSS...71..657S"><span><span class="hlt">Zooplankton</span> responses to sandbar opening in a tropical eutrophic coastal lagoon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santangelo, Jayme M.; de M. Rocha, Adriana; Bozelli, Reinaldo L.; Carneiro, Luciana S.; de A. Esteves, Francisco</p> <p>2007-02-01</p> <p>The effects of a disturbance by sandbar opening on the <span class="hlt">zooplankton</span> community were evaluated through a long-term study in an eutrophic and oligohaline system, Imboassica Lagoon, Rio de Janeiro, Brazil. <span class="hlt">Zooplankton</span> samples and limnological data were collected monthly from March 2000 to February 2003. Before the sandbar was opened in February 2001, the lagoon showed eutrophic conditions, with high mean nutrient concentrations and low salinity (total nitrogen - TN = 190.28 μM, chlorophyll a content - Chl. a = 104.60 μg/L and salinity = 0.87'). During this period, the <span class="hlt">zooplankton</span> species present, such as the rotifers Brachionus calyciflorus and Brachionus havanaensis, were typical of freshwater to oligohaline and eutrophic environments. After the sandbar opening, the lagoon changed to a lower trophic status and increased salinity (TN = 55.11 μM, Chl. a = 27.56 μg/L and salinity = 19.64'). As a result, the <span class="hlt">zooplankton</span> community came to consist largely of the rotifer Brachionus plicatilis, marine copepods and meroplanktonic larvae, mainly Gastropoda. Salinity was the main force structuring the <span class="hlt">zooplankton</span> community after the sandbar opening. Two years after this episode, the prior <span class="hlt">zooplankton</span> community had not reestablished itself, indicating a low resilience to this disturbance. The conditions developed prior to a sandbar opening can be crucial to the community responses in the face of this disturbance and for the capacity of the original <span class="hlt">zooplankton</span> community to re-establish itself.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ChJOL..32..858C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ChJOL..32..858C"><span><span class="hlt">Zooplankton</span> community analysis in the Changjiang River estuary by single-gene-targeted metagenomics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, Fangping; Wang, Minxiao; Li, Chaolun; Sun, Song</p> <p>2014-07-01</p> <p>DNA barcoding provides accurate identification of <span class="hlt">zooplankton</span> species through all life stages. Single-gene-targeted metagenomic analysis based on DNA barcode databases can facilitate longterm monitoring of <span class="hlt">zooplankton</span> communities. With the help of the available <span class="hlt">zooplankton</span> databases, the <span class="hlt">zooplankton</span> community of the Changjiang (Yangtze) River estuary was studied using a single-gene-targeted metagenomic method to estimate the species richness of this community. A total of 856 mitochondrial cytochrome oxidase subunit 1 (cox1) gene sequences were determined. The environmental barcodes were clustered into 70 molecular operational taxonomic units (MOTUs). Forty-two MOTUs matched barcoded marine organisms with more than 90% similarity and were assigned to either the species (similarity>96%) or genus level (similarity<96%). Sibling species could also be distinguished. Many species that were overlooked by morphological methods were identified by molecular methods, especially gelatinous <span class="hlt">zooplankton</span> and merozooplankton that were likely sampled at different life history phases. <span class="hlt">Zooplankton</span> community structures differed significantly among all of the samples. The MOTU spatial distributions were influenced by the ecological habits of the corresponding species. In conclusion, single-gene-targeted metagenomic analysis is a useful tool for <span class="hlt">zooplankton</span> studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSED23A..05C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSED23A..05C"><span>Under the Scope: Bringing <span class="hlt">Zooplankton</span> Research into the K-12 Classroom</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohen, J.; Petrone, C.; Wickline, A.</p> <p>2016-02-01</p> <p>Despite their small size, <span class="hlt">zooplankton</span> are dynamic and engaging animals when viewed by researchers, teachers, and students alike. Recognizing this, we are working with K-12 teachers to develop web-based resources for using <span class="hlt">zooplankton</span> in the classroom. This outreach effort is part of a Delaware Sea Grant-funded research project studying seasonal dynamics of <span class="hlt">zooplankton</span> in Delaware Bay. The research team, in collaboration with a marine education specialist, initially created a website (www.underthescope.udel.edu) containing: background information on <span class="hlt">zooplankton</span> and the research project, a magnification tool, an identification tool, and education modules that facilitate directed use of the website content and tools. Local teachers (elementary through high school) were then hosted for a workshop to engage in <span class="hlt">zooplankton</span> sampling using methods employed in the research project, including <span class="hlt">zooplankton</span> tows and semi-autonomous identification using a ZooScan imaging system. Teachers then explored the website, evaluating its design, content, and usability for their particular grade level. Specific suggestions from the evaluation were incorporated into the website, with additional implementation planned over the next year. This teacher- researcher partnership was successful in developing the digital resource itself, in building excitement and capacity among a cohort of teachers, and in establishing relationships among teachers and researchers to facilitate adding new dimensions to the collaboration. The latter will include <span class="hlt">zooplankton</span> sampling by school groups, researcher optical scanning of samples with ZooScan, and subsequent student analysis and reporting on their data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ChJOL..35.1144Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ChJOL..35.1144Y"><span>Community composition, abundance and biomass of <span class="hlt">zooplankton</span> in Zhangzi Island waters, Northern Yellow Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yin, Jiehui; Zhang, Guangtao; Li, Chaolun; Wang, Shiwei; Zhao, Zengxia; Wan, Aiyong</p> <p>2017-09-01</p> <p>Samples were collected monthly from the sea area around Zhangzi Island, northern Yellow Sea, from July 2009 to June 2010. Vertical net towing was used to examine spatial and temporal variability in <span class="hlt">zooplankton</span> abundance and biomass. Overall, Calanus sinicus and Saggita crassa were the dominant species found during the study period, while the amphipod Themisto gracilipes was dominant in winter and spring. Vast numbers of the ctenophore species of the genus Beroe were found in October and November. It was not possible to count them, but they constituted a large portion of the total <span class="hlt">zooplankton</span> biomass. <span class="hlt">Zooplankton</span> species diversity was highest in October, and species evenness was highest in April. <span class="hlt">Zooplankton</span> abundance (non-jellyfish) and biomass were highest in June and lowest in August, with annual averages of 131.3 ind./m³ and 217.5 mg/m³, respectively. Water temperature may be responsible for the variations in <span class="hlt">zooplankton</span> abundance and biomass. Beroe biomass was negatively correlated with other <span class="hlt">zooplankton</span> abundance. Longterm investigations will be carried out to learn more about the influence of the environment on <span class="hlt">zooplankton</span> assemblages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29306392','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29306392"><span>Effects of increased <span class="hlt">zooplankton</span> biomass on phytoplankton and cyanotoxins: A tropical mesocosm study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dos Santos Severiano, Juliana; Dos Santos Almeida-Melo, Viviane Lúcia; Bittencourt-Oliveira, Maria do Carmo; Chia, Mathias Ahii; do Nascimento Moura, Ariadne</p> <p>2018-01-01</p> <p><span class="hlt">Zooplankton</span> are important biocontrol agents for algal blooms in temperate lakes, while their potential in tropical and subtropical environments is not well understood. The aim of the present study was to evaluate the influence of increased <span class="hlt">zooplankton</span> biomass on phytoplankton community and cyanotoxins (microcystins and saxitoxin) content of a tropical reservoir (Ipojuca reservoir, Brazil) using in situ mesocosms. Mesocosms consisted of 50L transparent polyethylene bags suspended in the reservoir for twelve days. Phytoplankton populations were exposed to treatments having 1 (control), 2, 3 and 4 times the biomass of <span class="hlt">zooplankton</span> found in the reservoir at the beginning of the experiment. Filamentous cyanobacteria such as Planktothrix agardhii and Cylindrospermopsis raciborskii were not negatively influenced by increasing <span class="hlt">zooplankton</span> biomass. In contrast, the treatments with 3 and 4 times <span class="hlt">zooplankton</span> biomass negatively affected the cyanobacteria Aphanocapsa sp., Chroococcus sp., Dolichospermum sp., Merismopedia tenuissima, Microcystis aeruginosa and Pseudanabaena sp.; the diatom Cyclotella meneghiniana; and the cryptophyte Cryptomonas sp. Total microcystin concentration both increased and decreased at different times depending on <span class="hlt">zooplankton</span> treatment, while saxitoxin level was not significantly different between the treatments and control. The results of the present study suggest that <span class="hlt">zooplankton</span> biomass can be manipulated to control the excessive proliferation of non-filamentous bloom forming cyanobacteria (e.g. M. aeruginosa) and their associated cyanotoxins. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5209667','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5209667"><span>Temporal variation of cesium isotope concentrations and atom ratios in <span class="hlt">zooplankton</span> in the Pacific off the east coast of Japan</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ikenoue, Takahito; Takata, Hyoe; Kusakabe, Masashi; Kudo, Natsumi; Hasegawa, Kazuyuki; Ishimaru, Takashi</p> <p>2017-01-01</p> <p>After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, concentrations of cesium isotopes (133Cs, 134Cs, and 137Cs) were measured in <span class="hlt">zooplankton</span> collected in the Pacific off the east coast of Japan from May 2012 to February 2015. The time series of the data exhibited sporadic 137Cs concentration peaks in <span class="hlt">zooplankton</span>. In addition, the atom ratio of 137Cs/133Cs in <span class="hlt">zooplankton</span> was consistently high compared to that in ambient seawater throughout the sampling period. These phenomena cannot be explained fully by the bioaccumulation of 137Cs in <span class="hlt">zooplankton</span> via ambient seawater intake, the inclusion of resuspended sediment in the plankton sample, or the taxonomic composition of the plankton. Autoradiography revealed highly radioactive particles within <span class="hlt">zooplankton</span> samples, which could be the main factor underlying the sporadic appearance of high 137Cs concentrations in <span class="hlt">zooplankton</span> as well as the higher ratio of 137Cs/133Cs in <span class="hlt">zooplankton</span> than in seawater. PMID:28051136</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28051136','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28051136"><span>Temporal variation of cesium isotope concentrations and atom ratios in <span class="hlt">zooplankton</span> in the Pacific off the east coast of Japan.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ikenoue, Takahito; Takata, Hyoe; Kusakabe, Masashi; Kudo, Natsumi; Hasegawa, Kazuyuki; Ishimaru, Takashi</p> <p>2017-01-04</p> <p>After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, concentrations of cesium isotopes ( 133 Cs, 134 Cs, and 137 Cs) were measured in <span class="hlt">zooplankton</span> collected in the Pacific off the east coast of Japan from May 2012 to February 2015. The time series of the data exhibited sporadic 137 Cs concentration peaks in <span class="hlt">zooplankton</span>. In addition, the atom ratio of 137 Cs/ 133 Cs in <span class="hlt">zooplankton</span> was consistently high compared to that in ambient seawater throughout the sampling period. These phenomena cannot be explained fully by the bioaccumulation of 137 Cs in <span class="hlt">zooplankton</span> via ambient seawater intake, the inclusion of resuspended sediment in the plankton sample, or the taxonomic composition of the plankton. Autoradiography revealed highly radioactive particles within <span class="hlt">zooplankton</span> samples, which could be the main factor underlying the sporadic appearance of high 137 Cs concentrations in <span class="hlt">zooplankton</span> as well as the higher ratio of 137 Cs/ 133 Cs in <span class="hlt">zooplankton</span> than in seawater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1008368','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1008368"><span>Response of mountain meadows to <span class="hlt">grazing</span> by recreational pack stock</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cole, David N.; Van Wagtendonk, Jan W.; McClaran, Mitchel P.; Moore, Peggy E.; McDougald, Neil K.</p> <p>2004-01-01</p> <p>Effects of recreational pack stock <span class="hlt">grazing</span> on mountain meadows in Yosemite National Park were assessed in a 5-year study. Yosemite is a designated wilderness, to be managed such that its natural conditions are preserved. Studies were conducted in 3 characteristic meadow types: shorthair sedge (Carex filifolia Nutt.), Brewer's reed grass (Calamagrostis breweri Thurber), and tufted hairgrass [Deschampsia cespitosa (L.) Beauv.]. Horses and mules <span class="hlt">grazed</span> experimental plots at intensities of 15 to 69% utilization for 4 seasons. In all 3 meadows, <span class="hlt">grazing</span> caused decreases in productivity. The mean reduction after 4 years of <span class="hlt">grazing</span> was 18% in the shorthair sedge meadow, 17% in the Brewer's reed grass meadow, and 22% in the tufted hairgrass meadow. <span class="hlt">Grazing</span> also caused shifts in basal groundcover (usually a reduction in vegetation cover and increase in bare soil cover), and changes in species composition. Productivity and vegetation cover decreased as percent utilization increased, while bare soil cover increased as utilization increased. Changes in species composition were less predictably related to differences in <span class="hlt">grazing</span> intensity. Passive management of <span class="hlt">grazing</span> is insufficient in wilderness areas that are regularly used by groups with recreational stock. Wilderness managers need to monitor meadow conditions and the <span class="hlt">grazing</span> intensities that occur. Our study suggests that biomass and ground cover are more sensitive indicators of <span class="hlt">grazing</span> impact than species composition. Managers must make decisions about maximum acceptable levels of <span class="hlt">grazing</span> impact and then develop guidelines for maximum use levels, based on data such as ours that relates <span class="hlt">grazing</span> intensity to meadow response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GBioC..31.1089F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GBioC..31.1089F"><span>Quantification of uncertainties in global <span class="hlt">grazing</span> systems assessment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fetzel, T.; Havlik, P.; Herrero, M.; Kaplan, J. O.; Kastner, T.; Kroisleitner, C.; Rolinski, S.; Searchinger, T.; Van Bodegom, P. M.; Wirsenius, S.; Erb, K.-H.</p> <p>2017-07-01</p> <p>Livestock systems play a key role in global sustainability challenges like food security and climate change, yet many unknowns and large uncertainties prevail. We present a systematic, spatially explicit assessment of uncertainties related to <span class="hlt">grazing</span> intensity (GI), a key metric for assessing ecological impacts of <span class="hlt">grazing</span>, by combining existing data sets on (a) <span class="hlt">grazing</span> feed intake, (b) the spatial distribution of livestock, (c) the extent of <span class="hlt">grazing</span> land, and (d) its net primary productivity (NPP). An analysis of the resulting 96 maps implies that on average 15% of the <span class="hlt">grazing</span> land NPP is consumed by livestock. GI is low in most of the world's <span class="hlt">grazing</span> lands, but hotspots of very high GI prevail in 1% of the total <span class="hlt">grazing</span> area. The agreement between GI maps is good on one fifth of the world's <span class="hlt">grazing</span> area, while on the remainder, it is low to very low. Largest uncertainties are found in global drylands and where <span class="hlt">grazing</span> land bears trees (e.g., the Amazon basin or the Taiga belt). In some regions like India or Western Europe, massive uncertainties even result in GI > 100% estimates. Our sensitivity analysis indicates that the input data for NPP, animal distribution, and <span class="hlt">grazing</span> area contribute about equally to the total variability in GI maps, while <span class="hlt">grazing</span> feed intake is a less critical variable. We argue that a general improvement in quality of the available global level data sets is a precondition for improving the understanding of the role of livestock systems in the context of global environmental change or food security.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMGC51A0714B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMGC51A0714B"><span>Stable carbon isotopes of <span class="hlt">zooplankton</span> lipid components as a tool to differentiate between pelagic and ice algae as a food source for <span class="hlt">zooplankton</span> in the Arctic Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bendle, J. A.; Moossen, H.; Jamieson, R.; Wold, A.; Falk-Peterson, S.</p> <p>2009-12-01</p> <p>Every summer in the Arctic, the ice cover melts and releases sea-ice algae into the surrounding waters. How important are these algae, consisting mostly of diatoms, as a major food source for <span class="hlt">zooplankton</span> and higher trophic levels? The answer to this question is timely, given predictions for the loss of summer sea ice cover this century. We are investigating the use of compound specific carbon isotopes as a tool to differentiate between lipids found in <span class="hlt">zooplankton</span> which feed on diatoms living in the open ocean and <span class="hlt">zooplankton</span> which feed on diatoms derived from the ice. To this effect we analyse the carbon isotopic signature of the major fatty acids and alcohols and that of the major sterols collected during the Arctic ICE CHASER expedition aboard the RRV James Clark Ross in 2008. Twenty three <span class="hlt">zooplankton</span> samples comprised of 11 different species were collected in four different depth intervals at three different sites around Svalbard. The sites had variable ice cover, from open water to solid ice. We analysed the lipid composition of the <span class="hlt">zooplankton</span> samples with special emphasis on the fatty acids and fatty alcohols bound as esters. Esters are produced by <span class="hlt">zooplankton</span> to function as an energy reservoir. Initial results such as the occurrence of Brassicasterol, 24 methylencholest 5 en-3β-ol and Desmosterol, high amounts of the C20:5ω3 fatty acid and high C16:1ω7/C16:0-fatty acid ratios suggest that diatoms are an important part of the <span class="hlt">zooplankton</span> diet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3805558','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3805558"><span>Stable Isotope and Signature Fatty Acid Analyses Suggest Reef Manta Rays Feed on Demersal <span class="hlt">Zooplankton</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Couturier, Lydie I. E.; Rohner, Christoph A.; Richardson, Anthony J.; Marshall, Andrea D.; Jaine, Fabrice R. A.; Bennett, Michael B.; Townsend, Kathy A.; Weeks, Scarla J.; Nichols, Peter D.</p> <p>2013-01-01</p> <p>Assessing the trophic role and interaction of an animal is key to understanding its general ecology and dynamics. Conventional techniques used to elucidate diet, such as stomach content analysis, are not suitable for large threatened marine species. Non-lethal sampling combined with biochemical methods provides a practical alternative for investigating the feeding ecology of these species. Stable isotope and signature fatty acid analyses of muscle tissue were used for the first time to examine assimilated diet of the reef manta ray Manta alfredi, and were compared with different <span class="hlt">zooplankton</span> functional groups (i.e. near-surface <span class="hlt">zooplankton</span> collected during manta ray feeding events and non-feeding periods, epipelagic <span class="hlt">zooplankton</span>, demersal <span class="hlt">zooplankton</span> and several different <span class="hlt">zooplankton</span> taxa). Stable isotope δ15N values confirmed that the reef manta ray is a secondary consumer. This species had relatively high levels of docosahexaenoic acid (DHA) indicating a flagellate-based food source in the diet, which likely reflects feeding on DHA-rich near-surface and epipelagic <span class="hlt">zooplankton</span>. However, high levels of ω6 polyunsaturated fatty acids and slightly enriched δ13C values in reef manta ray tissue suggest that they do not feed solely on pelagic <span class="hlt">zooplankton</span>, but rather obtain part of their diet from another origin. The closest match was with demersal <span class="hlt">zooplankton</span>, suggesting it is an important component of the reef manta ray diet. The ability to feed on demersal <span class="hlt">zooplankton</span> is likely linked to the horizontal and vertical movement patterns of this giant planktivore. These new insights into the habitat use and feeding ecology of the reef manta ray will assist in the effective evaluation of its conservation needs. PMID:24167562</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/98660-high-intensity-short-duration-rotational-grazing-reclaimed-cool-season-fescue-legume-pastures-system-development','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/98660-high-intensity-short-duration-rotational-grazing-reclaimed-cool-season-fescue-legume-pastures-system-development"><span>High intensity, short duration rotational <span class="hlt">grazing</span> on reclaimed cool season fescue/legume pastures: I. System development</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Erickson, W.R.; Carlson, K.E.</p> <p></p> <p>The Pittsburg & Midway Coal Mining Co.`s ({open_quotes}P&M{close_quotes}) Midway Mine lies 50 miles south of Kansas City, Kansas, straddling the border of Kansas and Missouri. P&M actively mined the area until 1989, when the mine was closed and reclaimed. Approximately 3,750 acres of surface mined land were topsoiled and revegetated to cool season fescue/legume pasture. Various pasture management methods are being utilized to meet reclamation success standards and achieve final bond release. The effectiveness and costs of various cool season fescue/legume pasture management methods are evaluated and contrasted. These methods include sharecropping, bush hogging, burning and livestock <span class="hlt">grazing</span>. It presentsmore » guidelines used to develop a site specific rotational livestock <span class="hlt">grazing</span> programs with land owners or contractors, and local, state and federal agencies. Rotational <span class="hlt">grazing</span> uses both cow/calf or feeder livestock operations. Key managerial elements used to control <span class="hlt">grazing</span> activities, either by the landowner or a contractor, are reviewed. Methods used to determine stocking levels for successful rotational <span class="hlt">grazing</span> on this type of pasture are presented. Rotational <span class="hlt">grazing</span> of livestock has proven to be the most effective method for managing established cool season fescue/legume pastures at this site. Initial stocking <span class="hlt">rates</span> of 1 A.U.M. per 5 acres have been modified to a current stocking <span class="hlt">rate</span> of 1 A.U.M. per 2.5 acres. Supporting physical and chemical data are presented and discussed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DSRI...90...36W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DSRI...90...36W"><span>Trophic ecology and vertical patterns of carbon and nitrogen stable isotopes in <span class="hlt">zooplankton</span> from oxygen minimum zone regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams, Rebecca L.; Wakeham, Stuart; McKinney, Rick; Wishner, Karen F.</p> <p>2014-08-01</p> <p>The unique physical and biogeochemical characteristics of oxygen minimum zones (OMZs) influence plankton ecology, including <span class="hlt">zooplankton</span> trophic webs. Using carbon and nitrogen stable isotopes, this study examined <span class="hlt">zooplankton</span> trophic webs in the Eastern Tropical North Pacific (ETNP) OMZ. δ13C values were used to indicate <span class="hlt">zooplankton</span> food sources, and δ15N values were used to indicate <span class="hlt">zooplankton</span> trophic position and nitrogen cycle pathways. Vertically stratified MOCNESS net tows collected <span class="hlt">zooplankton</span> from 0 to 1000 m at two stations along a north-south transect in the ETNP during 2007 and 2008, the Tehuantepec Bowl and the Costa Rica Dome. <span class="hlt">Zooplankton</span> samples were separated into four size fractions for stable isotope analyses. Particulate organic matter (POM), assumed to represent a primary food source for <span class="hlt">zooplankton</span>, was collected with McLane large volume in situ pumps. The isotopic composition and trophic ecology of the ETNP <span class="hlt">zooplankton</span> community had distinct spatial and vertical patterns influenced by OMZ structure. The most pronounced vertical isotope gradients occurred near the upper and lower OMZ oxyclines. Material with lower δ13C values was apparently produced in the upper oxycline, possibly by chemoautotrophic microbes, and was subsequently consumed by <span class="hlt">zooplankton</span>. Between-station differences in δ15N values suggested that different nitrogen cycle processes were dominant at the two locations, which influenced the isotopic characteristics of the <span class="hlt">zooplankton</span> community. A strong depth gradient in <span class="hlt">zooplankton</span> δ15N values in the lower oxycline suggested an increase in trophic cycling just below the core of the OMZ. Shallow POM (0-110 m) was likely the most important food source for mixed layer, upper oxycline, and OMZ core <span class="hlt">zooplankton</span>, while deep POM was an important food source for most lower oxycline <span class="hlt">zooplankton</span> (except for samples dominated by the seasonally migrating copepod Eucalanus inermis). There was no consistent isotopic progression among the four</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2017/5131/sir20175131.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2017/5131/sir20175131.pdf"><span>An evaluation of the <span class="hlt">zooplankton</span> community at the Sheboygan River Area of Concern and non-Area of Concern comparison sites in western Lake Michigan rivers and harbors in 2016</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Olds, Hayley T.; Scudder Eikenberry, Barbara C.; Burns, Daniel J.; Bell, Amanda H.</p> <p>2017-12-22</p> <p>The Great Lakes Areas of Concern (AOCs) are considered to be the most severely degraded areas within the Great Lakes basin, as defined in the Great Lakes Water Quality Agreement and amendments. Among the 43 designated AOCs are four Lake Michigan AOCs in the State of Wisconsin. The smallest of these AOCs is the Sheboygan River AOC, which was designated as an AOC because of sediment contamination from polychlorinated biphenyl compounds (PCBs), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and heavy metals. The Sheboygan River AOC has 9 of 14 possible Beneficial Use Impairments (BUIs), which must be addressed to improve overall water-quality, and to ultimately delist the AOC. One of the BUIs associated with this AOC is the “degradation of phytoplankton and <span class="hlt">zooplankton</span> populations,” which can be removed from the list of impairments when it has been determined that <span class="hlt">zooplankton</span> community composition and structure at the AOC do not differ significantly from communities at non-AOC comparison sites. In 2012 and 2014, the U.S. Geological Survey collected plankton (phytoplankton and <span class="hlt">zooplankton</span>) community samples at the Sheboygan River AOC and selected non-AOC sites as part of a larger Great Lakes Restoration Initiative study evaluating both the benthos and plankton communities in all four of Wisconsin’s Lake Michigan AOCs. Although neither richness nor diversity of phytoplankton or <span class="hlt">zooplankton</span> in the Sheboygan River AOC were found to differ significantly from the non-AOC sites in 2012, results from the 2014 data indicated that <span class="hlt">zooplankton</span> diversity was significantly lower, and so <span class="hlt">rated</span> as degraded, when compared to the Manitowoc and Kewaunee Rivers, two non-AOC sites of similar size, land use, and close geographic proximity.As a follow-up to the 2014 results, <span class="hlt">zooplankton</span> samples were collected at the same locations in the AOC and non-AOC sites during three sampling trips in spring, summer, and fall 2016. An analysis of similarity indicated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008DSRII..55.2330T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008DSRII..55.2330T"><span>Pelagic and sympagic contribution of organic matter to <span class="hlt">zooplankton</span> and vertical export in the Barents Sea marginal ice zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tamelander, Tobias; Reigstad, Marit; Hop, Haakon; Carroll, Michael L.; Wassmann, Paul</p> <p>2008-10-01</p> <p>The structure and function of the marine food web strongly regulate the cycling of organic matter derived from primary production by phytoplankton and ice algae in Arctic shelf seas. Improved knowledge of trophic relationships and export of organic matter from the surface layer is needed to better understand how the Arctic marine ecosystem may respond to climate-related changes in distribution of sea ice, water masses, and associated primary production regimes. Pelagic and sympagic inputs of organic matter to dominant meso- and macrozooplankton species and vertical export were investigated in the northern Barents Sea by means of stable carbon and nitrogen isotopes (δ 13C and δ 15N). Samples were collected during spring and summer (2003-2005) from a total of 13 stations with different ice conditions, abundances of ice algae, and phytoplankton bloom phases. δ 13C signatures were different in organic matter of phytoplankton (mean -24.3‰) and ice algal origin (mean -20.0‰). Stable carbon isotope compositions showed that most of the energy assimilated by <span class="hlt">zooplankton</span> originated from pelagic primary production, but at times ice algae also contributed to <span class="hlt">zooplankton</span> diets. Trophic level (TL) estimates of copepods ( Calanus glacialis and Calanus hyperboreus) and krill ( Thysanoessa inermis and Thysanoessa longicaudata), calculated based on δ 15N values, varied among stations from 1.3 to 2.7 and from 1.5 to 3.1, for respective taxa. TL in C. glacialis was significantly and inversely related to the depth-integrated phytoplankton chlorophyll a concentration. A similar trend, although weaker, also was observed for the other species. This relationship indicates that copepods <span class="hlt">graze</span> primarily on the abundant autotrophic biomass during the peak bloom phase. At stations with lower chlorophyll a concentration, the TL of Calanus spp. was 1.0 higher, indicating omnivory outside the peak bloom phase in response to changed food availability. The majority of organic matter</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018DSRI..131..121S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018DSRI..131..121S"><span>Comparative larval growth and mortality of mesopelagic fishes and their predatory impact on <span class="hlt">zooplankton</span> in the Kuroshio region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sassa, Chiyuki; Takahashi, Motomitsu</p> <p>2018-01-01</p> <p>Larvae of mesopelagic fishes usually dominate in oceanic larval fish assemblages, but detailed investigations of their ecology are limited and thus preclude full assessment of the ecosystem structure and dynamics in oceanic waters. Here, we examined the growth and mortality of six taxa of numerically dominant mesopelagic fish larvae and their predatory impact on <span class="hlt">zooplankton</span> in the Kuroshio region off southern Japan during late winter. The weight-specific growth coefficient (Gw) ranged from 0.077 (Sigmops gracilis) to 0.156 d-1 (Vinciguerria nimbaria), and the instantaneous daily mortality coefficient (M) from 0.067 (S. gracilis) to 0.143 d-1 (Myctophum asperum). The ratio Gw/M, an index of stage-specific survival of the larvae, was from 0.90 (Notoscopelus japonicus) to 1.24 (V. nimbaria), without a significant difference from a value of 1 in all species. Based on the reported relationship between Gw and ingestion <span class="hlt">rate</span> of the larval fishes, the daily ration of each species was calculated to be 32-57% of body dry weight d-1. Mean and 95% confidence interval of food requirements of the six taxa of larvae was 1.41 ± 0.55 mg C m-2 d-1. Predatory impact of the mesopelagic fish larvae on the production <span class="hlt">rate</span> of the available prey was estimated to be approximately 3.5-5.2%, implying that the larvae have a low level but consistent effect on <span class="hlt">zooplankton</span> production in the oligotrophic Kuroshio region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5667886','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5667886"><span>Predicting temporal variation in <span class="hlt">zooplankton</span> beta diversity is challenging</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Castelo Branco, Christina W.; Kozlowsky-Suzuki, Betina; Sousa-Filho, Izidro F.; Souza, Leonardo Coimbra e; Bini, Luis Mauricio</p> <p>2017-01-01</p> <p>Beta diversity, the spatial variation in species composition, has been related to different explanatory variables, including environmental heterogeneity, productivity and connectivity. Using a long-term time series of <span class="hlt">zooplankton</span> data collected over 62 months in a tropical reservoir (Ribeirão das Lajes Reservoir, Rio de Janeiro State, Brazil), we tested whether beta diversity (as measured across six sites distributed along the main axis of the reservoir) was correlated with environmental heterogeneity (spatial environmental variation in a given month), chlorophyll-a concentration (a surrogate for productivity) and water level. We did not found evidence for the role of these predictors, suggesting the need to reevaluate predictions or at least to search for better surrogates of the processes that hypothetically control beta diversity variation. However, beta diversity declined over time, which is consistent with the process of biotic homogenization, a worldwide cause of concern. PMID:29095892</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29095892','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29095892"><span>Predicting temporal variation in <span class="hlt">zooplankton</span> beta diversity is challenging.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lopes, Vanessa Guimarães; Castelo Branco, Christina W; Kozlowsky-Suzuki, Betina; Sousa-Filho, Izidro F; Souza, Leonardo Coimbra E; Bini, Luis Mauricio</p> <p>2017-01-01</p> <p>Beta diversity, the spatial variation in species composition, has been related to different explanatory variables, including environmental heterogeneity, productivity and connectivity. Using a long-term time series of <span class="hlt">zooplankton</span> data collected over 62 months in a tropical reservoir (Ribeirão das Lajes Reservoir, Rio de Janeiro State, Brazil), we tested whether beta diversity (as measured across six sites distributed along the main axis of the reservoir) was correlated with environmental heterogeneity (spatial environmental variation in a given month), chlorophyll-a concentration (a surrogate for productivity) and water level. We did not found evidence for the role of these predictors, suggesting the need to reevaluate predictions or at least to search for better surrogates of the processes that hypothetically control beta diversity variation. However, beta diversity declined over time, which is consistent with the process of biotic homogenization, a worldwide cause of concern.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18268305','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18268305"><span>Phosphorus fertilizer and <span class="hlt">grazing</span> management effects on phosphorus in runoff from dairy pastures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dougherty, Warwick J; Nicholls, Paul J; Milham, Paul J; Havilah, Euie J; Lawrie, Roy A</p> <p>2008-01-01</p> <p>Fertilizer phosphorus (P) and <span class="hlt">grazing</span>-related factors can influence runoff P concentrations from <span class="hlt">grazed</span> pastures. To investigate these effects, we monitored the concentrations of P in surface runoff from <span class="hlt">grazed</span> dairy pasture plots (50 x 25 m) treated with four fertilizer P <span class="hlt">rates</span> (0, 20, 40, and 80 kg ha(-1) yr(-1)) for 3.5 yr at Camden, New South Wales. Total P concentrations in runoff were high (0.86-11.13 mg L(-1)) even from the control plot (average 1.94 mg L(-1)). Phosphorus fertilizer significantly (P < 0.001) increased runoff P concentrations (average runoff P concentrations from the P(20), P(40), and P(80) treatments were 2.78, 3.32, and 5.57 mg L(-1), respectively). However, the magnitude of the effect of P fertilizer varied between runoff events (P < 0.01). Further analysis revealed the combined effects on runoff P concentration of P <span class="hlt">rate</span>, P <span class="hlt">rate</span> x number of applications (P < 0.001), P <span class="hlt">rate</span> x time since fertilizer (P < 0.001), dung P (P < 0.001), time since <span class="hlt">grazing</span> (P < 0.05), and pasture biomass (P < 0.001). A conceptual model of the sources of P in runoff comprising three components is proposed to explain the mobilization of P in runoff and to identify strategies to reduce runoff P concentrations. Our data suggest that the principal strategy for minimizing runoff P concentrations from <span class="hlt">grazed</span> dairy pastures should be the maintenance of soil P at or near the agronomic optimum by the use of appropriate <span class="hlt">rates</span> of P fertilizer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24521316','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24521316"><span>Effects of <span class="hlt">grazing</span> on nesting of the Oriental pratincole (Glareola maldivarum) in Bueng Boraphet Wetland, Thailand.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chaiyarat, Rattanawat; Eiam-Ampai, Kairat</p> <p>2014-02-01</p> <p>Livestock <span class="hlt">grazing</span> may negatively impact bird nesting in wetland habitats. This study evaluated the effect of <span class="hlt">grazing</span> on the nests of the Oriental pratincole (Glareola maldivarum) along the grassland of a wetland at six study sites with different densities of <span class="hlt">grazing</span> cattle and buffalo. Species richness, density, cover, and height of vegetation in the study areas were different (P < 0.05). The density of cattle and buffalo at the various sites affected vegetation composition and amount, which in turn influenced bird nest density. The estimated trampling <span class="hlt">rates</span>, number of fledglings, and number of trampled eggs were different among study sites (P < 0.05). The density of cattle and buffalo has an influence on nest failure <span class="hlt">rates</span>. The factors that influenced the mortality <span class="hlt">rates</span> of the Oriental pratincole were trampling and unhatched eggs. Only 48.5% of the nests were successful at sites where cattle and buffalo continuously <span class="hlt">grazed</span> in the grasslands at high densities. Thus, increases in the density of cattle and buffalo will reduce the number of nests of the Oriental pratincole, which may result in a reduction of the overall population in the future.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME14D0633B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME14D0633B"><span>Metabarcoding Baseline for the Sargasso Sea <span class="hlt">Zooplankton</span> Community</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blanco-Bercial, L.; Alam, S.</p> <p>2016-02-01</p> <p>Understanding the responses and evolution of any community over space and time requires a deep knowledge of the species present at each location and their interactions. Where taxonomy turns out to be challenging, as it is in the case of <span class="hlt">zooplankton</span>, supra-species grouping is a common resort in community characterization. Although this makes morphological identification manageable, there is the associated price of a limited depth of study and the risk of mixing different species' organismal responses. As global change begins to influence species distributions and physiologies, it becomes ever more important to discriminate at a species specific level. The development of DNA-based identification protocols during the last decades are rapidly driving these limitations away, increasing our understanding of the existing complexity of even very close taxa to different stressors or environmental conditions. Beyond the mere taxonomic discrimination of the analyzed community, the use of DNA sequences allows for the rapid integration of phylogenetic measurements and related indexes. In this presentation, we show our first results tackling one of the regions with the highest <span class="hlt">zooplankton</span> diversity, the Subtropical North Atlantic at the Bermuda Atlantic Time-Series Study (BATS) site. The chosen metabarcoding region was the hypervariable V9 region of the 18S rRNA gene. In this first investigation, we establish the baseline information needed for further and more comprehensive analyses on the time series: minimum coverage depth per sample, taxonomic and phylogenetic diversity of the community and effect of the Diel Vertical Migration in the epipelagic community. We also analyze the limitations of the species identification in relation to the variability of the V9 region within and between species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4927248','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4927248"><span>Neutron Reflectivity and <span class="hlt">Grazing</span> Angle Diffraction</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ankner, J. F.; Majkrzak, C. F.; Satija, S. K.</p> <p>1993-01-01</p> <p>Over the last 10 years, neutron reflectivity has emerged as a powerful technique for the investigation of surface and interfacial phenomena in many different fields. In this paper, a short review of some of the work on neutron reflectivity and <span class="hlt">grazing</span>-angle diffraction as well as a description of the current and planned neutron rcflectometers at NIST is presented. Specific examples of the characterization of magnetic, superconducting, and polymeric surfaces and interfaces are included. PMID:28053457</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27976453','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27976453"><span>Seasonality constraints to livestock <span class="hlt">grazing</span> intensity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fetzel, Tamara; Havlik, Petr; Herrero, Mario; Erb, Karl-Heinz</p> <p>2017-04-01</p> <p>Increasing food production is essential to meet the future food demand of a growing world population. In light of pressing sustainability challenges such as climate change and the importance of the global livestock system for food security as well as GHG emissions, finding ways to increasing food production sustainably and without increasing competition for food crops is essential. Yet, many unknowns relate to livestock <span class="hlt">grazing</span>, in particular <span class="hlt">grazing</span> intensity, an essential variable to assess the sustainability of livestock systems. Here, we explore ecological limits to <span class="hlt">grazing</span> intensity (GI; i.e. the fraction of net primary production consumed by <span class="hlt">grazing</span> animals) by analysing the role of seasonality in natural grasslands. We estimate seasonal limitations to GI by combining monthly net primary production data and a map of global livestock distribution with assumptions on the length of nonfavourable periods that can be bridged by livestock (e.g. by browsing dead standing biomass, storage systems or biomass conservation). This allows us to derive a seasonality-limited potential GI, which we compare with the GI prevailing in 2000. We find that GI in 2000 lies below its potential on 39% of the total global natural grasslands, which has a potential for increasing biomass extraction of up to 181 MtC/yr. In contrast, on 61% of the area GI exceeds the potential, made possible by management. Mobilizing this potential could increase milk production by 5%, meat production by 4% or contribute to free up to 2.8 Mio km² of grassland area at the global scale if the numerous socio-ecological constraints can be overcome. We discuss socio-ecological trade-offs, which may reduce the estimated potential considerably and require the establishment of sound monitoring systems and an improved understanding of livestock system's role in the Earth system. © 2017 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.1366B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.1366B"><span>The Effect of Different Type of Herbivores, <span class="hlt">Grazing</span> Types and <span class="hlt">Grazing</span> Intensities on Alpine Basiphillous Vegetation of the Romanian Carpathians</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ballová, Zuzana; Pekárik, Ladislav; Šibík, Jozef</p> <p>2017-04-01</p> <p>The major purpose of the present study was to test the hypothesis that there are significant differences in vegetation structure, plant species composition, and soil chemical properties in relation to type of <span class="hlt">grazing</span> animals, various levels of <span class="hlt">grazing</span> intensity and <span class="hlt">grazing</span> type, and if potential differences alter with ecosystem productivity (increase in more productive ecosystems). The study was conducted in three mountain ranges of the Romanian Carpathians with a predominance of alkaline substrates (the Bucegi Mts, the Little Retezat Mts and the Ceahlău Massif). Statistical analyses were performed in R statistical software environment. The effects of <span class="hlt">grazing</span> animals (cattle, horses and sheep), <span class="hlt">grazing</span> types (fence, regular, irregular) and <span class="hlt">grazing</span> intensity (low, medium, high) on the community structure were tested using ordination methods. In the case of soil properties, General Linear Mixed Model was applied. Special statistical approach eliminated the differences between the examined mountains and sites. Type of <span class="hlt">grazing</span> animal does not significantly influence species cover but it is related to specific species occurrence. According to our results, <span class="hlt">grazing</span> horses had similar effects as cattle compared to sheep. <span class="hlt">Grazing</span> in restricted areas (surrounded by fence) and regular unrestricted <span class="hlt">grazing</span> were more similar if compared to irregular <span class="hlt">grazing</span>. When comparing the intensity of <span class="hlt">grazing</span>, high and medium intensity were more similar to each other than to the low intensity <span class="hlt">grazing</span>. Cattle <span class="hlt">grazed</span> sites had significantly higher lichens cover, while the sheep patches were covered with increased overall herb layer (forbs, graminoids and low shrubs together). Medium <span class="hlt">grazing</span> intensity decreased the lichens cover, cover of overall herb layer, and total vegetation cover compared to high and low <span class="hlt">grazing</span> intensity. <span class="hlt">Grazing</span> type had important impact on the lichens cover and cover of overall herb layer. The lichens cover appeared to decrease while the cover of overall herb layer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29710415','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29710415"><span><span class="hlt">Grazing</span> disturbance increases transient but decreases persistent soil seed bank.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Miaojun; Walck, Jeffrey L; Ma, Zhen; Wang, Lipei; Du, Guozhen</p> <p>2018-04-30</p> <p>Very few studies have examined whether the impacts of <span class="hlt">grazing</span> disturbance on soil seed banks occur directly or indirectly through aboveground vegetation and soil properties. The potential role of the seed bank in alpine wetland restoration is also unknown. We used SEM (structural equation modeling) to explore the direct effect of <span class="hlt">grazing</span> disturbance on the seed bank and the indirect effect through aboveground vegetation and soil properties. We also studied the role of the seed bank on the restoration potential in wetlands with various <span class="hlt">grazing</span> intensities: low (fenced, winter <span class="hlt">grazed</span> only), medium (seasonally <span class="hlt">grazed</span>), and high (whole-year <span class="hlt">grazed</span>). For the seed bank, species richness and density per plot showed no difference among <span class="hlt">grazing</span> intensities for each depth (0-5, 5-10, 10-15 cm) and for the whole depth (0-15 cm) in spring and summer. There was no direct effect of <span class="hlt">grazing</span> disturbance on seed bank richness and density both in spring and summer, and also no indirect effect on the seed bank through its direct effect on vegetation richness and abundance. <span class="hlt">Grazing</span> disturbance indirectly increased spring seed bank density but decreased summer seed bank density through its direct effect (negative correlation) on soil moisture and total nitrogen and its indirect effect on vegetation abundance. Species composition of the vegetation changed with <span class="hlt">grazing</span> regime, but that of the seed bank did not. An increased trend of similarity between the seed bank and aboveground vegetation with increased <span class="hlt">grazing</span> disturbance was found in the shallow depth and in the whole depth only in spring. Although there was almost no change in seed bank size with <span class="hlt">grazing</span> intensities, <span class="hlt">grazing</span> disturbance increased the quantity of transient seeds but decreased persistent seeds. Persistent seeds stored in the soil could play a crucial role in vegetation regeneration and in restoration of degraded wetland ecosystems. The seed bank should be an integral part of alpine wetland restoration programs. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983DSRA...30.1199S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983DSRA...30.1199S"><span>Dissolved and fecal pellet carbon and nitrogen release by <span class="hlt">zooplankton</span> in tropical waters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Small, Lawrence F.; Fowler, Scott W.; Moore, Stanley A.; LaRosa, Jacques</p> <p>1983-12-01</p> <p>Carbon (C) and nitrogen (N) release by tropical <span class="hlt">zooplankton</span> (mostly copepods) and micronekton (euphausiids, pelagic red crabs, and salps) was investigated near VERTEX particle traps at 18°N, 108°W (in 1981) and 15°40'N, 107°30'W (in 1982). The objective was to assess the significance of fecal pellet release relative to respiratory and dissolved excretory release of C and N and relative to primary production in the same waters. For small (< 300 μm) and large (300 to 500 μm) <span class="hlt">zooplankton</span>, 38 to 49% more ammonium-nitrogen was excreted than C was respired, relative to body concentrations of N and C, respectively. However, for the same <span class="hlt">zooplankton</span>, 40 to 54% less fecal N was egested than fecal C, again relative to body C and N contents. This apparent compensation yielded a relatively constant body C:N ratio, and, because of the relatively low ratio of respiratory C to excretory N, implied a protein-based metabolism. The same compensatory relationships were found for euphausiids and red crabs, except the percentages of C and N losses were lower than for the <span class="hlt">zooplankton</span>. No such compensatory relationship was found for the salps, using respiratory—excretory data from the literature and our own observations of fecal pellet production. Either the literature data were not applicable to our salps, or the salps had a more lipid-based metabolism. Reasonably balanced C and N loss budgets were computed for the small and large <span class="hlt">zooplankton</span>. Daily fecal pellet C egestion represented only 2 to 3% of both large and small <span class="hlt">zooplankton</span> body C content, and daily fecal pellet N egestion was <2% of <span class="hlt">zooplankton</span> body N. Likewise, daily fecal pellet production by small and large <span class="hlt">zooplankton</span> together accounted for <2% of the daily primary C and N production in the top 100 m of water; that is, 'new' primary production would have had to replace losses of <2% per day to balance fecal pellet losses from large and small <span class="hlt">zooplankton</span>, presuming all fecal pellets sank below 100 m without being</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27410261','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27410261"><span>Indicator Properties of Baltic <span class="hlt">Zooplankton</span> for Classification of Environmental Status within Marine Strategy Framework Directive.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gorokhova, Elena; Lehtiniemi, Maiju; Postel, Lutz; Rubene, Gunta; Amid, Callis; Lesutiene, Jurate; Uusitalo, Laura; Strake, Solvita; Demereckiene, Natalja</p> <p>2016-01-01</p> <p>The European Marine Strategy Framework Directive requires the EU Member States to estimate the level of anthropogenic impacts on their marine systems using 11 Descriptors. Assessing food web response to altered habitats is addressed by Descriptor 4 and its indicators, which are being developed for regional seas. However, the development of simple foodweb indicators able to assess the health of ecologically diverse, spatially variable and complex interactions is challenging. <span class="hlt">Zooplankton</span> is a key element in marine foodwebs and thus comprise an important part of overall ecosystem health. Here, we review work on <span class="hlt">zooplankton</span> indicator development using long-term data sets across the Baltic Sea and report the main findings. A suite of <span class="hlt">zooplankton</span> community metrics were evaluated as putative ecological indicators that track community state in relation to Good Environmental Status (GES) criteria with regard to eutrophication and fish feeding conditions in the Baltic Sea. On the basis of an operational definition of GES, we propose mean body mass of <span class="hlt">zooplankton</span> in the community in combination with <span class="hlt">zooplankton</span> stock measured as either abundance or biomass to be applicable as an integrated indicator that could be used within the Descriptor 4 in the Baltic Sea. These metrics performed best in predicting <span class="hlt">zooplankton</span> being in-GES when considering all datasets evaluated. However, some other metrics, such as copepod biomass, the contribution of copepods to the total <span class="hlt">zooplankton</span> biomass or biomass-based Cladocera: Copepoda ratio, were equally reliable or even superior in certain basin-specific assessments. Our evaluation suggests that in several basins of the Baltic Sea, <span class="hlt">zooplankton</span> communities currently appear to be out-of-GES, being comprised by smaller zooplankters and having lower total abundance or biomass compared to the communities during the reference conditions; however, the changes in the taxonomic structure underlying these trends vary widely across the sea basins due to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70190343','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70190343"><span>Biotic and abiotic factors influencing <span class="hlt">zooplankton</span> vertical distribution in Lake Huron</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nowicki, Carly J.; Bunnell, David B.; Armenio, Patricia M.; Warner, David M.; Vanderploeg, Henry A.; Cavaletto, Joann F.; Mayer, Christine M.; Adams, Jean V.</p> <p>2017-01-01</p> <p>The vertical distribution of <span class="hlt">zooplankton</span> can have substantial influence on trophic structure in freshwater systems, particularly by determining spatial overlap for predator/prey dynamics and influencing energy transfer. The <span class="hlt">zooplankton</span> community in some of the Laurentian Great Lakes has undergone changes in composition and declines in total biomass, especially after 2003. Mechanisms underlying these <span class="hlt">zooplankton</span> changes remain poorly understood, in part, because few studies have described their vertical distributions during daytime and nighttime conditions or evaluated the extent to which predation, resources, or environmental conditions could explain their distribution patterns. Within multiple 24-h periods during July through October 2012 in Lake Huron, we conducted daytime and nighttime sampling of <span class="hlt">zooplankton</span>, and measured food (chlorophyll-a), temperature, light (Secchi disk depth), and planktivory (biomass of Bythotrephes longimanus and Mysis diluviana). We used linear mixed models to determine whether the densities for 22 <span class="hlt">zooplankton</span> taxa varied between day and night in the epi-, meta-, and hypolimnion. For eight taxa, higher epilimnetic densities were observed at night than during the day; general linear models revealed these patterns were best explained by Mysis diluviana (four taxa), Secchi disk depth (three taxa), epilimnetic water temperature (three taxa), chlorophyll (one taxon), and biomass of Bythotrephes longimanus (one taxon). By investigating the potential effects of both biotic and abiotic variables on the vertical distribution of crustacean <span class="hlt">zooplankton</span> and rotifers, we provide descriptions of the Lake Huron <span class="hlt">zooplankton</span> community and discuss how future changes in food web dynamics or climate change may alter <span class="hlt">zooplankton</span> distribution in freshwater environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA270302','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA270302"><span>Evaluation of the <span class="hlt">Zooplankton</span> Community of Livingston Reservoir, Texas, as Related to Paddlefish Food Resources</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1993-12-01</p> <p>EVALUATION OF THE <span class="hlt">ZOOPLANKTON</span> COMMUNITY OF LIVINGSTON RESERVOIR. TEXAS, AS RELATED TO PADDLEFISH FOOD RESOURCES A Thesis by CASEY KENNETH MOORE...OF LIVINGSTON RESERVOIR, TEXAS. AS RELATED TO PADDLEFISH FOOD RESOURCES A Thesis by CASEY KENNETH MOORE Submitted to Texas A&M University in partial...Fisheries Sciences iii ABSTRACT Evaluation of the <span class="hlt">Zooplankton</span> Community of Livingston Reservoir, Texas, as Related to Paddlefish Food Resources</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BGeo...13.2927H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BGeo...13.2927H"><span>Carbon budgets for an irrigated intensively <span class="hlt">grazed</span> dairy pasture and an unirrigated winter-<span class="hlt">grazed</span> pasture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hunt, John E.; Laubach, Johannes; Barthel, Matti; Fraser, Anitra; Phillips, Rebecca L.</p> <p>2016-05-01</p> <p>Intensification of pastoral agriculture is occurring rapidly across New Zealand, including increasing use of irrigation and fertiliser application in some regions. While this enables greater gross primary production (GPP) and livestock <span class="hlt">grazing</span> intensity, the consequences for the net ecosystem carbon budget (NECB) of the pastures are poorly known. Here, we determined the NECB over one year for an irrigated, fertilised and rotationally <span class="hlt">grazed</span> dairy pasture and a neighbouring unirrigated, unfertilised, winter-<span class="hlt">grazed</span> pasture. Primary terms in the NECB calculation were: net ecosystem production (NEP), biomass carbon removed by <span class="hlt">grazing</span> cows and carbon (C) input from their excreta. Annual NEP was measured using the eddy-covariance method. Carbon removal was estimated with plate-meter measurements calibrated against biomass collections, pre- and post-<span class="hlt">grazing</span>. Excreta deposition was calculated from animal feed intake. The intensively managed pasture gained C (NECB = 103 ± 42 g C m-2 yr-1) but would have been subject to a non-significant C loss if cattle excreta had not been returned to the pasture. The unirrigated pasture was C-neutral (NECB = -13 ± 23 g C m-2 yr-1). While annual GPP of the former was almost twice that of the latter (2679 vs. 1372 g C m-2 yr-1), ecosystem respiration differed by only 68 % between the two pastures (2271 vs. 1352 g C m-2 yr-1). The ratio of GPP to the total annual water input of the irrigated pasture was 37 % greater than that of the unirrigated pasture, i.e. the former used the water input more efficiently than the latter to produce biomass. The NECB results agree qualitatively with those from many other eddy-covariance studies of <span class="hlt">grazed</span> grasslands, but they seem to be at odds with long-term carbon-stock studies of other New Zealand pastures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ECSS..199....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ECSS..199....1S"><span><span class="hlt">Zooplankton</span> variability in the subtropical estuarine system of Paranaguá Bay, Brazil, in 2012 and 2013</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salvador, Bianca; Bersano, José Guilherme F.</p> <p>2017-12-01</p> <p>Spatial and temporal dynamics of <span class="hlt">zooplankton</span> assemblages were studied in the Paranaguá Estuarine System (southern Brazil), including data from the summer (rainy) and winter (dry) periods of 2012 and 2013. <span class="hlt">Zooplankton</span> and environmental data were collected at 37 stations along the estuary and examined by multivariate methods. The results indicated significantly distinct assemblages; differences in abundance were the major source of variability, mainly over the temporal scale. The highest abundances were observed during rainy periods, especially in 2012, when the mean density reached 16378 ind.m-3. Winter assemblages showed lower densities but higher species diversity, due to the more extensive intrusion of coastal waters. Of the 14 taxonomic groups recorded, Copepoda was the most abundant and diverse (92% of total abundance and 22 species identified). The coastal copepods Acartia lilljeborgi (44%) and Oithona hebes (26%) were the most important species in both abundance and frequency, followed by the estuarine Pseudodiaptomus acutus and the neritic Temora turbinata. The results indicated strong influences of environmental parameters on the community structure, especially in response to seasonal variations. The spatial distribution of species was probably determined mainly by their preferences and tolerances for specific salinity conditions. On the other hand, the abundances were strongly related to higher water temperature and precipitation <span class="hlt">rates</span>, which can drive nutrient inputs and consequently food supply in the system, due to intense continental drainage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70118953','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70118953"><span>Lake Ontario <span class="hlt">zooplankton</span> in 2003 and 2008: Community changes and vertical redistribution</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rudstam, Lars G.; Holeck, Kristen T.; Bowen, Kelly L.; Watkins, James M.; Weidel, Brian C.; Luckey, Frederick J.</p> <p>2014-01-01</p> <p>Lake-wide <span class="hlt">zooplankton</span> surveys are critical for documenting and understanding food web responses to ecosystem change. Surveys in 2003 and 2008 during the binational intensive field year in Lake Ontario found that offshore epilimnetic crustacean <span class="hlt">zooplankton</span> declined by a factor of 12 (density) and factor of 5 (biomass) in the summer with smaller declines in the fall. These declines coincided with an increase in abundance of Bythotrephes and are likely the result of direct predation by, or behavioral responses to this invasive invertebrate predator. Whole water column <span class="hlt">zooplankton</span> density also declined from 2003 to 2008 in the summer and fall (factor of 4), but biomass only declined in the fall (factor of 2). The decline in biomass was less than the decline in density because the average size of individual <span class="hlt">zooplankton</span> increased. This was due to changes in the <span class="hlt">zooplankton</span> community composition from a cyclopoid/bosminid dominated community in 2003 to a calanoid dominated community in 2008. The increase in calanoid copepods was primarily due to the larger species Limnocalanus macrurus and Leptodiaptomus sicilis. These cold water species were found in and below the thermocline associated with a deep chlorophyll layer. In 2008, most of the <span class="hlt">zooplankton</span> biomass resided in or below the thermocline during the day. Increased importance of copepods in deeper, colder water may favor Cisco and Rainbow Smelt over Alewife because these species are better adapted to cold temperatures than Alewife.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70024890','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70024890"><span>Persistence of an unusual pelagic <span class="hlt">zooplankton</span> assemblage in a clear, mountain lake</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Larson, G.L.; Hoffman, R.L.; C. David, McIntire</p> <p>2002-01-01</p> <p>The planktonic <span class="hlt">zooplankton</span> assemblage in Mowich Lake, Mount Rainier National Park (MORA), was composed almost entirely of rotifers in 1966 and 1967. Adult pelagic crustacean taxa were rare. Their paucity was attributed to predation by kokanee salmon (Oncorhynchus nerka), which had been stocked in 1961. During a park-wide survey of 24 lakes in 1988, Mowich Lake was the only one that did not contain at least one planktonic crustacean species. Given the apparent persistence of the unusual pelagic <span class="hlt">zooplankton</span> assemblage in Mowich Lake, the first objective of this study was to document the interannual variation in the taxonomic structure of the <span class="hlt">zooplankton</span> assemblages in the lake from 1988 through 1999. A second objective was to determine if it was possible to predict the taxonomic composition of the pelagic crustacean <span class="hlt">zooplankton</span> assemblage in Mowich Lake prior to the stocking of kokanee salmon. The Mowich Lake <span class="hlt">zooplankton</span> assemblages in 1988-1999 were consistent with those in 1966 and 1967. Crustacean taxa were extremely rare, but they included most of the primary taxa collected from 23 MORA lakes surveyed in 1988. Nonetheless, the 1988 collections showed that the September rotifer assemblage in Mowich Lake was similar to 10 of the 24 lakes sampled. Seven of the 10 lakes were dominated by cladocerans, primarily Daphnia rosea and Holopedium gibberum. Therefore, it appeared that either one or both of these species may have numerically dominated the crustacean <span class="hlt">zooplankton</span> assemblage in the lake prior to 1961.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70032564','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70032564"><span><span class="hlt">Zooplankton</span> assemblages in montane lakes and ponds of Mount Rainier National Park, Washington State, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Larson, G.L.; Hoffman, R.; McIntire, C.D.; Lienkaemper, G.; Samora, B.</p> <p>2009-01-01</p> <p>Water quality and <span class="hlt">zooplankton</span> samples were collected during the ice-free periods between 1988 and 2005 from 103 oligotrophic montane lakes and ponds located in low forest to alpine vegetation zones in Mount Rainier National Park, Washington State, USA. Collectively, 45 rotifer and 44 crustacean taxa were identified. Most of the numerically dominant taxa appeared to have wide niche breadths. The average number of taxa per lake decreased with elevation and generally increased as maximum lake depths increased (especially for rotifers). With one exception, fish presence/absence did not explain the taxonomic compositions of crustacean <span class="hlt">zooplankton</span> assemblages. Many rotifer species were common members of <span class="hlt">zooplankton</span> assemblages in montane lakes and ponds in western North America, whereas the crustacean taxa were common to some areas of the west, but not others. Constraints of the environmental variables did not appear to provide strong gradients to separate the distributions of most <span class="hlt">zooplankton</span> species. This suggests that interspecific competitive interactions and stochastic processes regulate the taxonomic structures of the <span class="hlt">zooplankton</span> assemblages at the landscape level. Crustacean species that had broad niche breadths were associated with different rotifer taxa across the environmental gradients. Studies of <span class="hlt">zooplankton</span> assemblages need to address both crustacean and rotifer taxa, not one or the other.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1016168','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1016168"><span>Persistence of an unusual pelagic <span class="hlt">zooplankton</span> assemblage in a clear mountain lake</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Larson, Gary L.; Hoffman, Robert L.; McIntire, C.D.</p> <p>2002-01-01</p> <p>The planktonic <span class="hlt">zooplankton</span> assemblage in Mowich Lake, Mount Rainier National Park (MORA), was composed almost entirely of rotifers in 1966 and 1967. Adult pelagic crustacean taxa were rare. Their paucity was attributed to predation by kokanee salmon (Oncorhynchus nerka), which had been stocked in 1961. During a park-wide survey of 24 lakes in 1988, Mowich Lake was the only one that did not contain at least one planktonic crustacean species. Given the apparent persistence of the unusual pelagic <span class="hlt">zooplankton</span> assemblage in Mowich Lake, the first objective of this study was to document the interannual variation in the taxonomic structure of the <span class="hlt">zooplankton</span> assemblages in the lake from 1988 through 1999. A second objective was to determine if it was possible to predict the taxonomic composition of the pelagic crustacean <span class="hlt">zooplankton</span> assemblage in Mowich Lake prior to the stocking of kokanee salmon. The Mowich Lake <span class="hlt">zooplankton</span> assemblages in 1988a??1999 were consistent with those in 1966 and 1967. Crustacean taxa were extremely rare, but they included most of the primary taxa collected from 23 MORA lakes surveyed in 1988. Nonetheless, the 1988 collections showed that the September rotifer assemblage in Mowich Lake was similar to 10 of the 24 lakes sampled. Seven of the 10 lakes were dominated by cladocerans, primarily Daphnia rosea and Holopedium gibberum. Therefore, it appeared that either one or both of these species may have numerically dominated the crustacean <span class="hlt">zooplankton</span> assemblage in the lake prior to 1961.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18243271','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18243271"><span>Microcystin production by Microcystis aeruginosa exposed to different stages of herbivorous <span class="hlt">zooplankton</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jang, Min-Ho; Ha, Kyong; Takamura, Noriko</p> <p>2008-04-01</p> <p>Microcystin (MC) production by four monoclonal Microcystis aeruginosa strains was evaluated in response to infochemicals (indirect exposure) released from different stages of herbivorous <span class="hlt">zooplankton</span> (neonate/juvenile and adult Daphnia magna and Moina macrocopa). The intracellular MC and extracellular MC concentrations were significantly different among the control and treatments with <span class="hlt">zooplankton</span> culture media filtrates (p<0.05), and in most cases MC production was significantly higher (p<0.05) in strains exposed to infochemicals released from adult <span class="hlt">zooplankton</span> rather than those of neonate/juvenile <span class="hlt">zooplankton</span> in four strains of M. aeruginosa. Compared to intracellular MC (385.0-5598.6microg g(-1)DW), very low concentrations of extracellular MC (9.9-737.6microg ml(-1)) were released, but both showed similar temporal patterns over the course of the experiment. This result might be attributed to the fact that adult <span class="hlt">zooplankton</span> produced more infochemical signals than equal numbers of smaller juveniles and neonates. It is the first study to provide evidence that MC production might be impacted by infochemicals released from different stages of <span class="hlt">zooplankton</span>, mediated with physiological characteristics, body size, and feeding habits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME14E0670S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME14E0670S"><span>DNA Barcoding of <span class="hlt">Zooplankton</span> in the Hampton Roads Area: A Biodiversity Assessment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salcedo, A.; Rodríguez, Á. E.; Gibson, D. M.</p> <p>2016-02-01</p> <p>The study of <span class="hlt">zooplankton</span> biodiversity and distribution is crucial to understand oceanic ecosystems and anticipate the effects of climate change. Previously, identification of <span class="hlt">zooplankton</span> relied in morphological identification employed by expert taxonomists. DNA barcoding, a technique that uses the mitochondrial DNA (mtDNA) Cytochrome Oxidase 1 (CO1) gene is widely used for taxonomic identification. Thus, this molecular technique will be used to begin a detailed characterization of <span class="hlt">zooplankton</span> diversity, abundance and community structure in the Hampton Roads Area (HRA). Stations 1 (Jones Creek) and 3 (lower Chesapeake Bay) were sampled in June 19, 2015. Stations 1, 2 (James River), and 3 were sampled in September 2015. <span class="hlt">Zooplankton</span> samples were collected in triplicates with a 0.5m, 200 µm mesh net. Physical parameters (dissolved oxygen, salinity, temperature and, water transparency) were measured. Species identified as Opistonema oglinum (Atlantic Thread Herring) and Paracalanus parvus copepods were found at station 3; Anchoa mitchilli and Acartia tonsa copepods were found at stations 1 and 3. This study indicates that mtDNA-CO1 barcoding is suitable to identify <span class="hlt">zooplankton</span> to the species level and helps validate DNA barcoding as a faster, more accurate taxonomic approach. The long term objective of this project is to provide a comprehensive assessment of <span class="hlt">zooplankton</span> in the HRA and to generate a reference record for broad monitoring programs; vital for a better understanding and management of ecologically and commercially important species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME14E0657E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME14E0657E"><span>Seasonal Phenology of <span class="hlt">Zooplankton</span> Composition in the Southeastern Bering Sea, 2008-2010</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eisner, L. B.; Pinchuk, A. I.; Harpold, C.; Siddon, E. C.; Mier, K.</p> <p>2016-02-01</p> <p>The availability of large crustacean <span class="hlt">zooplankton</span> prey is critical to the condition and survival of forage fish (e.g., age-0 Walleye Pollock), sea birds, and marine mammals in the eastern Bering Sea. <span class="hlt">Zooplankton</span> community composition and abundances of large lipid-rich copepods (e.g., Calanus spp.) have been evaluated for single seasons, but few studies have investigated seasonal variations in this region. Here, we investigate seasonal changes in taxa (community structure), stage composition (where appropriate), and diversity from spring through late summer/early fall over three consecutive colder than average years. <span class="hlt">Zooplankton</span> taxonomic samples were collected with oblique bongo tows over the water column during spring (April-May), mid-summer (June-July) and late summer/early fall (August-September) across the southeastern Bering Sea shelf in 2008-2010. <span class="hlt">Zooplankton</span> abundances were evaluated by oceanographic region, season and year, and related to water mass characteristics (temperature and salinity) and other environmental drivers. Finally, <span class="hlt">zooplankton</span> phenology was compared to changes in forage fish composition to determine potential overlap of fish predators and <span class="hlt">zooplankton</span> prey.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70094775','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70094775"><span>Terrestrial carbon is a resource, but not a subsidy, for lake <span class="hlt">zooplankton</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kelly, Patrick T.; Solomon, Christopher T.; Weidel, Brian C.; Jones, Stuart E.</p> <p>2014-01-01</p> <p>Inputs of terrestrial organic carbon (t-OC) into lakes are often considered a resource subsidy for aquatic consumer production. Although there is evidence that terrestrial carbon can be incorporated into the tissues of aquatic consumers, its ability to enhance consumer production has been debated. Our research aims to evaluate the net effect of t-OC input on <span class="hlt">zooplankton</span>. We used a survey of <span class="hlt">zooplankton</span> production and resource use in ten lakes along a naturally occurring gradient of t-OC concentration to address these questions. Total and group-specific <span class="hlt">zooplankton</span> production was negatively related to t-OC. Residual variation in <span class="hlt">zooplankton</span> production that was not explained by t-OC was negatively related to terrestrial resource use (allochthony) by <span class="hlt">zooplankton</span>. These results challenge the designation of terrestrial carbon as a resource subsidy; rather, the negative effect of reduced light penetration on the amount of suitable habitat and the low resource quality of t-OC appear to diminish <span class="hlt">zooplankton</span> production. Our findings suggest that ongoing continental-scale increases in t-OC concentrations of lakes will likely have negative impacts on the productivity of aquatic food webs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME23B..01R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME23B..01R"><span>Overheated and Out of Breath: Temperature Regulation of Respiration and Oxygen Supply in Coastal <span class="hlt">Zooplankton</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roman, M.; Elliott, D. T.; Pierson, J. J.</p> <p>2016-02-01</p> <p>Increasing global coastal hypoxia occurs under a large range of temperature and salinity conditions. Temperature directly influences oxygen solubility in seawater as well as the oxygen demand of <span class="hlt">zooplankton</span>, thus oxygen concentration alone is not sufficient to categorize the biological impact of hypoxia for pelagic organisms. To effectively assess the impacts of hypoxic stress on <span class="hlt">zooplankton</span> habitat space and production, it is necessary to consider the effects of temperature on both oxygen availability and <span class="hlt">zooplankton</span> metabolism. Our analysis and modeling evaluate available oxygen (partial pressure and concentration) in the context of ambient temperature conditions and <span class="hlt">zooplankton</span> oxygen demand. We will present allometric models, accounting for both body size and temperature that predict temperature-dependent oxygen supply and demand in coastal <span class="hlt">zooplankton</span>. Our goal is to develop generalized, functional relationships that describe and quantify the interactive effects of temperature and low oxygen on coastal <span class="hlt">zooplankton</span> that can lead to improved size-structured models that serve to predict impacts of increasing coastal hypoxia on pelagic food webs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.3202G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.3202G"><span>Examining shifts in <span class="hlt">zooplankton</span> community as a response of environmental change in Lakes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghadouani, Anas; Mines, Conor; Legendre, Pierre; Yan, Norman</p> <p>2014-05-01</p> <p>We examined 20 years of <span class="hlt">zooplankton</span> samples from Harp Lake for shifts in <span class="hlt">zooplankton</span> variability following invasion by <span class="hlt">zooplankton</span> predator Bythotrephes longimanus, using organism body size—as measured at high resolution by Laser Optical Plankton Counter (LOPC)—as the primary metric of investigation. A period of transitory high variability in the 2yr post-invasion was observed for both body size compositional variability and aggregate variability metrics, with both measures of variability shifting from low or intermediate to high variability immediately following invasion, before shifting again to intermediate variability, 2 yr post-invasion. Aggregate and compositional variability dynamics were also considered in combination over the study period, revealing that the period of transitory high variability coincided with a shift from a community-wide stasis variability pattern to one of asynchrony, before a shift back to stasis 2 yr post-invasion. These dynamics were related to changes in the significant <span class="hlt">zooplankton</span> species within the Harp Lake community over the pre- and post- invasion periods, and are likely to be indicative of changes in the stability in the <span class="hlt">zooplankton</span> community following invasion by Bythotrephes. The dual consideration of aggregate and compositional variability as measured by LOPC was found to provide a valuable means to assess the ecological effects of biological invasion on <span class="hlt">zooplankton</span> communities as a whole, extending our knowledge of the effects of invasion beyond that already revealed through more traditional taxonomic investigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PrOce..69..318F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PrOce..69..318F"><span><span class="hlt">Zooplankton</span> and the oceanography of the eastern tropical Pacific: A review</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández-Álamo, María Ana; Färber-Lorda, Jaime</p> <p>2006-05-01</p> <p>We review the spatial and temporal patterns of <span class="hlt">zooplankton</span> in the eastern tropical Pacific Ocean and relationships with oceanographic factors that affect <span class="hlt">zooplankton</span> distribution, abundance and trophic relationships. Large-scale spatial patterns of some <span class="hlt">zooplankton</span> groups show broad coincidence with surface water masses, circulation, and upwelling regions, in agreement with an ecological and dynamic partitioning of the pelagic ecosystem. The papers reviewed and a new compilation of <span class="hlt">zooplankton</span> volume data at large-scale show that abundance patterns of <span class="hlt">zooplankton</span> biomass have their highest values in the upwelling regions, including the Gulf of Tehuantepec, the Costa Rica Dome, the equatorial cold tongue, and the coast of Peru. Some of the first studies of <span class="hlt">zooplankton</span> vertical distribution were done in this region, and a general review of the topic is presented. The possible physiological implications of vertical migration in <span class="hlt">zooplankton</span> and the main hypotheses are described, with remarks on the importance of the oxygen minimum zone (OMZ) as a barrier to both the vertical distribution and migration of <span class="hlt">zooplankton</span> in the region. Recent results, using multiple-net gear, show that vertical distribution is more complex than previously thought. There are some well-adapted species that do live and migrate within the OMZ. Temporal patterns are reviewed and summarized with historical data. Seasonal variations in <span class="hlt">zooplankton</span> biomass follow productivity cycles in upwelling areas. No <span class="hlt">zooplankton</span> time series exist to resolve ENSO effects in oceanic regions, but some El Niño events have had effects in the Peru Current ecosystem. Multidecadal periods of up to 50 years show a shift from a warm sardine regime with a low <span class="hlt">zooplankton</span> biomass to a cool anchovy regime in the eastern Pacific with higher <span class="hlt">zooplankton</span> biomasses. However, <span class="hlt">zooplankton</span> volume off Peru has remained at low values since the 1972 El Niño, a trend opposite to that of anchoveta biomass since 1984. Studies of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28188321','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28188321"><span>Is Aluminum Innocuous to <span class="hlt">Zooplankton</span> at pH Below 6?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>García-García, G; Jiménez-Contreras, J; Vargas-Hernández, A A; Nandini, S; Sarma, S S S</p> <p>2017-04-01</p> <p>Aluminum (Al) use has increased greatly during the last two decades, yet little information is available on its toxic effects in relation to pH particularly on <span class="hlt">zooplankton</span>. In this work, we determined the acute toxicity (LC 50 ) and life table responses for Moina micrura exposed to 0.008, 0.016 and 0.08 mg of Al L -1 at pH of 5, 6 and 7. The age-specific survivorship and reproduction showed a steep decline (80% mortality by the second day) at pH 5, independent of Al level. Both gross and net reproductive <span class="hlt">rates</span> were significantly lower at pH 6 compared to pH 7, regardless of Al concentration. At pH 7 the <span class="hlt">rate</span> of population increase of M. micrura was not significantly influenced by the Al level, while at pH 6 it was significantly lower (p < 0.05), suggesting that M. micrura is sensitive to changes in Al under slightly acidic conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70170570','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70170570"><span>Developmental instability and fitness in Periploca laevigata experiencing <span class="hlt">grazing</span> disturbance</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Alados, C.L.; Giner, M.L.; Dehesa, L.; Escos, J.; Barroso, F.; Emlen, J.M.; Freeman, D.C.</p> <p>2002-01-01</p> <p>We investigated the sensitivity of developmental instability measurements (leaf fluctuating asymmetry, floral radial asymmetry, and shoot translational asymmetry) to a long‐standing natural stress (<span class="hlt">grazing</span>) in a palatable tannin‐producing shrub (Periploca laevigata Aiton). We also assessed the relationship between these measures of developmental instability and fitness components (growth and floral production). Developmental instability, measured by translational asymmetry, was the most accurate estimator of a plant’s condition and, consequently, environmental stress. Plants with less translational asymmetry grew more and produced more flowers. Plants from the medium‐<span class="hlt">grazed</span> population were developmentally more stable, as estimated by translational and floral asymmetry, than either more heavily or more lightly <span class="hlt">grazed</span> populations. Leaf fluctuating asymmetry was positively correlated with tannin concentration. The pattern of internode growth also responded to <span class="hlt">grazing</span> impact. Plants under medium to heavy <span class="hlt">grazing</span> pressure accelerated early growth and consequently escaped herbivory later in the season, i.e., at the beginning of the spring, when <span class="hlt">grazing</span> activity was concentrated in herbaceous plants. Periploca laevigata accelerated growth and finished growing sooner than in the other <span class="hlt">grazing</span> treatment. Thus, its annual growth was more mature and less palatable later in the season when grazers typically concentrate on shrubs. The reduction of developmental instability under medium <span class="hlt">grazing</span> is interpreted as a direct effect of <span class="hlt">grazing</span> and not as the release from competition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70129037','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70129037"><span>Livestock <span class="hlt">grazing</span> and the desert tortoise in the Mojave Desert</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Oldemeyer, John L.</p> <p>1994-01-01</p> <p>A large part of the Mojave Desert is not in pristine condition, and some current conditions can be related to past <span class="hlt">grazing</span>-management practices. No information could be found on densities of the desert tortoise (Gopherus agassizii) or on vegetative conditions of areas that had not been <span class="hlt">grazed</span> to allow managers a comparison of range conditions with data on tortoises. Experimental information to assess the effect of livestock <span class="hlt">grazing</span> on tortoises is lacking, and researchers have not yet examined whether the forage that remains after <span class="hlt">grazing</span> is sufficient to meet the nutritional needs of desert tortoises.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713278K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713278K"><span>Reindeer <span class="hlt">grazing</span> in subarctic boreal forest - influences on the soil carbon dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koster, Kajar; Berninger, Frank; Köster, Egle; Pumpanen, Jukka</p> <p>2015-04-01</p> <p>, four 0.5 x 0.5 m ground vegetation squares were established for species composition and recovery measurements. The squares were photographed for ground vegetation coverage analyses and definition of species composition. Ground vegetation biomass was determined from 4 sample squares (0.2 x 0.2 m) located systematically inside the circular sample plots (close to the ground vegetation squares). For soil C content measurements 5 soil cores (150 mm in length and 50 mm in diameter) were taken from every sample plot in Värriö and in Sodankylä. The soil cores were divided according to the morphological soil horizons; to litter and organic layer (F-horizon) and humus layer (O-horizon). The layers in mineral soil were divided to eluvial (A-horizon) and illuvial (B-horizon), and sieved. All roots were separated for root biomass calculations. The soil C content was measured with an elemental analyser (varioMAX CN elemental analyser, Elementar Analysensysteme GmbH, Germany). The soil respiration <span class="hlt">rates</span> were measured only in Värriö study areas. In order to determine the CO2 efflux from soil to atmosphere, manual chamber measurements with a diffusion type CO2 probe (GMP343), were performed on 6 collars at each sample plot from June till September (five times per collar) at measuring intervals of two weeks. Soil microbial biomass was measured from five soil samples (soil from lower humus layer) per sample plot in Värriö. To determine the soil microbial C biomass (Cmic) and soil microbial N biomass (Nmic) chloroform fumigation direct extraction method was used. The average soil temperatures during the growing season (from June till September) were similar in all sample plots in Värriö, ranging from 10.9 to 11.5 ° C. There were also no differences between daily average temperatures or soil moisture between <span class="hlt">grazed</span> and ungrazed areas. There was no statistically significant effect of reindeer <span class="hlt">grazing</span> on soil C content, although it was mainly higher in <span class="hlt">grazed</span> area compared to the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BGeo...13.1977H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BGeo...13.1977H"><span>Dead zone or oasis in the open ocean? <span class="hlt">Zooplankton</span> distribution and migration in low-oxygen modewater eddies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hauss, Helena; Christiansen, Svenja; Schütte, Florian; Kiko, Rainer; Edvam Lima, Miryam; Rodrigues, Elizandro; Karstensen, Johannes; Löscher, Carolin R.; Körtzinger, Arne; Fiedler, Björn</p> <p>2016-04-01</p> <p> copepods, euphausiids); (ii) migration to the shallow OMZ core during daytime, but paying O2 debt at the surface at nighttime (e.g. siphonophores, Oncaea spp., eucalanoid copepods); (iii) residing in the shallow OMZ day and night (e.g. ostracods, polychaetes); and (iv) DVM through the shallow OMZ from deeper oxygenated depths to the surface and back. For strategy (i), (ii) and (iv), compression of the habitable volume in the surface may increase prey-predator encounter <span class="hlt">rates</span>, rendering <span class="hlt">zooplankton</span> and micronekton more vulnerable to predation and potentially making the eddy surface a foraging hotspot for higher trophic levels. With respect to long-term effects of ocean deoxygenation, we expect avoidance of the mesopelagic OMZ to set in if oxygen levels decline below approximately 20 µmol O2 kg-1. This may result in a positive feedback on the OMZ oxygen consumption <span class="hlt">rates</span>, since <span class="hlt">zooplankton</span> and micronekton respiration within the OMZ as well as active flux of dissolved and particulate organic matter into the OMZ will decline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15245111','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15245111"><span>Step edge sputtering yield at <span class="hlt">grazing</span> incidence ion bombardment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hansen, Henri; Polop, Celia; Michely, Thomas; Friedrich, Andreas; Urbassek, Herbert M</p> <p>2004-06-18</p> <p>The surface morphology of Pt(111) was investigated by scanning tunneling microscopy after 5 keV Ar+ ion bombardment at <span class="hlt">grazing</span> incidence in dependence of the ion fluence and in the temperature range between 625 and 720 K. The average erosion <span class="hlt">rate</span> was found to be strongly dependent on the ion fluence and the substrate temperature during bombardment. This dependence is traced back to the variation of step concentration with temperature and fluence. We develop a simple model allowing us to determine separately the constant sputtering yields for terraces and for impact area stripes in front of ascending steps. The experimentally determined yield of these stripes--the step-edge sputtering yield--is in excellent agreement with our molecular dynamics simulations performed for the experimental situation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME51B..06D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME51B..06D"><span>Estimating Diversity of Florida Keys <span class="hlt">Zooplankton</span> Using New Environmental DNA Methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Djurhuus, A.; Goldsmith, D. B.; Sawaya, N. A.; Breitbart, M.</p> <p>2016-02-01</p> <p><span class="hlt">Zooplankton</span> are of great importance in marine food webs, where they serve to link the phytoplankton and bacteria with higher trophic levels. <span class="hlt">Zooplankton</span> are a diverse group containing molluscs, crustaceans, fish larvae and many other taxa. The sheer number of species and often minor morphological distinctions between species makes it challenging and exceptionally time consuming to identify the species composition of marine <span class="hlt">zooplankton</span> samples. As a part of the Marine Biodiversity Observation Network (MBON) project, we have developed and groundtruthed an alternative, relatively time-efficient method for <span class="hlt">zooplankton</span> identification using environmental DNA (eDNA). Samples were collected from Molasses reef, Looe Key, and Western Sambo along the Florida Keys from five bi-monthly cruises on board the RV Walton Smith. Samples were collected for environmental DNA (eDNA) by filtering 1 L of water on to a 0.22 µm filter and <span class="hlt">zooplankton</span> samples were collected using nets with three mesh sizes (64μm, 200μm, and 500μm) to catch different size fractions. Half of <span class="hlt">zooplankton</span> samples were fixed in 70% ethanol and half in 10% formalin, for DNA extraction and morphological identification, respectively. Individuals representing visually abundant taxa were picked into individual wells for PCR with universal 18S rRNA gene primers and subsequent sequencing to build a reference barcode database for <span class="hlt">zooplankton</span> species commonly found in the study region. PCR and Illumina MiSeq next generation sequencing was applied to the eDNA extracted from the 0.22 μm filters and sequences were be compared to our local custom database as well as publicly available databases to determine <span class="hlt">zooplankton</span> community composition. Finally, composition and diversity analyses were performed to compare results obtained with the new eDNA approach to standard morphological classification of <span class="hlt">zooplankton</span> communities. Results show that the eDNA approach can enable the determination of <span class="hlt">zooplankton</span> diversity through</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23360214','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23360214"><span>Effects of rotational and continuous <span class="hlt">grazing</span> on herbage quality, feed intake and performance of sheep on a semi-arid grassland steppe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hao, Jun; Dickhoefer, Uta; Lin, Lijun; Müller, Katrin; Glindemann, Thomas; Schönbach, Philipp; Schiborra, Anne; Wang, Chengjie; Susenbeth, Andreas</p> <p>2013-02-01</p> <p>Compared to continuous <span class="hlt">grazing</span> (CG), rotational <span class="hlt">grazing</span> (RG) increases herbage production and thereby the resilience of grasslands to intensive <span class="hlt">grazing</span>. Results on feed intake and animal performance, however, are contradictory. Hence, the objective of the study was to determine the effects of RG and CG on herbage mass, digestibility of ingested organic matter (dOM), organic matter intake (OMI) and live weight gain (LWG) of sheep in the Inner Mongolian steppe, China. During June-September 2005-2008, two 2-ha plots were used for each <span class="hlt">grazing</span> system. In RG, plots were divided into four 0.5-ha paddocks that were <span class="hlt">grazed</span> for 10 days each at a moderate stocking <span class="hlt">rate</span>. Instead, CG sheep <span class="hlt">grazed</span> the whole plots throughout the entire <span class="hlt">grazing</span> season. At the beginning of every month, dOM was estimated from faecal crude protein concentration. Faeces excretion was determined using titanium dioxide in six sheep per plot. The animals were weighed every month to determine their LWG. Across the years, herbage mass did not differ between systems (p = 0.820). However, dOM, OMI and LWG were lower in RG than in CG (p ≤ 0.005). Thus, our study showed that RG does not improve herbage growth, feed intake and performance of sheep and suggests that stocking <span class="hlt">rates</span> rather than management system determine the ecological sustainability of pastoral livestock systems in semi-arid environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012DSRI...62..111B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012DSRI...62..111B"><span>Summertime <span class="hlt">grazing</span> impact of the dominant macrozooplankton off the Western Antarctic Peninsula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bernard, Kim S.; Steinberg, Deborah K.; Schofield, Oscar M. E.</p> <p>2012-04-01</p> <p>The Western Antarctic Peninsula (WAP) is a region of rapid climate change that is altering plankton community structure. To investigate how these changes may impact carbon and energy transfer in the pelagic food web, <span class="hlt">grazing</span> <span class="hlt">rates</span> of the five dominant macrozooplankton species (euphausiids Euphausia superba, Euphausia crystallorophias, and Thysanöessa macrura; the pteropod Limacina helicina, and the salp Salpa thompsoni) in the WAP were measured in January 2009 and 2010 as part of the Palmer Antarctica Long-Term Ecological Research (LTER) study. Measurements were made across the coastal-shelf-offshore and north-south gradients of the LTER survey grid. Highest <span class="hlt">grazing</span> <span class="hlt">rates</span> occurred offshore in both years, and in the south during 2009 and north during 2010, all associated with the presence of large localized salp blooms. During both years, E. superba was the major grazer at the coast, while S. thompsoni dominated <span class="hlt">grazing</span> offshore. L. helicina was an important grazer throughout the study area during both years, but especially so over the shelf during 2009. During 2009, there was little difference in the relative importance of the macrozooplankton grazers along the north-south gradient. The presence of a salp bloom in the north during 2010, though, resulted in a distinct shift in the relative importance of major grazers from the euphausiids and L. helicina in the south to salps in the north. <span class="hlt">Grazing</span> impact was low in coastal waters (≤0.3% of phytoplankton standing stock and ≤0.6% of primary productivity). In contrast, in the offshore waters, where salp blooms were observed, <span class="hlt">grazing</span> impacts of up to 30% of standing stock and 169% of primary productivity were recorded. If S. thompsoni and L. helicina continue to expand their ranges and increase in abundance, the associated shift in the food web dynamics of the WAP will alter the regional flow of carbon through the WAP food webs and the export of carbon to depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=247703','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=247703"><span><span class="hlt">Grazing</span> Stategy To Decrease Dietary Crude Protien Wastage In Stocker Calves <span class="hlt">Grazing</span> Winter Wheat Pasture.</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Annual cool-season grasses, primarily winter wheat, provide high quality forage for stocker calves during the fall, winter and spring <span class="hlt">grazing</span> seasons for stocker enterprises in the southern Great Plains. The crude protein (CP) content of winter wheat pasture exceeds the stocker calf’s daily CP requi...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5082622','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5082622"><span>Wild Herbivore <span class="hlt">Grazing</span> Enhances Insect Diversity over Livestock <span class="hlt">Grazing</span> in an African Grassland System</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Roets, Francois; Samways, Michael J.</p> <p>2016-01-01</p> <p>Southern Africa’s grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural <span class="hlt">grazing</span> dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild <span class="hlt">grazed</span> EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic <span class="hlt">grazing</span>. Furthermore, species composition shows significant differences between the two <span class="hlt">grazing</span> systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs. PMID:27783685</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27783685','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27783685"><span>Wild Herbivore <span class="hlt">Grazing</span> Enhances Insect Diversity over Livestock <span class="hlt">Grazing</span> in an African Grassland System.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pryke, James S; Roets, Francois; Samways, Michael J</p> <p>2016-01-01</p> <p>Southern Africa's grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural <span class="hlt">grazing</span> dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild <span class="hlt">grazed</span> EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic <span class="hlt">grazing</span>. Furthermore, species composition shows significant differences between the two <span class="hlt">grazing</span> systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24507886','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24507886"><span>A spatial risk assessment of bighorn sheep extirpation by <span class="hlt">grazing</span> domestic sheep on public lands.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carpenter, Tim E; Coggins, Victor L; McCarthy, Clinton; O'Brien, Chans S; O'Brien, Joshua M; Schommer, Timothy J</p> <p>2014-04-01</p> <p>Bighorn sheep currently occupy just 30% of their historic distribution, and persist in populations less than 5% as abundant overall as their early 19th century counterparts. Present-day recovery of bighorn sheep populations is in large part limited by periodic outbreaks of respiratory disease, which can be transmitted to bighorn sheep via contact with domestic sheep <span class="hlt">grazing</span> in their vicinity. In order to assess the viability of bighorn sheep populations on the Payette National Forest (PNF) under several alternative proposals for domestic sheep <span class="hlt">grazing</span>, we developed a series of interlinked models. Using telemetry and habitat data, we characterized herd home ranges and foray movements of bighorn sheep from their home ranges. Combining foray model movement estimates with known domestic sheep <span class="hlt">grazing</span> areas (allotments), a Risk of Contact Model estimated bighorn sheep contact <span class="hlt">rates</span> with domestic sheep allotments. Finally, we used demographic and epidemiologic data to construct population and disease transmission models (Disease Model), which we used to estimate bighorn sheep persistence under each alternative <span class="hlt">grazing</span> scenario. Depending on the probability of disease transmission following interspecies contact, extirpation probabilities for the seven bighorn sheep herds examined here ranged from 20% to 100%. The Disease Model allowed us to assess the probabilities that varied domestic sheep management scenarios would support persistent populations of free-ranging bighorn sheep. Copyright © 2014 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4260134','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4260134"><span>Root traits predict decomposition across a landscape-scale <span class="hlt">grazing</span> experiment</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Smith, Stuart W; Woodin, Sarah J; Pakeman, Robin J; Johnson, David; van der Wal, René</p> <p>2014-01-01</p> <p>Root litter is the dominant soil carbon and nutrient input in many ecosystems, yet few studies have considered how root decomposition is regulated at the landscape scale and how this is mediated by land-use management practices. Large herbivores can potentially influence below-ground decomposition through changes in soil microclimate (temperature and moisture) and changes in plant species composition (root traits). To investigate such herbivore-induced changes, we quantified annual root decomposition of upland grassland species in situ across a landscape-scale livestock <span class="hlt">grazing</span> experiment, in a common-garden experiment and in laboratory microcosms evaluating the influence of key root traits on decomposition. Livestock <span class="hlt">grazing</span> increased soil temperatures, but this did not affect root decomposition. <span class="hlt">Grazing</span> had no effect on soil moisture, but wetter soils retarded root decomposition. Species-specific decomposition <span class="hlt">rates</span> were similar across all <span class="hlt">grazing</span> treatments, and species differences were maintained in the common-garden experiment, suggesting an overriding importance of litter type. Supporting this, in microcosms, roots with lower specific root area (m2 g−1) or those with higher phosphorus concentrations decomposed faster. Our results suggest that large herbivores alter below-ground carbon and nitrogen dynamics more through their effects on plant species composition and associated root traits than through effects on the soil microclimate. PMID:24841886</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24671589','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24671589"><span>Green leaf allowance and dairy ewe performance <span class="hlt">grazing</span> on tropical pasture.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Souza, J; Batistel, F; Ticiani, E; Sandri, E C; Pedreira, C G S; Oliveira, D E</p> <p>2014-06-01</p> <p>The objective of this study was to explain the influence of green leaf allowance levels on the performance of dairy ewes <span class="hlt">grazing</span> a tropical grass. Seventy-two lactating ewes <span class="hlt">grazed</span> Aruana guineagrass (Panicum maximum Jacq. cv. Aruana) for 80 d. The treatments were 4 daily levels of green leaf allowance (GLA) on a DM basis corresponding to 4, 7, 10, and 13 kg DM/100 kg BW, which were named low, medium-low, medium-high, and high level, respectively. The experimental design was completely randomized with 3 replications. During the experimental period, 4 <span class="hlt">grazing</span> cycles were evaluated in a rotational stocking <span class="hlt">grazing</span> method (4 d of <span class="hlt">grazing</span> and 16 d of rest). There was a linear effect of GLA on forage mass, and increasing GLA resulted in increased total leaf mass, reaching an asymptotic plateau around the medium-high GLA level. The stem mass increased with increased GLA, and a pronounced increase was observed between medium-high and high GLAs. Increasing GLA increased both forage disappearance <span class="hlt">rate</span> and postgrazing forage mass. Leaf proportion increased with GLA, peaking at the medium-high level, and the opposite occurred for stem proportions, which reduced until medium-high GLA level, followed by an increase on high GLA. Forage CP decreased linearly with GLA, and increasing GLA from low to high reduced CP content by 31%. On the other hand, NDF increased 14% and ADF increased 26%, both linearly in response to greater GLA levels. Total digestible nutrients decreased linearly by 8% when GLA increased from low to high level. Milk yield increased, peaking at medium-high GLA (1.75 kg ewe(-1) d(-1)) and decreased at high GLA level (1.40 kg ewe(-1) d(-1)). Milk composition was not affected by the GLA levels. There was a reduction in stocking <span class="hlt">rate</span> from 72 to 43 ewes/ha when GLA increased from low to high level. Productivity (milk yield kg ha(-1) d(-1)) increased as GLA increased, peaking at medium-low level (115 kg ha(-1) d(-1)). Although this tropical grass showed the same</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS43B2040T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS43B2040T"><span>Modeling the effects of free-living marine bacterial community composition on heterotrophic remineralization <span class="hlt">rates</span> and biogeochemical carbon cycling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Teel, E.; Liu, X.; Cram, J. A.; Sachdeva, R.; Fuhrman, J. A.; Levine, N. M.</p> <p>2016-12-01</p> <p>Global oceanic ecosystem models either disregard fluctuations in heterotrophic bacterial remineralization or vary remineralization as a simple function of temperature, available carbon, and nutrient limitation. Most of these models were developed before molecular techniques allowed for the description of microbial community composition and functional diversity. Here we investigate the impact of a dynamic heterotrophic community and variable remineralization <span class="hlt">rates</span> on biogeochemical cycling. Specifically, we integrated variable microbial remineralization into an ecosystem model by utilizing molecular community composition data, association network analysis, and biogeochemical <span class="hlt">rate</span> data from the San Pedro Ocean Time-series (SPOT) station. Fluctuations in free-living bacterial community function and composition were examined using monthly environmental and biological data collected at SPOT between 2000 and 2011. On average, the bacterial community showed predictable seasonal changes in community composition and peaked in abundance in the spring with a one-month lag from peak chlorophyll concentrations. Bacterial growth efficiency (BGE), estimated from bacterial production, was found to vary widely at the site (5% to 40%). In a multivariate analysis, 47.6% of BGE variability was predicted using primary production, bacterial community composition, and temperature. A classic Nutrient-Phytoplankton-<span class="hlt">Zooplankton</span>-Detritus model was expanded to include a heterotroph module that captured the observed relationships at the SPOT site. Results show that the inclusion of dynamic bacterial remineralization into larger oceanic ecosystem models can significantly impact microzooplankton <span class="hlt">grazing</span>, the duration of surface phytoplankton blooms, and picophytoplankton primary production <span class="hlt">rates</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4550388','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4550388"><span><span class="hlt">Grazing</span> Affects Exosomal Circulating MicroRNAs in Cattle</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Muroya, Susumu; Ogasawara, Hideki; Hojito, Masayuki</p> <p>2015-01-01</p> <p>Circulating microRNAs (c-miRNAs) are associated with physiological adaptation to acute and chronic aerobic exercise in humans. To investigate the potential effect of <span class="hlt">grazing</span> movement on miRNA circulation in cattle, here we profiled miRNA expression in centrifugally prepared exosomes from the plasma of both <span class="hlt">grazing</span> and housed Japanese Shorthorn cattle. Microarray analysis of the c-miRNAs resulted in detection of a total of 231 bovine exosomal miRNAs in the plasma, with a constant expression level of let-7g across the duration and cattle groups. Expression of muscle-specific miRNAs such as miR-1, miR-133a, miR-206, miR-208a/b, and miR-499 were undetectable, suggesting the mildness of <span class="hlt">grazing</span> movement as exercise. According to validation by quantitative RT-PCR, the circulating miR-150 level in the <span class="hlt">grazing</span> cattle normalized by the endogenous let-7g level was down-regulated after 2 and 4 months of <span class="hlt">grazing</span> (P < 0.05), and then its levels in housed and <span class="hlt">grazing</span> cattle equalized when the <span class="hlt">grazing</span> cattle were returned to a housed situation. Likewise, the levels of miR-19b, miR-148a, miR-221, miR-223, miR-320a, miR-361, and miR-486 were temporarily lowered in the cattle at 1 and/or 2 month of <span class="hlt">grazing</span> compared to those of the housed cattle (P < 0.05). In contrast, the miR-451 level was up-regulated in the <span class="hlt">grazing</span> cattle at 2 months of <span class="hlt">grazing</span> (P = 0.044). The elevation of miR-451 level in the plasma was coincident with that in the biceps femoris muscle of the <span class="hlt">grazing</span> cattle (P = 0.008), which suggests the secretion or intake of miR-451 between skeletal muscle cells and circulation during <span class="hlt">grazing</span>. These results revealed that exosomal c-miRNAs in cattle were affected by <span class="hlt">grazing</span>, suggesting their usefulness as molecular <span class="hlt">grazing</span> markers and functions in physiological adaptation of <span class="hlt">grazing</span> cattle associated with endocytosis, focal adhesion, axon guidance, and a variety of intracellular signaling, as predicted by bioinformatic analysis. PMID:26308447</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28105571','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28105571"><span>Metal stress in <span class="hlt">zooplankton</span> diapause production: post-hatching response.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Aránguiz-Acuña, Adriana; Pérez-Portilla, Pablo</p> <p>2017-04-01</p> <p>Aquatic organisms commonly respond to harsh conditions by forming diapausing stages, which enable populations to survive adverse periods forming egg banks. Production of diapausing eggs is frequently observed in monogonont rotifers, previously changing from asexual to partial sexual reproduction (mixis). In despite that <span class="hlt">zooplankton</span> are frequently used in ecotoxicological assessment because of their sensitivity to various toxicants and their important role in the ecosystems, toxicity evaluations often consider the directly exposed population produced by parthenogenetic reproduction, exclusively. We assessed experimentally effects of exposure to metals on mixis delay and fitness of hatchlings of the rotifer Brachionus plicatilis obtained from a brackish water lagoon with high metal content, especially copper. We show that sub-lethal concentrations of copper affected traits related to sexual reproduction and diapausing egg production in the rotifer. Copper addition did not delay the start of mixis, suggesting that rapid initiation of mixis is promoted in risky environments, according to the hypothesis of mixis as an escape strategy. Higher investment in mixis was obtained when individuals were exposed to metal. Addition of copper negatively affected the hatching success of diapausing eggs and performance of hatchlings. Nevertheless, these effects were greater for individuals formed in non-metal conditions, suggesting an adaptive advantage of populations from natural sediments exposed to copper. These results highlight the ecological and evolutionary consequences of the presence of metals in freshwater environments by modulating diapause adaptive efficacy and the selective process in egg banks.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26490249','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26490249"><span>Characterization of intermittency in <span class="hlt">zooplankton</span> behaviour in turbulence.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Michalec, François-Gaël; Schmitt, François G; Souissi, Sami; Holzner, Markus</p> <p>2015-10-01</p> <p>We consider Lagrangian velocity differences of zooplankters swimming in still water and in turbulence. Using cumulants, we quantify the intermittency properties of their motion recorded using three-dimensional particle tracking velocimetry. Copepods swimming in still water display an intermittent behaviour characterized by a high probability of small velocity increments, and by stretched exponential tails. Low values arise from their steady cruising behaviour while heavy tails result from frequent relocation jumps. In turbulence, we show that at short time scales, the intermittency signature of active copepods clearly differs from that of the underlying flow, and reflects the frequent relocation jumps displayed by these small animals. Despite these differences, we show that copepods swimming in still and turbulent flow belong to the same intermittency class that can be modelled by a log-stable model with non-analytical cumulant generating function. Intermittency in swimming behaviour and relocation jumps may enable copepods to display oriented, collective motion under strong hydrodynamic conditions and thus, may contribute to the formation of <span class="hlt">zooplankton</span> patches in energetic environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4033230','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4033230"><span>Parasitic chytrids sustain <span class="hlt">zooplankton</span> growth during inedible algal bloom</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rasconi, Serena; Grami, Boutheina; Niquil, Nathalie; Jobard, Marlène; Sime-Ngando, Télesphore</p> <p>2014-01-01</p> <p>This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of “inedible” algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19–20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the <span class="hlt">zooplankton</span> diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin. PMID:24904543</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23504921','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23504921"><span>Regional <span class="hlt">zooplankton</span> dispersal provides spatial insurance for ecosystem function.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Symons, Celia C; Arnott, Shelley E</p> <p>2013-05-01</p> <p>Changing environmental conditions are affecting diversity and ecosystem function globally. Theory suggests that dispersal from a regional species pool may buffer against changes in local community diversity and ecosystem function after a disturbance through the establishment of functionally redundant tolerant species. The spatial insurance provided by dispersal may decrease through time after environmental change as the local community monopolizes resources and reduces community invasibility. To test for evidence of the spatial insurance hypothesis and to determine the role dispersal timing plays in this response we conducted a field experiment using crustacean <span class="hlt">zooplankton</span> communities in a subarctic region that is expected to be highly impacted by climate change - Churchill, Canada. Three experiments were conducted where nutrients, salt, and dispersal were manipulated. The three experiments differed in time-since-disturbance that the dispersers were added. We found that coarse measures of diversity (i.e. species richness, evenness, and Shannon-Weiner diversity) were generally resistant to large magnitude disturbances, and that dispersal had the most impact on diversity when dispersers were added shortly after disturbance. Ecosystem functioning (chl-a) was degraded in disturbed communities, but dispersal recovered ecosystem function to undisturbed levels. This spatial insurance for ecosystem function was mediated through changes in community composition and the relative abundance of functional groups. Results suggest that regional diversity and habitat connectivity will be important in the future to maintain ecosystem function by introducing functionally redundant species to promote compensatory dynamics. © 2012 Blackwell Publishing Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ECSS..180..242K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ECSS..180..242K"><span><span class="hlt">Zooplankton</span> responses to increasing sea surface temperatures in the southeastern Australia global marine hotspot</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelly, Paige; Clementson, Lesley; Davies, Claire; Corney, Stuart; Swadling, Kerrie</p> <p>2016-10-01</p> <p>Southeastern Australia is a 'hotspot' for oceanographic change. Here, rapidly increasing sea surface temperatures, rising at more than double the global trend, are largely associated with a southerly extension of the East Australian Current (EAC) and its eddy field. Maria Island, situated at the southern end of the EAC extension at 42°S, 148°E, has been used as a site to study temperature-driven biological trends in this region of accelerated change. <span class="hlt">Zooplankton</span> have short life cycles (usually < 1 year) and are highly sensitive to environmental change, making them an ideal indicator of the biological effects of an increased southward flow of the EAC. Data from in-situ net drops and the Continuous Plankton Recorder (CPR), collected since 2009, together with historical <span class="hlt">zooplankton</span> abundance data, have been analysed in this study. Like the North Atlantic, <span class="hlt">zooplankton</span> communities of southeastern Australia are responding to increased temperatures through relocation, long-term increases in warm-water species and a shift towards a <span class="hlt">zooplankton</span> community dominated by small copepods. The biological trends present evidence of extended EAC influence at Maria Island into autumn and winter months, which has allowed for the rapid establishment of warm-water species during these seasons, and has increased the similarity between Maria Island and the more northerly Port Hacking <span class="hlt">zooplankton</span> community. Generalised Linear Models (GLM) suggest the high salinity and low nutrient properties of EAC-water to be the primary drivers of increasing abundances of warm-water species off southeastern Australia. Changes in both the species composition and size distribution of the Maria Island <span class="hlt">zooplankton</span> community will have effects for pelagic fisheries. This study provides an indication of how <span class="hlt">zooplankton</span> communities influenced by intensifying Western Boundary currents may respond to rapid environmental change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25176489','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25176489"><span>The use of chlorine dioxide for the inactivation of copepod <span class="hlt">zooplankton</span> in drinking water treatment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lin, Tao; Chen, Wei; Cai, Bo</p> <p>2014-01-01</p> <p>The presence of <span class="hlt">zooplankton</span> in drinking water treatment system may cause a negative effect on the aesthetic value of drinking water and may also increase the threat to human health due to they being the carriers of bacteria. Very little research has been done on the effects of copepod inactivation and the mechanisms involved in this process. In a series of bench-scale experiments we used a response surface method to assess the sensitivity of copepod to inactivation when chlorine dioxide (ClO₂) was used as a disinfectant. We also assessed the effects of the ClO₂dosage, exposure time, organic matter concentration and temperature. Results indicated that the inactivation <span class="hlt">rate</span> improved with increasing dosage, exposure time and temperature, whereas it decreased with increasing organic matter concentration. Copepod inactivation was more sensitive to the ClO₂dose than that to the exposure time, while being maintained at the same Ct-value conditions. The activation energy at different temperatures revealed that the inactivation of copepods with ClO₂was temperature-dependent. The presence of organic matter resulted in a lower available dose as well as a shorter available exposure time, which resulted in a decrease in inactivation efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21148422','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21148422"><span>North Atlantic summers have warmed more than winters since 1353, and the response of marine <span class="hlt">zooplankton</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kamenos, Nicholas A</p> <p>2010-12-28</p> <p>Modeling and measurements show that Atlantic marine temperatures are rising; however, the low temporal resolution of models and restricted spatial resolution of measurements (i) mask regional details critical for determining the <span class="hlt">rate</span> and extent of climate variability, and (ii) prevent robust determination of climatic impacts on marine ecosystems. To address both issues for the North East Atlantic, a fortnightly resolution marine climate record from 1353-2006 was constructed for shallow inshore waters and compared to changes in marine <span class="hlt">zooplankton</span> abundance. For the first time summer marine temperatures are shown to have increased nearly twice as much as winter temperatures since 1353. Additional climatic instability began in 1700 characterized by ∼5-65 year climate oscillations that appear to be a recent phenomenon. Enhanced summer-specific warming reduced the abundance of the copepod Calanus finmarchicus, a key food item of cod, and led to significantly lower projected abundances by 2040 than at present. The faster increase of summer marine temperatures has implications for climate projections and affects abundance, and thus biomass, near the base of the marine food web with potentially significant feedback effects for marine food security.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23025072','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23025072"><span>Demography of <span class="hlt">zooplankton</span> (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa) fed Chlorella vulgaris and Scenedesmus acutus cultured on different media.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Morales-Ventura, Jesús; Nandini, S; Sarma, S S S; Castellanos-Páez, Maria Elena</p> <p>2012-09-01</p> <p>Generally <span class="hlt">zooplankton</span> growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of <span class="hlt">zooplankton</span> when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold's basal) medium or the commercial liquid fertilizer (Bayfolan). Experiments were conducted at one algal concentration 1.0 x 10(6) cells/mL of C. vulgaris or its equivalent dry weight of 0.5 x 10(6) cells/mL of S. acutus. The population dynamics were tested at 23 +/- 1 degrees C in 100 mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 <span class="hlt">zooplankton</span> 2 algal species x 2 culture media x 4 replicates). For the life table experiments with M. macrocopa, we introduced 10 neonates (<24h old) into each test jar containing the specific algal type and concentration. For the rotifer experiments, we set 5mL tubes with one neonate each and 10 replicates for each algal species and culture medium. We found that the average rotifer life span was not influenced by the diet, but for M. macrocopa fed S. acutus cultured in Bold's medium, the average lifespan was significantly lower than with the other diets. The gross and net reproductive <span class="hlt">rates</span> of A. fissa (ranging from 18-36 offspring per female) were significantly higher for C vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive <span class="hlt">rates</span> for B. rubens than S. acutus diets. The reproductive <span class="hlt">rates</span> of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase <span class="hlt">rate</span>, derived from growth experiments of A. fissa and B. rubens</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5563156','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5563156"><span>Changes in <span class="hlt">zooplankton</span> community, and seston and <span class="hlt">zooplankton</span> fatty acid profiles at the freshwater/saltwater interface of the Chowan River, North Carolina</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rinchard, Jacques; Kimmel, David G.</p> <p>2017-01-01</p> <p>The variability in <span class="hlt">zooplankton</span> fatty acid composition may be an indicator of larval fish habitat quality as fatty acids are linked to fish larval growth and survival. We sampled an anadromous fish nursery, the Chowan River, during spring of 2013 in order to determine how the seston fatty acid composition varied in comparison with the <span class="hlt">zooplankton</span> community composition and fatty acid composition during the period of anadromous larval fish residency. The seston fatty acid profiles showed no distinct pattern in relation to sampling time or location. The mesozooplankton community composition varied spatially and the fatty acid profiles were typical of freshwater species in April. The Chowan River experienced a saltwater intrusion event during May, which resulted in brackish water species dominating the <span class="hlt">zooplankton</span> community and the fatty acid profile showed an increase in polyunsaturated fatty acids (PUFA), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The saltwater intrusion event was followed by an influx of freshwater due to high precipitation levels in June. The <span class="hlt">zooplankton</span> community composition once again became dominated by freshwater species and the fatty acid profiles shifted to reflect this change; however, EPA levels remained high, particularly in the lower river. We found correlations between the seston, microzooplankton and mesozooplankton fatty acid compositions. Salinity was the main factor correlated to the observed pattern in species composition, and fatty acid changes in the mesozooplankton. These data suggest that anadromous fish nursery habitat likely experiences considerable spatial variability in fatty acid profiles of <span class="hlt">zooplankton</span> prey and that are correlated to seston community composition and hydrodynamic changes. Our results also suggest that sufficient prey density as well as a diverse fatty acid composition is present in the Chowan River to support larval fish production. PMID:28828262</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=260875','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=260875"><span>Estimating influence of stocking regimes on livestock <span class="hlt">grazing</span> distributions</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Ungulates often concentrate <span class="hlt">grazing</span> at small hotspots in the larger landscape, and dispersing livestock away from these intensively <span class="hlt">grazed</span> areas is one of the central challenges in range management. We evaluated a technique based on shifting the stocking date to prevent overgrazing of small areas co...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=345216','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=345216"><span>Targeted livestock <span class="hlt">grazing</span> to improve and restore rangelands</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Targeted <span class="hlt">grazing</span> is the application of a specific kind of livestock at the appropriate season, duration, and intensity to accomplish defined vegetation or landscape goals. <span class="hlt">Grazing</span> by wild and domestic animals is a powerful natural force working in all ecosystems. The ability of selective herbivory t...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=302161','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=302161"><span>Cattle <span class="hlt">grazing</span> and vegetation succession on burned sagebrush steppe</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>There is limited information on the effects of cattle <span class="hlt">grazing</span> to longer-term plant community composition and productivity following fire in big sagebrush steppe. This study evaluated vegetation response to cattle <span class="hlt">grazing</span> over seven years (2007-2013) on burned Wyoming big sagebrush (Artemisia triden...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-12-23/pdf/2011-32965.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-12-23/pdf/2011-32965.pdf"><span>76 FR 80329 - Information Collection; <span class="hlt">Grazing</span> Permit Administration Forms</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-12-23</p> <p>... to another account Information on the allotment; number of cattle, horses, or sheep; Period range not... DEPARTMENT OF AGRICULTURE Forest Service Information Collection; <span class="hlt">Grazing</span> Permit Administration... organizations on the extension with no revision of a currently approved information collection, <span class="hlt">Grazing</span> Permit...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=318306','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=318306"><span>Economic viability of beef cattle <span class="hlt">grazing</span> systems under prolonged drought</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Prolonged drought in the Southern Great Plains of the USA in recent years has raised concerns about vulnerability of beef cattle <span class="hlt">grazing</span> systems under adverse climate change. To help address the economic viability of beef <span class="hlt">grazing</span> operations in the Southern Great Plains, this paper provides an econom...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H23B1642M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H23B1642M"><span>Livestock <span class="hlt">Grazing</span> as a Driver of Vernal Pool Ecohydrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Michaels, J.; McCarten, N. F.</p> <p>2017-12-01</p> <p>Vernal pools are seasonal wetlands that host rare plant communities of high conservation priority. Plant community composition is largely driven by pool hydroperiod. A previous study found that vernal pools <span class="hlt">grazed</span> by livestock had longer hydroperiods compared with pools excluded from <span class="hlt">grazing</span> for 10 years, and suggests that livestock <span class="hlt">grazing</span> can be used to protect plant diversity. It is important to assess whether observed differences are due to the <span class="hlt">grazing</span> or due to water balance variables including upland discharge into or out of the pools since no a priori measurements were made of the hydrology prior to <span class="hlt">grazing</span>. To address this question, in 2016 we compared 15 pools that have been <span class="hlt">grazed</span> continuously and 15 pools that have been fenced off for over 40 years at a site in Sacramento County. We paired pools based on abiotic characteristics (size, shape, slope, soil type) to minimize natural variation. We sampled vegetation and water depth using Solinst level loggers. We found that plant diversity and average hydroperiod was significantly higher in the <span class="hlt">grazed</span> pools. We are currently measuring groundwater connectivity and upland inputs in order to compare the relative strength of livestock <span class="hlt">grazing</span> as a driver of hydroperiod to these other drivers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA605677','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA605677"><span>Environmental Assessment of Beale AFB <span class="hlt">Grazing</span> Lease Program</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2012-12-01</p> <p>Beale AFB will use livestock (cattle, sheep and goats ) on its properties throughout the year as needed for the control of noxious weeds, reduction...initiating a wildfire. California Farm Bureau Federation policy recognizes that <span class="hlt">grazing</span> is the most practical and environmentally acceptable way to...Site Monitoring Well Installation and Annual Targeted Goat <span class="hlt">Grazing</span> Project, Placer County, California. 21 September 2011.  </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037073','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037073"><span>Using packrat middens to assess <span class="hlt">grazing</span> effects on vegetation change</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fisher, J.; Cole, K.L.; Anderson, R. Scott</p> <p>2009-01-01</p> <p>Research on <span class="hlt">grazing</span> effects usually compares the same sites through time or <span class="hlt">grazed</span> and ungrazed sites over the same time period. Both approaches are complicated in arid environments where <span class="hlt">grazing</span> can have a long undocumented history and landscapes can be spatially heterogenous. This work employs both approaches simultaneously by comparing <span class="hlt">grazed</span> and ungrazed samples through both time and space using fossil plant macrofossils and pollen from packrat middens. A series of 27 middens, spanning from 995 yr BP to the present, were collected from Glen Canyon in southeastern Utah, USA. These middens detail vegetation change just prior to, and following, the historical introduction of domesticated grazers and also compares assemblages from nearby ungrazable mesas. Pre-<span class="hlt">grazing</span> middens, and modern middens from ungrazed areas, record more native grasses, native herbs, and native shrubs such as Rhus trilobata, Amelanchier utahensis, and Shepherdia rotundifolia than modern middens from <span class="hlt">grazed</span> areas. Ordinations demonstrate that site-to-site variability is more important than any temporal changes, making selection of comparable <span class="hlt">grazed</span> versus ungrazed study treatments difficult. But within similar sites, the changes through time show that <span class="hlt">grazing</span> lowered the number of taxa recorded, and lessened the pre-existing site differences, homogenizing the resultant plant associations in this desert grassland.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=324231','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=324231"><span>From the lab bench: A systematic approach to <span class="hlt">grazing</span> cattle</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>A column was written to discuss the use of <span class="hlt">grazing</span> systems to overcome challenges of managing <span class="hlt">grazed</span> pastures. Kentucky cattlemen must manage around summer slumps in growth of cool-season perennial grasses, periodic drought, and cattle markets that do not always cooperate with pasture growth patter...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=304249','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=304249"><span>Dairy farmers using mob <span class="hlt">grazing</span> in Pennsylvania and New York</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Proponents of ultra-high stocking density <span class="hlt">grazing</span> emphasize increased forage use efficiency and soil improvement by <span class="hlt">grazing</span> mature forage with stocking densities up to 500,000 lb per acre of beef cattle on small paddocks with rest periods up to 180 days. However, it is unclear if this management tec...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=302629','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=302629"><span>A look at dairy mob <span class="hlt">grazing</span> in the Northeast</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Proponents of ultra-high stocking density (UHSD) <span class="hlt">grazing</span> emphasize increased forage use efficiency and soil improvement by <span class="hlt">grazing</span> mature forage with stocking densities up to 560,425 kg/ha of beef cattle on small paddocks with rest periods up to 125 days. However, it is unclear if this management te...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=336416','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=336416"><span>Choosing cover crops for a fall <span class="hlt">grazing</span> season</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Forage brassicas are annuals that can be utilized as pasture during the spring, summer, and fall <span class="hlt">grazing</span> seasons. They are quick maturing and can be <span class="hlt">grazed</span> 60 to 120 days after planting. A 2-year study at the USDA-ARS PSWMRU showed that yield and total digestible nutrients of three brassica varietie...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/27839','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/27839"><span>Consequences of ignoring geologic variation in evaluating <span class="hlt">grazing</span> impacts</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Jonathan W. Long; Alvin L. Medina</p> <p>2006-01-01</p> <p>The geologic diversity of landforms in the Southwest complicates efforts to evaluate impacts of land uses such as livestock <span class="hlt">grazing</span>. We examined a research study that evaluated relationships between trout biomass and stream habitat in the White Mountains of east-central Arizona. That study interpreted results of stepwise regressions and a nonparametric test of “<span class="hlt">grazed</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B21H0168S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B21H0168S"><span>Climatic and <span class="hlt">Grazing</span> Controls on Biological Soil Crust Nitrogen Fixation in Semi-arid Ecosystems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwabedissen, S. G.; Reed, S.; Lohse, K. A.; Magnuson, T. S.</p> <p>2014-12-01</p> <p>Nitrogen, next to water, is believed to be the main limiting resource in arid and semi-arid ecosystems. Biological soil crusts (biocrusts) -a surface community of mosses, lichens and cyanobacteria-have been found to be the main influx of "new" nitrogen (N) into many dryland ecosystems. Controls on biocrust N fixation <span class="hlt">rates</span> include climate (temperature and moisture), phosphorus availability, and disturbance factors such as trampling, yet a systematic examination of climatic and disturbance controls on biocrusts communities is lacking. Biocrust samples were collected along an elevation gradient in the Reynolds Creek Experimental Watershed near Murphy, Idaho. Four sites were selected from a sagebrush steppe ecosystem with precipitation ranging from ≤250mm/yr to ≥1100mm/yr. Each site included 5 <span class="hlt">grazed</span> plots and one historic exclosure plot that has been free from <span class="hlt">grazing</span> for more than 40 years. Five samples each were collected from under plants and from interplant spaces from the <span class="hlt">grazed</span> plots and exclosures and analyzed for potential N fixation using an acetylene reduction assay. We hypothesized that N fixation <span class="hlt">rates</span> would be the highest in the exclosures of the two middle sites along the elevation gradient, due to the lack of disturbance and optimal temperature and moisture, respectively. As predicted, results showed higher <span class="hlt">rates</span> of potential N fixation in exclosures than non-exclosures at a mid-elevation 8.4 ± 3.1 kg N/ha/yr in the exclosures compared to 1.8 ± 1.5 kg N/ha/yr indicating that <span class="hlt">grazing</span> may reduce N fixation activity. Interestingly, <span class="hlt">rates</span> were 2-5 times lower under plant canopies compared to interplant spaces at all but the highest elevation site. Findings from our study suggest that biocrust N fixation may be a dominant input of N into theses dryland systems and, in line with our hypotheses, that climate, location within the landscape, and disturbance may interact to regulate the <span class="hlt">rates</span> of this fundamental ecosystem process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B13I0631R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B13I0631R"><span>Incorporating <span class="hlt">grazing</span> into an eco-hydrologic model: Simulating coupled human and natural systems in rangelands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reyes, J. J.; Liu, M.; Tague, C.; Choate, J. S.; Evans, R. D.; Johnson, K. A.; Adam, J. C.</p> <p>2013-12-01</p> <p> the daily-to-yearly ratio of net primary productivity allocation of carbon, non-structural carbohydrate pool, <span class="hlt">rate</span> of root turnover, and leaf on/off days. We also ran RHESSys over AmeriFlux sites representing a spectrum of rangeland ecosystems, such as at Konza Prairie (Kansas), Fort Peck (Montana), and Corral Pocket (Utah), as well as <span class="hlt">grazed</span> versus ungrazed sites. We evaluated RHESSys using net ecosystem exchange . Competition between rangeland vegetation types with different physiological parameters, such as carbon:nitrogen ratio and specific leaf area within a single site were also tested. Preliminary results indicated both species-specific parameters and allocation controls were important to capturing the ecosystem response to environmental conditions. Furthermore, the addition of a <span class="hlt">grazing</span> component allowed us to better capture impacts of management at <span class="hlt">grazed</span> sites. Future research will involve incorporation of other <span class="hlt">grazing</span> processes, such as impacts of excreta and increased nutrient availability and cycling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29110238','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29110238"><span>Herbage intake of dairy cows in mixed sequential <span class="hlt">grazing</span> with breeding ewes as followers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiménez-Rosales, Juan Daniel; Améndola-Massiotti, Ricardo Daniel; Burgueño-Ferreira, Juan Andrés; Ramírez-Valverde, Rodolfo; Topete-Pelayo, Pedro; Huerta-Bravo, Maximino</p> <p>2018-03-01</p> <p>This study aimed to evaluate the hypothesis that mixed sequential <span class="hlt">grazing</span> of dairy cows and breeding ewes is beneficial. During the seasons of spring-summer 2013 and autumn-winter 2013-2014, 12 (spring-summer) and 16 (autumn-winter) Holstein Friesian cows and 24 gestating (spring-summer) and lactating (autumn-winter) Pelibuey ewes <span class="hlt">grazed</span> on six (spring-summer) and nine (autumn-winter) paddocks of alfalfa and orchard grass mixed pastures. The treatments "single species cow <span class="hlt">grazing</span>" (CowG) and "mixed sequential <span class="hlt">grazing</span> with ewes as followers of cows" (MixG) were evaluated, under a completely randomized design with two replicates per paddock. Herbage mass on offer (HO) and residual herbage mass (RH) were estimated by cutting samples. The estimate of herbage intake (HI) of cows was based on the use of internal and external markers; the apparent HI of ewes was calculated as the difference between HO (RH of cows) and RH. Even though HO was higher in CowG, the HI of cows was higher in MixG during spring-summer and similar in both treatments during autumn-winter, implying that in MixG the effects on the cows HI of higher alfalfa proportion and herbage accumulation <span class="hlt">rate</span> evolving from lower residual herbage mass in the previous cycle counteracted that of a higher HO in CowG. The HI of ewes was sufficient to enable satisfactory performance as breeding ewes. Thus, the benefits of mixed sequential <span class="hlt">grazing</span> arose from higher herbage accumulation, positive changes in botanical composition, and the achievement of sheep production without negative effects on the herbage intake of cows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70020187','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70020187"><span>Demographic patterns of Ferocactus cylindraceus in relation to substrate age and <span class="hlt">grazing</span> history</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bowers, Janice E.</p> <p>1997-01-01</p> <p>Three subpopulations of Ferocactus cylindraceus, a short-columnar cactus of the Sonoran and Mojave deserts, were sampled in Grand Canyon, Arizona, USA, at sites representing a range of substrate ages and different <span class="hlt">grazing</span> histories. Age-height relations were determined from annual growth, then used to estimate probable year of establishment for each cohort. Eight years between 1944 and 1992 were especially favorable for establishment. Six of these 8 years coincided with El Nino-Southern Oscillation conditions, indicating that as for many woody plants in arid regions, somewhat unusual climatic conditions are necessary if populations are to replace themselves. Comparison of age structures showed that established and developing populations have somewhat different dynamics in that the <span class="hlt">rate</span> of population increase was slowest on the youngest terrace. On the ancient terraces, about half the plants were less than 25 years old. Plants older than 40 years were few; however the oldest plants in the study (about 49 years) grew on the ancient terraces. On the recent terrace, 76% of the subpopulation was 25 years or younger, and the oldest living plant was about 36 years of age. The age structures of subpopulations on <span class="hlt">grazed</span> and ungrazed sites also differed markedly. On ungrazed sites, subpopulations were more or less at equilibrium, with enough young plants to replace old ones as they died. In contrast, the subpopulation on the <span class="hlt">grazed</span> site was in a state of marked disequilibrium. <span class="hlt">Grazing</span> before 1981 largely extirpated a palatable subshrub that was probably an important nurse plant. Until the shrub population at Indian Canyon recovers from decades of burro <span class="hlt">grazing</span>, a rebound in E cylindraceus establishment is not to be expected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B23C0624H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B23C0624H"><span>Investigating the Effect of Livestock <span class="hlt">Grazing</span> and Associated Plant Community Shifts on Carbon and Nutrient Cycling in Alberta, Canada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hewins, D. B.; Chuan, S.; Stolnikova, E.; Bork, E. W.; Carlyle, C. N.; Chang, S. X.</p> <p>2015-12-01</p> <p>Grassland ecosystems are ubiquitous across the globe covering an estimated 40 % of Earth's terrestrial landmass. These ecosystems are widely valued for providing forage for domestic livestock and a suite of important ecosystem goods and services including carbon (C) storage. Despite storing more than 30 % of soil C globally, the effect of both livestock <span class="hlt">grazing</span> and the associated change in plant community structure in response to <span class="hlt">grazing</span> on C and nutrient cycling remains uncertain. To gain a quantitative understanding of the direct and indirect effects of livestock <span class="hlt">grazing</span> on C and nutrient cycling, we established study sites at 15 existing site localities with paired long-term <span class="hlt">grazing</span> (ca. 30 y) and non-<span class="hlt">grazed</span> treatments (totaling 30 unique plant communities). Our sites were distributed widely across Alberta in three distinct grassland bioclimatic zones allowing us to make comparisons across the broad range of climate variability typical of western Canadian grasslands. In each plant community we decomposed 5 common plant species that are known to increase or decrease in response to <span class="hlt">grazing</span> pressure, a unique plant community sample, and a cellulose paper control. We measured mass loss, initial lignin, C and N concentrations at 0, 1, 3, 6 and 12 months of field incubation. In addition we assayed hydrolytic and oxidative extracellular enzymes associated with for C (n= 5 hydrolytic; phenoloxidase and peroxidase) and nutrients (i.e. N and P; n=1 ea.) cycling from each litter sample at each collection. Our results suggest that by changing the plant community structure, <span class="hlt">grazing</span> can affect <span class="hlt">rates</span> of decomposition and associated biogeochemical cycling by changing plant species and associated litter inputs. Moreover, measures of microbial function are controlled by site-specific conditions (e.g. temperature and precipitation), litter chemistry over the course of our incubation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980EnMan...4..165P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980EnMan...4..165P"><span>Simulated <span class="hlt">grazing</span> responses on the proposed prairies National Park</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parton, William J.; Wright, R. Gerald; Risser, Paul G.</p> <p>1980-03-01</p> <p>The tallgrass prairie version of the ELM Grassland Model was used to evaluate the potential impact of establishing a tallgrass prairie National Park in the Flint Hills region of Kansas. This total ecosystem model simulates ( a) the flow of water, heat, nitrogen, and phosphorus through the ecosystem and( b) the biomass dynamics of plants and consumers. It was specifically developed to study the effects of levels and types of herbivory, climatic variation, and fertilization upon grassland ecosystems. The model was used to simulate the impact of building up herds of bison, elk, antelope, and wolves on a tallgrass prairie. The results show that the <span class="hlt">grazing</span> levels in the park should not be decreased below the prepark <span class="hlt">grazing</span> levels (moderate <span class="hlt">grazing</span> with cattle) and that the final <span class="hlt">grazing</span> levels in the park could be maintained at a slightly higher level than the prepark <span class="hlt">grazing</span> levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28307401','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28307401"><span>Top-down impact through a bottom-up mechanism: the effect of limpet <span class="hlt">grazing</span> on growth, productivity and carbon allocation of Zostera marina L. (eelgrass).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zimmerman, Richard C; Kohrs, Donald G; Alberte, Randall S</p> <p>1996-09-01</p> <p>The unusual appearance of a commensal eelgrass limpet [Tectura depicta (Berry)] from southern California at high density (up to 10 shoot -1 ) has coincided with the catastrophic decline of a subtidal Zostera marina L. meadow in Monterey Bay, California. Some commensal limpets <span class="hlt">graze</span> the chloroplast-rich epidermis of eelgrass leaves, but were not known to affect seagrass growth or productivity. We evaluated the effect on eelgrass productivity of <span class="hlt">grazing</span> by limpets maintained at natural densities (8±2 shoot -1 ) in a natural light mesocosm for 45 days. Growth <span class="hlt">rates</span>, carbon reserves, root proliferation and net photosynthesis of <span class="hlt">grazed</span> plants were 50-80% below those of ungrazed plants, but biomass-specific respiration was unaffected. The daily period of irradiance-saturated photosynthesis (H sat ) needed to maintain positive carbon balance in <span class="hlt">grazed</span> plants approached 13.5 h, compared with 5-6 h for ungrazed plants. The amount of carbon allocated to roots of ungrazed plants was 800% higher than for <span class="hlt">grazed</span> plants. By <span class="hlt">grazing</span> the chlorophyll-rich epidermis, T. depicta induced carbon limitation in eelgrass growing in an other-wise light-replete environment. Continued northward movement of T. depicta, may have significant impacts on eelgrass production and population dynamics in the northeast Pacific, even thought this limpet consumes very little plant biomass. This interaction is a dramatic example of top-down control (<span class="hlt">grazing</span>/predation) of eelgrass productivity and survival operating via a bottom-up mechanism (photosynthesis limitation).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15063074','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15063074"><span>Some ecological implications of a neem (azadirachtin) insecticide disturbance to <span class="hlt">zooplankton</span> communities in forest pond enclosures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kreutzweiser, David P; Sutton, Trent M; Back, Richard C; Pangle, Kevin L; Thompson, Dean G</p> <p>2004-04-28</p> <p>A neem-based insecticide, Neemix 4.5, was applied to forest pond enclosures at concentrations of 10, 17, and 28 microg l(-1) azadirachtin (the active ingredient). At these test concentrations, significant, concentration-dependent reductions in numbers of adult copepods were observed, but immature copepod and cladoceran populations were unaffected. There was no evidence of recovery of adult copepods within the sampling season (May to October). The ecological significance of this disturbance to the <span class="hlt">zooplankton</span> community was examined by determining biomass as a measure of food availability for higher predators, plankton community respiration, dissolved oxygen (DO) concentrations, and conductivity as functional indicators of ecosystem stress, and <span class="hlt">zooplankton</span> food web stability as a measure of effects on trophic structure. The selective removal or reduction of adult copepods was sufficient to measurably reduce total <span class="hlt">zooplankton</span> biomass for several weeks mid-season. During the period of maximal impact (about 4-9 weeks after the applications), total plankton community respiration was significantly reduced, and this appeared to contribute to significant, concentration-dependent increases in dissolved oxygen and decreases in conductivity among treated enclosures. The reductions in adult copepods resulted in negative effects on <span class="hlt">zooplankton</span> food web stability through eliminations of a trophic link and reduced interactions and connectance. Comparing the results here to those from a previous study with tebufenozide, which was selectively toxic to cladocerans and had little effect on food web stability, indicates that differential sensitivity among taxa can influence the ecological significance of pesticide effects on <span class="hlt">zooplankton</span> communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatCC...6.1124S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatCC...6.1124S"><span>Ocean acidification reduces demersal <span class="hlt">zooplankton</span> that reside in tropical coral reefs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Joy N.; de'Ath, Glenn; Richter, Claudio; Cornils, Astrid; Hall-Spencer, Jason M.; Fabricius, Katharina E.</p> <p>2016-12-01</p> <p>The in situ effects of ocean acidification on <span class="hlt">zooplankton</span> communities remain largely unexplored. Using natural volcanic CO2 seep sites around tropical coral communities, we show a threefold reduction in the biomass of demersal <span class="hlt">zooplankton</span> in high-CO2 sites compared with sites with ambient CO2. Differences were consistent across two reefs and three expeditions. Abundances were reduced in most taxonomic groups. There were no regime shifts in <span class="hlt">zooplankton</span> community composition and no differences in fatty acid composition between CO2 levels, suggesting that ocean acidification affects the food quantity but not the quality for nocturnal plankton feeders. Emergence trap data show that the observed reduction in demersal plankton may be partly attributable to altered habitat. Ocean acidification changes coral community composition from branching to massive bouldering coral species, and our data suggest that bouldering corals represent inferior daytime shelter for demersal <span class="hlt">zooplankton</span>. Since <span class="hlt">zooplankton</span> represent a major source of nutrients for corals, fish and other planktivores, this ecological feedback may represent an additional mechanism of how coral reefs will be affected by ocean acidification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18470380','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18470380"><span>Water quality and <span class="hlt">zooplankton</span> in tanks with larvae of Brycon Orbignyanus (Valenciennes, 1949).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sipaúba-Tavares, L H; Alvarez, E J da S; Braga, F M de S</p> <p>2008-02-01</p> <p>Due to the importance of water variables conditions and available food in the development and survival of fish larvae, the current research evaluates the effects of two different food treatments (ration + <span class="hlt">zooplankton</span> and only <span class="hlt">zooplankton</span>) and water quality in tanks with Brycon orbignyanus larvae. Total water transparency (45 cm) has been mainly associated with short residence time, continuous water flow and shallowness. Dissolved oxygen ranged between 1.32 and 7.00 mg.L(-1) in tanks with ration + <span class="hlt">zooplankton</span> and between 1.82 and 7.60 mg.L(-1) in tanks with only <span class="hlt">zooplankton</span> treatments. Nutrients were directly affected by the addition of ration in water, with the exception of nitrite. Ten Rotifera species were found represented by high densities, ranging between 8.7 x 10(5) and 1.3 x 10(6) org.m(-3), throughout the experimental period (January to March/1996). Cladocera had the lowest density in the four tanks under analysis and ranged between 4.7 x 10(4) and 2.1 x 10(5) org.m(-3) for the six species. Diaphanosoma birgei has been classified as the most frequent species. Since ration + <span class="hlt">zooplankton</span> produced better larvae yield, this treatment is recommended for Brycon orbignyanus larvae.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DSRII..98...63C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DSRII..98...63C"><span>Variability of <span class="hlt">zooplankton</span> communities at Condor seamount and surrounding areas, Azores (NE Atlantic)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carmo, Vanda; Santos, Mariana; Menezes, Gui M.; Loureiro, Clara M.; Lambardi, Paolo; Martins, Ana</p> <p>2013-12-01</p> <p>Seamounts are common topographic features around the Azores archipelago (NE Atlantic). Recently there has been increasing research effort devoted to the ecology of these ecosystems. In the Azores, the mesozooplankon is poorly studied, particularly in relation to these seafloor elevations. In this study, <span class="hlt">zooplankton</span> communities in the Condor seamount area (Azores) were investigated during March, July and September 2010. Samples were taken during both day and night with a Bongo net of 200 µm mesh that towed obliquely within the first 100 m of the water column. Total abundance, biomass and chlorophyll a concentrations did not vary with sampling site or within the diel cycle but significant seasonal variation was observed. Moreover, <span class="hlt">zooplankton</span> community composition showed the same strong seasonal pattern regardless of spatial or daily variability. Despite seasonal differences, the <span class="hlt">zooplankton</span> community structure remained similar for the duration of this study. Seasonal variability better explained our results than mesoscale spatial variability. Spatial homogeneity is probably related with island proximity and local dynamics over Condor seamount. <span class="hlt">Zooplankton</span> literature for the region is sparse, therefore a short review of the most important <span class="hlt">zooplankton</span> studies from the Azores is also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3923862','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3923862"><span>Mixed <span class="hlt">Grazing</span> Systems Benefit both Upland Biodiversity and Livestock Production</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fraser, Mariecia D.; Moorby, Jon M.; Vale, James E.; Evans, Darren M.</p> <p>2014-01-01</p> <p>Background With world food demand expected to double by 2050, identifying farming systems that benefit both agricultural production and biodiversity is a fundamentally important challenge for the 21st century, but this has to be achieved in a sustainable way. Livestock <span class="hlt">grazing</span> management directly influences both economic outputs and biodiversity on upland farms while contributing to potentially damaging greenhouse gas emissions, yet no study has attempted to address these impacts simultaneously. Methods Using a replicated, landscape-scale field experiment consisting of five management ‘systems’ we tested the effects of progressively altering elements within an upland farming system, viz i) incorporating cattle <span class="hlt">grazing</span> into an upland sheep system, ii) integrating <span class="hlt">grazing</span> of semi-natural rough <span class="hlt">grazing</span> into a mixed <span class="hlt">grazing</span> system based on improved pasture, iii) altering the stocking ratio within a mixed <span class="hlt">grazing</span> system, and iv) replacing modern crossbred cattle with a traditional breed. We quantified the impacts on livestock productivity and numbers of birds and butterflies over four years. Results, Conclusion and Significance We found that management systems incorporating mixed <span class="hlt">grazing</span> with cattle improve livestock productivity and reduce methane emissions relative to sheep only systems. Systems that also included semi-natural rough <span class="hlt">grazing</span> consistently supported more species of birds and butterflies, and it was possible to incorporate bouts of summer <span class="hlt">grazing</span> of these pastures by cattle to meet habitat management prescriptions without compromising cattle performance overall. We found no evidence that the system incorporating a cattle breed popular as a conservation grazer was any better for bird and butterfly species richness than those based on a mainstream breed, yet methane emissions from such a system were predicted to be higher. We have demonstrated that mixed upland <span class="hlt">grazing</span> systems not only improve livestock production, but also benefit biodiversity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24551216','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24551216"><span>Mixed <span class="hlt">grazing</span> systems benefit both upland biodiversity and livestock production.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fraser, Mariecia D; Moorby, Jon M; Vale, James E; Evans, Darren M</p> <p>2014-01-01</p> <p>With world food demand expected to double by 2050, identifying farming systems that benefit both agricultural production and biodiversity is a fundamentally important challenge for the 21(st) century, but this has to be achieved in a sustainable way. Livestock <span class="hlt">grazing</span> management directly influences both economic outputs and biodiversity on upland farms while contributing to potentially damaging greenhouse gas emissions, yet no study has attempted to address these impacts simultaneously. Using a replicated, landscape-scale field experiment consisting of five management 'systems' we tested the effects of progressively altering elements within an upland farming system, viz i) incorporating cattle <span class="hlt">grazing</span> into an upland sheep system, ii) integrating <span class="hlt">grazing</span> of semi-natural rough <span class="hlt">grazing</span> into a mixed <span class="hlt">grazing</span> system based on improved pasture, iii) altering the stocking ratio within a mixed <span class="hlt">grazing</span> system, and iv) replacing modern crossbred cattle with a traditional breed. We quantified the impacts on livestock productivity and numbers of birds and butterflies over four years. We found that management systems incorporating mixed <span class="hlt">grazing</span> with cattle improve livestock productivity and reduce methane emissions relative to sheep only systems. Systems that also included semi-natural rough <span class="hlt">grazing</span> consistently supported more species of birds and butterflies, and it was possible to incorporate bouts of summer <span class="hlt">grazing</span> of these pastures by cattle to meet habitat management prescriptions without compromising cattle performance overall. We found no evidence that the system incorporating a cattle breed popular as a conservation grazer was any better for bird and butterfly species richness than those based on a mainstream breed, yet methane emissions from such a system were predicted to be higher. We have demonstrated that mixed upland <span class="hlt">grazing</span> systems not only improve livestock production, but also benefit biodiversity, suggesting a 'win-win' solution for farmers and conservationists.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=328744','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=328744"><span><span class="hlt">Grazing</span> behavior and production characteristics among cows differing in residual feed intake while <span class="hlt">grazing</span> late season Idaho rangeland</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>The objectives were to determine if cows classified as either low- or high-residual feed intake (LRFI or HRFI) differed in BW, BCS, and winter <span class="hlt">grazing</span> activity over time. Thirty Hereford x Angus (LRFI = 16; HRFI = 14) 2-year-old cows <span class="hlt">grazed</span> sagebrush-steppe for 78 d beginning 29 September 2016. Body...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=236341','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=236341"><span>Sequence <span class="hlt">Grazing</span> of Perennial and Annual Cool-Season Grasses to Extend the <span class="hlt">Grazing</span> Season for Stocker Calves</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p><span class="hlt">Grazing</span> of cool-season grasses by beef calves before entry into the feedlot for finishing is an important component of the US beef production system. The length of time in the feedlot and the quantity of feed grain required to reach market BW would be reduced if more BW was gained during the <span class="hlt">grazing</span>...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=342385','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=342385"><span>A narrower gap of <span class="hlt">grazing</span> intensity. Reply to Fetzel et al. 2017. Seasonality constrains to livestock <span class="hlt">grazing</span> intensity</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Fetzel et al. (2017) globally mapped the gap between observed and potential <span class="hlt">grazing</span> intensity (GI): the ratio between consumption by livestock and ANPP. Fetzel et al. (2017) estimated <span class="hlt">grazing</span> land, forage production and livestock demand at a half-degree resolution. They mapped GI below 15% for most ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5748176','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5748176"><span><span class="hlt">Zooplankton</span> can actively adjust their motility to turbulent flow</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Michalec, François-Gaël; Fouxon, Itzhak</p> <p>2017-01-01</p> <p>Calanoid copepods are among the most abundant metazoans in the ocean and constitute a vital trophic link within marine food webs. They possess relatively narrow swimming capabilities, yet are capable of significant self-locomotion under strong hydrodynamic conditions. Here we provide evidence for an active adaptation that allows these small organisms to adjust their motility in response to background flow. We track simultaneously and in three dimensions the motion of flow tracers and planktonic copepods swimming freely at several intensities of quasi-homogeneous, isotropic turbulence. We show that copepods synchronize the frequency of their relocation jumps with the frequency of small-scale turbulence by performing frequent relocation jumps of low amplitude that seem unrelated to localized hydrodynamic signals. We develop a model of plankton motion in turbulence that shows excellent quantitative agreement with our measurements when turbulence is significant. We find that, compared with passive tracers, active motion enhances the diffusion of organisms at low turbulence intensity whereas it dampens diffusion at higher turbulence levels. The existence of frequent jumps in a motion that is otherwise dominated by turbulent transport allows for the possibility of active locomotion and hence to transition from being passively advected to being capable of controlling diffusion. This behavioral response provides <span class="hlt">zooplankton</span> with the capability to retain the benefits of self-locomotion despite turbulence advection and may help these organisms to actively control their distribution in dynamic environments. Our study reveals an active adaptation that carries strong fitness advantages and provides a realistic model of plankton motion in turbulence. PMID:29229858</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9440326','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9440326"><span>Sound scattering by several <span class="hlt">zooplankton</span> groups. II. Scattering models.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stanton, T K; Chu, D; Wiebe, P H</p> <p>1998-01-01</p> <p>Mathematical scattering models are derived and compared with data from <span class="hlt">zooplankton</span> from several gross anatomical groups--fluidlike, elastic shelled, and gas bearing. The models are based upon the acoustically inferred boundary conditions determined from laboratory backscattering data presented in part I of this series [Stanton et al., J. Acoust. Soc. Am. 103, 225-235 (1998)]. The models use a combination of ray theory, modal-series solution, and distorted wave Born approximation (DWBA). The formulations, which are inherently approximate, are designed to include only the dominant scattering mechanisms as determined from the experiments. The models for the fluidlike animals (euphausiids in this case) ranged from the simplest case involving two rays, which could qualitatively describe the structure of target strength versus frequency for single pings, to the most complex case involving a rough inhomogeneous asymmetrically tapered bent cylinder using the DWBA-based formulation which could predict echo levels over all angles of incidence (including the difficult region of end-on incidence). The model for the elastic shelled body (gastropods in this case) involved development of an analytical model which takes into account irregularities and discontinuities of the shell. The model for gas-bearing animals (siphonophores) is a hybrid model which is composed of the summation of the exact solution to the gas sphere and the approximate DWBA-based formulation for arbitrarily shaped fluidlike bodies. There is also a simplified ray-based model for the siphonophore. The models are applied to data involving single pings, ping-to-ping variability, and echoes averaged over many pings. There is reasonable qualitative agreement between the predictions and single ping data, and reasonable quantitative agreement between the predictions and variability and averages of echo data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934703','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934703"><span>DNA Barcoding of Metazoan <span class="hlt">Zooplankton</span> Copepods from South Korea</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ryu, Shi Hyun; Kim, Sang Ki; Lee, Jin Hee; Lim, Young Jin; Lee, Jimin; Jun, Jumin; Kwak, Myounghai; Lee, Young-Sup; Hwang, Jae-Sam; Venmathi Maran, Balu Alagar; Chang, Cheon Young; Kim, Il-Hoi; Hwang, Ui Wook</p> <p>2016-01-01</p> <p>Copepods, small aquatic crustaceans, are the most abundant metazoan <span class="hlt">zooplankton</span> and outnumber every other group of multicellular animals on earth. In spite of ecological and biological importance in aquatic environment, their morphological plasticity, originated from their various lifestyles and their incomparable capacity to adapt to a variety of environments, has made the identification of species challenging, even for expert taxonomists. Molecular approaches to species identification have allowed rapid detection, discrimination, and identification of cryptic or sibling species based on DNA sequence data. We examined sequence variation of a partial mitochondrial cytochrome C oxidase I gene (COI) from 133 copepod individuals collected from the Korean Peninsula, in order to identify and discriminate 94 copepod species covering six copepod orders of Calanoida, Cyclopoida, Harpacticoida, Monstrilloida, Poecilostomatoida and Siphonostomatoida. The results showed that there exists a clear gap with ca. 20 fold difference between the averages of within-specific sequence divergence (2.42%) and that of between-specific sequence divergence (42.79%) in COI, suggesting the plausible utility of this gene in delimitating copepod species. The results showed, with the COI barcoding data among 94 copepod species, that a copepod species could be distinguished from the others very clearly, only with four exceptions as followings: Mesocyclops dissimilis–Mesocyclops pehpeiensis (0.26% K2P distance in percent) and Oithona davisae–Oithona similis (1.1%) in Cyclopoida, Ostrincola japonica–Pseudomyicola spinosus (1.5%) in Poecilostomatoida, and Hatschekia japonica–Caligus quadratus (5.2%) in Siphonostomatoida. Thus, it strongly indicated that COI may be a useful tool in identifying various copepod species and make an initial progress toward the construction of a comprehensive DNA barcode database for copepods inhabiting the Korean Peninsula. PMID:27383475</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2009/1016/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2009/1016/"><span>Progress Report: Stratton Ecological Research Site - An Experimental Approach to Assess Effects of Various <span class="hlt">Grazing</span> Treatments on Vegetation and Wildlife Communities Across Managed Burns and Habitat Controls</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Erickson, Heidi J.; Aldridge, Cameron L.; Hobbs, N. Thompson</p> <p>2009-01-01</p> <p>Understanding how management practices affect wildlife is fundamental to wise decisions for conservation of public lands. Prescribed fire and <span class="hlt">grazing</span> timing are two management tools frequently used within publicly owned sagebrush ecosystems. We conducted a variety of surveys in order to assess the impacts of <span class="hlt">grazing</span> timing strategies (early summer before peak green-up, mid-summer at peak green-up, and late summer after peak green-up) in conjunction with prescribed fire on avian and small mammal populations in a high-elevation sagebrush ecosystem. Avian surveys resulted in a large detection sample size for three bird species: Brewer's sparrow (Spizella breweri), horned lark (Eremophila alpestris), and vesper sparrow (Pooecetes gramineus). Brewer's sparrows had the lowest number of detections within the mid-summer <span class="hlt">grazing</span> treatment compared to early and late summer <span class="hlt">grazing</span> treatments, while horned larks and vesper sparrows had higher detection frequencies within the late summer <span class="hlt">grazing</span> treatment. Summer and fall sage-grouse (Centrocercus urophasianus) pellet counts revealed that the greatest over-winter and over-summer use by sage-grouse occurred within the early summer <span class="hlt">grazing</span> treatment with minimal use of burn treatment areas across all <span class="hlt">grazing</span> treatments. Deer-mice (Peromyscus maniculatus) represented approximately 90 percent of small mammals captured and were most prevalent within the mid-summer <span class="hlt">grazing</span> treatment. Sagebrush cover was greatest within the mid-summer <span class="hlt">grazing</span> treatment. We monitored 50 and 103 nests in 2007 and 2008, respectively. The apparent success <span class="hlt">rate</span> for shrub-obligate nesting species was 58 percent in 2007 and 63 percent in 2008. This research will support management of sagebrush ecosystems by providing public land managers with direct comparisons of wildlife response to management regimes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20168609','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20168609"><span>Solar XUV <span class="hlt">grazing</span> incidence spectrograph on Skylab.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Garrett, D L; Tousey, R</p> <p>1977-04-01</p> <p>The objective of Skylab corollary experiment S020 was to obtain through the availability of long exposure times more complete information than was then available on the extreme ultraviolet (XUV) and soft x-ray spectrum of the sun in the 10-200-A range. The instrument was a small <span class="hlt">grazing</span> incidence spectrograph with photographic recording. Use was made of a novel split-ruled grating that combined 1200- and 2400-1/mm rulings to double the spectral coverage of the instrument and to aid in the measurement of wavelengths and order sorting. As it happened, there were many difficulties resulting from the major problems encountered by the Apollo and Skylab missions. Useful spectra were obtained, but the sensitivity of the instrument was greatly reduced, probably because of contamination resulting from leakage of the fluid used in the spacecraft cooling system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JMS....71..316C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JMS....71..316C"><span>Dynamics of suprabenthos-<span class="hlt">zooplankton</span> communities around the Balearic Islands (western Mediterranean): Influence of environmental variables and effects on the biological cycle of Aristeus antennatus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cartes, J. E.; Madurell, T.; Fanelli, E.; López-Jurado, J. L.</p> <p></p> <p> salinity close to the bottom, suggesting a link between suprabenthos abundance and changes in the oceanographic condition of water masses close to the bottom. It is suggested that a higher suprabenthos biomass recorded off Sóller in comparison to that off Cabrera in June could, in turn, be related to a seasonal inflow of Levantine Intermediate Water (LIW) in April-June in this area at mid bathyal depths (350-650 m). This trend would be based on: 1) it was evident only at mid-slope depths between 350-750 m, coinciding with the LIW distribution, and 2) it was not recorded among <span class="hlt">zooplankton</span> (collected throughout the water column). The possible effect of the fluctuations of suprabenthos and <span class="hlt">zooplankton</span> on higher trophic levels has been explored studying the diet and food consumption <span class="hlt">rates</span> of the red shrimp Aristeus antennatus, as indicator species by its dominance in bathyal communities. A. antennatus increased its food consumption from February to April-June 2004 off Sóller, which in the case of large (CL > 40 mm) specimens was found in both areas. In addition, there was a shift of diet from winter to spring-early summer. In this last period, A. antennatus preyed upon euphausiids and mesopelagic decapods and fish, while benthos (e.g. polychaetes and bivalves) decreased in the diet. This indicates an increase in the food consumption and probably in the caloric content of the diet in pre-spawning females in April-June 2004, which is synchronized with the period when gonad development begins in A. antennatus females (May-June). Anyway, macrozooplankton, and not suprabenthos, is crucial as a high energetic food source in the coupling between food intake and reproduction in the red shrimp.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028536','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028536"><span>Hydroacoustic estimation of <span class="hlt">zooplankton</span> biomass at two shoal complexes in the Apostle Islands Region of Lake Superior</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Holbrook, B.V.; Hrabik, T.R.; Branstrator, D.K.; Yule, D.L.; Stockwell, J.D.</p> <p>2006-01-01</p> <p>Hydroacoustics can be used to assess <span class="hlt">zooplankton</span> populations, however, backscatter must be scaled to be biologically meaningful. In this study, we used a general model to correlate site-specific hydroacoustic backscatter with <span class="hlt">zooplankton</span> dry weight biomass estimated from net tows. The relationship between <span class="hlt">zooplankton</span> dry weight and backscatter was significant (p < 0.001) and explained 76% of the variability in the dry weight data. We applied this regression to hydroacoustic data collected monthly in 2003 and 2004 at two shoals in the Apostle Island Region of Lake Superior. After applying the regression model to convert hydroacoustic backscatter to <span class="hlt">zooplankton</span> dry weight biomass, we used geostatistics to analyze the mean and variance, and ordinary kriging to create spatial <span class="hlt">zooplankton</span> distribution maps. The mean <span class="hlt">zooplankton</span> dry weight biomass estimates from plankton net tows and hydroacoustics were not significantly different (p = 0.19) but the hydroacoustic data had a significantly lower coefficient of variation (p < 0.001). The maps of <span class="hlt">zooplankton</span> distribution illustrated spatial trends in <span class="hlt">zooplankton</span> dry weight biomass that were not discernable from the overall means.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA573551','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA573551"><span>Field Demonstration of a Broadband Acoustical Backscattering System Mounted on a REMUS-100 for Inferences of <span class="hlt">Zooplankton</span> Size and Abundance</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2012-09-30</p> <p>particularly high, and that numerical abundance of <span class="hlt">zooplankton</span> was dominated by small copepods that were relatively evenly distributed throughout the water...column. Elastic-shelled pterapods and <span class="hlt">zooplankton</span> with gas-inclusions were not observed at significant abundances. Small copepods were distributed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006ECSS...67..424B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006ECSS...67..424B"><span>Size and species diversity of <span class="hlt">zooplankton</span> communities in fluctuating Mediterranean salt marshes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brucet, Sandra; Boix, Dani; López-Flores, Rocío; Badosa, Anna; Quintana, Xavier D.</p> <p>2006-04-01</p> <p>Differences in size and species diversity were analysed in a <span class="hlt">zooplankton</span> community of a Mediterranean salt marsh (Empordà wetlands, NE Iberian Peninsula), where the dominance of a single species was frequent. In the permanent salt marsh, species diversity and size diversity had similar patterns along <span class="hlt">zooplankton</span> succession. In the temporary salt marsh species diversity was high after flooding and diminished once water inputs ceased. As species diversity declined size diversity increased. Eventually, one species of calanoid dominated the <span class="hlt">zooplankton</span> community. The high size diversity in situations of calanoid dominance was possibly due to the co-occurrence of different developmental stages, each of which have different diets. Size diversity would thus indicate trophic niche segregation among different sizes. The combined use of species and size diversity values allows the identification of the successional phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028680','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028680"><span>Food habits of Juvenile American Shad and dynamics of <span class="hlt">zooplankton</span> in the lower Columbia River</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Haskell, C.A.; Tiffan, K.F.; Rondorf, D.W.</p> <p>2006-01-01</p> <p>As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected <span class="hlt">zooplankton</span> and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook salmon. Juvenile American shad were abundant and represented over 98% of the trawl catch in late summer. The five major taxa collected in <span class="hlt">zooplankton</span> tows were Bosmina longirostris, Daphnia, cyclopoid cope-pods, rotifers, and calanoid copepods. We evaluated total crustacean <span class="hlt">zooplankton</span> abundance and Daphnia biomass in relation to water temperature, flow, depth, diel period, and cross-sectional location using multiple regression. Differences in <span class="hlt">zooplankton</span> abundance were largely due to differences in water temperature and flow. Spatial variation in total <span class="hlt">zooplankton</span> abundance was observed in McNary Reservoir, but not in John Day Reservoir. Juvenile American shad generally fed on numerically abundant prey, despite being less preferred than larger bodied <span class="hlt">zooplankton</span>. A decrease in cladoceran abundance and size in August coupled with large percentages of Daphnia in juvenile American shad stomachs indicated heavy planktivory. Smaller juvenile American shad primarily fed on Daphnia in August, but switched to more evasive copepods as the mean size of fish increased and Daphnia abundance declined. Because Daphnia are particularly important prey items for subyearling Chinook salmon in mainstem reservoirs in mid to late summer, alterations in the cladoceran food base is of concern for the management of outmigrating salmonids and other Columbia River fishes. ?? 2006 by the Northwest Scientific Association. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PrOce..74..329F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PrOce..74..329F"><span><span class="hlt">Zooplankton</span> time-series in the Balearic Sea (Western Mediterranean): Variability during the decade 1994 2003</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández de Puelles, Maria Luz; Alemany, Francisco; Jansá, Javier</p> <p>2007-08-01</p> <p>Studies of plankton time-series from the Balearic islands waters are presented for the past decade, with main emphasis on the variability of <span class="hlt">zooplankton</span> and how it relates to the environment. The seasonal and interannual patterns of temperature, salinity, nutrients, chlorophyll concentration and <span class="hlt">zooplankton</span> abundance are described with data obtained between 1994 and 2003. Samples were collected every 10 days at a monitoring station in the Mallorca channel, an area with marked hydrographic variability in the Western Mediterranean. Mesoscale variability was also assessed using data from monthly sampling survey carried out between 1994 and 1999 in a three station transect located in the same study area. The copepods were the most abundant group with three higher peaks (March, May and September) distinguished during the annual cycle and a clear coastal-offshore decreasing gradient. Analysis of the <span class="hlt">zooplankton</span> community revealed two distinct periods: the mixing period during winter and early spring, where copepods, siphonophores and ostracods were most abundant and, the stratified period characterised by an increase of cladocerans and meroplankton abundances. Remarkable interannual <span class="hlt">zooplankton</span> variability was observed in relation to hydrographic regime with higher abundances of main groups during cool years, when northern Mediterranean waters prevailed in the area. The warmer years showed the lowest <span class="hlt">zooplankton</span> abundances, associated with the inflow of less saline and nutrient-depleted Atlantic Waters. Moreover, the correlation found between copepod abundance and large scale climatic factors (e.g., NAO) suggested that they act as main driver of the <span class="hlt">zooplankton</span> variability. Therefore, the seasonal but particularly the interannual variation observed in plankton abundance and structure patterns of the Balearic Sea seems to be highly modulated by large-scale forcing and can be considered an ideal place where to investigate potential consequences of global climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26774785','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26774785"><span>Moonlight Drives Ocean-Scale Mass Vertical Migration of <span class="hlt">Zooplankton</span> during the Arctic Winter.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Last, Kim S; Hobbs, Laura; Berge, Jørgen; Brierley, Andrew S; Cottier, Finlo</p> <p>2016-01-25</p> <p>In extreme high-latitude marine environments that are without solar illumination in winter, light-mediated patterns of biological migration have historically been considered non-existent [1]. However, diel vertical migration (DVM) of <span class="hlt">zooplankton</span> has been shown to occur even during the darkest part of the polar night, when illumination levels are exceptionally low [2, 3]. This paradox is, as yet, unexplained. Here, we present evidence of an unexpected uniform behavior across the entire Arctic, in fjord, shelf, slope and open sea, where vertical migrations of <span class="hlt">zooplankton</span> are driven by lunar illumination. A shift from solar-day (24-hr period) to lunar-day (24.8-hr period) vertical migration takes place in winter when the moon rises above the horizon. Further, mass sinking of <span class="hlt">zooplankton</span> from the surface waters and accumulation at a depth of ∼50 m occurs every 29.5 days in winter, coincident with the periods of full moon. Moonlight may enable predation of <span class="hlt">zooplankton</span> by carnivorous zooplankters, fish, and birds now known to feed during the polar night [4]. Although primary production is almost nil at this time, lunar vertical migration (LVM) may facilitate monthly pulses of carbon remineralization, as they occur continuously in illuminated mesopelagic systems [5], due to community respiration of carnivorous and detritivorous <span class="hlt">zooplankton</span>. The extent of LVM during the winter suggests that the behavior is highly conserved and adaptive and therefore needs to be considered as "baseline" <span class="hlt">zooplankton</span> activity in a changing Arctic ocean [6-9]. VIDEO ABSTRACT. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29696653','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29696653"><span>River flow, <span class="hlt">zooplankton</span> and dominant zooplanktivorous fish dynamics in a warm-temperate South African estuary.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mbandzi, N; Wasserman, R J; Deyzel, S H P; Vine, N G; Whitfield, A K</p> <p>2018-06-01</p> <p>The possible links between river flow, <span class="hlt">zooplankton</span> abundance and the responses of zooplanktivorous fishes to physico-chemical and food resource changes are assessed. To this end, the seasonal abundance, distribution and diet of the estuarine round-herring Gilchristella aestuaria and Cape silverside Atherina breviceps were studied in the Kariega Estuary. Spatio-temporal differences were determined for selected physico-chemical variables, <span class="hlt">zooplankton</span> abundance and zooplanktivorous fish abundance and distribution. Results indicated that, following a river flood event in winter (>30 m 3  s -1 ), altered physico-chemical conditions occurred throughout the estuary and depressed <span class="hlt">zooplankton</span> stocks. Abundance of G. aestuaria was highest in spring, with this species dominant in the upper and middle zones of the estuary, while A. breviceps was dominant in summer and preferred the middle and lower zones. The catch per unit of effort of both zooplanktivores also declined significantly following the flooding, thus suggesting that these fishes are reliant on <span class="hlt">zooplankton</span> as a primary food source for healthy populations. Copepods dominated the stomach contents of both fish species, indicating a potential for strong interspecific competition for food, particularly in the middle reaches. Temporal differences were evident in dietary overlap between the two zooplanktivorous fish species and were correlated with river flow, <span class="hlt">zooplankton</span> availability and fish distribution. The findings of this study emphasize the close trophic linkages between <span class="hlt">zooplankton</span> and zooplanktivorous fishes under changing estuarine environmental conditions, particularly river flow and provide important baseline information for similar studies elsewhere in South Africa and the rest of the world. © 2018 The Fisheries Society of the British Isles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28168098','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28168098"><span>Identifying <span class="hlt">zooplankton</span> community changes between shallow and upper-mesophotic reefs on the Mesoamerican Barrier Reef, Caribbean.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andradi-Brown, Dominic A; Head, Catherine E I; Exton, Dan A; Hunt, Christina L; Hendrix, Alicia; Gress, Erika; Rogers, Alex D</p> <p>2017-01-01</p> <p>Mesophotic coral ecosystems (MCEs, reefs 30-150 m) are understudied, yet the limited research conducted has been biased towards large sessile taxa, such as scleractinian corals and sponges, or mobile taxa such as fishes. Here we investigate <span class="hlt">zooplankton</span> communities on shallow reefs and MCEs around Utila on the southern Mesoamerican Barrier Reef using planktonic light traps. <span class="hlt">Zooplankton</span> samples were sorted into broad taxonomic groups. Our results indicate similar taxonomic <span class="hlt">zooplankton</span> richness and overall biomass between shallow reefs and MCEs. However, the abundance of larger bodied (>2 mm) <span class="hlt">zooplanktonic</span> groups, including decapod crab zoea, mysid shrimps and peracarid crustaceans, was higher on MCEs than shallow reefs. Our findings highlight the importance of considering <span class="hlt">zooplankton</span> when identifying broader reef community shifts across the shallow reef to MCE depth gradient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16161666','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16161666"><span>Comparison of airborne lidar measurements with 420 kHz echo-sounder measurements of <span class="hlt">zooplankton</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Churnside, James H; Thorne, Richard E</p> <p>2005-09-10</p> <p>Airborne lidar has the potential to survey large areas quickly and at a low cost per kilometer along a survey line. For this reason, we investigated the performance of an airborne lidar for surveys of <span class="hlt">zooplankton</span>. In particular, we compared the lidar returns with echo-sounder measurements of <span class="hlt">zooplankton</span> in Prince William Sound, Alaska. Data from eight regions of the Sound were compared, and the correlation between the two methods was 0.78. To obtain this level of agreement, a threshold was applied to the lidar return to remove the effects of scattering from phytoplankton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PrOce.130..205T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PrOce.130..205T"><span><span class="hlt">Zooplankton</span> fecal pellets, marine snow, phytodetritus and the ocean's biological pump</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turner, Jefferson T.</p> <p>2015-01-01</p> <p>The 'biological pump' is the process by which photosynthetically-produced organic matter in the ocean descends from the surface layer to depth by a combination of sinking particles, advection or vertical mixing of dissolved organic matter, and transport by animals. Particulate organic matter that is exported downward from the euphotic zone is composed of combinations of fecal pellets from <span class="hlt">zooplankton</span> and fish, organic aggregates known as 'marine snow' and phytodetritus from sinking phytoplankton. Previous reviews by Turner and Ferrante (1979) and Turner (2002) focused on publications that appeared through late 2001. Since that time, studies of the biological pump have continued, and there have been >300 papers on vertical export flux using sediment traps, large-volume filtration systems and other techniques from throughout the global ocean. This review will focus primarily on recent studies that have appeared since 2001. Major topics covered in this review are (1) an overview of the biological pump, and its efficiency and variability, and the role of dissolved organic carbon in the biological pump; (2) <span class="hlt">zooplankton</span> fecal pellets, including the contribution of <span class="hlt">zooplankton</span> fecal pellets to export flux, epipelagic retention of <span class="hlt">zooplankton</span> fecal pellets due to <span class="hlt">zooplankton</span> activities, <span class="hlt">zooplankton</span> vertical migration and fecal pellet repackaging, microbial ecology of fecal pellets, sinking velocities of fecal pellets and aggregates, ballasting of sinking particles by mineral contents, phytoplankton cysts, intact cells and harmful algae toxins in fecal pellets, importance of fecal pellets from various types of <span class="hlt">zooplankton</span>, and the role of <span class="hlt">zooplankton</span> fecal pellets in picoplankton export; (3) marine snow, including the origins, abundance, and distributions of marine snow, particles and organisms associated with marine snow, consumption and fragmentation of marine snow by animals, pathogens associated with marine snow; (4) phytodetritus, including pulsed export of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS51F..08L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS51F..08L"><span>Methyl mercury uptake by diverse marine phytoplankton and trophic transfer to <span class="hlt">zooplankton</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, C. S.; Fisher, N. S.</p> <p>2014-12-01</p> <p>While it is well known that methylmercury (MeHg) biomagnifies in aquatic food chains, few studies have quantified its bioaccumulation in marine phytoplankton from seawater, even though that is overwhelmingly the largest bioaccumulation step. Aquatic animals acquire MeHg mainly from dietary exposure and it is important to evaluate the bioaccumulation of this compound in planktonic organisms that form the base of marine food webs. We used a gamma-emitting radioisotope, 203Hg, to assess the <span class="hlt">rate</span> and extent of MeHg uptake in marine diatoms, dinoflagellates, coccolithophores, cryptophytes chlorophytes, and cyanobacteria held in unialgal cultures under varying temperature and light conditions. For experimental conditions in which the dissolved MeHg was at 300 pM, the uptake <span class="hlt">rates</span> in all species ranged from 0.004 to 0.75 amol Hg μm-3 cell volume d-1 and reached steady state within 2 d. Volume concentration factors (VCFs) ranged from 0.4 to 60 x 105 for the different species. Temperature and light conditions had no direct effect on cellular MeHg uptake but ultimately affected growth of the cells, resulting in greater suspended particulate matter and associated MeHg. VCFs strongly correlated with cell surface area to volume ratios in all species. Assimilation efficiencies of MeHg from phytoplankton food (Thalassiosira pseudonana, Dunaliella tertiolecta and Rhodomonas salina) in a marine copepod grazer (Acartia tonsa) ranged from 74 to 92%, directly proportional to the cytoplasmic partitioning of MeHg in the phytoplankton cells. MeHg uptake in copepods from the aqueous phase was low and modeling shows that nearly all the MeHg acquired by this zooplankter is from diet. Herbivorous <span class="hlt">zooplankton</span> can be an important link from phytoplankton at the base of the food web to fish higher in the food chain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70171286','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70171286"><span>Changes in seasonal nearshore <span class="hlt">zooplankton</span> abundance patterns in Lake Ontario following establishment of the exotic predator Cercopagis pengoi</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Warner, David M.; Rudstam, Lars G.; Benoit, Hugues; Mills, Edward L.; Johannsson, Ora E.</p> <p>2006-01-01</p> <p>Cercopagis pengoi, a zooplanktivore first discovered in Lake Ontario in 1998, may reduce availability of prey for planktivorous fish. Cercoapgis pengoi is most abundant in late summer and fall. Therefore, we hypothesized that abundance of small <span class="hlt">zooplankton</span> (bosminids and cyclopoids) species would decrease at that time. To determine if the establishment of C. pengoi was followed by changes in the <span class="hlt">zooplankton</span> community, seasonal patterns in nearshore <span class="hlt">zooplankton</span> collected from May to October 1995–2000 were examined. Early summer density of small <span class="hlt">zooplankton</span> was similar in all years while late summer and fall densities were significantly lower in 1998–2000 than in 1995–1997. The declines of small <span class="hlt">zooplankton</span> coincided seasonally with the peak in C. pengoidensity. Other possible causes for the observed changes in small <span class="hlt">zooplankton</span> are less likely. High levels of fish predation should have resulted in smaller <span class="hlt">zooplankton</span> in 1998–2000 than in 1995–1997 and larger declines in Daphnia than other groups. This was not observed. There was no significant decline in chlorophyll-a concentrations or changes in temperature between 1995–1997 and 1998–2000. Therefore, the declines in density of small <span class="hlt">zooplankton</span> were most likely the result of C. pengoi predation. The effect of C. pengoi establishment on alewives is increased competition for <span class="hlt">zooplankton</span> prey but C. pengoi has replaced a portion of the <span class="hlt">zooplankton</span> biomass and adult alewife diet formerly dominated by Diacyclops thomasi and Bosmina longirostris.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..104....1H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..104....1H"><span><span class="hlt">Zooplankton</span> trophic niches respond to different water types of the western Tasman Sea: A stable isotope analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henschke, Natasha; Everett, Jason D.; Suthers, Iain M.; Smith, James A.; Hunt, Brian P. V.; Doblin, Martina A.; Taylor, Matthew D.</p> <p>2015-10-01</p> <p>The trophic relationships of 21 species from an oceanic <span class="hlt">zooplankton</span> community were studied using stable isotopes of carbon and nitrogen. <span class="hlt">Zooplankton</span> and suspended particulate organic matter (POM) were sampled in three different water types in the western Tasman Sea: inner shelf (IS), a cold core eddy (CCE) and a warm core eddy (WCE). δ15N values ranged from 3.9‰ for the parasitic copepod Sapphirina augusta to 10.2‰ for the euphausiid, Euphausia spinifera. δ13C varied from -22.6 to -19.4‰ as a result of the copepod Euchirella curticauda and E. spinifera. The isotopic composition of POM varied significantly among water types; as did the trophic enrichment of <span class="hlt">zooplankton</span> over POM, with the lowest enrichment in the recently upwelled IS water type (0.5‰) compared to the warm core eddy (1.6‰) and cold core eddy (2.7‰). The WCE was an oligotrophic environment and was associated with an increased trophic level for omnivorous <span class="hlt">zooplankton</span> (copepods and euphausiids) to a similar level as carnivorous <span class="hlt">zooplankton</span> (chaetognaths). Therefore carnivory in <span class="hlt">zooplankton</span> can increase in response to lower abundance and reduced diversity in their phytoplankton and protozoan prey. Trophic niche width comparisons across three <span class="hlt">zooplankton</span> species: the salp Thalia democratica, the copepod Eucalanus elongatus and the euphausiid Thysanoessa gregaria, indicated that both niche partitioning and competition can occur within the <span class="hlt">zooplankton</span> community. We have shown that trophic relationships among the <span class="hlt">zooplankton</span> are dynamic and respond to different water types. The changes to the <span class="hlt">zooplankton</span> isotopic niche, however, were still highly variable as result of oceanographic variation within water types.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15542487','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15542487"><span>Productivity of cow-calf pairs <span class="hlt">grazing</span> tall fescue pastures infected with either the wild-type endophyte or a nonergot alkaloid-producing endophyte strain, AR542.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Watson, R H; McCann, M A; Parish, J A; Hoveland, C S; Thompson, F N; Bouton, J H</p> <p>2004-11-01</p> <p>The nonergot alkaloid-producing endo-phyte, AR542, has been shown to improve the persistence and yield of tall fescue pastures without causing the animal disorders commonly associated with tall fescue toxicosis. A 3-yr <span class="hlt">grazing</span> study was conducted to compare effects of AR542-infected tall fescue pastures with wild type endophyte-infected (E+) tall fescue pastures on cow-calf performance. Replicated 7.3-ha pastures of each treatment were <span class="hlt">grazed</span> by cow-calf pairs (16 pairs per pasture replication) each year from March to weaning in September. The cows were exposed to breeding on their respective pasture treatments from April 1 through June 15. The treatment groups were compared for reproductive performance, ADG, BCS, calf growth <span class="hlt">rate</span>, and weaning weight. Blood samples were also collected for serum prolactin (PRL) analysis. There were no significant differences in calving <span class="hlt">rate</span> (P = 0.98) or calving interval (P = 0.62) between pasture treatments. Cows that <span class="hlt">grazed</span> the AR542 pastures subsequently gave birth to calves that were heavier (P < 0.05) than calves from cows that had <span class="hlt">grazed</span> the E+ pastures. Cows <span class="hlt">grazing</span> the AR542 pastures had higher (P < 0.05) BCS at the end of the <span class="hlt">grazing</span> period, and had higher ADG during the <span class="hlt">grazing</span> period. Calves raised on the AR542 pasture had higher (P < 0.05) ADG and weaning weights than calves of the same sex raised on the E+ pastures. Serum PRL concentrations were decreased (P < 0.05) in both cows and calves on the E+ pastures compared with serum PRL concentrations in cows and calves <span class="hlt">grazing</span> the AR542 pastures. The results indicate that <span class="hlt">grazing</span> tall fescue pastures infected with the AR542 endophyte may give significant advantages in cow-calf growth <span class="hlt">rates</span> and BCS over <span class="hlt">grazing</span> E+ pastures. However, there did not seem to be any benefit in reproductive performance in this trial. There was a small, but significant increase in birth weight in cows <span class="hlt">grazing</span> AR542 pasture.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22916937','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22916937"><span>Meta-analysis of the effect of pregrazing pasture mass on pasture intake, milk production, and <span class="hlt">grazing</span> behavior of dairy cows strip-<span class="hlt">grazing</span> temperate grasslands.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pérez-Prieto, L A; Delagarde, R</p> <p>2012-09-01</p> <p> in pasture intake <span class="hlt">rate</span>. Pasture intake <span class="hlt">rate</span> increased with increasing PM at SPA(0) but decreased with increasing PM at SPA(5). This meta-analysis clearly demonstrates that the effects of PM on pasture intake, milk production, and behavior of strip-<span class="hlt">grazing</span> dairy cows depend largely on the height at which the PM and pasture allowance are measured. These results have methodological implications for future <span class="hlt">grazing</span> research because it can be recommended that PM be compared at similar levels of pasture availability (i.e., at the same pasture allowance above 2 to 3 cm) to avoid possible misinterpretations of results. They also reveal the benefits of improving <span class="hlt">grazing</span> management and intake prediction through modeling in pasture-based dairy systems. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=338694','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=338694"><span>Impact of processing on in vitro digestion of milk from <span class="hlt">grazing</span> organic and confined conventional herds</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Debate on differences between milk from <span class="hlt">grazing</span> and non-<span class="hlt">grazing</span> cows has not addressed the effects that standard processing may have on milk digestibility. In this study, raw milk from <span class="hlt">grazing</span> organic (ORG) and non-<span class="hlt">grazing</span> conventional (CONV) herds was adjusted to 0 and 3.25% fat and processed as fo...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=338830','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=338830"><span>Fall and spring <span class="hlt">grazing</span> influence fire ignitability and initial spread in shrub steppe communities</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>The interaction between <span class="hlt">grazing</span> and fire influences ecosystems around the world. However, relatively little is known about the influence of <span class="hlt">grazing</span> on fire, in particular ignition and initial spread and how it varies by <span class="hlt">grazing</span> management differences. We investigated effects of fall <span class="hlt">grazing</span>, spring...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/35708','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/35708"><span>Willow establishment in relation to cattle <span class="hlt">grazing</span> on an eastern Oregon stream</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Nancy L. Shaw; Warren P. Clary</p> <p>1996-01-01</p> <p>Natural regeneration and growth of coyote willow (Salix exigua Nutt. ssp. exigua) and whiplash willow (S. lasiandra Bemth. var. caudata [Nutt.] Sudw.) were monitored from 1987 to 1993 on a low-elevation eastern Oregon stream degraded by more than a century of heavy livestock <span class="hlt">grazing</span>. Treatments were no <span class="hlt">grazing</span>, moderate spring <span class="hlt">grazing</span>, moderate fall <span class="hlt">grazing</span>, and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol1/pdf/CFR-2010-title25-vol1-sec161-207.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title25-vol1/pdf/CFR-2010-title25-vol1-sec161-207.pdf"><span>25 CFR 161.207 - What livestock are authorized to <span class="hlt">graze</span>?</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... 25 Indians 1 2010-04-01 2010-04-01 false What livestock are authorized to <span class="hlt">graze</span>? 161.207 Section... LANDS <span class="hlt">GRAZING</span> PERMITS General Provisions § 161.207 What livestock are authorized to <span class="hlt">graze</span>? The following livestock are authorized to <span class="hlt">graze</span> on the Navajo Partitioned Lands: horses, cattle, sheep, goats, mules...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BGD....12.6285Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BGD....12.6285Z"><span>Seasonal and size-dependent variations in the phytoplankton growth and microzooplankton <span class="hlt">grazing</span> in the southern South China Sea under the influence of the East Asian monsoon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, L.; Tan, Y.; Huang, L.; Hu, Z.; Ke, Z.</p> <p>2015-04-01</p> <p>To examine seasonal and size-dependent variations in the phytoplankton growth and microzooplankton <span class="hlt">grazing</span> in oligotrophic tropical waters under the influence of seasonal reversing monsoon, dilution experiments were conducted during the summer 2009 (21 May to 9 June) and winter 2010 (9 to 18 November) in the southern South China Sea (SSCS). The results showed that environmental variables, phytoplankton biomass, phytoplankton growth <span class="hlt">rate</span> (μ), microzooplankton <span class="hlt">grazing</span> <span class="hlt">rate</span> (m), and correlationship (coupling) between the μ and m, but the microzooplankton <span class="hlt">grazing</span> impact on phytoplankton (m/μ) significantly varied between the two seasons. Higher relative preference index (RPI) for and m on the larger-sized (>3 μm) phytoplankton than pico-phytoplankton (<3 μm), indicating significant size-selective <span class="hlt">grazing</span> by microzooplankton on the larger-sized phytoplankton, were also observed. The μ and m were significantly correlated with salinity and dissolved inorganic nutrients, which indicated that salient seasonal variations in the phytoplankton growth and microzooplankton <span class="hlt">grazing</span> in the SSCS were closely related to the environmental variables under the influence of the East Asian monsoon. We propose that intermittent arrivals of the northeast winter monsoon could lead to the low μ and m, and the decoupling between the μ and m in the SSCS, through influencing nutrient supply to the surface water, and inducing surface seawater salinity decrease. The low m/μ (<50% on average) indicates low remineralization of organic matter mediated by microzooplankton and the increased importance of the phytoplankton-mesozooplankton <span class="hlt">grazing</span> pathway, and thus probably accounts for part of the high vertical biogenic particle fluxes in the prevailing periods of the monsoons in the SSCS. The size-selective <span class="hlt">grazing</span> suggests that microzooplankton <span class="hlt">grazing</span> contributes to the pico-phytoplankton dominance in the oligotrophic tropical waters such as that of the SSCS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29468318','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29468318"><span>How <span class="hlt">grazing</span> affects soil quality of soils formed in the glaciated northeastern United States.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cox, Alissa H; Amador, José A</p> <p>2018-02-21</p> <p>Historically, much of the New England landscape was converted to pasture for <span class="hlt">grazing</span> animals and harvesting hay. Both consumer demand for local sustainably produced food, and the number of small farms is increasing in RI, highlighting the importance of characterizing the effects livestock have on the quality of pasture soils. To assess how livestock affect pasture on Charlton and Canton soils series in RI, we examined soil quality in farms raising beef cattle (Bos taurus), sheep (Ovis aries), and horses (Equus ferus caballus), using hayed pastures as a control. We sampled three pastures per livestock type and three control hayed pastures in May, August, and October 2012. Hay fields and pastures <span class="hlt">grazed</span> by sheep had statistically significant (P < 0.001) better soil quality than pastures <span class="hlt">grazed</span> by beef cattle or horses. This was driven by parameters including penetration resistance, bulk density, aggregate stability, and infiltration <span class="hlt">rate</span>. Hayfields also showed higher soil quality measures than <span class="hlt">grazed</span> pastures for organic matter content and active C. In addition, significant differences in nitrate and phosphate concentrations were observed among livestock types. Respiration and infiltration <span class="hlt">rates</span>, pH, and ammonium concentrations, on the other hand, did not differ significantly among pasture types. When all soil quality indicators in this study were weighed equally, soil quality scores followed the order: hay > sheep > beef cattle > horses. The results of our study provide baseline data on the effect different types of livestock have on pasture soil quality in RI, which may be useful in making sound land use and agricultural management decisions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017BGeo...14.5633O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017BGeo...14.5633O"><span>The effects of burning and <span class="hlt">grazing</span> on soil carbon dynamics in managed Peruvian tropical montane grasslands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oliver, Viktoria; Oliveras, Imma; Kala, Jose; Lever, Rebecca; Arn Teh, Yit</p> <p>2017-12-01</p> <p>Montane tropical soils are a large carbon (C) reservoir, acting as both a source and a sink of CO2. Enhanced CO2 emissions originate, in large part, from the decomposition and losses of soil organic matter (SOM) following anthropogenic disturbances. Therefore, quantitative knowledge of the stabilization and decomposition of SOM is necessary in order to understand, assess and predict the impact of land management in the tropics. In particular, labile SOM is an early and sensitive indicator of how SOM responds to changes in land use and management practices, which could have major implications for long-term carbon storage and rising atmospheric CO2 concentrations. The aim of this study was to investigate the impacts of <span class="hlt">grazing</span> and fire history on soil C dynamics in the Peruvian montane grasslands, an understudied ecosystem, which covers approximately a quarter of the land area in Peru. A density fractionation method was used to quantify the labile and stable organic matter pools, along with soil CO2 flux and decomposition measurements. <span class="hlt">Grazing</span> and burning together significantly increased soil CO2 fluxes and decomposition <span class="hlt">rates</span> and reduced temperature as a driver. Although there was no significant effect of land use on total soil C stocks, the combination of burning and <span class="hlt">grazing</span> decreased the proportion of C in the free light fraction (LF), especially at the lower depths (10-20 and 20-30 cm). In the control soils, 20 % of the material recovered was in the free LF, which contained 30 % of the soil C content. In comparison, the burnt-<span class="hlt">grazed</span> soil had the smallest recovery of the free LF (10 %) and a significantly lower C content (14 %). The burnt soils had a much higher proportion of C in the occluded LF (12 %) compared to the not-burnt soils (7 %) and there was no significant difference among the treatments in the heavy fraction (F) ( ˜ 70 %). The synergistic effect of burning and <span class="hlt">grazing</span> caused changes to the soil C dynamics. CO2 fluxes were increased and the dominant</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29153162','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29153162"><span>A 100-Year Review: A century of change in temperate <span class="hlt">grazing</span> dairy systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roche, J R; Berry, D P; Bryant, A M; Burke, C R; Butler, S T; Dillon, P G; Donaghy, D J; Horan, B; Macdonald, K A; Macmillan, K L</p> <p>2017-12-01</p> <p>From 1917 to 2017, dairy <span class="hlt">grazing</span> systems have evolved from uncontrolled <span class="hlt">grazing</span> of unimproved pastures by dual-purpose dairy-beef breeds to an intensive system with a high output per unit of land from a fit-for-purpose cow. The end of World War I signaled significant government investments in agricultural research institutes around the world, which coincided with technological breakthroughs in milk harvesting and a recognition that important traits in both plants and animals could be improved upon relatively rapidly through genetic selection. Uptake of milk recording and herd testing increased rapidly through the 1920s, as did the recognition that pastures that were rested in between <span class="hlt">grazing</span> events yielded more in a year than those continuously <span class="hlt">grazed</span>. This, and the invention and refinement of the electric fence, led to the development of "controlled" rotational <span class="hlt">grazing</span>. This, in itself, facilitated greater stocking <span class="hlt">rates</span> and a 5 to 10% increase in milk output per hectare but, perhaps more importantly, it allowed a more efficient use of nitrogen fertilizer, further increasing milk output/land area by 20%. Farmer inventions led to the development of the herringbone and rotary milking parlors, which, along with the "unshortable" electric fence and technological breakthroughs in sperm dilution <span class="hlt">rates</span>, allowed further dairy farm expansion. Simple but effective technological breakthroughs in reproduction ensured that cows were identified in estrus early (a key factor in maintaining the seasonality of milk production) and enabled researchers to quantify the anestrus problem in <span class="hlt">grazing</span> herds. Genetic improvement of pasture species has lagged its bovine counterpart, but recent developments in multi-trait indices as well as investment in genetic technologies should significantly increase potential milk production per hectare. Decades of research on the use of feeds other than pasture (i.e., supplementary feeds) have provided consistent milk production responses when the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec4110-2-3.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec4110-2-3.pdf"><span>43 CFR 4110.2-3 - Transfer of <span class="hlt">grazing</span> preference.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... property and the <span class="hlt">grazing</span> preference, in animal unit months, attached to that base property. (c) If a... the transfer. (e) If an unqualified transferee acquires rights in base property through operation of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec4110-2-3.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec4110-2-3.pdf"><span>43 CFR 4110.2-3 - Transfer of <span class="hlt">grazing</span> preference.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... property and the <span class="hlt">grazing</span> preference, in animal unit months, attached to that base property. (c) If a... the transfer. (e) If an unqualified transferee acquires rights in base property through operation of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=320988','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=320988"><span>Pasture-scale measurement of methane emissions of <span class="hlt">grazing</span> cattle</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Quantifying methane emission of cattle <span class="hlt">grazing</span> on southern Great Plains pastures using micrometeorology presents several challenges. Cattle are elevated, mobile point sources of methane, so that knowing their location in relation to atmospheric methane concentration measurements becomes critical. St...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec4710-5.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title43-vol2/pdf/CFR-2011-title43-vol2-sec4710-5.pdf"><span>43 CFR 4710.5 - Closure to livestock <span class="hlt">grazing</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock <span class="hlt">grazing</span>. (a) If...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec4710-5.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title43-vol2/pdf/CFR-2013-title43-vol2-sec4710-5.pdf"><span>43 CFR 4710.5 - Closure to livestock <span class="hlt">grazing</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock <span class="hlt">grazing</span>. (a) If...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title43-vol2/pdf/CFR-2014-title43-vol2-sec4710-5.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title43-vol2/pdf/CFR-2014-title43-vol2-sec4710-5.pdf"><span>43 CFR 4710.5 - Closure to livestock <span class="hlt">grazing</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock <span class="hlt">grazing</span>. (a) If...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec4710-5.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title43-vol2/pdf/CFR-2012-title43-vol2-sec4710-5.pdf"><span>43 CFR 4710.5 - Closure to livestock <span class="hlt">grazing</span>.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock <span class="hlt">grazing</span>. (a) If...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3963030','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3963030"><span>Sound management may sequester methane in <span class="hlt">grazed</span> rangeland ecosystems</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Chengjie; Han, Guodong; Wang, Shiping; Zhai, Xiajie; Brown, Joel; Havstad, Kris M.; Ma, Xiuzhi; Wilkes, Andreas; Zhao, Mengli; Tang, Shiming; Zhou, Pei; Jiang, Yuanyuan; Lu, Tingting; Wang, Zhongwu; Li, Zhiguo</p> <p>2014-01-01</p> <p>Considering their contribution to global warming, the sources and sinks of methane (CH4) should be accounted when undertaking a greenhouse gas inventory for <span class="hlt">grazed</span> rangeland ecosystems. The aim of this study was to evaluate the mitigation potential of current ecological management programs implemented in the main rangeland regions of China. The influences of rangeland improvement, utilization and livestock production on CH4 flux/emission were assessed to estimate CH4 reduction potential. Results indicate that the <span class="hlt">grazed</span> rangeland ecosystem is currently a net source of atmospheric CH4. However, there is potential to convert the ecosystem to a net sink by improving management practices. Previous assessments of capacity for CH4 uptake in <span class="hlt">grazed</span> rangeland ecosystems have not considered improved livestock management practices and thus underestimated potential for CH4 uptake. Optimal fertilization, rest and light <span class="hlt">grazing</span>, and intensification of livestock management contribute mitigation potential significantly. PMID:24658176</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24658176','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24658176"><span>Sound management may sequester methane in <span class="hlt">grazed</span> rangeland ecosystems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Chengjie; Han, Guodong; Wang, Shiping; Zhai, Xiajie; Brown, Joel; Havstad, Kris M; Ma, Xiuzhi; Wilkes, Andreas; Zhao, Mengli; Tang, Shiming; Zhou, Pei; Jiang, Yuanyuan; Lu, Tingting; Wang, Zhongwu; Li, Zhiguo</p> <p>2014-03-24</p> <p>Considering their contribution to global warming, the sources and sinks of methane (CH4) should be accounted when undertaking a greenhouse gas inventory for <span class="hlt">grazed</span> rangeland ecosystems. The aim of this study was to evaluate the mitigation potential of current ecological management programs implemented in the main rangeland regions of China. The influences of rangeland improvement, utilization and livestock production on CH4 flux/emission were assessed to estimate CH4 reduction potential. Results indicate that the <span class="hlt">grazed</span> rangeland ecosystem is currently a net source of atmospheric CH4. However, there is potential to convert the ecosystem to a net sink by improving management practices. Previous assessments of capacity for CH4 uptake in <span class="hlt">grazed</span> rangeland ecosystems have not considered improved livestock management practices and thus underestimated potential for CH4 uptake. Optimal fertilization, rest and light <span class="hlt">grazing</span>, and intensification of livestock management contribute mitigation potential significantly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=233339&keyword=nursery&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=233339&keyword=nursery&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span><span class="hlt">Zooplankton</span> Linkages between Rivers and Great Lakes: Case Study from the St. Louis River</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>In this case study, we characterized the spatial and seasonal distribution and abundance of <span class="hlt">zooplankton</span> within the hydrologically complex drowned river mouth of the St. Louis River, the second largest tributary to Lake Superior and an important fish nursery. We hypothesize that z...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5191104','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5191104"><span>Looking inside the Ocean: Toward an Autonomous Imaging System for Monitoring Gelatinous <span class="hlt">Zooplankton</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Corgnati, Lorenzo; Marini, Simone; Mazzei, Luca; Ottaviani, Ennio; Aliani, Stefano; Conversi, Alessandra; Griffa, Annalisa</p> <p>2016-01-01</p> <p>Marine plankton abundance and dynamics in the open and interior ocean is still an unknown field. The knowledge of gelatinous <span class="hlt">zooplankton</span> distribution is especially challenging, because this type of plankton has a very fragile structure and cannot be directly sampled using traditional net based techniques. To overcome this shortcoming, Computer Vision techniques can be successfully used for the automatic monitoring of this group.This paper presents the GUARD1 imaging system, a low-cost stand-alone instrument for underwater image acquisition and recognition of gelatinous <span class="hlt">zooplankton</span>, and discusses the performance of three different methodologies, Tikhonov Regularization, Support Vector Machines and Genetic Programming, that have been compared in order to select the one to be run onboard the system for the automatic recognition of gelatinous <span class="hlt">zooplankton</span>. The performance comparison results highlight the high accuracy of the three methods in gelatinous <span class="hlt">zooplankton</span> identification, showing their good capability in robustly selecting relevant features. In particular, Genetic Programming technique achieves the same performances of the other two methods by using a smaller set of features, thus being the most efficient in avoiding computationally consuming preprocessing stages, that is a crucial requirement for running on an autonomous imaging system designed for long lasting deployments, like the GUARD1. The Genetic Programming algorithm has been installed onboard the system, that has been operationally tested in a two-months survey in the Ligurian Sea, providing satisfactory results in terms of monitoring and recognition performances. PMID:27983638</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EnMan..60.1127G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EnMan..60.1127G"><span>Emergent Macrophytes Support <span class="hlt">Zooplankton</span> in a Shallow Tropical Lake: A Basis for Wetland Conservation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gebrehiwot, Mesfin; Kifle, Demeke; Triest, Ludwig</p> <p>2017-12-01</p> <p>Understanding the biodiversity value of littoral zones of lakes is a priority for aquatic biodiversity conservation. However, less emphasis has been given to the littoral part of tropical African lakes, with many of the previous researches focusing only on the open water side. The aim of the present study was, therefore, to investigate the impact of the littoral zone of a shallow freshwater tropical lake (Ziway, Ethiopia), dominated by two emergent macrophytes, on <span class="hlt">zooplankton</span> community structure. We hypothesized that the wetland vegetation serves as a preferred microhabitat for <span class="hlt">zooplankton</span> communities. A lake with substantial coverage of emergent macrophytes was monitored monthly from January to August, 2016. The monitoring included the measurements of physical, chemical, and biological parameters. Sampling sites were selected to represent areas of the macrophyte vegetation ( Typha latifolia and Phragmites australis) and the open water part of the lake. Sites with macrophyte vegetation were found to be the home of more dense and diverse <span class="hlt">zooplankton</span> community. However, during the period of high vegetation loss, the density of crustacean <span class="hlt">zooplankton</span> showed significant reduction within the patches of macrophytes. From biodiversity conservation perspective, it was concluded that the preservation of such small areas of macrophytes covering the littoral zone of lakes could be as important as protecting the whole lake. However, the rapid degradation of wetland vegetation by human activities is a real threat to the lake ecosystem. In the not-too-far future, it could displace and evict riparian vegetation and the biota it supports.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ECSS...78..739I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ECSS...78..739I"><span>Annual cycle of <span class="hlt">zooplankton</span> abundance and species composition in Izmit Bay (the northeastern Marmara Sea)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Isinibilir, Melek; Kideys, Ahmet E.; Tarkan, Ahmet N.; Yilmaz, I. Noyan</p> <p>2008-07-01</p> <p>The monthly abundance, biomass and taxonomic composition of <span class="hlt">zooplankton</span> of Izmit Bay (the northeastern Marmara Sea) were studied from October 2001 to September 2002. Most species within the <span class="hlt">zooplankton</span> community displayed a clear pattern of succession throughout the year. Generally copepods and cladocerans were the most abundant groups, while the contribution of meroplankton increased at inner-most stations and dominated the <span class="hlt">zooplankton</span>. Both species number ( S) and diversity ( H') were positively influenced by the increase in salinity of upper layers ( r = 0.30 and r = 0.31, p < 0.001, respectively), while chlorophyll a was negatively affected ( r = -0.36, p < 0.001). Even though Noctiluca scintillans had a significant seasonality ( F11,120 = 8.45, p < 0.001, ANOVA), abundance was not related to fluctuations in temperature and only chlorophyll a was adversely correlated ( r = -0.35, p < 0.001). In general, there are some minor differences in <span class="hlt">zooplankton</span> assemblages of upper and lower layers. A comparison of the species composition and abundance of Izmit Bay with other Black Sea bays reveals a high similarity between them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PrOce.159...73B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PrOce.159...73B"><span>Mercury concentration variability in the <span class="hlt">zooplankton</span> of the southern Baltic coastal zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bełdowska, Magdalena; Mudrak-Cegiołka, Stella</p> <p>2017-12-01</p> <p>Being a toxic element, mercury is introduced to the human organism through the consumption of fish and seafood, which in turn often feed on <span class="hlt">zooplankton</span>. The bioaccumulation of Hg by <span class="hlt">zooplankton</span> is an important factor influencing the magnitude of the mercury load introduced with food into the predator organism. Therefore the present article attempts to identify the processes and factors influencing Hg concentration in the <span class="hlt">zooplankton</span> of the coastal zone, an area where marine organisms - an attractive food source for humans - thrive. This is particularly important in areas where climate changes influence the species composition and quantity of plankton. The studies were carried out on three test sites in the coastal zone of the southern Baltic Sea in the period from December 2011 to May 2013. The obtained results show that the shorting of the winter season is conducive to Hg increase in <span class="hlt">zooplankton</span> and, consequently, in the trophic chain. High mercury concentrations were measured in genus Synchaeta and Keratella when Mesodinium rubrum were predominant in phytoplankton, while other sources of this metal in the plankton fauna were epilithon, epiphton and microbenthos. This is of particular importance when it comes to sheltered bays and estuaries with low water dynamics.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=62597&keyword=opc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=62597&keyword=opc&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span><span class="hlt">ZOOPLANKTON</span> SIZE-SPECTRA AS AN INDICATOR IN GREAT LAKES COASTAL WATERS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p><span class="hlt">Zooplankton</span> size-spectra has the potential to be used as an indicator of ecological condition. Mean size and size-distribution are effected by planktivore pressure and therefore reflect trophic cascade interactions as well as size selective predation. We used an optical plankton ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=331157&keyword=HUMAN+AND+RESOURCE&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=331157&keyword=HUMAN+AND+RESOURCE&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Development of a Multimetric Indicator of Pelagic <span class="hlt">Zooplankton</span> Assemblage Condition for the 2012 National Lakes Assessment</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>We used <span class="hlt">zooplankton</span> data collected for the 2012 National Lakes Assessment (NLA) to develop multimetric indices (MMIs) for five aggregated ecoregions of the conterminous USA (Coastal Plains, Eastern Highlands, Plains, Upper Midwest, and Western Mountains and Xeric [“West&rsq...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/1001082','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/1001082"><span>Spatial patterns in assemblage structures of pelagic forage fish and <span class="hlt">zooplankton</span> in western Lake Superior</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Johnson, Timothy B.; Hoff, Michael H.; Trebitz, Anett S.; Bronte, Charles R.; Corry, Timothy D.; Kitchell, James F.; Lozano, Stephen J.; Mason, Doran M.; Scharold, Jill V.; Schram, Stephen T.; Schreiner, Donald R.</p> <p>2004-01-01</p> <p>We assessed abundance, size, and species composition of forage fish and <span class="hlt">zooplankton</span> communities of western Lake Superior during August 1996 and July 1997. Data were analyzed for three ecoregions (Duluth-Superior, Apostle Islands, and the open lake) differing in bathymetry and limnological and biological patterns. <span class="hlt">Zooplankton</span> abundance was three times higher in the Duluth-Superior and Apostle Islands regions than in the open lake due to the large numbers of rotifers. Copepods were far more abundant than Cladocera in all ecoregions. Mean <span class="hlt">zooplankton</span> size was larger in the open lake due to dominance by large calanoid copepods although size of individual taxa was similar among ecoregions. Forage fish abundance and biomass was highest in the Apostle Islands region and lowest in the open lake ecoregion. Lake herring (Coregonus artedi), rainbow smelt (Osmerus mordax) and deepwater ciscoes (Coregonus spp.) comprised over 90% of the abundance and biomass of fishes caught in midwater trawls and recorded with hydroacoustics. Growth and condition of fish was good, suggesting they were not resource limited. Fish and <span class="hlt">zooplankton</span> assemblages differed among the three ecoregions of western Lake Superior, due to a combination of physical and limnological factors related to bathymetry and landscape position.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Ocgy...58..205K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Ocgy...58..205K"><span>Species Composition and Distribution of <span class="hlt">Zooplankton</span> from Northeastern Sakhalin Shelf (Sea of Okhotsk)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasyan, V. V.</p> <p>2018-03-01</p> <p>The species composition, density, biomass, and distribution of <span class="hlt">zooplankton</span> of the northeastern Sakhalin shelf, Sea of Okhotsk (Chaivo, Pil'tunskii, and Morskoi regions) were studied in October 2014. <span class="hlt">Zooplankton</span> was represented by 15 taxonomic groups, which were dominated by Copepoda (13 species). The average density and biomass was highest in the Chaivo region (14112 ± 4322 ind./m3, 395 ± 107 mg/m3) and in the Pil'tunskii region (16692 ± 10707 ind./m3, 346 ± 233 mg/m3); the abundance of detected taxonomic groups was minimal (8-12). The average density and biomass of <span class="hlt">zooplankton</span> was up to 4304 ± 2441 ind./m3, 133 ± 77 mg/m3 in the Morskoi region and increased with depth; the abundance of taxa was maximum (15). Four species of copepods made up the majority of the density and biomass of <span class="hlt">zooplankton</span>: Acartia hudsonica, Eurytemora herdmani, Pseudocalanus newmani, and Oithona similis. In the Chaivo region, species of the genera Acartia, Eurytemora, and Oithona dominated and subdominated; in Pil'tunskii region, species of the genera Acartia and Oithona dominated and subdominated; and in the Morskoi region, species of the genera Oithona, Pseudocalanus, and Acartia dominated and subdominated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61267&keyword=copepod&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61267&keyword=copepod&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>SIMULATING TEMPORAL VARIATIONS IN NUTRIENT, PHYTOPLANKTON, AND <span class="hlt">ZOOPLANKTON</span> ON THE INNER OREGON SHELF</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The objective of this study is to use a numerical model to examine the linkages between physical processes and temporal variability in the plankton dynamics in a coastal upwelling system. We used a nutrient-phytoplankton-<span class="hlt">zooplankton</span> model coupled to a two-dimensional circulation...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000JMS....24..355K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000JMS....24..355K"><span>A review of <span class="hlt">zooplankton</span> investigations of the Black Sea over the last decade</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kideys, Ahmet E.; Kovalev, Alexander V.; Shulman, Gregory; Gordina, Anna; Bingel, Ferit</p> <p>2000-03-01</p> <p>Investigations performed in the last decade indicate that there have been important changes in the <span class="hlt">zooplankton</span> composition and structure in the Black Sea. However, contrasting events taking place in different regions of the Black Sea indicate a non-uniform structure of its ecosystem. Several fodder <span class="hlt">zooplankton</span> species have either disappeared from or substantially decreased in number at different sampling sites of the Black Sea over the last one or two decades. Some other species adapted to thrive in eutrophic conditions have either appeared or increased in quantity. Meanwhile the biomass of the fodder <span class="hlt">zooplankton</span> has also fluctuated considerably through the years. However, there seems to be a reverse trend in the long-term variation of fodder <span class="hlt">zooplankton</span> between the shallow western and deep eastern areas. Over the last few decades the abundance of fish larvae has decreased significantly when compared either to past records or with larval abundances of other seas. This was shown to be due mainly to malnutrition of larvae. One of the most striking changes in the ichthyoplankton has been the shift in the spawning areas of the main fish species, the anchovy Engraulis encrasicolus from the northwestern to the southeastern Black Sea. Even the invading ctenophore Mnemiopsis were found to be starving. The condition of other species ( Calanus euxinus and Pleurobrachia pileus) disclosed the fact that cyclonic regions where chlorophyll and nutrient concentrations are high, provide better nutrition than anticyclonic regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME14E0667M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME14E0667M"><span>Metagenetic Sequencing of <span class="hlt">Zooplankton</span> Communities in the High-Diversity Central North Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matthews, S. A.; van Woudenberg, L.; Iacchei, M.; Lenz, P. H.; Goetze, E.</p> <p>2016-02-01</p> <p>Marine <span class="hlt">zooplankton</span> are important intermediate trophic level consumers in the ocean, and the subtropical North Pacific holds global maxima in species diversity for these communities. <span class="hlt">Zooplankton</span> assemblages in this region include several species complexes, with many understudied and morphologically cryptic species. We used metagenetic sequencing to characterize <span class="hlt">zooplankton</span> community composition across depth (0-1500m) at an open ocean time series site in the central North Pacific (Station ALOHA), using depth-stratified 1m2 MOCNESS samples that were size fractionated into 5 size classes (0.2-0.5 mm, 0.5-1 mm, 1-2 mm, 2-5 mm, >5 mm). Our goals were to quantify the fraction of the community that is currently undescribed, identify taxonomic groups that contain large numbers of undescribed species and may be important to biogeochemical cycling in the ocean, and establish a metagenetic method that can be used to effectively characterize the species richness of epipelagic and mesopelagic communities in this region. Amplicons from several DNA loci, including mitochondrial cytochrome c oxidase subunit I and 12S rRNA, and nuclear 18S and 28S rRNA genes were sequenced on the MiSeq Illumina platform to characterize community composition. We evaluate species composition across metagenetic marker regions, pelagic depth zones, day and night-time MOCNESS tows, and compare our findings with prior species lists from the region. Our results are an important contribution to establishing standardized metagenetic methods for marine <span class="hlt">zooplankton</span> communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19852074','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19852074"><span>Trace metal dynamics in <span class="hlt">zooplankton</span> from the Bay of Bengal during summer monsoon.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rejomon, G; Kumar, P K Dinesh; Nair, M; Muraleedharan, K R</p> <p>2010-12-01</p> <p>Trace metal (Fe, Co, Ni, Cu, Zn, Cd, and Pb) concentrations in <span class="hlt">zooplankton</span> from the mixed layer were investigated at 8 coastal and 20 offshore stations in the western Bay of Bengal during the summer monsoon of 2003. The ecotoxicological importance of trace metal uptake was apparent within the Bay of Bengal <span class="hlt">zooplankton</span>. There was a distinct spatial heterogeneity of metals, with highest concentrations in the upwelling zones of the southeast coast, moderate concentrations in the cyclonic eddy of the northeast coast, and lowest concentrations in the open ocean warm gyre regions. The average trace metal concentrations (μg g⁻¹) in coastal <span class="hlt">zooplankton</span> (Fe, 44894.1 ± 12198.2; Co, 46.2 ± 4.6; Ni, 62.8 ± 6.5; Cu, 84.9 ± 6.7; Zn, 7546.8 ± 1051.7; Cd, 46.2 ± 5.6; Pb, 19.2 ± 2.6) were higher than in offshore <span class="hlt">zooplankton</span> (Fe, 3423.4 ± 681.6; Co, 19.5 ± 3.81; Ni, 25.3 ± 7.3; Cu, 29.4 ± 4.2; Zn, 502.3 ± 124.3; Cd, 14.3 ± 2.9; Pb, 3.2 ± 2.0). A comparison of average trace metal concentrations in <span class="hlt">zooplankton</span> from the Bay of Bengal showed enrichment of Fe, Co, Ni, Cu, Zn, Cd, and Pb in coastal <span class="hlt">zooplankton</span> may be related to metal absorption from primary producers, and differences in metal concentrations in phytoplankton from coastal waters (upwelling zone and cyclonic eddy) compared with offshore waters (warm gyre). <span class="hlt">Zooplankton</span> showed a great capacity for accumulations of trace metals, with average concentration factors of 4 867 929 ± 569 971, 246 757 ± 51 321, 337 180 ± 125 725, 43 480 ± 11 212, 1 046 371 ± 110 286, 601 679 ± 213 949, and 15 420 ± 9201 for Fe, Co, Ni, Cu, Zn, Cd, and Pb with respect to dissolved concentrations in coastal and offshore waters of the Bay of Bengal. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2009. Copyright © 2009 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DSRI..126..103D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DSRI..126..103D"><span>Deep-water <span class="hlt">zooplankton</span> in the Mediterranean Sea: Results from a continuous, synchronous sampling over different regions using sediment traps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Danovaro, R.; Carugati, L.; Boldrin, A.; Calafat, A.; Canals, M.; Fabres, J.; Finlay, K.; Heussner, S.; Miserocchi, S.; Sanchez-Vidal, A.</p> <p>2017-08-01</p> <p>Information on the dynamics of deep-sea biota is extremely scant particularly for long-term time series on deep-sea <span class="hlt">zooplankton</span>. Here, we present the results of a deep-sea <span class="hlt">zooplankton</span> investigation over one annual cycle based on samples from sediment trap moorings in three sub-basins along the Mediterranean Sea. Deep-sea <span class="hlt">zooplankton</span> assemblages were dominated by copepods, as in shallow waters, only in the Adriatic Sea (>60% of total abundance), but not in the deep Ionian Sea, where ostracods represented >80%, neither in the deep Alboran Sea, where polychaetes were >70%. We found that deep-sea <span class="hlt">zooplankton</span> assemblages: i) are subjected to changes in their abundance and structure over time, ii) are characterized by different dominant taxa in different basins, and iii) display clear taxonomic segregation between shallow and near-bottom waters. <span class="hlt">Zooplankton</span> biodiversity decreases with increasing water depth, but the equitability increases. We suggest here that variations of <span class="hlt">zooplankton</span> abundance and assemblage structure are likely influenced by the trophic condition characterizing the basins. Our findings provide new insights on this largely unknown component of the deep ocean, and suggest that changes in the export of organic matter from the photic zone, such as those expected as a consequence of global change, can significantly influence <span class="hlt">zooplankton</span> assemblages in the largest biome on Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ECSS..198..400H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ECSS..198..400H"><span>Spatial patterns of littoral <span class="hlt">zooplankton</span> assemblages along a salinity gradient in a brackish sea: A functional diversity perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Helenius, Laura K.; Leskinen, Elina; Lehtonen, Hannu; Nurminen, Leena</p> <p>2017-11-01</p> <p>The distribution patterns and diversity of littoral <span class="hlt">zooplankton</span> are both key baseline information for understanding the functioning of coastal ecosystems, and for identifying the mechanisms by which the impacts of recently increased eutrophication are transferred through littoral food webs. In this study, <span class="hlt">zooplankton</span> community structure and diversity along a shallow coastal area of the northern Baltic Sea were determined in terms of horizontal environmental gradients. Spatial heterogeneity of the <span class="hlt">zooplankton</span> community was examined along the gradient. Altogether 31 sites in shallow sandy bays on the coast of southwest Finland were sampled in the summer periods of 2009 and 2010 for <span class="hlt">zooplankton</span> and environmental variables (surface water temperature, salinity, turbidity, wave exposure, macrophyte coverage, chlorophyll a and nutrients). <span class="hlt">Zooplankton</span> diversity was measured as both taxonomic as well as functional diversity, using trait-based classification of planktonic crustaceans. Salinity, and to a lesser extent turbidity and temperature, were found to be the main predictors of the spatial patterns and functional diversity of the <span class="hlt">zooplankton</span> community. Occurrence of cyclopoid copepods, as well as abundances of the calanoid copepod genus Acartia and the rotifer genus Keratella were found to be key factors in differentiating sites along the gradient. As far as we know, this is the first extensive study of functional diversity in Baltic Sea coastal <span class="hlt">zooplankton</span> communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19853879','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19853879"><span>Role of predation by <span class="hlt">zooplankton</span> in transport and fate of protozoan (oo)cysts in granular activated carbon filtration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bichai, Françoise; Barbeau, Benoit; Dullemont, Yolanda; Hijnen, Wim</p> <p>2010-02-01</p> <p>The significance of <span class="hlt">zooplankton</span> in the transport and fate of pathogenic organisms in drinking water is poorly understood, although many hints of the role of predation in the persistence of microorganisms through water treatment processes can be found in literature. The objective of this study was to assess the impact of predation by natural <span class="hlt">zooplankton</span> on the transport and fate of protozoan (oo)cysts in granular activated carbon (GAC) filtration process. UV-irradiated unlabelled Cryptosporidium parvum and Giardia lamblia (oo)cysts were seeded into two pilot-scale GAC filtration columns operated under full-scale conditions. In a two-week period after seeding, a reduction of free (oo)cysts retained in the filter bed was observed. <span class="hlt">Zooplankton</span> was isolated from the filter bed and effluent water on a 30 microm net before and during the two-week period after seeding; it was enumerated and identified. Rotifers, which are potential predators of (oo)cysts, accounted for the major part of the isolated <span class="hlt">zooplankton</span>. Analytical methods were developed to detect (oo)cysts internalized in natural <span class="hlt">zooplankton</span> isolated from the filter bed and effluent water. Sample sonication was optimized to disrupt <span class="hlt">zooplankton</span> organisms and release internalized microorganisms. (Oo)cysts released from <span class="hlt">zooplankton</span> after sonication were isolated by IMS and stained (EasyStain) for microscopic counting. Both Cryptosporidium and Giardia (oo)cysts were detected in association with <span class="hlt">zooplankton</span> in the filter bed samples as well as in the effluent of GAC filters. The results of this study suggest that predation by <span class="hlt">zooplankton</span> can play a role in the remobilization of persistent pathogens such as Cryptosporidium and Giardia (oo)cysts retained in GAC filter beds, and consequently in the transmission of these pathogens in drinking water. Copyright 2009 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010DSRI...57.1278W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010DSRI...57.1278W"><span>Feeding ecology of mesopelagic <span class="hlt">zooplankton</span> of the subtropical and subarctic North Pacific Ocean determined with fatty acid biomarkers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, S. E.; Steinberg, D. K.; Chu, F.-L. E.; Bishop, J. K. B.</p> <p>2010-10-01</p> <p>Mesopelagic <span class="hlt">zooplankton</span> may meet their nutritional and metabolic requirements in a number of ways including consumption of sinking particles, carnivory, and vertical migration. How these feeding modes change with depth or location, however, is poorly known. We analyzed fatty acid (FA) profiles to characterize <span class="hlt">zooplankton</span> diet and large particle (>51 μm) composition in the mesopelagic zone (base of euphotic zone -1000 m) at two contrasting time-series sites in the subarctic (station K2) and subtropical (station ALOHA) Pacific Ocean. Total FA concentration was 15.5 times higher in <span class="hlt">zooplankton</span> tissue at K2, largely due to FA storage by seasonal vertical migrators such as Neocalanus and Eucalanus. FA biomarkers specific to herbivory implied a higher plant-derived food source at mesotrophic K2 than at oligotrophic ALOHA. <span class="hlt">Zooplankton</span> FA biomarkers specific to dinoflagellates and diatoms indicated that diatoms, and to a lesser extent, dinoflagellates were important food sources at K2. At ALOHA, dinoflagellate FAs were more prominent. Bacteria-specific FA biomarkers in <span class="hlt">zooplankton</span> tissue were used as an indicator of particle feeding, and peaks were recorded at depths where known particle feeders were present at ALOHA (e.g., ostracods at 100-300 m). In contrast, depth profiles of bacterial FA were relatively constant with depth at K2. Diatom, dinoflagellate, and bacterial biomarkers were found in similar proportions in both <span class="hlt">zooplankton</span> and particles with depth at both locations, providing additional evidence that mesopelagic <span class="hlt">zooplankton</span> consume sinking particles. Carnivory indices were higher and increased significantly with depth at ALOHA, and exhibited distinct peaks at K2, representing an increase in dependence on other <span class="hlt">zooplankton</span> for food in deep waters. Our results indicate that feeding ecology changes with depth as well as by location. These changes in <span class="hlt">zooplankton</span> feeding ecology from the surface through the mesopelagic zone, and between contrasting environments</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70036228','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70036228"><span>The Lake Ontario <span class="hlt">zooplankton</span> community before (1987-1991) and after (2001-2005) invasion-induced ecosystem change</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stewart, T.J.; Johannsson, O.E.; Holeck, K.; Sprules, W.G.; O'Gorman, R.</p> <p>2010-01-01</p> <p>We assessed changes in Lake Ontario <span class="hlt">zooplankton</span> biomass, production, and community composition before (1987–1991) and after (2001–2005) invasion-induced ecosystem changes. The ecosystem changes were associated with establishment of invasive dreissenid mussels and invasive predatory cladocerans (Bythotrephes and Cercopagis). Whole-lake total epilimnetic plus metalimnetic <span class="hlt">zooplankton</span> production declined by approximately half from 42.45 (g dry wt∙m−2∙ year−1) during 1987–1991 to 21.91 (g dry wt∙m−2∙ year−1) in 2003 and averaged 21.01 (g dry wt∙m−2∙ year−1) during 2001–2005. Analysis of two independent data sets indicates that the mean biomass and biomass proportion of cyclopoid copepods declined while the same measures increased for the invasive predatory cladocerans. Changes in means and proportions of all other <span class="hlt">zooplankton</span> groups were not consistent between the data sets. Cyclopoid copepod biomass and production declined by factors ranging from 3.6 to 5.7. Invasive predatory cladoceran biomass averaged from 5.0% to 8.0% of the total <span class="hlt">zooplankton</span> biomass. The <span class="hlt">zooplankton</span> community was otherwise resilient to the invasion-induced disruption as <span class="hlt">zooplankton</span> species richness and diversity were unaffected. <span class="hlt">Zooplankton</span> production was likely reduced by declines in primary productivity but may have declined further due to increased predation by alewives and invasive predatory cladocerans. Shifts in <span class="hlt">zooplankton</span> community structure were consistent with increased predation pressure on cyclopoid copepods by alewives and invasive predatory cladocerans. Predicted declines in the proportion of small cladocerans were not evident. This study represents the first direct comparison of changes in Lake Ontario <span class="hlt">zooplankton</span> production before and after the invasion-induced disruption and will be important to food web-scale investigations of invasion effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29801208','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29801208"><span>Fate of thiamethoxam in mesocosms and response of the <span class="hlt">zooplankton</span> community.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lobson, C; Luong, K; Seburn, D; White, M; Hann, B; Prosser, R S; Wong, C S; Hanson, M L</p> <p>2018-05-14</p> <p>Thiamethoxam is a neonicotinoid insecticide that can reach wetlands in agro-ecosystems through runoff. The fate and effects of thiamethoxam on non-target organisms in shallow wetland ecosystems have not been well characterized. To this end, a mesocosm study was conducted with a focus on characterizing <span class="hlt">zooplankton</span> community responses. A single pulse application of thiamethoxam (0, 25, 50, 100, 250, and 500 μg/L; n = 3) was applied to experimental systems and monitored for 8 weeks. The mean half-life of thiamethoxam among the different treatments was 3.7 days in the water column with concentrations of <0.8 μg/L in the majority of mesocosms by 56 days. Principal response curve analysis did not show any significant concentration-dependent differences in the <span class="hlt">zooplankton</span> community among treatments over the course of the study. The minimum detectable difference (MDD%) values for abundance of potentially sensitive arthropod taxa (nauplius larvae, cyclopoid copepods) allowed the detections from controls as low as 42 and 59% effect, respectively. The MDD% values for total abundance of <span class="hlt">zooplankton</span> (including the potentially less sensitive taxonomic group of Rotifera) allowed the detection from controls as low as 41% effect. There were no statistically significant differences in <span class="hlt">zooplankton</span> abundance or diversity between control and treated mesocosms at the end of the study. There were also no statistically significant differences for individual taxa that were sustained between sampling points, or manifested as a concentration-response. We conclude that acute exposure to thiamethoxam at environmentally relevant concentrations (typically ng/L) likely does not represent a significant adverse ecological risk to wetland <span class="hlt">zooplankton</span> community abundance and structure. Copyright © 2018 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018CSR...160...49F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018CSR...160...49F"><span><span class="hlt">Zooplankton</span> seasonality across a latitudinal gradient in the Northeast Atlantic Shelves Province</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fanjul, Alvaro; Iriarte, Arantza; Villate, Fernando; Uriarte, Ibon; Atkinson, Angus; Cook, Kathryn</p> <p>2018-05-01</p> <p><span class="hlt">Zooplankton</span> seasonality and its environmental drivers were studied at four coastal sites within the Northeast Atlantic Shelves Province (Bilbao35 (B35) and Urdaibai35 (U35) in the Bay of Biscay, Plymouth L4 (L4) in the English Channel and Stonehaven (SH) in the North Sea) using time series spanning 1999-2013. Seasonal community patterns were extracted at the level of broad <span class="hlt">zooplankton</span> groups and copepod and cladoceran genera using redundancy analysis. Temperature was generally the environmental factor that explained most of the taxa seasonal variations at the four sites. However, between-site differences related to latitude and trophic status (i.e. from oligotrophic to mesotrophic) were observed in the seasonality of <span class="hlt">zooplankton</span> community, mainly in the pattern of taxa that peaked in spring-summer as opposed to late autumn-winter <span class="hlt">zooplankton</span>, which were linked primarily to differences in the seasonal pattern of phytoplankton. The percentage of taxa variations explained by environmental factors increased with latitude and trophic status likely related to the increase in the co-variation of temperature and chlorophyll a, as well as in the increase in regularity of the seasonal patterns of both temperature and chlorophyll a from south to north, and of chlorophyll a with trophic status. Cladocerans and cirripede larvae at B35 and U35, echinoderm larvae at L4 and decapod larvae at SH made the highest contribution to shape the main mode of seasonal pattern of <span class="hlt">zooplankton</span> community, which showed a seasonal delay with latitude, as well as with the increase in trophic status.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24551103','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24551103"><span>Spatio-temporal variability of the North Sea cod recruitment in relation to temperature and <span class="hlt">zooplankton</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nicolas, Delphine; Rochette, Sébastien; Llope, Marcos; Licandro, Priscilla</p> <p>2014-01-01</p> <p>The North Sea cod (Gadus morhua, L.) stock has continuously declined over the past four decades linked with overfishing and climate change. Changes in stock structure due to overfishing have made the stock largely dependent on its recruitment success, which greatly relies on environmental conditions. Here we focus on the spatio-temporal variability of cod recruitment in an effort to detect changes during the critical early life stages. Using International Bottom Trawl Survey (IBTS) data from 1974 to 2011, a major spatio-temporal change in the distribution of cod recruits was identified in the late 1990s, characterized by a pronounced decrease in the central and southeastern North Sea stock. Other minor spatial changes were also recorded in the mid-1980s and early 1990s. We tested whether the observed changes in recruits distribution could be related with direct (i.e. temperature) and/or indirect (i.e. changes in the quantity and quality of <span class="hlt">zooplankton</span> prey) effects of climate variability. The analyses were based on spatially-resolved time series, i.e. sea surface temperature (SST) from the Hadley Center and <span class="hlt">zooplankton</span> records from the Continuous Plankton Recorder Survey. We showed that spring SST increase was the main driver for the most recent decrease in cod recruitment. The late 1990s were also characterized by relatively low total <span class="hlt">zooplankton</span> biomass, particularly of energy-rich <span class="hlt">zooplankton</span> such as the copepod Calanus finmarchicus, which have further contributed to the decline of North Sea cod recruitment. Long-term spatially-resolved observations were used to produce regional distribution models that could further be used to predict the abundance of North Sea cod recruits based on temperature and <span class="hlt">zooplankton</span> food availability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004DSRII..51.2041L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004DSRII..51.2041L"><span>Acoustically-inferred <span class="hlt">zooplankton</span> distribution in relation to hydrography west of the Antarctic Peninsula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lawson, Gareth L.; Wiebe, Peter H.; Ashjian, Carin J.; Gallager, Scott M.; Davis, Cabell S.; Warren, Joseph D.</p> <p>2004-08-01</p> <p>The relationship between the distribution of <span class="hlt">zooplankton</span>, especially euphausiids ( Euphausia and Thysanoessa spp.), and hydrographic regimes of the Western Antarctic Peninsula continental shelf in and around Marguerite Bay was studied as part of the Southern Ocean GLOBEC program. Surveys were conducted from the RVIB N.B. Palmer in austral fall (April-June) and winter (July-August) of 2001. Acoustic, video, and environmental data were collected along 13 transect lines running across the shelf and perpendicular to the Western Antarctic Peninsula coastline, between 65°S and 70°S. Depth-stratified net tows conducted at selected locations provided ground-truthing for acoustic observations. In fall, acoustic volume backscattering strength at 120 kHz was greatest in the southern reaches of the survey area and inside Marguerite Bay, suggestive of high <span class="hlt">zooplankton</span> and micronekton biomass in these regions. Vertically, highest backscattering was in the 150-450 m depth range, associated with modified Circumpolar Deep Water (CDW). The two deep troughs that intersect the shelf break were characterized by reduced backscattering, similar to levels observed off-shelf and indicative of lower <span class="hlt">zooplankton</span> biomass in recent intrusions of CDW onto the continental shelf. Estimates of dynamic height suggested that geostrophic circulation likely caused both along- and across-shelf transport of <span class="hlt">zooplankton</span>. By winter, scattering had decreased by an order of magnitude (10 dB) in the upper 300 m of the water column in most areas, and high backscattering levels were found primarily in a deep (>300 m) scattering layer present close to the bottom. The seasonal decrease is potentially explained by advection of <span class="hlt">zooplankton</span>, vertical and horizontal movements, and mortality. Predictions of expected backscattering levels based on net samples suggested that large euphausiids were the dominant source of backscattering only at very particular locations and depths, and that copepods, siphonophores, and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011DSRII..58..699B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011DSRII..58..699B"><span>Analysis of southeast Australian <span class="hlt">zooplankton</span> observations of 1938-42 using synoptic oceanographic conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baird, Mark E.; Everett, Jason D.; Suthers, Iain M.</p> <p>2011-03-01</p> <p>The research vessel Warreen obtained 1742 planktonic samples along the continental shelf and slope of southeast Australia from 1938-42, representing the earliest spatially and temporally resolved <span class="hlt">zooplankton</span> data from Australian marine waters. In this paper, Warreen observations along the southeast Australian seaboard from 28°S to 38°S are interpreted based on synoptic meteorological and oceanographic conditions and ocean climatologies. Meteorological conditions are based on the NOAA-CIRES 20th Century Reanalysis Project; oceanographic conditions use Warreen hydrological observations, and the ocean climatology is the CSIRO Atlas of Regional Seas. The Warreen observations were undertaken in waters on average 0.45 °C cooler than the climatological average, and included the longest duration El Niño of the 20th century. In northern New South Wales (NSW), week time-scale events dominate <span class="hlt">zooplankton</span> response. In August 1940 an unusual winter upwelling event occurred in northern NSW driven by a stronger than average East Australian Current (EAC) and anomalous northerly winds that resulted in high salp and larvacean abundance. In January 1941 a strong upwelling event between 28° and 33°S resulted in a filament of upwelled water being advected south and alongshore, which was low in <span class="hlt">zooplankton</span> biovolume. In southern NSW a seasonal cycle in physical and planktonic characteristics is observed. In January 1941 the poleward extension of the EAC was strong, advecting more tropical tunicate species southward. <span class="hlt">Zooplankton</span> abundance and distribution on the continental shelf and slope are more dependent on weekly to monthly timescales on local oceanographic and meteorological conditions than continental-scale interannual trends. The interpretation of historical <span class="hlt">zooplankton</span> observations of the waters off southeast Australia for the purpose of quantifying anthropogenic impacts will be improved with the use of regional hindcasts of synoptic ocean and atmospheric weather that can</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3923776','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3923776"><span>Spatio-Temporal Variability of the North Sea Cod Recruitment in Relation to Temperature and <span class="hlt">Zooplankton</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nicolas, Delphine; Rochette, Sébastien; Llope, Marcos; Licandro, Priscilla</p> <p>2014-01-01</p> <p>The North Sea cod (Gadus morhua, L.) stock has continuously declined over the past four decades linked with overfishing and climate change. Changes in stock structure due to overfishing have made the stock largely dependent on its recruitment success, which greatly relies on environmental conditions. Here we focus on the spatio-temporal variability of cod recruitment in an effort to detect changes during the critical early life stages. Using International Bottom Trawl Survey (IBTS) data from 1974 to 2011, a major spatio-temporal change in the distribution of cod recruits was identified in the late 1990s, characterized by a pronounced decrease in the central and southeastern North Sea stock. Other minor spatial changes were also recorded in the mid-1980s and early 1990s. We tested whether the observed changes in recruits distribution could be related with direct (i.e. temperature) and/or indirect (i.e. changes in the quantity and quality of <span class="hlt">zooplankton</span> prey) effects of climate variability. The analyses were based on spatially-resolved time series, i.e. sea surface temperature (SST) from the Hadley Center and <span class="hlt">zooplankton</span> records from the Continuous Plankton Recorder Survey. We showed that spring SST increase was the main driver for the most recent decrease in cod recruitment. The late 1990s were also characterized by relatively low total <span class="hlt">zooplankton</span> biomass, particularly of energy-rich <span class="hlt">zooplankton</span> such as the copepod Calanus finmarchicus, which have further contributed to the decline of North Sea cod recruitment. Long-term spatially-resolved observations were used to produce regional distribution models that could further be used to predict the abundance of North Sea cod recruits based on temperature and <span class="hlt">zooplankton</span> food availability. PMID:24551103</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017BGeo...14.1039R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017BGeo...14.1039R"><span>Carbon balance of a <span class="hlt">grazed</span> savanna grassland ecosystem in South Africa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Räsänen, Matti; Aurela, Mika; Vakkari, Ville; Beukes, Johan P.; Tuovinen, Juha-Pekka; Van Zyl, Pieter G.; Josipovic, Miroslav; Venter, Andrew D.; Jaars, Kerneels; Siebert, Stefan J.; Laurila, Tuomas; Rinne, Janne; Laakso, Lauri</p> <p>2017-03-01</p> <p>Tropical savannas and grasslands are estimated to contribute significantly to the total primary production of all terrestrial vegetation. Large parts of African savannas and grasslands are used for agriculture and cattle <span class="hlt">grazing</span>, but the carbon flux data available from these areas are limited. This study explores carbon dioxide fluxes measured with the eddy covariance method for 3 years at a <span class="hlt">grazed</span> savanna grassland in Welgegund, South Africa. The tree cover around the measurement site, <span class="hlt">grazed</span> by cattle and sheep, was around 15 %. The night-time respiration was not significantly dependent on either soil moisture or soil temperature on a weekly temporal scale, whereas on an annual timescale higher respiration <span class="hlt">rates</span> were observed when soil temperatures were higher. The carbon dioxide balances of the years 2010-2011, 2011-2012 and 2012-2013 were -85 ± 16, 67 ± 20 and 139 ± 13 gC m-2 yr-1, respectively. The yearly variation was largely determined by the changes in the early wet season fluxes (September to November) and in the mid-growing season fluxes (December to January). Early rainfall enhanced the respiratory capacity of the ecosystem throughout the year, whereas during the mid-growing season high rainfall resulted in high carbon uptake.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSAH54A0106W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSAH54A0106W"><span>Calcium Carbonate Dissolution Above the Lysocline: Implications of Copepod <span class="hlt">Grazing</span> on Coccolithophores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>White, M. M.; Waller, J. D.; Lubelczyk, L.; Drapeau, D.; Bowler, B.; Wyeth, A.; Fields, D.; Balch, W. M.</p> <p>2016-02-01</p> <p>Copepod-coccolithophore predator-prey interactions are of great importance because they facilitate the export of particulate inorganic and organic carbon (PIC and POC) from the surface ocean. Coccolith dissolution in acidic copepod guts has been proposed as a possible explanation for the paradox of PIC dissolution above the lysocline, but warrants further investigation. Using a new application of the 14C-microdiffusion technique, we investigated the dissolution of coccoliths in copepod guts. We considered both an estuarine predator-prey model (Acartia tonsa and Pleurochrysis carterae) and an open ocean predator-prey model (Calanus finmarchicus and Emiliania huxleyi). Additionally, we considered the impacts of pCO2 on this process to advance our understanding of the effects of ocean acidification on trophic interactions. In the estuarine predator-prey model, fecal pellets produced immediately after previously-starved copepods <span class="hlt">grazed</span> on P. carterae had PIC/POC ratios 27-40 % lower than that of the algae, indicating PIC dissolution within the copepod gut, with no impact of pCO2 on this dissolution. Subsequent fecal pellets showed increasing PIC/POC, suggesting that calcite dissolution decreases as the gut fills. The open ocean predator-prey model showed equivocal results, indicating high variability among individual <span class="hlt">grazing</span> behavior, and therefore no consistent impact of copepod <span class="hlt">grazing</span> on coccolith dissolution above the lysocline in the open ocean. We will further discuss the effects of fecal pellet PIC/POC ratios on sinking <span class="hlt">rate</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710414B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710414B"><span>Impact of cattle <span class="hlt">grazing</span> on soil and vegetation - a case study in a mountainous region of Austria</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bohner, Andreas; Foldal, Cecilie; Jandl, Robert</p> <p>2015-04-01</p> <p> phosphorus saturation was very high. Consequently, the risk of elevated nutrient losses via leaching and surface runoff is increased. This, in turn, may pose a threat to ground water, surface water and adjacent ecosystems. In the intensively <span class="hlt">grazed</span> cattle pasture we observed considerable changes in plant species composition and species cover. Vegetation cover, plant species richness, pasture yield, forage quality and below-ground phytomass declined due to overgrazing. In contrast, the untrampled and unmanured habitat below the fence of the paddock can be regarded as a retreat area for many plant species which do not tolerate heavy trampling and manuring. Thus, in assessing biodiversity, this corridor should be taken into consideration. Within the paddock, we found a permanent transfer of soil nutrients and organic matter by <span class="hlt">grazing</span> cattle, leading to a high spatial heterogeneity in some soil properties. Consequently, within intensively <span class="hlt">grazed</span> paddocks differential manure-application <span class="hlt">rates</span> and variations in <span class="hlt">grazing</span> intensity are necessary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25875617','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25875617"><span>De novo assembly and transcriptomic profiling of the <span class="hlt">grazing</span> response in Stipa grandis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wan, Dongli; Wan, Yongqing; Hou, Xiangyang; Ren, Weibo; Ding, Yong; Sa, Rula</p> <p>2015-01-01</p> <p>Stipa grandis (Poaceae) is one of the dominant species in a typical steppe of the Inner Mongolian Plateau. However, primarily due to heavy <span class="hlt">grazing</span>, the grasslands have become seriously degraded, and S. grandis has developed a special growth-inhibition phenotype against the stressful habitat. Because of the lack of transcriptomic and genomic information, the understanding of the molecular mechanisms underlying the <span class="hlt">grazing</span> response of S. grandis has been prohibited. Using the Illumina HiSeq 2000 platform, two libraries prepared from non-<span class="hlt">grazing</span> (FS) and overgrazing samples (OS) were sequenced. De novo assembly produced 94,674 unigenes, of which 65,047 unigenes had BLAST hits in the National Center for Biotechnology Information (NCBI) non-redundant (nr) database (E-value < 10-5). In total, 47,747, 26,156 and 40,842 unigenes were assigned to the Gene Ontology (GO), Clusters of Orthologous Group (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, respectively. A total of 13,221 unigenes showed significant differences in expression under the overgrazing condition, with a threshold false discovery <span class="hlt">rate</span> ≤ 0.001 and an absolute value of log2Ratio ≥ 1. These differentially expressed genes (DEGs) were assigned to 43,257 GO terms and were significantly enriched in 32 KEGG pathways (q-value ≤ 0.05). The alterations in the wound-, drought- and defense-related genes indicate that stressors have an additive effect on the growth inhibition of this species. This first large-scale transcriptome study will provide important information for further gene expression and functional genomics studies, and it facilitated our investigation of the molecular mechanisms of the S. grandis <span class="hlt">grazing</span> response and the associated morphological and physiological characteristics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4395228','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4395228"><span>De novo Assembly and Transcriptomic Profiling of the <span class="hlt">Grazing</span> Response in Stipa grandis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hou, Xiangyang; Ren, Weibo; Ding, Yong; Sa, Rula</p> <p>2015-01-01</p> <p>Background Stipa grandis (Poaceae) is one of the dominant species in a