Increased sporulation of vesicular-arbuscular mycorrhizal fungi by manipulation of nutrient regimens.

PubMed

Douds, D D; Schenck, N C

1990-02-01

Adjustment of pot culture nutrient solutions increased root colonization and sporulation of vesicular-arbuscular mycorrhizal (VAM) fungi. Paspalum notatum Flugge and VAM fungi were grown in a sandy soil low in N and available P. Hoagland nutrient solution without P enhanced sporulation in soil and root colonization of Acaulospora longula, Scutellospora heterogama, Gigaspora margarita, and a wide range of other VAM fungi over levels produced by a tap water control or nutrient solutions containing P. However, Glomus intraradices produced significantly more spores in plant roots in the tap water control treatment. The effect of the nutrient solutions was not due solely to N nutrition, because the addition of NH(4)NO(3) decreased both colonization and sporulation by G. margarita relative to levels produced by Hoagland solution without P.

Nutrient Regulation by Continuous Feeding Removes Limitations on Cell Yield in the Large-Scale Expansion of Mammalian Cell Spheroids

PubMed Central

Weegman, Bradley P.; Nash, Peter; Carlson, Alexandra L.; Voltzke, Kristin J.; Geng, Zhaohui; Jahani, Marjan; Becker, Benjamin B.; Papas, Klearchos K.; Firpo, Meri T.

2013-01-01

Cellular therapies are emerging as a standard approach for the treatment of several diseases. However, realizing the promise of cellular therapies across the full range of treatable disorders will require large-scale, controlled, reproducible culture methods. Bioreactor systems offer the scale-up and monitoring needed, but standard stirred bioreactor cultures do not allow for the real-time regulation of key nutrients in the medium. In this study, β-TC6 insulinoma cells were aggregated and cultured for 3 weeks as a model of manufacturing a mammalian cell product. Cell expansion rates and medium nutrient levels were compared in static, stirred suspension bioreactors (SSB), and continuously fed (CF) SSB. While SSB cultures facilitated increased culture volumes, no increase in cell yields were observed, partly due to limitations in key nutrients, which were consumed by the cultures between feedings, such as glucose. Even when glucose levels were increased to prevent depletion between feedings, dramatic fluctuations in glucose levels were observed. Continuous feeding eliminated fluctuations and improved cell expansion when compared with both static and SSB culture methods. Further improvements in growth rates were observed after adjusting the feed rate based on calculated nutrient depletion, which maintained physiological glucose levels for the duration of the expansion. Adjusting the feed rate in a continuous medium replacement system can maintain the consistent nutrient levels required for the large-scale application of many cell products. Continuously fed bioreactor systems combined with nutrient regulation can be used to improve the yield and reproducibility of mammalian cells for biological products and cellular therapies and will facilitate the translation of cell culture from the research lab to clinical applications. PMID:24204645

Lake level fluctuations boost toxic cyanobacterial "oligotrophic blooms".

PubMed

Callieri, Cristiana; Bertoni, Roberto; Contesini, Mario; Bertoni, Filippo

2014-01-01

Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena), a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D. lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D. lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms.

Red Maple (Acer rubrum L.) Growth and Foliar Nutrient Responses to Soil Fertility Level and Water Regime

Treesearch

C. H. Pham; Howard G. Halverson; Gordon M. Heisler

1978-01-01

Red maple (Acer rubrum L.) seedlings were grown in a greenhouse using three treatments: two soil horizons, two soil moisture regimes, and three nutrient levels. Fertilization increased growth under moist conditions on the more fertile topsoil. Under dry conditions, fertilization had no effect on growth in subsoil, and slightly increased growth in...

Timber-harvest clearcutting and nutrients in the Northeastern United States

Treesearch

K. G. Reinhart

1973-01-01

The effect of ecosystem disturbance on nutrients in the system has been receiving widespread attention. An appraisal of research results in the Northeast indicates that timber-harvest clearcutting has not increased nutrient levels sufficiently to reduce water quality below drinking water standards. Losses of nutrients from clearcuttings in New Hampshire over a 2-year...

Nutrient profiling can help identify foods of good nutritional quality for their price: a validation study with linear programming.

PubMed

Maillot, Matthieu; Ferguson, Elaine L; Drewnowski, Adam; Darmon, Nicole

2008-06-01

Nutrient profiling ranks foods based on their nutrient content. They may help identify foods with a good nutritional quality for their price. This hypothesis was tested using diet modeling with linear programming. Analyses were undertaken using food intake data from the nationally representative French INCA (enquête Individuelle et Nationale sur les Consommations Alimentaires) survey and its associated food composition and price database. For each food, a nutrient profile score was defined as the ratio between the previously published nutrient density score (NDS) and the limited nutrient score (LIM); a nutritional quality for price indicator was developed and calculated from the relationship between its NDS:LIM and energy cost (in euro/100 kcal). We developed linear programming models to design diets that fulfilled increasing levels of nutritional constraints at a minimal cost. The median NDS:LIM values of foods selected in modeled diets increased as the levels of nutritional constraints increased (P = 0.005). In addition, the proportion of foods with a good nutritional quality for price indicator was higher (P < 0.0001) among foods selected (81%) than among foods not selected (39%) in modeled diets. This agreement between the linear programming and the nutrient profiling approaches indicates that nutrient profiling can help identify foods of good nutritional quality for their price. Linear programming is a useful tool for testing nutrient profiling systems and validating the concept of nutrient profiling.

Predicting nutrient and sediment loadings to streams from landscape metrics: A multiple watershed study from the United States Mid-Atlantic Region

Treesearch

K. Bruce Jones; Anne C. Neale; Malisha S. Nash; Rick D. van Remortel; James D. Wickham; Kurt H. Riitters; Robert V. O' Neill

2001-01-01

There has been an increasing interest in evaluating the relative condition or health of water resources at regional and national scales. Of particular interest is an ability to identify those areas where surface and ground waters have the greatest potential for high levels of nutrient and sediment loadings. High levels of nutrient and sediment loadings can have adverse...

Differential Effect of Irradiance and Nutrient Nitrate on the Relationship of in Vivo and in Vitro Nitrate Reductase Assay in Chlorophyllous Tissues 1

PubMed Central

Jones, Richard Wyn; Sheard, Robert W.

1977-01-01

Growth at increasing continuous irradiance (at high nutrient nitrate) and nutrient nitrate concentrations (at high continuous irradiance) furnished increases in the in vivo and in vitro nitrate reductase activities of corn (Zea mays L.), field peas (Pisum arvense L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and globe amaranth (Gomphrena globosa L.) leaves and of marrow (Cucurbita pepo L.) cotyledons. Ratios of in vivo to in vitro activity declined exponentially in all species with increasing nitrate reductase levels promoted by nutrient nitrate. The ratios were more nearly independent of nitrate reductase levels generated by adjusting the irradiance; major exceptions were marrow and wheat at low (1.5 klux and less) irradiances and peas throughout the irradiance range, where decreases in the ratio were accompanied by increases in in situ nitrate concentration. The ratio also increased at the highest irradiance (39.2 klux) in wheat and barley, associated with a decline of in vitro nitrate reductase. These differences in response to irradiance and nutrient nitrate indicate that the in vivo assay does not provide a simple measure of nitrate reductase but rather yields a more composite measure of nitrate reduction, possibly related both to nitrate reductase level and to the supply of reductant for in vivo activity. PMID:16659888

Simulated global change: contrasting short and medium term growth and reproductive responses of a common alpine/Arctic cushion plant to experimental warming and nutrient enhancement.

PubMed

Alatalo, Juha M; Little, Chelsea J

2014-01-01

Cushion plants are important components of alpine and Arctic plant communities around the world. They fulfill important roles as facilitators, nurse plants and foundation species across trophic levels for vascular plants, arthropods and soil microorganisms, the importance of these functions increasing with the relative severity of the environment. Here we report results from one of the few experimental studies simulating global change impacts on cushion plants; a factorial experiment with warming and nutrient enhancement that was applied to an alpine population of the common nurse plant, Silene acaulis, in sub-arctic Sweden. Experimental perturbations had significant short-term impacts on both stem elongation and leaf length. S. acaulis responded quickly by increasing stem elongation and (to a lesser extent) leaf length in the warming, nutrient, and the combined warming and nutrient enhancements. Cover and biomass also initially increased in response to the perturbations. However, after the initial positive short-term responses, S. acaulis cover declined in the manipulations, with the nutrient and combined warming and nutrient treatments having largest negative impact. No clear patterns were found for fruit production. Our results show that S. acaulis living in harsh environments has potential to react quickly when experiencing years with favorable conditions, and is more responsive to nutrient enhancement than to warming in terms of vegetative growth. While these conditions have an initial positive impact, populations experiencing longer-term increased nutrient levels will likely be negatively affected.

The Interplay Between Predation, Competition, and Nutrient Levels Influences the Survival of Escherichia coli in Aquatic Environments.

PubMed

Wanjugi, P; Fox, G A; Harwood, V J

2016-10-01

Nutrient levels, competition from autochthonous microorganisms, and protozoan predation may all influence survival of fecal microorganisms as they transition from the gastrointestinal tract to aquatic habitats. Although Escherichia coli is an important indicator of waterborne pathogens, the effects of environmental stressors on its survival in aquatic environments remain poorly understood. We manipulated organic nutrient, predation, and competition levels in outdoor microcosms containing natural river water, sediments, and microbial populations to determine their relative contribution to E. coli survival. The activities of predator (protozoa) and competitor (indigenous bacteria) populations were inhibited by adding cycloheximide or kanamycin. We developed a statistical model of E. coli density over time that fits with the data under all experimental conditions. Predation and competition had significant negative effects on E. coli survival, while higher nutrient levels increased survival. Among the main effects, predation accounted for the greatest variation (40 %) compared with nutrients (25 %) or competition (15 %). The highest nutrient level mitigated the effect of predation on E. coli survival. Thus, elevated organic nutrients may disproportionately enhance the survival of E. coli, and potentially that of other enteric bacteria, in aquatic habitats.

ESTUARINE-OCEAN EXCHANGE IN A NORTH PACIFIC ESTUARY: COMPARISON OF STEADY STATE AND DYNAMIC MODELS

EPA Science Inventory

Nutrient levels in coastal waters must be accurately assessed to determine the nutrient effects of increasing populations on coastal ecosystems. To accomplish this goal, in-field data with sufficient temporal resolution are required to define nutrient sources and sinks, and to ul...

ESTIMATING NITROGEN AND TIDAL EXCHANGE IN A NORTH PACIFIC ESTUARY WITH EPA'S VISUAL PLUMES PDSW MODEL

EPA Science Inventory

Accurate assessments of nutrient levels in coastal waters are required to determine the nutrient effects of increasing population pressure on coastal ecosystems. To accomplish this goal, in-field data with sufficient temporal resolution are required to define nutrient sources an...

ESTIMATING NITROGEN AND TIDAL EXCHANGE IN A NORTH PACIFIC ESTUARY WITH EPA'S VISUAL PLUMES PDSW MODEL

EPA Science Inventory

Accurate assessments of nutrient levels in coastal waters are required to determine the nutrient effects of increasing population pressure on coastal ecosystems. To accomplish this goal, in-field data with sufficient temporal resolution are required to define nutrient sources and...

Effect of Dietary Nutrient Density on Small Intestinal Phosphate Transport and Bone Mineralization of Broilers during the Growing Period.

PubMed

Li, Jianhui; Yuan, Jianmin; Miao, Zhiqiang; Song, Zhigang; Yang, Yu; Tian, Wenxia; Guo, Yuming

2016-01-01

A 2 × 4 factorial experiment was conducted to determine the effects of dietary nutrient density on growth performance, small intestinal epithelial phosphate transporter expression, and bone mineralization of broiler chicks fed with diets with different nutrient densities and nonphytate phosphorus (NPP) levels. The broilers were fed with the same starter diets from 0 to 21 days of age. In the grower phase (day 22 to 42), the broilers were randomly divided into eight groups according to body weight. Relatively high dietary nutrient density (HDND) and low dietary nutrient density (LDND) diets were assigned metabolic energy (ME) values of 3,150 and 2,950 kcal/kg, respectively. Crude protein and essential amino acid levels were maintained in the same proportion as ME to prepare the two diet types. NPP levels were 0.25%, 0.30%, 0.35%, and 0.40% of the diets. Results showed that a HDND diet significantly increased the body weight gain (BWG) of broilers and significantly decreased the feed conversion ratio and NPP consumed per BWG. HDND significantly decreased tibial P content of the broilers. Conversely, mRNA expression of NaPi-IIb and protein expression of calbindin were significantly increased in the intestine of broilers fed a HDND diet. HDND also increased vitamin D receptor (VDR) expression, especially at a relatively low dietary NPP level (0.25%). The mRNA expression of NaPi-IIa in the kidneys was significantly increased at a relatively low dietary NPP level (0.25%) to maintain P balance. Tibial P, calcium, and ash content were significantly decreased, as were calbindin and VDR expression levels in the intestine at a low NPP level. Therefore, HDND improved the growth rate of broilers and increased the expression of phosphate and calcium transporter in the small intestine, but adversely affected bone mineralization.

Cyclic and secular variation in microfossil biomineralization: clues to the biogeochemical evolution of Phanerozoic oceans

NASA Astrophysics Data System (ADS)

Martin, Ronald E.

1995-06-01

The stratigraphic occurrence and mineralogy of major protistan microfossil taxa tend to reflect evolutionary innovation in response to ocean chemistry and fertility. In foraminefera, the characteristic test composition—and, in some cases, ultrastructure—of each suborder is indicative of the degree of surface ocean CaCO 3 saturation, which varied in a cyclic manner through the Phanerozoic, at the time of origin of the suborder. High dissolved phosphate and low CaCO 3 saturation in late Precambrian-Early Cambrian surface waters may have prevented calcification in primitive non-calcareous (organic, agglutinated) foraminiferal stocks. Scattered reports of coccolithophorid-like microfossils from the Paleozoic are indicative of a secular trend in rising nutrient levels and marine productivity that controlled the initiation of calcareous oozes. Based on acritarch, carbon isotope, and phosphorite records, extremely low nutrient levels ("superligotrophic" conditions) in Cambrian-to-Devonian seas typically limited population densities of calcareous nannoplankton and prevented the formation of calcareous oozes. The overall "superoligotrophic" surface conditions of the Paleozoic were punctuated, though, by episodes of "catastrophic" eutrophication in the Late Ordovician, Late Devonia, and Late Carboniferous (Worsley et al., 1986). Following each episode, CaCO 3 rain rates were presumably enhanced because Marine C:P (MCP) burial ratios increased permanently above previous levels (Worsley et al., 1986). Nevertheless, it was not until the Carboniferous that the CCD had deepened sufficiently (via erosion of cratonic limestones) to allow pelagic calcareous oozes to begin to accumulate. Prior to this time, surface waters appear to have been sufficiently corrosive (high atmospheric pCO 2 and low CaCO 3 saturation), and the CCD sufficiently shallow, to dissolve virtually all incipient calcareous nannofossils. Following Late Permian extinctions, plankton re-expanded in response to both eustatic sea level rise (increased habitat availability) and increased nutrient levels ("mesotrophic" conditions). As organic matter (C org) and CaCO 3 rain rates increased, bioturbation rates also increased, thereby recycling nutrients back to the surface and accentuating productivity and calcareous ooze formation. MCP episodes further accelerated nutrient cycling and productivity in the Neogene, as indicated by the expansion of diatoms, which prefer nutrient-rich ("eutrophic") conditions. Ironically, while permanently increasing C:P burial ratios and productivity through the Phanerozoic, catastrophic fluctuations in nutrient levels may have also exacerbated mass extinctions via shortening of pelagic food chains. Nevertheless, re-expansion of the marine biosphere following each extinction episode resulted in a secular trend of increasing biomass and biotic diversity that may have contributed to the decline in background extinction rates through the Phanerozoic.

Effects of agricultural subsidies of nutrients and detritus on fish and plankton of shallow-reservoir ecosystems.

PubMed

Pilati, Alberto; Vanni, Michael J; González, María J; Gaulke, Alicia K

2009-06-01

Agricultural activities increase exports of nutrients and sediments to lakes, with multiple potential impacts on recipient ecosystems. Nutrient inputs enhance phytoplankton and upper trophic levels, and sediment inputs can shade phytoplankton, interfere with feeding of consumers, and degrade benthic habitats. Allochthonous sediments are also a potential food source for detritivores, as is sedimenting autochthonous phytodetritus, the production of which is stimulated by nutrient inputs. We examined effects of allochthonous nutrient and sediment subsidies on fish and plankton, with special emphasis on gizzard shad (Dorosoma cepedianum). This widespread and abundant omnivorous fish has many impacts on reservoir ecosystems, including negative effects on water quality via nutrient cycling and on fisheries via competition with sportfish. Gizzard shad are most abundant in agriculturally impacted, eutrophic systems; thus, agricultural subsidies may affect reservoir food webs directly and by enhancing gizzard shad biomass. We simulated agricultural subsidies of nutrients and sediment detritus by manipulating dissolved nutrients and allochthonous detritus in a 2 x 2 factorial design in experimental ponds. Addition of nutrients alone increased primary production and biomass of zooplanktivorous fish (bluegill and young-of-year gizzard shad). Addition of allochthonous sediments alone increased algal sedimentation and decreased seston and sediment C:P ratios. Ponds receiving both nutrients and sediments showed highest levels of phytoplankton and total phosphorus. Adult and juvenile gizzard shad biomass was enhanced equally by nutrient or sediment addition, probably because this apparently P-limited detritivore ingested similar amounts of P in all subsidy treatments. Nutrient excretion rates of gizzard shad were higher in ponds with nutrient additions, where sediments were composed mainly of phytodetritus. Therefore, gizzard shad can magnify the direct effects of nutrient subsidies on phytoplankton production, and these multiple effects must be considered in strategies to manage eutrophication and fisheries in warmwater reservoir lakes where gizzard shad can dominate fish biomass.

Interactive Effects of Nutrient and Mechanical Stresses on Plant Morphology

PubMed Central

Puijalon, Sara; Lena, Jean-Paul; Bornette, Gudrun

2007-01-01

Background and Aims Plant species frequently encounter multiple stresses under natural conditions, and the way they cope with these stresses is a major determinant of their ecological breadth. The way mechanical (e.g. wind, current) and resource stresses act simultaneously on plant morphological traits has been poorly addressed, even if both stresses often interact. This paper aims to assess whether hydraulic stress affects plant morphology in the same way at different nutrient levels. Methods An examination was made of morphological variations of an aquatic plant species growing under four hydraulic stress (flow velocity) gradients located in four habitats distributed along a nutrient gradient. Morphological traits covering plant size, dry mass allocation, organ water content and foliage architecture were measured. Key Results Significant interactive effects of flow velocity and nutrient level were observed for all morphological traits. In particular, increased flow velocity resulted in size reductions under low nutrient conditions, suggesting an adaptive response to flow stress (escape strategy). On the other hand, moderate increases in flow velocity resulted in increased size under high nutrient conditions, possibly related to an inevitable growth response to a higher nutrient supply induced by water renewal at the plant surface. For some traits (e.g. dry mass allocation), a consistent sense of variation as a result of increasing flow velocity was observed, but the amount of variation was either reduced or amplified under nutrient-rich compared with nutrient-poor conditions, depending on the traits considered. Conclusions These results suggest that, for a given species, a stress factor may result, in contrasting patterns and hence strategies, depending on a second stress factor. Such results emphasize the relevance of studies on plant responses to multiple stresses for understanding the actual ecological breadth of species. PMID:17913725

Short-term effect of nutrient availability and rainfall distribution on biomass production and leaf nutrient content of savanna tree species.

PubMed

Barbosa, Eduardo R M; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T; van Langevelde, Frank

2014-01-01

Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall) and nutrient availability (no fertilisation vs. fertilisation) affects seedlings' above-ground biomass production and leaf-nutrient concentrations (N, P and K) of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf nutrient concentration, our findings provide important insights that can help guide management plans that aim to preserve savanna biodiversity.

Elkhorn Slough: Detecting Eutrophication through Geospatial Modeling Applications

NASA Astrophysics Data System (ADS)

Caraballo Álvarez, I. O.; Childs, A.; Jurich, K.

2016-12-01

Elkhorn Slough in Monterey, California, has experienced substantial nutrient loading and eutrophication over the past 21 years as a result of fertilizer-rich runoff from nearby agricultural fields. This study seeks to identify and track spatial patterns of eutrophication hotspots and the correlation to land use changes, possible nutrient sources, and general climatic trends using remotely sensed and in situ data. Threats of rising sea level, subsiding marshes, and increased eutrophication hotspots demonstrate the necessity to analyze the effects of increasing nutrient loads, relative sea level changes, and sedimentation within Elkhorn Slough. The Soil & Water Assessment Tool (SWAT) model integrates specified inputs to assess nutrient and sediment loading and their sources. TerrSet's Land Change Modeler forecasts the future potential of land change transitions for various land cover classes around the slough as a result of nutrient loading, eutrophication, and increased sedimentation. TerrSet's Earth Trends Modeler provides a comprehensive analysis of image time series to rapidly assess long term eutrophication trends and detect spatial patterns of known hotspots. Results from this study will inform future coastal management practices and provide greater spatial and temporal insight into Elkhorn Slough eutrophication dynamics.

Interactive effects of nutrient additions and predation on infaunal communities

USGS Publications Warehouse

Posey, M.H.; Alphin, T.D.; Cahoon, L.; Lindquist, D.; Becker, M.E.

1999-01-01

Nutrient additions represent an important anthropogenic stress on coastal ecosystems. At moderate levels, increased nutrients may lead to increased primary production and, possibly, to increased biomass of consumers although complex trophic interactions may modify or mask these effects. We examined the influence of nutrient additions and interactive effects of trophic interactions (predation) on benthic infaunal composition and abundances through small-scale field experiments in 2 estuaries that differed in ambient nutrient conditions. A blocked experimental design was used that allowed an assessment of direct nutrient effects in the presence and absence of predation by epibenthic predators as well as an assessment of the independent effects of predation. Benthic microalgal production increased with experimental nutrient additions and was greater when infaunal abundances were lower, but there were no significant interactions between these factors. Increased abundances of one infaunal taxa, Laeonereis culveri, as well as the grazer feeding guild were observed with nutrient additions and a number of taxa exhibited higher abundances with predator exclusion. In contrast to results from freshwater systems there were no significant interactive effects between nutrient additions and predator exclusion as was predicted. The infaunal responses observed here emphasize the importance of both bottom-up (nutrient addition and primary producer driven) and top-down (predation) controls in structuring benthic communities. These processes may work at different spatial and temporal scales, and affect different taxa, making observation of potential interactive effects difficult.

Do shrubs reduce the adverse effects of grazing on soil properties?

USGS Publications Warehouse

Eldridge, David J.; Beecham, Genevieve; Grace, James B.

2015-01-01

Increases in the density of woody plants are a global phenomenon in drylands, and large aggregations of shrubs, in particular, are regarded as being indicative of dysfunctional ecosystems. There is increasing evidence that overgrazing by livestock reduces ecosystem functions in shrublands, but that shrubs may buffer the negative effects of increasing grazing. We examined changes in water infiltration and nutrient concentrations in soils under shrubs and in their interspaces in shrublands in eastern Australia that varied in the intensity of livestock grazing. We used structural equation modelling to test whether shrubs might reduce the negative effects of overgrazing on infiltration and soil carbon and nitrogen (henceforth ‘soil nutrients’). Soils under shrubs and subject to low levels of grazing were more stable and had greater levels of soil nutrients. Shrubs had a direct positive effect on soil nutrients; but, grazing negatively affected nutrients by increasing soil bulk density. Structural equation modelling showed that shrubs had a direct positive effect on water flow under ponded conditions but also enhanced water flow, indirectly, through increased litter cover. Any positive effects of shrubs on water flow under low levels of grazing waned at high levels of grazing. Our results indicate that shrubs may reduce the adverse effects of grazing on soil properties. Specifically, shrubs could restrict access to livestock and therefore protect soils and plants beneath their canopies. Low levels of grazing are likely to ensure the retention of soil water and soil carbon and nitrogen in shrubland soils.

Enhancement and inhibition of microbial activity in hydrocarbon- contaminated arctic soils: Implications for nutrient-amended bioremediation

USGS Publications Warehouse

Braddock, J.F.; Ruth, M.L.; Catterall, P.H.; Walworth, J.L.; McCarthy, K.A.

1997-01-01

Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) end low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus. When nutrients were added to soil in the field at three levels of N:P (100:45, 200:90, and 300:135 mg/kg soil), the greatest stimulation in microbial activity occurred at the lowest, rather than the highest, level of nutrient addition. The total soil-water potentials ranged from -2 to -15 bar with increasing levels of fertilizer. Semivolatile hydrocarbon concentrations declined significantly only in the soils treated at the low fertilizer level. These results indicate that an understanding of nutrient effects at a specific site is essential for successful bioremediation.Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) and low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus. When nutrients were added to soil in the field at three levels of N:P (100:45, 200:90, and 300:135 mg/kg soil), the greatest stimulation in microbial activity occurred at the lowest, rather than the highest, level of nutrient addition. The total soil-water potentials ranged from -2 to -15 bar with increasing levels of fertilizer. Semi-volatile hydrocarbon concentrations declined significantly only in the soils treated at the low fertilizer level. These results indicate that an understanding of nutrient effects at a specific site is essential for successful bioremediation.

Evaluating confidence in the impact of regulatory nutrient reduction and assessing the competing impact of climate change

NASA Astrophysics Data System (ADS)

Irby, I.; Friedrichs, M. A. M.

2017-12-01

Human impacts on the Chesapeake Bay through increased nutrient run-off as a result of land-use change, urbanization, and industrialization, have resulted in a degradation of water quality over the last half-century. These direct impacts, compounded with human-induced climate changes such as warming, rising sea level, and changes in precipitation, have elevated the conversation surrounding the future of the Bay's water quality. As a result, in 2010, a Total Maximum Daily Load (TMDL) was established for the Chesapeake Bay that limited nutrient and sediment input in an effort to increase dissolved oxygen. This research utilizes a multiple model approach to evaluate confidence in the estuarine water quality modeling portion of the TMDL. One of the models is then used to assess the potential impact climate change may have on the success of currently mandated nutrient reduction levels in 2050. Results demonstrate that although the models examined differ structurally and in biogeochemical complexity, they project a similar attainment of regulatory water quality standards after nutrient reduction, while also establishing that meeting water quality standards is relatively independent of hydrologic conditions. By developing a Confidence Index, this research identifies the locations and causes of greatest uncertainty in modeled projections of water quality. Although there are specific locations and times where the models disagree, this research lends an increased degree of confidence in the appropriateness of the TMDL levels and in the general impact nutrient reductions will have on Chesapeake Bay water quality under current environmental conditions. However, when examining the potential impacts of climate change, this research shows that the combined impacts of increasing temperature, sea level, and river flow negatively affect dissolved oxygen throughout the Chesapeake Bay and impact progress towards meeting the water quality standards associated with the TMDL with increased temperature as the primary culprit. These results, having been continually shared with the regulatory TMDL modelers, will aid in the decision making for the 2017 TMDL Mid-Point Assessment.

Long-term Nutrient Fertilization Increases CO2 Loss in Arctic Tundra

NASA Astrophysics Data System (ADS)

Graham, L. M.; Natali, S.; Rastetter, E. B.; Shaver, G. R.; Risk, D. A.; Loranty, M. M.; Jastrow, J. D.

2015-12-01

As anthropogenic climate change warms the Arctic, organic carbon (C) trapped in permafrost is at an increased risk of being released to the atmosphere as carbon dioxide (CO2). At the same time, higher rates of decomposition may increase nutrient availability and enhance plant growth, leading to an uptake of C that may offset respiratory losses. Arctic tundra ecosystems are highly nitrogen (N) limited, and the indirect effects of warming on nutrient availability will be the most likely outcome of increased temperature on plant productivity. This study aims to understand the effects of nutrient addition on arctic CO2 and H2O exchange in a tundra ecosystem at Toolik Lake Field Station, Alaska. The nutrient addition experiment, which began in 2006, is comprised of 7 fertilization treatments: 0.5, 1, 2, 5, and 10 g m-2 of N as NO3- and NH4+ (1:1) with 0.25, 0.5, 1, 2.5, and 5 g m-2 of phosphorus as PO43-; 5 g m-2 of N as NO3-; 5 g m-2 of N as NH4+, and one control plot. Plot-level CO2 and H2O exchange was measured at 5 light levels 7 times over a four-week period in June and July 2015. We measured ecosystem CO2 and H2O exchange using a rectangular plexiglass chamber (0.49 m2) that was connected to an infrared gas analyzer (LI-840). Other ecosystem variables measured include thaw depth, soil moisture and temperature, and normalized difference vegetation index. After 10 years of nutrient addition, fertilization significantly altered ecosystem C cycling. Soil respiration was greatest in the highest fertilization treatment (2.97 μmol m-2 s-1), increasing linearly with nutrient level at a rate of 0.133 μmol m-2 s-1 per g m-2 of N added (R2=0.914). Net CO2 uptake was greatest under highest fertilization (-2.06 μmol m-2 s-1), decreasing linearly with nutrient addition at a rate of -0.068 μmol m-2 s-1 per g m-2 of N added (R2=0.687). These results suggest that as nutrients become more available under a warmer climate, plant productivity increases may not offset respiratory losses, leading to a positive feedback to global climate.

Multi-trophic resilience of boreal lake ecosystems to forest fires

USGS Publications Warehouse

Lewis, Tyler L.; Lindberg, Mark S.; Schmutz, Joel A.; Bertram, M.R.

2014-01-01

Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.

Multi-trophic resilience of boreal lake ecosystems to forest fires.

PubMed

Lewis, Tyler L; Lindberg, Mark S; Schmutz, Joel A; Bertram, Mark R

2014-05-01

Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll a levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.

Nutrient Sensing Systems in Fish: Impact on Food Intake Regulation and Energy Homeostasis

PubMed Central

Conde-Sieira, Marta; Soengas, José L.

2017-01-01

Evidence obtained in recent years in a few species, especially rainbow trout, supports the presence in fish of nutrient sensing mechanisms. Glucosensing capacity is present in central (hypothalamus and hindbrain) and peripheral [liver, Brockmann bodies (BB, main accumulation of pancreatic endocrine cells in several fish species), and intestine] locations whereas fatty acid sensors seem to be present in hypothalamus, liver and BB. Glucose and fatty acid sensing capacities relate to food intake regulation and metabolism in fish. Hypothalamus is as a signaling integratory center in a way that detection of increased levels of nutrients result in food intake inhibition through changes in the expression of anorexigenic and orexigenic neuropeptides. Moreover, central nutrient sensing modulates functions in the periphery since they elicit changes in hepatic metabolism as well as in hormone secretion to counter-regulate changes in nutrient levels detected in the CNS. At peripheral level, the direct nutrient detection in liver has a crucial role in homeostatic control of glucose and fatty acid whereas in BB and intestine nutrient sensing is probably involved in regulation of hormone secretion from endocrine cells. PMID:28111540

Relationships Between Land Use and Stream Nutrient Concentrations in a Highly Urbanized Tropical Region of Brazil: Thresholds and Riparian Zones.

PubMed

Tromboni, F; Dodds, W K

2017-07-01

Nutrient enrichment in streams due to land use is increasing globally, reducing water quality and causing eutrophication of downstream fresh and coastal waters. In temperate developed countries, the intensive use of fertilizers in agriculture is a main driver of increasing nutrient concentrations, but high levels and fast rates of urbanization can be a predominant issue in some areas of the developing world. We investigated land use in the highly urbanized tropical State of Rio de Janeiro, Brazil. We collected total nitrogen, total phosphorus, and inorganic nutrient data from 35 independent watersheds distributed across the State and characterized land use at a riparian and entire watershed scales upstream from each sample station, using ArcGIS. We used regression models to explain land use influences on nutrient concentrations and to assess riparian protection relationships to water quality. We found that urban land use was the primary driver of nutrient concentration increases, independent of the scale of analyses and that urban land use was more concentrated in the riparian buffer of streams than in the entire watersheds. We also found significant thresholds that indicated strong increases in nutrient concentrations with modest increases in urbanization reaching maximum nutrient concentrations between 10 and 46% urban cover. These thresholds influenced calculation of reference nutrient concentrations, and ignoring them led to higher estimates of these concentrations. Lack of sewage treatment in concert with urban development in riparian zones apparently leads to the observation that modest increases in urban land use can cause large increases in nutrient concentrations.

Effect of cadmium accumulation on mineral nutrient levels in vegetable crops: potential implications for human health.

PubMed

Yang, Danping; Guo, Zhiqiang; Green, Iain D; Xie, Deti

2016-10-01

Consumption of vegetables is often the predominant route whereby humans are exposed to the toxic metal Cd. Health impacts arising from Cd consumption may be influenced by changes in the mineral nutrient content of vegetables, which may occur when plants are exposed to Cd. Here, we subjected model root (carrot) and leaf (lettuce) vegetables to soil Cd concentrations of 0.3, 1.5, 3.3, and 9.6 μg g(-1) for 10 weeks to investigate the effect of Cd exposure on Cd accumulation, growth performance, and mineral nutrient homeostasis. The findings demonstrated that Cd accumulation in lettuce (20.1-71.5 μg g(-1)) was higher than that in carrot (3.2-27.5 μg g(-1)), and accumulation exceeded the maximum permissible Cd concentration in vegetables when soil contained more than 3.3 μg g(-1) of Cd. There was a marked hormetic effect on carrot growth at a soil Cd concentration of 3.3 μg g(-1), but increasing the Cd concentration to 9.6 μg g(-1) caused decreased growth in both crops. Additionally, in most cases, there was a positive correlation between Cd and the mineral nutrient content of vegetables, which was due to physiological changes in the plants causing increased uptake and/or translocation. This may suggest a general mechanism whereby the plant compensated for disrupted mineral nutrient metabolism by increasing nutrient supply to its tissues. Increased nutrient levels could potentially offset some risks posed to humans by increased Cd levels in crops, and we therefore suggest that changes in mineral nutrient levels should be included more widely in the risk assessment of potentially toxic metal contamination. Graphical abstract The Cd concentration (μg g-1 in dry matter) in the root, shoot and translocation factor (TF) of Cd from root to shoot in the carrot and lettuce, and the percentage of root Cd to the gross Cd contents (%) in carrot (C) and lettuce (D) exposed to soil Cd (0 (control), 1, 3, and 9 μg g-1) for 70 days. Values are means ± SD (n = 5).

Natural selection for costly nutrient recycling in simulated microbial metacommunities.

PubMed

Boyle, Richard A; Williams, Hywel T P; Lenton, Timothy M

2012-11-07

Recycling of essential nutrients occurs at scales from microbial communities to global biogeochemical cycles, often in association with ecological interactions in which two or more species utilise each others' metabolic by-products. However, recycling loops may be unstable; sequences of reactions leading to net recycling may be parasitised by side-reactions causing nutrient loss, while some reactions in any closed recycling loop are likely to be costly to participants. Here we examine the stability of nutrient recycling loops in an individual-based ecosystem model based on microbial functional types that differ in their metabolism. A supplied nutrient is utilised by a "source" functional type, generating a secondary nutrient that is subsequently used by two other types-a "mutualist" that regenerates the initial nutrient at a growth rate cost, and a "parasite" that produces a refractory waste product but does not incur any additional cost. The three functional types are distributed across a metacommunity in which separate patches are linked by a stochastic diffusive migration process. Regions of high mutualist abundance feature high levels of nutrient recycling and increased local population density leading to greater export of individuals, allowing the source-mutualist recycling loop to spread across the system. Individual-level selection favouring parasites is balanced by patch-level selection for high productivity, indirectly favouring mutualists due to the synergistic productivity benefits of the recycling loop they support. This suggests that multi-level selection may promote nutrient cycling and thereby help to explain the apparent ubiquity and stability of nutrient recycling in nature.

Limitations to CO2-induced growth enhancement in pot studies.

PubMed

McConnaughay, K D M; Berntson, G M; Bazzaz, F A

1993-07-01

Recently, it has been suggested that small pots may reduce or eliminate plant responses to enriched CO 2 atmospheres due to root restriction. While smaller pot volumes provide less physical space available for root growth, they also provide less nutrients. Reduced nutrient availability alone may reduce growth enhancement under elevated CO 2 . To investigate the relative importance of limited physical rooting space separate from and in conjunction with soil nutrients, we grew plants at ambient and double-ambient CO 2 levels in growth containers of varied volume, shape, nutrient concentration, and total nutrient content. Two species (Abutilon theophrasti, a C 3 dicot with a deep tap root andSetaria faberii, a C 4 monocot with a shallow diffuse root system) were selected for their contrasting physiology and root architecture. Shoot demography was determined weekly and biomass was determined after eight and ten weeks of growth. Increasing total nutrients, either by increasing nutrient concentration or by increasing pot size, increased plant growth. Further, increasing pot size while maintaining equal total nutrients per pot resulted in increased total biomass for both species. CO 2 -induced growth and reproductive yield enhancements were greatest in pots with high nutrient concentrations, regardless of total nutrient content or pot size, and were also mediated by the shape of the pot. CO 2 -induced growth and reproductive yield enhancements were unaffected by pot size (growth) or were greater in small pots (reproductive yield), regardless of total nutrient content, contrary to predictions based on earlier studies. These results suggest that several aspects of growth conditions within pots may influence the CO 2 responses of plants; pot size, pot shape, the concentration and total amount of nutrient additions to pots may lead to over-or underestimates of the CO 2 responses of real-world plants.

A model of phytoplankton blooms.

PubMed

Huppert, Amit; Blasius, Bernd; Stone, Lewi

2002-02-01

A simple model that describes the dynamics of nutrient-driven phytoplankton blooms is presented. Apart from complicated simulation studies, very few models reported in the literature have taken this "bottom-up" approach. Yet, as discussed and justified from a theoretical standpoint, many blooms are strongly controlled by nutrients rather than by higher trophic levels. The analysis identifies an important threshold effect: a bloom will only be triggered when nutrients exceed a certain defined level. This threshold effect should be generic to both natural blooms and most simulation models. Furthermore, predictions are given as to how the peak of the bloom Pmax is determined by initial conditions. A number of counterintuitive results are found. In particular, it is shown that increasing initial nutrient or phytoplankton levels can act to decrease Pmax. Correct predictions require an understanding of such factors as the timing of the bloom and the period of nutrient buildup before the bloom.

Discretionary fortification--a public health perspective.

PubMed

Valerie, Tarasuk

2014-10-17

'Discretionary fortification' refers to the addition of vitamins and minerals to foods at the discretion of manufacturers for marketing purposes, but not as part of a planned public health intervention. While the nutrients added may correspond to needs in the population, an examination of novel beverages sold in Toronto supermarkets revealed added nutrients for which there is little or no evidence of inadequacy in the population. This is consistent with the variable effects of manufacturer-driven fortification on nutrient adequacy observed in the US. Nutrient intakes in excess of Tolerable Upper Intake Levels are now observed in the context of supplement use and high levels of consumption of fortified foods. Expanding discretionary fortification can only increase nutrient exposures, but any health risks associated with chronically high nutrient loads from fortification and supplementation remain to be discovered. Regulatory bodies are focused on the establishment of safe levels of nutrient addition, but their estimation procedures are fraught with untested assumptions and data limitations. The task of determining the benefits of discretionary fortification is being left to consumers, but the nutrition information available to them is insufficient to allow for differentiation of potentially beneficial fortification from gratuitous nutrient additions.

The quality of our Nation's waters-Nutrients in the Nation's streams and groundwater, 1992-2004

USGS Publications Warehouse

Dubrovsky, N.M.; Burow, K.R.; Clark, G.M.; Gronberg, J.M.; Hamilton, P.A.; Hitt, K.J.; Mueller, D.K.; Munn, M.D.; Nolan, B.T.; Puckett, L.J.; Rupert, M.G.; Short, T.M.; Spahr, N.E.; Sprague, L.A.; Wilber, W.G.

2010-01-01

National Findings and Their Implications Although the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatic life, often by large margins. Do NAWQA findings substantiate national concerns for aquatic and human health? National Water-Quality Assessment (NAWQA) findings indicate that nutrient concentrations in streams and groundwater in basins with significant agricultural or urban development are substantially greater than naturally occurring or ?background? levels. For example, median concentrations of total nitrogen and phosphorus in agricultural streams are about 6 times greater than background levels. Findings also indicate that concentrations in streams routinely were 2 to 10 times greater than regional nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic life. Such large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, are needed to meet recommended criteria for streams draining areas with significant agricultural and urban development. Nitrate concentrations above the Federal drinking-water standard-or Maximum Contaminant Level (MCL)-of 10 milligrams per liter (mg/L, as nit-ogen) are relatively uncommon in samples from streams used for drinking water or from relatively deep aquifers; the MCL is exceeded, however, in more than 20 percent of shallow (less than 100 feet below the water table) domestic wells in agricultural areas. This finding raises concerns for human health in rural agricultural areas where shallow groundwater is used for domestic supply and may warn of future contamination of deeper groundwater pumped from public-supply wells. Are levels of nutrients in water increasing or decreasing? A decadal assessment of trends in concentrations of nitrogen and phosphorus from about 1993 to 2003 shows minimal changes in those concentrations in the majority of studied streams across the Nation, and more upward than downward trends in concentrations at sites with changes. These findings underscore the need for reductions in nutrient inputs or management strategies that would reduce transport of nutrients to streams. Upward trends were evident among all land uses, including those only minimally affected by agricultural and (or) urban development, which suggests that additional protection of some of our Nation's most pristine streams warrants consideration. The median of nitrate concentrations in groundwater from 495 wells also increased significantly from 3.2 to 3.4 mg/L (6 percent) during about the same period, and the proportion of wells with concentrations of nitrate greater than the MCL increased from 16 to 21 percent. Nitrate concentrations in water in deep aquifers are likely to increase during the next decade as shallow groundwater with elevated concentrations moves downward. The potential for future contamination of the deep aquifers requires attention because these aquifers commonly are used for public water supply, and because restoration of groundwater is costly and difficult. Long-term and consistent monitoring of nutrients, improved accounting of nutrient sources, and improved tracking and modeling of climatic and landscape changes will be essential for distinguishing trends in nutrient concentrations, understanding the causes of those trends, and accurately tracking the effectiveness of strategies implemented to manage nutrients.

The quality of our Nation's waters-Nutrients in the Nation's streams and groundwater, 1992-2004

USGS Publications Warehouse

Dubrovsky, Neil M.; Burow, Karen R.; Clark, Gregory M.; Gronberg, JoAnn M.; Hamilton, Pixie A.; Hitt, Kerie J.; Mueller, David K.; Munn, Mark D.; Nolan, Bernard T.; Puckett, Larry J.; Rupert, Michael G.; Short, Terry M.; Spahr, Norman E.; Sprague, Lori A.; Wilber, William G.

2010-01-01

National Findings and Their ImplicationsAlthough the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatic life, often by large margins.Do NAWQA findings substantiate national concerns for aquatic and human health?National Water-Quality Assessment (NAWQA) findings indicate that nutrient concentrations in streams and groundwater in basins with significant agricultural or urban development are substantially greater than naturally occurring or “background” levels. For example, median concentrations of total nitrogen and phosphorus in agricultural streams are about 6 times greater than background levels. Findings also indicate that concentrations in streams routinely were 2 to 10 times greater than regional nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic life. Such large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, are needed to meet recommended criteria for streams draining areas with significant agricultural and urban development.Nitrate concentrations above the Federal drinking-water standard—or Maximum Contaminant Level (MCL)—of 10 milligrams per liter (mg/L, as nitrogen) are relatively uncommon in samples from streams used for drinking water or from relatively deep aquifers; the MCL is exceeded, however, in more than 20 percent of shallow (less than 100 feet below the water table) domestic wells in agricultural areas. This finding raises concerns for human health in rural agricultural areas where shallow groundwater is used for domestic supply and may warn of future contamination of deeper groundwater pumped from public‑supply wells.Are levels of nutrients in water increasing or decreasing?A decadal assessment of trends in concentrations of nitrogen and phosphorus from about 1993 to 2003 shows minimal changes in those concentrations in the majority of studied streams across the Nation, and more upward than downward trends in concentrations at sites with changes. These findings underscore the need for reductions in nutrient inputs or management strategies that would reduce transport of nutrients to streams. Upward trends were evident among all land uses, including those only minimally affected by agricultural and (or) urban development, which suggests that additional protection of some of our Nation’s most pristine streams warrants consideration.The median of nitrate concentrations in groundwater from 495 wells also increased significantly from 3.2 to 3.4 mg/L (6 percent) during about the same period, and the proportion of wells with concentrations of nitrate greater than the MCL increased from 16 to 21 percent. Nitrate concentrations in water in deep aquifers are likely to increase during the next decade as shallow groundwater with elevated concentrations moves downward. The potential for future contamination of the deep aquifers requires attention because these aquifers commonly are used for public water supply, and because restoration of groundwater is costly and difficult.Long-term and consistent monitoring of nutrients, improved accounting of nutrient sources, and improved tracking and modeling of climatic and landscape changes will be essential for distinguishing trends in nutrient concentrations, understanding the causes of those trends, and accurately tracking the effectiveness of strategies implemented to manage nutrients.

Erythroneura lawsoni abundance and feeding injury levels are influenced by foliar nutrient status in intensively managed American sycamore.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coyle, David, Robert: Aubrey, Doug, Patric; Bentz, Jo-Ann

2010-01-01

Abstract 1 Abundance and feeding injury of the leafhopper Erythroneura lawsoni Robinson was measured in an intensively-managed American sycamore Platanus occidentalis L. plantation. Trees were planted in spring 2000 in a randomized complete block design, and received one of three annual treatments: (i) fertilization (120 kg N/ha/year); (ii) irrigation (3.0 cm/week); (iii) fertilization + irrigation; or (iv) control (no treatment). 2 Foliar nutrient concentrations were significantly influenced by the treatments because only sulphur and manganese levels were not statistically greater in trees receiving fertilization. 3 Over 116 000 E. lawsoni were captured on sticky traps during the study. Leafhopper abundancemore » was highest on nonfertilized trees for the majority of the season, and was positively correlated with foliar nutrient concentrations. Significant temporal variation in E. lawsoni abundance occurred, suggesting five discrete generations in South Carolina. 4 Significant temporal variation occurred in E. lawsoni foliar injury levels, with the highest injury ratings occurring in late June and August. Foliar injury was negatively correlated with foliar nutrient content, and higher levels of injury occurred more frequently on nonfertilized trees. 5 The results obtained in the present study indicated that increased E. lawsoni abundance occurred on trees that did not receive fertilization. Nonfertilized trees experienced greater foliar injury, suggesting that lower foliar nutrient status may have led to increased levels of compensatory feeding.« less

The competing impacts of climate change and nutrient reductions on dissolved oxygen in Chesapeake Bay

NASA Astrophysics Data System (ADS)

Irby, Isaac D.; Friedrichs, Marjorie A. M.; Da, Fei; Hinson, Kyle E.

2018-05-01

The Chesapeake Bay region is projected to experience changes in temperature, sea level, and precipitation as a result of climate change. This research uses an estuarine-watershed hydrodynamic-biogeochemical modeling system along with projected mid-21st-century changes in temperature, freshwater flow, and sea level rise to explore the impact climate change may have on future Chesapeake Bay dissolved-oxygen (DO) concentrations and the potential success of nutrient reductions in attaining mandated estuarine water quality improvements. Results indicate that warming bay waters will decrease oxygen solubility year-round, while also increasing oxygen utilization via respiration and remineralization, primarily impacting bottom oxygen in the spring. Rising sea level will increase estuarine circulation, reducing residence time in bottom waters and increasing stratification. As a result, oxygen concentrations in bottom waters are projected to increase, while oxygen concentrations at mid-depths (3 < DO < 5 mg L-1) will typically decrease. Changes in precipitation are projected to deliver higher winter and spring freshwater flow and nutrient loads, fueling increased primary production. Together, these multiple climate impacts will lower DO throughout the Chesapeake Bay and negatively impact progress towards meeting water quality standards associated with the Chesapeake Bay Total Maximum Daily Load. However, this research also shows that the potential impacts of climate change will be significantly smaller than improvements in DO expected in response to the required nutrient reductions, especially at the anoxic and hypoxic levels. Overall, increased temperature exhibits the strongest control on the change in future DO concentrations, primarily due to decreased solubility, while sea level rise is expected to exert a small positive impact and increased winter river flow is anticipated to exert a small negative impact.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borer, Elizabeth T.; et al, et al

Human alterations to nutrient cycles1,2 and herbivore communities3–7 are affecting global biodiversity dramatically2. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems8,9. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces tomore » control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.« less

Nutrient discharge from China’s aquaculture industry and associated environmental impacts

NASA Astrophysics Data System (ADS)

Zhang, Ying; Bleeker, Albert; Liu, Junguo

2015-04-01

China’s aquaculture industry accounts for the largest share of the world’s fishery production, and provides a principal source of protein for the nation’s booming population. However, the environmental effects of the nutrient loadings produced by this industry have not been systematically studied or reviewed. Few quantitative estimates exist for nutrient discharge from aquaculture and the resultant nutrient enrichment in waters and sediments. In this paper, we evaluate nutrient discharge from aquacultural systems into aquatic ecosystems and the resulting nutrient enrichment of water and sediments, based on data from 330 cases in 51 peer-reviewed publications. Nitrogen use efficiency ranged from 11.7% to 27.7%, whereas phosphorus use efficiency ranged from 8.7% to 21.2%. In 2010, aquacultural nutrient discharges into Chinese aquatic ecosystems included 1044 Gg total nitrogen (184 Gg N from mariculture; 860 Gg N freshwater culture) and 173 Gg total phosphorus (22 Gg P from mariculture; 151 Gg P from freshwater culture). Water bodies and sediments showed high levels of nutrient enrichment, especially in closed pond systems. However, this does not mean that open aquacultural systems have smaller nutrient losses. Improvement of feed efficiency in cage systems and retention of nutrients in closed systems will therefore be necessary. Strategies to increase nutrient recycling, such as integrated multi-trophic aquaculture, and social measures, such as subsidies, should be increased in the future. We recommend the recycling of nutrients in water and sediments by hybrid agricultural-aquacultural systems and the adoption of nutrient use efficiency as an indicator at farm or regional level for the sustainable development of aquaculture; such indicators; together with water quality indicators, can be used to guide evaluations of technological, policy, and economic approaches to improve the sustainability of Chinese aquaculture.

Phytotoxic effects of nickel on yield and concentration of macro- and micro-nutrients in sunflower (Helianthus annuus L.) achenes.

PubMed

Ahmad, Muhammad Sajid Aqeel; Ashraf, Muhammad; Hussain, Mumtaz

2011-01-30

The phytotoxic effects of varying levels of nickel (0, 10, 20, 30, and 40 mg L(-1)) on growth, yield and accumulation of macro- and micro-nutrients in leaves and achenes of sunflower (Helianthus annuus L.) were appraised in this study. A marked reduction in root and shoot fresh biomass was recorded at higher Ni levels. Nickel stress also caused a substantial decrease in all macro- and micro-nutrients in leaves and achenes. The lower level of Ni (10 mg L(-1)) had a non-significant effect on various yield attributes, but higher Ni levels considerably decreased these parameters. Higher Ni levels decreased the concentrations of Ca, Mn and Fe in achenes. In contrast, achene N, K, Zn, Mn and Cu decreased consistently with increasing level of Ni, even at lower level (10 mg L(-1)). Sunflower hybrid Hysun-33 had better yield and higher most of the nutrients in achenes as compared with SF-187. The maximum reduction in all parameters was observed at the maximum level of nickel (40 mg L(-1)) where almost all parameters were reduced more than 50% of those of control plants. In conclusion, the pattern of uptake and accumulation of different nutrients in sunflower plants were nutrient- and cultivar-specific under Ni-stress. Copyright © 2010 Elsevier B.V. All rights reserved.

Potential changes in bacterial metabolism associated with increased water temperature and nutrient inputs in tropical humic lagoons.

PubMed

Scofield, Vinicius; Jacques, Saulo M S; Guimarães, Jean R D; Farjalla, Vinicius F

2015-01-01

Temperature and nutrient concentrations regulate aquatic bacterial metabolism. However, few studies have focused on the effect of the interaction between these factors on bacterial processes, and none have been performed in tropical aquatic ecosystems. We analyzed the main and interactive effects of changes in water temperature and N and P concentrations on bacterioplankton production (BP), bacterioplankton respiration (BR) and bacterial growth efficiency (BGE) in tropical coastal lagoons. We used a factorial design with three levels of water temperature (25, 30, and 35°C) and four levels of N and/or P additions (Control, N, P, and NP additions) in five tropical humic lagoons. When data for all lagoons were pooled together, a weak interaction was observed between the increase in water temperature and the addition of nutrients. Water temperature alone had the greatest impact on bacterial metabolism by increasing BR, decreasing BP, and decreasing BGE. An increase of 1°C lead to an increase of ~4% in BR, a decrease of ~0.9% in BP, and a decrease of ~4% in BGE. When data were analyzed separately, lagoons responded differently to nutrient additions depending on Dissolved Organic Carbon (DOC) concentration. Lagoons with lowest DOC concentrations showed the strongest responses to nutrient additions: BP increased in response to N, P, and their interaction, BR increased in response to N and the interaction between N and P, and BGE was negatively affected, mainly by the interaction between N and P additions. Lagoons with the highest DOC concentrations showed almost no significant relationship with nutrient additions. Taken together, these results show that different environmental drivers impact bacterial processes at different scales. Changes of bacterial metabolism related to the increase of water temperature are consistent between lagoons, therefore their consequences can be predicted at a regional scale, while the effect of nutrient inputs is specific to different lagoons but seems to be related to the DOC concentration.

Potential changes in bacterial metabolism associated with increased water temperature and nutrient inputs in tropical humic lagoons

PubMed Central

Scofield, Vinicius; Jacques, Saulo M. S.; Guimarães, Jean R. D.; Farjalla, Vinicius F.

2015-01-01

Temperature and nutrient concentrations regulate aquatic bacterial metabolism. However, few studies have focused on the effect of the interaction between these factors on bacterial processes, and none have been performed in tropical aquatic ecosystems. We analyzed the main and interactive effects of changes in water temperature and N and P concentrations on bacterioplankton production (BP), bacterioplankton respiration (BR) and bacterial growth efficiency (BGE) in tropical coastal lagoons. We used a factorial design with three levels of water temperature (25, 30, and 35°C) and four levels of N and/or P additions (Control, N, P, and NP additions) in five tropical humic lagoons. When data for all lagoons were pooled together, a weak interaction was observed between the increase in water temperature and the addition of nutrients. Water temperature alone had the greatest impact on bacterial metabolism by increasing BR, decreasing BP, and decreasing BGE. An increase of 1°C lead to an increase of ~4% in BR, a decrease of ~0.9% in BP, and a decrease of ~4% in BGE. When data were analyzed separately, lagoons responded differently to nutrient additions depending on Dissolved Organic Carbon (DOC) concentration. Lagoons with lowest DOC concentrations showed the strongest responses to nutrient additions: BP increased in response to N, P, and their interaction, BR increased in response to N and the interaction between N and P, and BGE was negatively affected, mainly by the interaction between N and P additions. Lagoons with the highest DOC concentrations showed almost no significant relationship with nutrient additions. Taken together, these results show that different environmental drivers impact bacterial processes at different scales. Changes of bacterial metabolism related to the increase of water temperature are consistent between lagoons, therefore their consequences can be predicted at a regional scale, while the effect of nutrient inputs is specific to different lagoons but seems to be related to the DOC concentration. PMID:25926827

Excess nutrients in hydroponic solutions alter nutrient content of rice, wheat, and potato.

PubMed

McKeehen, J D; Mitchell, C A; Wheeler, R M; Bugbee, B; Nielsen, S S

1996-01-01

Environment has significant effects on the nutrient content of field-grown crop plants. Little is known, however, about compositional changes caused by controlled environments in which plants receive only artificial radiation and soilless, hydroponic culture. This knowledge is essential for developing a safe, nutritious diet in a Controlled Ecological Life-Support System (CELSS). Three crops that are candidates for inclusion in a CELSS (rice, wheat, and white potato) were grown both in the field and in controlled environments where the hydroponic nutrient solution, photosynthetic photon flux (PPF), and CO2 level were manipulated to achieve rapid growth rates. Plants were harvested at maturity, separated into discrete parts, and dried prior to analysis. Plant materials were analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate, minerals, and amino-acid composition. The effect of environment on nutrient content varied by crop and plant part. Total N and nonprotein N (NPN) contents of plant biomass generally increased under controlled-environment conditions compared to field conditions, especially for leafy plant parts and roots. Nitrate levels were increased in hydroponically-grown vegetative tissues, but nitrate was excluded from grains and tubers. Mineral content changes in plant tissue included increased phosphorus and decreased levels of certain micronutrient elements under controlled-environment conditions. These findings suggest that cultivar selection, genetic manipulation, and environmental control could be important to obtain highly nutritious biomass in a CELSS.

Excess nutrients in hydroponic solutions alter nutrient content of rice, wheat, and potato

NASA Technical Reports Server (NTRS)

McKeehen, J. D.; Mitchell, C. A.; Wheeler, R. M.; Bugbee, B.; Nielsen, S. S.

1996-01-01

Environment has significant effects on the nutrient content of field-grown crop plants. Little is known, however, about compositional changes caused by controlled environments in which plants receive only artificial radiation and soilless, hydroponic culture. This knowledge is essential for developing a safe, nutritious diet in a Controlled Ecological Life-Support System (CELSS). Three crops that are candidates for inclusion in a CELSS (rice, wheat, and white potato) were grown both in the field and in controlled environments where the hydroponic nutrient solution, photosynthetic photon flux (PPF), and CO2 level were manipulated to achieve rapid growth rates. Plants were harvested at maturity, separated into discrete parts, and dried prior to analysis. Plant materials were analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate, minerals, and amino-acid composition. The effect of environment on nutrient content varied by crop and plant part. Total N and nonprotein N (NPN) contents of plant biomass generally increased under controlled-environment conditions compared to field conditions, especially for leafy plant parts and roots. Nitrate levels were increased in hydroponically-grown vegetative tissues, but nitrate was excluded from grains and tubers. Mineral content changes in plant tissue included increased phosphorus and decreased levels of certain micronutrient elements under controlled-environment conditions. These findings suggest that cultivar selection, genetic manipulation, and environmental control could be important to obtain highly nutritious biomass in a CELSS.

Excess nutrients in hydroponic solutions alter nutrient content of rice, wheat, and potato

NASA Astrophysics Data System (ADS)

McKeehen, J. D.; Mitchell, C. A.; Wheeler, R. M.; Bugbee, B.; Nielsen, S. S.

Environment has significant effects on the nutrient content of field-grown crop plants. Little is known, however, about compositional changes caused by controlled environments in which plants receive only artificial radiation and soilless, hydroponic culture. This knowledge is essential for developing a safe, nutritious diet in a Controlled Ecological Life-Support System (CELSS). Three crops that are candidates for inclusion in a CELSS (rice, wheat, and white potato) were grown both in the field and in controlled environments where the hydroponic nutrient solution, photosynthetic photon flux (PPF), and CO_2 level were manipulated to achieve rapid growth rates. Plants were harvested at maturity, separated into discrete parts, and dried prior to analysis. Plant materials were analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate, minerals, and amino-acid composition. The effect of environment on nutrient content varied by crop and plant part. Total N and nonprotein N (NPN) contents of plant biomass generally increased under controlled-environment conditions compared to field conditions, especially for leafy plant parts and roots. Nitrate levels were increased in hydroponically-grown vegetative tissues, but nitrate was excluded from grains and tubers. Mineral content changes in plant tissue included increased phosphorus and decreased levels of certain micronutrient elements under controlled-environment conditions. These findings suggest that cultivar selection, genetic manipulation, and environmental control could be important to obtain highly nutritious biomass in a CELSS.

Silicon availability modifies nutrient use efficiency and content, C:N:P stoichiometry, and productivity of winter wheat (Triticum aestivum L.)

NASA Astrophysics Data System (ADS)

Neu, Silke; Schaller, Jörg; Dudel, E. Gert

2017-01-01

Silicon (Si) is known as beneficial element for graminaceous plants. The importance of Si for plant functioning of cereals was recently emphasized. However, about the effect of Si availability on biomass production, grain yield, nutrient status and nutrient use efficiency for wheat (Triticum aestivum L.), as one of the most important crop plants worldwide, less is known so far. Consequently, we assessed the effect of a broad range of supply levels of amorphous SiO2 on wheat plant performance. Our results revealed that Si is readily taken up and accumulated basically in aboveground vegetative organs. Carbon (C) and phosphorus (P) status of plants were altered in response to varying Si supply. In bulk straw biomass C concentration decreased with increasing Si supply, while P concentration increased from slight limitation towards optimal nutrition. Thereby, aboveground biomass production increased at low to medium supply levels of silica whereas grain yield increased at medium supply level only. Nutrient use efficiency was improved by Si insofar that biomass production was enhanced at constant nitrogen (N) status of substrate and plants. Consequently, our findings imply fundamental influences of Si on C turnover, P availability and nitrogen use efficiency for wheat as a major staple crop.

Variation in wood nutrients along a tropical soil fertility gradient.

PubMed

Heineman, Katherine D; Turner, Benjamin L; Dalling, James W

2016-07-01

Wood contains the majority of the nutrients in tropical trees, yet controls over wood nutrient concentrations and their function are poorly understood. We measured wood nutrient concentrations in 106 tree species in 10 forest plots spanning a regional fertility gradient in Panama. For a subset of species, we quantified foliar nutrients and wood density to test whether wood nutrients scale with foliar nutrients at the species level, or wood nutrient storage increases with wood density as predicted by the wood economics spectrum. Wood nutrient concentrations varied enormously among species from fourfold in nitrogen (N) to > 30-fold in calcium (Ca), potassium (K), magnesium (Mg) and phosphorus (P). Community-weighted mean wood nutrient concentrations correlated positively with soil Ca, K, Mg and P concentrations. Wood nutrients scaled positively with leaf nutrients, supporting the hypothesis that nutrient allocation is conserved across plant organs. Wood P was most sensitive to variation in soil nutrient availability, and significant radial declines in wood P indicated that tropical trees retranslocate P as sapwood transitions to heartwood. Wood P decreased with increasing wood density, suggesting that low wood P and dense wood are traits associated with tree species persistence on low fertility soils. Substantial variation among species and communities in wood nutrient concentrations suggests that allocation of nutrients to wood, especially P, influences species distributions and nutrient dynamics in tropical forests. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Assessing the impacts of salinity and nutrient stress to Ruppia ...

EPA Pesticide Factsheets

Healthy seagrass beds were once found throughout the shallow areas of Narragansett Bay, R.I. but have disappeared due to infilling, pollution and disease. In Greenwich Bay, a highly developed embayment within Narragansett Bay, Ruppia maritima has colonized an area on the northern shore historically dominated by Zostera marina. Ruppia is extremely salinity tolerant, and may also be more nutrient tolerant than Zostera. To test this hypothesis 6-week microcosm experiments were conducted in the summers of 2014 and 2015. Microcosms were renewed daily to simulate tidal flushing and the water column was dosed with a 15N tracer for the first week of the experiments. In the 2014 microcosm experiment two salinity (20, 30 ppt) and four nutrient (0, 5, 10, 30 µM inorganic N) levels were used to test the species’ relative tolerance. This experiment yielded structurally significant results for Ruppia but no significant differences were detected for Zostera. In 2015 this experiment was performed for a second time with lower salinity (5, 30 ppt) and higher nutrients (0, 30, 100, 300, 1000 µM inorganic N) in order to determine Zostera’s tolerance to nutrient and salinity stress and confirm the previously observed Ruppia results. Both species had significant structural responses to the nutrient and salinity variables. Isotopic analysis run on above-ground tissue indicated that with increasing nutrient levels δ15N in the seagrass shoots increased, suggesting that nutrients

Do elevated nutrients and organic carbon on Philippine reefs increase the prevalence of coral disease?

NASA Astrophysics Data System (ADS)

Kaczmarsky, L.; Richardson, L. L.

2011-03-01

Characterizations of Philippine coral diseases are very limited. The two most common, ulcerative white spot disease (UWS) and massive Porites growth anomalies (MPGA), target the genus Porites, a dominant reef-building genus. This is the first investigation in the Philippines to detect positive correlations between coral disease, nutrient levels, and organic carbon. A total of 5,843 Porites colonies were examined. Water and sediment samples were collected for analyses of nutrients (total nitrogen and phosphorus) and total organic carbon at 15 sites along a 40.5 km disease gradient, which was previously shown to positively correlate with human population levels. Results suggest that outbreaks of UWS and MPGAs are driven by elevated nutrient and organic carbon levels. Although the variables analyzed could be proxies for other causative agents (e.g., high sediment levels), the results provide quantitative evidence linking relatively higher coral disease prevalence to an anthropogenically impacted environment.

Independence of nutrient limitation and carbon dioxide impacts on the Southern Ocean coccolithophore Emiliania huxleyi.

PubMed

Müller, Marius N; Trull, Thomas W; Hallegraeff, Gustaaf M

2017-08-01

Future oceanic conditions induced by anthropogenic greenhouse gas emissions include warming, acidification and reduced nutrient supply due to increased stratification. Some parts of the Southern Ocean are expected to show rapid changes, especially for carbonate mineral saturation. Here we compare the physiological response of the model coccolithophore Emiliania huxleyi (strain EHSO 5.14, originating from 50 o S, 149 o E) with pH/CO 2 gradients (mimicking ocean acidification ranging from 1 to 4 × current pCO 2 levels) under nutrient-limited (nitrogen and phosphorus) and -replete conditions. Both nutrient limitations decreased per cell photosynthesis (particulate organic carbon (POC) production) and calcification (particulate inorganic carbon (PIC) production) rates for all pCO 2 levels, with more than 50% reductions under nitrogen limitation. These impacts, however, became indistinguishable from nutrient-replete conditions when normalized to cell volume. Calcification decreased three-fold and linearly with increasing pCO 2 under all nutrient conditions, and was accompanied by a smaller ~30% nonlinear reduction in POC production, manifested mainly above 3 × current pCO 2 . Our results suggest that normalization to cell volume allows the major impacts of nutrient limitation (changed cell sizes and reduced PIC and POC production rates) to be treated independently of the major impacts of increasing pCO 2 and, additionally, stresses the importance of including cell volume measurements to the toolbox of standard physiological analysis of coccolithophores in field and laboratory studies.

Independence of nutrient limitation and carbon dioxide impacts on the Southern Ocean coccolithophore Emiliania huxleyi

PubMed Central

Müller, Marius N; Trull, Thomas W; Hallegraeff, Gustaaf M

2017-01-01

Future oceanic conditions induced by anthropogenic greenhouse gas emissions include warming, acidification and reduced nutrient supply due to increased stratification. Some parts of the Southern Ocean are expected to show rapid changes, especially for carbonate mineral saturation. Here we compare the physiological response of the model coccolithophore Emiliania huxleyi (strain EHSO 5.14, originating from 50oS, 149oE) with pH/CO2 gradients (mimicking ocean acidification ranging from 1 to 4 × current pCO2 levels) under nutrient-limited (nitrogen and phosphorus) and -replete conditions. Both nutrient limitations decreased per cell photosynthesis (particulate organic carbon (POC) production) and calcification (particulate inorganic carbon (PIC) production) rates for all pCO2 levels, with more than 50% reductions under nitrogen limitation. These impacts, however, became indistinguishable from nutrient-replete conditions when normalized to cell volume. Calcification decreased three-fold and linearly with increasing pCO2 under all nutrient conditions, and was accompanied by a smaller ~30% nonlinear reduction in POC production, manifested mainly above 3 × current pCO2. Our results suggest that normalization to cell volume allows the major impacts of nutrient limitation (changed cell sizes and reduced PIC and POC production rates) to be treated independently of the major impacts of increasing pCO2 and, additionally, stresses the importance of including cell volume measurements to the toolbox of standard physiological analysis of coccolithophores in field and laboratory studies. PMID:28430186

Bacteria foraging in turbulent waters

NASA Astrophysics Data System (ADS)

Taylor, John; Tang, Wenbo; Stocker, Roman

2009-11-01

Marine bacteria are the Ocean's recyclers, contributing to as much as 50% of the productivity of the marine food web. Bacteria forage on patches of dissolved nutrients using chemotaxis, the ability to swim up chemical gradients. As turbulence is ubiquitous in the Ocean, it is important to understand how turbulent flow conditions affect bacterial foraging. We used three-dimensional, isotropic direct numerical simulations coupled with a bacterial transport equation to address this problem. After the flow is continuously forced until it reaches a steady state, microscale nutrient patches are injected into the turbulent flow, and stirring produces thin nutrient filaments. Two populations of bacteria compete against each other: one population is motile and chemotactic (`active'), the other is non-motile (`passive'). The distribution of both populations is initially uniform. Chemotaxis allows active bacteria to cluster near the center of the nutrient filaments, increasing their nutrient uptake relative to passive bacteria. Increasing the turbulence intensity increases the short-term chemotactic advantage by quickly producing large gradients in the nutrient concentration, but also leads to rapid mixing of the nutrient field, which makes the chemotactic advantage short-lived. The results suggest that the evolutionary advantage of chemotaxis, based on the increase in nutrient uptake relative to the energetic cost of swimming, strongly depends on the turbulence level.

Eutrophication triggers contrasting multilevel feedbacks on litter accumulation and decomposition in fens.

PubMed

Emsens, W-J; Aggenbach, C J S; Grootjans, A P; Nfor, E E; Schoelynck, J; Struyf, E; van Diggelen, R

2016-10-01

Eutrophication is a major threat for the persistence of nutrient-poor fens, as multilevel feedbacks on decomposition rates could trigger carbon loss and increase nutrient cycling. Here, we experimentally investigate the effects of macronutrient (NPK) enrichment on litter quality of six species of sedge (Carex sp.), which we relate to litter decomposition rates in a nutrient-poor and nutrient-rich environment. Our research focused on four levels: we examined how eutrophication alters (1) fresh litter production ("productivity shift"), (2) litter stoichiometry within the same species ("intraspecific shift"), (3) overall litter stoichiometry of the vegetation under the prediction that low-competitive species are outcompeted by fast-growing competitors ("interspecific shift"), and (4) litter decomposition rates due to an altered external environment (e.g., shifts in microbial activity; "exogenous shift"). Eutrophication triggered a strong increase in fresh litter production. Moreover, individuals of the same species produced litter with lower C:N and C:P ratios, higher K contents, and lower lignin, Ca and Mg contents (intraspecific shift), which increased litter decomposability. In addition, species typical for eutrophic conditions produced more easily degradable litter than did species typical for nutrient-poor conditions (interspecific shift). However, the effects of nutrient loading of the external environment (exogenous shift) were contradictory. Here, interactions between litter type and ambient nutrient level indicate that the (exogenous) effects of eutrophication on litter decomposition rates are strongly dependent of litter quality. Moreover, parameters of litter quality only correlated with decomposition rates for litter incubated in nutrient-poor environments, but not in eutrophic environments. This suggests that rates of litter decomposition can be uncoupled from litter stoichiometry under eutrophic conditions. In conclusion, our results show that eutrophication affects litter accumulation and -decomposition at multiple levels, in which stimulatory and inhibitory effects interact. The cumulative effect of these interactions ultimately determine whether peatlands remain sinks or become sources of carbon under eutrophic conditions. © 2016 by the Ecological Society of America.

Cumulative Effects of Nutrient Enrichment and Elevated Temperature Compromise the Early Life History Stages of the Coral Acropora tenuis

PubMed Central

Noonan, Sam H. C.; Willis, Bette L.; Fabricius, Katharina E.; Negri, Andrew P.

2016-01-01

Inshore coral reefs are experiencing the combined pressures of excess nutrient availability associated with coastal activities and warming seawater temperatures. Both pressures are known to have detrimental effects on the early life history stages of hard corals, but studies of their combined effects on early demographic stages are lacking. We conducted a series of experiments to test the combined effects of nutrient enrichment (three levels) and elevated seawater temperature (up to five levels) on early life history stages of the inshore coral Acropora tenuis, a common species in the Indo-Pacific and Red Sea. Gamete fertilization, larval survivorship and larval settlement were all significantly reduced as temperature increased, but only fertilization was further affected by simultaneous nutrient enrichment. Combined high temperatures and nutrient enrichment affected fertilization in an additive manner, whereas embryo abnormalities increased synergistically. Higher than normal temperatures (32°C) increased coral juvenile growth rates 1.6-fold, but mortality also increased by 50%. The co-occurrence of nutrient enrichment with high temperatures reduced juvenile mortality to 36%, ameliorating temperature stress (antagonistic interaction). Overall, the types of effect (additive vs synergistic or antagonistic) and their magnitude varied among life stages. Gamete and embryo stages were more affected by temperature stress and, in some cases, also by nutrient enrichment than juveniles. The data suggest that coastal runoff events might exacerbate the impacts of warming temperatures on fertilization if these events co-occur during corals spawning. The cumulative impacts of simultaneous exposure to nutrient enrichment and elevated temperatures over all early life history stages increases the likelihood for failure of larval supply and recruitment for this coral species. Our results suggest that improving the water quality of river discharges into coastal areas might help to enhance the thermal tolerances of early life history stages in this common coral species. PMID:27575699

Effect of drought on nutrient uptake and the levels of nutrient-uptake proteins in roots of drought-sensitive and –tolerant grasses

USDA-ARS?s Scientific Manuscript database

Climate models predict a reduction in precipitation and an increase in evapotranspiration rates in many regions of the world in coming decades, resulting in increased drought. In addition to decreasing plant growth and reproduction, drought also decreases the concentration (%) of nitrogen (N) and p...

CO2 and nutrient-driven changes across multiple levels of organization in Zostera noltii ecosystems

NASA Astrophysics Data System (ADS)

Martínez-Crego, B.; Olivé, I.; Santos, R.

2014-12-01

Increasing evidence emphasizes that the effects of human impacts on ecosystems must be investigated using designs that incorporate the responses across levels of biological organization as well as the effects of multiple stressors. Here we implemented a mesocosm experiment to investigate how the individual and interactive effects of CO2 enrichment and eutrophication scale-up from changes in primary producers at the individual (biochemistry) or population level (production, reproduction, and/or abundance) to higher levels of community (macroalgae abundance, herbivory, and global metabolism), and ecosystem organization (detritus release and carbon sink capacity). The responses of Zostera noltii seagrass meadows growing in low- and high-nutrient field conditions were compared. In both meadows, the expected CO2 benefits on Z. noltii leaf production were suppressed by epiphyte overgrowth, with no direct CO2 effect on plant biochemistry or population-level traits. Multi-level meadow response to nutrients was faster and stronger than to CO2. Nutrient enrichment promoted the nutritional quality of Z. noltii (high N, low C : N and phenolics), the growth of epiphytic pennate diatoms and purple bacteria, and shoot mortality. In the low-nutrient meadow, individual effects of CO2 and nutrients separately resulted in reduced carbon storage in the sediment, probably due to enhanced microbial degradation of more labile organic matter. These changes, however, had no effect on herbivory or on community metabolism. Interestingly, individual effects of CO2 or nutrient addition on epiphytes, shoot mortality, and carbon storage were attenuated when nutrients and CO2 acted simultaneously. This suggests CO2-induced benefits on eutrophic meadows. In the high-nutrient meadow, a striking shoot decline caused by amphipod overgrazing masked the response to CO2 and nutrient additions. Our results reveal that under future scenarios of CO2, the responses of seagrass ecosystems will be complex and context-dependent, being mediated by epiphyte overgrowth rather than by direct effects on plant biochemistry. Overall, we found that the responses of seagrass meadows to individual and interactive effects of CO2 and nutrient enrichment varied depending on interactions among species and connections between organization levels.

Gastropod growth and survival as bioindicators of stress associated with high nutrients in the intertidal of a shallow temperate estuary

NASA Astrophysics Data System (ADS)

Marsden, Islay D.; Baharuddin, Nursalwa

2015-04-01

The effects of multiple stressors on estuarine organisms are not well understood. Using cage experiments we measured the survival and growth of the pulmonate gastropod Amphibola crenata at five locations which differed contaminant levels. Water nutrients came from a nearby sewage treatment works and the sediment contained low levels of trace metals. Over 6 weeks of exposure, sediment surface chlorophyll levels varied amongst locations. The Chl a values were positively correlated with sediment N and P and trace metals As, Cd, Cu, Pb and Zn. Pulmonate survival depended on location, highest mortality was from a site close to the treatment plant and mortality rate of large individuals decreased significantly with distance away from it. For four locations, medium A. crenata had higher survival than small (juveniles) or adults. Growth rates of small individuals exceeded those for medium and large A. crenata. The mean length increment/week for medium gastropods ranged between 0.49 and 1.11 mm and was negatively correlated with the amount of Chl a in the surface sediment, suggesting the negative effects of eutrophication on gastropod growth. Growth rate of the pulmonate was not correlated with nutrient concentration or trace metal concentrations in the sediment. The dry weight condition index (CI) did not correlate with the growth rate, and for medium individuals, was unaffected by any of the environmental variables. The CI of small individuals was negatively affected by increasing water nutrient levels and the CI of large individuals negatively affected by increasing sediment nutrients and trace metal concentrations. The results from this study suggest that gastropod growth and survival could be used as tools to monitor the effects of changing nutrient levels and recovery from eutrophication within temperate estuaries.

RESPONSE OF NUTRIENTS, BIOFILM, AND BENTHIC INSECTS TO SALMON CARCASS ADDITION

EPA Science Inventory

Salmon carcass addition to streams is expected to increase stream productivity at multiple trophic levels. This study examined stream nutrient (nitrogen, phosphorus, and carbon), epilithic biofilm (ash-free dry mass and chlorophyll a), leaf-litter decomposition, and macroinverte...

Nutrients removal and substrate enzyme activities in vertical subsurface flow constructed wetlands for mariculture wastewater treatment: Effects of ammonia nitrogen loading rates and salinity levels.

PubMed

Li, Meng; Liang, Zhenlin; Callier, Myriam D; Roque d'orbcastel, Emmanuelle; Sun, Guoxiang; Ma, Xiaona; Li, Xian; Wang, Shunkui; Liu, Ying; Song, Xiefa

2018-06-01

This study aims to investigate the effects of ammonia nitrogen loading rates and salinity levels on nutrients removal rates and substrate enzyme activities of constructed wetland (CW) microcosms planted with Salicornia bigelovii treating mariculture wastewater. Activities of urease (UA), dehydrogenase (DA), protease (PrA) and phosphatase (PA) were considered. Using principal component analysis (PCA), nutrient removal index (NRI) and enzyme activity index (EAI) were developed to evaluate the effects. The results revealed that increasing ammonia nitrogen loading rates had positive effects on nitrogen removal rates (i.e. NH 4 -N and DIN) and enhanced substrate enzyme activities. Compared with low salinity (i.e. 15 and 22), high salinity levels (i.e. 29 and 36) enhanced nutrients removal rates, DA and UA, but weaken PA and PrA. In conclusion, CW microcosms with Salicornia bigelovii can be used for the removal of nutrients under a range of ammonia nitrogen loadings and high salinity levels. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Fertile Grounds Initiative: A new way to close nutrient flows at regional level resulting in better agricultural productivity and less environmental losses

NASA Astrophysics Data System (ADS)

van Beek, Christy; van Duivenbooden, Niek; Noij, Gert-Jan

2014-05-01

The threat of declining soil fertility levels is well known. Yet, and despite numerous efforts, we seem incapable of changing the current situation of sink areas in developed countries and depletion areas in developing countries. With negative consequences (i.e. loss in productive capacity and loss in environmental quality) in both areas. Moreover, due to globalization and urbanization nutrient flows become increasingly disconnected. Soil nutrient depletion cannot simply be compensated for with mineral fertilisers, for the following reasons: • mineral fertilisers are often not affordable for smallholders and fertiliser subsidy systems are not always successful • mineral fertilisers do not contain organic matter and therefore do not halt the degradation of the soil • mineral fertilisers work best in combination with organic sources of nutrients (compost, farm yard manure, etc.) • To halt soil degradation an integrated approach is needed, including reducing losses of nutrients and organic matter from soils at risk. Presently, more actors are getting involved in reallocation of nutrients, especially in the energy and waste sector. Time has come for a new approach to bring together demands and supplies for nutrients. We therefore present the Fertile Grounds Initiative: a broker for nutrient supply and demand in the region. The Fertile Grounds Initiative is based on the findings that: • Organic ánd mineral nutrients are required for increased and sustainable production; • Nutrients have a value and should be treated as such; • Due to globalization and urbanization nutrient flows are ever more polarized between depletion and concentration areas; • The demand for energy poses new threats and opportunities for nutrient management. In the Fertile Grounds Initiative nutrient suppliers from the energy sector, waste management, fertilizer companies, etc. and demands for nutrients from farmers are brought together in a dynamic platform. This platform acts as a nutrient bank and integrates different sources of nutrients into high quality crop nutrition products. A capacity building programme ensures proper application of the nutrients and optimal use of on-farm nutrients. To further shape our ideas of the Fertile Grounds Initiative you are cordially invited to become involved.

Including spatial data in nutrient balance modelling on dairy farms

NASA Astrophysics Data System (ADS)

van Leeuwen, Maricke; van Middelaar, Corina; Stoof, Cathelijne; Oenema, Jouke; Stoorvogel, Jetse; de Boer, Imke

2017-04-01

The Annual Nutrient Cycle Assessment (ANCA) calculates the nitrogen (N) and phosphorus (P) balance at a dairy farm, while taking into account the subsequent nutrient cycles of the herd, manure, soil and crop components. Since January 2016, Dutch dairy farmers are required to use ANCA in order to increase understanding of nutrient flows and to minimize nutrient losses to the environment. A nutrient balance calculates the difference between nutrient inputs and outputs. Nutrients enter the farm via purchased feed, fertilizers, deposition and fixation by legumes (nitrogen), and leave the farm via milk, livestock, manure, and roughages. A positive balance indicates to which extent N and/or P are lost to the environment via gaseous emissions (N), leaching, run-off and accumulation in soil. A negative balance indicates that N and/or P are depleted from soil. ANCA was designed to calculate average nutrient flows on farm level (for the herd, manure, soil and crop components). ANCA was not designed to perform calculations of nutrient flows at the field level, as it uses averaged nutrient inputs and outputs across all fields, and it does not include field specific soil characteristics. Land management decisions, however, such as the level of N and P application, are typically taken at the field level given the specific crop and soil characteristics. Therefore the information that ANCA provides is likely not sufficient to support farmers' decisions on land management to minimize nutrient losses to the environment. This is particularly a problem when land management and soils vary between fields. For an accurate estimate of nutrient flows in a given farming system that can be used to optimize land management, the spatial scale of nutrient inputs and outputs (and thus the effect of land management and soil variation) could be essential. Our aim was to determine the effect of the spatial scale of nutrient inputs and outputs on modelled nutrient flows and nutrient use efficiencies at Dutch dairy farms. We selected two dairy farms located on cover sands in the Netherlands. One farm was located on relatively homogeneous soil type, and one on many different soil types within the sandy soils. A full year of data of N and P inputs and outputs on farm and field level were provided by the farmers, including field level yields, yield composition, manure composition, degree of grazing and degree of mowing. Soil heterogeneity was defined as the number of soil units within the farm corrected for surface area, and quantified from the Dutch 1:50.000 soil map. N and P balances at farm and field level were determined, as well as differences in nutrient use efficiency, leaching, and N emission. We will present the effect of the spatial scale on nutrient balance analysis and discuss to which degree any differences are caused by within-farm land management and soil variation. This study highlights to which extent within-farm land management and soil variation should be taken into account when modelling nutrient flows and nutrient use efficiencies at farm level, to contribute to field-based decision making for improved land management.

Sewage impacts coral reefs at multiple levels of ecological organization.

PubMed

Reopanichkul, Pasinee; Schlacher, Thomas A; Carter, R W; Worachananant, Suchai

2009-09-01

Against a backdrop of rising sea temperatures and ocean acidification which pose global threats to coral reefs, excess nutrients and turbidity continue to be significant stressors at regional and local scales. Because interventions usually require local data on pollution impacts, we measured ecological responses to sewage discharges in Surin Marine Park, Thailand. Wastewater disposal significantly increased inorganic nutrients and turbidity levels, and this degradation in water quality resulted in substantial ecological shifts in the form of (i) increased macroalgal density and species richness, (ii) lower cover of hard corals, and (iii) significant declines in fish abundance. Thus, the effects of nutrient pollution and turbidity can cascade across several levels of ecological organization to change key properties of the benthos and fish on coral reefs. Maintenance or restoration of ecological reef health requires improved wastewater management and run-off control for reefs to deliver their valuable ecosystems services.

Spatiotemporal patterns of livestock manure nutrient production in the conterminous United States from 1930 to 2012.

PubMed

Yang, Qichun; Tian, Hanqin; Li, Xia; Ren, Wei; Zhang, Bowen; Zhang, Xuesong; Wolf, Julie

2016-01-15

Manure nitrogen (N) and phosphorus (P) from livestock husbandry are important components of terrestrial biogeochemical cycling. Assessment of the impacts of livestock manure on terrestrial biogeochemistry requires a compilation and analysis of spatial and temporal patterns of manure nutrients. In this study, we reconstructed county-level manure nutrient data of the conterminous United States (U.S.) in 4- to 5-year increments from 1930 to 2012. Manure N and P were 5.8 9 ± 0.64 Tg N yr.(-1) (Mean ± Standard Deviation) and 1.73 ± 0.29 Tg Pyr.(-1) (1 Tg = 10(12)g), and increased by 46% and 92% from 1930 to 2012, respectively. Prior to 1970, manure provided more N to the U.S. lands than chemical fertilizer use. Since 1970, however, increasing chemical N fertilizer use has exceeded manure N production. Manure was the primary P source in the U.S. during 1930-1969 and 1987-2012, but was lower than P fertilizer use in 1974, 1978, and 1982. High-nutrient-production regions shifted towards eastern and western areas of the U.S. Decreasing small farms and increasing Concentrated Animal Feeding Operations (CAFOs) induced concentrated spatial patterns in manure nutrient loads. Counties with cattle or poultry as the primary manure nutrient contributors expanded significantly from 1930 to 2012, whereas regions with sheep and hog as the primary contributors decreased. We identified regions facing environmental threats associated with livestock farming. Effective management of manure should consider the impacts of CAFOs in manure production, and changes in livestock population structure. The long-term county-level manure nutrient dataset provides improved spatial and temporal information on manure nutrients in the U.S. This dataset is expected to help advance research on nutrient cycling, ammonia volatilization, greenhouse gas (GHG) emissions from livestock husbandry, recovery and reuse of manure nutrients, and impacts of livestock feeding on human health in the context of global change. Copyright © 2015 Elsevier B.V. All rights reserved.

Spatiotemporal patterns of livestock manure nutrient production in the conterminous United States from 1930 to 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qichun; Tian, Hanqin; Li, Xia

Manure nitrogen (N) and phosphorus (P) from livestock husbandry are important components of terrestrial biogeochemical cycling. Assessment of the impacts of livestock manure on terrestrial biogeochemistry requires a compilation and analysis of spatial and temporal patterns of manure nutrients. In this study, we reconstructed county-level manure nutrient data of the conterminous United States (U.S.) in 4- to 5-year increments from 1930 to 2012. Manure N and P were 5.89 +/- 0.64 Tg N yr.(-1) (Mean +/- Standard Deviation) and 1.73 +/- 0.29 Tg P yr.(-1) (1 Tg=10(12) g), and increased by 46% and 92% from 1930 to 2012, respectively. Priormore » to 1970, manure provided more N to the U.S. lands than chemical fertilizer use. Since 1970, however, increasing chemical N fertilizer use has exceeded manure N production. Manure was the primary P source in the U.S. during 1930-1969 and 1987-2012, but was lower than P fertilizer use in 1974, 1978, and 1982. High-nutrient-production regions shifted towards eastern and western areas of the U.S. Decreasing small farms and increasing Concentrated Animal Feeding Operations (CAFOs) induced concentrated spatial patterns in manure nutrient loads. Counties with cattle or poultry as the primary manure nutrient contributors expanded significantly from 1930 to 2012, whereas regions with sheep and hog as the primary contributors decreased. We identified regions facing environmental threats associated with livestock farming. Effective management of manure should consider the impacts of CAFOs inmanure production, and changes in livestock population structure. The long-term county-level manure nutrient dataset provides improved spatial and temporal information on manure nutrients in the U.S. This dataset is expected to help advance research on nutrient cycling, ammonia volatilization, greenhouse gas (GHG) emissions from livestock husbandry, recovery and reuse of manure nutrients, and impacts of livestock feeding on human health in the context of global change.« less

Methods for simulating nutritional requirement and response studies with all organisms to increase research efficiency.

PubMed

Vedenov, Dmitry; Alhotan, Rashed A; Wang, Runlian; Pesti, Gene M

2017-02-01

Nutritional requirements and responses of all organisms are estimated using various models representing the response to different dietary levels of the nutrient in question. To help nutritionists design experiments for estimating responses and requirements, we developed a simulation workbook using Microsoft Excel. The objective of the present study was to demonstrate the influence of different numbers of nutrient levels, ranges of nutrient levels and replications per nutrient level on the estimates of requirements based on common nutritional response models. The user provides estimates of the shape of the response curve, requirements and other parameters and observation to observation variation. The Excel workbook then produces 1-1000 randomly simulated responses based on the given response curve and estimates the standard errors of the requirement (and other parameters) from different models as an indication of the expected power of the experiment. Interpretations are based on the assumption that the smaller the standard error of the requirement, the more powerful the experiment. The user can see the potential effects of using one or more subjects, different nutrient levels, etc., on the expected outcome of future experiments. From a theoretical perspective, each organism should have some enzyme-catalysed reaction whose rate is limited by the availability of some limiting nutrient. The response to the limiting nutrient should therefore be similar to enzyme kinetics. In conclusion, the workbook eliminates some of the guesswork involved in designing experiments and determining the minimum number of subjects needed to achieve desired outcomes.

Temperature effects on stocks and stability of a phytoplankton-zooplankton model and the dependence on light and nutrients

USGS Publications Warehouse

Norberg, J.; DeAngelis, D.L.

1997-01-01

A model of a closed phytoplankton—zooplankton ecosystem was analyzed for effects of temperature on stocks and stability and the dependence of these effects on light and total nutrient concentration of the system. An analysis of the steady state equations showed that the effect of temperature on zooplankton and POM biomass was levelled when primary production is nutrient limited. Temperature increase had a generally negative effect on all biomasses at high nutrient levels due to increased maintenance costs. Nutrient limitation of net primary production is the main factor governing the effect of stocks and flows as well as the stability of the system. All components of the system, except for phytoplankton biomass, are proportional to net production and thus to the net effect of light on photosynthesis. However, temperature determines the slope of that relationship. The resilience of the system was measured by calculating the eigenvalues of the steady state. Under oligotrophic conditions, the system can be stable, but an increase in temperature can cause instability or a decrease in resilience. This conclusion is discussed in the face of recent models that take spatial heterogeneity into account and display far more stable behavior, in better agreement to empirical data. Using simulations, we found that the amplitude of fluctuations of the herbivore stock increases with temperature while the mean biomass and minimum values decrease in comparison with steady state predictions

Nutrient enrichment modifies temperature-biodiversity relationships in large-scale field experiments

PubMed Central

Wang, Jianjun; Pan, Feiyan; Soininen, Janne; Heino, Jani; Shen, Ji

2016-01-01

Climate effects and human impacts, that is, nutrient enrichment, simultaneously drive spatial biodiversity patterns. However, there is little consensus about their independent effects on biodiversity. Here we manipulate nutrient enrichment in aquatic microcosms in subtropical and subarctic regions (China and Norway, respectively) to show clear segregation of bacterial species along temperature gradients, and decreasing alpha and gamma diversity toward higher nutrients. The temperature dependence of species richness is greatest at extreme nutrient levels, whereas the nutrient dependence of species richness is strongest at intermediate temperatures. For species turnover rates, temperature effects are strongest at intermediate and two extreme ends of nutrient gradients in subtropical and subarctic regions, respectively. Species turnover rates caused by nutrients do not increase toward higher temperatures. These findings illustrate direct effects of temperature and nutrients on biodiversity, and indirect effects via primary productivity, thus providing insights into how nutrient enrichment could alter biodiversity under future climate scenarios. PMID:28000677

Nutrient enrichment modifies temperature-biodiversity relationships in large-scale field experiments.

PubMed

Wang, Jianjun; Pan, Feiyan; Soininen, Janne; Heino, Jani; Shen, Ji

2016-12-21

Climate effects and human impacts, that is, nutrient enrichment, simultaneously drive spatial biodiversity patterns. However, there is little consensus about their independent effects on biodiversity. Here we manipulate nutrient enrichment in aquatic microcosms in subtropical and subarctic regions (China and Norway, respectively) to show clear segregation of bacterial species along temperature gradients, and decreasing alpha and gamma diversity toward higher nutrients. The temperature dependence of species richness is greatest at extreme nutrient levels, whereas the nutrient dependence of species richness is strongest at intermediate temperatures. For species turnover rates, temperature effects are strongest at intermediate and two extreme ends of nutrient gradients in subtropical and subarctic regions, respectively. Species turnover rates caused by nutrients do not increase toward higher temperatures. These findings illustrate direct effects of temperature and nutrients on biodiversity, and indirect effects via primary productivity, thus providing insights into how nutrient enrichment could alter biodiversity under future climate scenarios.

Nutrient enrichment modifies temperature-biodiversity relationships in large-scale field experiments

NASA Astrophysics Data System (ADS)

Wang, Jianjun; Pan, Feiyan; Soininen, Janne; Heino, Jani; Shen, Ji

2016-12-01

Climate effects and human impacts, that is, nutrient enrichment, simultaneously drive spatial biodiversity patterns. However, there is little consensus about their independent effects on biodiversity. Here we manipulate nutrient enrichment in aquatic microcosms in subtropical and subarctic regions (China and Norway, respectively) to show clear segregation of bacterial species along temperature gradients, and decreasing alpha and gamma diversity toward higher nutrients. The temperature dependence of species richness is greatest at extreme nutrient levels, whereas the nutrient dependence of species richness is strongest at intermediate temperatures. For species turnover rates, temperature effects are strongest at intermediate and two extreme ends of nutrient gradients in subtropical and subarctic regions, respectively. Species turnover rates caused by nutrients do not increase toward higher temperatures. These findings illustrate direct effects of temperature and nutrients on biodiversity, and indirect effects via primary productivity, thus providing insights into how nutrient enrichment could alter biodiversity under future climate scenarios.

Food prices and poverty negatively affect micronutrient intakes in Guatemala.

PubMed

Iannotti, Lora L; Robles, Miguel; Pachón, Helena; Chiarella, Cristina

2012-08-01

Limited empirical evidence exists for how economic conditions affect micronutrient nutrition. We hypothesized that increasing poverty and rising food prices would reduce consumption of high-quality "luxury" foods, leading to an increased probability of inadequacy for several nutrients. The 2006 Guatemala National Living Conditions Survey was analyzed. First, energy and nutrient intakes and adequacy levels were calculated. Second, the income-nutrient relationships were investigated by assessing disparities in intakes, determining income-nutrient elasticities, and modeling nutrient intakes by reductions in income. Third, the food price-nutrient relationships were explored through determination of price-nutrient elasticities and modeling 2 price scenarios: an increase in food prices similar in magnitude to the food price crisis of 2007-2008 and a standardized 10% increase across all food groups. Disparities in nutrient intakes were greatest for vitamin B-12 (0.38 concentration index) and vitamin A (0.30 concentration index); these nutrients were highly and positively correlated with income (r = 0.22-0.54; P < 0.05). Although the baseline probability of inadequacy was highest for vitamin B-12 (83%), zinc showed the greatest increase in probability of inadequacy as income was reduced, followed by folate and vitamin A. With rising food prices, zinc intake was most acutely affected under both scenarios (P < 0.05) and folate intake in the poorest quintile (+7 percentage points) under the 10% scenario. Price-nutrient elasticities were highest for vitamin B-12 and the meat, poultry, and fish group (-0.503) and for folate and the legumes group (-0.343). The economic factors of food prices and income differentially influenced micronutrient intakes in Guatemala, notably zinc and folate intakes.

Effects of Souvenaid on plasma micronutrient levels and fatty acid profiles in mild and mild-to-moderate Alzheimer's disease.

PubMed

Rijpma, Anne; Meulenbroek, Olga; van Hees, Anneke M J; Sijben, John W C; Vellas, Bruno; Shah, Raj C; Bennett, David A; Scheltens, Philip; Olde Rikkert, Marcel G M

2015-01-01

Circulating levels of uridine, selenium, vitamins B12, E and C, folate, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been shown to be lower in patients with Alzheimer's disease (AD) than in healthy individuals. These low levels may affect disease pathways involved in synapse formation and neural functioning. Here, we investigated whether, and to what extent, circulating levels of micronutrients and fatty acids can be affected by oral supplementation with Souvenaid (containing a specific nutrient combination), using data derived from three randomized clinical trials (RCT) and an open-label extension (OLE) study with follow-up data from 12 to 48 weeks. Subjects with mild (RCT1, RCT2) or mild-to-moderate AD (RCT3) received active or control product once daily for 12-24 weeks or active product during the 24-week OLE following RCT2 (n = 212-527). Measurements included plasma levels of B vitamins, choline, vitamin E, selenium, uridine and homocysteine and proportions of DHA, EPA and total n-3 long-chain polyunsaturated fatty acids in plasma and erythrocytes. Between-group comparisons were made using t tests or non-parametric alternatives. We found that 12-24-week active product intake increased plasma and/or erythrocyte micronutrients: uridine; choline; selenium; folate; vitamins B6, B12 and E; and fatty acid levels of DHA and EPA (all p < 0.001). In the OLE study, similar levels were reached in former control product/initial active product users, whereas 24-week continued active product intake showed no suggestion of a further increase in nutrient levels. These data show that circulating levels of nutrients known to be decreased in the AD population can be increased in patients with mild and mild-tomoderate AD by 24-48-week oral supplementation with Souvenaid. In addition, to our knowledge, this is the first report of the effects of sustained dietary intake of uridine monophosphate on plasma uridine levels in humans. Uptake of nutrients is observed within 6 weeks, and a plateau phase is reached for most nutrients during prolonged intake, thus increasing the availability of precursors and cofactors in the circulation that may be used for the formation and function of neuronal membranes and synapses in the brain.

Mechanisms for Success after Long-term Nutrient Enrichment in a Boreal Forest Understory

PubMed Central

Grainger, Tess Nahanni; Turkington, Roy

2013-01-01

Global levels of reactive nitrogen are predicted to rise in the coming decades as a result of increased deposition from the burning of fossil fuels and the large-scale conversion of nitrogen into a useable form for agriculture. Many plant communities respond strongly to increases in soil nitrogen, particularly in northern ecosystems where nitrogen levels are naturally very low. An experiment in northern Canada that was initiated in 1990 has been investigating the effects of long-term nutrient enrichment (fertilizer added annually) on a boreal forest understory community. We used this experiment to investigate why some species increase in abundance under nutrient enrichment whereas others decline. We focused on four species that differed in their responses to fertilization: Mertensia paniculata and Epilobium angustifolium increased in abundance, Achillea millefolium remained relatively constant and Festuca altaica declined. We hypothesized that the two species that were successful in the new high-nutrient, light-limited environment would be taller, have higher specific leaf area, change phenology by growing earlier in the season and be more morphologically plastic than their less successful counterparts. We compared plant height, specific leaf area, growth spurt date and allocation to leaves in plants grown in control and fertilized plots. We demonstrated that each of the two species that came to dominate fertilized plots has a different combination of traits and responses that likely gave them a competitive advantage; M. paniculata has the highest specific leaf area of the four species whereas E. angustifolium is tallest and exhibits morphological plasticity when fertilized by increasing biomass allocation to leaves. These results indicate that rather than one strategy determining success when nutrients become available, a variety of traits and responses may contribute to a species' ability to persist in a nutrient-enriched boreal forest understory. PMID:23573298

Density-dependent regulation of growth of BSC-1 cells in cell culture: Control of growth by low molecular weight nutrients

PubMed Central

Holley, Robert W.; Armour, Rosemary; Baldwin, Julia H.

1978-01-01

BSC-1 cells, epithelial cells of African green monkey kidney origin, show pronounced density-dependent regulation of growth in cell culture. Growth of the cells is rapid to a density of approximately 1.5 × 105 cells/per cm2 in Dulbecco-modified Eagle's medium supplemented with 10% calf serum. Above this “saturation density,” growth is much slower. It has been found that the glucose concentration in the culture medium is important in determining the “saturation density.” If the glucose concentration is increased 4-fold, the “saturation density” increases approximately 50%. Reduction of the “saturation density” of BSC-1 cells is also possible by decreasing the concentrations of low molecular weight nutrients in the culture medium. In medium supplemented with 0.1% calf serum, decreasing the concentrations of all of the organic constituents of the medium, from the high levels present in Dulbecco-modified Eagle's medium to concentrations near physiological levels, decreases the “saturation density” by approximately half. The decreased “saturation density” is not the result of lowering the concentration of any single nutrient but rather results from reduction of the concentrations of several nutrients. When the growth of BSC-1 cells is limited by low concentrations of all of the nutrients, some stimulation of growth results from increasing, separately, the concentrations of individual groups of nutrients, but the best growth stimulation is obtained by increasing the concentrations of all of the nutrients. The “wound healing” phenomenon, one manifestation of density-dependent regulation of growth in cell culture, is abolished by lowering the concentration of glutamine in the medium. Density-dependent regulation of growth of BSC-1 cells in cell culture thus appears to be a complex phenomenon that involves an interaction of nutrient concentrations with other regulatory factors. PMID:272650

Interactions among irradiance, nutrients, and herbivores constrain a stream algal community.

PubMed

Rosemond, A D

1993-07-01

Using stream-side, flow-through channels, I tested for the effects of nutrients (NU) (nitrogen plus phosphorus), irradiance (L), and snail grazing (G) on a benthic algal community in a small, forested stream. Grazed communities were-dominated by a chlorophyte (basal cells ofStigeoclonium) and a cyanophyte (Chamaesiphon investiens), whereas ungrazed communities were comprised almost entirely of diatoms, regardless of nutrient and light levels. Snails maintained low algal biomass in all grazed treatments, presumably by consuming increased algal production in treatments to which L and NU were increased. When nutrients were increased, cellular nutrient content increased under ambient conditions (shaded, grazed) and biomass and productivity increased when snails were removed and light was increased. Together, nutrients and light had positive effects and grazing had negative effects on biomass (chlorophylla, AFDM, algal biovolume) and chlorophyll-and areal-specific productivity in ANOVAs. However, in most cases, only means from treatments in which all three factors were manipulated (ungrazed, +NU&L treatments) were significantly different from controls; effects of single factors were generally undetectable. These results indicate that all three factors simultaneously limited algal biomass and productivity in this stream during the summer months. Additionally, the effects of these factors in combination were in some cases different from the effects of single factors. For example, light had slight negative effects on some biomass parameters when added at ambient snail densities and nutrient concentrations, but had strong positive effects in conjunction with nutrient addition and snail removal. This study demonstrates that algal biomass and productivity can be under multiple constraints by irradiance, nutrients, and herbivores and indicates the need to employ multifactor experiments to test for such interactive effects.

The effect of nitrate and phosphate availability on Emiliania huxleyi (NZEH) physiology under different CO2 scenarios.

PubMed

Rouco, Mónica; Branson, Oscar; Lebrato, Mario; Iglesias-Rodríguez, M Débora

2013-01-01

Growth and calcification of the marine coccolithophorid Emiliania huxleyi is affected by ocean acidification and macronutrients limitation and its response varies between strains. Here we investigated the physiological performance of a highly calcified E. huxleyi strain, NZEH, in a multiparametric experiment. Cells were exposed to different CO2 levels (ranging from 250 to 1314 μatm) under three nutrient conditions [nutrient replete (R), nitrate limited (-N), and phosphate limited (-P)]. We focused on calcite and organic carbon quotas and on nitrate and phosphate utilization by analyzing the activity of nitrate reductase (NRase) and alkaline phosphatase (APase), respectively. Particulate inorganic (PIC) and organic (POC) carbon quotas increased with increasing CO2 under R conditions but a different pattern was observed under nutrient limitation. The PIC:POC ratio decreased with increasing CO2 in nutrient limited cultures. Coccolith length increased with CO2 under all nutrient conditions but the coccosphere volume varied depending on the nutrient treatment. Maximum APase activity was found at 561 μatm of CO2 (pH 7.92) in -P cultures and in R conditions, NRase activity increased linearly with CO2. These results suggest that E. huxleyi's competitive ability for nutrient uptake might be altered in future high-CO2 oceans. The combined dataset will be useful in model parameterizations of the carbon cycle and ocean acidification.

WATER LEVEL AND OXYGEN DELIVERY/UTILIZATION IN POROUS SALT MARSH SEDIMENTS

EPA Science Inventory

Increasing terrestrial nutrient inputs to coastal waters is a global water quality issue worldwide, and salt marshes may provide a valuable nutrient buffer, either by direct removal or by smoothing out pulse inputs between sources and sensitive estuarine habitats. A major challen...

A gradient of nutrient enrichment reveals nonlinear impacts of fertilization on Arctic plant diversity and ecosystem function.

PubMed

Prager, Case M; Naeem, Shahid; Boelman, Natalie T; Eitel, Jan U H; Greaves, Heather E; Heskel, Mary A; Magney, Troy S; Menge, Duncan N L; Vierling, Lee A; Griffin, Kevin L

2017-04-01

Rapid environmental change at high latitudes is predicted to greatly alter the diversity, structure, and function of plant communities, resulting in changes in the pools and fluxes of nutrients. In Arctic tundra, increased nitrogen (N) and phosphorus (P) availability accompanying warming is known to impact plant diversity and ecosystem function; however, to date, most studies examining Arctic nutrient enrichment focus on the impact of relatively large (>25x estimated naturally occurring N enrichment) doses of nutrients on plant community composition and net primary productivity. To understand the impacts of Arctic nutrient enrichment, we examined plant community composition and the capacity for ecosystem function (net ecosystem exchange, ecosystem respiration, and gross primary production) across a gradient of experimental N and P addition expected to more closely approximate warming-induced fertilization. In addition, we compared our measured ecosystem CO 2 flux data to a widely used Arctic ecosystem exchange model to investigate the ability to predict the capacity for CO 2 exchange with nutrient addition. We observed declines in abundance-weighted plant diversity at low levels of nutrient enrichment, but species richness and the capacity for ecosystem carbon uptake did not change until the highest level of fertilization. When we compared our measured data to the model, we found that the model explained roughly 30%-50% of the variance in the observed data, depending on the flux variable, and the relationship weakened at high levels of enrichment. Our results suggest that while a relatively small amount of nutrient enrichment impacts plant diversity, only relatively large levels of fertilization-over an order of magnitude or more than warming-induced rates-significantly alter the capacity for tundra CO 2 exchange. Overall, our findings highlight the value of measuring and modeling the impacts of a nutrient enrichment gradient, as warming-related nutrient availability may impact ecosystems differently than single-level fertilization experiments.

Beaver Ponds Increase Methylmercury and Nutrients Concentrations in Canadian Shield Streams

NASA Astrophysics Data System (ADS)

Roy, V.; Amyot, M.; Carignan, R.

2007-12-01

Beaver populations and the number of beaver dams are currently increasing in many Canadian regions. Since natural and anthropogenic impoundments have historically been identified as sources of the potent neurotoxin methylmercury (MeHg), beaver dams could also increase MeHg levels in streams. During summer 2006, we collected water samples upstream and downstream from twenty beaver dams of the Laurentians, located on the Canadian Shield. Samples were analysed for total Hg, MeHg and other chemical variables including DOC, TP, TDP, TN, and major ions. Significant increases of nutrients (DOC, TP, TDP, TN) and ammonium concentrations and depletions of oxygen, nitrate and sulphate concentrations between inlet and outlet show that beaver ponds provide environmental conditions that can favour methylation of inorganic mercury. Heterogeneity of the ratio MeHg/THg at the outlet among our sites was well explained by the estimated age of the impoundment, with methylation capacity of beaver ponds decreasing with age. Further, the geographic location of beaver ponds influenced water chemistry at the outlet, as we observed a dichotomy between northern and southern sites; these differences were based mainly on forest composition. On average, beaver impoundments increased MeHg concentrations by 5.7 fold, total Hg concentrations by 1.6 fold and nutrients concentrations by 2-3 fold. Overall, our results suggest that beaver dams may considerably increase MeHg and nutrients levels in downstream ecosystems. The impact of beavers on the cycling of contaminants and nutrients in boreal watersheds should therefore be considered in the management of their populations.

Effect of nutrient density on production performance, egg quality and humoral immune response of brown laying (Dahlem Red) hens in the tropics.

PubMed

Panda, Arun Kumar; Rao, Savaram Venkata Rama; Raju, Mantena Venkata Lakshmi Narasimha; Niranjan, Matam; Reddy, Maddula Ramkoti

2012-02-01

A study was conducted to evaluate the effect of various concentrations of metabolizable energy (ME) with graded incremental levels of crude protein (CP) and essential amino acids (lysine and methionine) on production performance, egg quality and humoral immune response of Dahlem Red laying hens. Four experimental diets based on maize-soybean meal-deoiled rice bran were prepared. Diet 1 was fed as a control diet containing 2,600 kcal ME/kg, 15% CP, 0.75% Lys and 0.36% Met, and in the other three diets (D2, D3 and D4), concentrations of the above nutrients were increased by 2.5%, 5.0% and 7.5%, respectively. The levels of Ca (3.5%) and available P (0.32) were constant in all the diets. Each diet was offered ad libitum from 28 to 40 weeks of age to eight replicates containing six birds in each replicate. The egg production, egg weight and egg mass (in grams of egg per hen per day) were not affected by increasing the nutrient density up to 7.5% (2,795 kcal ME/kg diet) compared to the control group (2,600 ME/kg diet). However, feed consumption and feed efficiency (in grams of egg per gram of feed) were influenced by the variation in the nutrient density of diets. As the nutrient density increased by 5% (2,730 ME/kg diet), birds consumed significantly (P < 0.001) less feed. The birds in the 7.5% higher density group produced significantly (P < 0.05) higher egg mass per unit feed consumption compared to the control diet. Increasing nutrient density up to 7.5% had no effect on relative weight of albumen, yolk or shell. The Haugh unit, yolk colour and shell thickness were also not affected due to variation in the nutrient density. The humoral immune response measured at 34 and 40 weeks was progressively improved by increasing the nutrient density up to 5%. Increasing the nutrient density beyond 5% in the diet had no further influence on the humoral immune response. Based on the results of the present study, it can be concluded that Dahlem Red laying hens required 2,795 kcal/kg ME, 16% CP, 0.8% lysine and 0.4% methionine for eliciting optimum performance and immune response during 28 to 40 weeks of age.

Altered physiology, cell structure, and gene expression of Theobroma cacao seedlings subjected to Cu toxicity.

PubMed

Souza, Vânia L; de Almeida, Alex-Alan F; Souza, Jadiel de S; Mangabeira, Pedro A O; de Jesus, Raildo M; Pirovani, Carlos P; Ahnert, Dário; Baligar, Virupax C; Loguercio, Leandro L

2014-01-01

Seedlings of Theobroma cacao CCN 51 genotype were grown under greenhouse conditions and exposed to increasing concentrations of Cu (0.005, 1, 2, 4, 8, 16, and 32 mg Cu L(-1)) in nutrient solution. When doses were equal or higher than 8 mg Cu L(-1), after 24 h of treatment application, leaf gas exchange was highly affected and changes in chloroplasts thylakoids of leaf mesophyll cells and plasmolysis of cells from the root cortical region were observed. In addition, cell membranes of roots and leaves were damaged. In leaves, 96 h after treatments started, increases in the percentage of electrolyte leakage through membranes were observed with increases of Cu in the nutrient solution. Moreover, there was an increase in the concentration of thiobarbituric acid-reactive substances in roots due to lipid peroxidation of membranes. Chemical analysis showed that increases in Cu concentrations in vegetative organs of T. cacao increased with the increase of the metal in the nutrient solution, but there was a greater accumulation of Cu in roots than in shoots. The excess of Cu interfered in the levels of Mn, Zn, Fe, Mg, K, and Ca in different organs of T. cacao. Analysis of gene expression via RTq-PCR showed increased levels of MT2b, SODCyt, and PER-1 expression in roots and of MT2b, PSBA, PSBO, SODCyt, and SODChI in leaves. Hence, it was concluded that Cu in nutrient solution at doses equal or above 8 mg L(-1) significantly affected leaf gas exchange, cell ultrastructure, and transport of mineral nutrients in seedlings of this T. cacao genotype.

NovaSil clay does not affect the concentrations of vitamins A and E and nutrient minerals in serum samples from Ghanaians at high risk for aflatoxicosis.

PubMed

Afriyie-Gyawu, E; Wang, Z; Ankrah, N-A; Xu, L; Johnson, N M; Tang, L; Guan, H; Huebner, H J; Jolly, P E; Ellis, W O; Taylor, R; Brattin, B; Ofori-Adjei, D; Williams, J H; Wang, J-S; Phillips, T D

2008-07-01

To assess the potential interference of NovaSil (NS) clay with micronutrients in humans, vitamins A and E and minerals (15 nutrient and 15 non-nutrient minerals) were measured in serum samples from a 3-month intervention trial with NS. Participants (n = 177) were randomly divided into three groups that received 3.0 g NS day(-1) (high dose, HD), 1.5 g NS day(-1) (low dose, LD), or placebo (PL). Levels of vitamins A and E in serum were comparable among the three study groups at baseline, 1 month and 3 months of NS intervention. Gender-stratified non-parametric mixed-effect model analysis showed no significant effects of dose and dose-time interaction for levels of vitamins A and E. A significant time effect was detected; however, it was limited to an increase in vitamin E in the male participants over the course of the study. No significant differences were found in levels of the nutrient and non-nutrient minerals between the HD and PL groups at baseline and 3 months of NS intervention, except for strontium levels. Strontium was significantly increased (p < 0.001) in the HD group (male = 113.65 +/- 28.00 microg l(-1); female = 116.40 +/- 24.26 microg l(-1)) compared with the PL group (male = 83.55 +/- 39.90 microg l(-1); female = 90.47 +/- 25.68 microg l(-1)) following the 3-month intervention with NS. These results, combined with safety and efficacy data, confirm that NS clay is highly effective in reducing aflatoxin exposure and acts as a selective enterosorbent that does not affect the serum concentrations of important vitamins and nutrient minerals in humans.

Nutrient dynamics and budget with the surface water-groundwater interaction in the tidal river in Japan

NASA Astrophysics Data System (ADS)

Onodera, S.; Saito, M.; Maruyama, Y.; Jin, G.; Miyaoka, K.; Shimizu, Y.

2013-12-01

In coastal megacities, sever groundwater depression and water pollution occurred. These impacts affected to river environment change. Especially, the river mouth area has been deposited the polluted matters. These areas have characteristics of water level fluctuation which causes river water-groundwater interaction and the associated change in dynamics of nutrients. However, these effects on the nutrient transport in tidal reaches and nutrient load to the sea have not been fully evaluated in previous studies. Therefore, we aimed to clarify the characteristics of the nutrient transport with the river water-groundwater interaction in the tidal river of Osaka metropolitan city. We conducted the field survey from the river mouth to the 7km upstream area of Yamato River, which has a length of 68km and a watershed area of 1070 km2. Spatial variations in radon (222Rn) concentrations and the difference of hydraulic potential between river waters and the pore waters suggest that the groundwater discharges to the river channel in the upstream area. In contrast, the river water recharged into the groundwater near the river mouth area. It may be caused by the lowering of groundwater level associated with the excess abstraction of groundwater in the urban area. The result also implies the seawater intrusion would accelerate the salinization of groundwater. The spatial and temporal variations in nutrient concentrations indicate that nitrate-nitrogen (NO3-N) concentrations changed temporally and it negative correlated with dissolved organic nitrogen (DON) concentrations. Inorganic phosphorous (PO4-P) concentrations showed the increasing trend with the increase of the river water level. Based on the mass balance, nutrient reproduction from the river bed was suggested in tidal reach. That was estimated to be 10 % of total nitrogen and 3% of phosphorus loads from the upstream.

Bacterial and Phytoplankton Responses to Nutrient Amendments in a Boreal Lake Differ According to Season and to Taxonomic Resolution

PubMed Central

Peura, Sari; Eiler, Alexander; Hiltunen, Minna; Nykänen, Hannu; Tiirola, Marja; Jones, Roger I.

2012-01-01

Nutrient limitation and resource competition in bacterial and phytoplankton communities may appear different when considering different levels of taxonomic resolution. Nutrient amendment experiments conducted in a boreal lake on three occasions during one open water season revealed complex responses in overall bacterioplankton and phytoplankton abundance and biovolume. In general, bacteria were dominant in spring, while phytoplankton was clearly the predominant group in autumn. Seasonal differences in the community composition of bacteria and phytoplankton were mainly related to changes in observed taxa, while the differences across nutrient treatments within an experiment were due to changes in relative contributions of certain higher- and lower-level phylogenetic groups. Of the main bacterioplankton phyla, only Actinobacteria had a treatment response that was visible even at the phylum level throughout the season. With increasing resolution (from 75 to 99% sequence similarity) major responses to nutrient amendments appeared using 454 pyrosequencing data of 16S rRNA amplicons. This further revealed that OTUs (defined by 97% sequence similarity) annotated to the same highly resolved freshwater groups appeared to occur during different seasons and were showing treatment-dependent differentiation, indicating that OTUs within these groups were not ecologically coherent. Similarly, phytoplankton species from the same genera responded differently to nutrient amendments even though biovolumes of the majority of taxa increased when both nitrogen and phosphorus were added simultaneously. The bacterioplankton and phytoplankton community compositions showed concurrent trajectories that could be seen in synchronous succession patterns over the season. Overall, our data revealed that the response of both communities to nutrient changes was highly dependent on season and that contradictory results may be obtained when using different taxonomic resolutions. PMID:22715392

Simultaneous remediation of nutrients from liquid anaerobic digestate and municipal wastewater by the microalga Scenedesmus sp. AMDD grown in continuous chemostats.

PubMed

Dickinson, K E; Bjornsson, W J; Garrison, L L; Whitney, C G; Park, K C; Banskota, A H; McGinn, P J

2015-01-01

The primary aim of this study was to investigate the capacity of a microalga, Scenedesmus sp. AMDD, to remediate nutrients from municipal wastewater, either as the sole nutrient source or after blending with wastewater obtained from the anaerobic digestion of swine manure. A complimentary aim was to study and define the effects of these wastewaters on microalgal growth, biomass productivity and composition which have important implications for a commercial biofuels production system. A microalga, Scenedesmus sp. AMDD, was grown in continuous chemostats in municipal wastewater or wastewater supplemented with 1·6× or 2·4× higher levels of nitrogen (N) obtained through supplementation with anaerobic digestates. Biomass productivity increased with increasing nutrient supplementation, but was limited by light at high cell densities. Cellular quotas of carbon (C), nitrogen and phosphorus (P) all increased in direct proportion to their concentrations in the combined wastewaters. At higher cell densities, total carbohydrate decreased while protein increased. Fatty acid content remained relatively constant. Under high nutrient levels, the fatty acid profiles contained a higher concentration of polyunsaturated fatty acids at the expense of monounsaturated fatty acids. Chlorophyll a was 2·5 times greater in the treatment of greatest nutrient supplementation compared to the treatment with the least. Ammonium (NH4(+)) and phosphate (PO4(3-)) were completely removed by algal growth in all treatments and with maximal removal rates of 41·2 mg N l(-1) d(-1) and 6·7 mg P l(-1) d(-1) observed in wastewater amended with 2·4× higher N level. The study is the first to report stable, long-term continuous algal growth and productivity obtained by combining wastewaters of different sources. The study is supported by detailed analyses of the composition of the cultivated biomass and links composition to the nutrient and light availabilities in the cultures. Simultaneous remediation of these wastes by algal growth is discussed as a strategy for the valorization of the biomass. © 2014 Her Majesty the Queen in Right of Canada © 2014 The Society for Applied Microbiology. Reproduced with the permission of the Minister of Industry.

Nutrient dynamics in tropical rivers, estuarine-lagoons, and coastal ecosystems along the eastern Hainan Island

NASA Astrophysics Data System (ADS)

Li, R. H.; Liu, S. M.; Li, Y. W.; Zhang, G. L.; Ren, J. L.; Zhang, J.

2013-06-01

Nutrient dynamics were studied along the eastern Hainan Island based on field observations during 2006-2009, to understand nutrient biogeochemical processes and to have an overview of human perturbations on coastal ecosystems in this tropical region. The concentrations of nutrients in the rivers had seasonal variations enriched with dissolved inorganic nitrogen (DIN). High riverine concentrations of nitrate were mainly originated from agricultural fertilizer input. The ratios of DIN : PO43- ranged from 37 to 1063, suggesting preferential PO43- relative to nitrogen in the rivers. The areal yields of dissolved silicate (DSi) varied from 76 to 448 × 103 mol km-2 yr-1 due to erosion over the drainage area, inducing high levels of DSi among worldwide tropical systems. Aquaculture ponds contained high concentrations of NH4+ (up to 157 μM) and DON (up to 130 μM). Particulate phosphorus concentrations (0.5 ∼1.4 μM) were in lower level comparied with estuaries around the world. Particulate silicate levels in rivers and lagoons were lower than global average level. Nutrient biogeochemistry in coastal areas were affected by human activities (e.g. aquaculture, agriculture), as well as natural events such as typhoon. Nutrient concentrations were low because open sea water dispersed land-derived nutrients. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes would be magnified by estuarine processes (e.g. regeneration, desorption) in the Wenchanghe/Wenjiaohe Estuary, Wanquan River estuary, and the Laoyehai Lagoon except in the Xiaohai Lagoon. Riverine and groundwater input were the major sources of nutrients to the Xiaohai Lagoon and the Laiyehai Lagoon, respectively. Riverine input and aquaculture effluent were the major sources of nutrients to the eastern coastal of Hainan Island. Nutrient inputs to the coastal ecosystem can be increased by typhoon-induced runoff of rainwater, and phytoplankton bloom in the sea would be caused.

Evaluation of a combined macrophyte-epiphyte bioassay for assessing nutrient enrichment in the Portneuf River, Idaho, USA.

PubMed

Ray, Andrew M; Mebane, Christopher A; Raben, Flint; Irvine, Kathryn M; Marcarelli, Amy M

2014-07-01

We describe and evaluate a laboratory bioassay that uses Lemna minor L. and attached epiphytes to characterize the status of ambient and nutrient-enriched water from the Portneuf River, Idaho. Specifically, we measured morphological (number of fronds, longest surface axis, and root length) and population-level (number of plants and dry mass) responses of L. minor and community-level (ash-free dry mass [AFDM] and chlorophyll a [Chl a]) responses of epiphytes to nutrient enrichment. Overall, measures of macrophyte biomass and abundance increased with increasing concentrations of dissolved phosphorus (P) and responded more predictably to nutrient enrichment than morphological measures. Epiphyte AFDM and Chl a were also greatest in P-enriched water; enrichments of N alone produced no measurable epiphytic response. The epiphyte biomass response did not directly mirror macrophyte biomass responses, illustrating the value of a combined macrophyte-epiphyte assay to more fully evaluate nutrient management strategies. Finally, the most P-enriched waters not only supported greater standing stocks of macrophyte and epiphytes but also had significantly higher water column dissolved oxygen and dissolved organic carbon concentrations and a lower pH. Advantages of this macrophyte-epiphyte bioassay over more traditional single-species assays include the use of a more realistic level of biological organization, a relatively short assay schedule (~10 days), and the inclusion of multiple biological response and water-quality measures.

Evaluation of a combined macrophyte–epiphyte bioassay for assessing nutrient enrichment in the Portneuf River, Idaho, USA

USGS Publications Warehouse

Ray, Andrew M.; Mebane, Christopher A.; Raben, Flint; Irvine, Kathryn M.; Marcarelli, Amy M.

2014-01-01

We describe and evaluate a laboratory bioassay that uses Lemna minor L. and attached epiphytes to characterize the status of ambient and nutrient-enriched water from the Portneuf River, Idaho. Specifically, we measured morphological (number of fronds, longest surface axis, and root length) and population-level (number of plants and dry mass) responses of L. minor and community-level (ash-free dry mass [AFDM] and chlorophyll a [Chl a]) responses of epiphytes to nutrient enrichment. Overall, measures of macrophyte biomass and abundance increased with increasing concentrations of dissolved phosphorus (P) and responded more predictably to nutrient enrichment than morphological measures. Epiphyte AFDM and Chl a were also greatest in P-enriched water; enrichments of N alone produced no measurable epiphytic response. The epiphyte biomass response did not directly mirror macrophyte biomass responses, illustrating the value of a combined macrophyte–epiphyte assay to more fully evaluate nutrient management strategies. Finally, the most P-enriched waters not only supported greater standing stocks of macrophyte and epiphytes but also had significantly higher water column dissolved oxygen and dissolved organic carbon concentrations and a lower pH. Advantages of this macrophyte–epiphyte bioassay over more traditional single-species assays include the use of a more realistic level of biological organization, a relatively short assay schedule (~10 days), and the inclusion of multiple biological response and water-quality measures.

Impact of Temperature and Nutrients on Carbon: Nutrient Tissue Stoichiometry of Submerged Aquatic Plants: An Experiment and Meta-Analysis.

PubMed

Velthuis, Mandy; van Deelen, Emma; van Donk, Ellen; Zhang, Peiyu; Bakker, Elisabeth S

2017-01-01

Human activity is currently changing our environment rapidly, with predicted temperature increases of 1-5°C over the coming century and increased nitrogen and phosphorus inputs in aquatic ecosystems. In the shallow parts of these ecosystems, submerged aquatic plants enhance water clarity by resource competition with phytoplankton, provide habitat, and serve as a food source for other organisms. The carbon:nutrient stoichiometry of submerged aquatic plants can be affected by changes in both temperature and nutrient availability. We hypothesized that elevated temperature leads to higher carbon:nutrient ratios through enhanced nutrient-use efficiency, while nutrient addition leads to lower carbon:nutrient ratios by the luxurious uptake of nutrients. We addressed these hypotheses with an experimental and a meta-analytical approach. We performed a full-factorial microcosm experiment with the freshwater plant Elodea nuttallii grown at 10, 15, 20, and 25°C on sediment consisting of pond soil/sand mixtures with 100, 50, 25, and 12.5% pond soil. To address the effect of climatic warming and nutrient addition on the carbon:nutrient stoichiometry of submerged freshwater and marine plants we performed a meta-analysis on experimental studies that elevated temperature and/or added nutrients (nitrogen and phosphorus). In the microcosm experiment, C:N ratios of Elodea nuttallii decreased with increasing temperature, and this effect was most pronounced at intermediate nutrient availability. Furthermore, higher nutrient availability led to decreased aboveground C:P ratios. In the meta-analysis, nutrient addition led to a 25, 22, and 16% reduction in aboveground C:N and C:P ratios and belowground C:N ratios, accompanied with increased N content. No consistent effect of elevated temperature on plant stoichiometry could be observed, as very few studies were found on this topic and contrasting results were reported. We conclude that while nutrient addition consistently leads to decreased carbon:nutrient ratios, elevated temperature does not change submerged aquatic plant carbon:nutrient stoichiometry in a consistent manner. This effect is rather dependent on nutrient availability and may be species-specific. As changes in the carbon:nutrient stoichiometry of submerged aquatic plants can impact the transfer of energy to higher trophic levels, these results suggest that eutrophication may enhance plant consumption and decomposition, which could in turn have consequences for carbon sequestration.

Soil nutrient additions increase invertebrate herbivore abundances, but not herbivory, across three grassland systems.

PubMed

La Pierre, Kimberly J; Smith, Melinda D

2016-02-01

Resource availability may influence invertebrate communities, with important consequences for ecosystem function, such as biomass production. We assessed: (1) the effects of experimental soil nutrient additions on invertebrate abundances and feeding rates and (2) the resultant changes in the effects of invertebrates on aboveground plant biomass at three grassland sites spanning the North American Central Plains, across which plant tissue chemistry and biomass vary. Invertebrate communities and rates of herbivory were sampled within a long-term nutrient-addition experiment established at each site along the broad Central Plains precipitation gradient. Additionally, the effects of invertebrates on aboveground plant biomass were determined under ambient and elevated nutrient conditions. At the more mesic sites, invertebrate herbivore abundances increased and their per capita rate of herbivory decreased with nutrient additions. In contrast, at the semi-arid site where plant biomass is low and plant nutrient concentrations are high, invertebrate herbivore abundances did not vary and per capita rates of herbivory increased with nutrient additions. No change in the effect of invertebrate herbivores on aboveground plant biomass was observed at any of the sites. In sum, nutrient additions induced shifts in both plant biomass and leaf nutrient content, which altered invertebrate abundances and feeding rate. However, due to the inverse relationship between changes in herbivore abundance and per capita rates of herbivory, nutrient additions did not alter the effect of invertebrates on aboveground biomass. Overall, we suggest that this inverse response of herbivore abundance and per capita feeding rate may buffer ecosystems against changes in invertebrate damage in response to fluctuations in nutrient levels.

Disentangling the impact of nutrient load and climate changes on Baltic Sea hypoxia and eutrophication since 1850

NASA Astrophysics Data System (ADS)

Meier, H. E. M.; Eilola, K.; Almroth-Rosell, E.; Schimanke, S.; Kniebusch, M.; Höglund, A.; Pemberton, P.; Liu, Y.; Väli, G.; Saraiva, S.

2018-06-01

In the Baltic Sea hypoxia has been increased considerably since the first oxygen measurements became available in 1898. In 2016 the annual maximum extent of hypoxia covered an area of the sea bottom of about 70,000 km2, comparable with the size of Ireland, whereas 150 years ago hypoxia was presumably not existent or at least very small. The general view is that the increase in hypoxia was caused by eutrophication due to anthropogenic riverborne nutrient loads. However, the role of changing climate, e.g. warming, is less clear. In this study, different causes of expanding hypoxia were investigated. A reconstruction of the changing Baltic Sea ecosystem during the period 1850-2008 was performed using a coupled physical-biogeochemical ocean circulation model. To disentangle the drivers of eutrophication and hypoxia a series of sensitivity experiments was carried out. We found that the decadal to centennial changes in eutrophication and hypoxia were mainly caused by changing riverborne nutrient loads and atmospheric deposition. The impacts of other drivers like observed warming and eustatic sea level rise were comparatively smaller but still important depending on the selected ecosystem indicator. Further, (1) fictively combined changes in air temperature, cloudiness and mixed layer depth chosen from 1904, (2) exaggerated increases in nutrient concentrations in the North Sea and (3) high-end scenarios of future sea level rise may have an important impact. However, during the past 150 years hypoxia would not have been developed if nutrient conditions had remained at pristine levels.

Light Is More Important Than Nutrient Ratios of Fertilization for Cymodocea nodosa Seedling Development.

PubMed

Alexandre, Ana; Silva, João; Santos, Rui

2018-01-01

Restoration of seagrass beds through seedlings is an alternative to the transplantation of adult plants that reduces the impact over donor areas and increases the genetic variability of restored meadows. To improve the use of Cymodocea nodosa seedlings, obtained from seeds germinated in vitro , in restoration programs, we investigated the ammonium and phosphate uptake rates of seedlings, and the synergistic effects of light levels (20 and 200 μmol quanta m -2 s -1 ) and different nitrogen to phosphorus molar ratios (40 μM N:10 μM P, 25 μM N:25 μM P, and 10 μM N:40 μM P) on the photosynthetic activity and growth of seedlings. The nutrient content of seedlings was also compared to the seed nutrient reserves to assess the relative importance of external nutrient uptake for seedling development. Eighty two percent of the seeds germinated after 48 days at a mean rate of 1.5 seeds per day. All seedlings under all treatments survived and grew during the 4 weeks of the experiment. Seedlings of C. nodosa acquired ammonium and phosphate from the incubation media while still attached to the seed, at rates of about twice of adult plants. The relevance of external nutrient uptake was further highlighted by the observation that seedlings' tissues were richer in nitrogen and phosphorus than non-germinated seeds. The uptake of ammonium followed saturation kinetics with a half saturation constant of 32 μM whereas the uptake of phosphate increased linearly with nutrient concentration within the range tested (5 - 100 μM). Light was more important than the nutrient ratio of fertilization for the successful development of the young seedlings. The seedlings' photosynthetic and growth rates were about 20% higher in the high light treatment, whereas different nitrogen to phosphorus ratios did not significantly affect growth. The photosynthetic responses of the seedlings to changes in the light level and their capacity to use external nutrient sources showed that seedlings of C. nodosa have the ability to rapidly acclimate to the surrounding light and nutrient environment while still attached to the seeds. C. nodosa seedlings experiencing fertilization under low light levels showed slightly enhanced growth if nourished with a balanced formulation, whereas a slight increase in growth was also observed with unbalanced formulations under a higher light level. Our results highlight the importance of high light availability at the seedling restoration sites.

Influence of catchment land cover on stoichiometry and stable isotope compositions of basal resources and macroinvertebrate consumers in headwater streams

EPA Science Inventory

Anthropogenic land use affects aquatic landscapes. For example, landscape-level conversion to urban or agricultural land can heavily influence nutrient cycles in headwater streams via increased nutrient loading and altered hydrologic patterns. Recent studies in headwater streams ...

Hormone, metabolic peptide, and nutrient levels in the earliest phases of rheumatoid arthritis-contribution of free fatty acids to an increased cardiovascular risk during very early disease.

PubMed

Tang, Man Wai; Koopman, Frieda A; Visscher, Jan P M; de Hair, Maria J; Gerlag, Danielle M; Tak, Paul Peter

2017-02-01

Rheumatoid arthritis (RA) is a chronic autoimmune disease associated with changes in several hormones and metabolic peptides. Crosstalk between these factors and the immune system may be important for homeostasis during inflammation. Here, we studied the levels of hormones, metabolic peptides, and nutrients in individuals at risk for developing RA (at risk). In total, 18 hormones, metabolic peptides, and nutrients were measured in fasting serum samples from 45 autoantibody-positive individuals at risk, 22 RA patients, and 16 healthy subjects. Triglyceride (TG) levels were also measured in an independent validation cohort of 32 individuals at risk, 20 early arthritis patients, and 20 healthy controls. We found an elevated TG level in individuals at risk and significantly higher TG levels in RA patients compared to healthy controls. These results were confirmed in the validation cohort. Similarly, free fatty acid (FFA) levels showed an increase in individuals at risk and were significantly higher in RA patients compared to healthy controls. In RA patients, FFA levels were positively correlated with disease activity. Pancreatic polypeptide (PP) and norepinephrine levels were highly significantly increased in individuals at risk and RA patients compared to healthy controls. TG and FFA levels are increased in RA patients and positively correlated with disease activity parameters. The results presented here suggest a role for FFAs in the pathogenesis of RA. Furthermore, PP and norepinephrine may be a biomarker that could assist in the identification of individuals at risk.

Hot moments in spawning aggregations: implications for ecosystem-scale nutrient cycling

NASA Astrophysics Data System (ADS)

Archer, Stephanie K.; Allgeier, Jacob E.; Semmens, Brice X.; Heppell, Scott A.; Pattengill-Semmens, Christy V.; Rosemond, Amy D.; Bush, Phillippe G.; McCoy, Croy M.; Johnson, Bradley C.; Layman, Craig A.

2015-03-01

Biogeochemical hot moments occur when a temporary increase in availability of one or more limiting reactants results in elevated rates of biogeochemical reactions. Many marine fish form transient spawning aggregations, temporarily increasing their local abundance and thus nutrients supplied via excretion at the aggregation site. In this way, nutrients released by aggregating fish could create a biogeochemical hot moment. Using a combination of empirical and modeling approaches, we estimate nitrogen and phosphorus supplied by aggregating Nassau grouper ( Epinephelus striatus). Data suggest aggregating grouper supply up to an order-of-magnitude more nitrogen and phosphorus than daily consumer-derived nutrient supply on coral reefs without aggregating fish. Comparing current and historic aggregation-level excretion estimates shows that overfishing reduced nutrients supplied by aggregating fish by up to 87 %. Our study illustrates a previously unrecognized ecosystem viewpoint regarding fish spawning aggregations and provides an additional perspective on the repercussions of their overexploitation.

Effects of naturally mycotoxin-contaminated corn on nutrient and energy utilization of ducks fed diets with or without Calibrin-A.

PubMed

Yang, Z B; Wan, X L; Yang, W R; Jiang, S Z; Zhang, G G; Johnston, S L; Chi, F

2014-09-01

One hundred sixty-two 21-d-old ducks were randomly allotted to 6 treatments with 3 levels of mycotoxin-contaminated corn (0, 50, and 100% M) and 2 levels of Calibrin-A (CA, a clay mycotoxin adsorbent, 0 and 0.1%) to evaluate the effects of increasing levels of mycotoxin-contaminated corn on nutrient utilization in ducks fed diets with or without CA. Endogenous losses were obtained from another 27 ducks. Excreta samples were collected to determine DM, OM, CP, amino acids, and gross energy. Gross energy was analyzed for computation of AME and TME. The apparent digestibility (AD) and true digestibility (TD) of the nutrients in all treatments with and without CA had common (P > 0.05) intercepts and slopes except Pro (P < 0.05). The AME, TME, AD, and TD of DM, OM, Phe, and Gly were linearly (P < 0.05) decreased as the concentration of contaminated corn in the diet increased. Ducks fed the 100% M diet supplemented with 0.1% CA increased AD and TD of Gly compared with the 100% M diet, and ducks fed 50 and 100% M diet supplemented with 0.1% CA increased AD and TD of Pro compared with 50% M and 100% M diet, respectively. In the present study, ducks fed mycotoxin-contaminated corn decreased nutrient digestibility in dose-dependent manner, and 0.1% CA supplementation improved AD and TD of Gly and Pro. © 2014 Poultry Science Association Inc.

County-level estimates of nutrient inputs to the landsurface of the conterminous United States, 1982-2001

USGS Publications Warehouse

Ruddy, Barbara C.; Lorenz, David L.; Mueller, David K.

2006-01-01

Nutrient input data for fertilizer use, livestock manure, and atmospheric deposition from various sources were estimated and allocated to counties in the conterminous United States for the years 1982 through 2001. These nationally consistent nutrient input data are needed by the National Water-Quality Assessment Program for investigations of stream- and ground-water quality. For nitrogen, the largest source was farm fertilizer; for phosphorus, the largest sources were farm fertilizer and livestock manure. Nutrient inputs from fertilizer use in nonfarm areas, while locally important, were an order of magnitude smaller than inputs from other sources. Nutrient inputs from all sources increased between 1987 and 1997, but the relative proportions of nutrients from each source were constant. Farm-fertilizer inputs were highest in the upper Midwest, along eastern coastal areas, and in irrigated areas of the West. Nonfarm-fertilizer use was similar in major metropolitan areas throughout the Nation, but was more extensive in the more populated Eastern and Central States and in California. Areas of greater manure inputs were located throughout the South-central and Southeastern States and in scattered areas of the West. Nitrogen deposition from the atmosphere generally increased from west to east and is related to the location of major sources and the effects of precipitation and prevailing winds. These nutrient-loading data at the county level are expected to be the fundamental basis for national and regional assessments of water quality for the National Water-Quality Assessment Program and other large-scale programs.

Effects of Storm Events on Bacteria and Nutrients in the Bayou Chico Watershed

NASA Astrophysics Data System (ADS)

Hobbs, S. E.; Truong, S.

2017-12-01

Levels of Escherichia coli and abiotic nutrients often increase in response to storm events due to urban runoff. The urban setting, aging septic systems, and ample pet waste (predominant sources of bacterial and nutrient contamination) that surround Bayou Chico, provide abundant possibilities for contamination. E. coli is a gram-negative, rod shaped bacteria commonly found in the intestines of animals; while some strains are harmless, others produce dangerous toxins that can cause side effects and sometimes death. Along with E. coli, inorganic nutrient concentrations (orthophosphate, nitrate/nitrite, and ammonium) are key indicators of water quality. Dissolved nutrients promote the growth of primary producers and excessive amounts lead to algal blooms, often reducing biodiversity. Four sites were sampled weekly in June and July 2017; during which, June had the highest rainfall in comparison to the past three years; these four sites represented three different sub-watersheds of the Bayou Chico Watershed, with differing land-use at each site. Historical nutrient and bacterial data from the Bream Fishermen Association was also compared and examined to determine long term trends and obtain a more in-depth understanding of the dynamics of water quality in th urban setting. E. coli levels were universally high (ranging from 98 to 12,997 MPN/100mL) for all sites and did not show observable correlations to rainfall; possibly influenced by the systemic and anomalous heavy precipitation during most of the summer study period. Nitrate was detected at levels between 2.5 and 154.0 µM, while ammonium levels ranged from 0 to 16.1 µM. Three of four stations showed extremely elevated dissolved inorganic nitrogen and ammonium while one station showed low levels of these nutrients. Correlations between these nutrient loads and rainfall, support the hypothesis that runoff into tributary creeks contributes significant inorganic nutrient loads to the Bayou Chico urban estuary.

Nutrient composition, functional, and pasting properties of unripe cooking banana, pigeon pea, and sweetpotato flour blends.

PubMed

Ohizua, Ehimen R; Adeola, Abiodun A; Idowu, Micheal A; Sobukola, Olajide P; Afolabi, T Adeniyi; Ishola, Raphael O; Ayansina, Simeon O; Oyekale, Tolulope O; Falomo, Ayorinde

2017-05-01

This study investigated some quality attributes of unripe cooking banana (UBF), pigeon pea (PPF), and sweetpotato (SPF) flour blends. Simplex centroid mixture design was used to obtain 17 blends from the flours. The nutrient composition, color, and functional properties of the blends were evaluated using standard methods. Data were subjected to analysis of variance and treatment means were compared using Duncan's multiple range test at 5% probability level. There were significant ( p  < .05) differences in the nutrient composition, and functional and pasting properties of the blends. The crude protein, crude fiber, ash, foaming capacity, emulsion capacity, and least gelation capacity of the blends increased as the PPF level increased. The blends had Na/K ratio of <1.0. The dispersibility, bulk density, water, and oil absorption capacities of the blends increased as SPF and UBF increased. The peak, setback, and final viscosities increased as UBF and SPF inclusion increased,whereas pasting temperature and time increased as the PPF level increased. The L*, a*, and b* values of the flour blends which were significantly ( p  < .05) different ranged from 79.58 to 102.71, -0.15 to 2.79, and 13.82 to 23.69, respectively. Cooking banana-pigeon pea-sweetpotato flour blends are desirable for alleviating malnutrition in Nigeria and developing new food formulations.

Calcium Deficiency of Dark-grown Seedlings of Phaseolus vulgaris L.

PubMed

Helms, K

1971-06-01

Hypocotyl collapse in dark-grown seedlings of Phaseolus vulgaris cv. Pinto was due to calcium deficiency. There was no evidence of an associated pathogen. The number of seedlings with hypocotyl collapse decreased and the mean hypocotyl length increased when increasing levels of calcium (0-100 micrograms per gram) were supplied in an external nutrient solution to seedlings grown under sterile conditions.When seedlings were supplied with a complete nutrient solution, containing calcium at 100 micrograms per gram, but minus potassium, magnesium, sulfur, nitrogen, or phosphorus, occasional plants developed hypocotyl collapse symptoms; however, the lengths of hypocotyls varied little from those of controls grown in complete nutrient. When the calcium level in the deficient nutrient solutions was raised to 200 micrograms per gram, the number of plants with hypocotyl collapse was reduced markedly.With complete nutrient solution minus calcium, seedlings developed symptoms of calcium deficiency irrespective of seed size, i.e., irrespective of whether or not the seed contained a total calcium content that was low or relatively high.An increase in hypocotyl length in response to an external supply of calcium was obtained with five cultivars of Phaseolus vulgaris L. and with one of Soja max Piper. A similar response to calcium was obtained for epicotyl growth of a cultivar of Vicia faba L., but not for a cultivar of Pisum sativum L.

Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone.

PubMed

Miller, J J; Bremer, E; Curtis, T

2016-07-01

Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Additional BCAA-enriched nutrient mixture improves the nutritional condition in cirrhotic patients with hypoalbuminemia despite treatment with regular BCAA granules: A pilot study.

PubMed

Fukui, Aiko; Kawabe, Naoto; Hashimoto, Senju; Murao, Michihito; Nakano, Takuji; Shimazaki, Hiroaki; Kan, Toshiki; Nakaoka, Kazunori; Ohki, Masashi; Takagawa, Yuka; Kamei, Hiroyuki; Yoshioka, Kentaro

2015-07-01

To elucidate the effect of adding branched-chain amino acid (BCAA)-enriched nutrient mixtures in cirrhotic patients with hypoalbuminemia despite the use of BCAA granules. A BCAA-enriched nutrient mixture containing 5.6 g of BCAA and 210 kcal was additionally administered in 40 cirrhotic patients with hypoalbuminemia despite their treatment with BCAA granules containing 12 g of BCAA. Laboratory data were assessed at 6 months before beginning additional therapy, at baseline, and at 6 months after baseline. Serum albumin levels significantly decreased from 6 months before baseline (3.14±0.47 g/dL) to baseline (2.83±0.46 g/dL), despite the treatment with BCAA granules (p<0.001), and tended to increase from baseline to 6 months after baseline (2.95±0.42 g/dL) (p=0.084). In the subset of 23 patients without hepatocellular carcinoma treatments, upper gastrointestinal tract bleeding, or albumin infusion, serum albumin levels significantly increased from baseline (2.93±0.38 g/dL) to 6 months after baseline (3.15±0.34 g/dL) (p=0.014). Additional therapy with BCAA-enriched nutrient mixtures increased serum albumin levels of the cirrhotic patients with hypoalbuminemia despite the treatment with BCAA granules and without hepatocellular carcinoma treatment, upper gastrointestinal tract bleeding, or albumin infusion.

Recovery of three arctic stream reaches from experimental nutrient enrichment

USGS Publications Warehouse

Benstead, J.P.; Green, A.C.; Deegan, Linda A.; Peterson, B.J.; Slavik, K.; Bowden, W.B.; Hershey, A.E.

2007-01-01

1. Nutrient enrichment and resulting eutrophication is a widespread anthropogenic influence on freshwater ecosystems, but recovery from nutrient enrichment is poorly understood, especially in stream environments. We examined multi-year patterns in community recovery from experimental low-concentration nutrient enrichment (N + P or P only) in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (U.S.A.). 2. Rates of recovery varied among community components and depended on duration of enrichment (2-13 consecutive growing seasons). Biomass of epilithic algae returned to reference levels rapidly (within 2 years), regardless of nutrients added or enrichment duration. Aquatic bryophyte cover, which increased greatly in the Kuparuk River only after long-term enrichment (8 years), took 8 years of recovery to approach reference levels, after storms had scoured most remnant moss in the recovering reach. 3. Multi-year persistence of bryophytes in the Kuparuk River appeared to prevent recovery of insect populations that had either been positively (e.g. the mayfly Ephemerella, most chironomid midge taxa) or negatively (e.g. the tube-building chironomid Orthocladius rivulorum) affected by this shift in dominant primary producer. These lags in recovery (of >3 years) were probably driven by the persistent effect of bryophytes on physical benthic habitat. 4. Summer growth rates of Arctic grayling (both adults and young-of-year) in Oksrukuyik Creek (fertilised for 6 years with no bryophyte colonisation), which were consistently increased by nutrient addition, returned to reference rates within 1-2 years. 5. Rates of recovery of these virtually pristine Arctic stream ecosystems from low-level nutrient enrichment appeared to be controlled largely by duration of enrichment, mediated through physical habitat shifts caused by eventual bryophyte colonisation, and subsequent physical disturbance that removed bryophytes. Nutrient enrichment of oligotrophic Arctic stream ecosystems caused by climate change or local anthropogenic activity may have dramatic and persistent consequences if it results in the colonisation of long-lived primary producers that alter physical habitat. ?? 2007 The Authors.

A quantitative assessment of the contributions of climatic indicators to changes in nutrients and oxygen levels in a shallow reservoir in China

NASA Astrophysics Data System (ADS)

Zhang, Chen; Zhang, Wenna; Liu, Hanan; Gao, Xueping; Huang, Yixuan

2017-06-01

Climate change has an indirect effect on water quality in freshwater ecosystems, but it is difficult to assess the contribution of climate change to the complex system. This study explored to what extent climatic indicators (air temperature, wind speed, and rainfall) influence nutrients and oxygen levels in a shallow reservoir, Yuqiao Reservoir, China. The study comprises three parts—describing the temporal trends of climatic indicators and water quality parameters during the period 1992-2011, analyzing the potential impacts of climate on water quality, and finally developing a quantitative assessment to evaluate how climatic factors govern nutrient levels in the reservoir. Our analyses showed that the reservoir experienced substantial cold periods (1992-2001) followed by a warm period (2002-2011). The results showed that increasing air temperature in spring, autumn, and winter and increasing annual wind speed decrease total phosphorus (TP) concentration in the reservoir in spring, summer, and winter. According to the quantitative assessment, the increase in air temperature in spring and winter had a larger contribution to the decrease in TP concentration (47.2 and 64.1%), compared with the influence from decreased wind speed and rainfall. The field data suggest that nutrients decline due to enhanced uptake by macrophytes in years when spring was warmer and the macrophytes started to grow earlier in the season. The increasing wind speed and air temperature in spring also significantly contribute to the increase in dissolved oxygen concentration. This study helps managers to foresee how potential future climate change might influence water quality in similar lake ecosystems.

Contribution of Dietary Supplements to Nutritional Adequacy by Socioeconomic Subgroups in Adults of the United States.

PubMed

Blumberg, Jeffrey B; Frei, Balz; Fulgoni, Victor L; Weaver, Connie M; Zeisel, Steven H

2017-12-22

Many Americans have inadequate intakes of several nutrients, and the Dietary Guidelines for Americans 2015-2020 identified vitamins A, C, D, and E, in addition to calcium, magnesium, iron, potassium, choline, and fiber as "underconsumed nutrients". Based on nationally representative data on 10,698 adults from National Health and Nutrition Examination Surveys (NHANES), 2009-2012, assessments were made of socioeconomic differences, based on the Poverty Income Ratio (PIR), in terms of the association of dietary supplement use on nutrient intake and nutrient inadequacies. Compared to food alone, the use of any dietary supplement plus food was associated with significantly ( p < 0.01) higher intakes of 15-16 of 19 nutrients examined in all socioeconomic groups; and significantly reduced rates of inadequacy for 10/17 nutrients in the subgroup PIR > 1.85 (not poor), but only 4-5/17 nutrients (calcium and vitamins A, C, D, E) for the poor and nearly poor subgroups (PIR < 1.35 and PIR 1.35 to ≤1.85, respectively). An increased prevalence of intakes above the Tolerable Upper Intake Level (UL) was seen for 3-9/13 nutrients, but all were less than 5% in the PIR subgroups. In conclusion, dietary supplement use was associated with an increased micronutrient intake, decreased inadequacies, and a slight increase in the prevalence of intakes above the UL, with greater benefits seen in the PIR > 1.85 subgroup.

Effects of preparation on nutrient and environmental contaminant levels in Arctic beluga whale (Delphinapterus leucas) traditional foods.

PubMed

Binnington, Matthew J; Lei, Ying D; Pokiak, Lucky; Pokiak, James; Ostertag, Sonja K; Loseto, Lisa L; Chan, Hing M; Yeung, Leo W Y; Huang, Haiyong; Wania, Frank

2017-08-16

For Canadian Arctic indigenous populations, marine mammal (MM) traditional foods (TFs) represent sources of both important nutrients and hazardous environmental contaminants. Food preparation is known to impact the nutrient and environmental contaminant content of processed items, yet the impacts of preparation on indigenous Arctic MM TFs remain poorly characterized. In order to determine how the various processes involved in preparing beluga blubber TFs affect their levels of nutrients and environmental contaminants, we collected blubber samples from 2 male beluga whales, aged 24 and 37 years, captured during the 2014 summer hunting season in Tuktoyaktuk, Northwest Territories, and processed them according to local TF preparation methods. We measured the levels of select nutrients [selenium (Se), polyunsaturated fatty acids (PUFAs)] and contaminants [organochlorine pesticides, perfluoroalkyl and polyfluoroalkyl substances (PFASs), polybrominated diphenyl ethers, polychlorinated biphenyls, polycyclic aromatic hydrocarbons (PAHs), mercury (Hg)] in raw and prepared (boiled, roasted, aged) beluga blubber TFs. The impacts of beluga blubber TF preparation methods on nutrient and environmental contaminant levels were inconsistent, as the majority of processes either did not appear to influence concentrations or affected the two belugas differently. However, roasting and ageing beluga blubber consistently impacted certain compounds: roasting blubber increased concentrations of hydrophilic substances (Se and certain PFASs) through solvent depletion and deposited PAHs from cookfire smoke. The solid-liquid phase separation involved in ageing blubber depleted hydrophilic elements (Se, Hg) and some ionogenic PFASs from the lipid-rich liquid oil phase, while PUFA levels appeared to increase, and hydrophobic persistent organic pollutants were retained. Ageing blubber adjacent to in-use smokehouses also resulted in considerable PAH deposition to processed samples. Our findings demonstrated that contaminant concentration differences were greater between the two sets of whale samples, based on age differences, than they were within each set of whale samples, due to variable preparation methods. When considering means to minimize human contaminant exposure while maximizing nutrient intake, consumption of aged liquid from younger male whales would be preferred, based on possible PUFA enhancement and selective depletion of hydrophilic environmental contaminants in this food item.

Resiliency of the Chesapeake Bay to Pollution Levels Following Storms and Based on Land-Use

NASA Astrophysics Data System (ADS)

Hasan, M.; Pavelsky, T.

2015-12-01

As pollution levels, transformations in land use, and ecological loss continue to increase in the Chesapeake Bay, questions arise as to whether this estuary, the largest in North America, will experience a change in the duration and levels of storm-related sediment and nutrient spikes. We use a combination of satellite data and previously-collected field measurements to study this question. We compare same-day and same-pixel NASA MODIS satellite data to in situ observations of sediment and nutrient concentrations over 20 years, and found that for at least 6 tributaries, the r2 value for a linear regression between the satellite reflectance and fieldwork measures of nitrogen, phosphorus, or suspended sediment concentrations exceeded 0.7, while for at least 12 tributaries, the r2 value exceeded 0.5. We took advantage of this relationship to estimate sediment and nutrient concentrations in the Chesapeake following major storm events, even in the absence of continuous in situ data. We studied sediment/nutrient levels daily following the storm, for every date on which a cloud-free MODIS image was available, for a month. The storms included 2003's Hurricane Isabel, 2011's Hurricane Irene, and 2012's Superstorm Sandy. The tributaries we focused on were the York and Piankatank Rivers of southern Virginia (heavily forested), the Potomac River (heavily urban), and the Nanticoke River of the Eastern Shore (heavily farmed). Results show that in the Potomac River, which over the last 15 years has experience a signifiant increase in urbanization, sediments and nutrients persist for longer periods and at higher levels compared to less urbanized rivers.

Nutrient dynamics in tropical rivers, lagoons, and coastal ecosystems of eastern Hainan Island, South China Sea

NASA Astrophysics Data System (ADS)

Li, R. H.; Liu, S. M.; Li, Y. W.; Zhang, G. L.; Ren, J. L.; Zhang, J.

2014-01-01

Nutrient dynamics based on field observations made along the eastern Hainan Island during the period 2006-2009 were investigated to understand nutrient biogeochemical processes, and to provide an overview of human perturbations of coastal ecosystems in this tropical region. The rivers showed seasonal variations in nutrient concentrations, with enrichment of dissolved inorganic nitrogen and dissolved silicate, and depletion of PO43-. High riverine concentrations of nitrate mainly originated from agricultural fertilizer inputs. The DIN : PO43- ratios ranged from 37 to 1063, suggesting preferential depletion of PO43- relative to nitrogen in rivers. Chemical weathering in the drainage area might explain the high levels of dissolved silicate. Aquaculture ponds contained high concentrations of NH4+ and dissolved organic nitrogen. The particulate phosphorus concentrations in the study area were lower than those reported for estuaries worldwide. The particulate silicate levels in rivers and lagoons were lower than the global average level. Nutrient biogeochemistry in coastal areas was affected by human activities (e.g., aquaculture, agriculture), and by natural phenomena including typhoons. The nutrient concentrations in coastal waters were low because of dispersion of land-derived nutrients in the sea. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes are magnified by estuarine processes (e.g., regeneration, desorption) in estuaries and Laoyehai Lagoon, but not in Xiaohai Lagoon. Riverine and groundwater inputs were the major sources of nutrients to Xiaohai and Laoyehai lagoons, respectively, and riverine inputs and aquaculture effluents were the major sources for the eastern coast of Hainan Island. Nutrient inputs to the coastal ecosystem increased with typhoon-induced runoff of rainwater, elucidating the important influence of typhoons on small tropical rivers.

Nutrients Turned into Toxins: Microbiota Modulation of Nutrient Properties in Chronic Kidney Disease

PubMed Central

Fernandez-Prado, Raul; Esteras, Raquel; Perez-Gomez, Maria Vanessa; Gracia-Iguacel, Carolina; Gonzalez-Parra, Emilio; Sanz, Ana B.; Ortiz, Alberto; Sanchez-Niño, Maria Dolores

2017-01-01

In chronic kidney disease (CKD), accumulation of uremic toxins is associated with an increased risk of death. Some uremic toxins are ingested with the diet, such as phosphate and star fruit-derived caramboxin. Others result from nutrient processing by gut microbiota, yielding precursors of uremic toxins or uremic toxins themselves. These nutrients include l-carnitine, choline/phosphatidylcholine, tryptophan and tyrosine, which are also sold over-the-counter as nutritional supplements. Physicians and patients alike should be aware that, in CKD patients, the use of these supplements may lead to potentially toxic effects. Unfortunately, most patients with CKD are not aware of their condition. Some of the dietary components may modify the gut microbiota, increasing the number of bacteria that process them to yield uremic toxins, such as trimethylamine N-Oxide (TMAO), p-cresyl sulfate, indoxyl sulfate and indole-3 acetic acid. Circulating levels of nutrient-derived uremic toxins are associated to increased risk of death and cardiovascular disease and there is evidence that this association may be causal. Future developments may include maneuvers to modify gut processing or absorption of these nutrients or derivatives to improve CKD patient outcomes. PMID:28498348

Nutrients Turned into Toxins: Microbiota Modulation of Nutrient Properties in Chronic Kidney Disease.

PubMed

Fernandez-Prado, Raul; Esteras, Raquel; Perez-Gomez, Maria Vanessa; Gracia-Iguacel, Carolina; Gonzalez-Parra, Emilio; Sanz, Ana B; Ortiz, Alberto; Sanchez-Niño, Maria Dolores

2017-05-12

In chronic kidney disease (CKD), accumulation of uremic toxins is associated with an increased risk of death. Some uremic toxins are ingested with the diet, such as phosphate and star fruit-derived caramboxin. Others result from nutrient processing by gut microbiota, yielding precursors of uremic toxins or uremic toxins themselves. These nutrients include l-carnitine, choline/phosphatidylcholine, tryptophan and tyrosine, which are also sold over-the-counter as nutritional supplements. Physicians and patients alike should be aware that, in CKD patients, the use of these supplements may lead to potentially toxic effects. Unfortunately, most patients with CKD are not aware of their condition. Some of the dietary components may modify the gut microbiota, increasing the number of bacteria that process them to yield uremic toxins, such as trimethylamine N-Oxide (TMAO), p-cresyl sulfate, indoxyl sulfate and indole-3 acetic acid. Circulating levels of nutrient-derived uremic toxins are associated to increased risk of death and cardiovascular disease and there is evidence that this association may be causal. Future developments may include maneuvers to modify gut processing or absorption of these nutrients or derivatives to improve CKD patient outcomes.

Effects of Salinity and Nutrient Addition on Mangrove Excoecaria agallocha

PubMed Central

Chen, Yaping; Ye, Yong

2014-01-01

Effects of salinity on seed germination and growth of young (1 month old) and old (2-year old) seedlings of Excoecaria agallocha were investigated. Combined effects of salinity and nutrient level were also examined on old seedlings. Seed germination was best at 0 and 5 psu salinity. 15 psu salinity significantly delayed root initiation and decreased final establishment rate. All seeds failed to establish at 25 psu salinity. Young seedlings performed best at 0 and 5 psu, but growth was stunned at 15 psu, and all seedlings died within 90 days at 25 psu. Old seedlings grew best at salinities below 5 psu and they survived the whole cultivation at 25 psu. This indicated that E. agallocha increased salt tolerance over time. Gas exchange was significantly compromised by salinities above 15 psu but evidently promoted by high nutrient. Proline accumulated considerably at high nutrient, and its contents increased from 0 to 15 psu but decreased at 25 psu salinity. Lipid peroxidation was aggravated by increasing salinity beyond 15 psu but markedly alleviated by nutrient addition. These responses indicated that E. agallocha was intolerant to high salinity but it can be greatly enhanced by nutrient addition. PMID:24691495

Sensations induced by medium and long chain triglycerides: role of gastric tone and hormones

PubMed Central

Barbera, R; Peracchi, M; Brighenti, F; Cesana, B; Bianchi, P; Basilisco, G

2000-01-01

BACKGROUND—The relative roles of gastric relaxation and the neuroendocrine signals released by the small intestine in the perception of nutrient induced sensations are controversial. The different effects of long chain (LCT) and medium chain (MCT) triglyceride ingestion on perception, gastric relaxation, and hormonal release may help to elucidate the mechanisms underlying nutrient induced sensations.
AIMS—To compare the effects of intraduodenal LCT and MCT infusions on perception, gastric tone, and plasma gut hormone levels in healthy subjects.
SUBJECTS—Nine fasting healthy volunteers.
METHODS—The subjects received duodenal infusions of saline followed by LCTs and MCTs in a randomised order on two different days. The sensations were rated on a visual analogue scale. Gastric tone was measured using a barostat, and plasma gut hormone levels by radioimmunoassay.
RESULTS—LCT infusion increased satiation scores, reduced gastric tone, and increased the levels of plasma cholecystokinin, gastric inhibitory polypeptide, neurotensin, and pancreatic polypeptide. MCT infusion reduced gastric tone but did not significantly affect perception or plasma gut hormone levels. LCTs produced greater gastric relaxation than MCTs.
CONCLUSIONS—The satiation induced by intraduodenal LCT infusion seems to involve changes in gastric tone and plasma gut hormone levels. The gastric relaxation induced by MCT infusion, together with the absence of any significant change in satiation scores and plasma hormone levels, suggests that, at least up to a certain level, gastric relaxation is not sufficient to induce satiation and that nutrient induced gastric relaxation may occur through cholecystokinin independent mechanisms.


Keywords: gastric tone; triglyceride; hormones; satiation; cholecystokinin; nutrients PMID:10601051

1H-NMR-Based Metabolic Profiling of Maternal and Umbilical Cord Blood Indicates Altered Materno-Foetal Nutrient Exchange in Preterm Infants

PubMed Central

Küster, Alice; Guignard, Nadia; Alexandre–Gouabau, Marie-Cécile; Darmaun, Dominique; Robins, Richard J.

2012-01-01

Background Adequate foetal growth is primarily determined by nutrient availability, which is dependent on placental nutrient transport and foetal metabolism. We have used 1H nuclear magnetic resonance (NMR) spectroscopy to probe the metabolic adaptations associated with premature birth. Methodology The metabolic profile in 1H NMR spectra of plasma taken immediately after birth from umbilical vein, umbilical artery and maternal blood were recorded for mothers delivering very-low-birth-weight (VLBW) or normo-ponderal full-term (FT) neonates. Principal Findings Clear distinctions between maternal and cord plasma of all samples were observed by principal component analysis (PCA). Levels of amino acids, glucose, and albumin-lysyl in cord plasma exceeded those in maternal plasma, whereas lipoproteins (notably low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) and lipid levels were lower in cord plasma from both VLBW and FT neonates. The metabolic signature of mothers delivering VLBW infants included decreased levels of acetate and increased levels of lipids, pyruvate, glutamine, valine and threonine. Decreased levels of lipoproteins glucose, pyruvate and albumin-lysyl and increased levels of glutamine were characteristic of cord blood (both arterial and venous) from VLBW infants, along with a decrease in levels of several amino acids in arterial cord blood. Conclusion These results show that, because of its characteristics and simple non-invasive mode of collection, cord plasma is particularly suited for metabolomic analysis even in VLBW infants and provides new insights into the materno-foetal nutrient exchange in preterm infants. PMID:22291897

Increased resource use efficiency amplifies positive response of aquatic primary production to experimental warming.

PubMed

Hood, James M; Benstead, Jonathan P; Cross, Wyatt F; Huryn, Alexander D; Johnson, Philip W; Gíslason, Gísli M; Junker, James R; Nelson, Daniel; Ólafsson, Jón S; Tran, Chau

2018-03-01

Climate warming is affecting the structure and function of river ecosystems, including their role in transforming and transporting carbon (C), nitrogen (N), and phosphorus (P). Predicting how river ecosystems respond to warming has been hindered by a dearth of information about how otherwise well-studied physiological responses to temperature scale from organismal to ecosystem levels. We conducted an ecosystem-level temperature manipulation to quantify how coupling of stream ecosystem metabolism and nutrient uptake responded to a realistic warming scenario. A ~3.3°C increase in mean water temperature altered coupling of C, N, and P fluxes in ways inconsistent with single-species laboratory experiments. Net primary production tripled during the year of experimental warming, while whole-stream N and P uptake rates did not change, resulting in 289% and 281% increases in autotrophic dissolved inorganic N and P use efficiency (UE), respectively. Increased ecosystem production was a product of unexpectedly large increases in mass-specific net primary production and autotroph biomass, supported by (i) combined increases in resource availability (via N mineralization and N 2 fixation) and (ii) elevated resource use efficiency, the latter associated with changes in community structure. These large changes in C and nutrient cycling could not have been predicted from the physiological effects of temperature alone. Our experiment provides clear ecosystem-level evidence that warming can shift the balance between C and nutrient cycling in rivers, demonstrating that warming will alter the important role of in-stream processes in C, N, and P transformations. Moreover, our results reveal a key role for nutrient supply and use efficiency in mediating responses of primary producers to climate warming. © 2017 John Wiley & Sons Ltd.

Economic development influences on sediment-bound nitrogen and phosphorus accumulation of lakes in China.

PubMed

Ni, Zhaokui; Wang, Shengrui

2015-12-01

China has been confronted with serious water quality deterioration concurrent with rapid socioeconomic progress during the past 40 years. Consequently, knowledge about economic growth and lake water quality dynamics is important to understand eutrophication processes. Objectives were to (i) reconstruct historical nutrient accumulation and the basin economic progress on burial flux (BF); (ii) determine forms and structures of nitrogen (N) and phosphorus (P) in sediment and water using six cores in three of the most severely eutrophic lake areas in China (i.e., Eastern Plain, Yunnan-Guizhou Plain, and Inner Mongolia-Xinjiang regions). Results suggest that BFs of total nitrogen (TN) continued to increase in sediment, whereas total phosphorus (TP) levels were consistent or only slightly increased, except in highly polluted lakes during the past decades. Similar results were observed for concentrations of nutrients in water (i.e., increased N/P). This historical distribution pattern was correlated to long-term fertilization practices of farmers in the watershed (N fertilization exceeds that of P) and was contingent upon pollution control policies (e.g., emphasized P whereas N was ignored). Vertical profiles of BFs indicated that lake nutrient accumulation included three stages in China. Nutrient accumulation started in the 1980s, accelerated from the 1990s, and then declined after 2000. Before the 1980s, nutrients were relatively low and stable, with nutrient inputs being controlled by natural processes. Thereafter, N- and P-bound sediments dramatically increased due to the increasing influence of anthropogenic processes. Nutrients were primarily derived from industries and domestic sewage. After 2000, BFs of nutrients were steady and even decreased, owing to implementation of watershed load reduction policies. The decreasing NaOH-extracted P (Fe/Al-P) and increasing organic phosphorus (OP) indicated that the source of exogenous pollution underwent a shift. Inputs of nutrients were predominantly from agricultural and domestic sewage, whereas industrial pollution has been gradually controlled in most of the watersheds. Historical nutrient dynamics suggest that the economy of China is growing at the expense of its aquatic ecological environments. Therefore, more attention to nutrient export to groundwater resulting from economic development is important for further aquatic ecosystem deterioration and eutrophication in China.

Responses of plant nutrient resorption to phosphorus addition in freshwater marsh of Northeast China

PubMed Central

Mao, Rong; Zeng, De-Hui; Zhang, Xin-Hou; Song, Chang-Chun

2015-01-01

Anthropogenic activities have increased phosphorus (P) inputs to most aquatic and terrestrial ecosystems. However, the relationship between plant nutrient resorption and P availability is still unclear, and much less is known about the underlying mechanisms. Here, we used a multi-level P addition experiment (0, 1.2, 4.8, and 9.6 g P m−2 year−1) to assess the effect of P enrichment on nutrient resorption at plant organ, species, and community levels in a freshwater marsh of Northeast China. The response of nutrient resorption to P addition generally did not vary with addition rates. Moreover, nutrient resorption exhibited similar responses to P addition across the three hierarchical levels. Specifically, P addition decreased nitrogen (N) resorption proficiency, P resorption efficiency and proficiency, but did not impact N resorption efficiency. In addition, P resorption efficiency and proficiency were linearly related to the ratio of inorganic P to organic P and organic P fraction in mature plant organs, respectively. Our findings suggest that the allocation pattern of plant P between inorganic and organic P fractions is an underlying mechanism controlling P resorption processes, and that P enrichment could strongly influence plant-mediated biogeochemical cycles through altered nutrient resorption in the freshwater wetlands of Northeast China. PMID:25631373

Selection of nutrients for prevention or amelioration of lead-induced learning and memory impairment in rats.

PubMed

Fan, Guangqin; Feng, Chang; Li, Yu; Wang, Chunhong; Yan, Ji; Li, Wei; Feng, Jiangao; Shi, Xianglin; Bi, Yongyi

2009-06-01

We carried out animal experiments based on the orthogonal design L(8)(2(7)) setting seven factors with two different levels of each and 10 groups of rats. The nutrients tested were tyrosine, glycine, methionine, taurine, ascorbic acid, thiamine and zinc. The objective of this study was to explore the optimal combinations of nutrients for prevention or amelioration of lead-induced learning and memory impairment. Rats were supplemented with nutrients by gavage once a day in two experiments: one was simultaneous nutrient supplementation with lead acetate administration (800 mg l(-1)) for 8 weeks (prophylactic supplementation) and the other was nutrient supplementation for 4 weeks after the cessation of 4 weeks of lead administration (remedial supplementation). Morris water maze was initiated at ninth week. Rats were terminated for assays of levels of Pb in blood, activities of superoxide dismutase (SOD) and nitric oxide synthase (NOS) in hippocampus, levels of nitric oxide (NO) in hippocampus and expressions of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and cyclic adenosine monophosphate (cAMP) response element-binding protein messenger RNA in hippocampus. Results showed that in prophylactic supplementation, methionine, taurine, zinc, ascorbic acid and glycine were the effective preventive factors for decreasing prolonged escape latency, increasing SOD and NOS activities and NO levels in the hippocampus, respectively. On the other hand, in remedial supplementation, taurine was the effective factor for reversing Pb-induced decrease in activities of SOD, NOS and levels of NO. In conclusion, the optimum combinations of nutrients appear to be methionine, taurine, zinc, ascorbic acid and glycine for the prevention of learning and memory impairment, while taurine and thiamine appear to be the effective factors for reversing Pb neurotoxicity.

Sodium relations in desert plants. V. Cation balance when grown in solution culture and in the field in three species of Lycium from the northern Mojave desert

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashcroft, R.T.; Wallace, A.

1976-07-01

Three species of Lycium (wolfberry or desert thorn) are indicators of saline conditions of the soils of the northern Mojave Desert on which they grow and range from a halophyte (Lycium shockleyi Gray) to a partial halophyte (Lycium pallidum Miers) to a nonhalophyte (Lycium andersonii Gray). Each species was grown in nutrient solutions with varying Na levels to determine if the differential responses to cations in the field were reproducible in the glasshouse. The differences in Na, K, and Ca contents of leaves of L. andersonii, L. pallidum, and L. shockleyi grown in nutrient solution with varying cation levels weremore » similar to those for plants grown in the field. L. shockleyi accumulated large quantities of Na in leaves when supplied irrespective of the level of Na or of K and Ca in the nutrient substrate. Root and leaf analyses indicate that L. andersonii is a poor accumulator of Na and that the other two Lycium species transport Na to shoots rather than retain it in roots. A high level of NaCl in the nutrient substrate resulted in increased total cations in all three species; in L. shockleyi the increase was the result of an increased Na, but in L. andersonii it was due to increased Ca. There was no relationship in total cation contents of the plants with total contents of N + P + Cl (me basis as ions are absorbed by plants). In whole plants collected from the field, high cation concentrations in leaves were related to differential distribution among plant parts for the three species so that leaf differences were compensated for without differences on the whole plant basis.« less

Response of nutrients, biofilm, and benthic insects to salmon carcass addition.

Treesearch

Shannon M. Claeson; Judith L. Li; Jana E. Compton; Peter A. Bisson

2006-01-01

Salmon carcass addition to streams is expected to increase stream productivity at multiple trophic levels. This study examined stream nutrient (nitrogen, phosphorus, and carbon), epilithic biofilm (ash-free dry mass and chlorophyll a), leaf-litter decomposition, and macroinvertebrate (density and biomass) responses to carcass addition in three headwater streams of...

A LANDSCAPE MODEL TO PREDICT TOTAL NITROGEN LEVELS IN SURFACE WATERS OF THE WILLAMETTE AND CENTRAL VALLEYS ECOREGION OF THE WESTERN UNITED STATES

EPA Science Inventory

Excess nutrients are a leading cause of impairment to streams, rivers, lakes and the coastal ecosystems. Excessive nutrient loadings result in increased primary productivity of plant and algal communities leading to eutrophication and other impacts to aquatic resources. Nitrogen ...

Effect of multiple stressors on eelgrass Zostera marina L. from the Pacific Northwest, USA: Manipulation of temperature and nutrients

EPA Science Inventory

Estuarine eelgrass beds in the Pacific Northwest (PNW) are being exposed to a range of natural and anthropogenic stressors and climate change. These stresses include increased temperatures, sea level rise, and high nutrient inputs, all of which may directly affect the productivi...

Iron and protein biofortification of cassava: lessons learned.

PubMed

Leyva-Guerrero, Elisa; Narayanan, Narayanan N; Ihemere, Uzoma; Sayre, Richard T

2012-04-01

Over two hundred and fifty million Africans rely on the starchy root crop cassava (Manihot esculenta) as their primary source of calories. Cassava roots, however, have the lowest protein:energy ratio of all the world's major staple crops. Furthermore, a typical cassava-based diet provides less than 10-20% of the required amounts of iron, zinc, vitamin A and vitamin E. The BioCassava Plus program employed modern biotechnologies to improve the health of Africans through development and delivery of novel cassava germplasm with increased nutrient levels. Here we describe the development of molecular strategies and their outcomes to meet minimum daily allowances for protein and iron in cassava based diets. We demonstrate that cyanogens play a central role in cassava nitrogen metabolism and that strategies employed to increase root protein levels result in reduced cyanogen levels in roots. We also demonstrate that enhancing root iron uptake has an impact on the expression of genes that regulate iron homeostasis in multiple tissues. These observations demonstrate the complex metabolic interactions involved in enhancing targeted nutrient levels in plants and identify potential new strategies for further enhancing nutrient levels in cassava. Published by Elsevier Ltd.

Nutrient Content of Brown Marmorated Stink Bug Eggs and Comparisons Between Experimental Uses

PubMed Central

Skillman, Victoria P

2017-01-01

Abstract Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), the brown marmorated stink bug (BMSB), has become a major pest. Seven experiments examined the nutrient content of their eggs in the context of female reproductive investment and use for experiments. Among 542 clusters examined, an average egg contained 23.50 ± 0.561 µg lipid, 3.17 ± 0.089 µg glycogen, and 3.08 ± 0.056 µg sugar. Mature eggs within a female’s ovary can make up 61% of her total lipid, 35% of glycogen, and 20% of sugar levels. Eggs obtained from a colony reared on a steady diet are expected to have consistent nutrient content. The age of a parental female only slightly affected the lipid level of oviposited eggs but did not affect glycogen or sugar levels. However, egg nutrient content can differ substantially by the source of the parental females; wild eggs had higher lipid but lower sugar content than colony-produced eggs. Further, the length of time that eggs are frozen influenced egg nutrient content. Freshly laid eggs had higher lipid and lower sugar levels than eggs frozen for 1 or 2 yr. Whether an egg turned grey following removal from cold storage did not affect nutrient content, nor did being frozen within 1 or 3 d of oviposition. The temperature at which eggs were left exposed did not impact egg nutrient content, but glycogen decreased and sugar increased with deployment time. This information combined with how factors affect host selection by natural enemies will help refine future experiments that use BMSB egg clusters.

Variable nutrient stoichiometry (carbon:nitrogen:phosphorus) across trophic levels determines community and ecosystem properties in an oligotrophic mangrove system.

PubMed

Scharler, U M; Ulanowicz, R E; Fogel, M L; Wooller, M J; Jacobson-Meyers, M E; Lovelock, C E; Feller, I C; Frischer, M; Lee, R; McKee, K; Romero, I C; Schmit, J P; Shearer, C

2015-11-01

Our study investigated the carbon:nitrogen:phosphorus (C:N:P) stoichiometry of mangrove island of the Mesoamerican Barrier Reef (Twin Cays, Belize). The C:N:P of abiotic and biotic components of this oligotrophic ecosystem was measured and served to build networks of nutrient flows for three distinct mangrove forest zones (tall seaward fringing forest, inland dwarf forests and a transitional zone). Between forest zones, the stoichiometry of primary producers, heterotrophs and abiotic components did not change significantly, but there was a significant difference in C:N:P, and C, N, and P biomass, between the functional groups mangrove trees, other primary producers, heterotrophs, and abiotic components. C:N:P decreased with increasing trophic level. Nutrient recycling in the food webs was highest for P, and high transfer efficiencies between trophic levels of P and N also indicated an overall shortage of these nutrients when compared to C. Heterotrophs were sometimes, but not always, limited by the same nutrient as the primary producers. Mangrove trees and the primary tree consumers were P limited, whereas the invertebrates consuming leaf litter and detritus were N limited. Most compartments were limited by P or N (not by C), and the relative depletion rate of food sources was fastest for P. P transfers thus constituted a bottleneck of nutrient transfer on Twin Cays. This is the first comprehensive ecosystem study of nutrient transfers in a mangrove ecosystem, illustrating some mechanisms (e.g. recycling rates, transfer efficiencies) which oligotrophic systems use in order to build up biomass and food webs spanning various trophic levels.

Variable nutrient stoichiometry (carbon:nitrogen:phosphorus) across trophic levels determines community and ecosystem properties in an oligotrophic mangrove system

USGS Publications Warehouse

Scharler, U.M.; Ulanowicz, Robert E.; Fogel, M.L.; Wooller, M.J.; Jacobson-Meyers, M.E.; Lovelock, C.E.; Feller, I.C.; Frischer, M.; Lee, R.; Mckee, Karen L.; Romero, I.C.; Schmit, J.P.; Shearer, C.

2015-01-01

Our study investigated the carbon:nitrogen:phosphorus (C:N:P) stoichiometry of mangrove island of the Mesoamerican Barrier Reef (Twin Cays, Belize). The C:N:P of abiotic and biotic components of this oligotrophic ecosystem was measured and served to build networks of nutrient flows for three distinct mangrove forest zones (tall seaward fringing forest, inland dwarf forests and a transitional zone). Between forest zones, the stoichiometry of primary producers, heterotrophs and abiotic components did not change significantly, but there was a significant difference in C:N:P, and C, N, and P biomass, between the functional groups mangrove trees, other primary producers, heterotrophs, and abiotic components. C:N:P decreased with increasing trophic level. Nutrient recycling in the food webs was highest for P, and high transfer efficiencies between trophic levels of P and N also indicated an overall shortage of these nutrients when compared to C. Heterotrophs were sometimes, but not always, limited by the same nutrient as the primary producers. Mangrove trees and the primary tree consumers were P limited, whereas the invertebrates consuming leaf litter and detritus were N limited. Most compartments were limited by P or N (not by C), and the relative depletion rate of food sources was fastest for P. P transfers thus constituted a bottleneck of nutrient transfer on Twin Cays. This is the first comprehensive ecosystem study of nutrient transfers in a mangrove ecosystem, illustrating some mechanisms (e.g. recycling rates, transfer efficiencies) which oligotrophic systems use in order to build up biomass and food webs spanning various trophic levels.

New frontiers in gut nutrient sensor research: nutrient sensors in the gastrointestinal tract: modulation of sweet taste sensitivity by leptin.

PubMed

Horio, Nao; Jyotaki, Masafumi; Yoshida, Ryusuke; Sanematsu, Keisuke; Shigemura, Noriatsu; Ninomiya, Yuzo

2010-01-01

The ability to perceive sweet compounds is important for animals to detect an external carbohydrate source of calories and has a critical role in the nutritional status of animals. In mice, a subset of sweet-sensitive taste cells possesses leptin receptors. Increase of plasma leptin with increasing internal energy storage in the adipose tissue suppresses sweet taste responses via this receptor. The data from recent studies indicate that leptin may also act as a modulator of sweet taste sensation in humans with a diurnal variation in sweet sensitivity. The plasma leptin level and sweet taste sensitivity are proposed to link with post-ingestive plasma glucose level. This leptin modulation of sweet taste sensitivity may influence an individual's preference, ingestive behavior, and absorption of nutrients, thereby playing important roles in regulation of energy homeostasis.

Global implementation of two shared socioeconomic pathways for future sanitation and wastewater flows.

PubMed

van Puijenbroek, P J T M; Bouwman, A F; Beusen, A H W; Lucas, P L

2015-01-01

Households are an important source of nutrient loading to surface water. Sewage systems without or with only primary wastewater treatment are major polluters of surface water. Future emission levels will depend on population growth, urbanisation, increases in income and investments in sanitation, sewage systems and wastewater treatment plants. This study presents the results for two possible shared socioeconomic pathways (SSPs). SSP1 is a scenario that includes improvement of wastewater treatment and SSP3 does not include such improvement, with fewer investments and a higher population growth. The main drivers for the nutrient emission model are population growth, income growth and urbanisation. Under the SSP1 scenario, 5.7 billion people will be connected to a sewage system and for SSP3 this is 5 billion. Nitrogen and phosphorus emissions increase by about 70% under both SSP scenarios, with the largest increase in SSP1. South Asia and Africa have the largest emission increases, in the developed countries decrease the nutrient emissions. The higher emission level poses a risk to ecosystem services.

Manipulating stomatal density enhances drought tolerance without deleterious effect on nutrient uptake.

PubMed

Hepworth, Christopher; Doheny-Adams, Timothy; Hunt, Lee; Cameron, Duncan D; Gray, Julie E

2015-10-01

Manipulation of stomatal density was investigated as a potential tool for enhancing drought tolerance or nutrient uptake. Drought tolerance and soil water retention were assessed using Arabidopsis epidermal patterning factor mutants manipulated to have increased or decreased stomatal density. Root nutrient uptake via mass flow was monitored under differing plant watering regimes using nitrogen-15 ((15) N) isotope and mass spectrometry. Plants with less than half of their normal complement of stomata, and correspondingly reduced levels of transpiration, conserve soil moisture and are highly drought tolerant but show little or no reduction in shoot nitrogen concentrations especially when water availability is restricted. By contrast, plants with over twice the normal density of stomata have a greater capacity for nitrogen uptake, except when water availability is restricted. We demonstrate the possibility of producing plants with reduced transpiration which have increased drought tolerance, with little or no loss of nutrient uptake. We demonstrate that increasing transpiration can enhance nutrient uptake when water is plentiful. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Predation and nutrients drive population declines in breeding waders.

PubMed

Møller, Anders Pape; Thorup, Ole; Laursen, Karsten

2018-04-20

Allee effects are defined as a decline in per capita fitness at low population density. We hypothesized that predation reduces population size of breeding waders and thereby the efficiency of predator deterrence, while total nitrogen through its effects on primary and secondary productivity increases population size. Therefore, nest predation could have negative consequences for population size because nest failure generally results in breeding dispersal and hence reduced local population density. To test these predictions, we recorded nest predation in five species of waders for 4,745 nests during 1987-2015 at the nature reserve Tipperne, Denmark. Predation rates were generally negatively related to conspecific and heterospecific population density, but positively related to overall population density of the entire wader community. Nest predation and population density were related to ground water level, management (grazing and mowing), and nutrients. High nest predation with a time lag of one year resulted in low overall breeding population density, while high nutrient levels resulted in higher population density. These two factors accounted for 86% of the variance in population size, presumably due to effects of nest predation on emigration, while nutrient levels increased the level of vegetation cover and the abundance of food in the surrounding brackish water. These findings are consistent with the hypothesis that predation may reduce population density through negative density dependence, while total nitrogen at adjacent shallow water may increase population size. Nest predation rates were reduced by high ground water level in March, grazing by cattle and mowing that affected access to and susceptibility of nests to predators. These effects can be managed to benefit breeding waders. © 2018 by the Ecological Society of America.

Evaluation of dried vegetables residues for poultry: II. Effects of feeding cabbage leaf residues on broiler performance, ileal digestibility and total tract nutrient digestibility.

PubMed

Mustafa, A F; Baurhoo, B

2017-03-01

A study was conducted to investigate the effects of partial replacing corn and soybean meal with dried cabbage leaf residues (DCR) on broiler growth performance, apparent ileal nutrient digestibility, and apparent total tract nutrient utilization. Dietary treatments include 4 levels of DCR (0, 3, 6, and 9%). Two hundred and twenty-four day-old male broilers were randomly assigned to one of 4 groups (8 cage replicates; 7 birds/cage) and grown over a 35-d experimental period. Results showed that feeding DCR had no effects on daily body weigh gain (average 53.4 g/d), daily feed intake (average 94.9 g/d), and feed conversion ratio (average 1.78 g of feed/g of gain). Inclusion of DCR reduced apparent ileal DM (quadratic effect, P < 0.001), OM (linear effect, P = 0.012), and CP (quadratic effect, P = 0.001) digestibility of younger birds (d 21) while incremental levels of DCR had no effect on apparent ileal nutrient digestibilities of older birds (d 35). Apparent total tract digestibility of DM, OM, and CP increased (linear effect, P < 0.001) as the level of DCR increased. It was concluded that the inclusion of DCR in broiler diets up to 9% had no negative impact on bird performance and apparent ileal digestibility of older birds and improved apparent total tract nutrient digestibility. © 2016 Poultry Science Association Inc.

Proving the Ocean Nourishment Concept

NASA Astrophysics Data System (ADS)

Jones, I. S.

2007-12-01

Vast regions of the sea are barren because of a lack of essential nutrients. Ocean Nourishment is the concept of injecting nutrients into the photic zone of the ocean to store carbon and increase the base of the marine food web. It is elaborated in Jones & Young (1997). The first step in demonstrating this concept is to see if the limiting nutrients can be recognised and provided to the oligotrophic ocean. To this end water samples from three sites were collected in ultraclean polycarbonate culture bottles and enriched with various mixtures of nutrients. They were then placed in a water bath and subjected to natural sunlight for a number of days. Fluorescence levels were measured daily. Previously Thomas (1969) carried out enrichment experiments in and out of high nutrient water in the North Pacific and again Thomas (1970) cultured on the deck of his ship nutrient poor waters in the Pacific. He found nitrogen was the most important limiting nutrient in the poor waters but that micronutrients produced growth in the nutrient rich waters. Ryther and Dunstan (1971) in the Atlantic cultured coastal water with only nitrogen and phosphorus separately. The addition of nitrogen without phosphate produced growth in all cases. To increase the geographic coverage of enrichment experiments, samples were collected off Morocco twice, in the Tasman Sea and in the Sulu Sea. The samples enriched with different concentrations of urea (typically 10 microM) and phosphorous. An increase concentration of chlorophyll is the result of growth of phytoplankton exceeding death and grazing by zooplankton. At five sites an increase of chlorophyll was observed in the macronutrient enriched bottles over that in the control. At the sixth site the control grew at much the same rate as the enriched sample possibly due to contamination by the fluorometer. The maximum chlorophyll level was observed after 4 or 5 days. Replicate samples showed different levels of chlorophyll growths. It was concluded that there were sufficient micronutrients present to support some additional photosynthesis at the sites investigated. These results suggest that it will be practical to nourish broad regions of the ocean to increase primary production. References Jones, I. S. F. and H. E. Young (1997) Engineering a large sustainable world fishery.Environmental Conservation, 24, 99-104. Ryther, J.H. and W. M.Dunstan (1971) Nitrogen, Phosphorus and Eutrophication in the coastal marine environment, Science, 171, 1008-1013. Thomas, W H (1970) Effect of Ammonium and Nitrate Concentration on Chlorophyll increase in Natural Tropical Pacific Phytoplankton Populations, Limnology and Oceanography, 15, 386-394. Thomas, W.H., (1969). Phytoplankton nutrient enrichment experiments off Baja California and in the eastern equatorial Pacific Ocean. J. Fish Res. Bd. Can., 26: 1133-1145. Acknowledgement A Eddington made a number of the obsevations. The Ocean Nourishment Corporation Pty Ltd funded some of the reearch.

Drug-nutrient interactions and their implications for safety evaluations.

PubMed

Conner, M W; Newberne, P M

1984-06-01

In order to assess the relevance of the drug-nutrient interactions described in this chapter to routine toxicologic studies, the range of nutrient concentrations within which these interactions may occur must be compared to the range of nutrient concentrations found in routinely used rodent diets. While obviously deficient levels of some nutrients were supplied to demonstrate some of the interactions, others occur when the nutrients are present in adequate or excess levels, such as might be found in commercially available diets. These diets are known to vary from batch to batch in nutrient content. A lifetime toxicity/carcinogenicity bioassay using rodents may last longer than 2 years, during which time several batches of diet will be used. The variation in diet composition, coupled with inadequate diet description, makes nutrient-toxin interactions not only possible, but difficult to recognize. These considerations raise the practical and philosophical question as to what type of diet is most appropriate for rodents used for safety evaluation of drugs and chemicals. Is it appropriate to use diets that vary unpredictably in nutrient content, that infer a degree of protection against chemical carcinogenesis and which supply some nutrients such as protein in great excess of dietary needs? Is the increase in sensitivity to chemical carcinogens of animals fed purified diets desirable or does this increased sensitivity of the bioassay exceed that required to assess the risk of human exposure? In other words, is the use of purified diets likely to increase the number of false positive results? Proper interpretation and extrapolation of safety evaluation studies requires adequate description of the test system. Given the profound influence of diet on the response to some toxins, the composition of the diet should, ideally, be defined with the same rigor as are the test compound and the strain, age, sex, and housing conditions of the animals. It is likely, however, that natural ingredients diets will continue to be the diets of choice in safety evaluation studies. This is largely due to economic reasons. It is possible, however, to use these diets with greater confidence if open-formula diets are used and the concentration of each nutrient is reported. Consideration should also be given to preparing diets for use in adult and aging rodents, diets in which protein content is reduced.(ABSTRACT TRUNCATED AT 400 WORDS)

Differential sensitivity of spinach and amaranthus to enhanced UV-B at varying soil nutrient levels: association with gas exchange, UV-B-absorbing compounds and membrane damage.

PubMed

Singh, Suruchi; Agrawal, Madhoolika; Agrawal, S B

2013-07-01

The metabolic reasons associated with differential sensitivity of C3 and C4 plant species to enhanced UV-B under varying soil nutrient levels are not well understood. In the present study, spinach (Spinacia oleracea L. var All Green), a C3 and amaranthus (Amaranthus tricolor L. var Pusa Badi Chaulai), a C4 plant were subjected to enhanced UV-B (280-315 nm; 7.2 kJ m(-2) day(-1)) over ambient under varying soil nutrient levels. The nutrient amendments were recommended Nitrogen (N), Phosphorus (P), Potassium (K), 1.5× recommended NPK, 1.5× recommended N and 1.5× recommended K. Enhanced UV-B negatively affected both the species at all nutrient levels, but the reductions varied with nutrient concentration and combinations. Reductions in photosynthetic rate, stomatal conductance and chlorophyll content were significantly more in spinach compared with amaranthus. The reduction in photosynthetic rate was maximum at 1.5× recommended K and minimum in 1.5× NPK amended plants. The oxidative damage to membranes measured in terms of malondialdehyde content was significantly higher in spinach compared with amaranthus. Enhanced UV-B reduced SOD activity in both the plants except in amaranthus at 1.5× recommended K. POX activity increased under enhanced UV-B at all nutrient levels in amaranthus, but only at 1.5× K in spinach. Amaranthus had significantly higher UV-B-absorbing compounds than spinach even under UV-B stress. Lowest reductions in yield and total biomass under enhanced UV-B compared with ambient were observed in amaranthus grown at 1.5× recommended NPK. Enhanced UV-B did not significantly change the nitrogen use efficiency in amaranthus at all NPK levels, but reduced in spinach except at 1.5× K. These findings suggest that the differential sensitivity of the test species under enhanced UV-B at varying nutrient levels is due to varying antioxidative and UV-B screening capacity, and their ability to utilize nutrients. Amaranthus tolerated enhanced UV-B stress more than spinach at all nutrient levels and 1.5× recommended NPK lowered the sensitivity maximally to enhanced UV-B with respect to photosynthesis, biomass and yield. PCA score has also confirmed the lower sensitivity of amaranthus compared with spinach with respect to the measured physiological and biochemical parameters.

Food web efficiency differs between humic and clear water lake communities in response to nutrients and light.

PubMed

Faithfull, C L; Mathisen, P; Wenzel, A; Bergström, A K; Vrede, T

2015-03-01

This study demonstrates that clear and humic freshwater pelagic communities respond differently to the same environmental stressors, i.e. nutrient and light availability. Thus, effects on humic communities cannot be generalized from existing knowledge about these environmental stressors on clear water communities. Small humic lakes are the most numerous type of lake in the boreal zone, but little is known about how these lakes will respond to increased inflows of nutrients and terrestrial dissolved organic C (t-DOC) due to climate change and increased human impacts. Therefore, we compared the effects of nutrient addition and light availability on pelagic humic and clear water lake communities in a mesocosm experiment. When nutrients were added, phytoplankton production (PPr) increased in both communities, but pelagic energy mobilization (PEM) and bacterial production (BP) only increased in the humic community. At low light conditions, the addition of nutrients led to increased PPr only in the humic community, suggesting that, in contrast to the clear water community, humic phytoplankton were already adapted to lower ambient light levels. Low light significantly reduced PPr and PEM in the clear water community, but without reducing total zooplankton production, which resulted in a doubling of food web efficiency (FWE = total zooplankton production/PEM). However, total zooplankton production was not correlated with PEM, PPr, BP, PPr:BP or C:nutrient stoichiometry for either community type. Therefore, other factors such as food chain length, food quality, ultra-violet radiation or duration of the experiment, must have determined total zooplankton production and ultimately FWE.

Simulating the responses of a low-trophic ecosystem in the East China Sea to decadal changes in nutrient load from the Changjiang (Yangtze) River

NASA Astrophysics Data System (ADS)

Wang, Yucheng; Guo, Xinyu; Zhao, Liang

2018-01-01

Using a three-dimensional coupled biophysical model, we simulated the responses of a lowtrophic ecosystem in the East China Sea (ECS) to long-term changes in nutrient load from the Changjiang (Yangtze) River over the period of 1960-2005. Two major factors affected changes in nutrient load: changes in river discharge and the concentration of nutrients in the river water. Increasing or decreasing Changjiang discharge induced different responses in the concentrations of nutrients, phytoplankton, and detritus in the ECS. Changes in dissolved inorganic nitrogen (DIN), silicate (SIL), phytoplankton, and detritus could be identified over a large area of the ECS shelf, but changes in dissolved inorganic phosphate (DIP) were limited to a small area close to the river mouth. The high DIN:DIP and SIL:DIP ratios in the river water were likely associated with the different responses in DIN, DIP, and SIL. As DIP is a candidate limiting nutrient, perturbations in DIP resulting from changes in the Changjiang discharge are quickly consumed through primary production. It is interesting that an increase in the Changjiang discharge did not always lead to an increase in phytoplankton levels in the ECS. Phytoplankton decreases could be found in some areas close to the river mouth. A likely cause of the reduction in phytoplankton was a change in the hydrodynamic field associated with the river plume, although the present model is not suitable for examining the possibility in detail. Increases in DIN and DIP concentrations in the river water primarily led to increases in DIN, DIP, phytoplankton, and detritus levels in the ECS, whereas decreases in the SIL concentration in river water led to lower SIL concentrations in the ECS, indicating that SIL is not a limiting nutrient for photosynthesis, based on our model results from 1960 to 2005. In both of the above-mentioned cases, the sediment accumulation rate of detritus exhibited a large spatial variation near the river mouth, suggesting that core sample data should be carefully interpreted.

Trends in Dietary Supplement Use in a Cohort of Postmenopausal Women From Iowa

PubMed Central

Park, Kyong; Jacobs, David R.

2009-01-01

Although it is widely known that use of dietary supplements is common in the United States, little is known about use patterns among older Americans. The authors examined trends in dietary supplement use and its contribution to total nutrient intake in the Iowa Women's Health Study cohort in 1986 (baseline) and 2004 (follow-up). The proportion of women who reported using dietary supplements increased substantially between baseline (66%) and follow-up (85%). Moreover, a substantial proportion of women reported using multiple dietary supplements, with 27% using 4 or more products in 2004. Dietary supplements contributed substantially to total intake of many nutrients at baseline, and their contribution became relatively greater at follow-up for most nutrients examined. For most nutrients, no decline in intake was observed, as might have been expected in an aging cohort. Rather, intake of many nutrients increased, primarily because of the rising use of dietary supplements. Use of dietary supplements by older individuals is of particular importance because of the potential benefits of maintaining nutrient intake levels despite potentially declining food intake. However, possible risks from obtaining a large proportion of purified nutrients from dietary supplements rather than deriving them from foods should be studied. PMID:19208725

Salmon carcasses increase stream productivity more than inorganic fertilizer pellets: A test on multiple trophic levels in streamside experimental channels

USGS Publications Warehouse

Wipfli, Mark S.; Hudson, John P.; Caouette, John P.; Mitchell, N.L.; Lessard, Joanna L.; Heintz, Ron A.; Chaloner, D.T.

2010-01-01

Inorganic nutrient amendments to streams are viewed as possible restoration strategies for re-establishing nutrients and stream productivity throughout the western coast of North America, where salmon runs and associated marine-derived nutrient subsidies have declined. In a mesocosm experiment, we examined the short-term (6 weeks) comparative effects of artificial nutrient pellets and salmon carcasses, alone (low and high amounts) and in combination, on stream food webs. Response variables included dissolved nutrient concentrations, biofilm ash-free dry mass (AFDM) and chlorophyll-alevels, macroinvertebrate density, growth and body condition of juvenile coho salmon Oncorhynchus kisutch, and whole-body lipid content of invertebrates and juvenile coho salmon. Most of the response variables were significantly influenced by carcass treatment; the only response variable significantly influenced by fertilizer pellet treatment was soluble reactive phosphorus (SRP) concentration. Ammonium-nitrogen concentration was the only response variable affected by both (low and high) levels of carcass treatment; all others showed no significant response to the two carcass treatment levels. Significant treatment × time interactions were observed for all responses except nitrate; for most responses, significant treatment effects were detected at certain time periods and not others. For example, significantly higher SRP concentrations were recorded earlier in the experiment, whereas significant fish responses were observed later. These results provide evidence that inorganic nutrient additions do not have the same ecological effects in streams as do salmon carcasses, potentially because inorganic nutrient additions lack carbon-based biochemicals and macromolecules that are sequestered directly or indirectly by consumers. Salmon carcasses, preferably deposited naturally during spawning migrations, appear to be far superior to inorganic nutrient amendments for sustaining and restoring stream productivity, including fish production, and should be chosen over artificial nutrient additions when feasible and practical.

Saltmarsh plant responses to eutrophication.

PubMed

Johnson, David Samuel; Warren, R Scott; Deegan, Linda A; Mozdzer, Thomas J

2016-12-01

In saltmarsh plant communities, bottom-up pressure from nutrient enrichment is predicted to increase productivity, alter community structure, decrease biodiversity, and alter ecosystem functioning. Previous work supporting these predictions has been based largely on short-term, plot-level (e.g., 1-300 m 2 ) studies, which may miss landscape-level phenomena that drive ecosystem-level responses. We implemented an ecosystem-scale, nine-year nutrient experiment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophication. Our study differed from previous saltmarsh enrichment studies in that we applied realistic concentrations of nitrate (70-100 μM NO 3 - ), the most common form of coastal nutrient enrichment, via tidal water at the ecosystem scale (~60,000 m 2 creeksheds). Our enrichments added a total of 1,700 kg N·creek -1 ·yr -1 , which increased N loading 10-fold vs. reference creeks (low-marsh, 171 g N·m -2 ·yr -1 ; high-marsh, 19 g N·m -2 ·yr -1 ). Nutrients increased the shoot mass and height of low marsh, tall Spartina alterniflora; however, declines in stem density resulted in no consistent increase in aboveground biomass. High-marsh plants S. patens and stunted S. alterniflora did not respond consistently to enrichment. Nutrient enrichment did not shift community structure, contrary to the prediction of nutrient-driven dominance of S. alterniflora and Distichlis spicata over S. patens. Our mild responses may differ from the results of previous studies for a number of reasons. First, the limited response of the high marsh may be explained by loading rates orders of magnitude lower than previous work. Low loading rates in the high marsh reflect infrequent inundation, arguing that inundation patterns must be considered when predicting responses to estuarine eutrophication. Additionally, we applied nitrate instead of the typically used ammonium, which is energetically favored over nitrate for plant uptake. Thus, the form of nitrogen enrichment used, not just N-load, may be important in predicting plant responses. Overall, our results suggest that when coastal eutrophication is dominated by nitrate and delivered via flooding tidal water, aboveground saltmarsh plant responses may be limited despite moderate-to-high water-column N concentrations. Furthermore, we argue that the methodological limitations of nutrient studies must be considered when using results to inform management decisions about wetlands. © 2016 by the Ecological Society of America.

Comparing intake estimations based on food composition data with chemical analysis in Malian women.

PubMed

Koréissi-Dembélé, Yara; Doets, Esmee L; Fanou-Fogny, Nadia; Hulshof, Paul Jm; Moretti, Diego; Brouwer, Inge D

2017-06-01

Food composition databases are essential for estimating nutrient intakes in food consumption surveys. The present study aimed to evaluate the Mali food composition database (TACAM) for assessing intakes of energy and selected nutrients at population level. Weighed food records and duplicate portions of all foods consumed during one day were collected. Intakes of energy, protein, fat, available carbohydrates, dietary fibre, Ca, Fe, Zn and vitamin A were assessed by: (i) estimating the nutrient intake from weighed food records based on an adjusted TACAM (a-TACAM); and (ii) chemical analysis of the duplicate portions. Agreement between the two methods was determined using the Wilcoxon signed-rank test and Bland-Altman plots. Bamako, Mali. Apparently healthy non-pregnant, non-lactating women (n 36) aged 15-36 years. Correlation coefficients between estimated and analysed values ranged from 0·38 to 0·61. At population level, mean estimated and analysed nutrient intakes differed significantly for carbohydrates (203·0 v. 243·5 g/d), Fe (9·9 v. 22·8 mg/d) and vitamin A (356 v. 246 µg retinol activity equivalents). At individual level, all estimated and analysed nutrient intakes differed significantly; the differences tended to increase with higher intakes. The a-TACAM is sufficiently acceptable for measuring average intakes of macronutrients, Ca and Zn at population level in low-intake populations, but not for carbohydrate, vitamin A and Fe intakes, and nutrient densities.

Analysis of the combined effects of lanthanum and acid rain, and their mechanisms, on nitrate reductase transcription in plants.

PubMed

Xia, Binxin; Sun, Zhaoguo; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

2017-04-01

Rare earth element (REE) pollution and acid rain are major global environmental concerns, and their spatial distributions overlap. Thus, both forms of pollution combine to act on plants. Nitrogen is important for plant growth, and nitrate reductase (NR) is a key plant enzyme that catalyzes nitrogen assimilation. Studying the combined effects of REEs and acid rain on plant nitrogen-based nutrients has important environmental significance. Here, soybean (Glycine max) plants, commonly used for toxicological studies, were exposed to lanthanum (La), a REE, and acid rain to study the NR activities and NR transcriptional levels in the roots. To explain how the pollution affected the NR transcriptional level, we simultaneously observed the contents of intracellular La and nutrient elements, protoplast morphology, membrane lipid peroxidation and intracellular pH. A combined treatment of 0.08mmol/L La and pH 4.5 acid rain increased the NR activity, decreased the NR transcriptional level, increased the intracellular nutrient elements' contents and caused deformations in membrane structures. Other combined treatments significantly decreased the aforementioned parameters and caused serious damage to the membrane structures. The variation in the amplitudes of combined treatments was greater than those of individual treatments. Compared with the control and individual treatments, combined treatments increased membrane permeability, the malondialdehyde content, and intracellular H + and La contents, and with an increasing La concentration or acid strength, the change in amplitude increased. Thus, the combined effects on NR gene transcription in soybean seedling roots were related to the intracellular nutrient elements' contents, protoplast morphology, membranous lipid peroxidation, intracellular pH and La content. Copyright © 2016 Elsevier Inc. All rights reserved.

Response of tundra ecosystems to elevated atmospheric carbon dioxide. [Annual report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oechel, W.C.; Grulke, N.E.

1988-12-31

Our past research shows that arctic tussock tundra responds to elevated atmospheric CO{sub 2} with marked increases in net ecosystem carbon flux and photosynthetic rates. However, at ambient temperatures and nutrient availabilities, homeostatic adjustments result in net ecosystem flux rates dropping to those found a contemporary CO{sub 2} levels within three years. Evidence for ecosystem-level acclimation in the first season of elevated CO{sub 2} exposure was found in 1987. Photosynthetic rates of Eriophorum vaginatum, the dominant species, adjusts to elevated CO{sub 2} within three weeks. Past research also indicates other changes potentially important to ecosystem structure and function. Elevated CO{submore » 2} treatment apparently delays senescence and increases the period of positive photosynthetic activity. Recent results from the 1987 field season verify the results obtained in the 1983--1986 field seasons: Elevated CO{sub 2} resulted in increased ecosystem-level flux rates. Regressions fitted to the seasonal flux rates indicate an apparent 10 d extension of positive CO{sub 2} uptake reflecting a delay of the onset of plant dormancy. This delay in senescence could increase the frost sensitivity of the system. Major end points proposed for this research include the effects of elevated CO{sub 2} and the interaction of elevated atmospheric CO{sub 2} with elevated soil temperature and increased nutrient availability on: (1) Net ecosystem CO{sub 2} flux; (2) Net photosynthetic rates; (3) Patterns and resource controls on homeostatic adjustment in the above processes to elevated CO{sub 2}; (4) Plant-nutrient status, litter quality, and forage quality; (5) Soil-nutrient status; (6) Plant-growth pattern and shoot demography.« less

Global-scale patterns of nutrient density and partitioning in forests in relation to climate.

PubMed

Zhang, Kerong; Song, Conghe; Zhang, Yulong; Dang, Haishan; Cheng, Xiaoli; Zhang, Quanfa

2018-01-01

Knowledge of nutrient storage and partitioning in forests is imperative for ecosystem models and ecological theory. Whether the nutrients (N, P, K, Ca, and Mg) stored in forest biomass and their partitioning patterns vary systematically across climatic gradients remains unknown. Here, we explored the global-scale patterns of nutrient density and partitioning using a newly compiled dataset including 372 forest stands. We found that temperature and precipitation were key factors driving the nutrients stored in living biomass of forests at global scale. The N, K, and Mg stored in living biomass tended to be greater in increasingly warm climates. The mean biomass N density was 577.0, 530.4, 513.2, and 336.7 kg/ha for tropical, subtropical, temperate, and boreal forests, respectively. Around 76% of the variation in biomass N density could be accounted by the empirical model combining biomass density, phylogeny (i.e., angiosperm, gymnosperm), and the interaction of mean annual temperature and precipitation. Climate, stand age, and biomass density significantly affected nutrients partitioning at forest community level. The fractional distribution of nutrients to roots decreased significantly with temperature, suggesting that forests in cold climates allocate greater nutrients to roots. Gymnosperm forests tended to allocate more nutrients to leaves as compared with angiosperm forests, whereas the angiosperm forests distributed more nutrients in stems. The nutrient-based Root:Shoot ratios (R:S), averaged 0.30 for R:S N , 0.36 for R:S P , 0.32 for R:S K , 0.27 for R:S Ca , and 0.35 for R:S Mg , respectively. The scaling exponents of the relationships describing root nutrients as a function of shoot nutrients were more than 1.0, suggesting that as nutrient allocated to shoot increases, nutrient allocated to roots increases faster than linearly with nutrient in shoot. Soil type significantly affected the total N, P, K, Ca, and Mg stored in living biomass of forests, and the Acrisols group displayed the lowest P, K, Ca, and Mg. © 2017 John Wiley & Sons Ltd.

Children's Sensitivity to External Food Cues: How Distance to Serving Bowl Influences Children's Consumption

ERIC Educational Resources Information Center

Musher-Eizenman, Dara R.; Young, Kathleen M.; Laurene, Kimberly; Galliger, Courtney; Hauser, Jessica; Wagner Oehlhof, Marissa

2010-01-01

Overweight is increasing in children, leading to negative health consequences. Children also lack appropriate levels of important vitamins and nutrients in their diets. Environmental cues, such as food proximity, have been shown to influence consumption rates in adults. The present study has tested whether proximity to either a nutrient-dense or…

Impact of harvesting and atmospheric pollution on nutrient depletion of eastern US hardwood forests

Treesearch

M.B. Adams; J.A. Burger; A.B. Jenkins; L. Zelazny

2000-01-01

The eastern hardwood forests of the US may be threatened by the changing atmospheric chemistry and by changes in harvesting levels. Many studies have documented accelerated base cation losses with intensive forest harvesting. Acidic deposition can also alter nutrient cycling in these forests. The combination of increased harvesting, shorter rotations, and more...

Are physical activity levels linked to nutrient adequacy? Implications for cancer risk.

PubMed

Csizmadi, Ilona; Kelemen, Linda E; Speidel, Thomas; Yuan, Yan; Dale, Laura C; Friedenreich, Christine M; Robson, Paula J

2014-01-01

Cancer prevention guidelines recommend a healthy body mass index, physical activity, and nutrient intake from food rather than supplements. Sedentary individuals may restrict energy intake to prevent weight gain and in so doing may compromise nutritional intake. We conducted a cross-sectional analysis to determine if adequacy of micronutrients is linked to physical activity levels (PALs) in healthy-weight adults. Tomorrow Project participants in Alberta, Canada (n = 5333), completed past-year diet and physical activity questionnaires. The percent meeting Dietary Reference Intakes (DRIs) was reported across low and high PAL groups, and the relation between PAL and percent achieved DRI was determined using multiple linear regression analyses. Overall, <50% of healthy-weight participants met DRIs for folate, calcium, and vitamin D. Percent achieved DRI increased linearly with increasing PAL in both genders (P < 0.01). A hypothetical increase in PAL from 1.4 to 1.9 was associated with a DRI that was 8%-13% higher for folate and vitamin C (men) and 5%-15% higher for calcium and iron (women). Healthy-weight adults at higher PALs appear more likely to meet DRIs for potential cancer-preventing nutrients. The benefits of higher PALs may extend beyond the usual benefits attributed to physical activity to include having a more favorable impact on nutrient adequacy.

Colonic luminal microbiota and bacterial metabolite composition in pregnant Huanjiang mini-pigs: effects of food composition at different times of pregnancy

PubMed Central

Kong, Xiang-feng; Ji, Yu-jiao; Li, Hua-wei; Zhu, Qian; Blachier, F.; Geng, Mei-mei; Chen, Wen; Yin, Yu-long

2016-01-01

The gut harbours diverse and complex microbiota, which influence body health including nutrient metabolism, immune development, and protection from pathogens. Pregnancy is associated with immune and metabolic changes that might be related to microbiota compositional dynamics. We therefore investigated the colonic luminal bacteria community in Huanjiang mini-pigs fed diets with different nutrient levels from the first to third trimester of pregnancy. The concentrations of intestinal metabolites including short-chain fat acids, NH3-N, indole, skatole, and bioamines were also determined. We found that the colonic bacteria species richness estimators (Chao1 and ACE) decreased with increased gestational age. The dominant phyla identified were Firmicutes and Bacteroidetes; the dominant genera were Lactobacillus, Treponema, Ruminococcus, Clostridium, and Prevotella. In addition, microbiota displayed spatial and temporal heterogeneity in composition, diversity, and species abundance in different colonic segments from the first to third trimester of pregnancy. Furthermore, the bacterial metabolites also changed according to the diet used and the pregnancy stage. These findings suggest that colonic bacteria richness decreased as gestational age increased, and that the higher nutrient level diet increased the production of metabolites related to nitrogen metabolism. However, although the higher nutrient diet was associated with pregnancy syndrome, causal links remain to be determined. PMID:27917879

Tracking Se Assimilation and Speciation through the Rice Plant – Nutrient Competition, Toxicity and Distribution

PubMed Central

Eiche, Elisabeth; Riemann, Michael; Nick, Peter; Winkel, Lenny H. E.; Göttlicher, Jörg; Steininger, Ralph; Brendel, Rita; von Brasch, Matthias; Konrad, Gabriele; Neumann, Thomas

2016-01-01

Up to 1 billion people are affected by low intakes of the essential nutrient selenium (Se) due to low concentrations in crops. Biofortification of this micronutrient in plants is an attractive way of increasing dietary Se levels. We investigated a promising method of Se biofortification of rice seedlings, as rice is the primary staple for 3 billion people, but naturally contains low Se concentrations. We studied hydroponic Se uptake for 0–2500 ppb Se, potential phyto-toxicological effects of Se and the speciation of Se along the shoots and roots as a function of added Se species, concentrations and other nutrients supplied. We found that rice germinating directly in a Se environment increased plant-Se by factor 2–16, but that nutrient supplementation is required to prevent phyto-toxicity. XANES data showed that selenite uptake mainly resulted in the accumulation of organic Se in roots, but that selenate uptake resulted in accumulation of selenate in the higher part of the shoot, which is an essential requirement for Se to be transported to the grain. The amount of organic Se in the plant was positively correlated with applied Se concentration. Our results indicate that biofortification of seedlings with selenate is a successful method to increase Se levels in rice. PMID:27116220

Assessment of acidification and eutrophication in the coastal waters of Bolinao, Pangasinan, Philippines

NASA Astrophysics Data System (ADS)

Lagumen, M. C. T.; San Diego-McGlone, M. L.

2014-12-01

Ocean acidification is becoming a global concern due to its potential effects on marine resources. In coastal areas, an emerging problem is ocean acidicification due to eutrophication resulting from human activities. The coastal water of Bolinao, Pangasinan, Philippines has become eutrophic due to increased nutrient loading from unconsumed fish feeds in fish cages. Mariculture is a big industry in Bolinao. In over a decade, the area has experienced decreased oxygen levels leading to hypoxia, fish kills, and algal blooms. The decomposition of organic matter from unconsumed fish feeds results not only to high nutrient buildup but also increased CO2 and acidity in the area. Nutrients (ammonia, nitrate, nitrite, phosphate and silicate), total alkalinity (TA), dissolved inorganic carbon (DIC), pH, dissolved oxygen (DO), aragonite saturation state (Ωarg) and partial pressure of carbon dioxide (pCO2) were measured to determine the combined effect of acidification and eutrophication in Bolinao. Monitoring results have shown an increase in nutrients by 30% to 70% in over a decade. Stratified water during rainy season have resulted in low DO (<5.5) and acidic water (<7.5) with high pCO2 level (>900 μatm). Shallow stations with poor water circulation have shown undersaturated aragonite state (< 2.0) and high pCO2 levels of 800 matm. The eutrophic and acidified coastal waters of Bolinao are already affecting the seagrass and coral reef ecosystems in the area.

Dietary nutrient levels regulate protein and carbohydrate intake, gluconeogenic/glycolytic flux and blood trehalose level in the insect Manduca sexta L.

PubMed

Thompson, S N; Borchardt, D B; Wang, L-W

2003-03-01

This study examined the effects of dietary casein and sucrose levels on nutrient intake, and distinguished the effects of carbohydrate and protein consumption on growth, fat content, pyruvate metabolism and blood trehalose level of 5th instar Manduca sexta larvae. Growth increased with increasing casein consumption but was unaffected by carbohydrate intake. Fat content also increased with carbohydrate consumption, but on carbohydrate-free diets fat content increased with increased protein consumption. Blood trehalose level and pyruvate metabolism were examined by nuclear magnetic resonance spectroscopy analysis of blood following administration of (3-(13)C)pyruvate. On diets containing sucrose, blood trehalose increased with increasing carbohydrate intake, and on most diets trehalose was synthesized entirely from dietary sucrose. Pyruvate cycling, indicated by the alanine C2/C3 (13)C enrichment ratio, increased with carbohydrate consumption reflecting increased glycolysis, and pyruvate decarboxylation exceeded carboxylation on all sucrose diets. Larvae that consumed <75 mg/day sucrose were gluconeogenic, based on the [2 (trehalose C6)(Glx C3/C2)]/alanine C2] (13)C enrichment ratio. On carbohydrate-free diets, blood trehalose levels were low and maintained entirely by gluconeogenesis. Blood trehalose level increased with increasing protein intake. Pyruvate cycling was very low, although many insects displayed higher levels of pyruvate decarboxylation than carboxylation. All gluconeogenic larvae displayed alanine (13)C enrichment ratios <0.35 and had blood trehalose levels <50 mM.

Inadequacy of nutrients intake among pregnant women in the deep south of Thailand.

PubMed

Sukchan, Phnom; Liabsuetrakul, Tippawan; Chongsuvivatwong, Virasakdi; Songwathana, Praneed; Sornsrivichai, Vosasit; Kuning, Metta

2010-09-24

The deep south of Thailand is an area which has been affected by violence since 2004, yet the concurrent coverage of antenatal care has remained at over 90%. Our study aimed to describe the prevalence of nutrient inadequacy among pregnant women who attended antenatal care clinics in hospitals in the study area and assess factors associated with nutrient inadequacy. Pregnant women from four participating hospitals located in lower southern Thailand were surveyed during January-December 2008. Nutrient intake was estimated based on information provided by the women on the amount, type and frequency of various foods eaten. Logistic regression was used to assess individual and community factors associated with inadequate nutrient intake, defined as less than two thirds of the recommended dietary allowance (RDA). The prevalence of carbohydrate, protein, fat, calories, calcium, phosphorus, iron, thiamine, riboflavin, retinol, niacin, vitamin C, folic acid and iodine inadequacy was 86.8%, 59.2%, 78.0%, 83.5%, 55.0%, 29.5%, 45.2%, 85.0%, 19.2%, 3.8%, 43.2%, 0.8%, 0.0% and 0.8%, respectively. Maternal age, education level, gestational age at enrollment and pre-pregnancy body mass index and level of violence in the district were significantly associated with inadequacy of carbohydrate, protein, phosphorus, iron, thiamine and niacin intake. Nutrient intake inadequacy among pregnant women was common in this area. Increasing levels of violence was associated with nutrient inadequacy in addition to individual factors.

Nutrients stimulate leaf breakdown rates and detritivore biomass: Bottom-up effects via heterotrophic pathways

USGS Publications Warehouse

Greenwood, J.L.; Rosemond, A.D.; Wallace, J.B.; Cross, W.F.; Weyers, H.S.

2007-01-01

Most nutrient enrichment studies in aquatic systems have focused on autotrophic food webs in systems where primary producers dominate the resource base. We tested the heterotrophic response to long-term nutrient enrichment in a forested, headwater stream. Our study design consisted of 2 years of pretreatment data in a reference and treatment stream and 2 years of continuous nitrogen (N) + phosphorus addition to the treatment stream. Studies were conducted with two leaf species that differed in initial C:N, Rhododendron maximum (rhododendron) and Acer rubrum (red maple). We determined the effects of nutrient addition on detrital resources (leaf breakdown rates, litter C:N and microbial activity) and tested whether nutrient enrichment affected macroinvertebrate consumers via increased biomass. Leaf breakdown rates were ca. 1.5 and 3?? faster during the first and second years of enrichment, respectively, in the treatment stream for both leaf types. Microbial respiration rates of both leaf types were 3?? higher with enrichment, and macroinvertebrate biomass associated with leaves increased ca. 2-3?? with enrichment. The mass of N in macroinvertebrate biomass relative to leaves tended to increase with enrichment up to 6?? for red maple and up to 44?? for rhododendron leaves. Lower quality (higher C:N) rhododendron leaves exhibited greater changes in leaf nutrient content and macroinvertebrate response to nutrient enrichment than red maple leaves, suggesting a unique response by different leaf species to nutrient enrichment. Nutrient concentrations used in this study were moderate and equivalent to those in streams draining watersheds with altered land use. Thus, our results suggest that similarly moderate levels of enrichment may affect detrital resource quality and subsequently lead to altered energy and nutrient flow in detrital food webs. ?? 2006 Springer-Verlag.

Colony patterning and collective hyphal growth of filamentous fungi

NASA Astrophysics Data System (ADS)

Matsuura, Shu

2002-11-01

Colony morphology of wild and mutant strains of Aspergillus nidulans at various nutrient and agar levels was investigated. Two types of colony patterning were found for these strains. One type produced uniform colonies at all nutrient and agar levels tested, and the other exhibited morphological change into disordered ramified colonies at low nutrient levels. Both types showed highly condensed compact colonies at high nutrient levels on low agar media that was highly diffusive. Disordered colonies were found to develop with low hyphal extension rates at low nutrient levels. To understand basic pattern selection rules, a colony model with three parameters, i.e., the initial nutrient level and the step length of nutrient random walk as the external parameters, and the frequency of nutrient uptake as an internal parameter, was constructed. At low nutrient levels, with decreasing nutrient uptake frequency under diffusive conditions, the model colony exhibited onsets of disordered ramification. Further, in the growth process of A. nidulans, reduction of hyphal extension rate due to a population effect of hyphae was found when hyphae form three-dimensional dense colonies, as compared to the case in which hyphal growth was restricted into two-dimensional space. A hyphal population effect was introduced in the colony model. Thickening of colony periphery due to the population effect became distinctive as the nutrient diffusion effect was raised at high nutrient levels with low hyphal growth rate. It was considered that colony patterning and onset of disorder were strongly governed by the combination of nutrient diffusion and hyphal growth rate.

Coastal eutrophication as a driver of salt marsh loss.

PubMed

Deegan, Linda A; Johnson, David Samuel; Warren, R Scott; Peterson, Bruce J; Fleeger, John W; Fagherazzi, Sergio; Wollheim, Wilfred M

2012-10-18

Salt marshes are highly productive coastal wetlands that provide important ecosystem services such as storm protection for coastal cities, nutrient removal and carbon sequestration. Despite protective measures, however, worldwide losses of these ecosystems have accelerated in recent decades. Here we present data from a nine-year whole-ecosystem nutrient-enrichment experiment. Our study demonstrates that nutrient enrichment, a global problem for coastal ecosystems, can be a driver of salt marsh loss. We show that nutrient levels commonly associated with coastal eutrophication increased above-ground leaf biomass, decreased the dense, below-ground biomass of bank-stabilizing roots, and increased microbial decomposition of organic matter. Alterations in these key ecosystem properties reduced geomorphic stability, resulting in creek-bank collapse with significant areas of creek-bank marsh converted to unvegetated mud. This pattern of marsh loss parallels observations for anthropogenically nutrient-enriched marshes worldwide, with creek-edge and bay-edge marsh evolving into mudflats and wider creeks. Our work suggests that current nutrient loading rates to many coastal ecosystems have overwhelmed the capacity of marshes to remove nitrogen without deleterious effects. Projected increases in nitrogen flux to the coast, related to increased fertilizer use required to feed an expanding human population, may rapidly result in a coastal landscape with less marsh, which would reduce the capacity of coastal regions to provide important ecological and economic services.

Supplementation of laying-hen feed with palm tocos and algae astaxanthin for egg yolk nutrient enrichment.

PubMed

Walker, Laurie A; Wang, Tong; Xin, Hongwei; Dolde, David

2012-02-29

Adding supplements to hen feed can increase egg nutritional value. Astaxanthin, tocotrienols, and tocopherols are potent antioxidants that provide health benefits to humans. We hypothesized that the addition of these nutrients to hen feed would result in an increased nutrient content in egg yolk with minimum changes in functional properties. Laying hens (Hy-Line W-36 breed) were fed four diets with different supplementation levels of palm toco concentrate and algae biomass containing astaxanthin for 8 weeks. Egg yolks were analyzed for physical, chemical, and functional properties. The feed with the highest nutrient concentration was also studied for stability of these antioxidants using the Arrhenius approach. No significant differences were observed in functional properties except for emulsification capacity and sensory characteristics among eggs from different diet treatments. Changes in egg yolk color reached the maximum values at day 8. Incorporation of tocopherols and tocotrienols increased until day 8, astaxanthin incorporation increased until day 10, and all decreased thereafter. Feed nutrients resulted in a dose-response relationship of these compounds in the egg yolk. The transfer efficiency ranged from 0 to 9.9% for tocotrienols and tocopherols and from 7.6 to 14.9% for astaxanthin at their peak values. Results of the Arrhenius accelerated stability study showed significant differences in the shelf life of various nutrients, and these results can be used to properly formulate and store the feed materials.

Nutrient excretion, phosphorus characterization, and phosphorus solubility in excreta from broiler chicks fed diets containing graded levels of wheat distillers grains with solubles.

PubMed

Leytem, A B; Kwanyuen, P; Thacker, P

2008-12-01

Increased interest in ethanol production in North America has led to increased production of distillers dried grains with solubles (DDGS), the majority of which are fed to livestock. To determine the impact of including wheat DDGS in broiler diets on nutrient excretion and P characterization and solubility, 125 one-day-old male broiler chicks were fed wheat- and soybean meal-based diets containing 0, 5, 10, 15, or 20% wheat DDGS. There were 5 replicate pens per treatment, with 5 birds per pen arranged in a randomized block design. Apparent retention of both N and P were determined by using the indicator method. Nutrients excreted per kilogram of DM intake were also calculated. Characterization of excreta P was determined by (31)P-solution nuclear magnetic resonance spectroscopy, and water-soluble P (WSP) was determined by extraction of excreta with deionized water. The apparent retention of both N (P < 0.001) and P (P < 0.008) decreased linearly with increasing inclusion rates of DDGS from 0 to 20%. The nutrient output per kilogram of DM intake increased linearly with increased DDGS inclusion rate for N (P < 0.04), P (P < 0.0001), and WSP (P < 0.0003). As the inclusion rate of DDGS increased, the P concentration in excreta increased (P < 0.008), whereas excreta phytate P concentrations decreased (P < 0.01), which led to an increase in WSP and the fraction of total P that was soluble. Because the inclusion of DDGS in poultry diets increased N and P output, as well as the solubility of P excreted, care should be taken when including high levels of DDGS in poultry diets, because increases in N and P excretion are a concern from an environmental standpoint.

Nutritional strategies to cope with reduced litter weight gain and total tract digestibility in lactating sows.

PubMed

Álvarez-Rodríguez, J; Mir, L; Seradj, A R; Morazán, H; Balcells, J; Babot, D

2017-10-01

Twelve lactating sows were used to evaluate the effects of reducing dietary crude protein (CP) (14% vs. 12%) and increasing neutral detergent fibre (NDF) levels (18% vs. 22%) on litter performance, total tract apparent digestibility and manure composition in a 4 × 4 latin square arrangement during a 36-day lactation period. Diets were isoenergetic (2.9 Mcal ME/kg) and had similar total lysine content (0.9%). In addition, a second aim was to compare a reference external marker method (Cr 2 O 3 ) with an internal feed marker [acid-insoluble ash (AIA)] for the calculation of apparent total tract digestibility of nutrients in lactating sows. The reduction of dietary CP level in lactating sows had no effect on either live-weight or backfat thickness or apparent total tract digestibility of nutrients. However, the piglets' average daily gain (ADG) was reduced in low dietary CP diets, which suggests that sows reduced milk production due to an underestimation of certain essential amino acid requirements (e.g. valine). The increase of dietary NDF level did not affect sow and litter performance. Nevertheless, the total tract apparent digestibility of organic matter, CP and carbohydrates was reduced, and ether extract digestion was increased in high NDF compared to normal NDF diets equally balanced for ME and lysine content. The coefficients of total tract apparent digestibility of nutrients in lactating sows were greater when using AIA compared to Cr 2 O 3 marker, regardless of dietary CP or NDF level, but their coefficients of variation were lower in the former than in the latter. In lactating sows, a trade-off between litter performance and nutrient digestion is established when reducing dietary CP or increasing NDF levels while maintaining similar lysine content through synthetic amino acids and balancing metabolizable energy through dietary fat sources. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Wastewater Treatment Energy Recovery Potential For Adaptation To Global Change: An Integrated Assessment

NASA Astrophysics Data System (ADS)

Breach, Patrick A.; Simonovic, Slobodan P.

2018-04-01

Approximately 20% of wastewaters globally do not receive treatment, whereas wastewater discharges are projected to increase, thereby leading to excessive water quality degradation of surface waters on a global scale. Increased treatment could help alleviate water quality issues by constructing more treatment plants; however, in many areas there exist economic constraints. Energy recovery methods including the utilization of biogas and incineration of biosolids generated during the treatment process may help to alleviate treatment costs. This study explores the potential for investments in energy recovery from wastewater to increase treatment levels and thus improve surface water quality. This was done by examining the relationships between nutrient over-enrichment, wastewater treatment, and energy recovery at a global scale using system dynamics simulation as part of the ANEMI integrated assessment model. The results show that a significant amount of energy can be recovered from wastewater, which helps to alleviate some of the costs of treatment. It was found that wastewater treatment levels could be increased by 34%, helping to offset the higher nutrient loading from a growing population with access to improved sanitation. The production of renewable natural gas from biogas was found to have the potential to prolong the depletion of natural gas resources used to produce electricity and heat. It is recommended that agricultural nutrient discharges be better managed to help reduce nutrient over-enrichment on global scale. To increase the utility of the simulation, a finer spatial scale should be used to consider regional treatment, economic, and water quality characteristics.

Wastewater Treatment Energy Recovery Potential For Adaptation To Global Change: An Integrated Assessment.

PubMed

Breach, Patrick A; Simonovic, Slobodan P

2018-04-01

Approximately 20% of wastewaters globally do not receive treatment, whereas wastewater discharges are projected to increase, thereby leading to excessive water quality degradation of surface waters on a global scale. Increased treatment could help alleviate water quality issues by constructing more treatment plants; however, in many areas there exist economic constraints. Energy recovery methods including the utilization of biogas and incineration of biosolids generated during the treatment process may help to alleviate treatment costs. This study explores the potential for investments in energy recovery from wastewater to increase treatment levels and thus improve surface water quality. This was done by examining the relationships between nutrient over-enrichment, wastewater treatment, and energy recovery at a global scale using system dynamics simulation as part of the ANEMI integrated assessment model. The results show that a significant amount of energy can be recovered from wastewater, which helps to alleviate some of the costs of treatment. It was found that wastewater treatment levels could be increased by 34%, helping to offset the higher nutrient loading from a growing population with access to improved sanitation. The production of renewable natural gas from biogas was found to have the potential to prolong the depletion of natural gas resources used to produce electricity and heat. It is recommended that agricultural nutrient discharges be better managed to help reduce nutrient over-enrichment on global scale. To increase the utility of the simulation, a finer spatial scale should be used to consider regional treatment, economic, and water quality characteristics.

Responses of Wheat Yield, Macro- and Micro-Nutrients, and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain.

PubMed

Wang, Fan; Wang, Zhaohui; Kou, Changlin; Ma, Zhenghua; Zhao, Dong

2016-01-01

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn.

Responses of Wheat Yield, Macro- and Micro-Nutrients, and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain

PubMed Central

Wang, Fan; Wang, Zhaohui; Kou, Changlin; Ma, Zhenghua; Zhao, Dong

2016-01-01

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn. PMID:26771517

Contribution of Dietary Supplements to Nutritional Adequacy in Race/Ethnic Population Subgroups in the United States.

PubMed

Blumberg, Jeffrey B; Frei, Balz; Fulgoni, Victor L; Weaver, Connie M; Zeisel, Steven H

2017-11-28

The U.S. Centers for Disease Control and Prevention has reported that nutritional deficiencies in the U.S. population vary by age, gender, and race/ethnicity, and could be as high as nearly one third of certain population groups. Based on nationally representative data in 10,698 adults from National Health and Nutrition Examination Surveys (NHANES) primarily from 2009-2012, assessments were made of race/ethnic differences in the impact of dietary supplements on nutrient intake and prevalence of inadequacies. Compared to food alone, use of any dietary supplement plus food was associated with significantly higher intakes of 14 to 16 of 19 nutrients examined in all race/ethnic groups; and significantly ( p < 0.01) reduced rates of inadequacy for 8/17 nutrients examined in non-Hispanic whites, but only 3-4/17 nutrients (calcium, and vitamins A, D, and E) for other race/ethnic groups. Across race/ethnic groups an increased prevalence of intakes above the Tolerable Upper Intake Level (UL) was seen for 1-9/13 nutrients, but all were less than 5% of the population. In conclusion, use of dietary supplements is associated with increased micronutrient intake, decreased nutrient inadequacies, and slight increases in prevalence above the UL in all race/ethnicities examined, with greater benefits among non-Hispanic whites.

Contribution of Dietary Supplements to Nutritional Adequacy in Various Adult Age Groups.

PubMed

Blumberg, Jeffrey B; Frei, Balz; Fulgoni, Victor L; Weaver, Connie M; Zeisel, Steven H

2017-12-06

Many Americans have inadequate intakes of several nutrients. The Dietary Guidelines for Americans 2015-2020 specifically identified vitamins A, C, D and E, calcium, magnesium, iron, potassium, choline and fiber as "underconsumed nutrients". Based on nationally representative data in 10,698 adults from National Health and Nutrition Examination Surveys (NHANES), 2009-2012, assessments were made of age-group differences in the impact of dietary supplements on nutrient intake and inadequacies. Compared to food alone, use of any dietary supplement plus food was associated with significantly ( p < 0.01) higher intakes of 15-16 of 19 nutrients examined in all age groups; and significantly reduced rates of inadequacy for 10/17, 8/17 and 6/17 nutrients examined among individuals age ≥71, 51-70 and 19-50 years, respectively. Compared to the other age groups, older adults (≥71 years) had lower rates of inadequacy for iron and vitamins A, C, D and E, but higher rates for calcium. An increased prevalence of intakes above the Tolerable Upper Intake Level was seen for 8-9 of 13 nutrients, but were mostly less than 5% of the population. In conclusion, dietary supplement use is associated with increased micronutrient intake, decreased inadequacies, and slight increases in prevalence above the UL, with greater benefits seen among older adults.

Detection of wine grape nutrient levels using visible and near infrared 1nm spectral resolution remote sensing

NASA Astrophysics Data System (ADS)

Anderson, Grant; van Aardt, Jan; Bajorski, Peter; Vanden Heuvel, Justine

2016-05-01

The grape industry relies on regular crop assessment to aid in the day-to-day and seasonal management of their crop. More specifically, there are six key nutrients of interest to viticulturists in the growing of wine grapes, namely nitrogen, potassium, phosphorous, magnesium, zinc and boron. Traditional methods of determining the levels of these nutrients are through collection and chemical analysis of petiole samples from the grape vines themselves. We collected ground-level observations of the spectra of the grape vines, using a hyperspectral spectrometer (0.4-2.5um), at the same time that petioles samples were harvested. We then interpolated the data into a consistent 1 nm spectral resolution before comparing it to the nutrient data collected. This nutrient data came from both the industry standard petiole analysis, as well as an additional leaf-level analysis. The data were collected for two different grape cultivars, both during bloom and veraison periods to provide variability, while also considering the impact of temporal/seasonal change. A narrow-band NDI (Normalized Difference Index) approach, as well as a simple ratio index, was used to determine the correlation of the reflectance data to the nutrient data. This analysis was limited to the silicon photodiode range to increase the utility of our approach for wavelength-specific cameras (via spectral filters) in a low cost drone platform. The NDI generated correlation coefficients were as high as 0.80 and 0.88 for bloom and veraison, respectively. The ratio index produced correlation coefficient results that are the same at two decimal places with 0.80 and 0.88. These results bode well for eventual non-destructive, accurate and precise assessment of vineyard nutrient status.

Indirect effects of predators control herbivore richness and abundance in a benthic eelgrass (Zostera marina) mesograzer community.

PubMed

Amundrud, Sarah L; Srivastava, Diane S; O'Connor, Mary I

2015-07-01

Herbivore communities can be sensitive to changes in predator pressure (top-down effects) and resource availability (bottom-up effects) in a wide range of systems. However, it remains unclear whether such top-down and bottom-up effects reflect direct impacts of predators and/or resources on herbivores, or are indirect, reflecting altered interactions among herbivore species. We quantified direct and indirect effects of bottom-up and top-down processes on an eelgrass (Zostera marina) herbivore assemblage. In a field experiment, we factorially manipulated water column nutrients (with Osmocote(™) slow-release fertilizer) and predation pressure (with predator exclusion cages) and measured the effects on herbivore abundance, richness and beta diversity. We examined likely mechanisms of community responses by statistically exploring the response of individual herbivore species to trophic manipulations. Predators increased herbivore richness and total abundance, in both cases through indirect shifts in community composition. Increases in richness occurred through predator suppression of common gammarid amphipod species (Monocorophium acherusicum and Photis brevipes), permitting the inclusion of rarer gammarid species (Aoroides columbiae and Pontogeneia rostrata). Increased total herbivore abundance reflected increased abundance of a caprellid amphipod species (Caprella sp.), concurrent with declines in the abundance of other common species. Furthermore, predators decreased beta diversity by decreasing variability in Caprella sp. abundance among habitat patches. Osmocote(™) fertilization increased nutrient concentrations locally, but nutrients dissipated to background levels within 3 m of the fertilizer. Nutrient addition weakly affected the herbivore assemblage, not affecting richness and increasing total abundance by increasing one herbivore species (Caprella sp.). Nutrient addition did not affect beta diversity. We demonstrated that assemblage-level effects of trophic manipulations on community structure are the result of distinct and often indirect responses of herbivore species. These results underscore the importance of understanding herbivore-herbivore interactions in a system commonly subjected to both eutrophication and overfishing. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Effects of Controlled-Release Fertilizer on Leaf Area Index and Fruit Yield in High-Density Soilless Tomato Culture Using Low Node-Order Pinching

PubMed Central

Kinoshita, Takafumi; Yano, Takayoshi; Sugiura, Makoto; Nagasaki, Yuji

2014-01-01

To further development of a simplified fertigation system using controlled-release fertilizers (CRF), we investigated the effects of differing levels of fertilizers and plant density on leaf area index (LAI), fruit yields, and nutrient use in soilless tomato cultures with low node-order pinching and high plant density during spring-summer (SS), summer-fall (SF), and fall-winter (FW) seasons. Plants were treated with 1 of 3 levels of CRF in a closed system, or with liquid fertilizer (LF) with constant electrical conductivity (EC) in a drip-draining system. Two plant densities were examined for each fertilizer treatment. In CRF treatments, LAI at pinching increased linearly with increasing nutrient supply for all cropping seasons. In SS, both light interception by plant canopy at pinching and total marketable fruit yield increased linearly with increasing LAI up to 6 m2·m−2; the maximization point was not reached for any of the treatments. In FW, both light interception and yield were maximized at an LAI of approximately 4. These results suggest that maximizing the LAI in SS and FW to the saturation point for light interception is important for increasing yield. In SF, however, the yield maximized at an LAI of approximately 3, although the light interception linearly increased with increasing LAI, up to 4.5. According to our results, the optimal LAI at pinching may be 6 in SS, 3 in SF, and 4 in FW. In comparing LAI values with similar fruit yield, we found that nutrient supply was 32−46% lower with the CRF method than with LF. In conclusion, CRF application in a closed system enables growers to achieve a desirable LAI to maximize fruit yield with a regulated amount of nutrient supply per unit area. Further, the CRF method greatly reduced nutrient use without decreasing fruit yield at similar LAIs, as compared to the LF method. PMID:25402478

[Effect of atmospheric CO2 concentration and nitrogen application level on absorption and transportation of nutrient elements in oilseed rape].

PubMed

Wang, Wen-ming; Zhang, Zhen-hua; Song, Hai-xing; Liu, Qiang; Rong, Xiang-min; Guan, Chun-yun; Zeng, Jing; Yuan, Dan

2015-07-01

Effect of elevated atmospheric-CO2 (780 µmol . mol-1) on the absorption and transportation of secondary nutrient elements (calcium, magnesium, sulphur) and micronutrient elements (iron, manganese, zinc, molybdenum and boron) in oilseed rape at the stem elongation stage were studied by greenhouse simulated method. Compared with the ambient CO2 condition, the content of Zn in stem was increased and the contents of other nutrient elements were decreased under the elevated atmospheric-CO2 with no nitrogen (N) application; the contents of Ca, S, B and Zn were increased, and the contents of Mg, Mn, Mo and Fe were decreased under the elevated atmospheric CO2 with N application (0.2 g N . kg-1 soil); except the content of Mo in leaf was increased, the contents of other nutrient elements were decreased under the elevated atmospheric-CO2 with two levels of N application. Compared with the ambient CO2 condition, the amounts of Ca and S relative to the total amount of secondary nutrient elements in stem and the amounts of B and Zn relative to the total amount of micronutrient elements in stem were increased under the elevated-CO2 treatment with both levels of N application, and the corresponding values of Mg, Fe, Mn and Mo were decreased; no-N application treatment increased the proportion of Ca distributed into the leaves, and the proportion of Mg distributed into leaves was increased by the normal-N application level; the proportions of Mn, Zn and Mo distributed into the leaves were increased at both N application levels. Without N application, the elevation of atmospheric CO2 increased the transport coefficients of SFe, Mo and SS,B, but decreased the transport coefficients of SMg,Fe, SMg, Mn and SS,Fe, indicating the proportions of Mo, S transported into the upper part of plant tissues was higher than that of Fe, and the corresponding value of B was higher than that observed for S, the corresponding value of Mg was higher than that of Fe and Mn. Under normal-N application, the elevation of atmospheric CO2 increased the transport coefficients of SMg,Fe, SMg,Mn and SS,B, but decreased the transport coefficients of SCa, Mg, SFe,Mo and SS,Fe indicating the proportions of Fe, Mn and Ca transported into the upper part of plant tissues was higher than that of Mg; the corresponding value of B was higher than that observed for S, the corresponding value of Fe was higher than that of Mo, and the corresponding value of S was higher than that of Fe.

Long-term fertilization, but not warming, shifts rates of ectomycorrhizal nutrient cycling in Arctic tussock tundra.

NASA Astrophysics Data System (ADS)

Dunleavy, H.; Mack, M. C.

2017-12-01

The role of ectomycorrhizae (ECM) in Arctic nutrient cycling may be changing as temperature, nutrient availability, and ECM shrub abundance and size increase. A shift in ECM function has been proposed as a possible mechanism for shrub expansion. While several studies demonstrate a higher abundance of ECM as well as community compositional shifts in response to long-term experimental warming and fertilization, direct measurements of functional responses are missing. To understand the potential role of ECM in soil biogeochemical processes of the changing Arctic, we investigated the functional response of ECM to 30 years of summer warming and increased nutrient availability by measuring potential activities of extracellular enzymes associated with nitrogen (N) and phosphorous (P) acquisition on ECM root tips. We hypothesize ECM enzyme activities will be higher with warmer temperatures. Conversely, fertilization will lower ECM enzyme activities as N and P become less limiting to host plants. Preliminary results strongly support our latter hypothesis, but not the first. Warming decreased hydrolytic P-associated and labile N-associated enzyme activities on individual root tips (pmol/min/mm2 root tip) by 30% and 83%, respectively. However, warming increased ECM abundance and did not alter community-level activities (pmol/min/cm3 soil). Fertilization decreased hydrolytic and oxidative enzymatic activities on individual root tips by 34 to 80% as well as on a community level by 67 to 93%, even though ECM shrubs were almost monodominant. The combined effect of warming and fertilization decreased labile N-associated enzyme activity by 82%, but had little effect on oxidative and other hydrolytic enzyme activities. Although both warming and fertilization decreased root tip activities, reflecting a potential reduction in plant allocation to mycorrhizal nutrient acquisition, only fertilization lowered rates of ECM nutrient cycling. The indirect relationship between ECM abundance and individual root tip activity highlights the importance of measuring ECM function to assess the role of this symbiosis in nutrient cycling.

Renal formulas pretreated with medications alters the nutrient profile

PubMed Central

Oladitan, Leah; Carlson, Susan; Hamilton-Reeves, Jill M.

2015-01-01

Background Pretreating renal formulas with medications to lower the potassium and phosphorus content is common in clinical practice; however, the effect of this treatment on other nutrients is relatively unstudied. We examine whether nutrient composition is affected by pretreating renal formulas with sodium polystyrene sulfonate (SPS) suspension and sevelamer carbonate. Methods Fixed medication doses and treatment times were utilized to determine changes in the nutrient composition of Suplena® and Similac® PM 60/40. The effect of simultaneously adding both medications (co-administration) to the formula on the nutrient composition of Suplena® was also evaluated. Results Pretreatment of Suplena® with SPS reduced the concentrations of calcium (11–38 %), copper (3–11 %), manganese (3–16 %), phosphorus (0–7 %), potassium (6–34 %), and zinc (5–20 %) and increased those of iron (9–34 %), sodium (89–260 %), and sulfur (19–45 %) and the pH (0.20–0.50 units). Pretreatment of Similac® PM 60/40 with SPS reduced the concentrations of calcium (8–29 %), copper (5–19 %), magnesium (3–26 %), and potassium (33–63 %) and increased those of iron (13–87 %) and sodium (86–247 %) and the pH (0.40–0.81 units). Pretreatment of both formulas with the SPS suspension led to significant increases in the aluminum concentration in both formulas (507–3957 %). No differences in potassium concentration were observed between treatment times. Unexpectedly, the levels of neither phosphorus nor potassium were effectively reduced in Suplena® pretreated with sevelamer carbonate alone or when co-administered with SPS. Conclusions Pretreating formula with medications alters nutrients other than the intended target(s). Future studies should be aimed at predicting the loss of these nutrients or identifying alternative methods for managing serum potassium and phosphorus levels in formula-fed infants. The safety of pretreating formula with SPS suspension should also be examined. PMID:25930981

Effects of productivity, consumers, competitors, and El Nino events on food chain patterns in a rocky intertidal community

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wootton, J.T.; Pfister, C.A.; Paine, R.T.

We experimentally manipulated nutrient input to a rocky intertidal community, using nutrient-diffusing flowerpots, to determine (i) whether nutrients limited intertidal productivity, (ii) how a large-scale oceanographic disturbance (an El Nino event) affected patterns of nutrient limitation, (iii) the relative impacts of molluscan grazers and nutrient limitation, and (iv) if responses to experimental nutrient addition among trophic levels were more consistent with prey-dependent or ratio-dependent food chain models. Nutrients measurably increased the abundance of micrograzers (amphipods and chironomid larvae), but not algal biomass, during the summer of an El Nino years and during the autumn of an El Nino year. Addingmore » nutrients did not affect food chain stability as assessed by temporal variation in algal biomass and micrograzer abundance. Large molluscan grazers caused large reductions in micrograzers and smaller reductions in algae, indicating consistent consumer effects. The results demonstrate that in this intertidal community, nutrient limitation can occur under conditions of nutrient stress, that top-down grazing effects are typically stronger than bottom-up nutrient effects, and that prey-dependent models are more appropriate than ratio-dependent models. 40 refs., 1 fig., 1 tab.« less

Nutrition inequities in Canada.

PubMed

Tarasuk, Valerie; Fitzpatrick, Sandra; Ward, Heather

2010-04-01

In Canada, increased morbidity and shorter life expectancy have been found among those with lower incomes and lower levels of education, but there has been little examination of socioeconomic variation in food and nutrient intake. Using data from the 2004 Canadian Community Health Survey, we examined the relationship between household income and education level and adults' and children's intakes of energy, fibre, micronutrients, and number of servings consumed of food groups from Canada's Food Guide. To explore the public health significance of observed associations, we estimated the prevalence of inadequacy for selected nutrients for adults, stratifying by household income, education level, and sex. We found that a higher household income adequacy and (or) higher levels of education were associated with increased consumption of milk and alternatives, and vegetables and fruit, and significantly higher vitamin, mineral, and fibre intakes among both adults and children. The prevalence of inadequate nutrient intakes among adults was higher among adults with the lowest level of income adequacy or educational attainment, compared with others. Our results suggest that the nutritional quality of Canadians' food intakes is, in part, a function of their social position. The impact of policy and program interventions needs to be examined across socioeconomic strata to ensure that actions reduce rather than exacerbate nutrition inequities.

Ambient and elevated carbon dioxide on growth, physiological and nutrient uptake parameters of perennial leguminous cover crops under low light intensities

USDA-ARS?s Scientific Manuscript database

Adaptability and optimum growth of cover crops in plantation crops is affected by the inherent nature of the cover crop species and the light intensity at canopy levels. Globally concentrations of atmospheric CO2 are increasing and this creates higher photosynthesis and nutrient demand by crops as l...

Performance traits and metabolic responses in goats (Capra hircus) supplemented with inorganic trivalent chromium.

PubMed

Haldar, Sudipto; Mondal, Souvik; Samanta, Saikat; Ghosh, Tapan Kumar

2009-11-01

The effects of supplemental chromium (Cr) as chromic chloride hexahydrate in incremental dose levels (0, 0.5, 1.0, and 1.5 mg/day for 240 days) on metabolism of nutrients and trace elements were determined in dwarf Bengal goats (Capra hircus, castrated males, average age 3 months, n = 24, initial mean body weight 6.4 +/- 0.22 kg). Live weight increased linearly (p < 0.05) with the level of supplemental Cr. Organic matter and crude protein digestibility, intake of total digestible nutrients, and retention of N (g/g N intake) increased (p < 0.05) in a dose-dependent linear manner. Serum cholesterol and tryacylglycerol concentrations changed inversely with the dose of supplemental Cr (p < 0.01). Supplemental Cr positively influenced retention of copper and iron (p < 0.05) causing linear increase (p < 0.01) in their serum concentrations. It was concluded that Cr supplementation may improve utilization of nutrients including the trace elements and may also elicit a hypolidemic effect in goats. However, further study with regards to optimization of dose is warranted.

Eutrophication processes in the Gulf of Eilat (Aqaba), Red-Sea, and their effects on the coral reef ecosystem

NASA Astrophysics Data System (ADS)

Erez, J.; Iluz, D.; Zakai, D.; Silverman, J.; Lazar, B.

2003-04-01

In the past few years (since 1998) an on going eutrophication process has been observed in the Northern Gulf of Eilat. Nutrient levels have increased both in the deep and in the coastal waters. In parallel, the phytoplankton productivity in the open sea has increased by a factor of 3 from 100 to 300 gCm-2y-1. The main source of these nutrients is caged fish farms moored near the North Beach, which over the past 5 years have released more then 300 tons N annually. Surface circulation transports part of the nutrient-algae rich surface water along the Israeli coast, where they have been detected during the stratified period near the coral reef in the Nature Reserve. The bulk of the nutrients released from the fish cages are taken up by phytoplankton and increase the productivity of the pelagic ecosystem. Phytoplankton sinking and zooplankton grazing transport these nutrients to the deep water, below the thermocline where we observed a 50% increase in nitrate and phosphate concentrations relative to the previous decade. During the winter, vertical mixing brings these nutrients to the photic zone where massive blooms of benthic algae are observed in the coastal zone. These blooms are often associated with high coral mortality and have reduced live coral cover by 50% in the winter of 2000. Calcification rates of the reef ecosystem have decreased by a factor of 3--4 compared to earlier measurements in 1989--1991 while the photosynthesis to respiration ratio have increased from 1.0 to values higher then 1.5. These observations demonstrate the detrimental effects of anthropogenic nutrient enrichment on coral reefs.

Changes in nutrient dynamics of midcontinent greater white-fronted geese during spring migration

USGS Publications Warehouse

Pearse, Aaron T.; Alisauskas, Ray T.; Krapu, Gary L.; Cox, Robert R.

2011-01-01

Waterfowl and other migratory birds commonly store nutrients at traditional staging areas during spring for later use during migration and reproduction. We investigated nutrient-storage dynamics in the midcontinent population of greater white-fronted geese (Anser albifrons; hereafter white-fronted geese) at spring staging sites in the Rainwater Basin of Nebraska during February-April and in southern Saskatchewan during April-May, 1998 and 1999. In Nebraska, lipid content of white-fronted geese did not increase, and protein content changed little over time for most age and sex categories. In Saskatchewan, lipids increased 11.4 g/day (SE = 1.7) and protein content increased 1.6 g/day (SE = 0.6) in the sample of adult geese collected over a 3-week period. A study conducted during 1979-1980 in the Rainwater Basin reported that white-fronted geese gained 8.8-17.7 g of lipids per day during spring, differing greatly from our results 2 decades later. In addition, lipid levels were less in the 1990s compared to spring 1980 for adult geese nearing departure from staging sites in Saskatchewan. This shift in where geese acquired nutrient stores from Nebraska to more northern staging sites coincided with a decrease in availability of waste corn in Nebraska, their primary food source while staging at that stopover site, and an increase in cultivation of high-energy pulse crops in Saskatchewan. White-fronted geese exhibited flexibility in nutrient dynamics during spring migration, likely in response to landscape-level variation in food availability caused by changes in agricultural trends and practices. Maintaining a wide distribution of wetlands in the Great Plains may allow springstaging waterfowl to disperse across the region and facilitate access to high-energy foods over a larger cropland base.

Nutrient removal and biogas upgrading by integrating freshwater algae cultivation with piggery anaerobic digestate liquid treatment.

PubMed

Xu, Jie; Zhao, Yongjun; Zhao, Guohua; Zhang, Hui

2015-08-01

An integrated approach that combined freshwater microalgae Scenedesmus obliquus (FACHB-31) cultivation with piggery anaerobic digestate liquid treatment was investigated in this study. The characteristics of algal growth, biogas production, and nutrient removal were examined using photobioreactor bags (PBRbs) to cultivate S. obliquus (FACHB-31) in digestate with various digestate dilutions (the concentration levels of 3200, 2200, 1600, 1200, 800, and 400 mg L(-1) chemical oxygen demand (COD)) during 7-day period. The effects of the level of pollutants on nutrient removal efficiency and CO2 removal process were investigated to select the optimum system for effectively upgrade biogas and simultaneously reduce the nutrient content in digestate. The treatment performance displayed that average removal rates of COD, total nitrogen (TN), total phosphorous (TP), and CO2 were 61.58-75.29, 58.39-74.63, 70.09-88.79, and 54.26-73.81 %, respectively. All the strains grew well under any the dilution treatments. With increased initial nutrient concentration to a certain range, the CO4 content (v/v) of raw biogas increased. Differences in the biogas enrichment of S. obliquus (FACHB-31) in all treatments mainly resulted from variations in biomass productivity and CO2 uptake. Notably, the diluted digestate sample of 1600 mg L(-1) COD provided an optimal nutrient concentration for S. obliquus (FACHB-31) cultivation, where the advantageous nutrient and CO2 removals, as well as the highest productivities of biomass and biogas upgrading, were revealed. Results showed that microalgal biomass production offered real opportunities to address issues such as CO2 sequestration, wastewater treatment, and biogas production.

Sex-related differences in photoinhibition, photo-oxidative stress and photoprotection in stinging nettle (Urtica dioica L.) exposed to drought and nutrient deficiency.

PubMed

Simancas, Bárbara; Juvany, Marta; Cotado, Alba; Munné-Bosch, Sergi

2016-03-01

Dimorphic plant species can show distinct nutrient needs due to sex-related differences in nutrient allocation to reproductive structures, which can potentially affect their sensitivity to photoinhibition and photo-oxidative stress. Here, we investigated sex-related differences in the extent of photo-oxidative stress in male and female individuals of U. dioica exposed to a combination of severe drought and nutrient starvation. Male and female individuals of U. dioica subject to severe drought stress were exposed to various levels of nutrient availability. First, a set of plants grown under field conditions and exposed to summer drought was used to test the effects of nutrient supply (given as NPK fertilizer). Secondly, the effects of various phosphate concentrations in the nutrient solution were tested in drought-stressed potted plants. The Fv/Fm ratio (maximum efficiency of PSII photochemistry), photoprotection capacity (levels of carotenoids, including the xanthophyll cycle, and vitamins C and E), and the extent of lipid peroxidation (hydroperoxide levels) were measured. Results showed that an application of the NPK fertilizer to the soil had a positive effect on drought-stressed plants, reducing the extent of lipid peroxidation in both males and females. P deficiency led to residual photoinhibition, as indicated by significant reductions in the Fv/Fm ratio, and enhanced lipid peroxidation in females, but not in males. We conclude that (i) increased nutrient availability in the soil can alleviate photo-oxidative stress in drought-stressed U. dioica plants, and (ii) U. dioica plants show sexual secondary dimorphism in terms of photoinhibition and photo-oxidative stress, but this is only apparent when stress infringed on plants is very severe. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of soil nutrient heterogeneity on intraspecific competition in the invasive, clonal plant Alternanthera philoxeroides.

PubMed

Zhou, Jian; Dong, Bi-Cheng; Alpert, Peter; Li, Hong-Li; Zhang, Ming-Xiang; Lei, Guang-Chun; Yu, Fei-Hai

2012-03-01

Fine-scale, spatial heterogeneity in soil nutrient availability can increase the growth of individual plants, the productivity of plant communities and interspecific competition. If this is due to the ability of plants to concentrate their roots where nutrient levels are high, then nutrient heterogeneity should have little effect on intraspecific competition, especially when there are no genotypic differences between individuals in root plasticity. We tested this hypothesis in a widespread, clonal species in which individual plants are known to respond to nutrient heterogeneity. Plants derived from a single clone of Alternanthera philoxeroides were grown in the greenhouse at low or high density (four or 16 plants per 27·5 × 27·5-cm container) with homogeneous or heterogeneous availability of soil nutrients, keeping total nutrient availability per container constant. After 9 weeks, measurements of size, dry mass and morphology were taken. Plants grew more in the heterogeneous than in the homogeneous treatment, showing that heterogeneity promoted performance; they grew less in the high- than in the low-density treatment, showing that plants competed. There was no interactive effect of nutrient heterogeneity and plant density, supporting the hypothesis that heterogeneity does not affect intraspecific competition in the absence of genotypic differences in plasticity. Treatments did not affect morphological characteristics such as specific leaf area or root/shoot ratio. Results indicate that fine-scale, spatial heterogeneity in the availability of soil nutrients does not increase competition when plants are genetically identical, consistent with the suggestion that effects of heterogeneity on competition depend upon differences in plasticity between individuals. Heterogeneity is only likely to increase the spread of monoclonal, invasive populations such as that of A. philoxeroides in China.

The FOX transcription factor Hcm1 regulates oxidative metabolism in response to early nutrient limitation in yeast. Role of Snf1 and Tor1/Sch9 kinases.

PubMed

Rodríguez-Colman, María José; Sorolla, M Alba; Vall-Llaura, Núria; Tamarit, Jordi; Ros, Joaquim; Cabiscol, Elisa

2013-08-01

Within Saccharomyces cerevisiae, Hcm1is a member of the forkhead transcription factor family with a role in chromosome organization. Our group recently described its involvement in mitochondrial biogenesis and stress resistance, and reports here that Hcm1 played a role in adaptation to respiratory metabolism when glucose or nitrogen was decreased. Regulation of Hcm1 activity occurs in at least three ways: i) protein quantity, ii) subcellular localization, and iii) transcriptional activity. Transcriptional activity was measured using a reporter gene fused to a promoter that contains a binding site for Hcm1. We also analyzed the levels of several genes whose expression is known to be regulated by Hcm1 levels and the role of the main kinases known to respond to nutrients. Lack of sucrose-nonfermenting (Snf1) kinase increases cytoplasmic localization of Hcm1, whereas Δtor1 cells showed a mild increase in nuclear Hcm1. In vitro experiments showed that Snf1 clearly phosphorylates Hcm1 while Sch9 exerts a milder phosphorylation. Although in vitroTor1 does not directly phosphorylate Hcm1, in vivo rapamycin treatment increases nuclear Hcm1. We conclude that Hcm1 participates in the adaptation of cells from fermentation to respiratory metabolism during nutrient scarcity. According to our hypothesis, when nutrient levels decrease, Snf1 phosphorylates Hcm1. This results in a shift from the cytoplasm to the nucleus and increased transcriptional activity of genes involved in respiration, use of alternative energy sources, NAD synthesis and oxidative stress resistance. Copyright © 2013 Elsevier B.V. All rights reserved.

The Nutrient Balance Concept: A New Quality Metric for Composite Meals and Diets

PubMed Central

Fern, Edward B; Watzke, Heribert; Barclay, Denis V.; Roulin, Anne; Drewnowski, Adam

2015-01-01

Background Combinations of foods that provide suitable levels of nutrients and energy are required for optimum health. Currently, however, it is difficult to define numerically what are ‘suitable levels’. Objective To develop new metrics based on energy considerations—the Nutrient Balance Concept (NBC)—for assessing overall nutrition quality when combining foods and meals. Method The NBC was developed using the USDA Food Composition Database (Release 27) and illustrated with their MyPlate 7-day sample menus for a 2000 calorie food pattern. The NBC concept is centered on three specific metrics for a given food, meal or diet—a Qualifying Index (QI), a Disqualifying Index (DI) and a Nutrient Balance (NB). The QI and DI were determined, respectively, from the content of 27 essential nutrients and 6 nutrients associated with negative health outcomes. The third metric, the Nutrient Balance (NB), was derived from the Qualifying Index (QI) and provided key information on the relative content of qualifying nutrients in the food. Because the Qualifying and Disqualifying Indices (QI and DI) were standardized to energy content, both become constants for a given food/meal/diet and a particular consumer age group, making it possible to develop algorithms for predicting nutrition quality when combining different foods. Results Combining different foods into composite meals and daily diets led to improved nutrition quality as seen by QI values closer to unity (indicating nutrient density was better equilibrated with energy density), DI values below 1.0 (denoting an acceptable level of consumption of disqualifying nutrients) and increased NB values (signifying complementarity of foods and better provision of qualifying nutrients). Conclusion The Nutrient Balance Concept (NBC) represents a new approach to nutrient profiling and the first step in the progression from the nutrient evaluation of individual foods to that of multiple foods in the context of meals and total diets. PMID:26176770

Chemical characterization of biochar and assessment of the nutrient dynamics by means of preliminary plant growth tests.

PubMed

Prasad, Munoo; Tzortzakis, Nikos; McDaniel, Nicola

2018-06-15

Biochar can be produced from several organic sources with varying nutrients and metal concentrations. Four commercial grade biochars were evaluated as peat substitute. Biochars were characterised for plant nutrients and for biological stability. The results showed that there were negligible quantities of N and P and generally high levels of K and high biological stability. When these materials were mixed with peat at 10, 25 and 50% and nutrients were added to bring them to the same level of nutrients as in fertilized peat, it was found that biochar mixtures considerably reduced the levels of calcium chloride/DTPA (CAT) extractable N (including nitrate), P, and electrical conductivity- greater extent with higher rates of biochar addition except for K. The pH and K levels were increased with biochar addition. The drop in EC has important implications regarding the use of other materials used to dilute peat, for example, composted green waste, the rate of dilution is limited due to high EC and biochar addition gives the potential for higher peat dilution of these materials. Nitrate and phosphorus are very vulnerable to leaching of these nutrients in the environment in peat substrates and the binding of these by biochar has implication for leaching and nutrient application strategy. Root development using Cress test and tomato plant height and biomass using containers, were in some cases better than peat indicating that biochar could be used to dilute peat e.g. for seedling production where root development and rapid growth are very important. Application of biochars resulted in a marked reduction of N (and P) in the plant. There were significant correlation between CAT extractable N and P and corresponding plant concentration, indicating the standard growing media test, CAT, would be suitable for assessing the nutrient status of peat biochar mixes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fish extinctions alter nutrient recycling in tropical freshwaters.

PubMed

McIntyre, Peter B; Jones, Laura E; Flecker, Alexander S; Vanni, Michael J

2007-03-13

There is increasing evidence that species extinctions jeopardize the functioning of ecosystems. Overfishing and other human influences are reducing the diversity and abundance of fish worldwide, but the ecosystem-level consequences of these changes have not been assessed quantitatively. Recycling of nutrients is one important ecosystem process that is directly influenced by fish. Fish species vary widely in the rates at which they excrete nitrogen and phosphorus; thus, altering fish communities could affect nutrient recycling. Here, we use extensive field data on nutrient recycling rates and population sizes of fish species in a Neotropical river and Lake Tanganyika, Africa, to evaluate the effects of simulated extinctions on nutrient recycling. In both of these species-rich ecosystems, recycling was dominated by relatively few species, but contributions of individual species differed between nitrogen and phosphorus. Alternative extinction scenarios produced widely divergent patterns. Loss of the species targeted by fishermen led to faster declines in nutrient recycling than extinctions in order of rarity, body size, or trophic position. However, when surviving species were allowed to increase after extinctions, these compensatory responses had strong moderating effects even after losing many species. Our results underscore the complexity of predicting the consequences of extinctions from species-rich animal communities. Nevertheless, the importance of exploited species in nutrient recycling suggests that overfishing could have particularly detrimental effects on ecosystem functioning.

Nitrogen and phosphorus uptake rates of different species from a coral reef community after a nutrient pulse

PubMed Central

den Haan, Joost; Huisman, Jef; Brocke, Hannah J.; Goehlich, Henry; Latijnhouwers, Kelly R. W.; van Heeringen, Seth; Honcoop, Saskia A. S.; Bleyenberg, Tanja E.; Schouten, Stefan; Cerli, Chiara; Hoitinga, Leo; Vermeij, Mark J. A.; Visser, Petra M.

2016-01-01

Terrestrial runoff after heavy rainfall can increase nutrient concentrations in waters overlying coral reefs that otherwise experience low nutrient levels. Field measurements during a runoff event showed a sharp increase in nitrate (75-fold), phosphate (31-fold) and ammonium concentrations (3-fold) in waters overlying a fringing reef at the island of Curaçao (Southern Caribbean). To understand how benthic reef organisms make use of such nutrient pulses, we determined ammonium, nitrate and phosphate uptake rates for one abundant coral species, turf algae, six macroalgal and two benthic cyanobacterial species in a series of laboratory experiments. Nutrient uptake rates differed among benthic functional groups. The filamentous macroalga Cladophora spp., turf algae and the benthic cyanobacterium Lyngbya majuscula had the highest uptake rates per unit biomass, whereas the coral Madracis mirabilis had the lowest. Combining nutrient uptake rates with the standing biomass of each functional group on the reef, we estimated that the ammonium and phosphate delivered during runoff events is mostly taken up by turf algae and the two macroalgae Lobophora variegata and Dictyota pulchella. Our results support the often proposed, but rarely tested, assumption that turf algae and opportunistic macroalgae primarily benefit from episodic inputs of nutrients to coral reefs. PMID:27353576

Nitrogen and phosphorus uptake rates of different species from a coral reef community after a nutrient pulse

NASA Astrophysics Data System (ADS)

den Haan, Joost; Huisman, Jef; Brocke, Hannah J.; Goehlich, Henry; Latijnhouwers, Kelly R. W.; van Heeringen, Seth; Honcoop, Saskia A. S.; Bleyenberg, Tanja E.; Schouten, Stefan; Cerli, Chiara; Hoitinga, Leo; Vermeij, Mark J. A.; Visser, Petra M.

2016-06-01

Terrestrial runoff after heavy rainfall can increase nutrient concentrations in waters overlying coral reefs that otherwise experience low nutrient levels. Field measurements during a runoff event showed a sharp increase in nitrate (75-fold), phosphate (31-fold) and ammonium concentrations (3-fold) in waters overlying a fringing reef at the island of Curaçao (Southern Caribbean). To understand how benthic reef organisms make use of such nutrient pulses, we determined ammonium, nitrate and phosphate uptake rates for one abundant coral species, turf algae, six macroalgal and two benthic cyanobacterial species in a series of laboratory experiments. Nutrient uptake rates differed among benthic functional groups. The filamentous macroalga Cladophora spp., turf algae and the benthic cyanobacterium Lyngbya majuscula had the highest uptake rates per unit biomass, whereas the coral Madracis mirabilis had the lowest. Combining nutrient uptake rates with the standing biomass of each functional group on the reef, we estimated that the ammonium and phosphate delivered during runoff events is mostly taken up by turf algae and the two macroalgae Lobophora variegata and Dictyota pulchella. Our results support the often proposed, but rarely tested, assumption that turf algae and opportunistic macroalgae primarily benefit from episodic inputs of nutrients to coral reefs.

Nitrogen and phosphorus uptake rates of different species from a coral reef community after a nutrient pulse.

PubMed

den Haan, Joost; Huisman, Jef; Brocke, Hannah J; Goehlich, Henry; Latijnhouwers, Kelly R W; van Heeringen, Seth; Honcoop, Saskia A S; Bleyenberg, Tanja E; Schouten, Stefan; Cerli, Chiara; Hoitinga, Leo; Vermeij, Mark J A; Visser, Petra M

2016-06-29

Terrestrial runoff after heavy rainfall can increase nutrient concentrations in waters overlying coral reefs that otherwise experience low nutrient levels. Field measurements during a runoff event showed a sharp increase in nitrate (75-fold), phosphate (31-fold) and ammonium concentrations (3-fold) in waters overlying a fringing reef at the island of Curaçao (Southern Caribbean). To understand how benthic reef organisms make use of such nutrient pulses, we determined ammonium, nitrate and phosphate uptake rates for one abundant coral species, turf algae, six macroalgal and two benthic cyanobacterial species in a series of laboratory experiments. Nutrient uptake rates differed among benthic functional groups. The filamentous macroalga Cladophora spp., turf algae and the benthic cyanobacterium Lyngbya majuscula had the highest uptake rates per unit biomass, whereas the coral Madracis mirabilis had the lowest. Combining nutrient uptake rates with the standing biomass of each functional group on the reef, we estimated that the ammonium and phosphate delivered during runoff events is mostly taken up by turf algae and the two macroalgae Lobophora variegata and Dictyota pulchella. Our results support the often proposed, but rarely tested, assumption that turf algae and opportunistic macroalgae primarily benefit from episodic inputs of nutrients to coral reefs.

Soil nutrient availability and reproductive effort drive patterns in nutrient resorption in Pentachlethra macroloba

Treesearch

K. L. Tully; Tana Wood; A. M. Schwantes; D. Lawrence

2013-01-01

The removal of nutrients from senescing tissues, nutrient resorption, is a key strategy for conserving nutrients in plants. However, our understanding of what drives patterns of nutrient resorption in tropical trees is limited. We examined the effects of nutrient sources (stand-level and tree-level soil fertility) and sinks (reproductive effort) on nitrogen (N) and...

Testing for thresholds of ecosystem collapse in seagrass meadows.

PubMed

Connell, Sean D; Fernandes, Milena; Burnell, Owen W; Doubleday, Zoë A; Griffin, Kingsley J; Irving, Andrew D; Leung, Jonathan Y S; Owen, Samuel; Russell, Bayden D; Falkenberg, Laura J

2017-10-01

Although the public desire for healthy environments is clear-cut, the science and management of ecosystem health has not been as simple. Ecological systems can be dynamic and can shift abruptly from one ecosystem state to another. Such unpredictable shifts result when ecological thresholds are crossed; that is, small cumulative increases in an environmental stressor drive a much greater change than could be predicted from linear effects, suggesting an unforeseen tipping point is crossed. In coastal waters, broad-scale seagrass loss often occurs as a sudden event associated with human-driven nutrient enrichment (eutrophication). We tested whether the response of seagrass ecosystems to coastal nutrient enrichment is subject to a threshold effect. We exposed seagrass plots to different levels of nutrient enrichment (dissolved inorganic nitrogen) for 10 months and measured net production. Seagrass response exhibited a threshold pattern when nutrient enrichment exceeded moderate levels: there was an abrupt and large shift from positive to negative net leaf production (from approximately 0.04 leaf production to 0.02 leaf loss per day). Epiphyte load also increased as nutrient enrichment increased, which may have driven the shift in leaf production. Inadvertently crossing such thresholds, as can occur through ineffective management of land-derived inputs such as wastewater and stormwater runoff along urbanized coasts, may account for the widely observed sudden loss of seagrass meadows. Identification of tipping points may improve not only adaptive-management monitoring that seeks to avoid threshold effects, but also restoration approaches in systems that have crossed them. © 2017 Society for Conservation Biology.

Effects of apple branch biochar on soil C mineralization and nutrient cycling under two levels of N.

PubMed

Li, Shuailin; Liang, Chutao; Shangguan, Zhouping

2017-12-31

The incorporation of biochar into soil has been proposed as a strategy for enhancing soil fertility and crop productivity. However, there is limited information regarding the responses of soil respiration and the C, N and P cycles to the addition of apple branch biochar at different rates to soil with different levels of N. A 108-day incubation experiment was conducted to investigate the effects of the rate of biochar addition (0, 1, 2 and 4% by mass) on soil respiration and nutrients and the activities of enzymes involved in C, N and P cycling under two levels of N. Our results showed that the application of apple branch biochar at rates of 2% and 4% increased the C-mineralization rate, while biochar amendment at 1% decreased the C-mineralization rate, regardless of the N level. The soil organic C and microbial biomass C and P contents increased as the rate of biochar addition was increased to 2%. The biochar had negative effects on β-glucosidase, N-acetyl-β-glucosaminidase and urease activity in N-poor soil but exerted a positive effect on all of these factors in N-rich soil. Alkaline phosphatase activity increased with an increase in the rate of biochar addition, but the available P contents after all biochar addition treatments were lower than those obtained in the treatments without biochar. Biochar application at rates of 2% and 4% reduced the soil nitrate content, particularly in N-rich soil. Thus, apple branch biochar has the potential to sequester C and improve soil fertility, but the responses of soil C mineralization and nutrient cycling depend on the rate of addition and soil N levels. Copyright © 2017 Elsevier B.V. All rights reserved.

Nutrient enrichment can increase the susceptibility of reef corals to bleaching

NASA Astrophysics Data System (ADS)

Wiedenmann, Jörg; D'Angelo, Cecilia; Smith, Edward G.; Hunt, Alan N.; Legiret, François-Eric; Postle, Anthony D.; Achterberg, Eric P.

2013-02-01

Mass coral bleaching, resulting from the breakdown of coral-algal symbiosis has been identified as the most severe threat to coral reef survival on a global scale. Regionally, nutrient enrichment of reef waters is often associated with a significant loss of coral cover and diversity. Recently, increased dissolved inorganic nitrogen concentrations have been linked to a reduction of the temperature threshold of coral bleaching, a phenomenon for which no mechanistic explanation is available. Here we show that increased levels of dissolved inorganic nitrogen in combination with limited phosphate concentrations result in an increased susceptibility of corals to temperature- and light-induced bleaching. Mass spectrometric analyses of the algal lipidome revealed a marked accumulation of sulpholipids under these conditions. Together with increased phosphatase activities, this change indicates that the imbalanced supply of dissolved inorganic nitrogen results in phosphate starvation of the symbiotic algae. Based on these findings we introduce a conceptual model that links unfavourable ratios of dissolved inorganic nutrients in the water column with established mechanisms of coral bleaching. Notably, this model improves the understanding of the detrimental effects of coastal nutrient enrichment on coral reefs, which is urgently required to support knowledge-based management strategies to mitigate the effects of climate change.

Community temporal variability increases with fluctuating resource availability

PubMed Central

Li, Wei; Stevens, M. Henry H.

2017-01-01

An increase in the quantity of available resources is known to affect temporal variability of aggregate community properties. However, it is unclear how might fluctuations in resource availability alter community-level temporal variability. Here we conduct a microcosm experiment with laboratory protist community subjected to manipulated resource pulses that vary in intensity, duration and time of supply, and examine the impact of fluctuating resource availability on temporal variability of the recipient community. The results showed that the temporal variation of total protist abundance increased with the magnitude of resource pulses, as protist community receiving infrequent resource pulses (i.e., high-magnitude nutrients per pulse) was relatively more unstable than community receiving multiple resource pulses (i.e., low-magnitude nutrients per pulse), although the same total amounts of nutrients were added to each community. Meanwhile, the timing effect of fluctuating resources did not significantly alter community temporal variability. Further analysis showed that fluctuating resource availability increased community temporal variability by increasing the degree of community-wide species synchrony and decreasing the stabilizing effects of dominant species. Hence, the importance of fluctuating resource availability in influencing community stability and the regulatory mechanisms merit more attention, especially when global ecosystems are experiencing high rates of anthropogenic nutrient inputs. PMID:28345592

Community temporal variability increases with fluctuating resource availability

NASA Astrophysics Data System (ADS)

Li, Wei; Stevens, M. Henry H.

2017-03-01

An increase in the quantity of available resources is known to affect temporal variability of aggregate community properties. However, it is unclear how might fluctuations in resource availability alter community-level temporal variability. Here we conduct a microcosm experiment with laboratory protist community subjected to manipulated resource pulses that vary in intensity, duration and time of supply, and examine the impact of fluctuating resource availability on temporal variability of the recipient community. The results showed that the temporal variation of total protist abundance increased with the magnitude of resource pulses, as protist community receiving infrequent resource pulses (i.e., high-magnitude nutrients per pulse) was relatively more unstable than community receiving multiple resource pulses (i.e., low-magnitude nutrients per pulse), although the same total amounts of nutrients were added to each community. Meanwhile, the timing effect of fluctuating resources did not significantly alter community temporal variability. Further analysis showed that fluctuating resource availability increased community temporal variability by increasing the degree of community-wide species synchrony and decreasing the stabilizing effects of dominant species. Hence, the importance of fluctuating resource availability in influencing community stability and the regulatory mechanisms merit more attention, especially when global ecosystems are experiencing high rates of anthropogenic nutrient inputs.

The effects and mechanisms of mitochondrial nutrient alpha-lipoic acid on improving age-associated mitochondrial and cognitive dysfunction: an overview.

PubMed

Liu, Jiankang

2008-01-01

We have identified a group of nutrients that can directly or indirectly protect mitochondria from oxidative damage and improve mitochondrial function and named them "mitochondrial nutrients". The direct protection includes preventing the generation of oxidants, scavenging free radicals or inhibiting oxidant reactivity, and elevating cofactors of defective mitochondrial enzymes with increased Michaelis-Menten constant to stimulate enzyme activity, and also protect enzymes from further oxidation, and the indirect protection includes repairing oxidative damage by enhancing antioxidant defense systems either through activation of phase 2 enzymes or through increase in mitochondrial biogenesis. In this review, we take alpha-lipoic acid (LA) as an example of mitochondrial nutrients by summarizing the protective effects and possible mechanisms of LA and its derivatives on age-associated cognitive and mitochondrial dysfunction of the brain. LA and its derivatives improve the age-associated decline of memory, improve mitochondrial structure and function, inhibit the age-associated increase of oxidative damage, elevate the levels of antioxidants, and restore the activity of key enzymes. In addition, co-administration of LA with other mitochondrial nutrients, such as acetyl-L: -carnitine and coenzyme Q10, appears more effective in improving cognitive dysfunction and reducing oxidative mitochondrial dysfunction. Therefore, administrating mitochondrial nutrients, such as LA and its derivatives in combination with other mitochondrial nutrients to aged people and patients suffering from neurodegenerative diseases, may be an effective strategy for improving mitochondrial and cognitive dysfunction.

Effect of mineral nutrients on cell growth and self-flocculation of Tolypothrix tenuis for the production of a biofertilizer.

PubMed

Silva, P G; Silva, H J

2007-02-01

The influence of mineral nutrients on the growth and self-flocculation of Tolypothrix tenuis was studied. The identification of possible limiting nutrients in the culture medium was performed by the biomass elemental composition approach. A factorial experimental design was used in order to estimate the contribution of macronutrients and micronutrients, as well as their interactions. Iron was identified to be limiting in the culture medium. The micronutrients influenced mainly cellular growth without effects on self-flocculation. Conversely, the self-flocculation capacity of the biomass increased at higher concentrations of macronutrients. The optimization of mineral nutrition of T. tenuis allowed a 73% increase in the final biomass level and 3.5 times higher flocculation rates.

A comparison of algal, macroinvertebrate, and fish assemblage indices for assessing low-level nutrient enrichment in wadeable Ozark streams

USGS Publications Warehouse

Justus, B.G.; Femmer, Suzanne R.; Davis, Jerri V.; Petersen, James C.; Wallace, J.E.

2010-01-01

All three biotic indices were negatively correlated to nutrient concentrations but the algal index had a higher correlation (rho = −0.89) than did the macroinvertebrate and fish indices (rho = −0.63 and −0.58, respectively). Biotic index scores were lowest and nutrient concentrations were highest for streams with basins having the highest poultry and cattle production. Because of the availability of litter for fertilizer and associated increases in grass and hay production, cattle feeding capacity increases with poultry production. Studies are needed that address the synergistic effect of poultry and cattle production on Ozark streams in high production areas before ecological risks can be adequately addressed.

Upregulation of growth signaling and nutrient transporters in cotyledons of early to mid-gestational nutrient restricted ewes

PubMed Central

Ma, Yan; Zhu, Mei J.; Uthlaut, Adam B.; Nijland, Mark J.; Nathanielsz, Peter W.; Hess, Bret W.; Ford, Stephen P.

2011-01-01

Multiparous ewes received 100% (control, C, n=13) or 50% (nutrient restricted, NR, n=14) of NRC dietary requirements from d28-d78 of gestation. On d78, 5 C and 6 NR ewes were necropsied. The remaining 8 C and 8 NR ewes were fed to 100% of NRC from d78-d135 and necropsied. Maternal blood was collected at both necropsies and at weekly intervals for assay of glucose, insulin and leptin. Fetal blood was collected at d78 and d135 necropsies for assay of glucose and lipids. Cotyledonary (COT) tissue was evaluated for protein and mRNA expression [fatty acid transporter (FATP)1, FATP4, CD36, glucose transporter (GLUT)1 and GLUT3], mRNA expression only [placenta fatty acid binding protein (FABPpm) and lipoprotein lipase (LPL)], or expression of phosphorylated and total protein forms [AMP kinase (AMPK)α, acetyl-CoA carboxylase (ACC), extracellular signal-regulated kinase (Erk)1/2, mammalian target of rapamycin (mTOR) and protein kinase B (Akt)]. On d78, but not d135, placental and fetal weights were reduced (P < 0.05) in NR vs. C ewes. Maternal circulating glucose, insulin and leptin levels were decreased in NR vs. C ewes on d78 (P < 0.05) but similar at d135. Fetal blood glucose and triglyceride levels were lower in NR vs. C ewes (P < 0.05) on d78, but similar on d135. On d78, GLUT1, FATP4, CD36 mRNA and protein expression levels, FABPpm mRNA level, and leptin protein level were all increased (P < 0.05) in COT of NR vs. C ewes. AMPK, ACC, and Erk1/2 activities were also increased (P < 0.05) in NR vs. C COT on d78. In contrast, only FATP4 was increased (P < 0.05) at both the mRNA and protein levels in COT of NR realimented vs. C ewes on d135. These data demonstrate placental adaptation to maternal NR through increasing nutrient transporter production and growth signaling activity. PMID:21292322

Effect of soil salinity and nutrient levels on the community structure of the root-associated bacteria of the facultative halophyte, Tamarix ramosissima, in southwestern United States.

PubMed

Taniguchi, Takeshi; Imada, Shogo; Acharya, Kumud; Iwanaga, Fumiko; Yamanaka, Norikazu

2015-01-01

Tamarix ramosissima is a tree species that is highly resistant to salt and drought. The Tamarix species survives in a broad range of environmental salt levels, and invades major river systems in southwestern United States. It may affect root-associated bacteria (RB) by increasing soil salts and nutrients. The effects of RB on host plants may vary even under saline conditions, and the relationship may be important for T. ramosissima. However, to the best of our knowledge, there have been no reports relating to T. ramosissima RB and its association with salinity and nutrient levels. In this study, we have examined this association and the effect of arbuscular mycorrhizal colonization of T. ramosissima on RB because a previous study has reported that colonization of arbuscular mycorrhizal fungi affected the rhizobacterial community (Marschner et al., 2001). T. ramosissima roots were collected from five locations with varying soil salinity and nutrient levels. RB community structures were examined by terminal restriction fragment (T-RF) length polymorphism, cloning, and sequencing analyses. The results suggest that RB richness, or the diversity of T. ramosissima, have significant negative relationships with electrical conductivity (EC), sodium concentration (Na), and the colonization of arbuscular mycorrhizal fungi, but have a significant positive relationship with phosphorus in the soil. However, at each T-RF level, positive correlations between the emergence of some T-RFs and EC or Na were observed. These results indicate that high salinity decreased the total number of RB species, but some saline-tolerant RB species multiplied with increasing salinity levels. The ordination scores of nonmetric multidimensional scale analysis of RB community composition show significant relationships with water content, calcium concentration, available phosphorus, and total nitrogen. These results indicate that the RB diversity and community composition of T. ramosissima are affected by soil salinity and nutrient levels. Sequence analysis detected one Bacteroidetes and eight Proteobacteria species. Most 16S rRNA gene sequences had high similarities with the bacteria isolated from saline conditions, indicating that at least a portion of the RB species observed in T. ramosissima was halotolerant.

Nutrient uptake and growth responses of Virginia pine to elevated atmospheric carbon dioxide. [Pisolithus tinctorius, Pinus virginiana Mill

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luxmoore, R.J.; O'Neill, E.G.; Ells, J.M.

One-year-old Virgina pine (Pinus virginiana Mill.) seedlings with native or Pisolithus tinctorius mycorrhizal associations were grown in pots with soil low in organic matter and in cation exchange capacity and were exposed to one of five atmospheric CO/sub 2/ levels in the range of 340 to 940 ..mu..L/L in open-top field chambers. The mean dry weight of the seedlings increased from 4.4 to 11.0 g/plant during the 122-d exposure period. Significant increases in dry weight and uptake of N, Ca, Al, Fe, Zn, and Sr occurred with CO/sub 2/ enrichment. Greater chemical uptake was associated with greater root weight. Specificmore » absorption rates for chemicals (uptake per gram of root per day) were generally not affected by CO/sub 2/ enrichment. The uptake of P and K was not increased with elevated CO/sub 2/, and these elements showed the greater nutrient-use efficiency (C gain per element uptake). The nutrient-use efficiency for N and Ca was not influenced by atmospheric CO/sub 2/ enrichment. Large increases in Zn uptake at high CO'' suggested an increase in rhizosphere acidification, which may have resulted from the release of protons from the roots, since it was estimated that cation uptake increasingly exceeded anion uptake with CO/sub 2/ enrichment. Potassium, P, and NO/sub 3//sup -/ concentrations in the pot leachate decreased with higher CO/sub 2/ levels, and a similar trend was found for Al and Mg. These results suggest that soil-plant systems may exhibit increased nutrient and chemical retention at elevated atmospheric CO/sub 2/.« less

Increasing Plant Based Foods or Dairy Foods Differentially Affects Nutrient Intakes: Dietary Scenarios Using NHANES 2007-2010.

PubMed

Cifelli, Christopher J; Houchins, Jenny A; Demmer, Elieke; Fulgoni, Victor L

2016-07-11

Diets rich in plant foods and lower in animal-based products have garnered increased attention among researchers, dietitians and health professionals in recent years for their potential to, not only improve health, but also to lessen the environmental impact. However, the potential effects of increasing plant-based foods at the expense of animal-based foods on macro- and micronutrient nutrient adequacy in the U.S. diet is unknown. In addition, dairy foods are consistently under consumed, thus the impact of increased dairy on nutrient adequacy is important to measure. Accordingly, the objective of this study was to use national survey data to model three different dietary scenarios to assess the effects of increasing plant-based foods or dairy foods on macronutrient intake and nutrient adequacy. Data from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 for persons two years and older (n = 17,387) were used in all the analyses. Comparisons were made of usual intake of macronutrients and shortfall nutrients of three dietary scenarios that increased intakes by 100%: (i) plant-based foods; (ii) protein-rich plant-based foods (i.e., legumes, nuts, seeds, soy); and (iii) milk, cheese and yogurt. Scenarios (i) and (ii) had commensurate reductions in animal product intake. In both children (2-18 years) and adults (≥19 years), the percent not meeting the Estimated Average Requirement (EAR) decreased for vitamin C, magnesium, vitamin E, folate and iron when plant-based foods were increased. However the percent not meeting the EAR increased for calcium, protein, vitamin A, and vitamin D in this scenario. Doubling protein-rich plant-based foods had no effect on nutrient intake because they were consumed in very low quantities in the baseline diet. The dairy model reduced the percent not meeting the EAR for calcium, vitamin A, vitamin D, magnesium, and protein, while sodium and saturated fat levels increased. Our modeling shows that increasing plant-based foods could lead to unintended dietary outcomes without simultaneous changes in the types and amounts of plant foods currently consumed. Increasing dairy foods, which are currently under-consumed, could assist in improving the intakes of many nutrients of concern.

Shifting the Arctic Carbon Balance: Effects of a Long-Term Fertilization Experiment and Anomalously Warm Temperatures on Net Ecosystem Exchange in the Alaskan Tundra

NASA Astrophysics Data System (ADS)

Ludwig, S.; Natali, S.; Rastetter, E. B.; Shaver, G. R.; Graham, L. M.; Jastrow, J. D.

2017-12-01

The arctic is warming at an accelerated rate relative to the globe. Among the predicted consequences of warming temperatures in the arctic are increased gross primary productivity (GPP), ecosystem respiration (ER), and nutrient availability. The net effect of these changes on the carbon (C) cycle and resulting C balance and feedback to climate change remain unclear. Historically the Arctic has been a C sink, but evidence from recent years suggests some regions in the Arctic are becoming C sources. To predict the role of the Arctic in global C cycling, the mechanisms affecting arctic C balances need to be better resolved. We measured net ecosystem exchange (NEE) in a long-term, multi-level, fertilization experiment at Toolik Lake, AK during an anomalously warm summer. We modeled NEE, ER, and GPP using a Bayesian network model. The best-fit model included Q10 temperature functions and linear fertilization functions for both ER and GPP. ER was more strongly affected by temperature and GPP was driven more by fertilization level. As a result, fertilization increased the C sink capacity, but only at moderate and low temperatures. At high temperatures (>28 °C) the NEE modeled for the highest level of fertilization was not significantly different from zero. In contrast, at ambient nutrient levels modeled NEE was significantly below zero (net uptake) until 35 °C, when it becomes neutral. Regardless of the level of fertilization, NEE never decreased with warming. Temperature in low ranges (5-15°C) had no net effect on NEE, whereas NEE began to increase exponentially with temperature after a threshold of 15°C until becoming a net source to the atmosphere at 37°C. Our results indicate that the C sink strength of tundra ecosystems can be increased with small increases in nutrient availability, but that large increase in nutrient availability can switch tundra ecosystems into C sources under warm conditions. Warming temperatures in tundra ecosystems will only decrease C sink strength, and the continued increase in days with anomalously high summer temperatures could lead to the Arctic tundra becoming a source of C and a positive feed back to climate change.

Salt exclusion and mycorrhizal symbiosis increase tolerance to NaCl and CaCl2 salinity in ‘Siam Queen’ basil

USDA-ARS?s Scientific Manuscript database

A study was conducted to evaluate the effects of salinity on growth and nutrient uptake in basil (Ocimum basilicum L.). Plants were fertilized with a complete nutrient solution and exposed to no, low, or moderate levels of salinity from NaCl or CaCl2. Plants in the control and moderate salinity tre...

Evaluation of commercially available enzymes, probiotics, or yeast on apparent total-tract nutrient digestion and growth in nursery and finishing pigs fed diets containing corn dried distillers grains with solubles

USDA-ARS?s Scientific Manuscript database

The ability of enzymes, direct fed microbials, or yeast to enhance nutrient utilization or growth performance in nursery or finishing pigs fed diets containing increased levels of corn fiber from dried distillers grains with solubles (DDGS) is largely unknown. Ten commercially available feed additiv...

Effects of feeding diets varying in energy and nutrient density to Hy-Line W-36 laying hens on production performance and economics.

PubMed

dePersio, S; Utterback, P L; Utterback, C W; Rochell, S J; O'Sullivan, N; Bregendahl, K; Arango, J; Parsons, C M; Koelkebeck, K W

2015-02-01

The objectives of this study were to evaluate the effects of feeding 5 different energy and nutrient dense diets to Hy-Line W-36 hens on long-term performance and economics. A total of 480 19 wk old Hy-Line W-36 Single Comb White Leghorn hens were weighed and randomly allocated to 6 replicate groups of 16 hens each (2 adjacent cages containing 8 hens per cage, 60.9×58.4 cm) per dietary treatment in a randomized complete block design. The hens were fed 5 treatment diets formulated to contain 85, 90, 95, 100, and 105% of the energy and nutrient recommendations stated in the 2009 Hy-Line Variety W-36 Commercial Management Guide. Production performance was measured for 52 wk from 19 to 70 wk age. Over the course of the trial, a significant increasing linear response to increasing energy and nutrient density was seen for hen-day egg production, egg weight, egg mass, feed efficiency, energy intake, and body weight (BW). Feed intake showed no significant linear level response to increasing energy and nutrient density except during the early production cycle. No consistent responses were noted for egg quality, percent yolk, and percent egg solids throughout the study. Significant linear responses due to energy and nutrient density were seen for egg income, feed cost, and income minus feed cost. In general, as energy and nutrient density increased, egg income and feed cost per hen increased, but income minus feed cost decreased. Overall, these results indicate that feeding Hy-Line W-36 hens increasing energy and nutrient-dense diets will increase egg production, egg weight, egg mass, feed efficiency, energy intake, BW, egg income, and feed cost, but decrease egg income minus feed cost. However, these benefits do not take effect in early production and seem to be most effective in later stages of the production cycle, perhaps "priming" the birds for better egg-production persistency with age. © 2015 Poultry Science Association Inc.

The effects of intraduodenal nutrient infusion on serum CCK, LES pressure, and gastroesophageal reflux.

PubMed

Lacy, B E; Carter, J; Weiss, J E; Crowell, M D

2011-07-01

Fats cause reflux symptoms in many patients and cholecystokinin (CCK) may play a role. This study was designed to evaluate the effects of intraduodenal nutrient infusion on serum CCK levels, lower esophageal sphincter (LES) pressure, and gastroesophageal reflux (GER). Twenty-four asymptomatic volunteers were studied. A Dent sleeve catheter assessed LES function while an impedance-pH catheter measured reflux events. Participants were randomized to fat (F), carbohydrate (C) or protein (P) infusion. Serum CCK and LES pressures were measured at baseline and after nutrient infusion. Baseline LES pressures and CCK levels were similar in all three groups. A significant linear decrease was found in LES pressure during F, but not C or P, infusion (P=0.004). A significant interaction effect was noted between the infusion groups and CCK levels (P=0.002). A significant linear increase was noted in CCK levels during F but not during C or P infusion (P=0.02). A significant inverse correlation was found between CCK levels and LES pressure (ρ=-0.43; P=0.04). Esophageal acid exposure was significantly increased in the F infusion group (median; interquartile range: 1.10%; 0.25-4.7%) compared to both the C (0.03%; 0.00-0.39%) and P infusion (0.03%; 0.00-0.39%) groups (P=0.04). Intraduodenal F infusion was associated with an increase in CCK levels, while P and C were not. LES pressure decreased significantly after fat infusion and reflux events were more frequent. Fat-induced CCK release is another mechanism that contributes to GER. © 2011 Blackwell Publishing Ltd.

Assessment of nutritional status in noninstitutionalized elderly.

PubMed

Powers, J S; Folk, M C; Burger, C; Wilson, P; Stocking, B J; Collins, J

1989-08-01

Aging may modify both the availability of and needs for certain nutrients. Our study was done to assess the contribution of age alone to micronutrient levels in older volunteers (aged 60 or more). One hundred two healthy elderly white subjects, 63 women and 39 men, carefully screened by history or chart review, were studied in the fasting state. All were noninstitutionalized without serious chronic or acute illness; their diets were nutritionally adequate, containing more than two thirds of the recommended dietary allowance (RDA) for all nutrients, and no subject was taking more than twice the RDA of fat-soluble vitamins. These subjects had higher levels of plasma and red blood cell carnitine, and vitamins A, E, and C. They had lower levels of albumin, transferrin, and zinc than younger laboratory reference subjects. Retinol-binding protein, serum and red blood cell folate, and copper levels were not different. With increasing age, levels of transferrin and vitamins C and E fell; all other measured micronutrient levels were similar. Albumin, vitamin C, and copper values were higher among elderly women, and plasma and red blood cell carnitine values and zinc levels were higher in elderly men. There was great variability in the micronutrient levels despite similar nutrient intakes.

Combined Effects of Dissolved Nutrients and Oxygen on Plant Litter Decomposition and Associated Fungal Communities.

PubMed

Gomes, Patrícia Pereira; Ferreira, Verónica; Tonin, Alan M; Medeiros, Adriana Oliveira; Júnior, José Francisco Gonçalves

2018-05-01

Aquatic ecosystems worldwide have been substantially altered by human activities, which often induce changes in multiple factors that can interact to produce complex effects. Here, we evaluated the combined effects of dissolved nutrients (nitrogen [N] and phosphorus [P]; three levels: concentration found in oligotrophic streams in the Cerrado biome, 10× and 100× enriched) and oxygen (O 2 ; three levels: hypoxic [4% O 2 ], depleted [55% O 2 ], and saturated [96% O 2 ]) on plant litter decomposition and associated fungal decomposers in laboratory microcosms simulating stream conditions under distinct scenarios of water quality deterioration. Senescent leaves of Maprounea guianensis were incubated for 10 days in an oligotrophic Cerrado stream to allow microbial colonization and subsequently incubated in microcosms for 21 days. Leaves lost 1.1-3.0% of their initial mass after 21 days, and this was not affected either by nutrients or oxygen levels. When considering simultaneous changes in nutrients and oxygen concentrations, simulating increased human pressure, fungal biomass accumulation, and sporulation rates were generally inhibited. Aquatic hyphomycete community structure was also affected by changes in nutrients and oxygen availability, with stronger effects found in hypoxic treatments than in depleted or saturated oxygen treatments. This study showed that the effects of simultaneous changes in the availability of dissolved nutrients and oxygen in aquatic environments can influence the activity and composition of fungal communities, although these effects were not translated into changes in litter decomposition rates.

Effects of different nitrogen levels on the leaf chlorophyll content nutrient concentration and nutrient uptake pattern of blackgram.

PubMed

Kulsum, M U; Baque, M A; Karim, M A

2007-01-15

This study was conducted to evaluate the performance of blackgram (Vigna mungo L) under various levels of nitrogen at the Agronomy Research Site of Bangabandhu Sheikh Mujibur Rahman Agricultural University during March to June 2002. Two varieties of blackgram--BARI mash 3 and BINA mash 1 and six levels of nitrogen viz. 0, 20, 40, 60, 80 and 100 kg N ha(-1) were the treatment variables. The experiment was laid out in a RCB Design with three replications. A best-fit positive linear relationship existed between leaf chlorophyll and leaf nitrogen content with different nitrogen levels. Unexpectedly the N, P and K accumulation in the two varieties was not affected significantly. However, there was an increasing tendency of total uptake of these elements in both the varieties. N, P and K uptake increased up to 60 kg N ha(-1) then decreased with the increasing nitrogen levels. Among the varieties BARI mash 3 showed better performance than BINA mash 1 for most of the parameters.

Nutrient production from dairy cattle manure and loading on arable land.

PubMed

Won, Seunggun; Shim, Soo-Min; You, Byung-Gu; Choi, Yoon-Seok; Ra, Changsix

2017-01-01

Along with increasing livestock products via intensive rearing, the accumulation of livestock manure has become a serious issue due to the fact that there is finite land for livestock manure recycling via composting. The nutrients from livestock manure accumulate on agricultural land and the excess disembogues into streams causing eutrophication. In order to systematically manage nutrient loading on agricultural land, quantifying the amount of nutrients according to their respective sources is very important. However, there is a lack of research concerning nutrient loss from livestock manure during composting or storage on farms. Therefore, in the present study we quantified the nutrients from dairy cattle manure that were imparted onto agricultural land. Through investigation of 41 dairy farms, weight reduction and volatile solids (VS), total nitrogen (TN), and total phosphorus (TP) changes of dairy cattle manure during the storage and composting periods were analyzed. In order to support the direct investigation and survey on site, the three cases of weight reduction during the storing and composting periods were developed according to i) experiment, ii) reference, and iii) theoretical changes in phosphorus content (ΔP = 0). The data revealed the nutrient loading coefficients (NLCs) of VS, TN, and TP on agricultural land were 1.48, 0.60, and 0.66, respectively. These values indicated that the loss of nitrogen and phosphorus was 40% and 34%, respectively, and that there was an increase of VS since bedding materials were mixed with excretion in the barn. As result of nutrient-footprint analyses, the amounts of TN and TP particularly entered on arable land have been overestimated if applying the nutrient amount in fresh manure. The NLCs obtained in this study may assist in the development of a database to assess the accurate level of manure nutrient loading on soil and facilitate systematic nutrient management.

Effects of selective breeding for high voluntary wheel-running behavior on femoral nutrient canal size and abundance in house mice.

PubMed

Schwartz, Nicolas L; Patel, Biren A; Garland, Theodore; Horner, Angela M

2018-05-31

Bone modeling and remodeling are aerobic processes that entail relatively high oxygen demands. Long bones receive oxygenated blood from nutrient arteries, epiphyseal-metaphyseal arteries, and periosteal arteries, with the nutrient artery supplying the bulk of total blood volume in mammals (~ 50-70%). Estimates of blood flow into these bones can be made from the dimensions of the nutrient canal, through which nutrient arteries pass. Unfortunately, measuring these canal dimensions non-invasively (i.e. without physical sectioning) is difficult, and thus researchers have relied on more readily visible skeletal proxies. Specifically, the size of the nutrient artery has been estimated from dimensions (e.g. minimum diameters) of the periosteal (external) opening of the nutrient canal. This approach has also been utilized by some comparative morphologists and paleontologists, as the opening of a nutrient canal is present long after the vascular soft tissue has degenerated. The literature on nutrient arteries and canals is sparse, with most studies consisting of anatomical descriptions from surgical proceedings, and only a few investigating the links between nutrient canal morphology and physiology or behavior. The primary objective of this study was to evaluate femur nutrient canal morphology in mice with known physiological and behavioral differences; specifically, mice from an artificial selection experiment for high voluntary wheel-running behavior. Mice from four replicate high runner (HR) lines are known to differ from four non-selected control (C) lines in both locomotor and metabolic activity, with HR mice having increased voluntary wheel-running behavior and maximal aerobic capacity (VO 2 max) during forced treadmill exercise. Femora from adult mice (average age 7.5 months) of the 11th generation of this selection experiment were μCT-scanned and three-dimensional virtual reconstructions of nutrient canals were measured for minimum cross-sectional area as a skeletal proxy of blood flow. Gross observations revealed that nutrient canals varied far more in number and shape than prior descriptions would indicate, regardless of sex or genetic background (i.e. HR vs. C lines). Canals adopted non-linear shapes and paths as they traversed from the periosteal to endosteal borders through the cortex, occasionally even branching within the cortical bone. Additionally, mice from both HR and C lines averaged more than four nutrient canals per femur, in contrast to the one to two nutrient canals described for femora from rats, pigs, and humans in prior literature. Mice from HR lines had significantly larger total nutrient canal area than C lines, which was the result not of an increase in the number of nutrient canals, but rather an increase in their average cross-section size. This study demonstrates that mice with an evolutionary history of increased locomotor activity and maximal aerobic metabolic rate have a concomitant increase in the size of their femoral nutrient canals. Although the primary determinant of nutrient canal size is currently not well understood, the present results bolster use of nutrient canal size as a skeletal indicator of aerobically supported levels of physical activity in comparative studies. © 2018 Anatomical Society.

Root proliferation in decaying roots and old root channels: A nutrient conservation mechanism in oligotrophic mangrove forests?

USGS Publications Warehouse

McKee, K.L.

2001-01-01

1. In oligotrophic habitats, proliferation of roots in nutrient-rich microsites may contribute to overall nutrient conservation by plants. Peat-based soils on mangrove islands in Belize are characterized by the presence of decaying roots and numerous old root channels (0.1-3.5 cm diameter) that become filled with living and highly branched roots of Rhizophora mangle and Avicennia germinans. The objectives of this study were to quantify the proliferation of roots in these microsites and to determine what causes this response. 2. Channels formed by the refractory remains of mangrove roots accounted for only 1-2% of total soil volume, but the proportion of roots found within channels varied from 9 to 24% of total live mass. Successive generations of roots growing inside increasingly smaller root channels were also found. 3. When artificial channels constructed of PVC pipe were buried in the peat for 2 years, those filled with nutrient-rich organic matter had six times more roots than empty or sand-filled channels, indicating a response to greater nutrient availability rather than to greater space or less impedance to root growth. 4. Root proliferation inside decaying roots may improve recovery of nutrients released from decomposing tissues before they can be leached or immobilized in this intertidal environment. Greatest root proliferation in channels occurred in interior forest zones characterized by greater soil waterlogging, which suggests that this may be a strategy for nutrient capture that minimizes oxygen losses from the whole root system. 5. Improved efficiency of nutrient acquisition at the individual plant level has implications for nutrient economy at the ecosystem level and may explain, in part, how mangroves persist and grow in nutrient-poor environments.

Ultra-processed foods and the limits of product reformulation.

PubMed

Scrinis, Gyorgy; Monteiro, Carlos Augusto

2018-01-01

The nutritional reformulation of processed food and beverage products has been promoted as an important means of addressing the nutritional imbalances in contemporary dietary patterns. The focus of most reformulation policies is the reduction in quantities of nutrients-to-limit - Na, free sugars, SFA, trans-fatty acids and total energy. The present commentary examines the limitations of what we refer to as 'nutrients-to-limit reformulation' policies and practices, particularly when applied to ultra-processed foods and drink products. Beyond these nutrients-to-limit, there are a range of other potentially harmful processed and industrially produced ingredients used in the production of ultra-processed products that are not usually removed during reformulation. The sources of nutrients-to-limit in these products may be replaced with other highly processed ingredients and additives, rather than with whole or minimally processed foods. Reformulation policies may also legitimise current levels of consumption of ultra-processed products in high-income countries and increased levels of consumption in emerging markets in the global South.

Impact of Frequency of Multi-Vitamin/Multi-Mineral Supplement Intake on Nutritional Adequacy and Nutrient Deficiencies in U.S. Adults.

PubMed

Blumberg, Jeffrey B; Frei, Balz B; Fulgoni, Victor L; Weaver, Connie M; Zeisel, Steven H

2017-08-09

Although >50% of U.S. adults use dietary supplements, little information is available on the impact of supplement use frequency on nutrient intakes and deficiencies. Based on nationally representative data in 10,698 adults from the National Health and Nutrition Examination Surveys (NHANES) 2009 to 2012, assessments were made of intakes from food alone versus food plus multi-vitamin/multi-mineral supplements (MVMS) of 17 nutrients with an Estimated Average Requirement (EAR) and a Tolerable Upper Intake Level (UL), and of the status of five nutrients with recognized biomarkers of deficiency. Compared to food alone, MVMS use at any frequency was associated with a lower prevalence of inadequacy ( p < 0.01) for 15/17 nutrients examined and an increased prevalence of intakes >UL for 7 nutrients, but the latter was ≤4% for any nutrient. Except for calcium, magnesium, and vitamin D, most frequent MVMS use (≥21 days/30 days) virtually eliminated inadequacies of the nutrients examined, and was associated with significantly lower odds ratios of deficiency for the examined nutrient biomarkers except for iron. In conclusion, among U.S. adults, MVMS use is associated with decreased micronutrient inadequacies, intakes slightly exceeding the UL for a few nutrients, and a lower risk of nutrient deficiencies.

A dynamic growth model of macroalgae: Application in an estuary recovering from treated wastewater and earthquake-driven eutrophication

NASA Astrophysics Data System (ADS)

Ren, Jeffrey S.; Barr, Neill G.; Scheuer, Kristin; Schiel, David R.; Zeldis, John

2014-07-01

A dynamic growth model of macroalgae was developed to predict growth of the green macroalga Ulva sp. in response to changes in environmental variables. The model is based on common physiological behaviour of macroalgae and hence has general applicability to macroalgae. Three state variables (nitrogen, carbon and phosphorus) were used to describe physiological processes and functional differences between nutrient and carbon uptakes. Carbon uptake is modelled as a function of temperature, light, algal internal state and water current, while nutrient uptake depends on internal state, temperature and environmental nutrient level. Growth can only occur when nutrients in the environment and in the internal storage pools (N-quota and P-quota) reach threshold levels. Physiological rates follow the Arrhenius relationship and increase exponentially with increasing temperature within the temperature tolerance range of a species. When parameterised and applied to Ulva sp. in the eutrophic Avon-Heathcote Estuary, New Zealand, the model generally reproduced field observations of Ulva sp. growth and abundance. Growth followed a clear seasonal cycle with biomass increasing from early-middle summer, reaching peak values in early autumn and then decreasing. Conversely, N-quotient levels were maximal during the winter months, declining during summer peak growth. These seasonal patterns were collectively driven by temperature, light intensity and nutrients. The model captured the N-quota and growth responses of Ulva sp. to the N-reduction arising from diversion of treated wastewater from the Avon-Heathcote Estuary to an offshore outfall in 2010, and of raw sewage N-discharges resulting from wastewater infrastructure damage caused by the Canterbury earthquakes in 2011. Sensitivity analyses revealed that temperature-related parameters and maximum uptake rate of C were among the most sensitive parameters in predicting biomass. In addition, the earthquake-derived changes in reduction of immersion time and decrease in the start biomass prior to summer blooms were shown to drive considerable declines in summer growth and biomass of Ulva sp.

The influence of nutrients, biliary-pancreatic secretions, and systemic trophic hormones on intestinal adaptation in a Roux-en-Y bypass model.

PubMed

Taqi, Esmaeel; Wallace, Laurie E; de Heuvel, Elaine; Chelikani, Prasanth K; Zheng, Huiyuan; Berthoud, Hans-Rudolph; Holst, Jens J; Sigalet, David L

2010-05-01

The signals that govern the upregulation of nutrient absorption (adaptation) after intestinal resection are not well understood. A Gastric Roux-en-Y bypass (GRYB) model was used to isolate the relative contributions of direct mucosal stimulation by nutrients, biliary-pancreatic secretions, and systemic enteric hormones on intestinal adaptation in short bowel syndrome. Male rats (350-400 g; n = 8/group) underwent sham or GRYB with pair feeding and were observed for 14 days. Weight and serum hormonal levels (glucagon-like peptide-2 [GLP-2], PYY) were quantified. Adaptation was assessed by intestinal morphology and crypt cell kinetics in each intestinal limb of the bypass and the equivalent points in the sham intestine. Mucosal growth factors and expression of transporter proteins were measured in each limb of the model. The GRYB animals lost weight compared to controls and exhibited significant adaptive changes with increased bowel width, villus height, crypt depth, and proliferation indices in the alimentary and common intestinal limbs. Although the biliary limb did not adapt at the mucosa, it did show an increased bowel width and crypt cell proliferation rate. The bypass animals had elevated levels of systemic PYY and GLP-2. At the mucosal level, insulin-like growth factor-1 (IGF-1) and basic fibroblast growth factor (bFGF) increased in all limbs of the bypass animals, whereas keratinocyte growth factor (KGF) and epidermal growth factor (EGF) had variable responses. The expression of the passive transporter of glucose, GLUT-2, expression was increased, whereas GLUT-5 was unchanged in all limbs of the bypass groups. Expression of the active mucosal transporter of glucose, SGLT-1 was decreased in the alimentary limb. Adaptation occurred maximally in intestinal segments stimulated by nutrients. Partial adaptation in the biliary limb may reflect the effects of systemic hormones. Mucosal content of IGF-1, bFGF, and EGF appear to be stimulated by systemic hormones, potentially GLP-2, whereas KGF may be locally regulated. Further studies to examine the relationships between the factors controlling nutrient-induced adaptation are suggested. Direct contact with nutrients appears to be the most potent factor in inducing mucosal adaptation. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Atlantic salmon (Salmo salar) require increased dietary levels of B-vitamins when fed diets with high inclusion of plant based ingredients

PubMed Central

Lock, Erik-Jan; Olsvik, Pål Asgeir; Hamre, Kristin; Espe, Marit; Torstensen, Bente Elisabeth; Silva, Joana; Hansen, Ann-Cecilie; Waagbø, Rune; Johansen, Johan S.; Sanden, Monica; Sissener, Nini H.

2016-01-01

Aiming to re-evaluate current recommendations for nutrient supplementations when Atlantic salmon are fed diets based on plant ingredients, two regression experiments, with parr and post-smolt, were conducted. A control diet was included to evaluate if ingredients supplied sufficient nutrients without any added nutrient package (NP). The nutrient package consisted of vitamins B, C, E, minerals, cholesterol, methionine, taurine and histidine. This paper focus on B-vitamins. In parr, growth, health and welfare parameters responded on NP additions, but this was not observed in the seawater stage. During three months of feeding, parr tripled their weight. Parr given diets added the NP above NRC (2011) showed improved protein retention, and reduced liver and viscera indices. Post-smolt fed the same diets during five months showed a doubling of weight, but did not respond to the variation in NP to the same extent as parr. Significant regressions were obtained in body compartments for several of the B-vitamins in the premix. Whole body biotin concentration was unaffected by micronutrient premix level, and mRNA expression of the enzymes dependent of biotin showed only weak increases with increased biotin. Muscle thiamine plateaued at a diet level similar to NRC (2011) recommendation in freshwater, and showed stable values independent on premix addition in seawater. The mRNA expression of the enzyme G6PDH (glucose-6-phosphate dehydrogenase) is sensitive to thiamine availability; results did not indicate any need to add thiamine above levels recommended for fish in general. Niacin showed a steady increase in whole body concentrations as feed niacin increased. Muscle riboflavin peaked at a diet level of 12.4 mg kg−1. Sufficient riboflavin is important to avoid e.g., development of cataract. Cataract was not registered to be any problem, neither in fresh- nor in seawater. Cobalamin (B 12) in muscle and liver was saturated at 0.17 mg kg−1 diet. Muscle pyridoxine showed a dose-dependent level in muscle, and peaked around 10 mg kg −1 diet. White muscle ASAT (asparagine amino transferase) activity steadily increased, with indications of stable values when dietary pyridoxine was around 10–16 mg kg −1 diet. Pantothenic acid increased in gill tissue up to a level of 5.5 mg kg −1 soft gill tissue; at a dietary level of 22 mg kg−1. Improved performance, and coverage of metabolic need for niacin was at a dietary level of 66 mg kg −1, riboflavin 10–12 mg kg−1, pyridoxine 10 mg kg−1 and panthotenic acid 22 mg kg−1. Based on these results, recommended B-vitamin supplementation in plant based diets for Atlantic salmon should be adjusted. PMID:27703849

Effects of Inclusion Levels of Wheat Bran and Body Weight on Ileal and Fecal Digestibility in Growing Pigs

PubMed Central

Huang, Q.; Su, Y. B.; Li, D. F.; Liu, L.; Huang, C. F.; Zhu, Z. P.; Lai, C. H.

2015-01-01

The objective of this study was to determine the effects of graded inclusions of wheat bran (0%, 9.65%, 48.25% wheat bran) and two growth stages (from 32.5 to 47.2 kg and 59.4 to 78.7 kg, respectively) on the apparent ileal digestibility (AID), apparent total tract digestibility (ATTD) and hindgut fermentation of nutrients and energy in growing pigs. Six light pigs (initial body weight [BW] 32.5±2.1 kg) and six heavy pigs (initial BW 59.4±3.2 kg) were surgically prepared with a T-cannula in the distal ileum. A difference method was used to calculate the nutrient and energy digestibility of wheat bran by means of comparison with a basal diet consisting of corn-soybean meal (0% wheat bran). Two additional diets were formulated by replacing 9.65% and 48.25% wheat bran by the basal diet, respectively. Each group of pigs was allotted to a 6×3 Youden square design, and pigs were fed to three experimental diets during three 11-d periods. Hindgut fermentation values were calculated as the differences between ATTD and AID values. For the wheat bran diets, the AID and ATTD of dry matter (DM), ash, organic matter (OM), carbohydrates (CHO), gross energy (GE), and digestible energy (DE) decreased with increasing inclusion levels of wheat bran (p<0.05). While only AID of CHO and ATTD of DM, ash, OM, CHO, GE, and DE content differed (p<0.05) when considering the BW effect. For the wheat bran ingredient, there was a wider variation effect (p<0.01) on the nutrient and energy digestibility of wheat bran in 9.65% inclusion level due to the coefficient of variation (CV) of the nutrient and energy digestibility being higher at 9.65% compared to 48.25% inclusion level of wheat bran. Digestible energy content of wheat bran at 48.25% inclusion level (4.8 and 6.7 MJ/kg of DM, respectively) fermented by hindgut was significantly higher (p<0.05) than that in 9.65% wheat bran inclusion level (2.56 and 2.12 MJ/kg of DM, respectively), which was also affected (p<0.05) by two growth stages. This increase in hindgut fermentation caused the difference in ileal DE (p<0.05) to disappear at total tract level. All in all, increasing wheat bran levels in diets negatively influences the digestibility of some nutrients in pigs, while it positively affects the DE fermentation in the hindgut. PMID:25925062

Effects of different levels of supplementation of a 50:50 mixture of molasses:crude glycerol on performance, Bermuda grass hay intake, and nutrient digestibility of beef cattle.

PubMed

Ciriaco, F M; Henry, D D; Mercadante, V R G; Schulmeister, T; Ruiz-Moreno, M; Lamb, G C; DiLorenzo, N

2015-05-01

Two experiments were performed to evaluate the effects of different levels of supplementation with a 50:50 (as-fed) mixture of molasses:crude glycerol on animal performance, total tract digestibility of nutrients, and ruminal in situ degradability of nutrients in beef heifers and steers consuming Tifton 85 Bermuda grass (Cynodon spp.) hay. For Exp. 1, 24 Angus crossbred heifers (380 ± 31 kg BW) were used in a generalized randomized block design. For Exp. 2, 8 ruminally cannulated Angus crossbred steers (323 ± 42 kg BW) were used in a 4 × 4 duplicated Latin square design. For both experiments, animals were housed in individual pens at the University of Florida Feed Efficiency Facility, had ad libitum access to Tifton 85 Bermuda grass hay, and were randomly assigned to 1 of 4 treatments: 1) CTRL, no supplementation; 2) SUP1, 0.45 kg/d (as fed) of 50:50 mixture; 3) SUP3, 1.36 kg/d (as fed) of 50:50 mixture; and 4) SUP5, 2.27 kg/d (as fed) of a 50:50 mixture. Individual feed intake was recorded. Total DMI increased linearly (P = 0.005) as the level of supplementation increased. Hay intake ranged from 1.36 (CTRL) to 1.23% (SUP5) of BW, and was not affected (P ≥ 0.10) by liquid supplementation. Final BW was not affected by liquid supplementation ( ≥ 0.10). There was a linear increase (P = 0.027) in ADG as the liquid supplementation amounts increased. Liquid supplementation did not affect G:F (P ≥ 0.10). Apparent total tract digestibility of DM, OM, NDF, and ADF increased linearly (P < 0.001), while CP total tract digestibility decreased linearly (P = 0.002) as the level of supplementation increased. Ruminal pH was decreased linearly (P = 0.012) as the level of supplementation increased. No effect (P ≥ 0.10) of liquid supplementation was detected on lag time for NDF and ADF content of bermudagrass hay; however, rate of degradation (Kd) of NDF tended (P = 0.076) to be affected cubically by liquid supplementation. In addition, liquid supplementation linearly decreased (P < 0.05) ED of OM, CP, NDF, and ADF. In conclusion, supplementing up to 2.27 kg/d of a 50:50 mixture of molasses:crude glycerol may stimulate microbial growth and fermentative activity, thereby increasing nutrient digestibility. Increased fiber digestion, along with energy supplementation, led to increased ADG in heifers consuming Bermuda grass hay.

Nutrient-deprived cancer cells preferentially use sialic acid to maintain cell surface glycosylation.

PubMed

Badr, Haitham A; AlSadek, Dina M M; Mathew, Mohit P; Li, Chen-Zhong; Djansugurova, Leyla B; Yarema, Kevin J; Ahmed, Hafiz

2015-11-01

Cancer is characterized by abnormal energy metabolism shaped by nutrient deprivation that malignant cells experience during various stages of tumor development. This study investigated the response of nutrient-deprived cancer cells and their non-malignant counterparts to sialic acid supplementation and found that cells utilize negligible amounts of this sugar for energy. Instead cells use sialic acid to maintain cell surface glycosylation through complementary mechanisms. First, levels of key metabolites (e.g., UDP-GlcNAc and CMP-Neu5Ac) required for glycan biosynthesis are maintained or enhanced upon Neu5Ac supplementation. In concert, sialyltransferase expression increased at both the mRNA and protein levels, which facilitated increased sialylation in biochemical assays that measure sialyltransferase activity as well as at the whole cell level. In the course of these experiments, several important differences emerged that differentiated the cancer cells from their normal counterparts including resistant to sialic acid-mediated energy depletion, consistently more robust sialic acid-mediated glycan display, and distinctive cell surface vs. internal vesicle display of newly-produced sialoglycans. Finally, the impact of sialic acid supplementation on specific markers implicated in cancer progression was demonstrated by measuring levels of expression and sialylation of EGFR1 and MUC1 as well as the corresponding function of sialic acid-supplemented cells in migration assays. These findings both provide fundamental insight into the biological basis of sialic acid supplementation of nutrient-deprived cancer cells and open the door to the development of diagnostic and prognostic tools. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of increasing levels of apparent metabolizable energy on laying hens in barn system.

PubMed

Kang, Hwan Ku; Park, Seong Bok; Jeon, Jin Joo; Kim, Hyun Soo; Park, Ki Tae; Kim, Sang Ho; Hong, Eui Chul; Kim, Chan Ho

2018-04-12

This experiment was to investigate the effect of increasing levels of apparent metabolizable energy (AMEn) on the laying performance, egg quality, blood parameter, blood biochemistry, intestinal morphology, and apparent total tract digestibility (ATTD) of energy and nutrients in diets fed to laying hens. A total of three-hundred twenty 33-week-old Hy-Line Brown laying hens (Gallus domesticus) were evenly assigned to four experimental diets of 2,750, 2,850, 2,950, and 3,050 kcal AMEn/kg in floor with deep litter of rice hulls. There were four replicates of each treatment, each consisting of 20 birds in a pen. AMEn intake was increased (linear, p < 0.05) with inclusion level of AMEn in diets increased. Feed intake and feed conversion ratio were improved (linear, p < 0.01), but hen-day egg production tended to be increased as increasing level of AMEn in diets increased. During the experiment, leukocyte concentration and blood biochemistry (total cholesterol, triglyceride, glucose, total protein, calcium, asparate aminotransferase (AST), and alanine transferase (ALT) were not influenced by increasing level of AMEn in diets. Gross energy and ether extract were increased (linear, p < 0.01) with inclusion level of AMEn in diets increased. Laying hens fed high AMEn diet (i.e., 3,050 kcal/kg in the current experiment) tended to overconsume energy with a positive effect on feed intake, feed conversion ratio, nutrient digestibility, and intestinal morphology but not in egg production and egg mass.

Succession of microbial communities and changes of incremental oil in a post-polymer flooded reservoir with nutrient stimulation.

PubMed

Gao, Peike; Li, Guoqiang; Le, Jianjun; Liu, Xiaobo; Liu, Fang; Ma, Ting

2018-02-01

Further exploitation of the residual oil underground in post-polymer flooded reservoirs is attractive and challengeable. In this study, indigenous microbial enhanced oil recovery (IMEOR) in a post-polymer flooded reservoir was performed. The succession of microbial communities was revealed by high-throughput sequencing of 16S rRNA genes and changes of incremental oil were analyzed. The results indicated that the abundances of reservoir microorganisms significantly increased, with alpha diversities decreased in the IMEOR process. With the intermittent nutrient injection, microbial communities showed a regular change and were alternately dominated by minority populations: Pseudomonas and Acinetobacter significantly increased when nutrients were injected; Thauera, Azovibrio, Arcobacter, Helicobacter, Desulfitobacterium, and Clostridium increased in the following water-flooding process. Accompanied by the stimulated populations, higher oil production was obtained. However, these populations did not contribute a persistent level of incremental oil in the reservoir. In summary, this study revealed the alternative succession of microbial communities and the changes of incremental oil in a post-polymer flooded reservoir with intermittent nutrient stimulation process.

Functioning of a Shallow-Water Sediment System during Experimental Warming and Nutrient Enrichment

PubMed Central

Alsterberg, Christian; Sundbäck, Kristina; Hulth, Stefan

2012-01-01

Effects of warming and nutrient enrichment on intact unvegetated shallow-water sediment were investigated for 5 weeks in the autumn under simulated natural field conditions, with a main focus on trophic state and benthic nitrogen cycling. In a flow-through system, sediment was exposed to either seawater at ambient temperature or seawater heated 4°C above ambient, with either natural or nutrient enriched water. Sediment–water fluxes of oxygen and inorganic nutrients, nitrogen mineralization, and denitrification were measured. Warming resulted in an earlier shift to net heterotrophy due to increased community respiration; primary production was not affected by temperature but (slightly) by nutrient enrichment. The heterotrophic state was, however, not further strengthened by warming, but was rather weakened, probably because increased mineralization induced a shortage of labile organic matter. Climate-related warming of seawater during autumn could therefore, in contrast to previous predictions, induce shorter but more intensive heterotrophic periods in shallow-water sediments, followed by longer autotrophic periods. Increased nitrogen mineralization and subsequent effluxes of ammonium during warming suggested a preferential response of organisms driving nitrogen mineralization when compared to sinks of ammonium such as nitrification and algal assimilation. Warming and nutrient enrichment resulted in non-additive effects on nitrogen mineralization and denitrification (synergism), as well as on benthic fluxes of phosphate (antagonism). The mode of interaction appears to be related to the trophic level of the organisms that are the main drivers of the affected processes. Despite the weak response of benthic microalgae to both warming and nutrient enrichment, the assimilation of nitrogen by microalgae was similar in magnitude to rates of nitrogen mineralization. This implies a sustained filter function and retention capacity of nutrients by the sediment. PMID:23240032

Transcriptomic response of the red tide dinoflagellate, Karenia brevis, to nitrogen and phosphorus depletion and addition.

PubMed

Morey, Jeanine S; Monroe, Emily A; Kinney, Amanda L; Beal, Marion; Johnson, Jillian G; Hitchcock, Gary L; Van Dolah, Frances M

2011-07-05

The role of coastal nutrient sources in the persistence of Karenia brevis red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' trans-spliced leader (SL) sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of K. brevis is responsive to nitrogen and phosphorus and is informative of nutrient status. Microarray analysis of N-depleted K. brevis cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases) relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10-4. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR) proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes. Microarray analysis provided transcriptomic evidence for N- but not P-limitation in K. brevis. Transcriptomic responses to the addition of either N or P suggest a concerted program leading to the reactivation of chloroplast functions. Even the earliest responding PPR protein transcripts possess a 5' SL sequence that suggests post-transcriptional control. Given the current state of knowledge of dinoflagellate gene regulation, it is currently unclear how these rapid changes in such transcript levels are achieved.

Eating behavior during dexamethasone treatment in children with acute lymphoblastic leukemia.

PubMed

Warris, Lidewij T; van den Akker, Erica L T; Bierings, Marc B; van den Bos, Cor; Aarsen, Femke K; Zwaan, Michel C; Tissing, Wim J E; Veening, Margreet A; Pieters, Rob; van den Heuvel-Eibrink, Marry M

2017-12-01

Large prospective studies on dexamethasone-induced changes in eating behavior, energy, and nutrient intake are lacking in pediatric acute lymphoblastic leukemia (ALL). We prospectively studied eating behavior, energy, nutrient intake, and the effect on leptin and adiponectin levels during dexamethasone administration in children with ALL. Parents of patients with ALL (3-16 years) completed a dietary diary for their child during 4 days of dexamethasone (6 mg/m 2 ) administration. Energy intake and nutrient intake (energy percentage = E%) were assessed and compared with the recommended intake. The Dutch Eating Behavior Questionnaire for Children was completed before start and after 4 days of dexamethasone administration by patients of 7-12 years of age. Fasting leptin and adiponectin levels were also measured before start and after 4 days of dexamethasone administration. Energy intake per day(kcal) (N = 44) increased significantly during dexamethasone (median day 1: 1,103 (717-1,572) versus day 4: 1,482 (1,176-1,822), P < 0.01), including an increase in total protein, fat, saturated fat, carbohydrate, and sodium intake. Intake of saturated fat (median day 4: 12 E%) and salt (median day 4: 1.9 g/day) exceeded the healthy range for age and gender. With respect to eating behavior, dexamethasone significantly decreased restrained eating (P = 0.04). Leptin levels as well as adiponectin levels increased significantly during the dexamethasone course. Four days of dexamethasone treatment significantly increased energy intake, including excessive saturated fat and salt intake, and changed eating behavior in children with ALL. Nutritional and behavioral interventions during dexamethasone treatment are recommended to stimulate a healthy lifestyle. © 2017 Wiley Periodicals, Inc.

The influence of residue removal and prescribed fire on distributions of forest nutrients.

Treesearch

Little; S.N.; G.O. Klock

1985-01-01

The effects of two levels of residue removal (removal of all woody material larger than 15 x 180 cm and 10 x 120 cm) on the distribution of nitrogen and sulfur on the forest site and the added effects of post-harvest prescribed fire on those distributions were studied at two sites in the Cascade Range in Oregon. Nutrients lost from increased removal of residue were...

The effects of CO2 and nutrient fertilisation on the growth and temperature response of the mangrove Avicennia germinans.

PubMed

Reef, Ruth; Slot, Martijn; Motro, Uzi; Motro, Michal; Motro, Yoav; Adame, Maria F; Garcia, Milton; Aranda, Jorge; Lovelock, Catherine E; Winter, Klaus

2016-08-01

In order to understand plant responses to both the widespread phenomenon of increased nutrient inputs to coastal zones and the concurrent rise in atmospheric CO2 concentrations, CO2-nutrient interactions need to be considered. In addition to its potential stimulating effect on photosynthesis and growth, elevated CO2 affects the temperature response of photosynthesis. The scarcity of experiments testing how elevated CO2 affects the temperature response of tropical trees hinders our ability to model future primary productivity. In a glasshouse study, we examined the effects of elevated CO2 (800 ppm) and nutrient availability on seedlings of the widespread mangrove Avicennia germinans. We assessed photosynthetic performance, the temperature response of photosynthesis, seedling growth and biomass allocation. We found large synergistic gains in both growth (42 %) and photosynthesis (115 %) when seedlings grown under elevated CO2 were supplied with elevated nutrient concentrations relative to their ambient growing conditions. Growth was significantly enhanced under elevated CO2 only under high-nutrient conditions, mainly in above-ground tissues. Under low-nutrient conditions and elevated CO2, root volume was more than double that of seedlings grown under ambient CO2 levels. Elevated CO2 significantly increased the temperature optimum for photosynthesis by ca. 4 °C. Rising CO2 concentrations are likely to have a significant positive effect on the growth rate of A. germinans over the next century, especially in areas where nutrient availability is high.

Nutrients content and quality of liquid fertilizer made from goat manure

NASA Astrophysics Data System (ADS)

Sunaryo, Yacobus; Purnomo, Djoko; Theresia Darini, Maria; Ratri Cahyani, Vita

2018-05-01

Quality of liquid fertilizer is determined by the content of nutrients and other chemical factors such as pH and EC. This research aimed to examine nutrient contents and dynamic of pH and EC of liquid fertilizer made from goat manure in combination with sugar and ammonium sulfate (ZA) and using Effective Microorganisms (EM) as the decomposer. This research was conducted by employing 3 x 3 factorial experiment with three replications. Each treatment combination was applied in 20 L of water. The first factor was the quantity of sugar which consisted of 3 levels: 12.5, 25, and 50 g L-1 of water. The second factor was the quantity of ZA which consisted of 3 levels: 25, 37.5, and 50 g L-1 of water. All combinations were added by 100 g of air dried goat manure L-1 of water and EM solution 1 ml L-1 of water, and incubated for five months. Results of the experiment indicated that the increasing concentration of ZA resulted in the significantly increase of N total and S total. Increasing concentration of sugar resulted in decreasing pH and increasing lactic acid; whereas, increasing concentration of ZA followed by increasing Electrical Conductivity (EC). There was no significantly change of pH and EC of the liquid fertilizer during five months incubation.

Ocean Acidification Accelerates the Growth of Two Bloom-Forming Macroalgae

PubMed Central

Young, Craig S.; Gobler, Christopher J.

2016-01-01

While there is growing interest in understanding how marine life will respond to future ocean acidification, many coastal ecosystems currently experience intense acidification in response to upwelling, eutrophication, or riverine discharge. Such acidification can be inhibitory to calcifying animals, but less is known regarding how non-calcifying macroalgae may respond to elevated CO2. Here, we report on experiments performed during summer through fall with North Atlantic populations of Gracilaria and Ulva that were grown in situ within a mesotrophic estuary (Shinnecock Bay, NY, USA) or exposed to normal and elevated, but environmentally realistic, levels of pCO2 and/or nutrients (nitrogen and phosphorus). In nearly all experiments, the growth rates of Gracilaria were significantly increased by an average of 70% beyond in situ and control conditions when exposed to elevated levels of pCO2 (p<0.05), but were unaffected by nutrient enrichment. In contrast, the growth response of Ulva was more complex as this alga experienced significantly (p<0.05) increased growth rates in response to both elevated pCO2 and elevated nutrients and, in two cases, pCO2 and nutrients interacted to provide a synergistically enhanced growth rate for Ulva. Across all experiments, elevated pCO2 significantly increased Ulva growth rates by 30% (p<0.05), while the response to nutrients was smaller (p>0.05). The δ13C content of both Gracilaria and Ulva decreased two-to-three fold when grown under elevated pCO2 (p<0.001) and mixing models demonstrated these macroalgae experienced a physiological shift from near exclusive use of HCO3- to primarily CO2 use when exposed to elevated pCO2. This shift in carbon use coupled with significantly increased growth in response to elevated pCO2 suggests that photosynthesis of these algae was limited by their inorganic carbon supply. Given that eutrophication can yield elevated levels of pCO2, this study suggests that the overgrowth of macroalgae in eutrophic estuaries can be directly promoted by acidification, a process that will intensify in the coming decades. PMID:27176637

Ocean Acidification Accelerates the Growth of Two Bloom-Forming Macroalgae.

PubMed

Young, Craig S; Gobler, Christopher J

2016-01-01

While there is growing interest in understanding how marine life will respond to future ocean acidification, many coastal ecosystems currently experience intense acidification in response to upwelling, eutrophication, or riverine discharge. Such acidification can be inhibitory to calcifying animals, but less is known regarding how non-calcifying macroalgae may respond to elevated CO2. Here, we report on experiments performed during summer through fall with North Atlantic populations of Gracilaria and Ulva that were grown in situ within a mesotrophic estuary (Shinnecock Bay, NY, USA) or exposed to normal and elevated, but environmentally realistic, levels of pCO2 and/or nutrients (nitrogen and phosphorus). In nearly all experiments, the growth rates of Gracilaria were significantly increased by an average of 70% beyond in situ and control conditions when exposed to elevated levels of pCO2 (p<0.05), but were unaffected by nutrient enrichment. In contrast, the growth response of Ulva was more complex as this alga experienced significantly (p<0.05) increased growth rates in response to both elevated pCO2 and elevated nutrients and, in two cases, pCO2 and nutrients interacted to provide a synergistically enhanced growth rate for Ulva. Across all experiments, elevated pCO2 significantly increased Ulva growth rates by 30% (p<0.05), while the response to nutrients was smaller (p>0.05). The δ13C content of both Gracilaria and Ulva decreased two-to-three fold when grown under elevated pCO2 (p<0.001) and mixing models demonstrated these macroalgae experienced a physiological shift from near exclusive use of HCO3- to primarily CO2 use when exposed to elevated pCO2. This shift in carbon use coupled with significantly increased growth in response to elevated pCO2 suggests that photosynthesis of these algae was limited by their inorganic carbon supply. Given that eutrophication can yield elevated levels of pCO2, this study suggests that the overgrowth of macroalgae in eutrophic estuaries can be directly promoted by acidification, a process that will intensify in the coming decades.

Performance and carcass yield of crossbred dairy steers fed diets with different levels of concentrate.

PubMed

da Silva, Gabriel Santana; Chaves Véras, Antônia Sherlanea; de Andrade Ferreira, Marcelo; Moreira Dutra, Wilson; Menezes Wanderley Neves, Maria Luciana; Oliveira Souza, Evaristo Jorge; Ramos de Carvalho, Francisco Fernando; de Lima, Dorgival Morais

2015-10-01

The objective of this study was to evaluate the influence of diets with increasing concentrate levels (170, 340, 510 and 680 g/kg of total dry matter) on dry matter intake, digestibility, performance and carcass characteristics of 25 Holstein-Zebu crossbred dairy steers in a feedlot. A completely randomized design was used, and data were submitted to analysis of variance and regression. The dry matter intake and digestibility coefficients of all nutrients increased linearly. The total weight gain and average daily gain added 1.16 kg and 9.90 g, respectively, for each 10 g/kg increase in concentrate. The empty body weight, hot carcass weight and cold carcass weight responded linearly to increasing concentrate. The hot carcass yield and cold carcass yield, gains in empty body weight and carcass gain were also influenced, as were the efficiencies of carcass deposition and carcass deposition rate. It is concluded that increasing concentrate levels in feedlot diets increase the intake and digestibility of dry matter and other nutrients, improving the feed efficiency, performance and physical characteristics of the carcass. Furthermore and of importance concerning the climate change debate, evidence from the literature indicates that enteric methane production would be reduced with increasing concentrate levels such as those used.

Citric acid assisted phytoremediation of copper by Brassica napus L.

PubMed

Zaheer, Ihsan Elahi; Ali, Shafaqat; Rizwan, Muhammad; Farid, Mujahid; Shakoor, Muhammad Bilal; Gill, Rafaqa Ali; Najeeb, Ullah; Iqbal, Naeem; Ahmad, Rehan

2015-10-01

Use of organic acids for promoting heavy metals phytoextraction is gaining worldwide attention. The present study investigated the influence of citric acid (CA) in enhancing copper (Cu) uptake by Brassica napus L. seedlings. 6 Weeks old B. napus seedlings were exposed to different levels of copper (Cu, 0, 50 and 100µM) alone or with CA (2.5mM) in a nutrient medium for 40 days. Exposure to elevated Cu levels (50 and 100µM) significantly reduced the growth, biomass production, chlorophyll content, gas exchange attributes and soluble proteins of B. napus seedlings. In addition, Cu toxicity increased the production of hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage (EL) in leaf and root tissues of B. napus. Activities of antioxidant enzymes such as guaiacol peroxidase (POD), superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX) in root and shoot tissues of B. napus were increased in response to lower Cu concentration (50µM) but increased under higher Cu concentration (100µM). Addition of CA into nutrient medium significantly alleviated Cu toxicity effects on B. napus seedlings by improving photosynthetic capacity and ultimately plant growth. Increased activities of antioxidant enzymes in CA-treated plants seems to play a role in capturing of stress-induced reactive oxygen species as was evident from lower level of H2O2, MDA and EL in CA-treated plants. Increasing Cu concentration in the nutrient medium significantly increased Cu concentration in in B. napus tissues. Cu uptake was further increased by CA application. These results suggested that CA might be a useful strategy for increasing phytoextraction of Cu from contaminated soils. Copyright © 2015 Elsevier Inc. All rights reserved.

Selenite modulates the level of phenolics and nutrient element to alleviate the toxicity of arsenite in rice (Oryza sativa L.).

PubMed

Chauhan, Reshu; Awasthi, Surabhi; Tripathi, Preeti; Mishra, Seema; Dwivedi, Sanjay; Niranjan, Abhishek; Mallick, Shekhar; Tripathi, Pratibha; Pande, Veena; Tripathi, Rudra Deo

2017-04-01

Arsenic (As) contamination of paddy rice is a serious threat all over the world particularly in South East Asia. Selenium (Se) plays important role in protection of plants against various abiotic stresses including heavy metals. Moreover, arsenite (AsIII) and selenite (SeIV) can be biologically antagonistic due to similar electronic configuration and sharing the common transporter for their uptake in plant. In the present study, the response of oxidative stress, phenolic compounds and nutrient elements was analyzed to investigate Se mediated As tolerance in rice seedlings during AsIII and SeIV exposure in hydroponics. Selenite (25µM) significantly decreased As accumulation in plant than As (25µM) alone treated plants. Level of oxidative stress related parameters viz., reactive oxygen species (ROS), lipid peroxidation, electrical conductivity, nitric oxide and pro-oxidant enzyme (NADPH oxidase), were in the order of As>As+Se>control>Se. Selenium ameliorated As phytotoxicity by increased level of phenolic compounds particularly gallic acid, protocatechuic acid, ferulic acid and rutin and thiol metabolism related enzymes viz., serine acetyl transferase (SAT) and cysteine synthase (CS). Selenium supplementation enhanced the uptake of nutrient elements viz., Fe, Mn, Co, Cu, Zn, Mo, and improved plant growth. The results concluded that Se addition in As contaminated environment might be an important strategy to reduce As uptake and associated phytotoxicity in rice plant by modulation of phenolic compounds and increased uptake of nutrient elements. Copyright © 2016 Elsevier Inc. All rights reserved.

Research to Inform Nutrient Thresholds and Prioritization of ...

EPA Pesticide Factsheets

The information in this presentation focuses on SSWR's 4.02 project, which will advance the science needed to inform decisions to prioritize watersheds and nutrient sources for nutrient management and define appropriate nutrient levels for the nation’s waters, two important elements of EPA’s framework for managing nutrient pollution. The information in this presentation focuses on SSWR's 4.02 project, which will advance the science needed to inform decisions to prioritize watersheds and nutrient sources for nutrient management and define appropriate nutrient levels for the nation’s waters, two important elements of EPA’s framework for managing nutrient pollution.

Growth, yield and movement of phosphate nutrients in soybean on P fertilizer, straw mulch and difference of plant spacing

NASA Astrophysics Data System (ADS)

Hanum, C.

2018-02-01

Soybean is one of the plants that require much amounts of phosphate. P nutrient, microclimate modification and plant spacing arrangement is the efforts to improve grain yield. The objective of the research was to study the effect of P fertilization, mulching straw and plant spacing on growth, yield and movement of P nutrient on soybean. The study was conducted at Cengkeh Turi Binjai using factorial randomized block design with 3 factors. The first factors was P fertilizer 0, 100, and 200 kg/ha, the second factor was thickness of rice straw mulch 0 and 5 cm, and third factors was plant spacing 30 cm x 15 cm, 40 cm x 20 cm, and 50 cm x 25 cm. The results of the research showed that phosphate fertilizer (200 kg/ha) significantly increased levels of phosphate in the shoot. Plant spacing (50 cm x 25 cm) increased root volume. The interaction of phosphate fertilizer (200 kg/ha) and spacing (50 cm x 25 cm) increased the phosphate level by 93.33% in shoot. Plant spacing (50 cm x 25 cm) produced the largest of 100 grains weight as compared to other plant spacing.

The rise of algae in Cryogenian oceans and the emergence of animals

NASA Astrophysics Data System (ADS)

Brocks, Jochen J.; Jarrett, Amber J. M.; Sirantoine, Eva; Hallmann, Christian; Hoshino, Yosuke; Liyanage, Tharika

2017-08-01

The transition from dominant bacterial to eukaryotic marine primary productivity was one of the most profound ecological revolutions in the Earth’s history, reorganizing the distribution of carbon and nutrients in the water column and increasing energy flow to higher trophic levels. But the causes and geological timing of this transition, as well as possible links with rising atmospheric oxygen levels and the evolution of animals, remain obscure. Here we present a molecular fossil record of eukaryotic steroids demonstrating that bacteria were the only notable primary producers in the oceans before the Cryogenian period (720-635 million years ago). Increasing steroid diversity and abundance marks the rapid rise of marine planktonic algae (Archaeplastida) in the narrow time interval between the Sturtian and Marinoan ‘snowball Earth’ glaciations, 659-645 million years ago. We propose that the incumbency of cyanobacteria was broken by a surge of nutrients supplied by the Sturtian deglaciation. The ‘Rise of Algae’ created food webs with more efficient nutrient and energy transfers, driving ecosystems towards larger and increasingly complex organisms. This effect is recorded by the concomitant appearance of biomarkers for sponges and predatory rhizarians, and the subsequent radiation of eumetazoans in the Ediacaran period.

The rise of algae in Cryogenian oceans and the emergence of animals.

PubMed

Brocks, Jochen J; Jarrett, Amber J M; Sirantoine, Eva; Hallmann, Christian; Hoshino, Yosuke; Liyanage, Tharika

2017-08-31

The transition from dominant bacterial to eukaryotic marine primary productivity was one of the most profound ecological revolutions in the Earth's history, reorganizing the distribution of carbon and nutrients in the water column and increasing energy flow to higher trophic levels. But the causes and geological timing of this transition, as well as possible links with rising atmospheric oxygen levels and the evolution of animals, remain obscure. Here we present a molecular fossil record of eukaryotic steroids demonstrating that bacteria were the only notable primary producers in the oceans before the Cryogenian period (720-635 million years ago). Increasing steroid diversity and abundance marks the rapid rise of marine planktonic algae (Archaeplastida) in the narrow time interval between the Sturtian and Marinoan 'snowball Earth' glaciations, 659-645 million years ago. We propose that the incumbency of cyanobacteria was broken by a surge of nutrients supplied by the Sturtian deglaciation. The 'Rise of Algae' created food webs with more efficient nutrient and energy transfers, driving ecosystems towards larger and increasingly complex organisms. This effect is recorded by the concomitant appearance of biomarkers for sponges and predatory rhizarians, and the subsequent radiation of eumetazoans in the Ediacaran period.

Processed Food Contributions to Energy and Nutrient Intake Differ among US Children by Race/Ethnicity.

PubMed

Eicher-Miller, Heather A; Fulgoni, Victor L; Keast, Debra R

2015-12-02

This study determined and compared the mean daily intake of energy and nutrients from processed foods by level of processing (minimally processed; processed for preservation, nutrient enhancement, and freshness; mixtures of combined ingredients; ready-to-eat processed foods; and prepared foods/meals) among non-Hispanic white, non-Hispanic black, and Mexican American US children. Data from participants 2-18 years old (n = 10,298) of the nationally representative cross-sectional National Health and Nutrition Examination Survey 2003-2008 with a complete one day, 24-h dietary recall were used to determine mean intake of energy and nutrients recommended for increase and decrease, as per the 2010 Dietary Guidelines for Americans, among child race/ethnic groups by category of food processing. Regression analysis was used to estimate and compare covariate-adjusted (gender, age, and poverty-income-level) least square means (p < 0.05/3 race/ethnic groups). All children, regardless of race or ethnicity consumed processed foods. Approximately 66% to 84% of total daily energy, saturated fat, cholesterol, fiber, total sugar, added sugars, calcium, vitamin D, potassium, and sodium intake are contributed by one of the five categories of processed foods. Clinicians and policy should primarily advise consideration of the energy and nutrient composition of foods, rather than the processing level, when selecting a healthy diet for children.

Processed Food Contributions to Energy and Nutrient Intake Differ among US Children by Race/Ethnicity

PubMed Central

Eicher-Miller, Heather A.; Fulgoni, Victor L.; Keast, Debra R.

2015-01-01

This study determined and compared the mean daily intake of energy and nutrients from processed foods by level of processing (minimally processed; processed for preservation, nutrient enhancement, and freshness; mixtures of combined ingredients; ready-to-eat processed foods; and prepared foods/meals) among non-Hispanic white, non-Hispanic black, and Mexican American US children. Data from participants 2–18 years old (n = 10,298) of the nationally representative cross-sectional National Health and Nutrition Examination Survey 2003–2008 with a complete one day, 24-h dietary recall were used to determine mean intake of energy and nutrients recommended for increase and decrease, as per the 2010 Dietary Guidelines for Americans, among child race/ethnic groups by category of food processing. Regression analysis was used to estimate and compare covariate-adjusted (gender, age, and poverty-income-level) least square means (p < 0.05/3 race/ethnic groups). All children, regardless of race or ethnicity consumed processed foods. Approximately 66% to 84% of total daily energy, saturated fat, cholesterol, fiber, total sugar, added sugars, calcium, vitamin D, potassium, and sodium intake are contributed by one of the five categories of processed foods. Clinicians and policy should primarily advise consideration of the energy and nutrient composition of foods, rather than the processing level, when selecting a healthy diet for children. PMID:26633491

Climate Variability Impacts on Watershed Nutrient Delivery and Reservoir Production

NASA Astrophysics Data System (ADS)

White, J. D.; Prochnow, S. J.; Zygo, L. M.; Byars, B. W.

2005-05-01

Reservoirs in agricultural dominated watersheds tend to exhibit pulse-system behavior especially if located in climates dominated by summer convective precipitation inputs. Concentration and bulk mass of nutrient and sediment inputs into reservoir systems vary in terms of timing and magnitude of delivery from watershed sources to reservoirs under these climate conditions. Reservoir management often focuses on long-term average inputs without considering short and long-term impacts of variation in loading. In this study we modeled a watershed-reservoir system to assess how climate variability affects reservoir primary production through shifts in external loading and internal recycling of limiting nutrients. The Bosque watershed encompasses 423,824 ha in central Texas which delivers water to Lake Waco, a 2900 ha reservoir that is the primary water source for the city of Waco and surrounding areas. Utilizing the Soil Water Assessment Tool for the watershed and river simulations and the CE-Qual-2e model for the reservoir, hydrologic and nutrient dynamics were simulated for a 10 year period encompassing two ENSO cycles. The models were calibrated based on point measurement of water quality attributes for a two year time period. Results indicated that watershed delivery of nutrients was affected by the presence and density of small flood-control structure in the watershed. However, considerable nitrogen and phosphorus loadings were derived from soils in the upper watershed which have had long-term waste-application from concentrated animal feeding operations. During El Niño years, nutrient and sediment loads increased by 3 times above non-El Niño years. The simulated response within the reservoir to these nutrient and sediment loads had both direct and indirect. Productivity evaluated from chlorophyll a and algal biomass increased under El Niño conditions, however species composition shifts were found with an increase in cyanobacteria dominance. In non-El Niño years, species composition was more evenly distributed. At the longer time scale, El Niño events with accompanying increase in nutrient loads were followed by years in which productivity declined below levels predicted solely by nutrient ratios. This was due to subtle shifts in organic matter decomposition where productive years are followed by increases in refractory material which sequesters nutrients and reduces internal loading.

Impacts of Cover Crops on Water and Nutrient Dynamics in Agroecosystems

NASA Astrophysics Data System (ADS)

Williard, K.; Swanberg, S.; Schoonover, J.

2013-05-01

Intensive cropping systems of corn (Zea Mays L.) and soybeans (Glycine max) are commonly leaky systems with respect to nitrogen (N). Reactive N outputs from agroecosystems can contribute to eutrophication and hypoxic zones in downstream water bodies and greenhouse gas (N2O) emissions. Incorporating cover crops into temperate agroecosystem rotations has been promoted as a tool to increase nitrogen use efficiency and thus limit reactive N outputs to the environment. Our objective was determine how cereal rye (Secale cereal L.) and annual ryegrass (Lolium multiflorum) cover crops impact nutrient and soil water dynamics in an intensive corn and soybean cropping rotation in central Illinois. Cover crops were planted in mid to late October and terminated in early April prior to corn or soybean planting. In the spring just prior to cover crop termination, soil moisture levels were lower in the cover crop plots compared to no cover plots. This can be a concern for the subsequent crop in relatively dry years, which the Midwestern United States experienced in 2012. No cover plots had greater nutrient leaching below the rooting zone compared to cover crop areas, as expected. The cover crops were likely scavenging nutrients during the fall and early spring and should provide nutrients to the subsequent crop via decomposition and mineralization of the cover crop residue. Over the long term, cover crop systems should produce greater inputs and cycling of carbon and N, increasing the productivity of crops due to the long-term accumulation of soil organic matter. This study demonstrates that there may be short term trade-offs in reduced soil moisture levels that should be considered alongside the long term nutrient scavenging and recycling benefits of cover crops.

Modelling potential production of macroalgae farms in UK and Dutch coastal waters

NASA Astrophysics Data System (ADS)

van der Molen, Johan; Ruardij, Piet; Mooney, Karen; Kerrison, Philip; O'Connor, Nessa E.; Gorman, Emma; Timmermans, Klaas; Wright, Serena; Kelly, Maeve; Hughes, Adam D.; Capuzzo, Elisa

2018-02-01

There is increasing interest in macroalgae farming in European waters for a range of applications, including food, chemical extraction for biofuel production. This study uses a 3-D numerical model of hydrodynamics and biogeochemistry to investigate potential production and environmental effects of macroalgae farming in UK and Dutch coastal waters. The model included four experimental farms in different coastal settings in Strangford Lough (Northern Ireland), in Sound of Kerrera and Lynn of Lorne (north-west Scotland) and in the Rhine plume (the Netherlands), as well as a hypothetical large-scale farm off the UK north Norfolk coast. The model could not detect significant changes in biogeochemistry and plankton dynamics at any of the farm sites averaged over the farming season. The results showed a range of macroalgae growth behaviours in response to simulated environmental conditions. These were then compared with in situ observations where available, showing good correspondence for some farms and less good correspondence for others. At the most basic level, macroalgae production depended on prevailing nutrient concentrations and light conditions, with higher levels of both resulting in higher macroalgae production. It is shown that under non-elevated and interannually varying winter nutrient conditions, farming success was modulated by the timings of the onset of increasing nutrient concentrations in autumn and nutrient drawdown in spring. Macroalgae carbohydrate content also depended on nutrient concentrations, with higher nutrient concentrations leading to lower carbohydrate content at harvest. This will reduce the energy density of the crop and thus affect its suitability for conversion into biofuel. For the hypothetical large-scale macroalgae farm off the UK north Norfolk coast, the model suggested high, stable farm yields of macroalgae from year to year with substantial carbohydrate content and limited environmental effects.

Effects of irradiation intensity and pH on nutrients release and solids destruction of waste activated sludge using the microwave-enhanced advanced oxidation process.

PubMed

Chan, W I; Liao, P H; Lo, K V

2010-11-01

Using the microwave-enhanced advanced oxidation process (MW/H2O2-AOP), the pH and irradiation intensity on waste activated sludge samples were investigated to provide insight to the athermal effects on nutrients release, solids destruction, particle size distribution and dewaterability, and to demonstrate their interrelationships. Carbonaceous matters and nutrients released into solution depended on the irradiation intensity and time. Higher irradiation levels tended to be more effective in the solubilization of nutrients and had more pronounced effects in the dewaterability of sludge. In terms of particle size distribution, detectable particles increased in size for treatments in acidic conditions, while the dewaterability of treated sludge was improved. In treatments under neutral and alkaline conditions, the particle size range increased, with more small particles formed, thereby significantly deteriorating the dewaterability of sludge treated in alkaline conditions. The best results for the solubilization of nutrients were in alkaline conditions with high irradiation power, but dewaterability of the sludge was compromised. Sludge treatment with the MW/H2O2-AOP in acidic conditions with high irradiation power yielded the best dewaterable sludge and significant nutrient solubilization; therefore, it is the recommended treatment condition for activated sludge.

Connecting the Dots: Responses of Coastal Ecosystems to Changing Nutrient Concentrations

PubMed Central

2011-01-01

Empirical relationships between phytoplankton biomass and nutrient concentrations established across a wide range of different ecosystems constitute fundamental quantitative tools for predicting effects of nutrient management plans. Nutrient management plans based on such relationships, mostly established over trends of increasing rather than decreasing nutrient concentrations, assume full reversibility of coastal eutrophication. Monitoring data from 28 ecosystems located in four well-studied regions were analyzed to study the generality of chlorophyll a versus nutrient relationships and their applicability for ecosystem management. We demonstrate significant differences across regions as well as between specific coastal ecosystems within regions in the response of chlorophyll a to changing nitrogen concentrations. We also show that the chlorophyll a versus nitrogen relationships over time constitute convoluted trajectories rather than simple unique relationships. The ratio of chlorophyll a to total nitrogen almost doubled over the last 30–40 years across all regions. The uniformity of these trends, or shifting baselines, suggest they may result from large-scale changes, possibly associated with global climate change and increasing human stress on coastal ecosystems. Ecosystem management must, therefore, develop adaptation strategies to face shifting baselines and maintain ecosystem services at a sustainable level rather than striving to restore an ecosystem state of the past. PMID:21958109

Optimisation modelling to assess cost of dietary improvement in remote Aboriginal Australia.

PubMed

Brimblecombe, Julie; Ferguson, Megan; Liberato, Selma C; O'Dea, Kerin; Riley, Malcolm

2013-01-01

The cost and dietary choices required to fulfil nutrient recommendations defined nationally, need investigation, particularly for disadvantaged populations. We used optimisation modelling to examine the dietary change required to achieve nutrient requirements at minimum cost for an Aboriginal population in remote Australia, using where possible minimally-processed whole foods. A twelve month cross-section of population-level purchased food, food price and nutrient content data was used as the baseline. Relative amounts from 34 food group categories were varied to achieve specific energy and nutrient density goals at minimum cost while meeting model constraints intended to minimise deviation from the purchased diet. Simultaneous achievement of all nutrient goals was not feasible. The two most successful models (A & B) met all nutrient targets except sodium (146.2% and 148.9% of the respective target) and saturated fat (12.0% and 11.7% of energy). Model A was achieved with 3.2% lower cost than the baseline diet (which cost approximately AUD$13.01/person/day) and Model B at 7.8% lower cost but with a reduction in energy of 4.4%. Both models required very large reductions in sugar sweetened beverages (-90%) and refined cereals (-90%) and an approximate four-fold increase in vegetables, fruit, dairy foods, eggs, fish and seafood, and wholegrain cereals. This modelling approach suggested population level dietary recommendations at minimal cost based on the baseline purchased diet. Large shifts in diet in remote Aboriginal Australian populations are needed to achieve national nutrient targets. The modeling approach used was not able to meet all nutrient targets at less than current food expenditure.

ASSESSING THE IMPACTS OF SALINITY AND NUTRIENT ...

EPA Pesticide Factsheets

Healthy seagrass beds were once found throughout the shallow areas of Narragansett Bay, R.I. but have disappeared due to infilling, pollution and disease. In Greenwich Bay, a highly developed embayment within Narragansett Bay, Ruppia maritima has colonized an area on the northern shore once dominated by Zostera marina. This area is sandy, which may allow groundwater seepage. Ruppia is extremely salinity tolerant, and may also be more nutrient tolerant than Zostera. A six week microcosm experiment at two salinity (20 and 30 ppt) and 4 nutrient (0, 5, 10, and 30 µM inorganic N) levels to test their relative tolerance was conducted in 2014. Treatments were renewed daily to simulate tidal flushing and the exposure water was dosed with 15N for the first week of the experiment. At the end of the experiment, the plants were weighed and measured, and dried for later isotopic analysis. In the first experiment, Ruppia had significant structural responses to both nutrients and salinity; there was a slight decline in root weight and a decrease in the total number of shoots with increasing nutrients. Average Ruppia blade length decreased with increasing nutrients and this decrease was more evident at 30 ppt. In contrast, Zostera had no significant structural differences. For both species, there were no differences in shoot or root/rhizome weights in any treatment, nor were there differences in isotopic results due to salinity. However, δ15N in the tissue increase

Drug-nutrient interactions.

PubMed

Chan, Lingtak-Neander

2013-07-01

Drug-nutrient interactions are defined as physical, chemical, physiologic, or pathophysiologic relationships between a drug and a nutrient. The causes of most clinically significant drug-nutrient interactions are usually multifactorial. Failure to identify and properly manage drug-nutrient interactions can lead to very serious consequences and have a negative impact on patient outcomes. Nevertheless, with thorough review and assessment of the patient's history and treatment regimens and a carefully executed management strategy, adverse events associated with drug-nutrient interactions can be prevented. Based on the physiologic sequence of events after a drug or a nutrient has entered the body and the mechanism of interactions, drug-nutrient interactions can be categorized into 4 main types. Each type of interaction can be managed using similar strategies. The existing data that guide the clinical management of most drug-nutrient interactions are mostly anecdotal experience, uncontrolled observations, and opinions, whereas the science in understanding the mechanism of drug-nutrient interactions remains limited. The challenge for researchers and clinicians is to increase both basic and higher level clinical research in this field to bridge the gap between the science and practice. The research should aim to establish a better understanding of the function, regulation, and substrate specificity of the nutrient-related enzymes and transport proteins present in the gastrointestinal tract, as well as assess how the incidence and management of drug-nutrient interactions can be affected by sex, ethnicity, environmental factors, and genetic polymorphisms. This knowledge can help us develop a true personalized medicine approach in the prevention and management of drug-nutrient interactions.

Depletion and Redistribution of Soil Nutrients in Response to Wind Erosion in Desert Grasslands of the Southwestern United States

NASA Astrophysics Data System (ADS)

Li, J.; Okin, G.; Hartman, L.; Epstein, H.

2005-12-01

Wind is a key abiotic factor that determines the spatial distribution of soil nutrients in arid grasslands with large unvegetated gaps, such as those found in the southwestern US. On the landscape scale, basic relationships such as wind erosion rate vs. vegetative cover, and soil nutrient removal rate vs. vegetative cover have not yet been extensively studied. In a series of experiments conducted in the Jornada Experimental Range near Las Cruces, New Mexico, we have examined these relationships to determine the impact of wind erosion and dust emission on pools of soil nutrients. In the experiments, varying levels of cover were achieved by vegetation removal on 25 m x 50 m plots. Intense surface soil sampling was conducted to monitor spatial distribution of soil nutrients. Large numbers of aeolian sediment samplers were installed to obtain estimates of vertical and horizontal dust flux. Available data from one wind erosion season show that: 1) total organic C (TOC) and total N (TN) content in the windblown sediment collected at the height of 1 m were 2.2 to 7.2 times larger than those of nutrients in the surface soil (enrichment ratio); 2) enrichment ratio generally increases with the increase of vegetative cover, indicating biotic processes continually add nutrients to surface soil in high-cover treatments, while nutrients are depleted in low-cover treatments; 3) average horizontal mass flux is 12 times larger in the bare plot than in the control plot, indicating the extreme importance of vegetative cover in protecting soil nutrient loss caused by wind erosion; 4) detectable soil nutrient depletion happened within one windy season in plots with vegetation removal, especially for TOC and TN, reflecting the importance of biotic processes in maintaining nutrient pools in the surface soil; and, 5) after only a single windy season, wind erosion can significantly alter the spatial pattern of soil nutrients.

Basal area growth of sugar maple in relation to acid deposition, stand health, and soil nutrients.

PubMed

Duchesne, Louis; Ouimet, Rock; Houle, Daniel

2002-01-01

Previous studies have shown in noncalcareous soils that acid deposition may have increased soil leaching of basic cations above the input rate from soil weathering and atmospheric depositions. This phenomenon may have increased soil acidity levels, and, as a consequence, may have reduced the availability of these essential nutrients for forest growth. Fourteen plots of the Forest Ecosystem Research and Monitoring Network in Québec were used to examine the relation between post-industrial growth trends of sugar maple (Acer saccharum Marsh.) and acid deposition (N and S), stand decline rate, and soil exchangeable nutrient concentrations. Atmospheric N and S deposition and soil exchangeable acidity were positively associated with stand decline rate, and negatively with the average tree basal area increment trend. The growth rate reduction reached on average 17% in declining stands compared with healthy ones. The results showed a significant sugar maple growth rate reduction since 1960 on acid soils. The appearance of the forest decline phenomenon in Québec can be attributed, at least partially, to soil acidification and acid deposition levels.

A novel nutrient sensing mechanism underlies substrate-induced regulation of monocarboxylate transporter-1

PubMed Central

Priyamvada, Shubha; Kumar, Anoop; Natarajan, Arivarasu A.; Gill, Ravinder K.; Alrefai, Waddah A.; Dudeja, Pradeep K.

2012-01-01

Monocarboxylate transporter isoform-1 (MCT1) plays an important role in the absorption of short-chain fatty acids (SCFAs) in the colon. Butyrate, a major SCFA, serves as the primary energy source for the colonic mucosa, maintains epithelial integrity, and ameliorates intestinal inflammation. Previous studies have shown substrate (butyrate)-induced upregulation of MCT1 expression and function via transcriptional mechanisms. The present studies provide evidence that short-term MCT1 regulation by substrates could be mediated via a novel nutrient sensing mechanism. Short-term regulation of MCT1 by butyrate was examined in vitro in human intestinal C2BBe1 and rat intestinal IEC-6 cells and ex vivo in rat intestinal mucosa. Effects of pectin feeding on MCT1, in vivo, were determined in rat model. Butyrate treatment (30–120 min) of C2BBe1 cells increased MCT1 function {p-(chloromercuri) benzene sulfonate (PCMBS)-sensitive [14C]butyrate uptake} in a pertussis toxin-sensitive manner. The effects were associated with decreased intracellular cAMP levels, increased Vmax of butyrate uptake, and GPR109A-dependent increase in apical membrane MCT1 level. Nicotinic acid, an agonist for the SCFA receptor GPR109A, also increased MCT1 function and decreased intracellular cAMP. Pectin feeding increased apical membrane MCT1 levels and nicotinate-induced transepithelial butyrate flux in rat colon. Our data provide strong evidence for substrate-induced enhancement of MCT1 surface expression and function via a novel nutrient sensing mechanism involving GPR109A as a SCFA sensor. PMID:22982338

A comparison of algal, macroinvertebrate, and fish assemblage indices for assessing low-level nutrient enrichment in wadeable Ozark streams

USGS Publications Warehouse

Justus, B.G.; Petersen, J.C.; Femmer, S.R.; Davis, J.V.; Wallace, J.E.

2010-01-01

Biotic indices for algae, macroinvertebrates, and fish assemblages can be effective for monitoring stream enrichment, but little is known regarding the value of the three assemblages for detecting perturbance as a consequence of low-level nutrient enrichment. In the summer of 2006, we collected nutrient and biotic samples from 30 wadeable Ozark streams that spanned a nutrient-concentration gradient from reference to moderately enriched conditions. Seventy-three algal metrics, 62 macroinvertebrate metrics, and 60 fish metrics were evaluated for each of the three biotic indices. After a group of candidate metrics had been identified with multivariate analysis, correlation procedures and scatter plots were used to identify the four metrics having strongest relations to a nutrient index calculated from log transformed and normalized total nitrogen and total phosphorus concentrations. The four metrics selected for each of the three biotic indices were: algae-the relative abundance of most tolerant diatoms, the combined relative abundance of three species of Cymbella, mesosaprobic algae percent taxa richness, and the relative abundance of diatoms that are obligate nitrogen heterotrophs; macroinvertebrate-the relative abundance of intolerant organisms, Baetidae relative abundance, moderately tolerant taxa richness, and insect biomass; fish-herbivore and detritivore taxa richness, pool species relative abundance, fish catch per unit effort, and black bass (Micropterus spp.) relative abundance. All three biotic indices were negatively correlated to nutrient concentrations but the algal index had a higher correlation (rho = -0.89) than did the macroinvertebrate and fish indices (rho = -0.63 and -0.58, respectively). Biotic index scores were lowest and nutrient concentrations were highest for streams with basins having the highest poultry and cattle production. Because of the availability of litter for fertilizer and associated increases in grass and hay production, cattle feeding capacity increases with poultry production. Studies are needed that address the synergistic effect of poultry and cattle production on Ozark streams in high production areas before ecological risks can be adequately addressed.

Increasing Plant Based Foods or Dairy Foods Differentially Affects Nutrient Intakes: Dietary Scenarios Using NHANES 2007–2010

PubMed Central

Cifelli, Christopher J.; Houchins, Jenny A.; Demmer, Elieke; Fulgoni, Victor L.

2016-01-01

Diets rich in plant foods and lower in animal-based products have garnered increased attention among researchers, dietitians and health professionals in recent years for their potential to, not only improve health, but also to lessen the environmental impact. However, the potential effects of increasing plant-based foods at the expense of animal-based foods on macro- and micronutrient nutrient adequacy in the U.S. diet is unknown. In addition, dairy foods are consistently under consumed, thus the impact of increased dairy on nutrient adequacy is important to measure. Accordingly, the objective of this study was to use national survey data to model three different dietary scenarios to assess the effects of increasing plant-based foods or dairy foods on macronutrient intake and nutrient adequacy. Data from the National Health and Nutrition Examination Survey (NHANES) 2007–2010 for persons two years and older (n = 17,387) were used in all the analyses. Comparisons were made of usual intake of macronutrients and shortfall nutrients of three dietary scenarios that increased intakes by 100%: (i) plant-based foods; (ii) protein-rich plant-based foods (i.e., legumes, nuts, seeds, soy); and (iii) milk, cheese and yogurt. Scenarios (i) and (ii) had commensurate reductions in animal product intake. In both children (2–18 years) and adults (≥19 years), the percent not meeting the Estimated Average Requirement (EAR) decreased for vitamin C, magnesium, vitamin E, folate and iron when plant-based foods were increased. However the percent not meeting the EAR increased for calcium, protein, vitamin A, and vitamin D in this scenario. Doubling protein-rich plant-based foods had no effect on nutrient intake because they were consumed in very low quantities in the baseline diet. The dairy model reduced the percent not meeting the EAR for calcium, vitamin A, vitamin D, magnesium, and protein, while sodium and saturated fat levels increased. Our modeling shows that increasing plant-based foods could lead to unintended dietary outcomes without simultaneous changes in the types and amounts of plant foods currently consumed. Increasing dairy foods, which are currently under-consumed, could assist in improving the intakes of many nutrients of concern. PMID:27409633

Nutrient digestibility of broiler feeds containing different levels of variously processed rice bran stored for different periods.

PubMed

Mujahid, A; Asif, M; ul Haq, I; Abdullah, M; Gilani, A H

2003-09-01

Nutrient digestibility of broiler feeds containing different levels of variously processed rice bran stored for varying periods was determined. A total of 444 Hubbard male chicks were used to conduct four trials. Each trial was carried out on 111 chicks to determine digestibility of 36 different feeds. Chicks of 5 wk age were fed feeds containing raw, roasted, and extruded rice bran treated with antioxidant, Bianox Dry (0, 125, 250 g/ton), stored for a periods of 0, 4, 8, and 12 mo and used at levels of 0, 10, 20, and 30% in feeds. Digestibility coefficients for fat and fiber of feeds were determined. Increasing storage periods of rice bran significantly reduced the fat digestibility of feed, whereas no difference in fiber digestibility was observed. Processing of rice bran by extrusion cooking significantly increased digestibility of fat even used at higher levels in broiler feeds. Interaction of storage, processing, and levels was significant for fat digestibility. Treatments of rice bran by different levels of antioxidant had no effect on digestibility of fat and fiber when incorporated in broiler feed.

Climate warming and agricultural stressors interact to determine stream periphyton community composition.

PubMed

Piggott, Jeremy J; Salis, Romana K; Lear, Gavin; Townsend, Colin R; Matthaei, Christoph D

2015-01-01

Lack of knowledge about how the various drivers of global climate change will interact with multiple stressors already affecting ecosystems is the basis for great uncertainty in projections of future biological change. Despite concerns about the impacts of changes in land use, eutrophication and climate warming in running waters, the interactive effects of these stressors on stream periphyton are largely unknown. We manipulated nutrients (simulating agricultural runoff), deposited fine sediment (simulating agricultural erosion) (two levels each) and water temperature (eight levels, 0-6 °C above ambient) simultaneously in 128 streamside mesocosms. Our aim was to determine the individual and combined effects of the three stressors on the algal and bacterial constituents of the periphyton. All three stressors had pervasive individual effects, but in combination frequently produced synergisms at the population level and antagonisms at the community level. Depending on sediment and nutrient conditions, the effect of raised temperature frequently produced contrasting response patterns, with stronger or opposing effects when one or both stressors were augmented. Thus, warming tended to interact negatively with nutrients or sediment by weakening or reversing positive temperature effects or strengthening negative ones. Five classes of algal growth morphology were all affected in complex ways by raised temperature, suggesting that these measures may prove unreliable in biomonitoring programs in a warming climate. The evenness and diversity of the most abundant bacterial taxa increased with temperature at ambient but not with enriched nutrient levels, indicating that warming coupled with nutrient limitation may lead to a more evenly distributed bacterial community as temperatures rise. Freshwater management decisions that seek to avoid or mitigate the negative effects of agricultural land use on stream periphyton should be informed by knowledge of the interactive effects of multiple stressors in a warming climate. © 2014 John Wiley & Sons Ltd.

Analysis of nutrients in the surface waters of the Georgia-Florida Coastal Plain study unit, 1970-91

USGS Publications Warehouse

Ham, L.K.; Hatzell, H.H.

1996-01-01

During the early phase of the Georgia-Florida National Water Quality Assessment study, existing information on nutrients was compiled and analyzed in order to evaluate the nutrient concentrations within the 61,545 square mile study unit. Evaluation of the nutrient concentrations collected at surface- water sites between October 1, 1970, and September 30,1991, utilized the environmental characteristics of land resource provinces, land use, and nonpoint and point-source discharges within the study unit. Long-term trends were investigated to determine the temporal distribution of nutrient concentrations. In order to determine a level of concern for nutrient concentrations, the U.S. Environmental Protection Agency (USEPA) guidelines were used-(1) for nitrate concentrations, the maximum contaminant level in public-drinking water supplies (10 mg/L); (2) for ammonia concentrations, the chronic exposure of aquatic organisms to un-ionized ammonia (2.1 mg/L); (3) for total-phosphorus concentrations, the recommended concentration in flowing water to discourage excessive growth of aquatic plants (0.1 mg/L); and (4) for kjeldahl concentrations, however, no guidelines were available. For sites within the 10 major river basins, median nutrient concentrations were generally below USEPA guidelines, except for total-phosphorus concentrations where 45 percent of the medians exceeded the guideline. The only median ammonia concentration that exceeded the guideline occurred at the Swift Creek site (3.4 mg/L), in the Suwannee River basin, perhaps due to wastewater discharges. For all sites within the Withlacoochee, Aucilla, and St. Marys River basins, median concentrations of nitrate, ammonia, and total phosphorus were below the USEPA guidelines. Nutrient data at each monitoring site within each major basin were aggregated for comparisons of median nutrient concentrations among major basins. The Ochlockonee and Hillsborough River basins had the highest median nutrient concentrations, the Aucilla River basin had the lowest. Median concentrations of nitrate and ammonia among all major basins were below USEPA guidelines. The median total-phosphorus concentrations for the following river basins exceeded the USEPA guideline-Hillsborough, St. Johns, Suwannee, Ochlockonee, Satilla, Altamaha, and Ogeechee. Although nutrient concentrations within the study unit were low, long-term increasing trends were found in all four nutrients. All 18 study-unit wide nitrate trends had increasing slopes ranging from less than 0.01 to 0.07 (mg/L)/yr. The range in slope for the 13 ammonia trends was -0.03 to 0.01 (mg/L)/yr with 6 increasing trends in the northern part of the study unit. Of the 17 total-phosphorus trends found in the study unit, 10 were found at sites where the median concentration exceeded the USEPA guideline. At these 10 sites, 4 sites had increasing trends with slopes ranging from less than 0.01 to 0.07 (mg/L)/yr, 5 sites had decreasing trends with slopes ranging from -0.01 to -0.24 (mg/L)/yr, and one site showed a seasonal concentration trend. Median nutrient concentrations were significantly different among the four land resource provinces-Southern Piedmont, Southern Coastal Plain, Coastal Flatwoods, and Central Florida Ridge. As a result, nutrient concentrations among basins with similar nutrient inputs but located within different land resource provinces are not expected to be the same due to differences in the combination of factors such as soil permeability, runoff rates, and stream channel slopes. This concept is an important consideration in designing a surface-water quality network within the study area. For the most part, the Coastal Flatwoods showed the lowest median nutrient concentrations and the Southern Coastal Plain had the highest median nutrient concentrations. Lower median nitrate concentrations in surface-water basins were associated with the forest/wetland land-use category and higher median concentrations of nitrate and ammonia with

Nutrient uplift in a cyclonic eddy increases diversity, primary productivity and iron demand of microbial communities relative to a western boundary current.

PubMed

Doblin, Martina A; Petrou, Katherina; Sinutok, Sutinee; Seymour, Justin R; Messer, Lauren F; Brown, Mark V; Norman, Louiza; Everett, Jason D; McInnes, Allison S; Ralph, Peter J; Thompson, Peter A; Hassler, Christel S

2016-01-01

The intensification of western boundary currents in the global ocean will potentially influence meso-scale eddy generation, and redistribute microbes and their associated ecological and biogeochemical functions. To understand eddy-induced changes in microbial community composition as well as how they control growth, we targeted the East Australian Current (EAC) region to sample microbes in a cyclonic (cold-core) eddy (CCE) and the adjacent EAC. Phototrophic and diazotrophic microbes were more diverse (2-10 times greater Shannon index) in the CCE relative to the EAC, and the cell size distribution in the CCE was dominated (67%) by larger micro-plankton [Formula: see text], as opposed to pico- and nano-sized cells in the EAC. Nutrient addition experiments determined that nitrogen was the principal nutrient limiting growth in the EAC, while iron was a secondary limiting nutrient in the CCE. Among the diazotrophic community, heterotrophic NifH gene sequences dominated in the EAC and were attributable to members of the gamma-, beta-, and delta-proteobacteria, while the CCE contained both phototrophic and heterotrophic diazotrophs, including Trichodesmium, UCYN-A and gamma-proteobacteria. Daily sampling of incubation bottles following nutrient amendment captured a cascade of effects at the cellular, population and community level, indicating taxon-specific differences in the speed of response of microbes to nutrient supply. Nitrogen addition to the CCE community increased picoeukaryote chlorophyll a quotas within 24 h, suggesting that nutrient uplift by eddies causes a 'greening' effect as well as an increase in phytoplankton biomass. After three days in both the EAC and CCE, diatoms increased in abundance with macronutrient (N, P, Si) and iron amendment, whereas haptophytes and phototrophic dinoflagellates declined. Our results indicate that cyclonic eddies increase delivery of nitrogen to the upper ocean to potentially mitigate the negative consequences of increased stratification due to ocean warming, but also increase the biological demand for iron that is necessary to sustain the growth of large-celled phototrophs and potentially support the diversity of diazotrophs over longer time-scales.

Element interactions limit soil carbon storage

PubMed Central

van Groenigen, Kees-Jan; Six, Johan; Hungate, Bruce A.; de Graaff, Marie-Anne; van Breemen, Nico; van Kessel, Chris

2006-01-01

Rising levels of atmospheric CO2 are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO2 emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO2 only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO2 only enhances N2 fixation, the major natural process providing soil N input, when other nutrients (e.g., phosphorus, molybdenum, and potassium) are added. Hence, soil C sequestration under elevated CO2 is constrained both directly by N availability and indirectly by nutrients needed to support N2 fixation. PMID:16614072

Reducing environmental risk of excessively fertilized soils and improving cucumber growth by Caragana microphylla-straw compost application in long-term continuous cropping systems.

PubMed

Tian, Yongqiang; Wang, Qing; Zhang, Weihua; Gao, Lihong

2016-02-15

Continuous cropping is a common agricultural practice in the word. In China, farmers often apply excessive fertilizers to fields in an attempt to maintain yields in continuous cropping systems. However, this practice often results in high nutrient concentrations in soils, nutrient pollution in leaching water and more crop disease. Here, we investigated 8 different soils from continuously cropped cucumbers in Northern China that grouped into those with extremely high nutrient levels (EHNL) and those with lower nutrient levels (LNL). All soils were treated with Caragana microphylla-straw (CMS) compost addition, and then were used to measure soil physiochemical and microbial properties, leaching water quality, plant root growth and cucumber fruit yield. In general, the EHNL-soil showed higher nitrate, phosphorus and potassium concentrations in the leaching water compared to the LNL-soil. However, the CMS compost application increased soil nutrient and water holding capacities, total microbial biomass (bacteria and fungi), root length, plant biomass and fruit yields, but decreased nutrient concentrations in the leaching water from the EHNL-soil. In addition, the CMS compost decreased the number of Fusarium oxysporum f. sp. cucumerinum in soils with very high concentration of mineral nitrogen. Our results infer that CMS compost application was an effective method for reducing environmental risk of excessively fertilized soils. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of inclusion levels of pelleted silvergrass (Miscanthus sinensis Andress.) in the diet on digestibility, chewing activity, ruminal fermentation and blood metabolites in breeding Japanese Black cows.

PubMed

Asano, Keigo; Ishida, Miho; Ishida, Motohiko

2017-03-01

To examine the effects of inclusion levels of pelleted silvergrass (PS) in the diet on digestibility, ruminal fermentation and nutrient status of breeding Japanese Black cows, four cows were allotted to a 4 × 4 Latin square design experiment. Treatments were control fed a diet consisting of 89.4% Sudangrass hay and 10.6% soybean meal on a dry matter (DM) basis, and PS18, PS27 and PS45 fed the diet replaced with 18%, 27% and 45% of control with PS, respectively. The total digestible nutrients (TDN) content of PS was 45.6% on a DM basis. The TDN intakes were significantly decreased by increasing PS level in the diet (P < 0.05), but were higher than the TDN requirement of maintenance cows in all treatments. The total chewing time was decreased significantly by increasing PS level in the diets (P < 0.05). However, the pH and concentration of volatile fatty acid in the ruminal fluid and serum metabolite concentrations were not significantly different among the treatments. The results suggested that including PS up to 45% in the diet did not have adverse effects on the ruminal fermentation and nutrient status in breeding Japanese Black cows at the maintenance stage. © 2016 Japanese Society of Animal Science.

Transcriptional and Physiological Responses to Nutrient Loading on Toxin Formation and Photosynthesis in Microcystis Aeruginosa FACHB-905

PubMed Central

Peng, Guotao; Lin, Sijie; Fan, Zhengqiu; Wang, Xiangrong

2017-01-01

An important goal of understanding harmful algae blooms is to determine how environmental factors affect the growth and toxin formation of toxin-producing species. In this study, we investigated the transcriptional responses of toxin formation gene (mcyB) and key photosynthesis genes (psaB, psbD and rbcL) of Microcystis aeruginosa FACHB-905 in different nutrient loading conditions using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR). Three physio-biochemical parameters (malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH)) were also evaluated to provide insight into the physiological responses of Microcystis cells. We observed an upregulation of mcyB gene in nutrient-deficient conditions, especially in nitrogen (N) limitation condition, and the transcript abundance declined after the nutrient were resupplied. Differently, high transcription levels were seen in phosphorus (P) deficient treatments for key photosynthesis genes throughout the culture period, while those in N-deficient cells varied with time, suggesting an adaptive regulation of Microsystis cells to nutrient stress. Increased contents of antioxidant enzymes (SOD and GSH) were seen in both N and P-deficient conditions, suggesting the presence of excess amount of free radical generation caused by nutrient stress. The amount of SOD and GSH continued to increase even after the nutrient was reintroduced and a strong correlation was seen between the MDA and enzyme activities, indicating the robust effort of rebalancing the redox system in Microcystis cells. Based on these transcriptional and physiological responses of M. aeruginosa to nutrient loading, these results could provide more insight into Microcystis blooms management and toxin formation regulation. PMID:28513574

Transcriptional and Physiological Responses to Nutrient Loading on Toxin Formation and Photosynthesis in Microcystis Aeruginosa FACHB-905.

PubMed

Peng, Guotao; Lin, Sijie; Fan, Zhengqiu; Wang, Xiangrong

2017-05-17

An important goal of understanding harmful algae blooms is to determine how environmental factors affect the growth and toxin formation of toxin-producing species. In this study, we investigated the transcriptional responses of toxin formation gene ( mcyB ) and key photosynthesis genes ( psaB , psbD and rbcL) of Microcystis aeruginosa FACHB-905 in different nutrient loading conditions using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR). Three physio-biochemical parameters (malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH)) were also evaluated to provide insight into the physiological responses of Microcystis cells. We observed an upregulation of mcyB gene in nutrient-deficient conditions, especially in nitrogen (N) limitation condition, and the transcript abundance declined after the nutrient were resupplied. Differently, high transcription levels were seen in phosphorus (P) deficient treatments for key photosynthesis genes throughout the culture period, while those in N-deficient cells varied with time, suggesting an adaptive regulation of Microsystis cells to nutrient stress. Increased contents of antioxidant enzymes (SOD and GSH) were seen in both N and P-deficient conditions, suggesting the presence of excess amount of free radical generation caused by nutrient stress. The amount of SOD and GSH continued to increase even after the nutrient was reintroduced and a strong correlation was seen between the MDA and enzyme activities, indicating the robust effort of rebalancing the redox system in Microcystis cells. Based on these transcriptional and physiological responses of M. aeruginosa to nutrient loading, these results could provide more insight into Microcystis blooms management and toxin formation regulation.

Nutrient availability and phytoplankton nutrient limitation across a gradient of atmospheric nitrogen deposition

USGS Publications Warehouse

Elser, J.J.; Kyle, M.; Steuer, L.; Nydick, K.R.; Baron, Jill S.

2009-01-01

Atmospheric nitrogen (N) deposition to lakes and watersheds has been increasing steadily due to various anthropogenic activities. Because such anthropogenic N is widely distributed, even lakes relatively removed from direct human disturbance are potentially impacted. However, the effects of increased atmospheric N deposition on lakes are not well documented, We examined phytoplankton biomass, the absolute and relative abundance of limiting nutrients (N and phosphorus [P]), and phytoplankton nutrient limitation in alpine lakes of the Rocky Mountains of Colorado (USA) receiving elevated (>6 kg N??ha-1??yr-1) or low (<2 kg N??ha-1??yr-1) levels of atmospheric N deposition. Highdeposition lakes had higher NO3-N and total N concentrations and higher total N : total P ratios. Concentrations of chlorophyll and seston carbon (C) were 2-2.5 times higher in highdeposition relative to low-deposition lakes, while high-deposition lakes also had higher seston C:N and C:P (but not N:P) ratios. Short-term enrichment bioassays indicated a qualitative shift in the nature of phytoplankton nutrient limitation due to N deposition, as highdeposition lakes had an increased frequency of primary P limitation and a decreased frequency and magnitude of response to N and to combined N and P enrichment. Thus elevated atmospheric N deposition appears to have shifted nutrient supply from a relatively balanced but predominantly N-deficient regime to a more consistently P-limited regime in Colorado alpine lakes. This adds to accumulating evidence that sustained N deposition may have important effects on lake phytoplankton communities and plankton-based food webs by shifting the quantitative and qualitative nature of nutrient limitation. ?? 2009 by the Ecological Society of America.

A global database of nitrogen and phosphorus excretion rates of aquatic animals

DOE PAGES

Vanni, Michael J.; McIntyre, Peter B.; Allen, Dennis; ...

2017-03-06

Though their importance varies greatly among species and ecosystems, animals can be important in modulating ecosystem-level nutrient cycling. Nutrient cycling rates of individual animals represent valuable data for testing the predictions of important frameworks such as the Metabolic Theory of Ecology (MTE) and ecological stoichiometry (ES). They also represent an important set of functional traits that may reflect both environmental and phylogenetic influences. Over the past two decades, studies of animal-mediated nutrient cycling have increased dramatically, especially in aquatic ecosystems. Here we present a global compilation of aquatic animal nutrient excretion rates. The dataset includes 10,534 observations from freshwater andmore » marine animals of N and/or P excretion rates. Furthermore, these observations represent 491 species, including most aquatic phyla. Coverage varies greatly among phyla and other taxonomic levels. The dataset includes information on animal body size, ambient temperature, taxonomic affiliations, and animal body N:P. We used this data set to test predictions of MTE and ES, as described in Vanni and McIntyre (2016; Ecology DOI: 10.1002/ecy.1582).« less

A global database of nitrogen and phosphorus excretion rates of aquatic animals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanni, Michael J.; McIntyre, Peter B.; Allen, Dennis

Though their importance varies greatly among species and ecosystems, animals can be important in modulating ecosystem-level nutrient cycling. Nutrient cycling rates of individual animals represent valuable data for testing the predictions of important frameworks such as the Metabolic Theory of Ecology (MTE) and ecological stoichiometry (ES). They also represent an important set of functional traits that may reflect both environmental and phylogenetic influences. Over the past two decades, studies of animal-mediated nutrient cycling have increased dramatically, especially in aquatic ecosystems. Here we present a global compilation of aquatic animal nutrient excretion rates. The dataset includes 10,534 observations from freshwater andmore » marine animals of N and/or P excretion rates. Furthermore, these observations represent 491 species, including most aquatic phyla. Coverage varies greatly among phyla and other taxonomic levels. The dataset includes information on animal body size, ambient temperature, taxonomic affiliations, and animal body N:P. We used this data set to test predictions of MTE and ES, as described in Vanni and McIntyre (2016; Ecology DOI: 10.1002/ecy.1582).« less

Landscape influence on soil carbon and nutrient levels

USDA-ARS?s Scientific Manuscript database

Past runoff, erosion, and management practices influence nutrient levels on the landscape. These starting levels affect future nutrient transport due to runoff, erosion, and leaching events. The purpose of this study was to examine closed-depression landscape effects on surface soil organic matter, ...

Growth, biomass allocation and nutrient use efficiency in Cladium jamaicense and Typha domingensis as affected by phosphorus and oxygen availability

USGS Publications Warehouse

Lorenzen, B.; Brix, H.; Mendelssohn, I.A.; McKee, K.L.; Miao, S.L.

2001-01-01

The effects of phosphorus (P) and oxygen availability on growth, biomass allocation and nutrient use efficiency in Cladium jamaicense Crantz and Typha domingensis Pers. were studied in a growth facility equipped with steady-state hydroponic rhizotrons. The treatments included four P concentrations (10, 40, 80 and 500 ??g I-1) and two oxygen concentration (8.0 and <0.5 mg O2 I-1) in the culture solutions. In Cladium, no clear relationship was found between P availability and growth rate (19-37 mg g-1 d-1), the above to below ground biomass ratio (A/B) (mean = 4.6), or nitrogen use efficiency (NUE) (mean = 72 g dry weight g-1 N). However, the ratio between root supported tissue (leaves, rhizomes and ramets) and root biomass (S/R) (5.6-8) increased with P availability. In contrast, the growth rate (48-89 mg g-1 d-1) and the biomass ratios A/B (2.4-6.1) and S/R (5.4-10.3) of Typha increased with P availability, while NUE (71-30 g dry weight g-1 N) decreased. The proportion of root laterals was similar in the two species, but Typha had thinner root laterals (diameter = 186 ??m) than Cladium (diameter = 438 ??m) indicating a larger root surface area in Typha. The two species had a similar P use efficiency (PUE) at 10 ??g PI-1 (mean = 1134 g dry weight g-1 P) and at 40 and 80 ??g PI-1 (mean = 482 dry weight g-1 P) but the N/P ratio indicated imbalances in nutrient uptake at a higher P concentration (40 ??g PI-1) in Typha than in Cladium (10 ??g PI-1). The two species had similar root specific P accumulation rate at the two lowest P levels, whereas Typha had 3-13-fold higher P uptake rates at the two highest P levels, indicating a higher nutrient uptake capacity in Typha. The experimental oxygen concentration in the rhizosphere had only limited effect on the growth of the two species and had little effect on biomass partitioning and nutrient use efficiency. The aerenchyma in these species was probably sufficient to maintain adequate root oxygenation under partially oxygen depleted conditions. Cladium had characteristics typical for plants from nutrient poor habitats, which included slow growth rate, low capacity for P uptake and relatively inflexible biomass partitioning in response to increased P availability. In contrast, Typha demonstrated a high degree of flexibility in growth, biomass partitioning, and nutrient accumulation to P availability, similar to species from nutrient rich habitats. Although the N/P ratio indicated that Typha was more nutrient stressed at the low P levels, Typha had a higher capacity for P uptake and was more competitive than Cladium at the applied P concentrations. ?? 2001 Elsevier Science B.V.

MAPK14/p38α-dependent modulation of glucose metabolism affects ROS levels and autophagy during starvation.

PubMed

Desideri, Enrico; Vegliante, Rolando; Cardaci, Simone; Nepravishta, Ridvan; Paci, Maurizio; Ciriolo, Maria Rosa

2014-09-01

Increased glycolytic flux is a common feature of many cancer cells, which have adapted their metabolism to maximize glucose incorporation and catabolism to generate ATP and substrates for biosynthetic reactions. Indeed, glycolysis allows a rapid production of ATP and provides metabolic intermediates required for cancer cells growth. Moreover, it makes cancer cells less sensitive to fluctuations of oxygen tension, a condition usually occurring in a newly established tumor environment. Here, we provide evidence for a dual role of MAPK14 in driving a rearrangement of glucose metabolism that contributes to limiting reactive oxygen species (ROS) production and autophagy activation in condition of nutrient deprivation. We demonstrate that MAPK14 is phosphoactivated during nutrient deprivation and affects glucose metabolism at 2 different levels: on the one hand, it increases SLC2A3 mRNA and protein levels, resulting in a higher incorporation of glucose within the cell. This event involves the MAPK14-mediated enhancement of HIF1A protein stability. On the other hand, MAPK14 mediates a metabolic shift from glycolysis to the pentose phosphate pathway (PPP) through the modulation of PFKFB3 (6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase 3) degradation by the proteasome. This event requires the presence of 2 distinct degradation sequences, KEN box and DSG motif Ser273, which are recognized by 2 different E3 ligase complexes. The mutation of either motif increases PFKFB3 resistance to starvation-induced degradation. The MAPK14-driven metabolic reprogramming sustains the production of NADPH, an important cofactor for many reduction reactions and for the maintenance of the proper intracellular redox environment, resulting in reduced levels of ROS. The final effect is a reduced activation of autophagy and an increased resistance to nutrient deprivation.

Effects of long-term nutrient additions on Arctic tundra, stream, and lake ecosystems: beyond NPP.

PubMed

Gough, Laura; Bettez, Neil D; Slavik, Karie A; Bowden, William B; Giblin, Anne E; Kling, George W; Laundre, James A; Shaver, Gaius R

2016-11-01

Primary producers form the base of food webs but also affect other ecosystem characteristics, such as habitat structure, light availability, and microclimate. Here, we examine changes caused by 5-30+ years of nutrient addition and resulting increases in net primary productivity (NPP) in tundra, streams, and lakes in northern Alaska. The Arctic provides an important opportunity to examine how ecosystems characterized by low diversity and low productivity respond to release from nutrient limitation. We review how responses of algae and plants affect light availability, perennial biotic structures available for consumers, oxygen levels, and temperature. Sometimes, responses were similar across all three ecosystems; e.g., increased NPP significantly reduced light to the substrate following fertilization. Perennial biotic structures increased in tundra and streams but not in lakes, and provided important new habitat niches for consumers as well as other producers. Oxygen and temperature responses also differed. Life history traits (e.g., longevity) of the primary producers along with the fate of detritus drove the responses and recovery. As global change persists and nutrients become more available in the Arctic and elsewhere, incorporating these factors as response variables will enable better prediction of ecosystem changes and feedbacks in this biome and others.

Seasonality directs contrasting food collection behavior and nutrient regulation strategies in ants.

PubMed

Cook, Steven C; Eubanks, Micky D; Gold, Roger E; Behmer, Spencer T

2011-01-01

Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p) to carbohydrate (c) ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer), and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant.

Seasonality Directs Contrasting Food Collection Behavior and Nutrient Regulation Strategies in Ants

PubMed Central

Cook, Steven C.; Eubanks, Micky D.; Gold, Roger E.; Behmer, Spencer T.

2011-01-01

Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p) to carbohydrate (c) ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer), and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant. PMID:21966522

Nutrient production from dairy cattle manure and loading on arable land

PubMed Central

You, Byung-Gu; Choi, Yoon-Seok; Ra, Changsix

2017-01-01

Objective Along with increasing livestock products via intensive rearing, the accumulation of livestock manure has become a serious issue due to the fact that there is finite land for livestock manure recycling via composting. The nutrients from livestock manure accumulate on agricultural land and the excess disembogues into streams causing eutrophication. In order to systematically manage nutrient loading on agricultural land, quantifying the amount of nutrients according to their respective sources is very important. However, there is a lack of research concerning nutrient loss from livestock manure during composting or storage on farms. Therefore, in the present study we quantified the nutrients from dairy cattle manure that were imparted onto agricultural land. Methods Through investigation of 41 dairy farms, weight reduction and volatile solids (VS), total nitrogen (TN), and total phosphorus (TP) changes of dairy cattle manure during the storage and composting periods were analyzed. In order to support the direct investigation and survey on site, the three cases of weight reduction during the storing and composting periods were developed according to i) experiment, ii) reference, and iii) theoretical changes in phosphorus content (ΔP = 0). Results The data revealed the nutrient loading coefficients (NLCs) of VS, TN, and TP on agricultural land were 1.48, 0.60, and 0.66, respectively. These values indicated that the loss of nitrogen and phosphorus was 40% and 34%, respectively, and that there was an increase of VS since bedding materials were mixed with excretion in the barn. Conclusion As result of nutrient-footprint analyses, the amounts of TN and TP particularly entered on arable land have been overestimated if applying the nutrient amount in fresh manure. The NLCs obtained in this study may assist in the development of a database to assess the accurate level of manure nutrient loading on soil and facilitate systematic nutrient management. PMID:27492346

Watershed-Scale Cover Crops Reduce Nutrient Export From Agricultural Landscapes.

NASA Astrophysics Data System (ADS)

Tank, J. L.; Hanrahan, B.; Christopher, S. F.; Trentman, M. T.; Royer, T. V.; Prior, K.

2016-12-01

The Midwestern US has undergone extensive land use change as forest, wetlands, and prairies have been converted to agroecosystems. Today, excess fertilizer nutrients from farm fields enter Midwestern agricultural streams, which degrades both local and downstream water quality, resulting in algal blooms and subsequent hypoxic "dead zones" far from the nutrient source. We are quantifying the benefits of watershed-scale conservation practices that may reduce nutrient runoff from adjacent farm fields. Specifically, research is lacking on whether the planting of winter cover crops in watersheds currently dominated by row-crop agriculture can significantly reduce nutrient inputs to adjacent streams. Since 2013, farmers have planted cover crops on 70% of croppable acres in the Shatto Ditch Watershed (IN), and "saturation level" implementation of this conservation practice has been sustained for 3 years. Every 14 days, we have quantified nutrient loss from fields by sampling nutrient fluxes from multiple subsurface tile drains and longitudinally along the stream channel throughout the watershed. Cover crops improved stream water quality by reducing dissolved inorganic nutrients exported downstream; nitrate-N and DRP concentrations and fluxes were significantly lower in tiles draining fields with cover crops compared to those without. Annual watershed nutrient export also decreased, and reductions in N and P loss ( 30-40%) exceeded what we expected based on only a 6-10% reduction in runoff due to increased watershed water holding capacity. We are also exploring the processes responsible for increased nutrient retention, where they are occurring (terrestrial vs. aquatic) and when (baseflow vs. storms). For example, whole-stream metabolism also responded to cover crop planting, showing reduced variation in primary production and respiration in years after watershed-scale planting of cover crops. In summary, widespread land cover change, through cover crop planting, can significantly reduce annual watershed-scale nutrient export. Moreover, successful outcomes highlighted through demonstration projects may facilitate widespread adoption, making them powerful agents of change for advancing conservation success.

Nitrogen and potassium concentrations in the nutrients solution for melon plants growing in coconut fiber without drainage.

PubMed

Gratieri, Luiz Augusto; Cecílio Filho, Arthur Bernardes; Barbosa, José Carlos; Pavani, Luiz Carlos

2013-01-01

With the objective of evaluating the effects of N and K concentrations for melon plants, an experiment was carried out from July 1, 2011 to January 3, 2012 in Muzambinho city, Minas Gerais State, Brazil. The "Bonus no. 2" was cultivated at the spacing of 1.1 × 0.4. The experimental design was a randomized complete block with three replications in a 4 × 4 factorial scheme with four N concentrations (8, 12, 16, and 20 mmol L(-1)) and four K concentrations (4, 6, 8, and 10 mmol L(-1)). The experimental plot constituted of eight plants. It was observed that the leaf levels of N and K, of N-NO₃ and of K, and the electrical conductivity (CE) of the substrate increased with the increment of N and K in the nutrients' solution. Substratum pH, in general, was reduced with increments in N concentration and increased with increasing K concentrations in the nutrients' solution. Leaf area increased with increments in N concentration in the nutrients solution. Fertigation with solutions stronger in N (20 mmol L(-1)) and K (10 mmol L(-1)) resulted in higher masses for the first (968 g) and the second (951 g) fruits and crop yield (4,425 gm(-2)).

Incorporation of 3H-thymidine by different prokaryotic groups in relation to temperature and nutrients in a lacustrine ecosystem.

PubMed

Boucher, Delphine; Richardot, Mathilde; Thénot, Aurélie; Debroas, Didier

2006-10-01

The incorporation of [3H-methyl] thymidine (3H-TdR) by Eubacteria, bacterial groups (alpha- and beta-Proteobacteria, Cytophaga-Flavobacter), and Archaea was measured according to temperature (7 and 17 degrees C) and nutrient levels (nitrogen, phosphorus, and carbon) in a lacustrine system (Sep, France). Short-term incubation was performed using a combination of microautoradiography and fluorescent in situ hybridization. Irrespective of the temperatures and nutrients studied, all the major phylogenetic bacterial groups assimilated 3H-TdR, and in most of the treatments studied, the proportion of beta-Proteobacteria taking up 3H-TdR was higher than those in the other bacterial groups. The proportion of Bacteria and different bacterial groups studied incorporating 3H-TdR were significantly increased, approximately 1.5-fold, by temperature except for alpha-Proteobacteria (7.6-fold). The nutrient effect was not the same for the different bacterial groups according to the temperatures studied. The proportions of alpha-Proteobacteria (at both temperatures) and Cytophaga-Flavobacter (at 7 degrees C) taking up 3H-TdR were significantly decreased and increased by adding N and P, respectively. Also, adding N, P, and C increased and decreased the percentage of beta-Proteobacteria incorporating 3H-TdR at 7 and 17 degrees C, respectively. The archaeal community showed a similar proportion of active cells (i.e., 3H-TdR) to the bacterial community, and uptake of 3H-TdR by Archaea was significantly increased (P < 0.05) by both temperature and nutrients. Thus, the assimilation of 3H-TdR by bacterial groups and Archaea in lacustrine system is significantly controlled by both temperature and nutrients.

Clonal foraging in perennial wheatgrasses: A strategy for exploiting patchy soil nutrients

USGS Publications Warehouse

Humphrey, L. David; Pyke, David A.

1997-01-01

1. Foraging by means of plasticity in placement of tillers in response to low- and high-nutrient patches was examined in the rhizomatous wheatgrass Elymus lanceolatus ssp. lanceolatus. Its ability to exploit soil nutrient patches was compared to that of the closely related but caespitose E. lanceolatus ssp. wawawaiensis.2. Clones of 14 genets of each taxon were planted in boxes consisting of two 30 × 30 cm cells: the `origin cell' where clones were planted, and the adjacent `destination cell', with each cell containing soil with either low or high levels of nutrients.3. The rhizomatous taxon, which can produce intravaginal, short-rhizome and long-rhizome tillers, preferentially produced short-rhizome and intravaginal tillers in high-nutrient destination cells. Effects of nutrient status of the origin cell as well as of the destination cell on total tiller numbers indicated clonal integration, yet tiller placement responded to local conditions.4. Roots of both taxa accessed nutrients in destination cells (the caespitose subspecies by root growth only), and above-ground biomass of both taxa increased to a similar extent with high-nutrient destination cells. With the patch sizes used in this experiment, root growth was as important as ramet placement in exploiting nutrients in destination cells. 5 There was no relationship between degree of plasticity in ramet placement and biomass of the clone when high-nutrient destination cells were present.

Supplementation of Dried Mealworm (Tenebrio molitor larva) on Growth Performance, Nutrient Digestibility and Blood Profiles in Weaning Pigs

PubMed Central

Jin, X. H.; Heo, P. S.; Hong, J. S.; Kim, N. J.; Kim, Y. Y.

2016-01-01

This experiment was conducted to investigate the effects of dried mealworm (Tenebrio molitor larva) on growth performance, nutrient digestibility and blood profiles in weaning pigs. A total of 120 weaning pigs (28±3 days and 8.04±0.08 kg of body weight) were allotted to one of five treatments, based on sex and body weight, in 6 replicates with 4 pigs per pen by a randomized complete block design. Supplementation level of dried mealworm was 0%, 1.5%, 3.0%, 4.5%, or 6.0% in experimental diet as treatment. Two phase feeding programs (phase I from 0 day to 14 day, phase II from 14 day to 35 day) were used in this experiment. All animals were allowed to access diet and water ad libitum. During phase I, increasing level of dried mealworm in diet linearly improved the body weight (p<0.01), average daily gain (ADG) (p<0.01) and average daily feed intake (ADFI) (p<0.01). During phase II, ADG also tended to increase linearly when pigs were fed higher level of dried mealworm (p = 0.08). In addition, increasing level of dried mealworm improved the ADG (p<0.01), ADFI (p<0.05) and tended to increase gain to feed ratio (p = 0.07) during the whole experimental period. As dried mealworm level was increased, nitrogen retention and digestibility of dry matter as well as crude protein were linearly increased (p = 0.05). In the results of blood profiles, decrease of blood urea nitrogen (linear, p = 0.05) and increase of insulin-like growth factor (linear, p = 0.03) were observed as dried mealworm was increased in diet during phase II. However, there were no significant differences in immunoglobulin A (IgA) and IgG concentration by addition of dried mealworm in the growth trial. Consequently, supplementation of dried mealworm up to 6% in weaning pigs’ diet improves growth performance and nutrient digestibility without any detrimental effect on immune responses. PMID:27282974

Nutrient intake values (NIVs): a recommended terminology and framework for the derivation of values.

PubMed

King, Janet C; Vorster, Hester H; Tome, Daniel G

2007-03-01

Although most countries and regions around the world set recommended nutrient intake values for their populations, there is no standardized terminology or framework for establishing these standards. Different terms used for various components of a set of dietary standards are described in this paper and a common set of terminology is proposed. The recommended terminology suggests that the set of values be called nutrient intake values (NIVs) and that the set be composed of three different values. The average nutrient requirement (ANR) reflects the median requirement for a nutrient in a specific population. The individual nutrient level (INLx) is the recommended level of nutrient intake for all healthy people in the population, which is set at a certain level x above the mean requirement. For example, a value set at 2 standard deviations above the mean requirement would cover the needs of 98% of the population and would be INL98. The third component of the NIVs is an upper nutrient level (UNL), which is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals in a specified life-stage group. The proposed framework for deriving a set of NIVs is based on a statistical approach for determining the midpoint of a distribution of requirements for a set of nutrients in a population (the ANR), the standard deviation of the requirements, and an individual nutrient level that assures health at some point above the mean, e.g., 2 standard deviations. Ideally, a second set of distributions of risk of excessive intakes is used as the basis for a UNL.

Contributions of processed foods to dietary intake in the US from 2003-2008: a report of the Food and Nutrition Science Solutions Joint Task Force of the Academy of Nutrition and Dietetics, American Society for Nutrition, Institute of Food Technologists, and International Food Information Council.

PubMed

Eicher-Miller, Heather A; Fulgoni, Victor L; Keast, Debra R

2012-11-01

Processed foods are an integral part of American diets, but a comparison of the nutrient contribution of foods by level of processing with the recommendations of the Dietary Guidelines for Americans regarding nutrients to encourage or to reduce has not been documented. The mean reported daily dietary intakes of these nutrients and other components were examined among 25,351 participants ≥2 y of age in the 2003-2008 NHANES to determine the contribution of processed food to total intakes. Also examined was the percent contribution of each nutrient to the total reported daily nutrient intake for each of the 5 categories of food that were defined by the level of processing. All processing levels contributed to nutrient intakes, and none of the levels contributed solely to nutrients to be encouraged or solely to food components to be reduced. The processing level was a minor determinant of individual foods' nutrient contribution to the diet and, therefore, should not be a primary factor when selecting a balanced diet.

Highly dynamic cellular-level response of symbiotic coral to a sudden increase in environmental nitrogen.

PubMed

Kopp, C; Pernice, M; Domart-Coulon, I; Djediat, C; Spangenberg, J E; Alexander, D T L; Hignette, M; Meziane, T; Meibom, A

2013-05-14

Metabolic interactions with endosymbiotic photosynthetic dinoflagellate Symbiodinium spp. are fundamental to reef-building corals (Scleractinia) thriving in nutrient-poor tropical seas. Yet, detailed understanding at the single-cell level of nutrient assimilation, translocation, and utilization within this fundamental symbiosis is lacking. Using pulse-chase (15)N labeling and quantitative ion microprobe isotopic imaging (NanoSIMS; nanoscale secondary-ion mass spectrometry), we visualized these dynamic processes in tissues of the symbiotic coral Pocillopora damicornis at the subcellular level. Assimilation of ammonium, nitrate, and aspartic acid resulted in rapid incorporation of nitrogen into uric acid crystals (after ~45 min), forming temporary N storage sites within the dinoflagellate endosymbionts. Subsequent intracellular remobilization of this metabolite was accompanied by translocation of nitrogenous compounds to the coral host, starting at ~6 h. Within the coral tissue, nitrogen is utilized in specific cellular compartments in all four epithelia, including mucus chambers, Golgi bodies, and vesicles in calicoblastic cells. Our study shows how nitrogen-limited symbiotic corals take advantage of sudden changes in nitrogen availability; this opens new perspectives for functional studies of nutrient storage and remobilization in microbial symbioses in changing reef environments. The methodology applied, combining transmission electron microscopy with nanoscale secondary-ion mass spectrometry (NanoSIMS) imaging of coral tissue labeled with stable isotope tracers, allows quantification and submicrometric localization of metabolic fluxes in an intact symbiosis. This study opens the way for investigations of physiological adaptations of symbiotic systems to nutrient availability and for increasing knowledge of global nitrogen and carbon biogeochemical cycling.

Changes in Nutrients and Primary Production in Barrow Tundra Ponds Over the Past 40 Years

NASA Astrophysics Data System (ADS)

Lougheed, V.; Andresen, C.; Hernandez, C.; Miller, N.; Reyes, F.

2012-12-01

The Arctic tundra ponds at the International Biological Program (IBP) site in Barrow, Alaska were studied extensively in the 1970's; however, very little research has occurred there since that time. Due to the sensitivity of this region to climate warming, understanding any changes in the ponds' structure and function over the past 40 years can help identify any potential climate-related impacts. The goal of this study was to determine if the structure and function of primary producers had changed through time, and the association between these changes, urban encroachment and nutrient limitation. Nutrient levels, as well as the biomass of aquatic graminoids (Carex aquatilis and Arctophila fulva), phytoplankton and periphyton were determined in the IBP tundra ponds in both 1971-3 and 2010-12, and in 2010-11 from nearby ponds along an anthropogenic disturbance gradient. Uptake of 14C was also used to measure algal primary production in both time periods and nutrient addition experiments were performed to identify the nutrients limiting algal growth. Similar methods were utilized in the past and present studies. Overall, biomass of graminoids, phytoplankton and periphyton was greater in 2010-12 than that observed in the 1970s. This increased biomass was coincident with warmer water temperatures, increased water column nutrients and deeper active layer depth. Biomass of plants and algae was highest in the ponds closest to the village of Barrow, but no effect of urban encroachment was observed at the IBP ponds. Laboratory incubations indicated that nutrient release from thawing permafrost can explain part of these increases in nutrients and has likely contributed to changes in the primary limiting nutrient. Further studies are necessary to better understand the implications of these trends in primary production to nutrient budgets in the Arctic. The Barrow IBP tundra ponds represent one of the very few locations in the Arctic where long-term data are available on freshwater ecosystem structure and function. Continued monitoring and protection of these invaluable sites is required to help understand the implications of climate change on Arctic freshwater ecosystems.

Periphyton response to increased light and salmon carcass introduction in northern California streams

USGS Publications Warehouse

Ambrose, H.E.; Wilzbach, M.A.; Cummins, K.W.

2004-01-01

Periphyton response to riparian canopy opening and salmon carcass addition in coastal streams of northern California was evaluated in a manipulative field experiment. The experiment followed a split-plot design, with streams as whole plots and two 100-m reaches in each of 6 streams as subplots. At the subplot level, riparian hardwoods were removed from one reach in each stream. At the whole-plot level, carcasses were added to both open- and closed-canopy reaches of 3 of the streams. Thus, treatments consisted of reaches with open or closed canopies, in the presence and absence of carcasses. Nutrient limitation of the periphyton was assessed in 2 streams (1 with carcasses and 1 without carcasses) using nutrient-diffusing clay saucers (N-enriched, P-enriched, N+P-enriched, or unenriched control) incubated in open- and closed-canopy reaches in the streams. Canopy and carcass treatments did not affect gross primary productivity or periphyton biomass on natural substrates. The periphyton assemblage consisted primarily of diatoms in all reaches on all dates. N amendment of agar in nutrient-diffusing, clay saucers and canopy removal increased biofilm ash-free dry mass on the saucers, but carcass introduction did not. Failure of periphyton to respond to carcass addition may have reflected overriding light limitation, inadequate within-stream retention of carcass nutrients, and/or limitations of the study design.

Optimisation Modelling to Assess Cost of Dietary Improvement in Remote Aboriginal Australia

PubMed Central

Brimblecombe, Julie; Ferguson, Megan; Liberato, Selma C.; O'Dea, Kerin; Riley, Malcolm

2013-01-01

Background The cost and dietary choices required to fulfil nutrient recommendations defined nationally, need investigation, particularly for disadvantaged populations. Objective We used optimisation modelling to examine the dietary change required to achieve nutrient requirements at minimum cost for an Aboriginal population in remote Australia, using where possible minimally-processed whole foods. Design A twelve month cross-section of population-level purchased food, food price and nutrient content data was used as the baseline. Relative amounts from 34 food group categories were varied to achieve specific energy and nutrient density goals at minimum cost while meeting model constraints intended to minimise deviation from the purchased diet. Results Simultaneous achievement of all nutrient goals was not feasible. The two most successful models (A & B) met all nutrient targets except sodium (146.2% and 148.9% of the respective target) and saturated fat (12.0% and 11.7% of energy). Model A was achieved with 3.2% lower cost than the baseline diet (which cost approximately AUD$13.01/person/day) and Model B at 7.8% lower cost but with a reduction in energy of 4.4%. Both models required very large reductions in sugar sweetened beverages (−90%) and refined cereals (−90%) and an approximate four-fold increase in vegetables, fruit, dairy foods, eggs, fish and seafood, and wholegrain cereals. Conclusion This modelling approach suggested population level dietary recommendations at minimal cost based on the baseline purchased diet. Large shifts in diet in remote Aboriginal Australian populations are needed to achieve national nutrient targets. The modeling approach used was not able to meet all nutrient targets at less than current food expenditure. PMID:24391790

Fate and effects of nitrogen and phosphorus in shallow vegetated aquatic ecosystems

USGS Publications Warehouse

Fairchild, James F.; Vradenburg, Leigh Ann

2006-01-01

Nitrate concentrations have greatly increased in streams and rivers draining agricultural regions of the Midwestern United States, increasing nitrate transport to the Gulf of Mexico has been implicated in the hypoxic conditions that threaten the productivity of marine fisheries. Increases in nitrate concentrations have been attributed to a combination of factors including agricultural expansion, increased nitrogen application rates, increased tile drainage, and loss of riparian Wetlands, These landscape-level changes have resulted in a decreased natural capacity for nitrogen uptake, removal, and cycling back to the atmosphere. Land managers are increasingly interested in using wetland construction and rehabilitation as a management practice to reduce loss of nitrate from the terrestrial systems. Yet, relatively little is known about the limnological factors involved in nitrate removal by Wetland systems.We conducted a series of studies from 1999-2000 to investigate the functional capacity of shallow, macrophyte-dominated pond wetland systems for uptake, assimilation, and retention of nitrogen (N) and phosphorus (P). We evaluated four factors that were hypothesized to influence nutrient uptake and assimilation: 1) nitrate loading rates; 2) nitrogen to phosphorus (N.P) ratios; 3) frequency of dosing/application; and 4) timing of dose initiation.Nutrient assimilation was rapid; store than 90% of added nutrients were removed from the water column in all treatments. Neither variation in N:P ratios (evaluated range, <13:1 to -114.1), frequency of application (weekly or bi-weekly), nor liming of dose initiation relative to macrophyte development (0%, 15-25%, or 75-90% maximum biomass) had significant effects on nutrient assimilation of wetland community dynamics. Maximum loading of nitrate (60 g N/m2 2.4 g P/m2) applied as six weekly doses stimulated algal communities, but inhibited macrophyte communities.Predicted shifts from a stable state of macrophyte- to phytoplankton-dominance did not occur due to nutrient additions. Macrophytes, phytoplankton, and the sediment surface were all significant factors in the removal of nitrate from the Water column. Overall, these shallow macrophyte-dominated systems provided an efficient means of removing nutrients from the water column. Construction or rehabilitation of shallow, vegetated wetlands may offer promise as land management practices for nutrient removal in agricultural watersheds.

Spatiotemporal patterns of phytoplankton composition and abundance in the Maryland Coastal Bays: The influence of freshwater discharge and anthropogenic activities

NASA Astrophysics Data System (ADS)

Oseji, Ozuem F.; Chigbu, Paulinus; Oghenekaro, Efeturi; Waguespack, Yan; Chen, Nianhong

2018-07-01

The spatial and temporal variations in phytoplankton abundance and community structure in the northern and southern parts of the Maryland Coastal Bays (MCBs) that differ in anthropogenic activities and hydrological characteristics were studied in 2012 and 2013 using photosynthetic pigments as biomarkers. Phytoplankton pigment biomass and diversity were generally higher in the northern bays that receive high nutrient input from St. Martin River, than in the southern bays where nutrient levels were comparatively low. Sites close to the mouths of tributaries in northern and southern bays had higher nutrient levels, which favored the development of dinoflagellates, and nano- and picophytoplankton, than sites closer to the inlets. The microplankton dominated the phytoplankton community in spring (>90%) and decreased in relative abundance into fall (<60%) whereas nanoplankton peaked in summer or fall. Picoplankton relative abundance increased from late spring (<10%, March 2012 & 2013) to summer (40%, July 2012 and August 2013) and was correlated positively with NH4+ and negatively with salinity. The observed spatial and seasonal patterns of phytoplankton relative abundance and diversity are likely due to changes in nutrient concentrations and ratios, driven by variations in freshwater discharge, and selective grazing of phytoplankton. Water quality management in the MCBs should continue to focus on reducing nutrient inputs into the bays.

Cumulative effects of suspended sediments, organic nutrients and temperature stress on early life history stages of the coral Acropora tenuis.

PubMed

Humanes, Adriana; Ricardo, Gerard F; Willis, Bette L; Fabricius, Katharina E; Negri, Andrew P

2017-03-10

Coral reproduction is vulnerable to both declining water quality and warming temperatures, with simultaneous exposures likely compounding the negative impact of each stressor. We investigated how early life processes of the coral Acropora tenuis respond to increasing levels of suspended sediments in combination with temperature or organic nutrients. Fertilization success and embryo development were more sensitive to suspended sediments than to high temperatures or nutrient enrichment, while larval development (after acquisition of cilia) and settlement success were predominantly affected by thermal stress. Fertilization success was reduced 80% by suspended sediments, and up to 24% by temperature, while the addition of nutrients to suspended sediments had no further impact. Larval survivorship was unaffected by any of these treatments. However, settlement success of larvae developing from treatment-exposed embryos was negatively affected by all three stressors (e.g. up to 55% by suspended sediments), while exposure only during later larval stages predominantly responded to temperature stress. Environmentally relevant levels of suspended sediments and temperature had the greatest impacts, affecting more processes than the combined impacts of sediments and nutrients. These results suggest that management strategies to maintain suspended sediments at low concentrations during coral spawning events will benefit coral recruitment, especially with warming climate.

Cumulative effects of suspended sediments, organic nutrients and temperature stress on early life history stages of the coral Acropora tenuis

NASA Astrophysics Data System (ADS)

Humanes, Adriana; Ricardo, Gerard F.; Willis, Bette L.; Fabricius, Katharina E.; Negri, Andrew P.

2017-03-01

Coral reproduction is vulnerable to both declining water quality and warming temperatures, with simultaneous exposures likely compounding the negative impact of each stressor. We investigated how early life processes of the coral Acropora tenuis respond to increasing levels of suspended sediments in combination with temperature or organic nutrients. Fertilization success and embryo development were more sensitive to suspended sediments than to high temperatures or nutrient enrichment, while larval development (after acquisition of cilia) and settlement success were predominantly affected by thermal stress. Fertilization success was reduced 80% by suspended sediments, and up to 24% by temperature, while the addition of nutrients to suspended sediments had no further impact. Larval survivorship was unaffected by any of these treatments. However, settlement success of larvae developing from treatment-exposed embryos was negatively affected by all three stressors (e.g. up to 55% by suspended sediments), while exposure only during later larval stages predominantly responded to temperature stress. Environmentally relevant levels of suspended sediments and temperature had the greatest impacts, affecting more processes than the combined impacts of sediments and nutrients. These results suggest that management strategies to maintain suspended sediments at low concentrations during coral spawning events will benefit coral recruitment, especially with warming climate.

High intensity, short duration rotational grazing on reclaimed cool season tall fescue/legume pastures: II. Forage production, soil and plant tissue comparisons between grazed and ungrazed pastures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlson, K.E.; Erickson, W.R.; Bonine, R.C.

The Midway Mine is located 50 miles south of Kansas City, Kansas straddling the border of Kansas and Missouri. The Pittsburg & Midway Coal Mining Co. mined the area until 1989, when the mine was closed and reclaimed. Approximately 3,750 acres were topsoiled and revegetated with a cool season tall fescue/legume pasture. High intensity, short duration rotational grazing has become the preferred management practice on these pastures. This study evaluated soil and vegetation data collected on 1,250 acres of pasture which was grazed by about 550 cow/calf units. Ongoing monitoring programs are evaluating the effects of rotational grazing. Soil testingmore » includes macro-nutrients, micro-nutrients and microbial activity. Plant tissue analyses monitor levels of principal macro-nutrients and micro-nutrients. Vegetation monitoring consists of measuring forage production. Results were contrasted between pregrazing and postgrazing, and grazed and ungrazed pasture. Agronomic data from the grazed versus ungrazed treatments documented the following results: (1) higher levels of plant tissue nitrate, phosphorus, potassium, calcium, magnesium, sodium and sulfur; (2) higher microbial activity; (3) similar levels of soil nitrate, phosphorus, potassium, calcium, magnesium, sodium and sulfur; and (4) increased biomass production.« less

NF-κB Immunity in the Brain Determines Fly Lifespan in Healthy Aging and Age-Related Neurodegeneration.

PubMed

Kounatidis, Ilias; Chtarbanova, Stanislava; Cao, Yang; Hayne, Margaret; Jayanth, Dhruv; Ganetzky, Barry; Ligoxygakis, Petros

2017-04-25

During aging, innate immunity progresses to a chronically active state. However, what distinguishes those that "age well" from those developing age-related neurological conditions is unclear. We used Drosophila to explore the cost of immunity in the aging brain. We show that mutations in intracellular negative regulators of the IMD/NF-κB pathway predisposed flies to toxic levels of antimicrobial peptides, resulting in early locomotor defects, extensive neurodegeneration, and reduced lifespan. These phenotypes were rescued when immunity was suppressed in glia. In healthy flies, suppressing immunity in glial cells resulted in increased adipokinetic hormonal signaling with high nutrient levels in later life and an extension of active lifespan. Thus, when levels of IMD/NF-κB deviate from normal, two mechanisms are at play: lower levels derepress an immune-endocrine axis, which mobilizes nutrients, leading to lifespan extension, whereas higher levels increase antimicrobial peptides, causing neurodegeneration. Immunity in the fly brain is therefore a key lifespan determinant. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Nutrients affecting brain composition and behavior

NASA Technical Reports Server (NTRS)

Wurtman, R. J.

1987-01-01

This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

The interacting effects of nutrient enrichment and ocean acidification on the growth and physiology of the macroalgae Ulva sp.

NASA Astrophysics Data System (ADS)

Reidenbach, L. B.; Hurd, C. L.; Kubler, J.; Fernandez, P. A.; Leal, P. P.; Noisette, F.; Revill, A. T.; McGraw, C. M.

2016-02-01

Ocean acidification, caused by the increased absorption of carbon dioxide in the ocean, changes the carbon chemistry in the seawater, decreases pH, and alters the chemical speciation of some nitrogenous compounds, such as ammonium. The green macroalgae Ulva spp. are intertidal species that occur worldwide. Ocean acidification may alter the growth response of Ulva sp. to increased nutrients by altering the photosynthetic and nutrient physiology of the algae as well as the bioavailability of nutrients. To determine if there is an interactive effect between ocean acidification and nutrient enrichment Ulva sp. were grown in the lab in a cross of three pCO2 levels under ambient and enriched ammonium concentrations. We predicted that the growth rates of Ulva sp. in ammonium enriched treatments would be enhanced by increased pCO2 relative to those in ambient ammonium concentrations. While growth rate, relative electron transport rates, and chlorophyll content were enhanced by enriched ammonium, there was no interactive effect of high pCO2 and ammonium enrichment. Ammonium uptake rates and ammonium pools were not affected by the pH and ammonium interaction, but nitrate reductase activity increased in the high pCO2, high ammonium treatments. Increased pCO2 has been found to increase Ulva sp. growth rates under some conditions, but this was not the case in this set of experiments. To make realistic predictions of Ulva sp. abundances into the future, based on better understanding of their physiology, ocean acidification experiments should include additional environmental variables such as light intensity and macronutrient supplies that may simultaneously be affected by climate change.

Management of Local Stressors Can Improve the Resilience of Marine Canopy Algae to Global Stressors

PubMed Central

Strain, Elisabeth M. A.; van Belzen, Jim; van Dalen, Jeroen; Bouma, Tjeerd J.; Airoldi, Laura

2015-01-01

Coastal systems are increasingly threatened by multiple local anthropogenic and global climatic stressors. With the difficulties in remediating global stressors, management requires alternative approaches that focus on local scales. We used manipulative experiments to test whether reducing local stressors (sediment load and nutrient concentrations) can improve the resilience of foundation species (canopy algae along temperate rocky coastlines) to future projected global climate stressors (high wave exposure, increasing sea surface temperature), which are less amenable to management actions. We focused on Fucoids (Cystoseira barbata) along the north-western Adriatic coast in the Mediterranean Sea because of their ecological relevance, sensitivity to a variety of human impacts, and declared conservation priority. At current levels of sediment and nutrients, C. barbata showed negative responses to the simulated future scenarios of high wave exposure and increased sea surface temperature. However, reducing the sediment load increased the survival of C. barbata recruits by 90.24% at high wave exposure while reducing nutrient concentrations resulted in a 20.14% increase in the survival and enhanced the growth of recruited juveniles at high temperature. We conclude that improving water quality by reducing nutrient concentrations, and particularly the sediment load, would significantly increase the resilience of C. barbata populations to projected increases in climate stressors. Developing and applying appropriate targets for specific local anthropogenic stressors could be an effective management action to halt the severe and ongoing loss of key marine habitats. PMID:25807516

Intercropping of green garlic (Allium sativum L.) induces nutrient concentration changes in the soil and plants in continuously cropped cucumber (Cucumis sativus L.) in a plastic tunnel.

PubMed

Xiao, Xuemei; Cheng, Zhihui; Meng, Huanwen; Liu, Lihong; Li, Hezi; Dong, Yinxin

2013-01-01

A pot-based experiment was conducted to investigate nutrient concentrations in cucumber plants intercropped with various amounts of green garlic. In addition, the soil nutrient contents were studied over two consecutive growing seasons. The results revealed that the accumulation of biomass and the nutritional elements nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and manganese (Mn) in cucumber plants were significantly increased for intercropping treatments during the two growing seasons compared to monoculture. Conversely, magnesium (Mg) concentrations were decreased in the cucumber plants. Shoot iron (Fe) concentrations decreased whereas root Fe concentrations increased in the intercropping system. Shoot and root zinc (Zn) concentrations decreased during the fall of 2011 but increased during the spring of 2012. Soil organic matter and available N, P and K were significantly increased as the proportion of intercropped green garlic increasing. Medium levels of intercropping green garlic improved cucumber nutrient concentrations the most. The regression analysis showed that the concentrations of most elements were significantly related to the amounts of garlic bulbs, especially the microelements in the spring 2011. The available soil N and organic matter were linearly related to the amounts of garlic bulbs. The results indicate that the nutritional status of the soil and plants of continuously cropped cucumber could be improved by intercropping with green garlic.

Intercropping of Green Garlic (Allium sativum L.) Induces Nutrient Concentration Changes in the Soil and Plants in Continuously Cropped Cucumber (Cucumis sativus L.) in a Plastic Tunnel

PubMed Central

Xiao, Xuemei; Cheng, Zhihui; Meng, Huanwen; Liu, Lihong; Li, Hezi; Dong, Yinxin

2013-01-01

A pot-based experiment was conducted to investigate nutrient concentrations in cucumber plants intercropped with various amounts of green garlic. In addition, the soil nutrient contents were studied over two consecutive growing seasons. The results revealed that the accumulation of biomass and the nutritional elements nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and manganese (Mn) in cucumber plants were significantly increased for intercropping treatments during the two growing seasons compared to monoculture. Conversely, magnesium (Mg) concentrations were decreased in the cucumber plants. Shoot iron (Fe) concentrations decreased whereas root Fe concentrations increased in the intercropping system. Shoot and root zinc (Zn) concentrations decreased during the fall of 2011 but increased during the spring of 2012. Soil organic matter and available N, P and K were significantly increased as the proportion of intercropped green garlic increasing. Medium levels of intercropping green garlic improved cucumber nutrient concentrations the most. The regression analysis showed that the concentrations of most elements were significantly related to the amounts of garlic bulbs, especially the microelements in the spring 2011. The available soil N and organic matter were linearly related to the amounts of garlic bulbs. The results indicate that the nutritional status of the soil and plants of continuously cropped cucumber could be improved by intercropping with green garlic. PMID:23637994

Response of coliform populations in streambed sediment and water column to changes in nutrient concentrations in water.

PubMed

Shelton, D R; Pachepsky, Y A; Kiefer, L A; Blaustein, R A; McCarty, G W; Dao, T H

2014-08-01

As sediments increasingly become recognized as reservoirs of indicator and pathogen microorganisms, an understanding of the persistence of indicator organisms becomes important for assessment and predictions of microbial water quality. The objective of this work was to observe the response of water column and sediment coliform populations to the change in nutrient concentrations in the water column. Survival experiments were conducted in flow-through chambers containing sandy sediments. Bovine feces were collected fresh and introduced into sediment. Sixteen days later, the same fecal material was autoclaved and diluted to provide three levels - 1×, 0.5×, and 0.1× of nutrient concentrations - spike in water column. Total coliforms, Escherichia coli, and total aerobic heterotrophic bacterial concentrations were monitored in water and sediment. Bacteria responded to the nutrient spike with initial growth both in the water column and in sediment. The response of bacterial concentrations in water column was nonlinear, with no significant changes at 0.1 and .5× spikes, but a substantial change at 1× spike. Bacteria in sediment responded to the spikes at all added nutrient levels. Coliform inactivation rates both in sediment and in water after the initial growth occurred, were not significantly different from the inactivation rates before spike. These results indicate that introduction of nutrients into the water column results in nonlinear response of E. coli concentrations both in water and in sediments, followed by the inactivation with the same rate as before introduction of nutrients. Published by Elsevier Ltd.

Nutrient balancing for phytoremediation enhancement of urea manufacturing raw wastewater.

PubMed

Yavari, Sara; Malakahmad, Amirhossein; Sapari, Nasiman B; Yavari, Saba; Khan, Eakalak

2017-11-01

Application of urea manufacturing wastewater to teak (Tectona grandis) trees, a fast growing tropical timber plants, is an environmentally-friendly and cost-effective alternative for treatment of nitrogen-rich wastewater. However, the plant growth is strongly limited by lack of phosphorus (P) and potassium (K) elements when the plants are irrigated with wastewater containing high concentration of nitrogen (N). A greenhouse experiment was conducted to optimize the efficiency of teak-based remediation systems in terms of nutrient balance. Twelve test solutions consisted of 4 levels of P (95, 190, 570, 1140 mgL -1 ) and 3 levels of K (95, 190, 570 mgL -1 ) with a constant level of N (190 mgL -1 ) were applied to teak seedlings every four days during the study period. Evapotranspiration rate, nutrient removal percentage, leaf surface area, dry weight and nutrient contents of experimental plants were determined and compared with those grown in control solution containing only N (N:P:K = 1:0:0). Teak seedlings grown in units with 1:0.5:1 N:P:K ratio were highly effective at nutrient removal upto 47%, 48% and 49% for N, P and K, respectively. Removal efficiency of teak plants grown in other experimental units decreased with increasing P and K concentrations in test solutions. The lowest nutrient removal and plant growth were recorded in units with 1:6:0.5 N:P:K ratio which received the highest ratio of P to K. The findings indicated that teak seedlings functioned effectively as phytoremediation plants for N-rich wastewater treatment when they were being supplied with proper concentrations of P and K. Copyright © 2017. Published by Elsevier Ltd.

Lycopersicon esculentum submitted to Cd-stressful conditions in nutrition solution: Nutrient contents and translocation.

PubMed

Carvalho Bertoli, Alexandre; Gabriel Cannata, Marcele; Carvalho, Ruy; Ribeiro Bastos, Ana Rosa; Puggina Freitas, Matheus; dos Santos Augusto, Amanda

2012-12-01

The increasing number of cases on soil contamination by heavy metals has affected crop yields, besides representing an imminent risk to food. Some of these contaminants, such as cadmium, are very similar to micronutrients and thus more easily absorbed by the plants. This study assessed the effect of increasing amounts of cadmium on the content and translocation of micro and macronutrients in tomato. Tomatoes were grown in Clark's nutrient solution and subjected to increasing levels of Cd: 0, 0.025, 0.1, 0.5 and 1.0mg L(-1). The plants contaminated by cadmium had a maximum reduction in the aerial part compared to the control of: 2.25g kg(-1), 2.80g kg(-1), 18.93mg kg(-1) and 14.15mg kg(-1) for K, Ca, Mn and Zn, respectively. In other parts of the tomato were reduced from 2.3g kg(-1) K in fruits and 280.5mg kg(-1) of Mn in the roots. In addition to changes in the levels of some nutrients, the restricted Cd translocation in 1.15 percent P and 2.8 percent Cu to shoots compared to control, but did not affect the translocation of K, Ca, Mg and Zn. Copyright © 2012 Elsevier Inc. All rights reserved.

Impact of okra (Abelmoschus esculentus) seed flour on nutrients, functional properties and zinc bioavailability of plantain flour.

PubMed

Adetuyi, F O; Adelabu, H A

2011-12-01

In Nigeria, nursing mothers are advised to give their infants plantain flour paste 'amala ogede' with 'ewedu' Corchorus olitorius soup during the process of weaning. Over-matured okra is typically discarded resulting in substantial post-harvest waste; the seed could be processed into okra seed flour for the fortification of plantain flour. The aim of this study is to evaluate the effect of the addition of okra seed flour on the nutrients, functional properties, minerals and zinc bioavailability of plantain flour. Okra seed flour was used to fortify plantain flour in the ratio 90:10, 80:20 and 70:30. The addition of okra seed flour to the plantain flour resulted in a significant increase in the protein, fat, fibre and ash content of the fortified plantain flour, while that of moisture and carbohydrate decreased. The mineral levels of Zn, K and Fe increased significantly while the calcium content decreased. The calculated phytate--zinc molar ratio and [Ca][Phytate]/[Zn] molar ratio of the fortified plantain flour were below the critical levels. The study showed that fortifying plantain flour with okra seed flour resulted in an increase in several nutrients, rendering the zinc more bioavailable. This fortified food has potential as a complimentary food in Nigeria.

Phytoremediation potential of Arundo donax in arsenic-contaminated synthetic wastewater.

PubMed

Mirza, Nosheen; Mahmood, Qaisar; Pervez, Arshid; Ahmad, Raza; Farooq, Robina; Shah, Mohammad Maroof; Azim, Muhammad Rashid

2010-08-01

The present study reports the potential of Arundo donax for phytoextraction of arsenic from synthetic wastewater. A. donax plants were grown under greenhouse conditions in pots containing a nutrient solution amended with increasing doses of As (0, 50, 100, 300, 600 and 1000 microg L(-1)) for 21 days in a completely randomized design. Shoot and roots dry matter production, growth parameters, arsenic and nutrient tissue concentrations were measured at the end of the experiment. Increasing As concentration in nutrient solution caused an increase in shoot and root biomass without toxicity symptoms in A. donax growing under a range of As concentration from 50 to 600 microg L(-1). Elevated oxidative stress was observed at As supplied level of 1000 microg L(-1). The As doses up to 600 microg L(-1) did not affect the growth of A. donax. It is suggested that A. donax plants may be employed to treat contaminated waters containing arsenic concentrations up to 600 microg L(-1). (c) 2010 Elsevier Ltd. All rights reserved.

Nutrient losses and greenhouse gas emissions from dairy production in China: Lessons learned from historical changes and regional differences.

PubMed

Zhang, Nannan; Bai, Zhaohai; Luo, Jiafa; Ledgard, Stewart; Wu, Zhiguo; Ma, Lin

2017-11-15

The dairy industry in China was rapidly expanded and intensified from 1980 to 2010, engendering potential long-term impacts on the environment and natural resources. However, impacts of dairy intensification on nitrogen (N) and phosphorus (P) losses and greenhouse gas (GHG) emissions were unknown. This study was undertaken to examine these relations using the NUtrient flows in Food chains, Environment and Resources use (NUFER)-dairy model. Results showed that milk yield increased by 64% from 1980 to 2010 on average, and the use of concentrate feeds increased by 57% associated with a shift of production from traditional and grassland systems to collective and industrialized systems. At herd level, the N use efficiency (NUE; conversion of N inputs to products) doubled from 7 to 15%, and the P use efficiency (PUE) increased from 10 to 17%, primarily resulting from increased milk yield per cow. In contrast, at the system level, NUE showed a small increase (from 10 to 15%, associated with reduced gaseous losses) while PUE decreased from 46 to 30% due to a large increase in manure discharges. This is attributed to decoupling of feed and dairy production, as the proportion of manure N and P recycled to cropland decreased by 52% and 54%, respectively. Despite this, the average total N loss decreased from 63 to 48gkg -1 milk, and the average GHG emissions from 1.7 to 1.1kgCO 2 equivalentkg -1 milk associated with increased per-cow productivity. However, average P loss increased from 1.4 to 2.8gPkg -1 milk due to higher discharge rate to wastewater and landfill in collective and industrialized systems. Anyhow, average N and P losses exceeded levels in developed countries. There were large regional variations in nutrient use efficiency, nutrient losses and GHG emissions in China, largely determined by the dairy production structure. Average N losses and GHG emissions per unit of milk showed a negative correlation with production intensification based on the proportion of farms in collective or industrialized systems, while average P losses per unit of milk in different regions showed a positive relationship with intensification. In conclusion, dairy intensification was associated with increased milk yield per cow and reduced average N losses and GHG emissions per unit of milk, but reduced system level PUE and manure recycling contributed to high levels of total N and P losses. Dairy production in China is likely to continue to be intensified as a result of rising milk demand, and significant improvements must be made in manure management to control N and P losses and GHG emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

Scale and legacy controls on catchment nutrient export regimes

NASA Astrophysics Data System (ADS)

Howden, N. J. K.; Burt, T.; Worrall, F.

2017-12-01

Nutrient dynamics in river catchments are complex: water and chemical fluxes are highly variable in low-order streams, but this variability declines as fluxes move through higher-order reaches. This poses a major challenge for process understanding as much effort is focussed on long-term monitoring of the main river channel (a high-order reach), and therefore the data available to support process understanding are predominantly derived from sites where much of the transient response of nutrient export is masked by the effect of averaging over both space and time. This may be further exacerbated at all scales by the accumulation of legacy nutrient sources in soils, aquifers and pore waters, where historical activities have led to nutrient accumulation where the catchment system is transport limited. Therefore it is of particular interest to investigate how the variability of nutrient export changes both with catchment scale (from low to high-order catchment streams) and with the presence of legacy sources, such that the context of infrequent monitoring on high-order streams can be better understood. This is not only a question of characterising nutrient export regimes per se, but also developing a more thorough understanding of how the concepts of scale and legacy may modify the statistical characteristics of observed responses across scales in both space and time. In this paper, we use synthetic data series and develop a model approach to consider how space and timescales combine with impacts of legacy sources to influence observed variability in catchment export. We find that: increasing space and timescales tend to reduce the observed variance in nutrient exports, due to an increase in travel times and greater mixing, and therefore averaging, of sources; increasing the influence of legacy sources inflates the variance, with the level of inflation dictated by the residence time of the respective sources.

Nutrient resources for crop production in the tropics

PubMed Central

Vlek, P. L. G.; Kühne, R. F.; Denich, M.

1997-01-01

For the foreseeable future a majority of the population, and almost all the mal- and under-nourished, will continue to be found in the tropics and subtropics. Food security in these parts of the world will have to be met largely from local resources. The productivity of the land is to a large extent determined by the fertlity of the soil, which in turn is mostly determined by its organic matter content and stored nutrients. Soil organic matter is readily lost when organic matter inputs are reduced upon cultivation and more so upon intensification. The concomitant loss of topsoil and possible exposure of subsoil acidity may cause further soil degradation.
Plant nutrients to replenish what is yearly taken from the soil to meet the demands for food and fibre amount to 230 million tonnes (Mt). Current fertilizer consumption stands at about 130 Mt of N, P2O5,and K2O, supplemented by an estimated 90 Mt of N from biological nitrogen fixation worldwide. Although 80 per cent of the population lives in the developing world, only half the world's fertilizer is consumed there. Yet, as much as 50% of the increase in agricultural productivity in the developing world is due to the adoption of fertilizers. World population growth will cause a doubling in these nutrients requirements for the developing world by 2020, which, in the likely case of inadequate production, will need to be met from soil reserves. Because expansion of the cultivable land area is reaching its limits, the reliance on nutrient inputs and their efficient use is bound to grow.
With current urban expansion, nutrients in harvested products are increasingly lost from the rural environment as a whole. Estimates of soil nutrient depletion rates for sub-Saharan Africa (SSA) are alarmingly high. The situation may be more favourable in Latin America and Asia where fertilizer inputs are tenfold those of SSA. Closing the nutrient cycle at a community level in rural areas may be tedious; on an inter-regional level it is associated with considerable costs of collection, detoxification and transportation to the farms. Yet, at the rate at which some of the non-renewable resources such as phosphorus and potassium are being exploited, recycling of these nutrients will soon be required.

Changes in nutrient mass balances over time and related drivers for 54 New York State dairy farms.

PubMed

Soberon, Melanie A; Cela, Sebastian; Ketterings, Quirine M; Rasmussen, Caroline N; Czymmek, Karl J

2015-08-01

Whole-farm nutrient mass balances (NMB) can assist producers in evaluation and monitoring the nutrient status of dairy farms over time. Most of the previous studies that report NMB for dairy farms were conducted over 1 to 3 yr. In this study, annual N, P, and K mass balances were assessed on 54 dairy farms in New York State for 4 to 6 yr between 2005 and 2010 with the objectives to (1) document changes in NMB over time and drivers for change, and (2) identify nutrient use efficiency parameters that predicted the potential for improvement in NMB. The study farms varied in size (42 small, 12 medium and large) and management practices. Phosphorus, K, and 2 N balances (N1 without N2 fixation, and N2 including N2 fixation) were calculated. In general, farms with high initial NMB levels reduced them over time whereas farms with negative NMB tended to increase their NMB, demonstrating a tendency across all farms to move toward more optimal NMB levels over time. Sixty-three to 76% of farms (depending on the nutrient) reduced their NMB per hectare over the 4 to 6 yr, and 55 to 61% of these farms were able to do so while increasing milk production per cow. Across all farms, the overall reduction in NMB per hectare averaged -22kg of N/ha for N1 (29% reduction), -16kg of N/ha for N2 (15% reduction), -4kg of P/ha (36% reduction), and -10kg of K/ha (29% reduction). Change in feed imports was the most important driver for change in N and P balances across farms, whereas adjustments in both feed and fertilizer imports affected the K balances. Key predictors of potential areas for improvement in NMB over time include total nutrient imports, feed imports, animal density, percentage of farm-produced feed and nutrients, and feed nutrient use efficiency. Overall, this study highlights the opportunities of an adaptive management approach that includes NMB assessments to evaluate and monitor changes in nutrient use efficiency and cost-efficiency over time. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Nutrient Digestibility and Metabolizable Energy Content of Mucuna pruriens Whole Pods Fed to Growing Pelibuey Lambs.

PubMed

Loyra-Tzab, Enrique; Sarmiento-Franco, Luis Armando; Sandoval-Castro, Carlos Alfredo; Santos-Ricalde, Ronald Herve

2013-07-01

The nutrient digestibility, nitrogen balance and in vivo metabolizable energy supply of Mucuna pruriens whole pods fed to growing Pelibuey lambs was investigated. Eight Pelibuey sheep housed in metabolic crates were fed increasing levels of Mucuna pruriens pods: 0 (control), 100 (Mucuna100), 200 (Mucuna200) and 300 (Mucuna300) g/kg dry matter. A quadratic (p<0.002) effect was observed for dry matter (DM), neutral detergent fibre (aNDF), nitrogen (N) and gross energy (GE) intakes with higher intakes in the Mucuna100 and Mucuna200 treatments. Increasing M. pruriens in the diets had no effect (p>0.05) on DM and GE apparent digestibility (p<0.05). A linear reduction in N digestibility and N retention was observed with increasing mucuna pod level. This effect was accompanied by a quadratic effect (p<0.05) on fecal-N and N-balance which were higher in the Mucuna100 and Mucuna200 treatments. Urine-N excretion, GE retention and dietary estimated nutrient supply (metabolizable protein and metabolizable energy) were not affected (p>0.05). DM, N and GE apparent digestibility coefficient of M. pruriens whole pods obtained through multiple regression equations were 0.692, 0.457, 0.654 respectively. In vivo DE and ME content of mucuna whole pod were estimated in 11.0 and 9.7 MJ/kg DM. It was concluded that whole pods from M. pruriens did not affect nutrient utilization when included in an mixed diet up to 200 g/kg DM. This is the first in vivo estimation of mucuna whole pod ME value for ruminants.

Arsenate exposure affects amino acids, mineral nutrient status and antioxidants in rice (Oryza sativa L.) genotypes.

PubMed

Dwivedi, S; Tripathi, R D; Tripathi, P; Kumar, A; Dave, R; Mishra, S; Singh, R; Sharma, D; Rai, U N; Chakrabarty, D; Trivedi, P K; Adhikari, B; Bag, M K; Dhankher, O P; Tuli, R

2010-12-15

Simulated pot experiments were conducted on four rice (Oryza sativa L.) genotypes (Triguna, IR-36, PNR-519, and IET-4786) to examine the effects of As(V) on amino acids and mineral nutrient status in grain along with antioxidant response to arsenic exposure. Rice genotypes responded differentially to As(V) exposure in terms of amino acids and antioxidant profiles. Total amino acid content in grains of all rice genotypes was positively correlated with arsenic accumulation. While, most of the essential amino acids increased in all cultivars except IR-36, glutamic acid and glycine increased in IET-4786 and PNR-519. The level of nonprotein thiols (NPTs) and the activities of superoxide dismutase (SOD; EC 1.15.1.1), glutathione reductase (GR; EC 1.6.4.2) and ascorbate peroxidase (APX; EC 1.11.1.11) increased in all rice cultivars except IET-4786. A significant genotypic variation was also observed in specific arsenic uptake (SAU; mg kg(-1)dw), which was in the order of Triguna (134) > IR-36 (71) > PNR-519 (53) > IET-4786 (29). Further, application of As(V) at lower doses (4 and 8 mg L(-1) As) enhanced the accumulation of selenium (Se) and other nutrients (Fe, P, Zn, and S), however, higher dose (12 mg L(-1) As) limits the nutrient uptake in rice. In conclusion, low As accumulating genotype, IET-4786, which also had significantly induced level of essential amino acids, seems suitable for cultivation in moderately As contaminated soil and would be safe for human consumption.

Holocene environmental change and development of the nutrient budget of histosols in North Iceland

NASA Astrophysics Data System (ADS)

Möckel, Susanne Claudia; Erlendsson, Egill; Gísladóttir, Guðrún

2017-04-01

Backround and aims: Little is known about vegetation changes in Icelandic peatlands in the context of soil chemical properties. By connecting soil chemical and physical characteristics with palaeobotanical data we examined interactions between climate, histosols, vegetation and land use during the Holocene. Methods: Exchangeable base cations, cation exchange capacity (CEC), base saturation (BS), and decomposition rates using carbon:nitrogen ratio (C:N) and von Post humification and soil physical properties were determined. Vegetation development was reconstructed based on pollen analysis. The impact of geographic location was examined by comparing results from three sloping fens (coastal, inland and highland fringe). Results: Minerogenic content was highest in the proximity of the active volcanic belt, reflected in higher C:N and nutrient content. The site closest to the sea revealed exceptionally high BS. C:N was either stable throughout the profile or increased with depth. Plant species richness, species evenness, and pollen concentrations were greatest at the site with lowest nutrient levels. Conclusions: Minerogenic content facilitates the ability to bind nutrients. Lower fertility levels optimize plant growth. C:N alone is not a reliable indicator of decomposition rates, but depends on the quality of the organic parent material. Environmental conditions driven by climate changes caused alterations in vegetation and soil properties before the settlement. Nevertheless, overall the histosols showed resilience towards severe degradation. After the settlement (c. AD 870), the soils struggled to buffer the impact caused by destruction of vegetation and increased erosion. This study increases our understanding of environmental and anthropogenic determinants of soil- and vegetation development.

The elemental stoichiometry (C, Si, N, P) of the Hebrides Shelf and its role in carbon export

NASA Astrophysics Data System (ADS)

Painter, Stuart C.; Hartman, Susan E.; Kivimäe, Caroline; Salt, Lesley A.; Clargo, Nicola M.; Daniels, Chris J.; Bozec, Yann; Daniels, Lucie; Allen, Stephanie; Hemsley, Victoria S.; Moschonas, Grigorios; Davidson, Keith

2017-12-01

A detailed analysis of the internal stoichiometry of a temperate latitude shelf sea system is presented which reveals strong vertical and horizontal gradients in dissolved nutrient and particulate concentrations and in the elemental stoichiometry of those pools. Such gradients have implications for carbon and nutrient export from coastal waters to the open ocean. The mixed layer inorganic nutrient stoichiometry shifted from balanced N:P in winter, to elevated N:P in spring and to depleted N:P in summer, relative to the Redfield ratio. This pattern suggests increased likelihood of P limitation of fast growing phytoplankton species in spring and of N limitation of slower growing species in summer. However, as only silicate concentrations were below potentially limiting concentrations during summer and autumn the stoichiometric shifts in inorganic nutrient N:P are considered due to phytoplankton nutrient preference patterns rather than nutrient exhaustion. Elevated particulate stoichiometries corroborate non-Redfield optima underlying organic matter synthesis and nutrient uptake. Seasonal variation in the stoichiometry of the inorganic and organic nutrient pools has the potential to influence the efficiency of nutrient export. In summer, when organic nutrient concentrations were at their highest and inorganic nutrient concentrations were at their lowest, the organic nutrient pool was comparatively C poor whilst the inorganic nutrient pool was comparatively C rich. The cross-shelf export of these pools at this time would be associated with different efficiencies regardless of the total magnitude of exchange. In autumn the elemental stoichiometries increased with depth in all pools revealing widespread carbon enrichment of shelf bottom waters with P more intensely recycled than N, N more intensely recycled than C, and Si weakly remineralized relative to C. Offshelf carbon fluxes were most efficient via the inorganic nutrient pool, intermediate for the organic nutrient pool and least efficient for the particulate pool. N loss from the shelf however was most efficient via the dissolved organic nutrient pool. Mass balance calculations suggest that 28% of PO43-, 34% of NO3- and 73% of Si drawdown from the mixed layer fails to reappear in the benthic water column thereby indicating the proportion of the nutrient pools that must be resupplied from the ocean each year to maintain shelf wide productivity. Loss to the neighbouring ocean, the sediments, transference to the dissolved organic nutrient pool and higher trophic levels are considered the most likely fate for these missing nutrients.

Nutrient fluxes at the landscape level and the R* rule

USGS Publications Warehouse

Ju, Shu; DeAngelis, Donald L.

2010-01-01

Nutrient cycling in terrestrial ecosystems involves not only the vertical recycling of nutrients at specific locations in space, but also biologically driven horizontal fluxes between different areas of the landscape. This latter process can result in net accumulation of nutrients in some places and net losses in others. We examined the effects of such nutrient-concentrating fluxes on the R* rule, which predicts that the species that can survive in steady state at the lowest level of limiting resource, R*, can exclude all competing species. To study the R* rule in this context, we used a literature model of plant growth and nutrient cycling in which both nutrients and light may limit growth, with plants allocating carbon and nutrients between foliage and roots according to different strategies. We incorporated the assumption that biological processes may concentrate nutrients in some parts of the landscape. We assumed further that these processes draw nutrients from outside the zone of local recycling at a rate proportional to the local biomass density. Analysis showed that at sites where there is a sufficient biomass-dependent accumulation of nutrients, the plant species with the highest biomass production rates (roughly corresponding to the best competitors) do not reduce locally available nutrients to a minimum concentration level (that is, minimum R*), as expected from the R* rule, but instead maximize local nutrient concentration. These new results require broadening of our understanding of the relationships between nutrients and vegetation competition on the landscape level. The R* rule is replaced by a more complex criterion that varies across a landscape and reduces to the R* rule only under certain limiting conditions.

Effects of inclusion level on nutrient digestibility and energy content of wheat middlings and soya bean meal for growing pigs.

PubMed

Huang, Qiang; Piao, Xiangshu; Liu, Ling; Li, Defa

2013-01-01

Two experiments were conducted to determine the effects of inclusion level of wheat middlings and soya bean meal on apparent total tract digestibility (ATTD) of energy and chemical components of these ingredients in growing pigs. Furthermore, the effects of the inclusion level on their contents of digestible energy (DE) and metabolisable energy (ME) were also determined by the difference method. In Experiment 1, six diets were fed to 36 growing pigs according to a completely randomised design. The basal diet was a corn-soya bean meal diet while the other five diets contained 9.6%, 19.2%, 28.8%, 38.4% or 48.0% of wheat middlings added at the expense of corn and soya bean meal. The measured digestibility of energy and most nutrients of wheat middlings increased (p < 0.05) with increasing levels of that ingredient. Equations were obtained to predict digestibility by inclusion level. At an inclusion level of 9.6% wheat middlings, their DE contents were significantly lower (8.9 MJ/kg DM) than for the higher levels (10.7 to 11.9 MJ/kg DM, p < 0.01). In Experiment 2, three diets were fed to 18 growing pigs according to a completely randomised block design. The basal diet was a corn-based diet while the other two diets were based on corn and two levels of soya bean meal (22.2% and 33.6%). The content of DE in soya bean meal did not differ at 22.2% and 33.6% inclusion levels (16.2 and 16.3 MJ/kg DM, respectively), but the digestibility of dry matter (DM), organic matter and carbohydrates was increased at a higher inclusion level (p < 0.05). This study revealed that the estimated digestibility of nutrients from soya bean meal and wheat middlings was affected by their dietary inclusion levels. For soya bean meal, the estimated energy contents was independent of its inclusion level, but not for wheat middlings. Therefore, the inclusion level of wheat middlings has to be considered for estimating their energy value.

Herbivory and eutrophication mediate grassland plant nutrient responses across a global climatic gradient

USGS Publications Warehouse

Anderson, T. Michael; Griffith, Daniel M.; Grace, James B.; Lind, Eric M.; Adler, Peter B.; Biederman, Lori A.; Blumenthal, Dana M.; Daleo, Pedro; Firn, Jennifer; Hagenah, Nicole; Harpole, W. Stanley; MacDougall, Andrew S.; McCulley, Rebecca L.; Prober, Suzanne M.; Risch, Anita C.; Sankaran, Mahesh; Schütz, Martin; Seabloom, Eric W.; Stevens, Carly J.; Sullivan, Lauren; Wragg, Peter; Borer, Elizabeth T.

2018-01-01

Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, but results were contingent on soil fertility and the proportion of grass biomass relative to other functional types. Total plant nutrient pools diverged strongly in response to herbivore exclusion when fertilized; responses were largest in ungrazed plots at low rainfall, whereas herbivore grazing dampened the plant community nutrient responses to fertilization. Our study highlights (1) the importance of climate in determining plant nutrient concentrations mediated through effects on plant biomass, (2) that eutrophication affects grassland nutrient pools via both soil and atmospheric pathways and (3) that interactions among soils, herbivores and eutrophication drive plant nutrient responses at small scales, especially at water‐limited sites.

Herbivory and eutrophication mediate grassland plant nutrient responses across a global climatic gradient.

PubMed

Anderson, T Michael; Griffith, Daniel M; Grace, James B; Lind, Eric M; Adler, Peter B; Biederman, Lori A; Blumenthal, Dana M; Daleo, Pedro; Firn, Jennifer; Hagenah, Nicole; Harpole, W Stanley; MacDougall, Andrew S; McCulley, Rebecca L; Prober, Suzanne M; Risch, Anita C; Sankaran, Mahesh; Schütz, Martin; Seabloom, Eric W; Stevens, Carly J; Sullivan, Lauren L; Wragg, Peter D; Borer, Elizabeth T

2018-04-01

Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot-level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, but results were contingent on soil fertility and the proportion of grass biomass relative to other functional types. Total plant nutrient pools diverged strongly in response to herbivore exclusion when fertilized; responses were largest in ungrazed plots at low rainfall, whereas herbivore grazing dampened the plant community nutrient responses to fertilization. Our study highlights (1) the importance of climate in determining plant nutrient concentrations mediated through effects on plant biomass, (2) that eutrophication affects grassland nutrient pools via both soil and atmospheric pathways and (3) that interactions among soils, herbivores and eutrophication drive plant nutrient responses at small scales, especially at water-limited sites. © 2018 by the Ecological Society of America.

Rising nutrient-pulse frequency and high UVR strengthen microbial interactions

PubMed Central

Cabrerizo, Marco J.; Medina-Sánchez, Juan Manuel; Dorado-García, Irene; Villar-Argaiz, Manuel; Carrillo, Presentación

2017-01-01

Solar radiation and nutrient pulses regulate the ecosystem’s functioning. However, little is known about how a greater frequency of pulsed nutrients under high ultraviolet radiation (UVR) levels, as expected in the near future, could alter the responses and interaction between primary producers and decomposers. In this report, we demonstrate through a mesocosm study in lake La Caldera (Spain) that a repeated (press) compared to a one-time (pulse) schedule under UVR prompted higher increases in primary (PP) than in bacterial production (BP) coupled with a replacement of photoautotrophs by mixotrophic nanoflagellates (MNFs). The mechanism underlying these amplified phytoplanktonic responses was a dual control by MNFs on bacteria through the excretion of organic carbon and an increased top-down control by bacterivory. We also show across a 6-year whole-lake study that the changes from photoautotrophs to MNFs were related mainly to the frequency of pulsed nutrients (e.g. desert dust inputs). Our results underscore how an improved understanding of the interaction between chronic and stochastic environmental factors is critical for predicting ongoing changes in ecosystem functioning and its responses to climatically driven changes. PMID:28252666

Antioxidant nutrient intake and supplements as potential moderators of cognitive decline and cardiovascular disease in obstructive sleep apnea.

PubMed

Baldwin, Carol M; Bootzin, Richard R; Schwenke, Dawn C; Quan, Stuart F

2005-12-01

Cognitive deficits and cardiovascular disease (CVD) are comorbid conditions frequently associated with obstructive sleep apnea (OSA). Oxygen free radical release and its differential regulation of cytokine synthesis and immune modulation resulting from OSA-related hypoxic events have been hypothesized as the underlying mechanism(s) for the cognitive deficits and CVD in OSA. A number of studies have suggested that increased levels of oxidative stress and/or antioxidant deficiencies may also be risk factors in cognitive decline and CVD. The influence of antioxidant nutrients and supplements, such as Vitamins B6, B12, C, E, folic acid, alpha-lipoic acid and Coenzyme Q(10) on cognitive decline and CVD have been investigated. The influence of antioxidant nutrients or supplements on OSA remains to be investigated. Even if dietary or supplemental antioxidants do not prove to be effective therapies for OSA, dietary assessment and prescription to increase dietary intake of neuro- and cardio-protective nutrients may make it possible to reduce some of the cognitive and cardiovascular sequelae associated with OSA.

Rising nutrient-pulse frequency and high UVR strengthen microbial interactions

NASA Astrophysics Data System (ADS)

Cabrerizo, Marco J.; Medina-Sánchez, Juan Manuel; Dorado-García, Irene; Villar-Argaiz, Manuel; Carrillo, Presentación

2017-03-01

Solar radiation and nutrient pulses regulate the ecosystem’s functioning. However, little is known about how a greater frequency of pulsed nutrients under high ultraviolet radiation (UVR) levels, as expected in the near future, could alter the responses and interaction between primary producers and decomposers. In this report, we demonstrate through a mesocosm study in lake La Caldera (Spain) that a repeated (press) compared to a one-time (pulse) schedule under UVR prompted higher increases in primary (PP) than in bacterial production (BP) coupled with a replacement of photoautotrophs by mixotrophic nanoflagellates (MNFs). The mechanism underlying these amplified phytoplanktonic responses was a dual control by MNFs on bacteria through the excretion of organic carbon and an increased top-down control by bacterivory. We also show across a 6-year whole-lake study that the changes from photoautotrophs to MNFs were related mainly to the frequency of pulsed nutrients (e.g. desert dust inputs). Our results underscore how an improved understanding of the interaction between chronic and stochastic environmental factors is critical for predicting ongoing changes in ecosystem functioning and its responses to climatically driven changes.

Nutrient Digestibility, Rumen Microbial Protein Synthesis, and Growth Performance in Sheep Consuming Rations Containing Sea Buckthorn Pomace.

PubMed

Hao, X Y; Diao, X G; Yu, S C; Ding, N; Mu, C T; Zhao, J X; Zhang, J X

2018-05-12

This experiment was conducted to investigate nutrient digestibility, rumen microbial protein synthesis, and growth performance when different proportions of sea buckthorn pomace (SBP) were included in the diet of sheep. A total of forty1/2 Dorper × 1/2 thin-tailed Han ram lambs (BW= 22.2 ± 0.92 kg, Age =120 ± 11 d; mean ± SD) were selected and divided into four groups in a randomized design, and were randomly allocated to 1 of 4 treatment diets. Diets were formulated isonitrogenously and contained different levels of SBP: 1) 0% SBP (control); 2) 7.8% of DM SBP (8SBP); 3)16.0% of DM SBP (16SBP); and 4) 23.5% of DM SBP (24SBP). A portion of corn and forages were replaced with SBP. Dry matter intake and average daily gain increased linearly (P=0.001), but feed efficiency was not affected (P≥0.460) by increasing SBP inclusion rate. As the SBP inclusion increased, organic matter, neutral detergent fiber, and acid detergent fiber digestibility decreased linearly (P≤0.005) and that crude protein increased linearly (P=0.012). Response to inclusion level of SBP was quadratic (P=0.003) for the estimated microbial crude protein yield with the greatest at intermediate SBP levels. For intestinally absorbable dietary protein, a quadratic (P=0.029) effects was observed among treatments. The metabolizable protein supplies was linearly (P<0.0001) improved with increasing SBP inclusion rate. The results indicated that sea buckthorn pomace can be incorporated in the ration of ram lambs and improve metabolizable protein supply and average daily gain. However, high content of it in the diet was adverse for nutrient digestibility. The optimal proportion was 16.0% under the condition of this experiment.

[Effects of mulching management on biomass of Phyllostachys praecox and soil fertility].

PubMed

Zhai, Wan Lu; Yang, Chuan Bao; Zhang, Xiao Ping; Gao, Gui Bin; Zhong, Zhe Ke

2018-04-01

We analyzed the dynamics of stand growth and soil nutrient availability during the degradation processes of Phyllostachys praecox plantation, taking the advantage of bamboo forest stands with different mulching ages (0, 3, 6, 9 and 12 a). The results showed the aboveground and belowground biomass of bamboo forest reached the maximum value when they were covered by three years, which was significantly increased by 14.6% and 146.6% compared with the control. The soil nutrient content was affected by the mulching age and soil layer. Soil nutrients gradually accumulated in upper layer. Soil organic carbon and total nitrogen content were increased with the increases of coverage years. The soil total phosphorus content at different soil layers showed a trend of decreasing first and then increasing. It was the lowest level in the surface layer (0-20 cm) and the bottom (40-60 cm) in 6 years, and the subsurface (20-40 cm) soil reached the lowest level in three years. The total potassium content kept increasing in 0-20 cm soil layer, but decreased during the first three years of mulching and then increased in 20-60 cm soil layer. The comprehensive index of soil fertility quality was greatly improved after nine years mulching, with fertility of subsurface soil being better than that of surface and bottom soils. There was no relationship between the soil fertility index and biomass of different organs in bamboo in the different mulching ages. In the subsurface, however, nitrogen content was negatively related to leaf biomass and potassium was negatively correlated with the biomass of leaves and whip roots. Our results indicated that excessive accumulation of soil nutrients seriously inhibited the propagation and biomass accumulation of P. praecox after long-term mulching management and a large amount of fertilizer, which further aggravated the degradation of bamboo plantation.

Optimal methylation noise for best chemotactic performance of E. coli

NASA Astrophysics Data System (ADS)

Dev, Subrata; Chatterjee, Sakuntala

2018-03-01

In response to a concentration gradient of chemoattractant, E. coli bacterium modulates the rotational bias of flagellar motors which control its run-and-tumble motion, to migrate towards regions of high chemoattractant concentration. Presence of stochastic noise in the biochemical pathway of the cell has important consequences on the switching mechanism of motor bias, which in turn affects the runs and tumbles of the cell in a significant way. We model the intracellular reaction network in terms of coupled time evolution of three stochastic variables—kinase activity, methylation level, and CheY-P protein level—and study the effect of methylation noise on the chemotactic performance of the cell. In presence of a spatially varying nutrient concentration profile, a good chemotactic performance allows the cell to climb up the concentration gradient quickly and localize in the nutrient-rich regions in the long time limit. Our simulations show that the best performance is obtained at an optimal noise strength. While it is expected that chemotaxis will be weaker for very large noise, it is counterintuitive that the performance worsens even when noise level falls below a certain value. We explain this striking result by detailed analysis of CheY-P protein level statistics for different noise strengths. We show that when the CheY-P level falls below a certain (noise-dependent) threshold the cell tends to move down the concentration gradient of the nutrient, which has a detrimental effect on its chemotactic response. This threshold value decreases as noise is increased, and this effect is responsible for noise-induced enhancement of chemotactic performance. In a harsh chemical environment, when the nutrient degrades with time, the amount of nutrient intercepted by the cell trajectory is an effective performance criterion. In this case also, depending on the nutrient lifetime, we find an optimum noise strength when the performance is at its best.

Water quality trends in New Zealand rivers: 1989-2009.

PubMed

Ballantine, Deborah J; Davies-Colley, Robert J

2014-03-01

Recent assessments of water quality in New Zealand have indicated declining trends, particularly in the 40 % of the country's area under pasture. The most comprehensive long-term and consistent water quality dataset is the National Rivers Water Quality Network (NRWQN). Since 1989, monthly samples have been collected at 77 NRWQN sites on 35 major river systems that, together, drain about 50 % of New Zealand's land area. Trend analysis of the NRWQN data shows increasing nutrient concentrations, particularly nitrogen (total nitrogen and nitrate), over 21 years (1989-2009). Total nitrogen and nitrate concentrations were increasing significantly over the first 11 years (1989-2000), but for the more recent 10-year period, only nitrate concentrations continued to increase sharply. Also, the increasing phosphorus trends over the first 11 years (1989-2000) levelled off over the later 10-year period (2000-2009). Conductivity has also increased over the 21 years (1989-2009). Visual clarity has increased over the full time period which may be the positive result of soil conservation measures and riparian fencing. NRWQN data shows that concentrations of nutrients increase, and visual clarity decreases (i.e. water quality declines), with increasing proportions of pastoral land in catchments. As such, the increasing nutrient trends may reflect increasing intensification of pastoral agriculture.

Uptake of different species of iodine by water spinach and its effect to growth.

PubMed

Weng, Huan-Xin; Yan, Ai-Lan; Hong, Chun-Lai; Xie, Lin-Li; Qin, Ya-Chao; Cheng, Charles Q

2008-08-01

A hydroponic experiment has been carried out to study the influence of iodine species [iodide (I(-)), iodate (IO(-)(3)), and iodoacetic acid (CH(2)ICOO(-))] and concentrations on iodine uptake by water spinach. Results show that low levels of iodine in the nutrient solution can effectively stimulate the growth of biomass of water spinach. When iodine levels in the nutrient solution are from 0 to 1.0 mg/l, increases in iodine levels can linearly augment iodine uptake rate by the leafy vegetables from all three species of iodine, and the uptake effects are in the following order: CH(2)ICOO(-) >I(-)>IO(-)(3). In addition, linear correlation was observed between iodine content in the roots and shoots of water spinach, and their proportion is 1:1. By uptake of I(-), vitamin C (Vit C) content in water spinach increased, whereas uptake of IO(-)(3) and CH(2)ICOO(-) decreased water spinach Vit C content. Furthermore, through uptake of I(-) and IO(-)(3). The nitrate content in water spinach was increased by different degrees.

Evergreen shrub traits and peatland carbon cycling under high nutrient load

NASA Astrophysics Data System (ADS)

Larmola, Tuula; Bui, Vi; Bubier, Jill L.; Wang, Meng; Murphy, Meaghan; Moore, Tim R.

2016-04-01

The reactive nitrogen (N) assimilated by plants is usually invested in chlorophyll to improve light harvesting capacity and in soluble proteins such as Rubisco to enhance carbon (C) assimilation. We studied the effects of simulated atmospheric N deposition on different traits of two evergreen shrubs Chamaedaphne calyculata and Rhododendron groenlandicum in a nutrient-poor Mer Bleue Bog, Canada that has been fertilized with N as NO3 and NH4 (2-8 times ambient annual wet deposition) with or without phosphorus (P) and potassium (K) for 7-12 years. We examined how nutrient addition influences the plant performance at leaf and canopy level and linked the trait responses with ecosystem C cycling. At the leaf level, we measured physiological and biochemical traits: CO2 exchange and chlorophyll fluorescence, an indicator of plant stress in terms of light harvesting capacity; and to study changes in photosynthetic nutrient use efficiency, we also determined the foliar chlorophyll, N, and P contents. At the canopy level, we examined morphological and phenological traits: growth responses and leaf longevity during two growing seasons. Regardless of treatment, the majority of leaves showed no signs of stress in terms of light harvesting capacity. The plants were N saturated: with increasing foliar N content, the higher proportion of N was not used in photosynthesis. Foliar net CO2 assimilation rates did not differ significantly among treatments, but the additions of N, P, and K together resulted in higher respiration rates. The analysis of the leaf and canopy traits showed that the two shrubs had different strategies: C. calyculata was more responsive to nutrient additions, more deciduous-like, whereas R. groenlandicum maintained evergreen features under nutrient load, shedding its leaves even later in the season. In all, simulated atmospheric N deposition did not benefit the photosynthetic apparatus of the dominant shrubs, but resulted in higher foliar respiration, contributing to stress and a weaker ecosystem C sink. Thus, elevated atmospheric deposition of nutrients to these systems may endanger C storage in peatlands.

Eutrophication effects on greenhouse gas fluxes from shallow-lake mesocosms override those of climate warming.

PubMed

Davidson, Thomas A; Audet, Joachim; Svenning, Jens-Christian; Lauridsen, Torben L; Søndergaard, Martin; Landkildehus, Frank; Larsen, Søren E; Jeppesen, Erik

2015-12-01

Fresh waters make a disproportionately large contribution to greenhouse gas (GHG) emissions, with shallow lakes being particular hot spots. Given their global prevalence, how GHG fluxes from shallow lakes are altered by climate change may have profound implications for the global carbon cycle. Empirical evidence for the temperature dependence of the processes controlling GHG production in natural systems is largely based on the correlation between seasonal temperature variation and seasonal change in GHG fluxes. However, ecosystem-level GHG fluxes could be influenced by factors, which while varying seasonally with temperature are actually either indirectly related (e.g. primary producer biomass) or largely unrelated to temperature, for instance nutrient loading. Here, we present results from the longest running shallow-lake mesocosm experiment which demonstrate that nutrient concentrations override temperature as a control of both the total and individual GHG flux. Furthermore, testing for temperature treatment effects at low and high nutrient levels separately showed only one, rather weak, positive effect of temperature (CH4 flux at high nutrients). In contrast, at low nutrients, the CO2 efflux was lower in the elevated temperature treatments, with no significant effect on CH4 or N2 O fluxes. Further analysis identified possible indirect effects of temperature treatment. For example, at low nutrient levels, increased macrophyte abundance was associated with significantly reduced fluxes of both CH4 and CO2 for both total annual flux and monthly observation data. As macrophyte abundance was positively related to temperature treatment, this suggests the possibility of indirect temperature effects, via macrophyte abundance, on CH4 and CO2 flux. These findings indicate that fluxes of GHGs from shallow lakes may be controlled more by factors indirectly related to temperature, in this case nutrient concentration and the abundance of primary producers. Thus, at ecosystem scale, response to climate change may not follow predictions based on the temperature dependence of metabolic processes. © 2015 John Wiley & Sons Ltd.

Growth impacts of Saharan dust, mineral nutrients, and CO2 on a planktonic herbivore in southern Mediterranean lakes.

PubMed

Villar-Argaiz, Manuel; Cabrerizo, Marco J; González-Olalla, Juan Manuel; Valiñas, Macarena S; Rajic, Sanja; Carrillo, Presentación

2018-05-17

Rising levels of CO 2 can boost plant biomass but reduce its quality as a food source for herbivores. However, significant uncertainties remain as to the degree to which the effect is modulated by other environmental factors and the underlying processes causing these responses in nature. To address these questions, we carried out CO 2 -manipulation experiments using natural seston from three lakes under nutrient-enriched conditions (mimicking eutrophication and atmospheric dust-input processes) as a food source for the planktonic Daphnia pulicaria. Contrary to expectations, there were no single effects of rising CO 2 on herbivorous growth. Instead, synergistic CO 2  × nutrient interactions indicated that CO 2 did not support higher zooplankton growth rates unless supplemented with dust or inorganic nutrients (nitrogen, N; phosphorus, P) in two of three studied lakes. The overall positive correlation between zooplankton growth and seston carbon (C), but not seston C:P, suggested that this was a food quantity-mediated response. In addition, we found that this correlation improved when the data were grouped according to the nutrient treatments, and that the response was largest for dust. The synergistic CO 2  × nutrient effects reported here imply that the effects of rising CO 2 levels on herbivorous growth may be strongly influenced by eutrophication processes and the increase in dust deposition predicted for the Mediterranean region. Copyright © 2018 Elsevier B.V. All rights reserved.

Are functional foods redefining nutritional requirements?

PubMed

Jones, Peter J; Varady, Krista A

2008-02-01

Functional foods are increasing in popularity owing to their ability to confer health and physiological benefits. Nevertheless, the notion that functional foods improve health when providing nutrients at levels above and beyond existing recommended intakes is inconsistent with the definition of requirement. This disparity highlights the need for an alternative definition of nutrient requirement. The present objective is to examine distinctions between optimization of health, as defined by what we currently deem as required intakes, versus adding physiological benefit using bioactive agents found in functional foods. Presently, requirement is defined as the lowest amount of intake of a nutrient that will maintain a defined level of nourishment for a specific indicator of adequacy. In contrast, functional foods are described as ingredients that are not necessary for body function, yet provide added physiological benefit that confer better overall health. Plant sterols are one example of such an ingredient. Plant sterols lower plasma cholesterol concentrations, and may thus be considered essential nutrients in physiological situations where circulating cholesterol concentrations are high. Similarly, intakes of omega-3 fats beyond existing requirement may confer additional health benefits such as hypolipidemic and anti-diabetic effects. These examples underscore the inconsistencies between what is defined as a nutrient requirement versus what is identified as a health benefit of a functional food. Such discrepancies emphasize the need for a more all-encompassing definition of a nutrient requirement; that is, one that moves beyond the prevention of overt deficiency to encompass improved health and disease risk reduction.

Effects of feeding level on nutrient digestibility and enteric methane production in growing goats (Capra hircus hircus) and Sika deer (Cervus nippon hortulorum).

PubMed

Na, Youngjun; Li, Dong Hua; Choi, Yongjun; Kim, Kyoung Hoon; Lee, Sang Rak

2018-03-02

Two experiments were conducted to determine the effects of feeding level on nutrient digestibility and enteric methane (CH4) emissions in growing goats and Sika deer. Three growing male goats (initial BW of 22.4 ± 0.9 kg) and three growing male deer (initial BW of 20.2 ± 4.8 kg) were each allotted to a respiration-metabolism chamber for an adaptation period of 7 d and a data collection period of 3 d. An experimental diet was offered to each animal at one of three feeding levels (1.5, 2.0, and 2.5% of BW) in a 3 × 3 Latin square design. The chambers were used for measuring enteric CH4 emission. Nutrient digestibility decreased linearly in goats as feeding level increased, whereas Sika deer digestibility was not affected by feeding level. The enteric production of CH4 expressed as g/kg DMI, g/kg organic matter intake (OMI), and % of gross energy intake (GEI) decreased linearly with increased feeding level in goats; however, that of Sika deer was not affected by feeding level. Six equations were estimated for predicting the enteric CH4 emission from goats and Sika deer. For goat, equation 1 was found to be of the highest accuracy: CH4 (g/day) = 6.2 (± 14.1) + 10.2 (± 7.01) × DMI (kg/day) + 0.0048 (± 0.0275) × DMD (g/kg) - 0.0070 (± 0.0187) × neutral detergent fiber digestibility (NDFD; g/kg). For Sika deer, equation 4 was found to be of the highest accuracy: CH4 (g/day) = - 13.0 (± 30.8) + 29.4 (± 3.93) × DMI (kg/day) + 0.046 (± 0.094) × DMD (g/kg) - 0.0363 (± 0.0636) × NDFD (g/kg). Increasing the feeding level increased CH4 production in both goats and Sika deer, and predictive models of enteric CH4 production by goats and Sika deer were estimated.

The immune system: a target for functional foods?

PubMed

Calder, Philip C; Kew, Samantha

2002-11-01

The immune system acts to protect the host from infectious agents that exist in the environment (bacteria, viruses, fungi, parasites) and from other noxious insults. The immune system is constantly active, acting to discriminate 'non-self' from 'self'. The immune system has two functional divisions: the innate and the acquired. Both components involve various blood-borne factors (complement, antibodies, cytokines) and cells. A number of methodologies exist to assess aspects of immune function; many of these rely upon studying cells in culture ex vivo. There are large inter-individual variations in many immune functions even among the healthy. Genetics, age, gender, smoking habits, habitual levels of exercise, alcohol consumption, diet, stage in the female menstrual cycle, stress, history of infections and vaccinations, and early life experiences are likely to be important contributors to the observed variation. While it is clear that individuals with immune responses significantly below 'normal' are more susceptible to infectious agents and exhibit increased infectious morbidity and mortality, it is not clear how the variation in immune function among healthy individuals relates to variation in susceptibility to infection. Nutrient status is an important factor contributing to immune competence: undernutrition impairs the immune system, suppressing immune functions that are fundamental to host protection. Undernutrition leading to impairment of immune function can be due to insufficient intake of energy and macronutrients and/or due to deficiencies in specific micronutrients. Often these occur in combination. Nutrients that have been demonstrated (in either animal or human studies) to be required for the immune system to function efficiently include essential amino acids, the essential fatty acid linoleic acid, vitamin A, folic acid, vitamin B6, vitamin B12, vitamin C, vitamin E, Zn, Cu, Fe and Se. Practically all forms of immunity may be affected by deficiencies in one or more of these nutrients. Animal and human studies have demonstrated that adding the deficient nutrient back to the diet can restore immune function and resistance to infection. Among the nutrients studied most in this regard are vitamin E and Zn. Increasing intakes of some nutrients above habitual and recommended levels can enhance some aspects of immune function. However, excess amounts of some nutrients also impair immune function. There is increasing evidence that probiotic bacteria improve host immune function. The effect of enhancing immune function on host resistance to infection in healthy individuals is not clear.

Smokers report lower intake of key nutrients than nonsmokers, yet both fall short of meeting recommended intakes.

PubMed

Raatz, Susan K; Jahns, Lisa; Johnson, LuAnn K; Scheett, Angela; Carriquiry, Alicia; Lemieux, Andrine; Nakajima, Motohiro; al'Absi, Mustafa

2017-09-01

Smoking is a major risk factor in the development of preventable disease which may be due to a poorer diet and the reduced nutrient intake of smokers. Our objective was to compare and evaluate the reported intake of current smokers with that of nonsmokers among participants of a study evaluating stress and smoking. We hypothesized (1) that overall energy and nutrient intake would be reduced in smokers compared with nonsmokers and (2) that smokers would have increased noncompliance with Dietary Reference Intakes (DRIs). Men and women (smokers n=138, nonsmokers n=46) completed a 3-day diet record at baseline. Mean energy and nutrient intakes were stratified by smoking status and compared with DRI levels. The mean body mass index was 28.3±0.5kg/m 2 for smokers and 27.2±1.0kg/m 2 for nonsmokers. Compared with nonsmokers, the smokers reported lower intakes of energy, total polyunsaturated fatty acids, linolenic acid, docosahexaenoic acid, total sugars, calcium, iron, magnesium, phosphorus, potassium, vitamin C, riboflavin, niacin, pantothenic acid, vitamin B6, folate, vitamin A, and vitamin E. Smokers reported reduced compliance with the DRIs for iron, phosphorus, vitamin C, riboflavin, and folate compared with nonsmokers. Unlike other evaluations of smokers vs nonsmokers, we observed no difference in body weight between groups. Smokers and nonsmokers alike reported dietary intakes lower than the DRIs for many nutrients. However, the reported nutrient intake of the smokers was substantially lower than nonsmokers for key nutrients, and they were more likely to not comply with the DRIs for essential nutrients, placing them at increased risk of chronic disease. Published by Elsevier Inc.

Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil.

PubMed

Sutton, Nora B; Grotenhuis, Tim; Rijnaarts, Huub H M

2014-02-01

Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton's reagent and modified Fenton's reagent coupled with a subsequent bioremediation phase of 187d, both with and without nutrient amendment. Chemical oxidation mobilized SOM into the liquid phase, producing dissolved organic carbon (DOC) concentrations 8-16 times higher than the untreated field sample. Higher aqueous concentrations of nitrogen and phosphorous species were also observed following oxidation; NH4(+) increased 14-172 times. During the bioremediation phase, dissolved carbon and nutrient species were utilized for microbial growth-yielding DOC concentrations similar to field sample levels within 56d of incubation. In the absence of nutrient amendment, the highest microbial respiration rates were correlated with higher availability of nitrogen and phosphorus species mobilized by oxidation. Significant diesel degradation was only observed following nutrient amendment, implying that nutrients mobilized by chemical oxidation can increase microbial activity but are insufficient for bioremediation. While all bioremediation occurred in the first 28d of incubation in the biotic control microcosm with nutrient amendment, biodegradation continued throughout 187d of incubation following chemical oxidation, suggesting that chemical treatment also affects the desorption of organic contaminants from SOM. Overall, results indicate that biodegradation of DOC, as an alternative substrate to diesel, and biological utilization of mobilized nutrients have implications for the success of coupled ISCO and ISB treatments. Copyright © 2013 Elsevier Ltd. All rights reserved.

MicroRNA-124 expression counteracts pro-survival stress responses in glioblastoma.

PubMed

Mucaj, V; Lee, S S; Skuli, N; Giannoukos, D N; Qiu, B; Eisinger-Mathason, T S K; Nakazawa, M S; Shay, J E S; Gopal, P P; Venneti, S; Lal, P; Minn, A J; Simon, M C; Mathew, L K

2015-04-23

Glioblastomas are aggressive adult brain tumors, characterized by inadequately organized vasculature and consequent nutrient and oxygen (O2)-depleted areas. Adaptation to low nutrients and hypoxia supports glioblastoma cell survival, progression and therapeutic resistance. However, specific mechanisms promoting cellular survival under nutrient and O2 deprivation remain incompletely understood. Here, we show that miR-124 expression is negatively correlated with a hypoxic gene signature in glioblastoma patient samples, suggesting that low miR-124 levels contribute to pro-survival adaptive pathways in this disease. As miR-124 expression is repressed in various cancer types (including glioblastoma), we quantified miR-124 abundance in normoxic and hypoxic regions in glioblastoma patient tissue, and investigated whether ectopic miR-124 expression compromises cell survival during tumor ischemia. Our results indicate that miR-124 levels are further diminished in hypoxic/ischemic regions within individual glioblastoma patient samples, compared with regions replete in O2 and nutrients. Importantly, we also show that increased miR-124 expression affects the ability of tumor cells to survive under O2 and/or nutrient deprivation. Moreover, miR-124 re-expression increases cell death in vivo and enhances the survival of mice bearing intracranial xenograft tumors. miR-124 exerts this phenotype in part by directly regulating TEAD1, MAPK14/p38α and SERP1, factors involved in cell proliferation and survival under stress. Simultaneous suppression of these miR-124 targets results in similar levels of cell death as caused by miR-124 restoration. Importantly, we further demonstrate that SERP1 reintroduction reverses the hypoxic cell death elicited by miR-124, indicating the importance of SERP1 in promoting tumor cell survival. In support of our experimental data, we observed a significant correlation between high SERP1 levels and poor patient outcome in glioblastoma patients. Collectively, among the many pro-tumorigeneic properties of miR-124 repression in glioblastoma, we delineated a novel role in promoting tumor cell survival under stressful microenvironments, thereby supporting tumor progression.

MicroRNA-124 expression counteracts pro-survival stress responses in glioblastoma

PubMed Central

Mucaj, Vera; Lee, Samuel S.; Skuli, Nicolas; Giannoukos, Dionysios N.; Qiu, Bo; Eisinger-Mathason, T.S. Karin; Nakazawa, Michael S.; Shay, Jessica E.S.; Gopal, Pallavi P.; Venneti, Sriram; Lal, Priti; Minn, Andy J.; Simon, M. Celeste; Mathew, Lijoy K.

2014-01-01

Glioblastomas are aggressive adult brain tumors, characterized by inadequately organized vasculature and consequent nutrient and oxygen (O2)-depleted areas. Adaptation to low nutrients and hypoxia supports glioblastoma cell survival, progression, and therapeutic resistance. However, specific mechanisms promoting cellular survival under nutrient and O2 deprivation remain incompletely understood. Here, we show that miR-124 expression is negatively correlated with a hypoxic gene signature in glioblastoma patient samples, suggesting that low miR-124 levels contribute to pro-survival adaptive pathways in this disease. Since miR-124 expression is repressed in various cancers (including glioblastoma), we quantified miR-124 abundance in normoxic and hypoxic regions in glioblastoma patient tissue, and investigated whether ectopic miR-124 expression compromises cell survival, during tumor ischemia. Our results indicate that miR-124 levels are further diminished in hypoxic/ischemic regions within individual glioblastoma patient samples, compared to regions replete in O2 and nutrients. Importantly, we also show that increased miR-124 expression affects the ability of tumor cells to survive under O2 and/or nutrient deprivation. Moreover, miR-124 re-expression increases cell death in vivo, and enhances the survival of mice bearing intracranial xenograft tumors. miR-124 exerts this phenotype in part by directly regulating TEAD1, MAPK14/p38α and SERP1, factors involved in cell proliferation and survival under stress. Simultaneous suppression of these miR-124 targets results in similar levels of cell death as caused by miR-124 restoration. Importantly, we further demonstrate that SERP1 re-introduction reverses the hypoxic cell death elicited by miR-124, indicating the importance of SERP1 in promoting tumor cell survival. In support of our experimental data, we observed a significant correlation between high SERP1 levels and poor patient outcome in glioblastoma patients. Collectively, among the many pro-tumorigeneic properties of miR-124 repression in glioblastoma, we delineated a novel role in promoting tumor cell survival under stressful microenvironments, thereby supporting tumor progression. PMID:24954504

Nutrient losses from timber harvesting in a larch/ Douglas-fir forest

Treesearch

Nellie M. Stark

1979-01-01

Nutrient levels as a result of experimental clearcutting, shelterwood cutting, and group selection cutting - each with three levels of harvesting intensity - were studied in a larchfir forest in northwest Montana, experimentally logged with a skyline system. None of the treatments altered nutrient levels in an intermittent stream, nor were excessive amounts of...

Nanotechnology in Sustainable Agriculture: Recent Developments, Challenges, and Perspectives

PubMed Central

Prasad, Ram; Bhattacharyya, Atanu; Nguyen, Quang D.

2017-01-01

Nanotechnology monitors a leading agricultural controlling process, especially by its miniature dimension. Additionally, many potential benefits such as enhancement of food quality and safety, reduction of agricultural inputs, enrichment of absorbing nanoscale nutrients from the soil, etc. allow the application of nanotechnology to be resonant encumbrance. Agriculture, food, and natural resources are a part of those challenges like sustainability, susceptibility, human health, and healthy life. The ambition of nanomaterials in agriculture is to reduce the amount of spread chemicals, minimize nutrient losses in fertilization and increased yield through pest and nutrient management. Nanotechnology has the prospective to improve the agriculture and food industry with novel nanotools for the controlling of rapid disease diagnostic, enhancing the capacity of plants to absorb nutrients among others. The significant interests of using nanotechnology in agriculture includes specific applications like nanofertilizers and nanopesticides to trail products and nutrients levels to increase the productivity without decontamination of soils, waters, and protection against several insect pest and microbial diseases. Nanotechnology may act as sensors for monitoring soil quality of agricultural field and thus it maintain the health of agricultural plants. This review covers the current challenges of sustainability, food security and climate change that are exploring by the researchers in the area of nanotechnology in the improvement of agriculture. PMID:28676790

Nanotechnology in Sustainable Agriculture: Recent Developments, Challenges, and Perspectives.

PubMed

Prasad, Ram; Bhattacharyya, Atanu; Nguyen, Quang D

2017-01-01

Nanotechnology monitors a leading agricultural controlling process, especially by its miniature dimension. Additionally, many potential benefits such as enhancement of food quality and safety, reduction of agricultural inputs, enrichment of absorbing nanoscale nutrients from the soil, etc. allow the application of nanotechnology to be resonant encumbrance. Agriculture, food, and natural resources are a part of those challenges like sustainability, susceptibility, human health, and healthy life. The ambition of nanomaterials in agriculture is to reduce the amount of spread chemicals, minimize nutrient losses in fertilization and increased yield through pest and nutrient management. Nanotechnology has the prospective to improve the agriculture and food industry with novel nanotools for the controlling of rapid disease diagnostic, enhancing the capacity of plants to absorb nutrients among others. The significant interests of using nanotechnology in agriculture includes specific applications like nanofertilizers and nanopesticides to trail products and nutrients levels to increase the productivity without decontamination of soils, waters, and protection against several insect pest and microbial diseases. Nanotechnology may act as sensors for monitoring soil quality of agricultural field and thus it maintain the health of agricultural plants. This review covers the current challenges of sustainability, food security and climate change that are exploring by the researchers in the area of nanotechnology in the improvement of agriculture.

Effects of warming and nutrients on the microbial food web in shallow lake mesocosms.

PubMed

Zingel, Priit; Cremona, Fabien; Nõges, Tiina; Cao, Yu; Neif, Érika M; Coppens, Jan; Işkın, Uğur; Lauridsen, Torben L; Davidson, Thomas A; Søndergaard, Martin; Beklioglu, Meryem; Jeppesen, Erik

2018-06-01

We analysed changes in the abundance, biomass and cell size of the microbial food web community (bacteria, heterotrophic nanoflagellates, ciliates) at contrasting nutrient concentrations and temperatures during a simulated heat wave. We used 24 mesocosms mimicking shallow lakes in which two nutrient levels (unenriched and enriched by adding nitrogen and phosphorus) and three different temperature scenarios (ambient, IPCC A2 scenario and A2+%50) are simulated (4 replicates of each). Experiments using the mesocosms have been running un-interrupted since 2003. A 1-month heat wave was imitated by an extra 5 °C increase in the previously heated mesocosms (from 1st July to 1st August 2014). Changes in water temperature induced within a few days a strong effect on the microbial food web functioning, demonstrating a quick response of microbial communities to the changes in environment, due to their short generation times. Warming and nutrients showed synergistic effects. Microbial assemblages of heterotrophic nanoflagellates and ciliates responded positively to the heating, the increase being largest in the enriched mesocosms. The results indicate that warming and nutrients in combination can set off complex interactions in the microbial food web functioning. Copyright © 2018 Elsevier GmbH. All rights reserved.

Eating increases oxidative damage in a reptile.

PubMed

Butler, Michael W; Lutz, Thomas J; Fokidis, H Bobby; Stahlschmidt, Zachary R

2016-07-01

While eating has substantial benefits in terms of both nutrient and energy acquisition, there are physiological costs associated with digesting and metabolizing a meal. Frequently, these costs have been documented in the context of energy expenditure while other physiological costs have been relatively unexplored. Here, we tested whether the seemingly innocuous act of eating affects either systemic pro-oxidant (reactive oxygen metabolite, ROM) levels or antioxidant capacity of corn snakes (Pantherophis guttatus) by collecting plasma during absorptive (peak increase in metabolic rate due to digestion of a meal) and non-absorptive (baseline) states. When individuals were digesting a meal, there was a minimal increase in antioxidant capacity relative to baseline (4%), but a substantial increase in ROMs (nearly 155%), even when controlling for circulating nutrient levels. We report an oxidative cost of eating that is much greater than that due to long distance flight or mounting an immune response in other taxa. This result demonstrates the importance of investigating non-energetic costs associated with meal processing, and it begs future work to identify the mechanism(s) driving this increase in ROM levels. Because energetic costs associated with eating are taxonomically widespread, identifying the taxonomic breadth of eating-induced ROM increases may provide insights into the interplay between oxidative damage and life history theory. © 2016. Published by The Company of Biologists Ltd.

Intake, Nutrient Apparent Digestibility, and Ruminal Constituents of Crossbred Dorper × Santa Inês Sheep Fed Diets with Babassu Mesocarp Flour

PubMed Central

Gerude Neto, Osman José de Aguiar; Parente, Michelle de Oliveira Maia; Alves, Arnaud Azevedo; dos Santos, Paull Andrews Carvalho; Moreira Filho, Miguel Arcanjo; Bezerra, Leilson Rocha; Gomes, Ruan Mourão da Silva

2016-01-01

The aim of this study was to evaluate the effect on intake, apparent digestibility, and ruminal constituents of sheep in response to the addition of increasing levels of babassu mesocarp flour (BMF) to the diet. Twenty crossbred sheep (29.17 ± 2.23 kg) were used in a randomized complete block design. Lambs were confined for 21 days, with 16 days for diet adaptation and 5 days for data collection, in which they were fed an isonitrogenous diet (16.5 ± 0.2 CP, DM basis) containing 70% of concentrate and 30% (DM basis) of Tifton 85 hay. Increasing levels of BMF were 0, 10, 20, and 30% (DM basis). There was a quadratic effect (P < 0.05) on the DM intake, nutrients intake, and digestibility of CP and NFC. The digestibility of DM, OM, TC, and NDF decreased linearly, while EE digestibility increased linearly with increasing levels of BMF. The high NDF content presented in the chemical composition of the babassu mesocarp flour ranked the same as fibrous food, which can limit the inclusion in the diet of high production animals. So, babassu mesocarp flour is an alternative for energy source in lambs feed and can be added at levels up to 10%. PMID:27957525

Isolation and characterization of N2 -fixing bacteria from giant reed and switchgrass for plant growth promotion and nutrient uptake.

PubMed

Xu, Jia; Kloepper, Joseph W; Huang, Ping; McInroy, John A; Hu, Chia H

2018-05-01

The aims of this study were to isolate and characterize N 2 -fixing bacteria from giant reed and switchgrass and evaluate their plant growth promotion and nutrient uptake potential for use as biofertilizers. A total of 190 bacteria were obtained from rhizosphere soil and inside stems and roots of giant reed and switchgrass. All the isolates were confirmed to have nitrogenase activity, 96.9% produced auxin, and 85% produced siderophores. Then the top six strains, including Sphingomonas trueperi NNA-14, Sphingomonas trueperi NNA-19, Sphingomonas trueperi NNA-17, Sphingomonas trueperi NNA-20, Psychrobacillus psychrodurans NP-3, and Enterobacter oryzae NXU-38, based on nitrogenase activity, were inoculated on maize and wheat seeds in greenhouse tests to assess their potential benefits to plants. All the selected strains promoted plant growth by increasing at least one plant growth parameter or increasing the nutrient concentration of maize or wheat plants. NNA-14 outperformed others in promoting early growth and nutrient uptake by maize. Specifically, NNA-14 significantly increased root length, surface area, and fine roots of maize by 14%, 12%, and 17%, respectively, and enhanced N, Ca, S, B, Cu, and Zn in maize. NNA-19 and NXU-38 outperformed others in promoting both early growth and nutrient uptake by wheat. Specifically, NNA-19 significantly increased root dry weight and number of root tips of wheat by 25% and 96%, respectively, and enhanced Ca in wheat. NXU-38 significantly increased root length, surface area, and fine roots of wheat by 21%, 13%, and 26%, respectively, and enhanced levels of Ca and Mg in wheat. It is concluded that switchgrass and giant reed are colonized by N 2 -fixing bacteria that have the potential to contribute to plant growth and nutrient uptake by agricultural crops. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distribution and variability of nitrogen and phosphorus in the alluvial, High Plains, Rush Springs, and Blaine aquifers in western Oklahoma

USGS Publications Warehouse

Becker, C.J.

1994-01-01

Aquifers are the primary source of water for drinking and agricultural purposes in western Oklahoma. Health concerns about consuming nitrogen and an increased reliance on ground water for drinking necessitate a better understanding of the cause and effect of contamination from nutrients. The purpose of this project was to compile nutrients data from the National Water Information System data base for the alluvial aquifers west of longitude 98 degrees W. and from three bedrock aquifers, High Plains, Rush Springs, and Blaine, and provide this information in a report for future projects and for the facilitation of nutrient source management. The scope of the work consisted of (1) compiling ground-water quality data concerning nitrogen and phosphorus ions, (2) constructing boxplots illustrating data variability, (3) maps for each aquifer showing locations of wells when nitrogen and phosphorus ions were measured in ground water and where concentrations of nitrate and nitrite, reported as nitrogen, exceed the maximum contaminant level, and (4) calculating summary statistics. Nutrient data were obtained from the U.S. Geological Survey data base called the National Water Information System. Data were restricted to ground-water samples, but no restrictions were placed on well and water use or date and time of sampling. Compiled nutrient data consist of dissolved and total concentrations of the common nitrogen and phosphorus ions measured in ground water. For nitrogen these ions include nitrate, nitrite, ammonium, and nitrite plus nitrate. All concentrations are reported in milligrams per liter as nitrogen. Phosphorus in ground water is measured as the orthophosphate ion, and is reported in milligrams per liter as phosphorus. Nutrient variability is illustrated by a standard boxplot. The data are presented by aquifer or hydrologic subregion for alluvial aquifers, with one boxplot constructed for each nutrient compound if more than four analyses are present. Maps for each aquifer show where nitrogen and phosphorus have been measured in ground water and where the concentrations of nitrate and nitrite exceed the maximum contaminant level. A statistical summary for each aquifer and subregion show if censored data were present, number of samples in each data set, largest minimum reporting level for each nutrient compound, percentiles used to construct boxplots, and minimum and maximum values. Also given are the number of wells sampled in each aquifer and the number of wells exceeding the maximum contaminant level.

Impacts of fertilization on water quality of a drained pine plantation: a worst case scenario.

PubMed

Beltran, Bray J; Amatya, Devendra M; Youssef, Mohamed; Jones, Martin; Callahan, Timothy J; Skaggs, R Wayne; Nettles, Jami E

2010-01-01

Intensive plantation forestry will be increasingly important in the next 50 yr to meet the high demand for domestic wood in the United States. However, forest management practices can substantially influence downstream water quality and ecology. This study analyses, the effect of fertilization on effluent water quality of a low gradient drained coastal pine plantation in Carteret County, North Carolina using a paired watershed approach. The plantation consists of three watersheds, two mature (31-yr) and one young (8-yr) (age at treatment). One of the mature watersheds was commercially thinned in 2002. The mature unthinned watershed was designated as the control. The young and mature-thinned watersheds were fertilized at different rates with Arborite (Encee Chemical Sales, Inc., Bridgeton, NC), and boron. The outflow rates and nutrient concentrations in water drained from each of the watersheds were measured. Nutrient concentrations and loadings were analyzed using general linear models (GLM). Three large storm events occurred within 47 d of fertilization, which provided a worst case scenario for nutrient export from these watersheds to the receiving surface waters. Results showed that average nutrient concentrations soon after fertilization were significantly (alpha = 0.05) higher on both treatment watersheds than during any other period during the study. This increase in nutrient export was short lived and nutrient concentrations and loadings were back to prefertilization levels as soon as 3 mo after fertilization. Additionally, the mature-thinned watershed presented higher average nutrient concentrations and loadings when compared to the young watershed, which received a reduced fertilizer rate than the mature-thinned watershed.

Phosphorylated Akt Protein at Ser473 Enables HeLa Cells to Tolerate Nutrient-Deprived Conditions

PubMed

Fathy, Moustafa; Awale, Suresh; Nikaido, Toshio

2017-12-29

Background: Despite angiogenesis, many tumours remain hypovascular and starved of nutrients while continuing to grow rapidly. The specific biochemical mechanisms associated with starvation resistance, austerity, may be new biological characters of cancer that are critical for cancer progression. Objective: This study aim was to investigate the effect of nutrient starvation on HeLa cells and the possible mechanism by which the cells are able to tolerate nutrient-deprived conditions. Methods: Nutrient starvation was achieved by culturing HeLa cells in nutrient-deprived medium (NDM) and cell survival was estimated by using cell counting kit-8. The effect of starvation on cell cycle distribution and the quantitative analysis of apoptotic cells were investigated by flow cytometry using propidium iodide staining. Western blotting was used to detect the expression levels of Akt and phosphorylated Akt at Ser473 (Ser473p-Akt) proteins. Results: HeLa cells displayed extremely long survival when cultured in NDM. The percentage of apoptotic HeLa cells was significantly increased by starvation in a time-dependent manner. A significant increase in the expression of Ser473p-Akt protein after starvation was also observed. Furthermore, it was found that Akt inhibitor III molecule inhibited the cells proliferation in a concentration- and time-dependent manner. Conclusion: Results of the present study provide evidence that Akt activation may be implicated in the tolerance of HeLa cells for nutrient starvation and may help to suggest new therapeutic strategies designed to prevent austerity of cervical cancer cells through inhibition of Akt activation. Creative Commons Attribution License

Seasonal Changes of Bioluminescence in Photosynthetic and Heterotrophic Dinoflagellates at San Clemente Island

DTIC Science & Technology

2012-02-01

were calculated using n-2 degrees of freedom. 2.2 Nutrient and chlorophyll data Nitrate and Chl a levels were obtained from archived CalCOFI data...a later increase in photosynthetic biomass in the fall. However, Chl a levels were actually low during the period when bioluminescence was high and...for 1994-1995 which may suggest that as Chl a levels increased, so did bioluminescence cell-1 (Figure 7c). These field measurements support previous

Constraints and opportunities for implementing nutrition-specific, agricultural and market-based approaches to improve nutrient intake adequacy among infants and young children in two regions of rural Kenya.

PubMed

Hotz, Christine; Pelto, Gretel; Armar-Klemesu, Margaret; Ferguson, Elaine F; Chege, Peter; Musinguzi, Enock

2015-12-01

Several types of interventions can be used to improve nutrient intake adequacy in infant and young child (IYC) diets, including fortified foods, home fortification, nutrition education and behaviour change communication (BCC) in addition to agricultural and market-based strategies. However, the appropriate selection of interventions depends on the social, cultural, physical and economic context of the population. Derived from two rural Kenyan populations, this analysis combined information from: (1) a quantitative analysis to derive a set of food-based recommendations (FBRs) to fill nutrient intake gaps in IYC diets and identify 'problem nutrients' for which intake gaps require solutions beyond currently available foods and dietary patterns, and (2) an ethnographic qualitative analysis to identify contextual factors posing opportunities or constraints to implementing the FBRs, including perceptions of cost, convenience, accessibility and appropriateness of the recommended foods for IYC diets and other social or physical factors that determine accessibility of those foods. Opportunities identified included BCC to increase the acceptability and utilisation of green leafy vegetables (GLV) and small fish and agronomic interventions to increase the productivity of GLV and millet. Value chains for millet, beans, GLV, milk and small fish should be studied for opportunities to increase their accessibility in local markets. Processor-level interventions, such as partially cooked fortified dry porridge mixes or unfortified cereal mixes incorporating millet and beans, may increase the accessibility of foods that provide increased amounts of the problem nutrients. Multi-sectoral actors and community stakeholders should be engaged to assess the feasibility of implementing these locally appropriate strategies. © 2015 John Wiley & Sons Ltd.

Linkages Between Nutrients and Assemblages of Macroinvertebrates and Fish in Wadeable Streams: Implication to Nutrient Criteria Development

NASA Astrophysics Data System (ADS)

Wang, Lizhu; Robertson, Dale M.; Garrison, Paul J.

2007-02-01

We sampled 240 wadeable streams across Wisconsin for different forms of phosphorus and nitrogen, and assemblages of macroinvertebrates and fish to (1) examine how macroinvertebrate and fish measures correlated with the nutrients; (2) quantify relationships between key biological measures and nutrient forms to identify potential threshold levels of nutrients to support nutrient criteria development; and (3) evaluate the importance of nutrients in influencing biological assemblages relative to other physicochemical factors at different spatial scales. Twenty-three of the 35 fish and 18 of the 26 macroinvertebrate measures significantly correlated ( P < 0.05) with at least one nutrient measure. Percentages of carnivorous, intolerant, and omnivorous fishes, index of biotic integrity, and salmonid abundance were fish measures correlated with the most nutrient measures and had the highest correlation coefficients. Percentages of Ephemeroptera-Plecoptera-Trichoptera individuals and taxa, Hilsenhoff biotic index, and mean tolerance value were macroinvertebrate measures that most strongly correlated with the most nutrient measures. Selected biological measures showed clear trends toward degradation as concentrations of phosphorus and nitrogen increased, and some measures showed clear thresholds where biological measures changed drastically with small changes in nutrient concentrations. Our selected environmental factors explained 54% of the variation in the fish assemblages. Of this explained variance, 46% was attributed to catchment and instream habitat, 15% to nutrients, 3% to other water quality measures, and 36% to the interactions among all the environmental variables. Selected environmental factors explained 53% of the variation in macroinvertebrate assemblages. Of this explained variance, 42% was attributed to catchment and instream habitat, 22% to nutrients, 5% to other water quality measures, and 32% to the interactions among all the environmental variables.

Linkages between nutrients and assemblages of macroinvertebrates and fish in wadeable streams: Implication to nutrient criteria development

USGS Publications Warehouse

Wang, L.; Robertson, Dale M.; Garrison, P.J.

2007-01-01

We sampled 240 wadeable streams across Wisconsin for different forms of phosphorus and nitrogen, and assemblages of macroinvertebrates and fish to (1) examine how macroinvertebrate and fish measures correlated with the nutrients; (2) quantify relationships between key biological measures and nutrient forms to identify potential threshold levels of nutrients to support nutrient criteria development; and (3) evaluate the importance of nutrients in influencing biological assemblages relative to other physicochemical factors at different spatial scales. Twenty-three of the 35 fish and 18 of the 26 macroinvertebrate measures significantly correlated (P < 0.05) with at least one nutrient measure. Percentages of carnivorous, intolerant, and omnivorous fishes, index of biotic integrity, and salmonid abundance were fish measures correlated with the most nutrient measures and had the highest correlation coefficients. Percentages of Ephemeroptera-Plecoptera-Trichoptera individuals and taxa, Hilsenhoff biotic index, and mean tolerance value were macroinvertebrate measures that most strongly correlated with the most nutrient measures. Selected biological measures showed clear trends toward degradation as concentrations of phosphorus and nitrogen increased, and some measures showed clear thresholds where biological measures changed drastically with small changes in nutrient concentrations. Our selected environmental factors explained 54% of the variation in the fish assemblages. Of this explained variance, 46% was attributed to catchment and instream habitat, 15% to nutrients, 3% to other water quality measures, and 36% to the interactions among all the environmental variables. Selected environmental factors explained 53% of the variation in macroinvertebrate assemblages. Of this explained variance, 42% was attributed to catchment and instream habitat, 22% to nutrients, 5% to other water quality measures, and 32% to the interactions among all the environmental variables. ?? 2006 Springer Science+Business Media, Inc.

Regulation of GPR119 receptor activity with endocannabinoid-like lipids.

PubMed

Syed, Samreen K; Bui, Hai Hoang; Beavers, Lisa S; Farb, Thomas B; Ficorilli, James; Chesterfield, Amy K; Kuo, Ming-Shang; Bokvist, Krister; Barrett, David G; Efanov, Alexander M

2012-12-15

The GPR119 receptor plays an important role in the secretion of incretin hormones in response to nutrient consumption. We have studied the ability of an array of naturally occurring endocannabinoid-like lipids to activate GPR119 and have identified several lipid receptor agonists. The most potent receptor agonists identified were three N-acylethanolamines: oleoylethanolamine (OEA), palmitoleoylethanolamine, and linoleylethanolamine (LEA), all of which displayed similar potency in activating GPR119. Another lipid, 2-oleoylglycerol (2-OG), also activated GPR119 receptor but with significantly lower potency. Endogenous levels of endocannabinoid-like lipids were measured in intestine in fasted and refed mice. Of the lipid GPR119 agonists studied, the intestinal levels of only OEA, LEA, and 2-OG increased significantly upon refeeding. Intestinal levels of OEA and LEA in the fasted mice were low. In the fed state, OEA levels only moderately increased, whereas LEA levels rose drastically. 2-OG was the most abundant of the three GPR119 agonists in intestine, and its levels were radically elevated in fed mice. Our data suggest that, in lean mice, 2-OG and LEA may serve as physiologically relevant endogenous GPR119 agonists that mediate receptor activation upon nutrient uptake.

Does microbial biomass affect pelagic ecosystem efficiency? An experimental study.

PubMed

Wehr, J D; Le, J; Campbell, L

1994-01-01

Bacteria and other microorganisms in the pelagic zone participate in the recycling of organic matter and nutrients within the water column. The microbial loop is thought to enhance ecosystem efficiency through rapid recycling and reduced sinking rates, thus reducing the loss of nutrients contained in organisms remaining within the photic zone. We conducted experiments with lake communities in 5400-liter mesocosms, and measured the flux of materials and nutrients out of the water column. A factorial design manipulated 8 nutrient treatments: 4 phosphorus levels × 2 nitrogen levels. Total sedimentation rates were greatest in high-N mesocosms; within N-surplus communities, [Symbol: see text]1 µM P resulted in 50% increase in total particulate losses. P additions without added N had small effects on nutrient losses from the photic zone; +2 µM P tanks received 334 mg P per tank, yet after 14 days lost only 69 mg more particulate-P than did control communities. Nutrient treatments resulted in marked differences in phytoplankton biomass (twofold N effect, fivefold P effect in +N mesocosms only), bacterioplankton densities (twofold N-effect, twofold P effects in -N and +N mesocosms), and the relative importance of autotrophic picoplankton (maximum in high NY mesocosms). Multiple regression analysis found that of 8 plankton and water chemistry variables, the ratio of autotrophic picoplankton to total phytoplankton (measured as chlorophyll α) explained the largest portion of the total variation in sedimentation loss rates (65% of P-flux, 57% of N-flux, 26% of total flux). In each case, systems with greater relative importance of autotrophic picoplankton had significantly reduced loss rates. In contrast, greater numbers of planktonic bacteria were associated with increased sedimentation rates and lower system efficiency. We suggest that different microbial components may have contrasting effects on the presumed enhanced efficiency provided by the microbial loop.

Phytoplankton Assemblage Characteristics in Recurrently Fluctuating Environments

PubMed Central

Roelke, Daniel L.; Spatharis, Sofie

2015-01-01

Annual variations in biogeochemical and physical processes can lead to nutrient variability and seasonal patterns in phytoplankton productivity and assemblage structure. In many coastal systems river inflow and water exchange with the ocean varies seasonally, and alternating periods can arise where the nutrient most limiting to phytoplankton growth switches. Transitions between these alternating periods can be sudden or gradual and this depends on human activities, such as reservoir construction and interbasin water transfers. How such activities might influence phytoplankton assemblages is largely unknown. Here, we employed a multispecies, multi-nutrient model to explore how nutrient loading switching mode might affect characteristics of phytoplankton assemblages. The model is based on the Monod-relationship, predicting an instantaneous growth rate from ambient inorganic nutrient concentrations whereas the limiting nutrient at any given time was determined by Liebig’s Law of the Minimum. Our simulated phytoplankton assemblages self-organized from species rich pools over a 15-year period, and only the surviving species were considered as assemblage members. Using the model, we explored the interactive effects of complementarity level in trait trade-offs within phytoplankton assemblages and the amount of noise in the resource supply concentrations. We found that the effect of shift from a sudden resource supply transition to a gradual one, as observed in systems impacted by watershed development, was dependent on the level of complementarity. In the extremes, phytoplankton species richness and relative overyielding increased when complementarity was lowest, and phytoplankton biomass increased greatly when complementarity was highest. For low-complementarity simulations, the persistence of poorer-performing phytoplankton species of intermediate R*s led to higher richness and relative overyielding. For high-complementarity simulations, the formation of phytoplankton species clusters and niche compression enabled higher biomass accumulation. Our findings suggest that an understanding of factors influencing the emergence of life history traits important to complementarity is necessary to predict the impact of watershed development on phytoplankton productivity and assemblage structure. PMID:25799563

Nutrient uplift in a cyclonic eddy increases diversity, primary productivity and iron demand of microbial communities relative to a western boundary current

PubMed Central

Petrou, Katherina; Sinutok, Sutinee; Seymour, Justin R.; Messer, Lauren F.; Brown, Mark V.; Norman, Louiza; Everett, Jason D.; McInnes, Allison S.; Ralph, Peter J.; Thompson, Peter A.; Hassler, Christel S.

2016-01-01

The intensification of western boundary currents in the global ocean will potentially influence meso-scale eddy generation, and redistribute microbes and their associated ecological and biogeochemical functions. To understand eddy-induced changes in microbial community composition as well as how they control growth, we targeted the East Australian Current (EAC) region to sample microbes in a cyclonic (cold-core) eddy (CCE) and the adjacent EAC. Phototrophic and diazotrophic microbes were more diverse (2–10 times greater Shannon index) in the CCE relative to the EAC, and the cell size distribution in the CCE was dominated (67%) by larger micro-plankton \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$(\\geq 20\\lrm{\\mu }\\mathrm{m})$\\end{document}≥20μm, as opposed to pico- and nano-sized cells in the EAC. Nutrient addition experiments determined that nitrogen was the principal nutrient limiting growth in the EAC, while iron was a secondary limiting nutrient in the CCE. Among the diazotrophic community, heterotrophic NifH gene sequences dominated in the EAC and were attributable to members of the gamma-, beta-, and delta-proteobacteria, while the CCE contained both phototrophic and heterotrophic diazotrophs, including Trichodesmium, UCYN-A and gamma-proteobacteria. Daily sampling of incubation bottles following nutrient amendment captured a cascade of effects at the cellular, population and community level, indicating taxon-specific differences in the speed of response of microbes to nutrient supply. Nitrogen addition to the CCE community increased picoeukaryote chlorophyll a quotas within 24 h, suggesting that nutrient uplift by eddies causes a ‘greening’ effect as well as an increase in phytoplankton biomass. After three days in both the EAC and CCE, diatoms increased in abundance with macronutrient (N, P, Si) and iron amendment, whereas haptophytes and phototrophic dinoflagellates declined. Our results indicate that cyclonic eddies increase delivery of nitrogen to the upper ocean to potentially mitigate the negative consequences of increased stratification due to ocean warming, but also increase the biological demand for iron that is necessary to sustain the growth of large-celled phototrophs and potentially support the diversity of diazotrophs over longer time-scales. PMID:27168982

EPS forces in Bacillus subtilis biofilms

NASA Astrophysics Data System (ADS)

Zhang, Wenbo; Angelini, Thomas; Tsai, Shih-Ming; Nixon, Ryan

2014-03-01

Bacteria have evolved to congregate in complex communities known as biofilms. The structure that holds a biofilm together is a matrix called extracellular polymeric substance (EPS). It has been observed in previous studies that EPS up-regulation occurs when the nutrient levels fall below a threshold concentration; this increase in EPS concentration produces an osmotic pressure that forces the colony to spread outward. This osmotic pressure may drive nutrient uptake, but the stresses generated by the EPS matrix has never been measured. Here we present measurements of the forces exerted by a biofilm on its supporting substrate and on its fluid nutrients. In our experiments, we use a technique analogous to traction force microscopy to measure strain in agar nutrient substrates imposed by Bacillus subtilis biofilms. By running additional test to measure the permeability and elastic modulus of the agar, we can estimate the pressure generated by the biofilm.

Nutrient enrichment and precipitation changes do not enhance resiliency of salt marshes to sea level rise in the Northeastern U.S.

EPA Science Inventory

In the U.S. Northeast, salt marshes are exceptionally vulnerable to the effects of accelerated sea level rise as compensatory mechanisms relying on positive feedbacks between inundation and sediment deposition are insufficient to counter inundation increases in low turbidity tida...

Effects of their nutrient precursors on the synthesis and release of serotonin, the catecholamines, and acetylcholine - Implications for behavioral disorders

NASA Technical Reports Server (NTRS)

Wurtman, Richard J.

1988-01-01

Authentic foods affect brain serotonin synthesis by modifying brain tryptophan levels, carbohydrates increasing and proteins decreasing these levels. The carbohydrate-induced rise in brain serotonin tends to diminish the likelihood that one carbohydrate-rich, protein-poor meal or snack will be followed by another. This mechanism is apparently disturbed in carbohydrate-craving obesity, which may explain why this syndrome responds well to d-fenfluramine, a serotoninergic drug. Pure nutrients like tyrosine or choline can also affect the rates at which their neurotransmitter products, the catecholamines and acetylcholine, are synthesized in and released from nerve terminals, suggesting that these compounds may find uses as drugs.

Light, nutrients, and food-chain length constrain planktonic energy transfer efficiency across multiple trophic levels

PubMed Central

Dickman, Elizabeth M.; Newell, Jennifer M.; González, María J.; Vanni, Michael J.

2008-01-01

The efficiency of energy transfer through food chains [food chain efficiency (FCE)] is an important ecosystem function. It has been hypothesized that FCE across multiple trophic levels is constrained by the efficiency at which herbivores use plant energy, which depends on plant nutritional quality. Furthermore, the number of trophic levels may also constrain FCE, because herbivores are less efficient in using plant production when they are constrained by carnivores. These hypotheses have not been tested experimentally in food chains with 3 or more trophic levels. In a field experiment manipulating light, nutrients, and food-chain length, we show that FCE is constrained by algal food quality and food-chain length. FCE across 3 trophic levels (phytoplankton to carnivorous fish) was highest under low light and high nutrients, where algal quality was best as indicated by taxonomic composition and nutrient stoichiometry. In 3-level systems, FCE was constrained by the efficiency at which both herbivores and carnivores converted food into production; a strong nutrient effect on carnivore efficiency suggests a carryover effect of algal quality across 3 trophic levels. Energy transfer efficiency from algae to herbivores was also higher in 2-level systems (without carnivores) than in 3-level systems. Our results support the hypothesis that FCE is strongly constrained by light, nutrients, and food-chain length and suggest that carryover effects across multiple trophic levels are important. Because many environmental perturbations affect light, nutrients, and food-chain length, and many ecological services are mediated by FCE, it will be important to apply these findings to various ecosystem types. PMID:19011082

Comparison of Nutrient Drivers and Response Metrics in Oregon Estuaries

EPA Science Inventory

With the goal of assessing sensitivity to nutrient enrichment, we present a cross-estuary comparison of nutrient sources, levels, and biological responses (phytoplankton and macroalgae) for thirteen Oregon estuaries. Nitrogen levels in the upstream portions of the estuaries are ...

Scaling up food production in the Upper Mississippi river basin: modeling impacts on water quality and nutrient cycling

NASA Astrophysics Data System (ADS)

Bowen, E. E.; Martin, P. A.; Schuble, T. J.; Yan, E.; Demissie, Y.

2010-12-01

Agricultural production imposes significant environmental stress on the landscape, both in the intensity and extent of agricultural activities. Among the most significant impacts, agriculture dominates the natural reactive nitrogen cycle, with excess reactive nitrogen leading to the degraded quality of inland and coastal waters. In the U.S., policymakers and stakeholders nationwide continue to debate strategies for decreasing environmental degradation from agricultural lands. Such strategies aim to optimize the balance among competing demands for food, fuel and ecosystem services. One such strategy increasingly discussed in the national debate is that of localizing food production around urban areas, developing what some have recently called “foodsheds”. However, the environmental impacts of localizing food production around population centers are not well-understood given the hard-to-generalize variety seen in management practices currently employed among local farms marketing food crops directly to consumers. As a first, landscape level study of potential impacts from scaling up this type of agriculture, we use the USDA Soil and Water Assessment Tool (SWAT) model to quantify environmental impacts from developing foodsheds for all population centers in the Upper Mississippi river basin. Specifically, we focus on nutrient cycling and water quality impacts determining direct greenhouse gas emissions and changes to nutrient runoff from increased food production in this watershed. We investigate a variety of scenarios in which food production is scaled up to the regional level using different types of farm management practices, ranging from conventional production of fruits and vegetables, to production of these products from small-scale, diversified systems integrating conservation easements. In addition to impacts on nutrient cycling and water quality, we also characterize relative levels of productivity in conjunction with overall demand for food associated with population centers to address one aspect of socio-economic concern.

Salmon-derived nitrogen in terrestrial invertebrates from coniferous forests of the Pacific Northwest

PubMed Central

2002-01-01

Background Bi-directional flow of nutrients between marine and terrestrial ecosystems can provide essential resources that structure communities in transitional habitats. On the Pacific coast of North America, anadromous salmon (Oncorhynchus spp.) constitute a dominant nutrient subsidy to aquatic habitats and riparian vegetation, although the contribution to terrestrial habitats is not well established. We use a dual isotope approach of δ15N and δ13C to test for the contribution of salmon nutrients to multiple trophic levels of litter-based terrestrial invertebrates below and above waterfalls that act as a barrier to salmon migration on two watersheds in coastal British Columbia. Results Invertebrates varied predictably in δ15N with enrichment of 3–8‰ below the falls compared with above the falls in all trophic groups on both watersheds. We observed increasing δ15N levels in our invertebrate groups with increasing consumption of dietary protein. Invertebrates varied in δ13C but did not always vary predictably with trophic level or habitat. From 19.4 to 71.5% of invertebrate total nitrogen was originally derived from salmon depending on taxa, watershed, and degree of fractionation from the source. Conclusions Enrichment of δ15N in the invertebrate community below the falls in conjunction with the absence of δ13C enrichment suggests that enrichment in δ15N occurs primarily through salmon-derived nitrogen subsidies to litter, soil and vegetation N pools rather than from direct consumption of salmon tissue or salmon tissue consumers. Salmon nutrient subsidies to terrestrial habitats may result in shifts in invertebrate community structure, with subsequent implications for higher vertebrate consumers, particularly the passerines. PMID:11914157

Seed dimorphism, nutrients and salinity differentially affect seed traits of the desert halophyte Suaeda aralocaspica via multiple maternal effects.

PubMed

Wang, Lei; Baskin, Jerry M; Baskin, Carol C; Cornelissen, J Hans C; Dong, Ming; Huang, Zhenying

2012-09-25

Maternal effects may influence a range of seed traits simultaneously and are likely to be context-dependent. Disentangling the interactions of plant phenotype and growth environment on various seed traits is important for understanding regeneration and establishment of species in natural environments. Here, we used the seed-dimorphic plant Suaeda aralocaspica to test the hypothesis that seed traits are regulated by multiple maternal effects. Plants grown from brown seeds had a higher brown:black seed ratio than plants from black seeds, and germination percentage of brown seeds was higher than that of black seeds under all conditions tested. However, the coefficient of variation (CV) for size of black seeds was higher than that of brown seeds. Seeds had the smallest CV at low nutrient and high salinity for plants from brown seeds and at low nutrient and low salinity for plants from black seeds. Low levels of nutrients increased size and germinability of black seeds but did not change the seed morph ratio or size and germinability of brown seeds. High levels of salinity decreased seed size but did not change the seed morph ratio. Seeds from high-salinity maternal plants had a higher germination percentage regardless of level of germination salinity. Our study supports the multiple maternal effects hypothesis. Seed dimorphism, nutrient and salinity interacted in determining a range of seed traits of S. aralocaspica via bet-hedging and anticipatory maternal effects. This study highlights the importance of examining different maternal factors and various offspring traits in studies that estimate maternal effects on regeneration.

Seed dimorphism, nutrients and salinity differentially affect seed traits of the desert halophyte Suaeda aralocaspica via multiple maternal effects

PubMed Central

2012-01-01

Background Maternal effects may influence a range of seed traits simultaneously and are likely to be context-dependent. Disentangling the interactions of plant phenotype and growth environment on various seed traits is important for understanding regeneration and establishment of species in natural environments. Here, we used the seed-dimorphic plant Suaeda aralocaspica to test the hypothesis that seed traits are regulated by multiple maternal effects. Results Plants grown from brown seeds had a higher brown:black seed ratio than plants from black seeds, and germination percentage of brown seeds was higher than that of black seeds under all conditions tested. However, the coefficient of variation (CV) for size of black seeds was higher than that of brown seeds. Seeds had the smallest CV at low nutrient and high salinity for plants from brown seeds and at low nutrient and low salinity for plants from black seeds. Low levels of nutrients increased size and germinability of black seeds but did not change the seed morph ratio or size and germinability of brown seeds. High levels of salinity decreased seed size but did not change the seed morph ratio. Seeds from high-salinity maternal plants had a higher germination percentage regardless of level of germination salinity. Conclusions Our study supports the multiple maternal effects hypothesis. Seed dimorphism, nutrient and salinity interacted in determining a range of seed traits of S. aralocaspica via bet-hedging and anticipatory maternal effects. This study highlights the importance of examining different maternal factors and various offspring traits in studies that estimate maternal effects on regeneration. PMID:23006315

Community-based wastewater treatment systems and water quality of an Indonesian village.

PubMed

Lim, H S; Lee, L Y; Bramono, S E

2014-03-01

This paper examines the impact of community-based water treatment systems on water quality in a peri-urban village in Yogyakarta, Indonesia. Water samples were taken from the wastewater treatment plants (WWTPs), irrigation canals, paddy fields and wells during the dry and wet seasons. The samples were tested for biological and chemical oxygen demand, nutrients (ammonia, nitrate, total nitrogen and total phosphorus) and Escherichia coli. Water quality in this village is affected by the presence of active septic tanks, WWTP effluent discharge, small-scale tempe industries and external sources. We found that the WWTPs remove oxygen-demanding wastes effectively but discharged nutrients, such as nitrate and ammonia, into irrigation canals. Irrigation canals had high levels of E. coli as well as oxygen-demanding wastes. Well samples had high E. coli, nitrate and total nitrogen levels. Rainfall tended to increase concentrations of biological and chemical oxygen demand and some nutrients. All our samples fell within the drinking water standards for nitrate but failed the international and Indonesian standards for E. coli. Water quality in this village can be improved by improving the WWTP treatment of nutrients, encouraging more villagers to be connected to WWTPs and controlling hotspot contamination areas in the village.

Calcification and photosynthesis of the coral acropora cervicornis under calcium limited conditions

NASA Technical Reports Server (NTRS)

Rathfon, Megan; Brewer, Debbie

1997-01-01

Differing hypothesis about the function of calcification are based on an interesting dilemma. Is the purpose of calcification mainly a structural and protective one or does calcification serve other functions? Does photosynthesis increase carbonate ion activity and cause calcification or does calcification increase CO2 levels and stimulate photsynthesis? It is proposed that calcification in corals is not dependent upon photosynthesis but upon calcium levels in the water. Under normal ocean conditions, corals convert a certain percentage of energy to photosynthesis and respiration and another percentage to calcification. As corals become nutrient stressed, particularly calcium limited, the ratio of photosynthesis to calcification shifts towards calcification in order to generate protons. The protons generated during calcification may stimulate photosynthesis and aid in the uptake of nutrients and biocarbonates. The results of the calcification experiment show a trend towards increased calcification and decreased photosynthesis when the coral Acropora cervicornis is calcium limited, but the data are inconclusive and further research is needed.

Replacement of fish meal protein by surimi by-product protein in the diet of blue gourami Trichogaster trichopterus fingerlings.

PubMed

Mohanta, K N; Subramanian, S; Korikanthimath, V S

2013-02-01

Based on the nutrient requirement of Trichogaster trichopterus, a fish meal-based basal diet with 350 g/kg diet crude protein and 16.7 MJ/kg energy was formulated, in which the fish meal protein was replaced by surimi by-product protein at 0.0 (control), 12.5, 25, 50, 75 and 100% levels. The formulated diets were fed ad libitum to T. trichopterus fingerlings (4.80 ± 0.03 g) in triplicate groups for 45 days in a closed water system. Eighteen fibre-reinforced plastic tanks with 200 l of water were used for rearing the fish. Weight gain, specific growth rate, feed/gain ratio, protein efficiency ratio, nutrient retention and digestibility (protein and energy) of fish were not affected (p > 0.05) up to 50% fish meal protein replacement level by surimi by-product protein. While whole-body protein content of fish was marginally decreased, the lipid content was increased with increase in surumi by-product incorporation level in the diet. The study results suggest that the fish meal protein, which is scarce and costly nowadays, could be replaced up to 50% by surimi by-product protein in the diet of blue gourami without hampering the growth and nutrient utilization of fish. © 2011 Blackwell Verlag GmbH.

Growth and Lead Accumulation Capacity of Lemna minor and Spirodela polyrhiza (Lemnaceae): Interactions with Nutrient Enrichment

PubMed Central

Aksoy, Ahmet

2010-01-01

A study to understand the biological effects of samples prepared with lead and the effects of lead were conducted on Lemna minor L. and Spirodela polyrhiza (L.) Schleid. This study was intended to test the hypothesis that nutrient enrichment (P, NO3−–N and SO42−) enhances the metal tolerance of floating macrophytes. The plants were exposed to Pb concentrations 0, 1, 5, 10, 25, and 50 mg l−1 for a period of 1, 3, 5, and 7 days. L. minor accumulated 561 mg g−1 dry weight (dw) Pb, and S. polyrhiza accumulated 330 mg g−1 dw Pb after 7 days, whereas in the groups enriched with nutrients, L. minor accumulated 128.7 mg g−1 Pb and S. polyrhiza accumulated 68.7 mg g−1 dw Pb after 7 days. Relative growth rates and photosynthetic pigments (chlorophyll a, b, and carotenoid) were measured in L. minor and S. polyrhiza exposed to different Pb concentrations under laboratory conditions. Relative growth rates were negatively correlated with metal exposure, but nutrient addition was found to suppress this effect. Photosynthetic pigment levels were found negatively correlated with metal exposure, and nutrient addition attenuated chlorophyll decrease in response to metal exposure. Metal and nutrient concentration in water decreased throughout the experiments. The study concluded that nutrient enrichment increases the tolerance of L. minor and S. polyrhiza to metals, that L. minor and S. polyrhiza are suitable candidates for the phytoremediation of low-level lead pollution, and that L. minor was more effective in extracting lead than was S. polyrhiza. PMID:21258435

Impacts of elevated terrestrial nutrient loads and temperature on pelagic food-web efficiency and fish production.

PubMed

Lefébure, R; Degerman, R; Andersson, A; Larsson, S; Eriksson, L-O; Båmstedt, U; Byström, P

2013-05-01

Both temperature and terrestrial organic matter have strong impacts on aquatic food-web dynamics and production. Temperature affects vital rates of all organisms, and terrestrial organic matter can act both as an energy source for lower trophic levels, while simultaneously reducing light availability for autotrophic production. As climate change predictions for the Baltic Sea and elsewhere suggest increases in both terrestrial matter runoff and increases in temperature, we studied the effects on pelagic food-web dynamics and food-web efficiency in a plausible future scenario with respect to these abiotic variables in a large-scale mesocosm experiment. Total basal (phytoplankton plus bacterial) production was slightly reduced when only increasing temperatures, but was otherwise similar across all other treatments. Separate increases in nutrient loads and temperature decreased the ratio of autotrophic:heterotrophic production, but the combined treatment of elevated temperature and terrestrial nutrient loads increased both fish production and food-web efficiency. CDOM: Chl a ratios strongly indicated that terrestrial and not autotrophic carbon was the main energy source in these food webs and our results also showed that zooplankton biomass was positively correlated with increased bacterial production. Concomitantly, biomass of the dominant calanoid copepod Acartia sp. increased as an effect of increased temperature. As the combined effects of increased temperature and terrestrial organic nutrient loads were required to increase zooplankton abundance and fish production, conclusions about effects of climate change on food-web dynamics and fish production must be based on realistic combinations of several abiotic factors. Moreover, our results question established notions on the net inefficiency of heterotrophic carbon transfer to the top of the food web. © 2013 Blackwell Publishing Ltd.

Diatom Cell Size, Coloniality and Motility: Trade-Offs between Temperature, Salinity and Nutrient Supply with Climate Change

PubMed Central

Svensson, Filip; Norberg, Jon; Snoeijs, Pauline

2014-01-01

Reduction in body size has been proposed as a universal response of organisms, both to warming and to decreased salinity. However, it is still controversial if size reduction is caused by temperature or salinity on their own, or if other factors interfere as well. We used natural benthic diatom communities to explore how “body size” (cells and colonies) and motility change along temperature (2–26°C) and salinity (0.5–7.8) gradients in the brackish Baltic Sea. Fourth-corner analysis confirmed that small cell and colony sizes were associated with high temperature in summer. Average community cell volume decreased linearly with 2.2% per °C. However, cells were larger with artificial warming when nutrient concentrations were high in the cold season. Average community cell volume increased by 5.2% per °C of artificial warming from 0 to 8.5°C and simultaneously there was a selection for motility, which probably helped to optimize growth rates by trade-offs between nutrient supply and irradiation. Along the Baltic Sea salinity gradient cell size decreased with decreasing salinity, apparently mediated by nutrient stoichiometry. Altogether, our results suggest that climate change in this century may polarize seasonality by creating two new niches, with elevated temperature at high nutrient concentrations in the cold season (increasing cell size) and elevated temperature at low nutrient concentrations in the warm season (decreasing cell size). Higher temperature in summer and lower salinity by increased land-runoff are expected to decrease the average cell size of primary producers, which is likely to affect the transfer of energy to higher trophic levels. PMID:25279720

Diatom cell size, coloniality and motility: trade-offs between temperature, salinity and nutrient supply with climate change.

PubMed

Svensson, Filip; Norberg, Jon; Snoeijs, Pauline

2014-01-01

Reduction in body size has been proposed as a universal response of organisms, both to warming and to decreased salinity. However, it is still controversial if size reduction is caused by temperature or salinity on their own, or if other factors interfere as well. We used natural benthic diatom communities to explore how "body size" (cells and colonies) and motility change along temperature (2-26°C) and salinity (0.5-7.8) gradients in the brackish Baltic Sea. Fourth-corner analysis confirmed that small cell and colony sizes were associated with high temperature in summer. Average community cell volume decreased linearly with 2.2% per °C. However, cells were larger with artificial warming when nutrient concentrations were high in the cold season. Average community cell volume increased by 5.2% per °C of artificial warming from 0 to 8.5°C and simultaneously there was a selection for motility, which probably helped to optimize growth rates by trade-offs between nutrient supply and irradiation. Along the Baltic Sea salinity gradient cell size decreased with decreasing salinity, apparently mediated by nutrient stoichiometry. Altogether, our results suggest that climate change in this century may polarize seasonality by creating two new niches, with elevated temperature at high nutrient concentrations in the cold season (increasing cell size) and elevated temperature at low nutrient concentrations in the warm season (decreasing cell size). Higher temperature in summer and lower salinity by increased land-runoff are expected to decrease the average cell size of primary producers, which is likely to affect the transfer of energy to higher trophic levels.

In vitro growth of Curcuma longa L. in response to five mineral elements and plant density in fed-batch culture systems.

PubMed

El-Hawaz, Rabia F; Bridges, William C; Adelberg, Jeffrey W

2015-01-01

Plant density was varied with P, Ca, Mg, and KNO3 in a multifactor experiment to improve Curcuma longa L. micropropagation, biomass and microrhizome development in fed-batch liquid culture. The experiment had two paired D-optimal designs, testing sucrose fed-batch and nutrient sucrose fed-batch techniques. When sucrose became depleted, volume was restored to 5% m/v sucrose in 200 ml of modified liquid MS medium by adding sucrose solutions. Similarly, nutrient sucrose fed-batch was restored to set points with double concentration of treatments' macronutrient and MS micronutrient solutions, along with sucrose solutions. Changes in the amounts of water and sucrose supplementations were driven by the interaction of P and KNO3 concentrations. Increasing P from 1.25 to 6.25 mM increased both multiplication and biomass. The multiplication ratio was greatest in the nutrient sucrose fed-batch technique with the highest level of P, 6 buds/vessel, and the lowest level of Ca and KNO3. The highest density (18 buds/vessel) produced the highest fresh biomass at the highest concentrations of KNO3 and P with nutrient sucrose fed-batch, and moderate Ca and Mg concentrations. However, maximal rhizome dry biomass required highest P, sucrose fed-batch, and a moderate plant density. Different media formulations and fed-batch techniques were identified to maximize the propagation and storage organ responses. A single experimental design was used to optimize these dual purposes.

In Vitro Growth of Curcuma longa L. in Response to Five Mineral Elements and Plant Density in Fed-Batch Culture Systems

PubMed Central

El-Hawaz, Rabia F.; Bridges, William C.; Adelberg, Jeffrey W.

2015-01-01

Plant density was varied with P, Ca, Mg, and KNO3 in a multifactor experiment to improve Curcuma longa L. micropropagation, biomass and microrhizome development in fed-batch liquid culture. The experiment had two paired D-optimal designs, testing sucrose fed-batch and nutrient sucrose fed-batch techniques. When sucrose became depleted, volume was restored to 5% m/v sucrose in 200 ml of modified liquid MS medium by adding sucrose solutions. Similarly, nutrient sucrose fed-batch was restored to set points with double concentration of treatments’ macronutrient and MS micronutrient solutions, along with sucrose solutions. Changes in the amounts of water and sucrose supplementations were driven by the interaction of P and KNO3 concentrations. Increasing P from 1.25 to 6.25 mM increased both multiplication and biomass. The multiplication ratio was greatest in the nutrient sucrose fed-batch technique with the highest level of P, 6 buds/vessel, and the lowest level of Ca and KNO3. The highest density (18 buds/vessel) produced the highest fresh biomass at the highest concentrations of KNO3 and P with nutrient sucrose fed-batch, and moderate Ca and Mg concentrations. However, maximal rhizome dry biomass required highest P, sucrose fed-batch, and a moderate plant density. Different media formulations and fed-batch techniques were identified to maximize the propagation and storage organ responses. A single experimental design was used to optimize these dual purposes. PMID:25830292

Insights for Setting of Nutrient Requirements, Gleaned by Comparison of Selenium Status Biomarkers in Turkeys and Chickens versus Rats, Mice, and Lambs12

PubMed Central

Sunde, Roger A; Li, Jin-Long; Taylor, Rachel M

2016-01-01

To gain insights into nutrient biomarkers and setting of dietary nutrient requirements, selenium biomarker levels and requirements in response to multiple graded levels of dietary selenium were compared between day-old turkeys and chickens versus weanling rats and mice and 2-d-old lambs supplemented with sodium selenite. In rodents, there was no significant effect of dietary selenium on growth, indicating that the minimum selenium requirement was <0.007 μg Se/g diet. In contrast, there was a significant effect in turkeys, chicks, and lambs, which showed selenium requirements for growth of 0.05, 0.025, and 0.05 μg Se/g diet, respectively. Liver glutathione peroxidase (GPX) 1 activity fell in all species to <4% of selenium-adequate levels, plasma GPX3 activity fell to <3% in all species except for mice, and liver GPX4 activity fell to <10% in avians but only to ∼50% of selenium-adequate levels in rodents. Selenium-response curves for these biomarkers reached well-defined plateaus with increasing selenium supplementation in all species, collectively indicating minimum selenium requirements of 0.06–0.10 μg Se/g for rats, mice, and lambs but 0.10–0.13 μg Se/g for chicks and 0.23–0.33 μg Se/g for turkeys. In contrast, increasing dietary selenium did not result in well-defined plateaus for erythrocyte GPX1 activity and liver selenium in most species. Selenium-response curves for GPX1 mRNA for rodents and avians had well-defined plateaus and similar breakpoints. GPX4 mRNA was not significantly regulated by dietary selenium in rodents, but GPX4 mRNA in avians decreased in selenium deficiency to ∼35% of selenium-adequate plateau levels. Notably, no selenoprotein activities or mRNA were effective biomarkers for supernutritional selenium status. Robust biomarkers, such as liver GPX1 and plasma GPX3 activity for selenium, should be specific for the nutrient, fall dramatically in deficiency, and reach well-defined plateaus. Differences in biomarker-response curves may help researchers better understand nutrient metabolism and targeting of tissues in deficiency, thus to better characterize requirements. PMID:28140330

Insights for Setting of Nutrient Requirements, Gleaned by Comparison of Selenium Status Biomarkers in Turkeys and Chickens versus Rats, Mice, and Lambs.

PubMed

Sunde, Roger A; Li, Jin-Long; Taylor, Rachel M

2016-11-01

To gain insights into nutrient biomarkers and setting of dietary nutrient requirements, selenium biomarker levels and requirements in response to multiple graded levels of dietary selenium were compared between day-old turkeys and chickens versus weanling rats and mice and 2-d-old lambs supplemented with sodium selenite. In rodents, there was no significant effect of dietary selenium on growth, indicating that the minimum selenium requirement was <0.007 μg Se/g diet. In contrast, there was a significant effect in turkeys, chicks, and lambs, which showed selenium requirements for growth of 0.05, 0.025, and 0.05 μg Se/g diet, respectively. Liver glutathione peroxidase (GPX) 1 activity fell in all species to <4% of selenium-adequate levels, plasma GPX3 activity fell to <3% in all species except for mice, and liver GPX4 activity fell to <10% in avians but only to ∼50% of selenium-adequate levels in rodents. Selenium-response curves for these biomarkers reached well-defined plateaus with increasing selenium supplementation in all species, collectively indicating minimum selenium requirements of 0.06-0.10 μg Se/g for rats, mice, and lambs but 0.10-0.13 μg Se/g for chicks and 0.23-0.33 μg Se/g for turkeys. In contrast, increasing dietary selenium did not result in well-defined plateaus for erythrocyte GPX1 activity and liver selenium in most species. Selenium-response curves for GPX1 mRNA for rodents and avians had well-defined plateaus and similar breakpoints. GPX4 mRNA was not significantly regulated by dietary selenium in rodents, but GPX4 mRNA in avians decreased in selenium deficiency to ∼35% of selenium-adequate plateau levels. Notably, no selenoprotein activities or mRNA were effective biomarkers for supernutritional selenium status. Robust biomarkers, such as liver GPX1 and plasma GPX3 activity for selenium, should be specific for the nutrient, fall dramatically in deficiency, and reach well-defined plateaus. Differences in biomarker-response curves may help researchers better understand nutrient metabolism and targeting of tissues in deficiency, thus to better characterize requirements. © 2016 American Society for Nutrition.

Regional classification of Pacific Northwest estuaries by wetland and land cover patterns

USGS Publications Warehouse

Lee,; Brown, A; Clinton, J; Hagerty,

2009-01-01

harmful algal blooms, and detrimental increases in benthic macroalgae. The nature and severity of the impacts vary with the level of nutrient loading as well as with the estuary type and regional drivers.

Recent insights into physiological responses to nutrients by the cylindrospermopsin producing cyanobacterium, Cylindrospermopsis raciborskii

NASA Astrophysics Data System (ADS)

Burford, Michele A.; Willis, Anusuya; Chuang, Ann; Man, Xiao; Orr, Phil

2017-11-01

The harmful cyanobacterium Cylindrospermopsis raciborskii is a widespread species increasingly being recorded in freshwater systems around the world. Studies have demonstrated some key attributes of this species which may explain its global dominance. It has a high level of flexibility with respect to light and nutrients, being capable of growth under low and variable light conditions. However, it is the strategy with respect to nutrient utilization that has received more attention. Unlike many bloom forming species, the dominance of this species is not simply linked to higher nutrient loads. In fact it appears that it is more competitive when phosphorus and nitrogen availability is low and/or variable. An important component of this flexibility appears to be the result of within-population strain variability in responses to nutrients, as well as key physiological adaptations. Strain variability also appears to have an effect on the population-level cell quota of toxins, specifically cylindrospermopsins (CYNs). Field studies in Australia showed that populations had the highest proportion of toxic strains when dissolved inorganic phosphorus was added, resulting in stoichiometrically balanced nitrogen and phosphorus within the cells. These strategies are part of an arsenal of responses to environmental conditions, making it a challenging species to manage. However, our ability to improve bloom prediction will rely on a more detailed understanding of the complex physiology and ecology of this species.

Effects of Erosion from Mounds of Different Termite Genera on Distinct Functional Grassland Types in an African Savannah.

PubMed

Gosling, Cleo M; Cromsigt, Joris P G M; Mpanza, Nokukhanya; Olff, Han

A key aspect of savannah vegetation heterogeneity is mosaics formed by two functional grassland types, bunch grasslands, and grazing lawns. We investigated the role of termites, important ecosystem engineers, in creating high-nutrient patches in the form of grazing lawns. Some of the ways termites can contribute to grazing lawn development is through erosion of soil from aboveground mounds to the surrounding soil surface. This may alter the nutrient status of the surrounding soils. We hypothesize that the importance of this erosion varies with termite genera, depending on feeding strategy and mound type. To test this, we simulated erosion by applying mound soil from three termite genera ( Macrotermes , Odontotermes , and Trinervitermes ) in both a field experiment and a greenhouse experiment. In the greenhouse experiment, we found soils with the highest macro nutrient levels (formed by Trinervitermes ) promoted the quality and biomass of both a lawn ( Digitaria longiflora ) and a bunch ( Sporobolus pyramidalis ) grass species. In the field we found that soils with the highest micro nutrient levels (formed by Macrotermes ) showed the largest increase in cover of grazing lawn species. By linking the different nutrient availability of the mounds to the development of different grassland states, we conclude that the presence of termite mounds influences grassland mosaics, but that the type of mound plays a crucial role in determining the nature of the effects.

Characterization of the Kootenai River Aquatic Macroinvertebrate Community before and after Experimental Nutrient Addition, 2003-2006. [Chapter 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holderman, Charlie

2009-02-19

The Kootenai River ecosystem has experienced numerous ecological changes since the early 1900s. Some of the largest impacts to habitat, biological communities, and ecological function resulted from levee construction along the 120 km of river upstream from Kootenay Lake, completed by the 1950s, and the construction and operation of Libby Dam, completed in 1972 on the river near Libby Montana. Levee construction isolated tens of thousands of hectares of historic functioning floodplain habitat from the river channel, eliminating nutrient production and habitat diversity crucial to the functioning of a large river-floodplain ecosystem. Libby Dam continues to create large changes inmore » the timing, duration, and magnitude of river flows, and greatly reduces sediment and nutrient transport to downstream river reaches. These changes have contributed to the ecological collapse of the post-development Kootenai River ecosystem and its native biological communities. In response to this artificial loss of nutrients, experimental nutrient addition was initiated in the Kootenay Lake's North Arm in 1992, the South Arm in 2004, and in the Kootenai River at the Idaho-Montana border during 2005. This report characterizes the macroinvertebrate community in the Kootenai River and its response to experimental nutrient addition during 2005 and 2006. This report also provides an initial evaluation of cascading trophic interactions in response to nutrient addition. Macroinvertebrates were sampled at 12 sites along a 325 km section of the Kootenai River, representing an upriver unimpounded reference reach, treatment and control canyon reach sites, and braided and meandering reach sites, all downstream from Libby Dam. Principle component analysis revealed that richness explained the greatest amount of variability in response to nutrient addition as did taxa from Acari, Coleoptera, Ephemeroptera, Plecoptera, and Trichoptera. Analysis of variance revealed that nutrient addition had a significant effect (p<0.0001) on invertebrate abundance, biomass, and richness at sites KR-9 and KR-9.1 combined (the zone of maximum biological response). Richness, a valuable ecological metric, increased more than abundance and biomass, which were subject to greater sampling bias. Cascading trophic interactions were observed as increased algal accrual, increased in-river invertebrate abundance, and increased invertebrate counts in mountain whitefish (Prosopium williamsonii) guts samples, but were not quantitatively tested. Sampling and analyses across trophic levels are currently ongoing and are expected to better characterize ecological responses to experimental nutrient addition in the Kootenai River.« less

Productivity, fertilizer responses and nutrient balances of farming systems in central Tigray, Ethiopia: a multi-perspective view in relation to degradation.

NASA Astrophysics Data System (ADS)

Kraaijvanger, Richard; Veldkamp, Tom; Nyssen, Jan

2014-05-01

In many rural livelihoods in sub-Saharan Africa, crop productivity plays an important role since it links with food insecurity, which again is a major constraining factor in livelihood development. Sustainable livelihood development and land degradation are closely connected: lacking sustainability often results in land degradation, whereas the incidence of land degradation frequently frustrates sustainable development. Important forms of land degradation are soil erosion and nutrient depletion, both often being attributed to exhaustive land use practices and both having a direct and major impact on crop productivity. Application of nutrients is an important way to increase productivity. In our study area, central Tigray, development agents recommend the application of fertilizers at high rates in order to boost productivity and to deal with nutrient depletion. In the discussion about the use of fertilizers different perspectives can be taken, in which especially responses and nutrient balances are important issues, linking respectively with socio-economic and agro-ecological livelihood aspects. Ethiopian soils for example are, based on large scale nutrient balances, considered to be depleted, at field scale fertilizer responses are frequently disappointing and achieving sustainable nutrient balances at farm level seems difficult. At a temporal scale however, agricultural systems remained almost unchanged for over 2500 years, suggesting at least some degree of sustainability. With respect to productivity data resulting from on-farm experimentation with natural and artificial fertilizers in 26 sites, we took four perspectives, different in ownership and scale, on nutrient related land degradation and its assumed impact on crop productivity. Taking a farmer perspective we found no significant difference between responses to recommended and current farmer based practices. Taking a more scientific perspective highlighted that, based on the positive correlation between response and soil-P, phosphorus was limiting. A relatively short term farm-level perspective made clear that closing nutrient balances to achieve sustainability is difficult, only the use of manure seemed somewhat satisfactory in this. In case a long term perspective is taken, apparent historical sustainability seems to relate to the combination of relatively low yield levels and mixed farming. Depending on the perspective taken different interventions can be forwarded, all four perspectives however indicate that strengthening the existing mixed farming system provides a promising alternative, allowing the improvement of agro-ecological as well as socio-economic sustainability of involved livelihoods.

Biofortification in China: policy and practice

PubMed Central

Campos-Bowers, Monica H; Wittenmyer, Brian F

2007-01-01

Micronutrient deficiency undernutrition, due to insufficient levels of vitamins and minerals in the diet, remains one of the most prevalent and preventable nutritional problems in the world today. Micronutrient undernutrition is the most common form of malnutrition. Compared to the 180 million children with protein-energy malnutrition, 3.5–5 billion persons are iron-deficient, and 140–250 million persons are vitamin A-deficient. Micronutrient deficiencies diminish physical, cognitive, and reproductive development. Undernutrition is both a cause and a result of poor human health and achievement. Middle-income nations, such as China, also suffer from micronutrient undernutrition's effects. In China's poor western provinces, despite supplementation and fortification efforts, stunting and underweight (symptoms of micronutrient undernutrition) remain common. In recent decades, nutritional adequacy, in terms of available food energy, improved immensely, as the government made food security a top priority. A potential next step for China could be to address specifically micronutrient undernutrition. The paper aims to provide a discussion of policy issues relevant to biofortification, if China were to consider the implementation of this intervention in its rural provinces. Traditional nutritional interventions currently employ four main strategies: dietary modification, supplementation, commercial fortification, and biofortification. Biofortification, a relatively new technique, involves selectively breeding staple plant varieties to increase specific nutrient levels in plant tissues. Biofortification has the potential to provide benefits to humans, plants, and livestock; nourish nutrient-depleted soils; and help increase crop yields per acre. Biofortification methods include selective breeding, reducing levels of anti-nutrients, and increasing levels of substances that promote nutrient absorption. If China were to implement biofortification programs, with help from government agencies and international organizations, several policy questions would need to be addressed. The paper discusses several policy questions that pertain to the relationship between biofortified and genetically modified crops, human health and safety concerns, labeling of biofortified crops for consumers, consumer rights, potential environmental impacts, intellectual property rights, seed disbursement, government investment, private-sector research, and additional agricultural and commercial regulations. Biofortification has the potential to help alleviate the suffering, death, disability, and failure to achieve full human potential that results from micronutrient undernutrition-related diseases. PMID:17897456

Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients

PubMed Central

Golden, Christopher D.; Mozaffarian, Dariush

2016-01-01

Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model—the Global Expanded Nutrient Supply (GENuS) model—to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961–2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent estimates by the USDA for historical US nutrition and find very good agreement for 21 of 23 nutrients, though sodium and dietary fiber will require further improvement. PMID:26807571

Global Expanded Nutrient Supply (GENuS) Model: A New Method for Estimating the Global Dietary Supply of Nutrients.

PubMed

Smith, Matthew R; Micha, Renata; Golden, Christopher D; Mozaffarian, Dariush; Myers, Samuel S

2016-01-01

Insufficient data exist for accurate estimation of global nutrient supplies. Commonly used global datasets contain key weaknesses: 1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations. Here, we attempt to improve upon these datasets by constructing a new model--the Global Expanded Nutrient Supply (GENuS) model--to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries. Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011. We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, and then estimate the proportion of major cereals being processed to flours to increase to 225. Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed. Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet. To validate our new method, we compare the GENuS estimates of nutrient supplies against independent estimates by the USDA for historical US nutrition and find very good agreement for 21 of 23 nutrients, though sodium and dietary fiber will require further improvement.

Effects of shelter and enrichment on the ecology and nutrient cycling of microbial communities of subtidal carbonate sediments.

PubMed

Forehead, Hugh I; Kendrick, Gary A; Thompson, Peter A

2012-04-01

The interactions between physical disturbances and biogeochemical cycling are fundamental to ecology. The benthic microbial community controls the major pathway of nutrient recycling in most shallow-water ecosystems. This community is strongly influenced by physical forcing and nutrient inputs. Our study tests the hypotheses that benthic microbial communities respond to shelter and enrichment with (1) increased biomass, (2) change in community composition and (3) increased uptake of inorganic nutrients from the water column. Replicate in situ plots were sheltered from physical disturbance and enriched with inorganic nutrients or left without additional nutrients. At t(0) and after 10 days, sediment-water fluxes of nutrients, O(2) and N(2) , were measured, the community was characterized with biomarkers. Autochthonous benthic microalgal (BMA) biomass increased 30% with shelter and a natural fivefold increase in nutrient concentration; biomass did not increase with greater enrichment. Diatoms remained the dominant taxon of BMA, suggesting that the sediments were not N or Si limited. Bacteria and other heterotrophic organisms increased with enrichment and shelter. Daily exchanges of inorganic nutrients between sediments and the water column did not change in response to shelter or nutrient enrichment. In these sediments, physical disturbance, perhaps in conjunction with nutrient enrichment, was the primary determinant of microbial biomass. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Imaging and Analytical Approaches for Characterization of Soil Mineral Weathering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dohnalkova, Alice; Arey, Bruce; Varga, Tamas

Soil minerals weathering is the primary natural source of nutrients necessary to sustain productivity in terrestrial ecosystems. Soil microbial communities increase soil mineral weathering and mineral-derived nutrient availability through physical and chemical processes. Rhizosphere, the zone immediately surrounding plant roots, is a biogeochemical hotspot with microbial activity, soil organic matter production, mineral weathering, and secondary phase formation all happening in a small temporally ephemeral zone of steep geochemical gradients. The detailed exploration of the micro-scale rhizosphere is essential to our better understanding of large-scale processes in soils, such as nutrient cycling, transport and fate of soil components, microbial-mineral interactions, soilmore » erosion, soil organic matter turnover and its molecular-level characterization, and predictive modeling.« less

Lithium chloride protects retinal neurocytes from nutrient deprivation by promoting DNA non-homologous end-joining

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuang Jing; Li Fan; Liu Xuan

2009-03-13

Lithium chloride is a therapeutic agent for treatment of bipolar affective disorders. Increasing numbers of studies have indicated that lithium has neuroprotective effects. However, the molecular mechanisms underlying the actions of lithium have not been fully elucidated. This study aimed to investigate whether lithium chloride produces neuroprotective function by improving DNA repair pathway in retinal neurocyte. In vitro, the primary cultured retinal neurocytes (85.7% are MAP-2 positive cells) were treated with lithium chloride, then cultured with serum-free media to simulate the nutrient deprived state resulting from ischemic insult. The neurite outgrowth of the cultured cells increased significantly in a dose-dependentmore » manner when exposed to different levels of lithium chloride. Genomic DNA electrophoresis demonstrated greater DNA integrity of retinal neurocytes when treated with lithium chloride as compared to the control. Moreover, mRNA and protein levels of Ligase IV (involved in DNA non-homologous end-joining (NHEJ) pathway) in retinal neurocytes increased with lithium chloride. The end joining activity assay was performed to determine the role of lithium on NHEJ in the presence of extract from retinal neurocytes. The rejoining levels in retinal neurocytes treated with lithium were significantly increased as compared to the control. Furthermore, XRCC4, the Ligase IV partner, and the transcriptional factor, CREB and CTCF, were up-regulated in retinal cells after treating with 1.0 mM lithium chloride. Therefore, our data suggest that lithium chloride protects the retinal neural cells from nutrient deprivation in vitro, which may be similar to the mechanism of cell death in glaucoma. The improvement in DNA repair pathway involving in Ligase IV might have an important role in lithium neuroprotection. This study provides new insights into the neural protective mechanisms of lithium chloride.« less

Characterization of Pseudomonas putida Genes Responsive to Nutrient Limitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syn, Chris K.; Magnuson, Jon K.; Kingsley, Mark T.

2004-06-01

The low bioavailability of nutrients and oxygen in the soil environment has hampered successful expression of biodegradation/biocontrol genes that are driven by promoters highly active during routine laboratory conditions of high nutrient- and oxygen-availability. Hence, in the present study, expression of the gus-tagged genes in 12 Tn5-gus mutants of the soil microbe Pseudomonas putida PNL-MK25 was examined under various conditions chosen to mimic the soil environment: low carbon, phosphate, nitrate, or oxygen, and in the rhizosphere. Based on their expression profiles, three nutrient-responsive mutant (NRM) strains, NRM5, NRM7, and NRM17, were selected for identification of the tagged genes. In themore » mutant strain NRM5, expression of the glutamate dehydrogenase (gdhA) gene was increased between 4.9- to 26.4-fold under various low nutrient conditions. In NRM7, expression of the novel NADPH:quinone oxidoreductase-like (nql) gene was consistently amongst the highest and was synergistically upregulated by low nutrient and anoxic conditions. The cyoD gene in NRM17, which encodes the fourth subunit of the cytochrome o ubiquinol oxidase complex, had decreased expression in low nutrient conditions but its absolute expression levels was still amongst the highest. Additionally, it was independent of oxygen availability, in contrast to that in E. coli.« less

Effects of Organic Amendments on Microbiota Associated with the Culex nigripalpus Mosquito Vector of the Saint Louis Encephalitis and West Nile Viruses.

PubMed

Duguma, Dagne; Hall, Michael W; Smartt, Chelsea T; Neufeld, Josh D

2017-01-01

Pollution from nutrients in aquatic habitats has been linked to increases in disease vectors, including mosquitoes and other pestiferous insects. One possibility is that changes in mosquito microbiomes are impacted by nutrient enrichments and that these changes affect various traits, including larval development, susceptibility to larval control agents, and susceptibility of the adult mosquitoes to pathogens. We tested this hypothesis using field mesocosms supplemented with low- and high-organic-nutrient regimens and then sampled microbial communities associated with the naturally colonizing Culex nigripalpus mosquito vector. By high-throughput sequencing of 16S rRNA gene sequences, we found no significant differences in overall microbial communities associated with sampled mosquitoes, despite detecting discernible differences in environmental variables, including pH, dissolved oxygen, and nutrient amendments. Nevertheless, indicator species analysis revealed that members of the Clostridiales were significantly associated with mosquitoes that originated from high-nutrient enrichments. In contrast, members of the Burkholderiales were associated with mosquitoes from the low-nutrient enrichment. High bacterial variability associated with the life stages of the C. nigripalpus was largely unaffected by levels of nutrient enrichments that impacted larval microbial resources, including bacteria, ciliates, and flagellates in the larval environments. IMPORTANCE Mosquito microbiota provide important physiological and ecological attributes to mosquitoes, including an impact on their susceptibility to pathogens, fitness, and sensitivity to mosquito control agents. Culex nigripalpus mosquito populations transmit various pathogens, including the Saint Louis and West Nile viruses, and proliferate in nutrient-rich environments, such as in wastewater treatment wetlands. Our study examined whether increases in nutrients within larval mosquito developmental habitats impact microbial communities associated with C. nigripalpus mosquitoes. We characterized the effects of organic enrichments on microbiomes associated with C. nigripalpus mosquitoes and identified potential bacterial microbiota that will be further investigated for whether they alter mosquito life history traits and for their potential role in the development of microbial-based control strategies.

Nutrient Digestibility and Metabolizable Energy Content of Mucuna pruriens Whole Pods Fed to Growing Pelibuey Lambs

PubMed Central

Loyra-Tzab, Enrique; Sarmiento-Franco, Luis Armando; Sandoval-Castro, Carlos Alfredo; Santos-Ricalde, Ronald Herve

2013-01-01

The nutrient digestibility, nitrogen balance and in vivo metabolizable energy supply of Mucuna pruriens whole pods fed to growing Pelibuey lambs was investigated. Eight Pelibuey sheep housed in metabolic crates were fed increasing levels of Mucuna pruriens pods: 0 (control), 100 (Mucuna100), 200 (Mucuna200) and 300 (Mucuna300) g/kg dry matter. A quadratic (p<0.002) effect was observed for dry matter (DM), neutral detergent fibre (aNDF), nitrogen (N) and gross energy (GE) intakes with higher intakes in the Mucuna100 and Mucuna200 treatments. Increasing M. pruriens in the diets had no effect (p>0.05) on DM and GE apparent digestibility (p<0.05). A linear reduction in N digestibility and N retention was observed with increasing mucuna pod level. This effect was accompanied by a quadratic effect (p<0.05) on fecal-N and N-balance which were higher in the Mucuna100 and Mucuna200 treatments. Urine-N excretion, GE retention and dietary estimated nutrient supply (metabolizable protein and metabolizable energy) were not affected (p>0.05). DM, N and GE apparent digestibility coefficient of M. pruriens whole pods obtained through multiple regression equations were 0.692, 0.457, 0.654 respectively. In vivo DE and ME content of mucuna whole pod were estimated in 11.0 and 9.7 MJ/kg DM. It was concluded that whole pods from M. pruriens did not affect nutrient utilization when included in an mixed diet up to 200 g/kg DM. This is the first in vivo estimation of mucuna whole pod ME value for ruminants. PMID:25049876

Nutrient digestibility response to sugarcane bagasse addition and corn particle size in normal and high Na diets for broilers.

PubMed

Kheravii, S K; Swick, R A; Choct, M; Wu, S-B

2018-04-01

Improving diet digestibility is important to the broiler industry. Therefore, this study focused on optimizing the physical structure of feed ingredients and addition of dietary fiber as strategies to improve nutrient digestibility in low and high sodium diets. A total of 672 day-old Ross 308 male broilers was allocated to 48 pens using a 2 × 2 × 2 factorial arrangement of treatments with 2 particle sizes of corn (coarse 3,576 μm or fine 1,113 μm geometric mean diameter), 2 levels of sugarcane bagasse (SB) (0 or 2%), and 2 levels of Na (0.16 or 0.4%). Protein digestibility coefficient was measured using pooled distal ileal digesta of 3 birds per pen on d 24. Meanwhile, starch and gross energy digestibility coefficients were measured using pooled duodenal, distal jejunal, and distal ileal digesta of 3 birds per pen on d 24. Coarsely ground corn (CC) resulted in improved ileal protein digestibility (P < 0.05). Addition of 2% SB increased starch digestibility in the duodenum (P < 0.05), distal jejunum (P < 0.001), and distal ileum (P < 0.001), and increased protein digestibility in distal ileum (P < 0.01). A significant particle size × SB × Na interaction was observed for ileal energy digestibility (P < 0.05). The SB increased ileal energy digestibility only in birds fed the diet with finely ground corn (FC) and 0.16% Na. These findings demonstrate that SB and CC are able to improve nutrient digestibility. It can be recommended for the poultry industry to use SB and coarsely ground corn in feed to improve the utilization of nutrients.

Biological potential of extraterrestrial materials. 2. Microbial and plant responses to nutrients in the Murchison carbonaceous meteorite

NASA Technical Reports Server (NTRS)

Mautner, M. N.; Conner, A. J.; Killham, K.; Deamer, D. W.

1997-01-01

Meteoritic materials are investigated as potential early planetary nutrients. Aqueous extracts of the Murchison C2 carbonaceous meteorite are utilized as a sole carbon source by microorganisms, as demonstrated by the genetically modified Pseudomonas fluorescence equipped with the lux gene. Nutrient effects are observed also with the soil microorganisms Nocardia asteroides and Arthrobacter pascens that reach populations up to 5 x 10(7) CFU/ml in meteorite extracts, similar to populations in terrestrial soil extracts. Plant tissue cultures of Asparagus officinalis and Solanum tuberosum (potato) exhibit enhanced pigmentation and some enhanced growth when meteorite extracts are added to partial nutrient media, but inhibited growth when added to full nutrient solution. The meteorite extracts lead to large increases in S, Ca, Mg, and Fe plant tissue contents as shown by X-ray fluorescence, while P, K, and Cl contents show mixed effects. In both microbiological and plant tissue experiments, the nutrient and inhibitory effects appear to be best balanced for growth at about 1:20 (extracted solid : H2O) ratios. The results suggest that solutions in cavities in meteorites can provide efficient concentrated biogenic and early nutrient environments, including high phosphate levels, which may be the limiting nutrient. The results also suggest that carbonaceous asteroid resources can sustain soil microbial activity and provide essential macronutrients for future space-based ecosystems.

Does infection tilt the scales? Disease effects on the mass balance of an invertebrate nutrient recycler.

PubMed

Narr, Charlotte F; Frost, Paul C

2015-12-01

While parasites are increasingly recognized as important components of ecosystems, we currently know little about how they alter ecosystem nutrient availability via host-mediated nutrient cycling. We examined whether infection alters the flow of nutrients through hosts and whether such effects depend upon host diet quality. To do so, we compared the mass specific nutrient (i.e., nitrogen and phosphorus) release rates, ingestion rates, and elemental composition of uninfected Daphnia to those infected with a bacterial parasite, P. ramosa. N and P release rates were increased by infection when Daphnia were fed P-poor diets, but we found no effect of infection on the nutrient release of individuals fed P-rich diets. Calculations based on the first law of thermodynamics indicated that infection should increase the nutrient release rates of Daphnia by decreasing nutrient accumulation rates in host tissues. Although we found reduced nutrient accumulation rates in infected Daphnia fed all diets, this reduction did not increase the nutrient release rates of Daphnia fed the P-rich diet because infected Daphnia fed this diet ingested nutrients more slowly than uninfected hosts. Our results thus indicate that parasites can significantly alter the nutrient use of animal consumers, which could affect the availability of nutrients in heavily parasitized environments.

Algal biofuels from urban wastewaters: maximizing biomass yield using nutrients recycled from hydrothermal processing of biomass.

PubMed

Selvaratnam, T; Pegallapati, A K; Reddy, H; Kanapathipillai, N; Nirmalakhandan, N; Deng, S; Lammers, P J

2015-04-01

Recent studies have proposed algal cultivation in urban wastewaters for the dual purpose of waste treatment and bioenergy production from the resulting biomass. This study proposes an enhancement to this approach that integrates cultivation of an acidophilic strain, Galdieria sulphuraria 5587.1, in a closed photobioreactor (PBR); hydrothermal liquefaction (HTL) of the wet algal biomass; and recirculation of the nutrient-rich aqueous product (AP) of HTL to the PBR to achieve higher biomass productivity than that could be achieved with raw wastewater. The premise is that recycling nutrients in the AP can maintain optimal C, N and P levels in the PBR to maximize biomass growth to increase energy returns. Growth studies on the test species validated growth on AP derived from HTL at temperatures from 180 to 300°C. Doubling N and P concentrations over normal levels in wastewater resulted in biomass productivity gains of 20-25% while N and P removal rates also doubled. Copyright © 2015 Elsevier Ltd. All rights reserved.

Plant responses to elevated atmospheric CO/sub 2/ with emphasis on belowground processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norby, R.J.; Luxmoore, R.J.; O'Neill, E.G.

1984-12-01

Consideration of the interrelationships between carbon, water, and nutrient pathways in soil-plant systems has led to the hypothesis that stimulation of root and rhizosphere processes by elevated levels of CO/sub 2/ will increase nutrient availability and lead to an increase in plant growth. Several experiments were conducted to investigate the effects of CO/sub 2/ concentration on carbon allocation, root exudation, nitrogen utilization, and microbial responses, as well as overall plant growth and nutrient utilization. Increases in the growth of yellow-poplar (Liriodendron tulipifera L.) seedlings in response to elevated CO/sub 2/ were demonstrated even when the plants were under apparent nutrientmore » limitation in a forest soil. The proportion of photosynthetically fixed carbon that was allocated to the roots of yellow-poplar and hazel alder (Alnus serrulata (Ait.) Willd.) seedlings was greater at 700 ppM CO/sub 2/ than at ambient CO/sub 2/. Exudation of carbon from yellow-poplar roots also tended to be higher in elevated CO/sub 2/. Responses of rhizosphere microbial populations to elevated CO/sub 2/ were inconsistent, but there was a trend toward relatively fewer ammonium oxidizers, nitrite oxidizers, and phosphate solubilizers in the rhizosphere population of yellow-poplar seedlings grown in 700 ppM CO/sub 2/ compared to that of seedlings grown in ambient CO/sub 2/. Other observed trends included increased nodulation and nitrogenase activity and decreased nitrate reductase activity in hazel alder seedlings in elevated CO/sub 2/. Net uptake of some essential plant nutrients, aluminum, and other trace metals by Virginia pine (Pinus virginiana Mill.) increased with increasing CO/sub 2/ concentration. There was less leaching of some nutrients from soil-plant systems with Virginia pine and yellow-poplar seedlings but increased leaching of zinc. 123 references, 16 figures, 17 tables.« less

Nutrient changes and antinutrient contents of beniseed and beniseed soup during cooking using a Nigerian traditional method.

PubMed

Agiang, M A; Umoh, I B; Essien, A I; Eteng, M U

2010-10-15

Evaluations of the effect of prolong cooking on the nutrient and antinutrient composition ofbeniseed and beniseed soup were carried out in this study. Proximate, mineral, vitamin A and C and antinutrient compositions of raw beniseed (BS-R), beniseed boiled (BSB) for 15, 30, 45 and 60 min and beniseed soup (BSS) cooked for the same intervals of time were assessed. Results of the proximate composition analyses showed that raw and boiled beniseed had lower moisture content (5.39-5.51%) than beniseed soups (10.06-15.20%). Nitrogen-free extract (total carbohydrates), fats and phosphorus contents were improved in both the boiled beniseed and beniseed soup while calcium and potassium were increased in the boiled seeds and soup samples respectively. Moisture (in the raw and boiled beniseed), ash, magnesium, zinc, iron contents in both the seed and soup were unchanged in all the samples. Vitamins A and C levels of both boiled beniseed and beniseed soup samples were reduced with increase in cooking time. Beniseed soup had higher protein contents than both the raw and boiled beniseed which decreased with increase in cooking time. Beniseed samples provided good sources of energy (572.97-666.05 kcal/100 g). Except for phytate, the levels of antinutrients tested were lower in the raw and boiled beniseed than in the soup samples which decreased with increase in cooking time. The results are discussed with reference to the effect of prolonged cooking on the nutrient requirements of consumers.

The Effects of Nutrient Enrichment and Herbivore Abundance on the Ability of Turf Algae to Overgrow Coral in the Caribbean

PubMed Central

Vermeij, Mark J. A.; van Moorselaar, Imke; Engelhard, Sarah; Hörnlein, Christine; Vonk, Sophie M.; Visser, Petra M.

2010-01-01

Turf algae are multispecies communities of small marine macrophytes that are becoming a dominant component of coral reef communities around the world. To assess the impact of turf algae on corals, we investigated the effects of increased nutrients (eutrophication) on the interaction between the Caribbean coral Montastraea annularis and turf algae at their growth boundary. We also assessed whether herbivores are capable of reducing the abundance of turf algae at coral-algae boundaries. We found that turf algae cause visible (overgrowth) and invisible negative effects (reduced fitness) on neighbouring corals. Corals can overgrow neighbouring turf algae very slowly (at a rate of 0.12 mm 3 wk−1) at ambient nutrient concentrations, but turf algae overgrew corals (at a rate of 0.34 mm 3 wk−1) when nutrients were experimentally increased. Exclusion of herbivores had no measurable effect on the rate turf algae overgrew corals. We also used PAM fluorometry (a common approach for measuring of a colony's “fitness”) to detect the effects of turf algae on the photophysiology of neighboring corals. Turf algae always reduced the effective photochemical efficiency of neighbouring corals, regardless of nutrient and/or herbivore conditions. The findings that herbivores are not capable of controlling the abundance of turf algae and that nutrient enrichment gives turf algae an overall competitive advantage over corals together have serious implications for the health of Caribbean coral reef systems. At ambient nutrient levels, traditional conservation measures aimed at reversing coral-to-algae phase shifts by reducing algal abundance (i.e., increasing herbivore populations by establishing Marine Protected Areas or tightening fishing regulations) will not necessarily reduce the negative impact of turf algae on local coral communities. Because turf algae have become the most abundant benthic group on Curaçao (and likely elsewhere in the Caribbean), new conservation strategies are required to mitigate their negative impact on coral communities. PMID:21179215

Soil Respiration and Belowground Carbon Stores Among Salt Marshes Subjected to Increasing Watershed Nitrogen Loadings in Southern New England

EPA Science Inventory

Coastal salt marshes are ecosystems located between the uplands and sea, and because of their location are subject to increasing watershed nutrient loadings and rising sea levels. Residential development along the coast is intense, and there is a significant relationship between...

Response of estuarine biofilm microbial community development to changes in dissolved oxygen and nutrient concentrations.

PubMed

Nocker, Andreas; Lepo, Joe Eugene; Martin, Linda Lin; Snyder, Richard Allan

2007-10-01

The information content and responsiveness of microbial biofilm community structure, as an integrative indicator of water quality, was assessed against short-term changes in oxygen and nutrient loading in an open-water estuarine setting. Biofilms were grown for 7-day periods on artificial substrates in the Pensacola Bay estuary, Florida, in the vicinity of a wastewater treatment plant (WWTP) outfall and a nearby reference site. Substrates were deployed floating at the surface and near the benthos in 5.4 m of water. Three sampling events covered a 1-month period coincident with declining seasonal WWTP flow and increasing dissolved oxygen (DO) levels in the bottom waters. Biomass accumulation in benthic biofilms appeared to be controlled by oxygen rather than nutrients. The overriding effect of DO was also seen in DNA fingerprints of community structure by terminal restriction fragment length polymorphism (T-RFLP) of amplified 16S rRNA genes. Ribotype diversity in benthic biofilms at both sites dramatically increased during the transition from hypoxic to normoxic. Terminal restriction fragment length polymorphism patterns showed pronounced differences between benthic and surface biofilm communities from the same site in terms of signal type, strength, and diversity, but minor differences between sites. Sequencing of 16S rRNA gene clone libraries from benthic biofilms at the WWTP site suggested that low DO levels favored sulfate-reducing prokaryotes (SRP), which decreased with rising oxygen levels and increasing overall diversity. A 91-bp ribotype in the CfoI-restricted 16S rRNA gene T-RFLP profiles, indicative of SRP, tracked the decrease in relative SRP abundance over time.

Induced epidermal permeability modulates resistance and susceptibility of wheat seedlings to herbivory by Hessian fly larvae

PubMed Central

Williams, Christie E.; Nemacheck, Jill A.; Shukle, John T.; Subramanyam, Subhashree; Saltzmann, Kurt D.; Shukle, Richard H.

2011-01-01

Salivary secretions of neonate Hessian fly larvae initiate a two-way exchange of molecules with their wheat host. Changes in properties of the leaf surface allow larval effectors to enter the plant where they trigger plant processes leading to resistance and delivery of defence molecules, or susceptibility and delivery of nutrients. To increase understanding of the host plant's response, the timing and characteristics of the induced epidermal permeability were investigated. Resistant plant permeability was transient and limited in area, persisting just long enough to deliver defence molecules before gene expression and permeability reverted to pre-infestation levels. The abundance of transcripts for GDSL-motif lipase/hydrolase, thought to contribute to cuticle reorganization and increased permeability, followed the same temporal profile as permeability in resistant plants. In contrast, susceptible plants continued to increase in permeability over time until the entire crown of the plant became a nutrient sink. Permeability increased with higher infestation levels in susceptible but not in resistant plants. The ramifications of induced plant permeability on Hessian fly populations are discussed. PMID:21659664

Effect of combined xylanase and phytase on growth performance, apparent total tract digestibility, and carcass characteristics in growing pigs fed corn-based diets containing high-fiber coproducts.

PubMed

Jang, Y D; Wilcock, P; Boyd, R D; Lindemann, M D

2017-09-01

Phytate has been shown to be an antinutrient, and the feeding of high levels of phytase can break down phytate to improve nutrient utilization and pig performance. Dietary xylanase targets arabinoxylan breakdown, thereby improving energy utilization in pigs. However, the effects of simultaneous supplementation have not been clearly determined. Crossbred pigs ( = 45; mean initial weight, 26.4 ± 0.2 kg) were allotted to 1 of 9 treatments to evaluate the effects of both xylanase (endo-1,4-β xylanase [EC 3.2.1.8]) and phytase (6-phytase [EC 3.1.3.26]) supplementation as follows: 1) positive control (PC), a corn-soybean meal-based diet with 15% corn distillers dried grains with solubles, 15% wheat middlings, and 13% corn germ meal; 2) negative control (NC), ME was reduced by 103 kcal/kg from the PC diet by replacement of fat with corn starch; 3) NC + phytase (500 phytase units (FTU)/kg diet); 4) NC + phytase (1,000 FTU/kg diet); 5) NC + phytase (2,000 FTU/kg diet); 6) NC + xylanase (24,000 xylanase units [BXU]/kg diet); 7) NC + phytase (500 FTU/kg diet) + xylanase (24,000 BXU/kg diet); 8) NC + phytase (1,000 FTU/kg diet) + xylanase (24,000 BXU/kg diet); and 9) NC + phytase (2,000 FTU/kg diet) + xylanase (24,000 BXU/kg diet). All diets were formulated to meet nutrient requirements before phytase and xylanase addition to the diets. There were no significant interactions between xylanase and phytase supplementation on growth performance, carcass characteristics, and apparent total tract digestibility (ATTD). The ADG ( < 0.01, quadratic) and G:F ( < 0.05, linear) for the overall period increased as phytase level increased. The ATTD of P increased as phytase supplementation level increased ( < 0.05, linear and quadratic). The ATTD of DM, NDF, ether extract ( < 0.05), and hemicellulose ( = 0.05) increased quadratically as phytase level increased. Estimated carcass lean percentage and lean gain increased ( < 0.05, linear) as phytase level increased. Xylanase supplementation had no effect on growth performance, ATTD, and carcass characteristics. The results demonstrated an improved nutrient digestibility, performance, and carcass response to phytase supplementation beyond P provision because all diets exceeded current P requirement estimates based on standardized total tract digestible P.

Advancing Analysis of Spatio-Temporal Variations of Soil Nutrients in the Water Level Fluctuation Zone of China’s Three Gorges Reservoir Using Self-Organizing Map

PubMed Central

Ye, Chen; Li, Siyue; Yang, Yuyi; Shu, Xiao; Zhang, Jiaquan; Zhang, Quanfa

2015-01-01

The ~350 km2 water level fluctuation zone (WLFZ) in the Three Gorges Reservoir (TGR) of China, situated at the intersection of terrestrial and aquatic ecosystems, experiences a great hydrological change with prolonged winter inundation. Soil samples were collected in 12 sites pre- (September 2008) and post submergence (June 2009) in the WLFZ and analyzed for soil nutrients. Self-organizing map (SOM) and statistical analysis including multi-way ANOVA, paired-T test, and stepwise least squares multiple regression were employed to determine the spatio-temporal variations of soil nutrients in relation to submergence, and their correlations with soil physical characteristics. Results showed significant spatial variability in nutrients along ~600 km long shoreline of the TGR before and after submergence. There were higher contents of organic matter, total nitrogen (TN), and nitrate (NO3-) in the lower reach and total phosphorus (TP) in the upper reach that were primarily due to the spatial variations in soil particle size composition and anthropogenic activities. Submergence enhanced soil available potassium (K), while significantly decreased soil N, possibly due to the alterations of soil particle size composition and increase in soil pH. In addition, SOM analysis determined important roles of soil pH value, bulk density, soil particle size (i.e., silt and sand) and nutrients (TP, TK, and AK) on the spatial and temporal variations in soil quality. Our results suggest that urban sewage and agricultural runoffs are primary pollutants that affect soil nutrients in the WLFZ of TGR. PMID:25789612

Research to Inform Nutrient Thresholds and Prioritization of Watersheds for Nutrient Management

EPA Science Inventory

The information in this presentation focuses on SSWR's 4.02 project, which will advance the science needed to inform decisions to prioritize watersheds and nutrient sources for nutrient management and define appropriate nutrient levels for the nation’s waters, two importan...

Lianas always outperform tree seedlings regardless of soil nutrients: results from a long-term fertilization experiment.

PubMed

Pasquini, Sarah C; Wright, S Joseph; Santiago, Louis S

2015-07-01

Lianas are a prominent growth form in tropical forests, and there is compelling evidence that they are increasing in abundance throughout the Neotropics. While recent evidence shows that soil resources limit tree growth even in deep shade, the degree to which soil resources limit lianas in forest understories, where they coexist with trees for decades, remains unknown. Regardless, the physiological underpinnings of soil resource limitation in deeply shaded tropical habitats remain largely unexplored for either trees or lianas. Theory predicts that lianas should be more limited by soil resources than trees because they occupy the quick-return end of the "leaf economic spectrum," characterized by high rates of photosynthesis, high specific leaf area, short leaf life span, affinity to high-nutrient sites, and greater foliar nutrient concentrations. To address these issues, we asked whether soil resources (nitrogen, phosphorus, and potassium), alone or in combination, applied experimentally for more than a decade would cause significant changes in the morphology or physiology of tree and liana seedlings in a lowland tropical forest. We found evidence for the first time that phosphorus limits the photosynthetic performance of both trees and lianas in deeply shaded understory habitats. More importantly, lianas always showed significantly greater photosynthetic capacity, quenching, and saturating light levels compared to trees across all treatments. We found little evidence for nutrient x growth form interactions, indicating that lianas were not disproportionately favored in nutrient-rich habitats. Tree and liana seedlings differed markedly for six key morphological traits, demonstrating that architectural differences occurred very early in ontogeny prior to lianas finding a trellis (all seedlings were self-supporting). Overall, our results do not support nutrient loading as a mechanism of increasing liana abundance in the Neotropics. Rather, our finding that lianas always outperform trees, in terms of photosynthetic processes and under contrasting rates of resource supply of macronutrients, will allow lianas to increase in abundance if disturbance and tree turnover rates are increasing in Neotropical forests as has been suggested.

Coastal ocean acidification: The other eutrophication problem

EPA Science Inventory

Increased nutrient loading into estuaries causes the accumulation of algal biomass, and microbial degradation of this organic matter decreases oxygen levels and contributes towards hypoxia. A second, often overlooked consequence of microbial degradation of organic matter is the p...

Vegetation composition, nutrient, and sediment dynamics along a floodplain landscape

USGS Publications Warehouse

Rybicki, Nancy B.; Noe, Gregory; Hupp, Cliff R.; Robinson, Myles

2015-01-01

Forested floodplains are important landscape features for retaining river nutrients and sediment loads but there is uncertainty in how vegetation influences nutrient and sediment retention. In order to understand the role of vegetation in nutrient and sediment trapping, we quantified species composition and the uptake of nutrients in plant material relative to landscape position and ecosystem attributes in an urban, Piedmont watershed in Virginia, USA. We investigated in situ interactions among vegetative composition, abundance, carbon (C), nitrogen (N) and phosphorus (P) fluxes and ecosystem attributes such as water level, shading, soil nutrient mineralization, and sediment deposition. This study revealed strong associations between vegetation and nutrient and sediment cycling processes at the plot scale and in the longitudinal dimension, but there were few strong patterns between these aspects at the scale of geomorphic features (levee, backswamp, and toe-slope). Patterns reflected the nature of the valley setting rather than a simple downstream continuum. Plant nutrient uptake and sediment trapping were greatest at downstream sites with the widest floodplain and lowest gradient where the hydrologic connection between the floodplain and stream is greater. Sediment trapping increased in association with higher herbaceous plant coverage and lower tree canopy density that, in turn, was associated with a more water tolerant tree community found in the lower watershed but not at the most downstream site in the watershed. Despite urbanization effects on the hydrology, this floodplain functioned as an efficient nutrient trap. N and P flux rates of herbaceous biomass and total litterfall more than accounted for the N and P mineralization flux rate, indicating that vegetation incorporated nearly all mineralized nutrients into biomass.

Competitive intra- and extracellular nutrient sensing by the transporter homologue Ssy1p

PubMed Central

Wu, Boqian; Ottow, Kim; Poulsen, Peter; Gaber, Richard F.; Albers, Eva; Kielland-Brandt, Morten C.

2006-01-01

Recent studies of Saccharomyces cerevisiae revealed sensors that detect extracellular amino acids (Ssy1p) or glucose (Snf3p and Rgt2p) and are evolutionarily related to the transporters of these nutrients. An intriguing question is whether the evolutionary transformation of transporters into nontransporting sensors reflects a homeostatic capability of transporter-like sensors that could not be easily attained by other types of sensors. We previously found SSY1 mutants with an increased basal level of signaling and increased apparent affinity to sensed extracellular amino acids. On this basis, we propose and test a general model for transporter- like sensors in which occupation of a single, central ligand binding site increases the activation energy needed for the conformational shift between an outward-facing, signaling conformation and an inward-facing, nonsignaling conformation. As predicted, intracellular leucine accumulation competitively inhibits sensing of extracellular amino acids. Thus, a single sensor allows the cell to respond to changes in nutrient availability through detection of the relative concentrations of intra- and extracellular ligand. PMID:16651382

Induction of Crassulacean Acid Metabolism in Mesembryanthemum crystallinum by High Salinity: Mass Increase and de Novo Synthesis of PEP-Carboxylase 1

PubMed Central

Höfner, Roswitha; Vazquez-Moreno, Luz; Winter, Klaus; Bohnert, Hans J.; Schmitt, Jürgen M.

1987-01-01

Intact plants of the halophilic species Mesembryanthemum crystallinum were induced to exhibit Crassulacean acid metabolism by irrigation with nutrient solution containing 500 millimolar NaCl. During the induction period, the extractable activity of phosphoenolpyruvate carboxylase (PEPcase) increased approximately 40-fold. This increase was linearly correlated with a mass increase of PEPcase protein as measured by single radial immunodiffusion. De novo synthesis of PEPcase protein was shown by immunoprecipitation of the newly synthesized, radioactively labeled protein in leaf discs from salt-treated plants. Nontreated plants were characterized by a low level of the enzyme and low rates of PEPcase synthesis. Synthesis of this enzyme in leaf discs was correlated with the concentration of NaCl in the nutrient solution during growth. Images Fig. 1 Fig. 2 Fig. 3 PMID:16665363

Interactions between temperature and nutrients across levels of ecological organization.

PubMed

Cross, Wyatt F; Hood, James M; Benstead, Jonathan P; Huryn, Alexander D; Nelson, Daniel

2015-03-01

Temperature and nutrient availability play key roles in controlling the pathways and rates at which energy and materials move through ecosystems. These factors have also changed dramatically on Earth over the past century as human activities have intensified. Although significant effort has been devoted to understanding the role of temperature and nutrients in isolation, less is known about how these two factors interact to influence ecological processes. Recent advances in ecological stoichiometry and metabolic ecology provide a useful framework for making progress in this area, but conceptual synthesis and review are needed to help catalyze additional research. Here, we examine known and potential interactions between temperature and nutrients from a variety of physiological, community, and ecosystem perspectives. We first review patterns at the level of the individual, focusing on four traits--growth, respiration, body size, and elemental content--that should theoretically govern how temperature and nutrients interact to influence higher levels of biological organization. We next explore the interactive effects of temperature and nutrients on populations, communities, and food webs by synthesizing information related to community size spectra, biomass distributions, and elemental composition. We use metabolic theory to make predictions about how population-level secondary production should respond to interactions between temperature and resource supply, setting up qualitative predictions about the flows of energy and materials through metazoan food webs. Last, we examine how temperature-nutrient interactions influence processes at the whole-ecosystem level, focusing on apparent vs. intrinsic activation energies of ecosystem processes, how to represent temperature-nutrient interactions in ecosystem models, and patterns with respect to nutrient uptake and organic matter decomposition. We conclude that a better understanding of interactions between temperature and nutrients will be critical for developing realistic predictions about ecological responses to multiple, simultaneous drivers of global change, including climate warming and elevated nutrient supply. © 2014 John Wiley & Sons Ltd.

Effects of elevated atmospheric carbon dioxide concentrations on water and acid requirements of soybeans grown in a recirculating hydroponic system

NASA Technical Reports Server (NTRS)

Mackowiak, C. L.; Wheeler, R. M.; Lowery, W.; Sager, J. C.

1990-01-01

Establishing mass budgets of various crop needs, i.e. water and nutrients, in different environments is essential for the Controlled Ecological Life Support System (CELSS). The effects of CO2 (500 and 1000 umol mol (exp -1)) on water and acid use (for pH control) by soybeans in a recirculating hydroponic system were examined. Plants of cvs. McCall and Pixie were grown for 90 days using the nutrient film technique (NFT) and a nitrate based nutrient solution. System acid use for both CO2 levels peaked near 4 weeks during a phase of rapid vegetative growth, but acid use decreased more rapidly under 500 compared to 1000 umol mol (exp GR) CO2. Total system water use by 500 and 1000 umol mol (exp -1) plants was similar, leaving off at 5 weeks and declining as plants senesced (ca. 9 weeks). However, single leaf transpiration rates were consistently lower at 1000 umol mol (exp -1). The data suggest that high CO2 concentrations increase system acid (and nutrient) use because of increased vegetative growth, which in turn negates the benefit of reduced water use (lower transpiration rates) per unit leaf area.

Comparative validity of the ASSO-Food Frequency Questionnaire for the web-based assessment of food and nutrients intake in adolescents.

PubMed

Tabacchi, Garden; Filippi, Anna Rita; Breda, João; Censi, Laura; Amodio, Emanuele; Napoli, Giuseppe; Bianco, Antonino; Jemni, Monèm; Firenze, Alberto; Mammina, Caterina

2015-01-01

A new web-based food frequency questionnaire (the ASSO-FFQ) was developed within the ASSO Project funded by the Italian Ministry of Health. The aim of the present study is to assess the validity of the ASSO-FFQ at food groups, energy, and nutrients level. The validation study compared the ASSO-FFQ against a weighted food record (WFR) measuring foods, beverages and supplements intake, compiled during the week following the ASSO-FFQ administration. Ninety-two subjects aged 14-17, recruited from secondary schools in Palermo (Italy), completed the ASSO-FFQ and WFR. The intake of 24 food groups, energy, and 52 nutrients were taken as main outcomes. Tests for paired observations, Spearman and Pearson's correlation coefficients (cc), kappa statistics and classification in quintiles, Bland-Altman plots and multiple regressions, on untransformed and transformed data were used for the statistical analysis. High cc (≥0.40) were found for soft drinks, milk, tea/coffee, vegetables, and lactose; fair energy-adjusted cc (0.25-0.40) for water, alcoholic drinks, breakfast cereals, fishery products, savory food, fruit juice, eggs, and 19 nutrients. The subjects classified in the same or adjacent quintile for food groups ranged from 40% (alcoholic drinks) to 100% (dried fruit); for energy and nutrients from 43% (phosphorus, thiamin, niacin) to 77% (lactose). Mean differences were not significant for water, soft drinks, meat, sweets, animal fats, milk and white bread, and vitamin B12 and folate. Limits of Agreement were broad for all food groups and nutrients. School, gender, alcohol consumption and between meals mainly affected most food groups' intake differences. Gender stratification showed females had increased Pearson's cc for energy and 28 nutrients, such as almost all fats, carbohydrates, vitamins and minerals. The ASSO-FFQ could be applied in epidemiological studies for the assessment of dietary consumption in adolescents to adequately rank food, energy and nutrient intakes at a group level.

The effects of soil moisture, texture, and nutrient levels on the growth of black walnut.

Treesearch

Richard E. Dickson

1971-01-01

Black walnut seedlings grown in a clay loam and sandy soil were subjected to two soil moisture regimes and three fertility levels. Fertilization increased growth only under most conditions. Under draught, fertilization retarded growth in the sand. Nitrogen was the element primarily responsible for the greater growth under moist conditions.

Use of glucose biosensors to measure extracellular glucose exudation by intertidal microphytobenthos in southern Tasmania.

PubMed

McMinn, Andrew; Lee, Shihong

2018-06-01

Micro glucose biosensors were used to measure net extracellular glucose produced by natural microphytobenthos and three diatom cultures (Amphora coffeaeformis, Navicula menisculus, Nitzschia longissima) from southern Tasmania, Australia. They were exposed to a light gradient in either nutrient-replete or nutrient-limiting conditions. Glucose exudation in the natural communities increased with increased light but the response in the cultures was variable. Similarly, nutrient-replete conditions elicited lower rates of glucose exudation in the natural communities but produced variable species-specific responses in the cultures. Increased glucose exudation mostly correlated with a reduction in maximum quantum yield (F v /F m ). The same trend was observed in the natural communities for relative maximum electron transfer rates (rETR max ) but responses in the cultures were again variable and species-specific. Responses of the three species to increased light and nutrient deficiency were variable, although glucose exudation, F v /F m and rETR max was mostly lower in the nutrient-limited media. In a second set of experiments species/communities were treated with/without antibiotics. In the dark, glucose concentrations in treatments with antibiotics remained unchanged, while in those with bacteria, it fell rapidly. In the sediment communities, glucose consumption in the dark was ~25% the rate of exudation at the highest light level. In culture, exudation rates were up to 100% greater than those with active bacteria. Rates of glucose consumption in the dark in the antibiotic-treated samples were negligible and up to 10 4 times lower than those with active bacteria. These results demonstrate the important role extracellular glucose exudation has on maintaining an active microbial loop. © 2018 Phycological Society of America.

Tracking of energy and nutrient intakes from adolescence to young adulthood: the experiences of the Young Hearts Project, Northern Ireland.

PubMed

Gallagher, A M; Robson, P J; Livingstone, M B E; Cran, G W; Strain, J J; Murray, L J; Savage, J M; Boreham, C A G

2006-12-01

To assess tracking of energy and nutrient intakes between adolescence and young adulthood. Longitudinal study of a random sample of adolescents (aged 15 years at baseline). The extent of tracking of dietary intakes (assessed by diet history) was investigated using weighted kappa statistics (kappa). Northern Ireland population survey. Adolescents who participated in the Young Hearts Project, Northern Ireland at age 15 years, and subsequently at young adulthood aged between 20 and 25 years (n=245 males, n=231 females). Despite overall increases in height and weight (both P<0.001), increases in body mass index in males (P<0.001) and body fatness in females (P<0.001), median reported intakes of energy (kJ kg(-1) day(-1)), carbohydrate (g day(-1)) and fat (g day(-1)) decreased (all P<0.001) over time. Expressed as nutrient densities (per MJ), diets at young adulthood were overall richer in thiamin, vitamin B6, total folate (all P<0.001), vitamin C (P<0.01) and vitamin D (P<0.05). Whereas the nutrient density of the males' diets decreased over time for calcium (P<0.05) and vitamin A (P<0.001), iron and riboflavin densities increased in the females' diet (P<0.001). Tracking of energy (MJ day(-1)) and nutrient intakes (expressed per MJ day(-1)) at the individual level was only poor to fair (all kappa<0.25), indicating substantial drift of subjects between the low, medium and high classes of intake with increasing age. These data suggest that individual dietary patterns exhibited at 15 years of age are unlikely to be predictive of dietary intakes at young adulthood.

The effect of nitrogen availability and water conditions on competition between a facultative CAM plant and an invasive grass.

PubMed

Yu, Kailiang; D'Odorico, Paolo; Carr, David E; Personius, Ashden; Collins, Scott L

2017-10-01

Plants with crassulacean acid metabolism (CAM) are increasing their abundance in drylands worldwide. The drivers and mechanisms underlying the increased dominance of CAM plants and CAM expression (i.e., nocturnal carboxylation) in facultative CAM plants, however, remain poorly understood. We investigated how nutrient and water availability affected competition between Mesembryanthemum crystallinum (a model facultative CAM species) and the invasive C 3 grass Bromus mollis that co-occur in California's coastal grasslands. Specifically we investigated the extent to which water stress, nutrients, and competition affect nocturnal carboxylation in M. crystallinum . High nutrient and low water conditions favored M. crystallinum over B. mollis , in contrast to high water conditions. While low water conditions induced nocturnal carboxylation in 9-week-old individuals of M. crystallinum , in these low water treatments, a 66% reduction in nutrient applied over the entire experiment did not further enhance nocturnal carboxylation. In high water conditions M. crystallinum both alone and in association with B. mollis did not perform nocturnal carboxylation, regardless of the nutrient levels. Thus, nocturnal carboxylation in M. crystallinum was restricted by strong competition with B. mollis in high water conditions. This study provides empirical evidence of the competitive advantage of facultative CAM plants over grasses in drought conditions and of the restricted ability of M. crystallinum to use their photosynthetic plasticity (i.e., ability to switch to CAM behavior) to compete with grasses in well-watered conditions. We suggest that a high drought tolerance could explain the increased dominance of facultative CAM plants in a future environment with increased drought and nitrogen deposition, while the potential of facultative CAM plants such as M. crystallinum to expand to wet environments is expected to be limited.

Knockout maternal adiponectin increases fetal growth in mice: potential role for trophoblast IGFBP-1.

PubMed

Qiao, Liping; Wattez, Jean-Sebastien; Lee, Samuel; Guo, Zhuyu; Schaack, Jerome; Hay, William W; Zita, Matteo Moretto; Parast, Mana; Shao, Jianhua

2016-11-01

The main objective of this study was to investigate whether maternal adiponectin regulates fetal growth through the endocrine system in the fetal compartment. Adiponectin knockout (Adipoq (-/-) ) mice and in vivo adenovirus-mediated reconstitution were used to study the regulatory effect of maternal adiponectin on fetal growth. Primary human trophoblast cells were treated with adiponectin and a specific peroxisome proliferator-activated receptor α (PPARα) agonist or antagonist to study the underlying mechanism through which adiponectin regulates fetal growth. The body weight of fetuses from Adipoq (-/-) dams was significantly greater than that of wild-type dams at both embryonic day (E)14.5 and E18.5. Adenoviral vector-mediated maternal adiponectin reconstitution attenuated the increased fetal body weight induced by maternal adiponectin deficiency. Significantly increased blood glucose, triacylglycerol and NEFA levels were observed in Adipoq (-/-) dams, suggesting that nutrient supply contributes to maternal adiponectin-regulated fetal growth. Although fetal blood IGF-1 concentrations were comparable in fetuses from Adipoq (-/-) and wild-type dams, remarkably low levels of IGF-binding protein 1 (IGFBP-1) were observed in the serum of fetuses from Adipoq (-/-) dams. IGFBP-1 was identified in the trophoblast cells of human and mouse placentas. Maternal fasting robustly increased IGFBP-1 levels in mouse placentas, while reducing fetal weight. Significantly low IGFBP-1 levels were found in placentas of Adipoq (-/-) dams. Adiponectin treatment increased IGFBP-1 levels in primary cultured human trophoblast cells, while the PPARα antagonist, MK886, abolished this stimulatory effect. These results indicate that, in addition to nutrient supply, maternal adiponectin inhibits fetal growth by increasing IGFBP-1 expression in trophoblast cells.

The Pattern of Change in the Abundances of Specific Bacterioplankton Groups Is Consistent across Different Nutrient-Enriched Habitats in Crete

PubMed Central

Fodelianakis, Stilianos; Papageorgiou, Nafsika; Pitta, Paraskevi; Kasapidis, Panagiotis; Karakassis, Ioannis

2014-01-01

A common source of disturbance for coastal aquatic habitats is nutrient enrichment through anthropogenic activities. Although the water column bacterioplankton communities in these environments have been characterized in some cases, changes in α-diversity and/or the abundances of specific taxonomic groups across enriched habitats remain unclear. Here, we investigated the bacterial community changes at three different nutrient-enriched and adjacent undisturbed habitats along the north coast of Crete, Greece: a fish farm, a closed bay within a town with low water renewal rates, and a city port where the level of nutrient enrichment and the trophic status of the habitat were different. Even though changes in α-diversity were different at each site, we observed across the sites a common change pattern accounting for most of the community variation for five of the most abundant bacterial groups: a decrease in the abundance of the Pelagibacteraceae and SAR86 and an increase in the abundance of the Alteromonadaceae, Rhodobacteraceae, and Cryomorphaceae in the impacted sites. The abundances of the groups that increased and decreased in the impacted sites were significantly correlated (positively and negatively, respectively) with the total heterotrophic bacterial counts and the concentrations of dissolved organic carbon and/or dissolved nitrogen and chlorophyll α, indicating that the common change pattern was associated with nutrient enrichment. Our results provide an in situ indication concerning the association of specific bacterioplankton groups with nutrient enrichment. These groups could potentially be used as indicators for nutrient enrichment if the pattern is confirmed over a broader spatial and temporal scale by future studies. PMID:24747897

Conserved Transcriptional Responses to Nutrient Stress in Bloom-Forming Algae

PubMed Central

Harke, Matthew J.; Juhl, Andrew R.; Haley, Sheean T.; Alexander, Harriet; Dyhrman, Sonya T.

2017-01-01

The concentration and composition of bioavailable nitrogen (N) and phosphorus (P) in the upper ocean shape eukaryotic phytoplankton communities and influence their physiological responses. Phytoplankton are known to exhibit similar physiological responses to limiting N and P conditions such as decreased growth rates, chlorosis, and increased assimilation of N and P. Are these responses similar at the molecular level across multiple species? To interrogate this question, five species from biogeochemically important, bloom-forming taxa (Bacillariophyta, Dinophyta, and Haptophyta) were grown under similar low N, low P, and replete nutrient conditions to identify transcriptional patterns and associated changes in biochemical pools related to N and P stress. Metabolic profiles, revealed through the transcriptomes of these taxa, clustered together based on species rather than nutrient stressor, suggesting that the global metabolic response to nutrient stresses was largely, but not exclusively, species-specific. Nutrient stress led to few transcriptional changes in the two dinoflagellates, consistent with other research. An orthologous group analysis examined functionally conserved (i.e., similarly changed) responses to nutrient stress and therefore focused on the diatom and haptophytes. Most conserved ortholog changes were specific to a single nutrient treatment, but a small number of orthologs were similarly changed under both N and P stress in 2 or more species. Many of these orthologs were related to photosynthesis and may represent generalized stress responses. A greater number of orthologs were conserved across more than one species under low P compared to low N. Screening the conserved orthologs for functions related to N and P metabolism revealed increased relative abundance of orthologs for nitrate, nitrite, ammonium, and amino acid transporters under N stress, and increased relative abundance of orthologs related to acquisition of inorganic and organic P substrates under P stress. Although the global transcriptional responses were dominated by species-specific changes, the analysis of conserved responses revealed functional similarities in resource acquisition pathways among different phytoplankton taxa. This overlap in nutrient stress responses observed among species may be useful for tracking the physiological ecology of phytoplankton field populations. PMID:28769884

The efficacy of using exogenous enzymes cocktail on production, egg quality, egg nutrients and blood metabolites of laying hens fed distiller's dried grains with solubles.

PubMed

Abd El-Hack, M E; Chaudhry, M T; Mahrose, K M; Noreldin, A; Emam, M; Alagawany, M

2018-04-01

An experiment was performed using 120 Hisex Brown laying hens for evaluating the effects of different inclusion levels of corn distiller's dried grains with solubles (DDGS) as a replacement of soybean meal (SBM) with or without enzyme cocktail on performance, egg quality, egg nutrients and blood metabolites in laying hens through 22-42 weeks of age. A 4 × 2 factorial design experiment was performed including four substitution levels of DDGS (0, 250, 500 and 750 g/kg respectively) and two enzyme cocktail levels (0 and 250 mg/kg diet). The used enzyme in this study "Gallazyme" composed of xylanase, Trichoderma longibrachiatum (600 units/g), protease, Bacillus subtilis (8,000 units/g) and amylase and Bacillus amyloliquofaciens (800 units/g). The control diet showed the best feed efficiency followed by the intermediate levels of DDGS. The lowest value of feed efficiency was found in the group fed the highest level of DDGS. Enzyme addition improved feed efficiency and decreased laying rate. Increasing DDGS levels was associated with albumin and shell thickness increases. Dietary DDGS depressed all egg components except the organic matter which maximised in enzyme-treated groups. Increasing DDGS level was accompanied by increase in yolk cholesterol and total lipids. No significant impacts were detected with enzymes supplementation on yolk lipids profile. Excepting serum calcium and phosphorous, all serum constituents increased with increasing level of DDGS. Using enzyme markedly depressed serum ammonia by 15.02% and increased calcium by 6.44% compared with enzyme-free diets. Interaction between DDGS and enzyme was significant on most of studied parameters. It could be concluded that using enzyme cocktail in DDGS-based diets may improve feed efficiency and egg quality, in addition to lowering blood ammonia and increasing blood calcium. It is recommended to substitute SBM by DDGS up to 500 g/kg diet. © 2017 Blackwell Verlag GmbH.

Lesser scaup winter foraging and nutrient reserve acquisition in east-central Florida

USGS Publications Warehouse

Herring, G.; Collazo, J.A.

2006-01-01

Lesser scaup (Aythya affinis) populations have been declining since the late 1970s. One of the explanations to account for this decline, the spring-condition hypothesis (SCH), is based on the premise that scaup are limited by their ability to acquire or maintain nutrient reserves during migration to the breeding grounds, leading to an impairment of their reproductive potential. Available evidence suggests that endogenous reserves required for reproduction are obtained at a later stage of migration or after arrival at the breeding grounds, not wintering sites. However, only one study has addressed body-condition levels on a southern wintering site in the last decade, with results limited to the wintering grounds on the Mississippi Flyway. We documented foraging behavior, nutrient levels, and body mass of lesser scaup in east-central Florida, USA, where 62% of the Atlantic Flyway population overwinters, during the winters of 2002 and 2003. Diurnal foraging did not increase seasonally. Nocturnal foraging increased seasonally by 76% or 43 minutes per night in females and by 478% or 1.9 hours per night in males. Measures of body condition did not change seasonally during 2002 for either sex. Between early and later winter in 2003 corrected body mass (CBM) and lipid reserves of male scaup increased 77 g and 39 g, respectively. Our results suggest that lesser scaup maintain or may slightly improve their physiological condition in east-central Florida during winter. Lower body mass and differences in nutrient levels in east-central Florida, compared to a wintering site in Louisiana, likely stem from geographic variation and lower thermal requirements associated with the warmer Florida environment. Lesser scaup depart Florida with sufficient reserves to initiate spring migration, but they maximize nutrient reserves used during reproduction elsewhere during migration or on the breeding grounds. These results suggest that maintaining the ecological integrity of this wintering ground is critical in minimizing winter mortality and preventing it from becoming an ancillary factor in current declines. Future research should address understanding survival rates during spring migration and at critical staging areas to provide new insight into the ramifications of scaup leaving wintering habitats such as MINWR with lower body condition than at other wintering sites in other flyways.

Sirtuin-1 regulation of mammalian metabolism

PubMed Central

Gillum, Matthew P.; Erion, Derek M.; Shulman, Gerald I.

2011-01-01

Sirtuin-1 (SirT1) is a nutrient-sensing deacetylase whose levels and activity increase with caloric restriction to preserve euglycemia and promote efficient energy utilization. Focusing on data obtained in vivo, we review how SirT1 orchestrates the adaptive response to fasting by stimulating hepatic gluconeogenesis and fatty acid oxidation, increasing circulating adiponectin levels, and limiting immune activation. Finally, we consider its viability as a therapeutic target for the treatment of type 2 diabetes. PMID:20971038

Nutrient loading and consumers: Agents of change in open-coast macrophyte assemblages

PubMed Central

Nielsen, Karina J.

2003-01-01

Human activities are significantly altering nutrient regimes and the abundance of consumers in coastal ecosystems. A field experiment in an open-coast, upwelling ecosystem showed that small increases in nutrients increased the biomass and evenness of tide pool macrophytes where consumer abundance and nutrient loading rates were low. Consumers, when abundant, had negative effects on the diversity and biomass of macrophytes. Nutrient loading increases and consumers are less abundant and efficient as wave exposure increases along open coastlines. Experimentally reversing the natural state of nutrient supply and consumer pressure at a wave-protected site to match wave-exposed sites caused the structure of the macrophyte assemblage to converge on that found naturally in wave-exposed pools. The increases in evenness and abundance were driven by increases in structurally complex functional groups. In contrast, increased nutrient loading in semienclosed marine or estuarine ecosystems is typically associated with declines in macrophyte diversity because of increases in structurally simple and opportunistic functional groups. If nutrient concentration of upwelled waters changes with climatic warming or increasing frequency of El Niños, as predicted by some climate models, these results suggest that macrophyte abundance and evenness along wave-swept open-coasts will also change. Macrophytes represent a significant fraction of continental shelf production and provide important habitat for many marine species. The combined effects of shifting nutrient regimes and overexploitation of consumers may have unexpected consequences for the structure and functioning of open-coast communities. PMID:12796509

Nutrient loading and consumers: agents of change in open-coast macrophyte assemblages.

PubMed

Nielsen, Karina J

2003-06-24

Human activities are significantly altering nutrient regimes and the abundance of consumers in coastal ecosystems. A field experiment in an open-coast, upwelling ecosystem showed that small increases in nutrients increased the biomass and evenness of tide pool macrophytes where consumer abundance and nutrient loading rates were low. Consumers, when abundant, had negative effects on the diversity and biomass of macrophytes. Nutrient loading increases and consumers are less abundant and efficient as wave exposure increases along open coastlines. Experimentally reversing the natural state of nutrient supply and consumer pressure at a wave-protected site to match wave-exposed sites caused the structure of the macrophyte assemblage to converge on that found naturally in wave-exposed pools. The increases in evenness and abundance were driven by increases in structurally complex functional groups. In contrast, increased nutrient loading in semienclosed marine or estuarine ecosystems is typically associated with declines in macrophyte diversity because of increases in structurally simple and opportunistic functional groups. If nutrient concentration of upwelled waters changes with climatic warming or increasing frequency of El Niños, as predicted by some climate models, these results suggest that macrophyte abundance and evenness along wave-swept open-coasts will also change. Macrophytes represent a significant fraction of continental shelf production and provide important habitat for many marine species. The combined effects of shifting nutrient regimes and overexploitation of consumers may have unexpected consequences for the structure and functioning of open-coast communities.

High Levels of Dietary Supplement Vitamins A, C and E are Absorbed in the Small Intestine and Protect Nutrient Transport Against Chronic Gamma Irradiation.

PubMed

Roche, Marjolaine; Neti, Prasad V S V; Kemp, Francis W; Azzam, Edouard I; Ferraris, Ronaldo P; Howell, Roger W

2015-11-01

We examined nutrient transport in the intestines of mice exposed to chronic low-LET 137Cs gamma rays. The mice were whole-body irradiated for 3 days at dose rates of 0, 0.13 and 0.20 Gy/h, for total dose delivery of 0, 9.6 or 14.4 Gy, respectively. The mice were fed either a control diet or a diet supplemented with high levels of vitamins A, C and E. Our results showed that nutrient transport was perturbed by the chronic irradiation conditions. However, no apparent alteration of the macroscopic intestinal structures of the small intestine were observed up to day 10 after initiating irradiation. Jejunal fructose uptake measured in vitro was strongly affected by the chronic irradiation, whereas uptake of proline, carnosine and the bile acid taurocholate in the ileum was less affected. D-glucose transport did not appear to be inhibited significantly by either 9.6 or 14.4 Gy exposure. In the 14.4 Gy irradiated groups, the diet supplemented with high levels of vitamins A, C and E increased intestinal transport of fructose compared to the control diet (day 10; t test, P = 0.032), which correlated with elevated levels of vitamins A, C and E in the plasma and jejunal enterocytes. Our earlier studies with mice exposed acutely to 137Cs gamma rays demonstrated significant protection for transport of fructose, glucose, proline and carnosine. Taken together, these results suggest that high levels of vitamins A, C and E dietary supplements help preserve intestinal nutrient transport when intestines are irradiated chronically or acutely with low-LET gamma rays.

High Levels of Dietary Supplement Vitamins A, C and E are Absorbed in the Small Intestine and Protect Nutrient Transport Against Chronic Gamma Irradiation

PubMed Central

Azzam, Edouard I.; Ferraris, Ronaldo P.; Howell, Roger W.

2015-01-01

We examined nutrient transport in the intestines of mice exposed to chronic low-LET 137Cs gamma rays. The mice were whole-body irradiated for 3 days at dose rates of 0, 0.13 and 0.20 Gy/h, for total dose delivery of 0, 9.6 or 14.4 Gy, respectively. The mice were fed either a control diet or a diet supplemented with high levels of vitamins A, C and E. Our results showed that nutrient transport was perturbed by the chronic irradiation conditions. However, no apparent alteration of the macroscopic intestinal structures of the small intestine were observed up to day 10 after initiating irradiation. Jejunal fructose uptake measured in vitro was strongly affected by the chronic irradiation, whereas uptake of proline, carnosine and the bile acid taurocholate in the ileum was less affected. D-glucose transport did not appear to be inhibited significantly by either 9.6 or 14.4 Gy exposure. In the 14.4 Gy irradiated groups, the diet supplemented with high levels of vitamins A, C and E increased intestinal transport of fructose compared to the control diet (day 10; t test, P = 0.032), which correlated with elevated levels of vitamins A, C and E in the plasma and jejunal enterocytes. Our earlier studies with mice exposed acutely to 137Cs gamma rays demonstrated significant protection for transport of fructose, glucose, proline and carnosine. Taken together, these results suggest that high levels of vitamins A, C and E dietary supplements help preserve intestinal nutrient transport when intestines are irradiated chronically or acutely with low-LET gamma rays. PMID:26484399

Fish Consumption, Levels of Nutrients and Contaminants, and Endocrine-Related Health Outcomes Among Older Male Anglers in Wisconsin.

PubMed

Christensen, Krista Y; Raymond, Michelle R; Thompson, Brooke A; Anderson, Henry A

2016-07-01

The aim of this study was to examine associations between endocrine disorders, fish consumption habits, and biomarkers of contaminants and nutrients : Male anglers aged at least 50 years living in Wisconsin (n = 154) completed a questionnaire and provided biological samples. Adjusted logistic regression models were used to evaluate risk factors for endocrine outcomes. Nineteen percent of anglers reported either pre-diabetes or diabetes, while 4.6% reported thyroid disease. There were few associations between endocrine disease and fish consumption, fish meal source, or species, aside from a notable increase in diabetes risk with lake trout consumption. Docosahexaenoic acid, certain polychlorinated biphenyls (PCBs), and perfluorinated compounds were associated with an increased risk of diabetes or pre-diabetes. PCBs were associated with a decreased risk of thyroid disease. Fish consumption patterns may affect risk for endocrine outcomes, but direction and magnitude of association may depend on the balance of the contaminants and nutrients in the individual diet.

Application of a Three-Dimensional Water Quality Model as a Decision Support Tool for the Management of Land-Use Changes in the Catchment of an Oligotrophic Lake

NASA Astrophysics Data System (ADS)

Trolle, Dennis; Spigel, Bob; Hamilton, David P.; Norton, Ned; Sutherland, Donna; Plew, David; Allan, Mathew G.

2014-09-01

While expansion of agricultural land area and intensification of agricultural practices through irrigation and fertilizer use can bring many benefits to communities, intensifying land use also causes more contaminants, such as nutrients and pesticides, to enter rivers, lakes, and groundwater. For lakes such as Benmore in the Waitaki catchment, South Island, New Zealand, an area which is currently undergoing agricultural intensification, this could potentially lead to marked degradation of water clarity as well as effects on ecological, recreational, commercial, and tourism values. We undertook a modeling study to demonstrate science-based options for consideration of agricultural intensification in the catchment of Lake Benmore. Based on model simulations of a range of potential future nutrient loadings, it is clear that different areas within Lake Benmore may respond differently to increased nutrient loadings. A western arm (Ahuriri) could be most severely affected by land-use changes and associated increases in nutrient loadings. Lake-wide annual averages of an eutrophication indicator, the trophic level index (TLI) were derived from simulated chlorophyll a, total nitrogen, and total phosphorus concentrations. Results suggest that the lake will shift from oligotrophic (TLI = 2-3) to eutrophic (TLI = 4-5) as external loadings are increased eightfold over current baseline loads, corresponding to the potential land-use intensification in the catchment. This study provides a basis for use of model results in a decision-making process by outlining the environmental consequences of a series of land-use management options, and quantifying nutrient load limits needed to achieve defined trophic state objectives.

Water-quality assessment of Francis E Walter reservoir, Luzerne and Carbon counties, Pennsylvania

USGS Publications Warehouse

Barker, J.L.

1983-01-01

Water-quality data, both past and present, show that the waters of the upper Lehigh River basin are somewhat acidic, but otherwise are generally of good quality. This report contains a summary of all known water-quality data collected by the U.S. Geological Survey and other agencies, as well as a synopsis of current water-quality conditions in the reservoir and its tributaries. Water-quality data collected from June 1981 to May 1982 indicate that raising the pool level from 1,300 to approximately 1,392 feet above sea level (NGVD of 1929) has had some significant, if only temporary, detrimental impacts on the reservoir system and its discharge. Depth profile measurements show that, while the impoindment was thermally stratified for only about 2 weeks, the dissolved oxygen concentrations were depressed to levels critical to fishlife throughout much of the reservoir. Another effect of the raised pool was the lowering of pH in the impoinded water. Median pH values were less than 6.0 throughout the reservoir, whereas they commonly exceeded 6.5 at the normal pool elevation. Tests for fecal coliform and fecal streptococcus indicate the impoinded water is nearly free of enteric bacteria. Algal analyses and nutrient concentrations support the premise that the impoundment is nutrient poor and phosphorus limited. Raising the water level an additional 125 feet should have no permanent detrimental effect upon water quality and will greatly increase available habitat for fish and waterflow. Increased retention time should not alter the current trophic status and may decrease the concentration of available nutrients.

A Climate Change Adaptation Strategy for Management of Coastal Marsh Systems

EPA Science Inventory

Sea level rise is causing shoreline erosion, increased coastal flooding, and marsh vulnerability to the impact of storms. Coastal marshes provide flood abatement, carbon and nutrient sequestration, water quality maintenance, and habitat for fish, shellfish, and wildlife, includin...

The interactive effects of fire and diversity on short-term responses of ecosystem processes in experimental mediterranean grasslands.

PubMed

Dimitrakopoulos, Panayiotis G; Siamantziouras, Akis-Stavros D; Galanidis, Alexandros; Mprezetou, Irene; Troumbis, Andreas Y

2006-06-01

We conducted a field experiment using constructed communities to test whether species richness contributed to the maintenance of ecosystem processes under fire disturbance. We studied the effects of diversity components (i.e., species richness and species composition) upon productivity, structural traits of vegetation, decomposition rates, and soil nutrients between burnt and unburnt experimental Mediterranean grassland communities. Our results demonstrated that fire and species richness had interactive effects on aboveground biomass production and canopy structure components. Fire increased biomass production of the highest-richness communities. The effects of fire on aboveground biomass production at different levels of species richness were derived from changes in both vertical and horizontal canopy structure of the communities. The most species-rich communities appeared to be more resistant to fire in relation to species-poor ones, due to both compositional and richness effects. Interactive effects of fire and species richness were not important for belowground processes. Decomposition rates increased with species richness, related in part to increased levels of canopy structure traits. Fire increased soil nutrients and long-term decomposition rate. Our results provide evidence that composition within richness levels had often larger effects on the stability of aboveground ecosystem processes in the face of fire disturbance than species richness per se.

Bark analysis as a guide to cassava nutrition in Sierra Leone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Godfrey-Sam-Aggrey, W.; Garber, M.J.

1979-01-01

Cassava main stem barks from two experiments in which similar fertilizers were applied directly in a 2/sup 5/ confounded factorial design were analyzed and the bark nutrients used as a guide to cassava nutrition. The application of multiple regression analysis to the respective root yields and bark nutrient concentrations enable nutrient levels and optimum adjusted root yields to be derived. Differences in bark nutrient concentrations reflected soil fertility levels. Bark analysis and the application of multiple regression analysis to root yields and bark nutrients appear to be useful tools for predicting fertilizer recommendations for cassava production.

Highly Dynamic Cellular-Level Response of Symbiotic Coral to a Sudden Increase in Environmental Nitrogen

PubMed Central

Kopp, C.; Pernice, M.; Domart-Coulon, I.; Djediat, C.; Spangenberg, J. E.; Alexander, D. T. L.; Hignette, M.; Meziane, T.; Meibom, A.

2013-01-01

ABSTRACT Metabolic interactions with endosymbiotic photosynthetic dinoflagellate Symbiodinium spp. are fundamental to reef-building corals (Scleractinia) thriving in nutrient-poor tropical seas. Yet, detailed understanding at the single-cell level of nutrient assimilation, translocation, and utilization within this fundamental symbiosis is lacking. Using pulse-chase 15N labeling and quantitative ion microprobe isotopic imaging (NanoSIMS; nanoscale secondary-ion mass spectrometry), we visualized these dynamic processes in tissues of the symbiotic coral Pocillopora damicornis at the subcellular level. Assimilation of ammonium, nitrate, and aspartic acid resulted in rapid incorporation of nitrogen into uric acid crystals (after ~45 min), forming temporary N storage sites within the dinoflagellate endosymbionts. Subsequent intracellular remobilization of this metabolite was accompanied by translocation of nitrogenous compounds to the coral host, starting at ~6 h. Within the coral tissue, nitrogen is utilized in specific cellular compartments in all four epithelia, including mucus chambers, Golgi bodies, and vesicles in calicoblastic cells. Our study shows how nitrogen-limited symbiotic corals take advantage of sudden changes in nitrogen availability; this opens new perspectives for functional studies of nutrient storage and remobilization in microbial symbioses in changing reef environments. PMID:23674611

Combined effects between temporal heterogeneity of water supply, nutrient level, and population density on biomass of four broadly distributed herbaceous species.

PubMed

Hagiwara, Yousuke; Kachi, Naoki; Suzuki, Jun-Ichirou

2012-01-01

Temporal heterogeneity of water supply affects grassland community productivity and it can interact with nutrient level and intraspecific competition. To understand community responses, the responses of individual species to water heterogeneity must be evaluated while considering the interactions of this heterogeneity with nutrient levels and population density. We compared responses of four herbaceous species grown in monocultures to various combinations of water heterogeneity, nutrient level, and population density: two grasses (Cynodon dactylon and Lolium perenne), a forb (Artemisia princeps), and a legume (Trifolium repens). Treatment effects on shoot and root biomass were analyzed. In all four species, shoot biomass was larger under homogeneous than under heterogeneous water supply. Shoot responses of L. perenne tended to be greater at high nutrient levels. Although root biomass was also larger under homogeneous water supply, effects of water heterogeneity on root biomass were not significant in the grasses. Trifolium repens showed marked root responses, particularly at high population density. Although greater shoot and root growth under homogeneous water supply appears to be a general trend among herbaceous species, our results suggested differences among species could be found in the degree of response to water heterogeneity and its interactions with nutrient level and intraspecific competition.

What's Upstream? GIS's critical role in developing nutrient ...

EPA Pesticide Factsheets

Eutrophication due to excess levels of nitrogen and phosphorus can seriously impair ecological function in estuaries. Protective criteria for nutrients are difficult to establish because the source can vary spatially and seasonally, originate either from the watershed or the ocean, and be natural or anthropogenic. GIS tools and processes can help in developing nutrient criteria by establishing reference conditions representative of natural background nutrient levels. Along the Oregon Coast in the Pacific Northwest, the primary source of nutrients in the wet season (November-April) is generally riverine. We delineated and extracted explicit spatial data from watersheds upstream of riverine water quality monitoring stations for parametric comparison to recorded nutrient levels. The SPARROW model (Wise and Johnson, 2011) was used to estimate relative contributions of nutrient sources at each station. Both raster and vector spatial data were used and include land use / land cover, demography, geology, terrain, precipitation and forest type. The relationships of nutrients to spatial data were then explored as an approach to establishing the reference expectation. The abstract introduces Geographic Information Systems (GIS) tools and processes employed for research conducted under the Safe and Sustainable Water Resources (SSWR) Task 2.3A, entitled “Nutrient Management for Sustainability of Aquatic Ecosystems.” One of the goals of the EPA Office of Water is to

Effects of levan-type fructan on growth performance, nutrient digestibility, diarrhoea scores, faecal shedding of total lactic acid bacteria and coliform bacteria, and faecal gas emission in weaning pigs.

PubMed

Lei, Xin Jian; Kim, Yong Min; Park, Jae Hong; Baek, Dong Heon; Nyachoti, Charles Martin; Kim, In Ho

2018-03-01

The use of antibiotics as growth promoters in feed has been fully or partially banned in several countries. The objective of this study was to evaluate effects of levan-type fructan on growth performance, nutrient digestibility, faecal shedding of lactic acid bacteria and coliform bacteria, diarrhoea scores, and faecal gas emission in weaning pigs. A total of 144 weaning pigs [(Yorkshire × Landrace) × Duroc] were randomly allocated to four diets: corn-soybean meal-based diets supplemented with 0, 0.1, 0.5, or 1.0 g kg -1 levan-type fructan during this 42-day experiment. During days 0 to 21 and 0 to 42, average daily gain and average daily feed intake were linearly increased (P < 0.01) with increasing dietary levan-type fructan inclusion. The apparent total tract digestibility of dry matter, crude protein, and gross energy were linearly increased (P < 0.001) with increasing dietary levan-type fructan content. With increasing levels of levan-type fructan, faecal lactic acid bacteria counts were linearly increased (P = 0.001). The results indicate that dietary supplementation with increasing levan-type fructan enhanced growth performance, improved nutrient digestibility, and increased faecal lactic acid bacteria counts in weaning pigs linearly. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

High nutrient availability reduces the diversity and stability of the equine caecal microbiota

PubMed Central

Hansen, Naja C. K.; Avershina, Ekaterina; Mydland, Liv T.; Næsset, Jon A.; Austbø, Dag; Moen, Birgitte; Måge, Ingrid; Rudi, Knut

2015-01-01

Background It is well known that nutrient availability can alter the gut microbiota composition, while the effect on diversity and temporal stability remains largely unknown. Methods Here we address the equine caecal microbiota temporal stability, diversity, and functionality in response to diets with different levels of nutrient availability. Hay (low and slower nutrient availability) versus a mixture of hay and whole oats (high and more rapid nutrient availability) were used as experimental diets. Results We found major effects on the microbiota despite that the caecal pH was far from sub-clinical acidosis. We found that the low nutrient availability diet was associated with a higher level of both diversity and temporal stability of the caecal microbiota than the high nutrient availability diet. These observations concur with general ecological theories, suggesting a stabilising effect of biological diversity and that high nutrient availability has a destabilising effect through reduced diversity. Conclusion Nutrient availability does not only change the composition but also the ecology of the caecal microbiota. PMID:26246403

Nutrient enrichment is associated with altered nectar and pollen chemical composition in Succisa pratensis Moench and increased larval mortality of its pollinator Bombus terrestris L.

PubMed

Ceulemans, Tobias; Hulsmans, Eva; Vanden Ende, Wim; Honnay, Olivier

2017-01-01

Pollinators are declining worldwide and possible underlying causes include disease, invasive pest species and large scale land use changes resulting in habitat loss and degradation. One particular cause of habitat degradation is the increased inflow of nutrients due to anthropogenic combustion processes and large scale application of agricultural fertilizers. This nutrient pollution has been shown to affect pollinators through the loss of nectar and pollen-providing plant species. However, it may also affect pollinators through altering the nectar and pollen chemical composition of plant species, hence influencing pollinator food quality. Here, we experimentally investigated the effect of nutrient enrichment on amino acid and sugar composition of nectar and pollen in the grassland plant Sucissa pratensis, and the subsequent colony size and larval mortality of the pollinating bumblebee Bombus terrestris. We found less of the essential amino acids glycine and arginine in the pollen of fertilized plants, and more arginine, ornithine and threonine in the pollen of control plants. Nectar glucose and pollen fructose levels were lower in fertilized plants as compared to control plants. Furthermore, bumblebee colonies visiting fertilized plants showed more dead larvae than colonies visiting control plants. Our results suggest that the fitness of bumblebees can be negatively affected by changes in their food quality following nutrient pollution. If similar patterns hold for other plant and pollinator species, this may have far reaching implications for the maintenance of pollination ecosystem services, as nutrient pollution continues to rise worldwide.

Nutrient enrichment is associated with altered nectar and pollen chemical composition in Succisa pratensis Moench and increased larval mortality of its pollinator Bombus terrestris L.

PubMed Central

Vanden Ende, Wim; Honnay, Olivier

2017-01-01

Pollinators are declining worldwide and possible underlying causes include disease, invasive pest species and large scale land use changes resulting in habitat loss and degradation. One particular cause of habitat degradation is the increased inflow of nutrients due to anthropogenic combustion processes and large scale application of agricultural fertilizers. This nutrient pollution has been shown to affect pollinators through the loss of nectar and pollen-providing plant species. However, it may also affect pollinators through altering the nectar and pollen chemical composition of plant species, hence influencing pollinator food quality. Here, we experimentally investigated the effect of nutrient enrichment on amino acid and sugar composition of nectar and pollen in the grassland plant Sucissa pratensis, and the subsequent colony size and larval mortality of the pollinating bumblebee Bombus terrestris. We found less of the essential amino acids glycine and arginine in the pollen of fertilized plants, and more arginine, ornithine and threonine in the pollen of control plants. Nectar glucose and pollen fructose levels were lower in fertilized plants as compared to control plants. Furthermore, bumblebee colonies visiting fertilized plants showed more dead larvae than colonies visiting control plants. Our results suggest that the fitness of bumblebees can be negatively affected by changes in their food quality following nutrient pollution. If similar patterns hold for other plant and pollinator species, this may have far reaching implications for the maintenance of pollination ecosystem services, as nutrient pollution continues to rise worldwide. PMID:28406910

Nitrogen limitation of growth and nutrient dynamics in a disturbed mangrove forest, Indian River Lagoon, Florida

USGS Publications Warehouse

Feller, Ilka C.; Whigham, D.F.; McKee, K.L.; Lovelock, C.E.

2003-01-01

The objectives of this study were to determine effects of nutrient enrichment on plant growth, nutrient dynamics, and photosynthesis in a disturbed mangrove forest in an abandoned mosquito impoundment in Florida. Impounding altered the hydrology and soil chemistry of the site. In 1997, we established a factorial experiment along a tree-height gradient with three zones, i.e., fringe, transition, dwarf, and three fertilizer treatment levels, i.e., nitrogen (N), phosphorus (P), control, in Mosquito Impoundment 23 on the eastern side of Indian River. Transects traversed the forest perpendicular to the shoreline, from a Rhizophora mangle-dominated fringe through an Avicennia germinans stand of intermediate height, and into a scrub or dwarf stand of A. germinans in the hinterland. Growth rates increased significantly in response to N fertilization. Our growth data indicated that this site is N-limited along the tree-height gradient. After 2 years of N addition, dwarf trees resembled vigorously growing saplings. Addition of N also affected internal dynamics of N and P and caused increases in rates of photosynthesis. These findings contrast with results for a R. mangle-dominated forest in Belize where the fringe is N-limited, but the dwarf zone is P-limited and the transition zone is co-limited by N and P. This study demonstrated that patterns of nutrient limitation in mangrove ecosystems are complex, that not all processes respond similarly to the same nutrient, and that similar habitats are not limited by the same nutrient when different mangrove forests are compared.

Use of hydroponics culture to assess nutrient supply by treated wastewater.

PubMed

Adrover, Maria; Moyà, Gabriel; Vadell, Jaume

2013-09-30

The use of treated wastewater for irrigation is increasing, especially in those areas where water resources are limited. Treated wastewaters contain nutrients that are useful for plant growth and help to reduce fertilizers needs. Nutrient content of these waters depends on the treatment system. Nutrient supply by a treated wastewater from a conventional treatment plant (CWW) and a lagooned wastewater from the campus of the University of Balearic Islands (LWW) was tested in an experiment in hydroponics conditions. Half-strength Hoagland nutrient solution (HNS) was used as a control. Barley (Hordeum vulgare L.) seedlings were grown in 4 L containers filled with the three types of water. Four weeks after planting, barley was harvested and root and shoot biomass was measured. N, P, K, Ca, Mg, Na and Fe contents were determined in both tissues and heavy metal concentrations were analysed in shoots. N, P and K concentrations were lower in LWW than in CWW, while HNS had the highest nutrient concentration. Dry weight barley production was reduced in CWW and LWW treatments to 49% and 17%, respectively, comparing to HNS. However, to a lesser extent, reduction was found in shoot and root N content. Treated wastewater increased Na content in shoots and roots of barley and Ca and Cr content in shoots. However, heavy metals content was lower than toxic levels in all the cases. Although treated wastewater is an interesting water resource, additional fertilization is needed to maintain a high productivity in barley seedlings. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tide- and rainfall-induced variations of physical and chemical parameters in a mangrove-depleted estuary of East Hainan (South China Sea).

PubMed

Krumme, Uwe; Herbeck, Lucia S; Wang, Tianci

2012-12-01

The estuarine dynamics favoring the coexistence of mangroves, seagrass and corals at small river mouths are often poorly understood. We characterize the tidal, day/night and rainfall-induced short-term dynamics in salinity, pH, dissolved oxygen (DO), chlorophyll a (chl a), total suspended matter (TSM), water transparency, surface currents and dissolved nutrients (NO(x)(-), NH(4)(+), PO(4)(3)(-), Si(OH)(4)) of the Wenchang/Wenjiao Estuary (East Hainan, tropical China). Samples were taken at three fixed sites along the estuary during 24 h spring tide cycles in different seasons. Salinity, DO, water transparency and pH generally increased seawards while nutrients decreased. All parameters varied with the tidal cycle, partially in interaction with the diel cycle. Nutrients, chl a and TSM usually fluctuated inversely with water level. Stratification was strong. Inflowing bottom water was of higher salinity, DO and pH and lower temperature and nutrient concentrations than the surface water. Tidal mixing provided regular ventilation of the estuary and limited eutrophication effects of nutrients from aquaculture, agriculture and urban effluents. Under dry weather conditions, the brackish-water lagoon functioned as a sink of nutrients due to efficient uptake by phytoplankton. Presently, the runoff from common intense rains in the watershed affects the estuary with little time delay due to terrestrial deforestation, channelization and loss of mangrove area. The frequency, strength and duration of intermittent estuarization of the back-reef areas have likely increased in the past and deteriorate present seagrass and coral health. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhancing phosphorus and zinc acquisition efficiency in rice: a critical review of root traits and their potential utility in rice breeding.

PubMed

Rose, T J; Impa, S M; Rose, M T; Pariasca-Tanaka, J; Mori, A; Heuer, S; Johnson-Beebout, S E; Wissuwa, M

2013-07-01

Rice is the world's most important cereal crop and phosphorus (P) and zinc (Zn) deficiency are major constraints to its production. Where fertilizer is applied to overcome these nutritional constraints it comes at substantial cost to farmers and the efficiency of fertilizer use is low. Breeding crops that are efficient at acquiring P and Zn from native soil reserves or fertilizer sources has been advocated as a cost-effective solution, but would benefit from knowledge of genes and mechanisms that confer enhanced uptake of these nutrients by roots. This review discusses root traits that have been linked to P and Zn uptake in rice, including traits that increase mobilization of P/Zn from soils, increase the volume of soil explored by roots or root surface area to recapture solubilized nutrients, enhance the rate of P/Zn uptake across the root membrane, and whole-plant traits that affect root growth and nutrient capture. In particular, this review focuses on the potential for these traits to be exploited through breeding programmes to produce nutrient-efficient crop cultivars. Few root traits have so far been used successfully in plant breeding for enhanced P and Zn uptake in rice or any other crop. Insufficient genotypic variation for traits or the failure to enhance nutrient uptake under realistic field conditions are likely reasons for the limited success. More emphasis is needed on field studies in mapping populations or association panels to identify those traits and underlying genes that are able to enhance nutrient acquisition beyond the level already present in most cultivars.

Seasonal amounts of nutrients in Western cherry fruit fly (Diptera: Tephritidae) and their relation to nutrient availability on cherry plant surfaces.

PubMed

Yee, Wee L; Chapman, Peter S

2008-10-01

Relatively little is known about the nutritional ecology of fruit flies in the genus Rhagoletis. In this study, nutrient amounts in male and female western cherry fruit fly, Rhagoletis indifferens Curran, and availability of nitrogen and sugar on surfaces of leaves, fruit, and extrafloral nectaries (EFNs) of sweet cherry trees, were determined from late May to late June 2005 and of sugar from EFNs from mid-May to late June 2007 in Washington state. Protein amounts in male and female flies did not differ over the season. Nitrogen was present on leaves, fruit, and EFNs during the sampling period, but amounts on leaves and fruit were lower in late May than the rest of the season. Sugar amounts in flies did not differ over the season. Sugar was present on leaf, fruit, and EFN surfaces all season, but amounts on all three were lower in late May than later in the season. Fructose and glucose were the predominant sugars on all plant surfaces, but sucrose was also present in nectar from EFNs. In outdoor and field cage experiments in 2004 and 2006, more flies survived when cherry branches with leaves and fruit were present than absent. Results suggest that R. indifferens maintains stable protein and sugar levels throughout the season because sufficient amounts of nutrients are found in cherry trees during this time and that increases in nutrient availability caused by ripening and damaged cherries later in the season do not result in increased amounts of nutrients in flies.

Nitrogenase and Alkaline Phosphatase Activity in Wetland Metaphyton: Implications for Primary Production and CNP Composition

NASA Astrophysics Data System (ADS)

Scott, T.; Doyle, R.

2005-05-01

Longitudinal gradients of nutrient availability often occur along the flow path of water in freshwater wetlands. Differential removal efficiencies of water column nitrogen (N) and phosphorus (P) may increase the severity of nutrient deficiency and possibly change the nutrient that limits primary production. A previous study demonstrated that periphyton in the Lake Waco Wetlands (LWW), near Waco, Texas, USA, are generally more P limited near the inflow and become increasingly N limited as distance from the inflow increases. Therefore, spatial heterogeneity in nutrient availability likely influences both the structure and function of periphyton assemblages within this system. In this ongoing study, we are evaluating the relationships between metaphyton primary production, nitrogenase activity, alkaline phosphatase activity, and CNP stoichiometry in areas of differing nutrient limitation within the LWW. As expected, primary production is generally greatest in areas where nitrogenase and alkaline phosphatase activities are minimal. However, expected increases in C:N ratios in areas of greatest nutrient deficiency have not been frequently observed. Decreased primary production and increased enzyme mediated nutrient uptake appear to balance metaphyton nutrient content in these areas.

Local geology determines responses of stream producers and fungal decomposers to nutrient enrichment: A field experiment.

PubMed

Mykrä, Heikki; Sarremejane, Romain; Laamanen, Tiina; Karjalainen, Satu Maaria; Markkola, Annamari; Lehtinen, Sirkku; Lehosmaa, Kaisa; Muotka, Timo

2018-04-16

We examined how short-term (19 days) nutrient enrichment influences stream fungal and diatom communities, and rates of leaf decomposition and algal biomass accrual. We conducted a field experiment using slow-releasing nutrient pellets to increase nitrate (NO 3 -N) and phosphate (PO 4 -P) concentrations in a riffle section of six naturally acidic (naturally low pH due to catchment geology) and six circumneutral streams. Nutrient enrichment increased microbial decomposition rate on average by 14%, but the effect was significant only in naturally acidic streams. Nutrient enrichment also decreased richness and increased compositional variability of fungal communities in naturally acidic streams. Algal biomass increased in both stream types, but algal growth was overall very low. Diatom richness increased in response to nutrient addition by, but only in circumneutral streams. Our results suggest that primary producers and decomposers are differentially affected by nutrient enrichment and that their responses to excess nutrients are context dependent, with a potentially stronger response of detrital processes and fungal communities in naturally acidic streams than in less selective environments.

Wastewater and Sludge Nutrient Utilization in Forest Ecosystems

Treesearch

D.G. Brockway; D.H. Urie; P.V. Nguyen; J.B. Hart

1986-01-01

Although forest ecosystems have evolved efficient mechanisms to assimilate and retain modest levels of annual geochemical input, their productivity is frequently limited by low levels of available nutrients. A review of research studies conducted in the major U.S. forest regions indicates that the nutrients and organic matter in wastewater and sludge representa...

Loblolly pine growth and soil nutrient stocks eight years after forest slash incorporation

Treesearch

Felipe G. Sanchez; Emily A. Carter; Zakiya H. Leggett

2009-01-01

Incorporation of forest slash during stand establishment is proposed as a means of increasing soil carbon and nutrient stocks. If effective, the increased soil carbon and nutrient status may result in increased aboveground tree growth. Eight years after study installation, the impact of forest slash incorporation into the soil on soil carbon and nutrient stocks, foliar...

Competition for nutrients and light: testing advances in resource competition with a natural phytoplankton community.

PubMed

Burson, Amanda; Stomp, Maayke; Greenwell, Emma; Grosse, Julia; Huisman, Jef

2018-05-01

A key challenge in ecology is to understand how nutrients and light affect the biodiversity and community structure of phytoplankton and plant communities. According to resource competition models, ratios of limiting nutrients are major determinants of species composition. At high nutrient levels, however, species interactions may shift to competition for light, which might make nutrient ratios less relevant. The "nutrient-load hypothesis" merges these two perspectives, by extending the classic model of competition for two nutrients to include competition for light. Here, we test five key predictions of the nutrient-load hypothesis using multispecies competition experiments. A marine phytoplankton community sampled from the North Sea was inoculated in laboratory chemostats provided with different nitrogen (N) and phosphorus (P) loads to induce either single resource limitation or co-limitation of N, P, and light. Four of the five predictions were validated by the experiments. In particular, different resource limitations favored the dominance of different species. Increasing nutrient loads caused changes in phytoplankton species composition, even if the N:P ratio of the nutrient loads remained constant, by shifting the species interactions from competition for nutrients to competition for light. In all treatments, small species became dominant whereas larger species were competitively excluded, supporting the common view that small cell size provides a competitive advantage under resource-limited conditions. Contrary to expectation, all treatments led to coexistence of diatoms, cyanobacteria and green algae, resulting in a higher diversity of species than predicted by theory. Because the coexisting species comprised three phyla with different photosynthetic pigments, we speculate that niche differentiation in the light spectrum might play a role. Our results show that mechanistic resource competition models that integrate nutrient-based and light-based approaches provide an important step forward to understand and predict how changing nutrient loads affect community composition. © 2018 The Authors Ecology published by Wiley Periodicals, Inc. on behalf of Ecological Society of America.

Assessment of nutrient supplement to reduce gentamicin-induced ototoxicity.

PubMed

Le Prell, C G; Ojano-Dirain, C; Rudnick, E W; Nelson, M A; DeRemer, S J; Prieskorn, D M; Miller, J M

2014-06-01

Gentamicin is an aminoglycoside antibiotic used to treat gram-negative bacterial infections. Treatment with this antibiotic carries the potential for adverse side effects, including ototoxicity and nephrotoxicity. Ototoxic effects are at least in part a consequence of oxidative stress, and various antioxidants have been used to attenuate gentamicin-induced hair cell death and hearing loss. Here, a combination of nutrients previously shown to reduce oxidative stress in the hair cells and attenuate hearing loss after other insults was evaluated for potential protection against gentamicin-induced ototoxicity. Guinea pigs were maintained on a nutritionally complete standard laboratory animal diet or a diet supplemented with β-carotene, vitamins C and E, and magnesium. Three diets with iterative increases in nutrient levels were screened; the final diet selected for study use was one that produced statistically reliable increases in plasma levels of vitamins C and E and magnesium. In two separate studies, significant decreases in gentamicin-induced hearing loss at frequencies including 12 kHz and below were observed, with less benefit at the higher frequencies. Consistent with the functional protection, robust protection of both the inner and outer hair cell populations was observed, with protection largely in the upper half of the cochlea. Protection was independently assessed in two different laboratories, using two different strains of guinea pigs. Additional in vitro tests did not reveal any decrease in antimicrobial activity with nutrient additives. Currently, there are no FDA-approved treatments for the prevention of gentamicin-induced ototoxicity. The current data provide a rationale for continued investigations regarding translation to human patients.

Extent of pyrolysis impacts on fast pyrolysis biochar properties.

PubMed

Brewer, Catherine E; Hu, Yan-Yan; Schmidt-Rohr, Klaus; Loynachan, Thomas E; Laird, David A; Brown, Robert C

2012-01-01

A potential concern about the use of fast pyrolysis rather than slow pyrolysis biochars as soil amendments is that they may contain high levels of bioavailable C due to short particle residence times in the reactors, which could reduce the stability of biochar C and cause nutrient immobilization in soils. To investigate this concern, three corn ( L.) stover fast pyrolysis biochars prepared using different reactor conditions were chemically and physically characterized to determine their extent of pyrolysis. These biochars were also incubated in soil to assess their impact on soil CO emissions, nutrient availability, microorganism population growth, and water retention capacity. Elemental analysis and quantitative solid-state C nuclear magnetic resonance spectroscopy showed variation in O functional groups (associated primarily with carbohydrates) and aromatic C, which could be used to define extent of pyrolysis. A 24-wk incubation performed using a sandy soil amended with 0.5 wt% of corn stover biochar showed a small but significant decrease in soil CO emissions and a decrease in the bacteria:fungi ratios with extent of pyrolysis. Relative to the control soil, biochar-amended soils had small increases in CO emissions and extractable nutrients, but similar microorganism populations, extractable NO levels, and water retention capacities. Corn stover amendments, by contrast, significantly increased soil CO emissions and microbial populations, and reduced extractable NO. These results indicate that C in fast pyrolysis biochar is stable in soil environments and will not appreciably contribute to nutrient immobilization. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Elymus repens biomass allocation and acquisition as affected by light and nutrient supply and companion crop competition

PubMed Central

Ringselle, Björn; Prieto-Ruiz, Inés; Andersson, Lars; Aronsson, Helena; Bergkvist, Göran

2017-01-01

Background and Aims Competitive crops are a central component of resource-efficient weed control, especially for problematic perennial weeds such as Elymus repens. Competition not only reduces total weed biomass, but denial of resources can also change the allocation pattern – potentially away from the underground storage organs that make perennial weeds difficult to control. Thus, the competition mode of crops may be an important component in the design of resource-efficient cropping systems. Our aim was to determine how competition from companion crops with different modes of competition affect E. repens biomass acquisition and allocation and discuss that in relation to how E. repens responds to different levels of light and nutrient supply. Methods Greenhouse experiments were conducted with E. repens growing in interspecific competition with increasing density of perennial ryegrass or red clover, or growing at three levels of both light and nutrient supply. Key Results Elymus repens total biomass decreased with increasing biomass of the companion crop and the rate of decrease was higher with red clover than with perennial ryegrass, particularly for E. repens rhizome biomass. A reduced nutrient supply shifted E. repens allocation towards below-ground biomass while a reduced light supply shifted it towards shoot biomass. Red clover caused no change in E. repens allocation pattern, while ryegrass mostly shifted the allocation towards below-ground biomass, but the change was not correlated with ryegrass biomass. Conclusions The companion crop mode of competition influences both the suppression rate of E. repens biomass acquisition and the likelihood of shifts in E. repens biomass allocation. PMID:28025285

Engineering crop nutrient efficiency for sustainable agriculture.

PubMed

Chen, Liyu; Liao, Hong

2017-10-01

Increasing crop yields can provide food, animal feed, bioenergy feedstocks and biomaterials to meet increasing global demand; however, the methods used to increase yield can negatively affect sustainability. For example, application of excess fertilizer can generate and maintain high yields but also increases input costs and contributes to environmental damage through eutrophication, soil acidification and air pollution. Improving crop nutrient efficiency can improve agricultural sustainability by increasing yield while decreasing input costs and harmful environmental effects. Here, we review the mechanisms of nutrient efficiency (primarily for nitrogen, phosphorus, potassium and iron) and breeding strategies for improving this trait, along with the role of regulation of gene expression in enhancing crop nutrient efficiency to increase yields. We focus on the importance of root system architecture to improve nutrient acquisition efficiency, as well as the contributions of mineral translocation, remobilization and metabolic efficiency to nutrient utilization efficiency. © 2017 Institute of Botany, Chinese Academy of Sciences.

Soil nutrient bioavailability and nutrient content of pine trees (Pinus thunbergii) in areas impacted by acid deposition in Korea.

PubMed

Yang, Jae E; Lee, Wi-Young; Ok, Yong Sik; Skousen, Jeffrey

2009-10-01

Acid deposition has caused detrimental effects on tree growth near industrial areas of the world. Preliminary work has indicated that concentrations of NO(3-), SO(4)(2-), F( - ) and Al in soil solutions were 2 to 33 times higher in industrial areas compared to non-industrial areas in Korea. This study evaluated soil nutrient bioavailability and nutrient contents of red pine (Pinus thunbergii) needles in forest soils of industrial and non-industrial areas of Korea. Results confirm that forest soils of industrial areas have been acidified mainly by deposition of sulfate, resulting in increases of Al, Fe and Mn and decreases of Ca, Mg and K concentrations in soils and soil solutions. In soils of industrial areas, the molar ratios of Ca/Al and Mg/Al in forest soils were <2, which can lead to lower levels and availability of nutrients for tree growth. The Ca/Al molar ratio of Pinus thunbergii needles on non-industrial sites was 15, while that of industrial areas was 10. Magnesium concentrations in needles of Pinus thunbergii were lower in soils of industrial areas and the high levels of acid cations such as Al and Mn in these soils may have antagonized the uptake of base cations like Mg. Continued acidification can further reduce uptake of base cations by trees. Results show that Mg deficiency and high concentrations of Al and Mn in soil solution can be limiting factors for Pinus thunbergii growth in industrial areas of Korea.

Mathematical Model of the Role of RdCVF in the Coexistence of Rods and Cones in a Healthy Eye.

PubMed

Camacho, Erika T; Léveillard, Thierry; Sahel, José-Alain; Wirkus, Stephen

2016-07-01

Understanding the essential components and processes for coexistence of rods and cones is at the forefront of retinal research. The recent discovery on RdCVF's mechanism and mode of action for enhancing cone survival brings us a step closer to unraveling key questions of coexistence and codependence of these neurons. In this work, we build from ecological and enzyme kinetic work on functional response kinetics and present a mathematical model that allows us to investigate the role of RdCVF and its contribution to glucose intake. Our model results and analysis predict a dual role of RdCVF for enhancing and repressing the healthy coexistence of the rods and cones. Our results show that maintaining RdCVF above a threshold value allows for coexistence. However, a significant increase above this value threatens the existence of rods as the cones become extremely efficient at uptaking glucose and begin to take most of it for themselves. We investigate the role of natural glucose intake and that due to RdCVF in both high and low nutrient levels. Our analysis reveals that under low nutrient levels coexistence is not possible regardless of the amount of RdCVF present. With high nutrient levels coexistence can be achieved with a relative small increase in glucose uptake. By understanding the contributions of rods to cones survival via RdCVF in a non-diseased retina, we hope to shed light on degenerative diseases such as retinitis pigmentosa.

Biosynthetic burden and plasmid burden limit expression of chromosomally integrated heterologous genes (pdc, adhB) in Escherichia coli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez, A.; York, S.W.; Yomano, L.P.

1999-10-01

Previous studies have shown an unexpectedly high nutrient requirement for efficient ethanol production by ethanologenic recombinants of Escherichia coli B such as LY01 which contain chromosomally integrated Zymomonas mobilis genes (pdc, adhB) encoding the ethanol pathway. The basis for this requirement has been identified as a media-dependent effect on the expression of the Z. mobilis genes rather than a nutritional limitation. Ethanol production was substantially increased without additional nutrients simply by increasing the level of pyruvate decarboxylase activity. This was accomplished by adding a multicopy plasmid containing pdc alone (but not adhB alone) to strain LY01, and by adding multicopymore » plasmids which express pdc and adhB from strong promoters. New strong promoters were isolated from random fragments of Z. mobilis DNA and characterized but were not used to construct integrated biocatalysts. These promoters contained regions resembling recognition sites for 3 different E. coli sigma factors: {sigma}{sup 70}, {sigma}{sup 38}, and {sigma}{sup 28}. The most effective plasmid-based promoters for fermentation were recognized by multiple sigma factors, expressed both pdc and adhB at high levels, and produced ethanol efficiently while allowing up to 80% reduction in complex nutrients as compared to LY01. The ability to utilize multiple sigma factors may be advantageous to maintain the high levels of PDC and ADH needed for efficient ethanol production throughout batch fermentation.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivas-Ubach, A.; Sardans, J.; Hódar, J. A.

Plants respond locally and systemically to herbivore attack. Most of the research conducted on plant-herbivore relationships at elemental and molecular levels have focused on nutrients or/and certain molecular compounds or specific families of defensive metabolites showing that herbivores tend to select plant individuals or species with higher nutrient concentrations and to avoid those with higher levels of phenolics and terpenes. Unfortunately, the defensive role of phenolics in conifers is still unclear. We performed stoichiometric and metabolomics, local and systemic, analyses in two subspecies of Pinus sylvestris under the herbivorous attack by the caterpillars of the pine processionary moth, an importantmore » pest in the Mediterranean Basin. Herbivorous attack was not associated with any of the elements analyzed. Both pine subspecies responded locally to folivory mainly by increasing the concentrations of various terpenes and phenolics. Systemic responses differed between subspecies and most of the metabolites presented intermediate concentrations between those of the affected parts and unattacked trees. Contrary as usually thought, foliar nutrient concentrations did not show to be a main factor of an alleged plant selection by adult female processionary moths for oviposition. Local increases in phenolics were more associated with antioxidant function for protection against oxidative damage produced by folivory. On the other hand, terpenes were directly related to defense against herbivores. Herbivory attack produced a general systemic shift in pines, including both primary and secondary metabolisms, that was, however, less intense and chemically different from the local responses. Subspecies responded similarly locally but differently to folivory at systemic level.« less

Nutrient density: addressing the challenge of obesity.

PubMed

Drewnowski, Adam

2017-10-30

Obesity rates are increasing worldwide. Potential reasons include excessive consumption of sugary beverages and energy-dense foods instead of more nutrient-rich options. On a per kJ basis, energy-dense grains, added sugars and fats cost less, whereas lean meats, seafood, leafy greens and whole fruit generally cost more. Given that consumer food choices are often driven by price, the observed social inequities in diet quality and health can be explained, in part, by nutrition economics. Achieving a nutrient-rich diet at an affordable cost has become progressively more difficult within the constraints of global food supply. However, given the necessary metrics and educational tools, it may be possible to eat better for less. New metrics of nutrient density help consumers identify foods, processed and unprocessed, that are nutrient-rich, affordable and appealing. Affordability metrics, created by adding food prices to food composition data, permit calculations of both kJ and nutrients per penny, allowing for new studies on the economic drivers of food choice. Merging dietary intake data with local or national food prices permits the estimation of individual-level diet costs. New metrics of nutrient balance can help identify those food patterns that provide optimal nutritional value. Behavioural factors, including cooking at home, have been associated with nutrition resilience, defined as healthier diets at lower cost. Studies of the energy and nutrient costs of the global food supply and diverse food patterns will permit a better understanding of the socioeconomic determinants of health. Dietary advice ought to be accompanied by economic feasibility studies.

Pheromonal regulation of starvation resistance in honey bee workers ( Apis mellifera)

NASA Astrophysics Data System (ADS)

Fischer, Patrick; Grozinger, Christina M.

2008-08-01

Most animals can modulate nutrient storage pathways according to changing environmental conditions, but in honey bees nutrient storage is also modulated according to changing behavioral tasks within a colony. Specifically, bees involved in brood care (nurses) have higher lipid stores in their abdominal fat bodies than forager bees. Pheromone communication plays an important role in regulating honey bee behavior and physiology. In particular, queen mandibular pheromone (QMP) slows the transition from nursing to foraging. We tested the effects of QMP exposure on starvation resistance, lipid storage, and gene expression in the fat bodies of worker bees. We found that indeed QMP-treated bees survived much longer compared to control bees when starved and also had higher lipid levels. Expression of vitellogenin RNA, which encodes a yolk protein that is found at higher levels in nurses than foragers, was also higher in the fat bodies of QMP-treated bees. No differences were observed in expression of genes involved in insulin signaling pathways, which are associated with nutrient storage and metabolism in a variety of species; thus, other mechanisms may be involved in increasing the lipid stores. These studies demonstrate that pheromone exposure can modify nutrient storage pathways and fat body gene expression in honey bees and suggest that chemical communication and social interactions play an important role in altering metabolic pathways.

SIRT3 Deacetylates ATP Synthase F1 Complex Proteins in Response to Nutrient- and Exercise-Induced Stress

PubMed Central

Vassilopoulos, Athanassios; Pennington, J. Daniel; Andresson, Thorkell; Rees, David M.; Bosley, Allen D.; Fearnley, Ian M.; Ham, Amy; Flynn, Charles Robb; Hill, Salisha; Rose, Kristie Lindsey; Kim, Hyun-Seok; Walker, John E.

2014-01-01

Abstract Aims: Adenosine triphosphate (ATP) synthase uses chemiosmotic energy across the inner mitochondrial membrane to convert adenosine diphosphate and orthophosphate into ATP, whereas genetic deletion of Sirt3 decreases mitochondrial ATP levels. Here, we investigate the mechanistic connection between SIRT3 and energy homeostasis. Results: By using both in vitro and in vivo experiments, we demonstrate that ATP synthase F1 proteins alpha, beta, gamma, and Oligomycin sensitivity-conferring protein (OSCP) contain SIRT3-specific reversible acetyl-lysines that are evolutionarily conserved and bind to SIRT3. OSCP was further investigated and lysine 139 is a nutrient-sensitive SIRT3-dependent deacetylation target. Site directed mutants demonstrate that OSCPK139 directs, at least in part, mitochondrial ATP production and mice lacking Sirt3 exhibit decreased ATP muscle levels, increased ATP synthase protein acetylation, and an exercise-induced stress-deficient phenotype. Innovation: This work connects the aging and nutrient response, via SIRT3 direction of the mitochondrial acetylome, to the regulation of mitochondrial energy homeostasis under nutrient-stress conditions by deacetylating ATP synthase proteins. Conclusion: Our data suggest that acetylome signaling contributes to mitochondrial energy homeostasis by SIRT3-mediated deacetylation of ATP synthase proteins. Antioxid. Redox Signal. 21, 551–564. PMID:24252090

Enhancing nutrition with pulses: defining a recommended serving size for adults

PubMed Central

Marinangeli, Christopher P F; Curran, Julianne; Barr, Susan I; Slavin, Joanne; Puri, Seema; Swaminathan, Sumathi; Tapsell, Linda; Patterson, Carol Ann

2017-01-01

Abstract Pulses, defined as dry-harvested leguminous crops, include several varieties of beans, peas, lentils, and chickpeas. There is no consensus around a recommended serving size of pulses within a balanced diet, which prevents the development of transregional strategies that rely on consistent messaging to drive increases in consumption. The purpose of this review is to define and disseminate an appropriate target for a minimum serving size of pulses on any given day that can be used in international or collaborative strategies to promote the consumption of pulses. Relevant data were reviewed to examine dietary guidelines across jurisdictions, determine consumption levels of pulses across the globe, evaluate the nutritional composition of pulses in the context of dietary nutrient insufficiency, and assess the impact of pulses on dietary quality. Across a variety of pulses, 100 g of cooked pulses aligned with most regional serving sizes for pulses and provides significant levels of nutrients that are underconsumed by specific age-sex groups. Moreover, 100 g of pulses provides a number of nutrients that qualify for nutrient content claims under regional regulatory frameworks. The data demonstrate that 100 g or 125 mL (0.5 metric cup) of cooked pulses is a reasonable target for aligning strategies that promote the dietary and nutritional attributes of these legumes. PMID:29202192

Choline: Clinical Nutrigenetic/Nutrigenomic Approaches for Identification of Functions and Dietary Requirements

PubMed Central

Zeisel, Steven H.

2013-01-01

Nutrigenetics/nutrigenomics (the study of the bidirectional interactions between genes and diet) is a rapidly developing field that is changing research and practice in human nutrition. Though eventually nutrition clinicians may be able to provide personalized nutrition recommendations, in the immediate future they are most likely to use this knowledge to improve dietary recommendations for populations. Currently, estimated average requirements are used to set dietary reference intakes because scientists cannot adequately identify subsets of the population that differ in requirement for a nutrient. Recommended intake levels must exceed the actual required intake for most of the population in order to assure that individuals with the highest requirement ingest adequate amounts of the nutrient. As a result, dietary reference intake levels often are set so high that diet guidelines suggest almost unattainable intakes of some foods. Once it is possible to identify common subgroups that differ in nutrient requirements using nutrigenetic/nutrigenomic profiling, targeted interventions and recommendations can be refined. In addition, when a large variance exists in response to a nutrient, statistical analyses often argue for a null effect. If responders could be differentiated from nonre-sponders based on nutrigenetic/nutrigenomic profiling, this statistical noise could be eliminated and the sensitivity of nutrition research greatly increased. PMID:20436254

Aquatic vegetation in response to increased eutrophication and degraded light climate in Eastern Lake Taihu: Implications for lake ecological restoration.

PubMed

Zhang, Yunlin; Liu, Xiaohan; Qin, Boqiang; Shi, Kun; Deng, Jianming; Zhou, Yongqiang

2016-04-04

Terrestrial and aquatic ecosystem degradation is widely recognized as a major global environmental and development problem. Although great efforts have been made to prevent aquatic ecosystem degradation, the degree, extent and impacts of this phenomenon remain controversial and unclear, such as its driving mechanisms. Here, we present results from a 17-year field investigation (1998-2014) of water quality and a 12-year remote sensing mapping (2003-2014) of the aquatic vegetation presence frequency (VPF) in Eastern Lake Taihu, a macrophyte-dominated bay of Lake Taihu in China. In the past 17 years, nutrient concentrations and water level (WL) have significantly increased, but the Secchi disk depth (SDD) has significantly decreased. These changes were associated with increased lake eutrophication and a degraded underwater light climate that further inhibited the growth of aquatic vegetation. In Eastern Lake Taihu, increased nutrients, chlorophyll a and WL, and a decreased SDD were all significantly correlated with a decreased VPF. NH4(+)-N concentration and SDD/WL were the most important controlling factors for VPF. Therefore, increased anthropogenic nutrient inputs and a degraded underwater light climate surely result in a decreased VPF. These results elucidate the driving mechanism of aquatic vegetation degradation and will facilitate Lake Taihu ecological restoration.

Aquatic vegetation in response to increased eutrophication and degraded light climate in Eastern Lake Taihu: Implications for lake ecological restoration

NASA Astrophysics Data System (ADS)

Zhang, Yunlin; Liu, Xiaohan; Qin, Boqiang; Shi, Kun; Deng, Jianming; Zhou, Yongqiang

2016-04-01

Terrestrial and aquatic ecosystem degradation is widely recognized as a major global environmental and development problem. Although great efforts have been made to prevent aquatic ecosystem degradation, the degree, extent and impacts of this phenomenon remain controversial and unclear, such as its driving mechanisms. Here, we present results from a 17-year field investigation (1998-2014) of water quality and a 12-year remote sensing mapping (2003-2014) of the aquatic vegetation presence frequency (VPF) in Eastern Lake Taihu, a macrophyte-dominated bay of Lake Taihu in China. In the past 17 years, nutrient concentrations and water level (WL) have significantly increased, but the Secchi disk depth (SDD) has significantly decreased. These changes were associated with increased lake eutrophication and a degraded underwater light climate that further inhibited the growth of aquatic vegetation. In Eastern Lake Taihu, increased nutrients, chlorophyll a and WL, and a decreased SDD were all significantly correlated with a decreased VPF. NH4+-N concentration and SDD/WL were the most important controlling factors for VPF. Therefore, increased anthropogenic nutrient inputs and a degraded underwater light climate surely result in a decreased VPF. These results elucidate the driving mechanism of aquatic vegetation degradation and will facilitate Lake Taihu ecological restoration.

A Forest Tent Caterpillar Outbreak Increased Resource Levels and Seedling Growth in a Northern Hardwood Forest.

PubMed

Rozendaal, Danaë M A; Kobe, Richard K

2016-01-01

In closed-canopy forests, gap formation and closure are thought to be major drivers of forest dynamics. Crown defoliation by insects, however, may also influence understory resource levels and thus forest dynamics. We evaluate the effect of a forest tent caterpillar outbreak on understory light availability, soil nutrient levels and tree seedling height growth in six sites with contrasting levels of canopy defoliation in a hardwood forest in northern lower Michigan. We compared resource levels and seedling growth of six hardwood species before, during and in the three years after the outbreak (2008-2012). Canopy openness increased strongly during the forest tent caterpillar outbreak in the four moderately and severely defoliated sites, but not in lightly defoliated sites. Total inorganic soil nitrogen concentrations increased in response to the outbreak in moderately and severely defoliated sites. The increase in total inorganic soil nitrogen was driven by a strong increase in soil nitrate, and tended to become stronger with increasing site defoliation. Seedling height growth increased for all species in the moderately and severely defoliated sites, but not in lightly defoliated sites, either during the outbreak year or in the year after the outbreak. Growth increases did not become stronger with increasing site defoliation, but were strongest in a moderately defoliated site with high soil nutrient levels. Growth increases tended to be strongest for the shade intolerant species Fraxinus americana and Prunus serotina, and the shade tolerant species Ostrya virginiana. The strong growth response of F. americana and P. serotina suggests that recurring forest tent caterpillar outbreaks may facilitate the persistence of shade intolerant species in the understory in the absence of canopy gaps. Overall, our results suggest that recurrent canopy defoliation resulting from cyclical forest insect outbreaks may be an additional driver of dynamics in temperate closed-canopy forests.

A Forest Tent Caterpillar Outbreak Increased Resource Levels and Seedling Growth in a Northern Hardwood Forest

PubMed Central

Rozendaal, Danaë M. A.; Kobe, Richard K.

2016-01-01

In closed-canopy forests, gap formation and closure are thought to be major drivers of forest dynamics. Crown defoliation by insects, however, may also influence understory resource levels and thus forest dynamics. We evaluate the effect of a forest tent caterpillar outbreak on understory light availability, soil nutrient levels and tree seedling height growth in six sites with contrasting levels of canopy defoliation in a hardwood forest in northern lower Michigan. We compared resource levels and seedling growth of six hardwood species before, during and in the three years after the outbreak (2008–2012). Canopy openness increased strongly during the forest tent caterpillar outbreak in the four moderately and severely defoliated sites, but not in lightly defoliated sites. Total inorganic soil nitrogen concentrations increased in response to the outbreak in moderately and severely defoliated sites. The increase in total inorganic soil nitrogen was driven by a strong increase in soil nitrate, and tended to become stronger with increasing site defoliation. Seedling height growth increased for all species in the moderately and severely defoliated sites, but not in lightly defoliated sites, either during the outbreak year or in the year after the outbreak. Growth increases did not become stronger with increasing site defoliation, but were strongest in a moderately defoliated site with high soil nutrient levels. Growth increases tended to be strongest for the shade intolerant species Fraxinus americana and Prunus serotina, and the shade tolerant species Ostrya virginiana. The strong growth response of F. americana and P. serotina suggests that recurring forest tent caterpillar outbreaks may facilitate the persistence of shade intolerant species in the understory in the absence of canopy gaps. Overall, our results suggest that recurrent canopy defoliation resulting from cyclical forest insect outbreaks may be an additional driver of dynamics in temperate closed-canopy forests. PMID:27870897

Effects of nutrient profiling and price changes based on NuVal® scores on food purchasing in an online experimental supermarket.

PubMed

Epstein, Leonard H; Finkelstein, Eric A; Katz, David L; Jankowiak, Noelle; Pudlewski, Corrin; Paluch, Rocco A

2016-08-01

The goal of the present study was to apply experimental economic methods in an online supermarket to examine the effects of nutrient profiling, and differential pricing based on the nutrient profile, on the overall diet quality, energy and macronutrients of the foods purchased, and diet cost. Participants were provided nutrient profiling scores or price adjustments based on nutrient profile scores while completing a hypothetical grocery shopping task. Prices of foods in the top 20 % of nutrient profiling scores were reduced (subsidized) by 25 % while those in the bottom 20 % of scores were increased (taxed) by 25 %. We evaluated the independent and interactive effects of nutrient profiling or price adjustments on overall diet quality of foods purchased as assessed by the NuVal® score, energy and macronutrients purchased and diet cost in a 2×2 factorial design. A large (>10 000 food items) online experimental supermarket in the USA. Seven hundred and eighty-one women. Providing nutrient profiling scores improved overall diet quality of foods purchased. Price changes were associated with an increase in protein purchased, an increase in energy cost, and reduced carbohydrate and protein costs. Price changes and nutrient profiling combined were associated with no unique benefits beyond price changes or nutrient profiling alone. Providing nutrient profile score increased overall NuVal® score without a reduction in energy purchased. Combining nutrient profiling and price changes did not show an overall benefit to diet quality and may be less useful than nutrient profiling alone to consumers who want to increase overall diet quality of foods purchased.

Metabolic regulation of cellular plasticity in the pancreas.

PubMed

Ninov, Nikolay; Hesselson, Daniel; Gut, Philipp; Zhou, Amy; Fidelin, Kevin; Stainier, Didier Y R

2013-07-08

Obese individuals exhibit an increase in pancreatic β cell mass; conversely, scarce nutrition during pregnancy has been linked to β cell insufficiency in the offspring [reviewed in 1, 2]. These phenomena are thought to be mediated mainly through effects on β cell proliferation, given that a nutrient-sensitive β cell progenitor population in the pancreas has not been identified. Here, we employed the fluorescent ubiquitination-based cell-cycle indicator system to investigate β cell replication in real time and found that high nutrient concentrations induce rapid β cell proliferation. Importantly, we found that high nutrient concentrations also stimulate β cell differentiation from progenitors in the intrapancreatic duct (IPD). Furthermore, using a new zebrafish line where β cells are constitutively ablated, we show that β cell loss and high nutrient intake synergistically activate these progenitors. At the cellular level, this activation process causes ductal cell reorganization as it stimulates their proliferation and differentiation. Notably, we link the nutrient-dependent activation of these progenitors to a downregulation of Notch signaling specifically within the IPD. Furthermore, we show that the nutrient sensor mechanistic target of rapamycin (mTOR) is required for endocrine differentiation from the IPD under physiological conditions as well as in the diabetic state. Thus, this study reveals critical insights into how cells modulate their plasticity in response to metabolic cues and identifies nutrient-sensitive progenitors in the mature pancreas. Copyright © 2013 Elsevier Ltd. All rights reserved.

Imbalanced Hemolymph Lipid Levels Affect Feeding Motivation in the Two-Spotted Cricket, Gryllus bimaculatus.

PubMed

Konuma, Takahiro; Tsukamoto, Yusuke; Nagasawa, Hiromichi; Nagata, Shinji

2016-01-01

Insect feeding behavior is regulated by many intrinsic factors, including hemolymph nutrient levels. Adipokinetic hormone (AKH) is a peptide factor that modulates hemolymph nutrient levels and regulates the nutritional state of insects by triggering the transfer of lipids into the hemolymph. We recently demonstrated that RNA interference (RNAi)-mediated knockdown of the AKH receptor (AKHR) reduces hemolymph lipid levels, causing an increase in the feeding frequency of the two-spotted cricket, Gryllus bimaculatus. This result indicated that reduced hemolymph lipid levels might motivate crickets to feed. In the present study, to elucidate whether hemolymph lipid levels contribute to insect feeding behavior, we attempted to manipulate hemolymph lipid levels via the lipophorin (Lp)-mediated lipid transferring system in G. bimaculatus. Of the constituent proteins in Lp, we focused on apolipophorin-III (GrybiApoLp-III) because of its possible role in facilitating lipid mobilization. First, we used RNAi to reduce the expression of GrybiApoLp-III. RNAi-mediated knockdown of GrybiApoLp-III had little effect on basal hemolymph lipid levels and the amount of food intake. In addition, hemolymph lipid levels remained static even after injecting AKH into GrybiApoLp-IIIRNAi crickets. These observations indicated that ApoLp-III does not maintain basal hemolymph lipid levels in crickets fed ad libitum, but is necessary for mobilizing lipid transfer into the hemolymph following AKH stimulation. Second, Lp (containing lipids) was injected into the hemolymph to induce a temporary increase in hemolymph lipid levels. Consequently, the initiation of feeding was delayed in a dose-dependent manner, indicating that increased hemolymph lipid levels reduced the motivation to feed. Taken together, these data validate the importance of basal hemolymph lipid levels in the control of energy homeostasis and for regulating feeding behavior in crickets.

Imbalanced Hemolymph Lipid Levels Affect Feeding Motivation in the Two-Spotted Cricket, Gryllus bimaculatus

PubMed Central

Konuma, Takahiro; Tsukamoto, Yusuke; Nagasawa, Hiromichi; Nagata, Shinji

2016-01-01

Insect feeding behavior is regulated by many intrinsic factors, including hemolymph nutrient levels. Adipokinetic hormone (AKH) is a peptide factor that modulates hemolymph nutrient levels and regulates the nutritional state of insects by triggering the transfer of lipids into the hemolymph. We recently demonstrated that RNA interference (RNAi)-mediated knockdown of the AKH receptor (AKHR) reduces hemolymph lipid levels, causing an increase in the feeding frequency of the two-spotted cricket, Gryllus bimaculatus. This result indicated that reduced hemolymph lipid levels might motivate crickets to feed. In the present study, to elucidate whether hemolymph lipid levels contribute to insect feeding behavior, we attempted to manipulate hemolymph lipid levels via the lipophorin (Lp)-mediated lipid transferring system in G. bimaculatus. Of the constituent proteins in Lp, we focused on apolipophorin-III (GrybiApoLp-III) because of its possible role in facilitating lipid mobilization. First, we used RNAi to reduce the expression of GrybiApoLp-III. RNAi-mediated knockdown of GrybiApoLp-III had little effect on basal hemolymph lipid levels and the amount of food intake. In addition, hemolymph lipid levels remained static even after injecting AKH into GrybiApoLp-IIIRNAi crickets. These observations indicated that ApoLp-III does not maintain basal hemolymph lipid levels in crickets fed ad libitum, but is necessary for mobilizing lipid transfer into the hemolymph following AKH stimulation. Second, Lp (containing lipids) was injected into the hemolymph to induce a temporary increase in hemolymph lipid levels. Consequently, the initiation of feeding was delayed in a dose-dependent manner, indicating that increased hemolymph lipid levels reduced the motivation to feed. Taken together, these data validate the importance of basal hemolymph lipid levels in the control of energy homeostasis and for regulating feeding behavior in crickets. PMID:27144650

Influence of granite-grit on nutrient digestibility and haematological parameters of broiler chickens fed rice offal based diets.

PubMed

Idachaba, C U; Abeke, F O; Olugbemi, T S; Ademu, L A

2013-10-01

A total of 270 broiler chickens were used for the study. The birds were fed common diet containing 23% Crude protein and 2864 kcal kg(-1) Metabolizable energy at the starter phase while 20% Crude protein and 2923 kcal kg(-1) Metabolizable energy was fed at the finisher phase. Starter and finisher diets contained 10 and 15% inclusion levels of rice offal respectively. Granite grit was added to the basal diet at 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0 g per bird per month thus making a total of six treatments. Each treatment was replicated three times with 15 birds per replicate in a completely randomized design. Packed cell volume and haemoglobin level were not significantly (p>0.05) affected by dietary grit levels while total protein increased across the graded levels of granite grit. Crude protein, crude fibre and nitrogen free extract significantly (p<0.05) improved with increasing grit levels. These parameters improved up to the highest level of grit addition (10.0 g) granite-grit. It was concluded that 10.0 g granite grit per bird per month is beneficial to broiler chickens as it allows for efficient nutrient utilization. Further study to determine the optimum level of granite grit in broiler diet is encouraged since result obtained showed the optimum level was not attained.

Effect of climate change and mollusc invasion on eutrophication and algae blooms in the lagoon ecosystems of the Baltic Sea

NASA Astrophysics Data System (ADS)

Aleksandrov, Sergei; Gorbunova, Julia; Rudinskaya, Lilia

2015-04-01

Coastal lagoons are most vulnerable to impacts of natural environmental and anthropogenic factors. The Curonian Lagoon and Vistula Lagoon are the largest coastal lagoons of the Baltic Sea, relating to the most highly productive water bodies of Europe. The Curonian Lagoon is choke mostly freshwater lagoon, while the Vistula Lagoon is restricted brackish water lagoon. In the last decades the nutrients loading changes, warming trend and biological invasions are observed. The researches (chlorophyll, primary production, nutrients, phytoplankton, benthos, etc) were carried out monthly since 1991 to 2014. The database includes 1600 stations in the Curonian Lagoon, 1650 stations in the Vistula Lagoon. Eutrophication and algae blooms are most important problems. Multiple reductions of nutrients loading from the watershed area in 1990s did not result in considerable improvement of the ecological situation in the lagoons. The Curonian Lagoon may be characterized as hypertrophic water body with "poor" water quality. Climate change in 1990s-2000s combined with other factors (freshwater, slow-flow exchange, high nutrients concentrations) creates conditions for Cyanobacteria "hyperblooms". Hyperbloom of Cyanophyta (average for the growing season Chl > 100 μg/l) were observed during 4 years in 1990s and 7 years in 2000s. The summer water temperature is the key environmental factor determining the seasonal and long-term variability of the primary production and algae blooms. Mean annual primary production in 2010-2014 (600 gC·m-2·year-1) is considerable higher, than in the middle of 1970s (300 gC·m-2·year-1). The local climate warming in the Baltic region caused ongoing eutrophication and harmful algae blooms in the Curonian Lagoon despite of significant reduction of nutrients loading in 1990s-2000s. Harmful algal blooms in July-October (chlorophyll to 700-3400 μg/l) result in deterioration of the water chemical parameters, death of fish in the coastal zone and pollution with toxins, symptoms of exposure are observed at different trophic levels (zooplankton, fish). "Hyperblooms" of Cyanobacteria is the most dangerous for coastal towns (Polessk, Zelenogradsk) and tourist resorts (UNESCO National Park "Curonian Spit"). Also, unfavorable effects of eutrophication have been observed in restricted Vistula Lagoon. Mean annual temperature increased by 1.4°С for 40 years, and water warming combined with other factors created conditions for phytoplankton "hyperblooms" (70-80 μg Chl/l) in 1995-2010. Mean annual primary production in 2000s (430 gC·m-2·year-1) is considerable higher, than in the middle of 1970s (300 gC·m-2·year-1). The climate warming was cause ongoing eutrophication and harmful algal blooms in summer in 1990-2010 despite of significant reduction of nutrients loading in the lagoon. After the invasion of the North American filter-feeding bivalve Rangia cuneata the benthic biomass increased by 8 times (360 g/m2), and chlorophyll decreased by 3.5 times (10 μg/l) in 2011. Water quality is significantly improved from "poor" to "satisfactory" level in 2011-2014, e.g., transparency increased by 2 times. The phytoplankton assimilation numbers increased to maximum (300-400 mgC·mgChl-1·day-1), which are discover in aquatic ecosystems, and primary production remained at previous level. Therefore mollusc invasion improved water quality, but Vistula lagoon ecosystem remained at eutrophic-hypertrophic level. This allowed the function to other trophic groups (zooplankton, fish) at a stable long-term level.

Root-zone acidity affects relative uptake of nitrate and ammonium from mixed nitrogen sources

NASA Technical Reports Server (NTRS)

Vessey, J. K.; Henry, L. T.; Chaillou, S.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

1990-01-01

Soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 21 days on 4 sources of N (1.0 mM NO3-, 0.67 mM NO3- plus 0.33 mM NH4+, 0.33 mM NO3- plus 0.67 mM NH4+, and 1.0 mM NH4+) in hydroponic culture with the acidity of the nutrient solution controlled at pH 6.0, 5.5, 5.0, and 4.5. Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5. Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH. Uptake of NO3- and NH4+ was monitored daily by ion chromatography as depletion of these ions from the replenished hydroponic solutions. At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution. In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0. As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased. Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH. The data indicate a negative effect of declining root-zone pH on NH4+ uptake and supports a hypothesis that the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.

Metabolic Regulation of Manganese Superoxide Dismutase Expression via Essential Amino Acid Deprivation*

PubMed Central

Aiken, Kimberly J.; Bickford, Justin S.; Kilberg, Michael S.; Nick, Harry S.

2008-01-01

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging. PMID:18187411

Metabolic regulation of manganese superoxide dismutase expression via essential amino acid deprivation.

PubMed

Aiken, Kimberly J; Bickford, Justin S; Kilberg, Michael S; Nick, Harry S

2008-04-18

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging.

Effect of cooking time on some nutrient and antinutrient components of bambaragroundnut seeds.

PubMed

Omoikhoje, Stanley Omoh; Aruna, Mohammed Bashiru; Bamgbose, Adeyemi Mustapha

2009-02-01

The proximate composition, gross energy, mineral composition, percentage sugar, oligosaccharides and antinutrient substances of bambaragroundnut seeds subjected to different cooking times were determined. The seeds were cooked for 30, 60, 90 and 120 min. Results of the proximate analysis showed that only the ether extract and ash were significantly (P < 0.05) reduced as the cooking time increased. In contrast, gross energy values significantly (P < 0.05) increased with increased cooking time. Amongst, the mineral elements assayed, calcium, magnesium and iron were significantly (P < 0.05) increased, while phosphorous, potassium, sodium and copper were reduced significantly (P > 0.05) with inreased cooking time. Percentage sucrose and glucose of bambaragroundnut seeds were significantly (P < 0.05) lowest in the raw form, but increased progressively with increased of cooking time. Raffinose and stachyose levels were reduced significantly by increased cookinf time (P < 0.05) with the least value in seeds cooked for 120 min. Trypsin inhibitor, hemagglutinin and tannin were completely eliminated in seeds cooked for 60 min or longer, but the phytin level was reduced significantly (P < 0.05) by cooking. For a significant detoxification of antinutrient substances and for optimal bioavailability of the component nutrients of bambaragroundnut seeds, an optimum cooking time of 60 min at 100 degrees C is therefore recommended.

Factors promoting survival of bacteria in chlorinated water supplies.

PubMed Central

LeChevallier, M W; Cawthon, C D; Lee, R G

1988-01-01

Results of our experiments showed that the attachment of bacteria to surfaces provided the greatest increase in disinfection resistance. Attachment of unencapsulated Klebsiella pneumoniae grown in medium with high levels of nutrients to glass microscope slides afforded the microorganisms as much as a 150-fold increase in disinfection resistance. Other mechanisms which increased disinfection resistance included the age of the biofilm, bacterial encapsulation, and previous growth conditions (e.g., growth medium and growth temperature). These factors increased resistance to chlorine from 2- to 10-fold. The choice of disinfectant residual was shown to influence the type of resistance mechanism observed. Disinfection by free chlorine was affected by surfaces, age of the biofilm, encapsulation, and nutrient effects. Disinfection by monochloramine, however, was only affected by surfaces. Importantly, results showed that these resistance mechanisms were multiplicative (i.e., the resistance provided by one mechanism could be multiplied by the resistance provided by a second mechanism). PMID:3288119

Seed removal by scatter-hoarding rodents: the effects of tannin and nutrient concentration.

PubMed

Wang, Bo; Yang, Xiaolan

2015-04-01

The mutualistic interaction between scatter-hoarding rodents and seed plants have a long co-evolutionary history. Plants are believed to have evolved traits that influence the foraging behavior of rodents, thus increasing the probability of seed removal and caching, which benefits the establishment of seedlings. Tannin and nutrient content in seeds are considered among the most essential factors in this plant-animal interaction. However, most previous studies used different species of plant seeds, rendering it difficult to tease apart the relative effect of each single nutrient on rodent foraging behavior due to confounding combinations of nutrient contents across seed species. Hence, to further explore how tannin and different nutritional traits of seed affect scatter-hoarding rodent foraging preferences, we manipulated tannin, fat, protein and starch content levels, and also seed size levels by using an artificial seed system. Our results showed that both tannin and various nutrients significantly affected rodent foraging preferences, but were also strongly affected by seed size. In general, rodents preferred to remove seeds with less tannin. Fat addition could counteract the negative effect of tannin on seed removal by rodents, while the effect of protein addition was weaker. Starch by itself had no effect, but it interacted with tannin in a complex way. Our findings shed light on the effects of tannin and nutrient content on seed removal by scatter-hoarding rodents. We therefore, believe that these and perhaps other seed traits should interactively influence this important plant-rodent interaction. However, how selection operates on seed traits to counterbalance these competing interests/factors merits further study. Copyright © 2015 Elsevier B.V. All rights reserved.

Comprehensive biometric, biochemical and histopathological assessment of nutrient deficiencies in gilthead sea bream fed semi-purified diets.

PubMed

Ballester-Lozano, Gabriel F; Benedito-Palos, Laura; Estensoro, Itziar; Sitjà-Bobadilla, Ariadna; Kaushik, Sadasivam; Pérez-Sánchez, Jaume

2015-09-14

Seven isoproteic and isolipidic semi-purified diets were formulated to assess specific nutrient deficiencies in sulphur amino acids (SAA), n-3 long-chain PUFA (n-3 LC-PUFA), phospholipids (PL), P, minerals (Min) and vitamins (Vit). The control diet (CTRL) contained these essential nutrients in adequate amounts. Each diet was allocated to triplicate groups of juvenile gilthead sea bream fed to satiety over an 11-week feeding trial period. Weight gain of n-3 LC-PUFA, P-Vit and PL-Min-SAA groups was 50, 60-75 and 80-85 % of the CTRL group, respectively. Fat retention was decreased by all nutrient deficiencies except by the Min diet. Strong effects on N retention were found in n-3 LC-PUFA and P fish. Combined anaemia and increased blood respiratory burst were observed in n-3 LC-PUFA fish. Hypoproteinaemia was found in SAA, n-3 LC-PUFA, PL and Vit fish. Derangements of lipid metabolism were also a common disorder, but the lipodystrophic phenotype of P fish was different from that of other groups. Changes in plasma levels of electrolytes (Ca, phosphate), metabolites (creatinine, choline) and enzyme activities (alkaline phosphatase) were related to specific nutrient deficiencies in PL, P, Min or Vit fish, whereas changes in circulating levels of growth hormone and insulin-like growth factor I primarily reflected the intensity of the nutritional stressor. Histopathological scoring of the liver and intestine segments showed specific nutrient-mediated changes in lipid cell vacuolisation, inflammation of intestinal submucosa, as well as the distribution and number of intestinal goblet and rodlet cells. These results contribute to define the normal range of variation for selected biometric, biochemical, haematological and histochemical markers.

Modeling long-term changes in tundra carbon balance following wildfire, climate change, and potential nutrient addition.

PubMed

Jiang, Yueyang; Rastetter, Edward B; Shaver, Gaius R; Rocha, Adrian V; Zhuang, Qianlai; Kwiatkowski, Bonnie L

2017-01-01

To investigate the underlying mechanisms that control long-term recovery of tundra carbon (C) and nutrients after fire, we employed the Multiple Element Limitation (MEL) model to simulate 200-yr post-fire changes in the biogeochemistry of three sites along a burn severity gradient in response to increases in air temperature, CO 2 concentration, nitrogen (N) deposition, and phosphorus (P) weathering rates. The simulations were conducted for severely burned, moderately burned, and unburned arctic tundra. Our simulations indicated that recovery of C balance after fire was mainly determined by the internal redistribution of nutrients among ecosystem components (controlled by air temperature), rather than the supply of nutrients from external sources (e.g., nitrogen deposition and fixation, phosphorus weathering). Increases in air temperature and atmospheric CO 2 concentration resulted in (1) a net transfer of nutrient from soil organic matter to vegetation and (2) higher C : nutrient ratios in vegetation and soil organic matter. These changes led to gains in vegetation biomass C but net losses in soil organic C stocks. Under a warming climate, nutrients lost in wildfire were difficult to recover because the warming-induced acceleration in nutrient cycles caused further net nutrient loss from the system through leaching. In both burned and unburned tundra, the warming-caused acceleration in nutrient cycles and increases in ecosystem C stocks were eventually constrained by increases in soil C : nutrient ratios, which increased microbial retention of plant-available nutrients in the soil. Accelerated nutrient turnover, loss of C, and increasing soil temperatures will likely result in vegetation changes, which further regulate the long-term biogeochemical succession. Our analysis should help in the assessment of tundra C budgets and of the recovery of biogeochemical function following fire, which is in turn necessary for the maintenance of wildlife habitat and tundra vegetation. © 2016 by the Ecological Society of America.

Improving Nutrient Release of Wall-disruption Bee Pollen with a Combination of Ultrasonication and High Shear Technique.

PubMed

Wu, Wei; Wang, Kai; Qiao, Jiangtao; Dong, Jie; Li, Zhanping; Zhang, Hongcheng

2018-06-22

Bee pollen, collected by honey bees, contains a substantial amount of nutrients and has a high nutritive value. However, a high level of nutrients can be difficult to be digested and absorbed due to the complex wall of bee pollen. We observed that amino acids were mostly distributed inside cell wall of lotus bee pollen, rape bee pollen, apricot bee pollen, wuweizi bee pollen and camellia bee pollen, using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Thus, five species of bee pollen were wall-disrupted with a combination of ultrasonication and high shear technique (US-HS). After the treatment, bee pollen walls were entirely broken into fragments, and a high number of nutrients were released. The contents of amino acids, fatty acids, protein, crude fat, reducing sugar, β-carotene, calcium, iron, zinc, selenium obviously increased after wall-disruption. Overall, our study demonstrates that US-HS can disrupt bee pollen wall to release nutrients. Therefore, further studies are being conducted to compare the digestibility and absorptivity of pollen nutrients before and after wall-disruption. Additionally, TOF-SIMS seems to be a reliable mapping technique for determining the distribution of food ingredients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Expected frontiers: Incorporating weather uncertainty into a policy analysis using an integrated bi-level multi-objective optimization framework

EPA Science Inventory

Weather is the main driver in both plant use of nutrients and fate and transport of nutrients in the environment. In previous work, we evaluated a green tax for control of agricultural nutrients in a bi-level optimization framework that linked deterministic models. In this study,...

Effect of phosphorous concentrations on sedimentary distributions and isotopic composition of algal lipid biomarkers in lakes from central Switzerland

NASA Astrophysics Data System (ADS)

Ladd, N.; Dubois, N.; Schubert, C. J.

2015-12-01

Lakes in the Swiss central plateau experienced increasing anthropogenic phosphorous loading throughout much of the 20th century. Since the 1980s concerted remediation efforts on the part of the Swiss government have significantly reduced P concentrations in most lakes and reversed previous eutrophication. However, P concentrations remain elevated above their preindustrial levels in many sites. High quality monitoring of lake nutrient levels since the 1950s, along with several lakes of wide-ranging P concentrations in close proximity, make central Switzerland an ideal location for studying the ways in which nutrient loading affects the organic composition of lacustrine sediments. Results of such studies can be used to develop proxies of eutrophication in sites where fewer historical data exist, and to reconstruct historical P concentrations in local lakes from the time before record keeping began. We analyzed the distributions of algal lipid biomarkers from surface sediment and sediment traps collected in the spring of 2015 from ten lakes with variable P concentrations in central Switzerland. Sedimentary lipid distributions from these lakes confirm that biomarkers associated with algal and cyanobacterial sources are more abundant in the sediment of lakes with greater P loading. The dry sedimentary concentrations of biomarkers such as brassicasterol (primarily diatom source) and diplopterol (cyanobacteria source), as well as the less source specific short-chain n-alkanols, linearly increase from 0.3 - 1.9 μg/g as total phosphorous in the upper water column increases by 1 μg/L over a range of 7 - 50 μg/L. We also present preliminary hydrogen isotope data from these biomarkers. Hydrogen isotopes of algal lipids primarily reflect the source water in which the algae grew, and this relationship has been developed as a paleohydrologic proxy. However, laboratory cultures of marine algae demonstrate that they discriminate more against 2H under nutrient replete conditions. We present the first field assessment of how nutrient availability influences 2H fractionation in freshwater algae, and demonstrate how such measurements can be used to infer past information about anthropogenic nutrient loading.

Water Quality in Big Cypress National Preserve and Everglades National Park - Trends and Spatial Characteristics of Selected Constituents

USGS Publications Warehouse

Miller, Ronald L.; McPherson, Benjamin F.; Sobczak, Robert; Clark, Christine

2004-01-01

Seasonal changes in water levels and flows in Big Cypress National Preserve (BICY) and Everglades National Park (EVER) affect water quality. As water levels and flows decline during the dry season, physical, geochemical and biological processes increase the breakdown of organic materials and the build-up of organic waste, nutrients, and other constituents in the remaining surface water. For example, concentrations of total phosphorus in the marsh are less than 0.01 milligram per liter (mg/L) during much of the year. Concentrations can rise briefly above this value during the dry season and occasionally exceed 0.1 mg/L under drought conditions. Long-term changes in water levels, flows, water management, and upstream land use also affect water quality in BICY and EVER, based on analysis of available data (1959-2000). During the 1980's and early 1990's, specific conductance and concentrations of chloride increased in the Taylor Slough and Shark River Slough. Chloride concentrations more than doubled from 1960 to 1990, primarily due to greater canal transport of high dissolved solids into the sloughs. Some apparent long-term trends in sulfate and total phosphorus were likely attributable, at least in part, to high percentages of less-than and zero values and to changes in reporting levels over the period of record. High values in nutrient concentrations were evident during dry periods of the 1980's and were attributable either to increased canal inflows of nutrient-rich water, increased nutrient releases from breakdown of organic bottom sediment, or increased build-up of nutrient waste from concentrations of aquatic biota and wildlife in remaining ponds. Long-term changes in water quality over the period of record are less pronounced in the western Everglades and the Big Cypress Swamp; however, short-term seasonal and drought-related changes are evident. Water quality varies spatially across the region because of natural variations in geology, hydrology, and vegetation and because of differences in water management and land use. Nutrient concentrations are relatively low in BICY and EVER compared with concentrations in parts of the northern Everglades that are near agricultural and urban lands. Concentrations of total phosphorus generally are higher in BICY (median values, 1991-2000, were mostly greater than 0.015 mg/L) than in EVER (median values, 1991-2000, less than 0.01 mg/L), probably because of higher phosphorus in natural sources such as shallow soils, rocks, and ground water in the Big Cypress region than in the Everglades region. Conversely, concentrations of chloride and sulfate are higher in EVER (median values in Shark River Slough, 1991-2000, mostly greater than 2 mg/L sulfate and 50 mg/L chloride) than in BICY (median values, 1991-2000, less than 1 mg/L sulfate and at most sites less than 20 mg/L chloride), probably because of the canal transport system, which conveys more water from an agricultural source into EVER than into BICY. Trace elements and contaminants such as pesticides and other toxic organic compounds are in relatively low concentrations in BICY and EVER compared with concentrations in parts of the northern Everglades near agricultural and urban sources. Concentrations rarely exceeded aquatic life criteria in BICY and EVER. Atrazine was the only pesticide found in water that exceeded the criteria (in 2 out of 304 samples). The pesticides heptachlor expoxide, lindane, and p,p?-DDE exceeded criteria in canal bed sediments in 1, 2, and 16 percent of the samples, respectively.

Factors influencing inactivation of Klebsiella pneumoniae by chlorine and chloramine.

PubMed

Goel, Sudha; Bouwer, Edward J

2004-01-01

Inactivation of Klebsiella pneumoniae cultures by chlorine and chloramine was evaluated under different growth conditions by varying nutrient media dilution, concentrations of essential inorganic nutrients (FeCl3, MgSO4, phosphate, and ammonium salts), and temperature. All inactivation assays were performed at room temperature (22-23 degrees C) and near neutral pH (7.2-7.5). C*T(99.9) values for chlorine increased >20-fold and for chloramine increased 2.6-fold when cells were grown in 100-fold diluted nutrient broth (2NB) solutions (final TOC of 35-40 mg/L). Background levels of Mg: 6.75 x 10(-2) mM and Fe: 3.58 x 10(-5) mM or high levels of FeCl3 (0.01 mM) and MgSO4 (1 mM) during growth resulted in the highest resistances to chlorine with C*T(99.9) values of 13.06 (+/-0.91) and 13.78 (+/-1.97) mg-min/L, respectively. Addition of low levels of FeCl3 (0.001 mM) and MgSO4 (0.1 mM) to K. pneumoniae cultures during growth resulted in the lowest bacterial resistances to inactivation; C*T(99.9) values ranged from 0.28 (+/-0.06) to 1.88 (+/-0.53)mg-min/L in these cultures. Increase in growth temperature from 22.5 degrees C to 35 degrees C for unamended 2NB cultures resulted in a 42-fold decrease in C*T(99.9) values for chlorine. A similar change in temperature resulted in no significant change in C*T(99.9) values for chloramine. These results indicate that inactivation of K. pneumoniae cultures by chlorine was highly sensitive to changes in growth conditions unlike inactivation by chloramine.

Nutrient Uptake and Outcome network (NUOnet): Connecting a Wide Range of Natural Resource Conservation Networks

USDA-ARS?s Scientific Manuscript database

Nutrient application and its uptake by crops are essential to increasing agricultural production, which is essential to feed a growing world population. Efficiency in management of nutrients could be increased with conservation practices that reduce nutrient losses to the environment and promote con...

Shifts in symbiotic associations in plants capable of forming multiple root symbioses across a long-term soil chronosequence.

PubMed

Albornoz, Felipe E; Lambers, Hans; Turner, Benjamin L; Teste, François P; Laliberté, Etienne

2016-04-01

Changes in soil nutrient availability during long-term ecosystem development influence the relative abundances of plant species with different nutrient-acquisition strategies. These changes in strategies are observed at the community level, but whether they also occur within individual species remains unknown. Plant species forming multiple root symbioses with arbuscular mycorrhizal (AM) fungi, ectomycorrhizal (ECM) fungi, and nitrogen-(N) fixing microorganisms provide valuable model systems to examine edaphic controls on symbioses related to nutrient acquisition, while simultaneously controlling for plant host identity. We grew two co-occurring species, Acacia rostellifera (N2-fixing and dual AM and ECM symbioses) and Melaleuca systena (AM and ECM dual symbioses), in three soils of contrasting ages (c. 0.1, 1, and 120 ka) collected along a long-term dune chronosequence in southwestern Australia. The soils differ in the type and strength of nutrient limitation, with primary productivity being limited by N (0.1 ka), co-limited by N and phosphorus (P) (1 ka), and by P (120 ka). We hypothesized that (i) within-species root colonization shifts from AM to ECM with increasing soil age, and that (ii) nodulation declines with increasing soil age, reflecting the shift from N to P limitation along the chronosequence. In both species, we observed a shift from AM to ECM root colonization with increasing soil age. In addition, nodulation in A. rostellifera declined with increasing soil age, consistent with a shift from N to P limitation. Shifts from AM to ECM root colonization reflect strengthening P limitation and an increasing proportion of total soil P in organic forms in older soils. This might occur because ECM fungi can access organic P via extracellular phosphatases, while AM fungi do not use organic P. Our results show that plants can shift their resource allocation to different root symbionts depending on nutrient availability during ecosystem development.

Nitrogen Flux in Watersheds: The Role of Soil Distributions and Climate in Nitrogen Flux to the Coastal Ecosystems

NASA Astrophysics Data System (ADS)

Showers, W. J.; Reyes, M. M.; Genna, B. J.

2009-12-01

Quantifying the flux of nitrate from different landscape sources in watersheds is important to understand the increased flux of nitrogen to coastal ecosystems. Recent technological advances in chemical sensor networks has demonstrated that chemical variability in aquatic environments are chronically under-sampled, and that many nutrient monitoring programs with monthly or daily sampling rates are inadequate to characterize the dominate seasonal, daily or semi-diurnal fluxes in watersheds. The RiverNet program has measured the nitrate flux in the Neuse River Basin, NC on a 15 minute interval over the past eight years. Significant diurnal variation has been observed in nitrate concentrations during high and low flow periods associated with waste water treatment plants in urban watersheds that are not present in agricultural watersheds. Discharge and N flux in the basin also has significant inter-annual variations associated with El Nino oscillations modified by the North Atlantic oscillation. Positive JMA and NAO indexes are associated with increased groundwater levels, nutrient fluxes, and estuary fish kills. To understand how climate oscillation affect discharge and nutrient fluxes, we have monitored runoff/drainages and groundwater inputs adjacent to a large waste application field over the past 4 years, and used the nitrate inputs as a tracer. Surface water run off is well correlated to precipitation patterns and is the largest nutrient flux into the river. Groundwater inputs are variable spatially and temporally, and are controlled by geology and groundwater levels. Hydric soil spatial distributions are an excellent predictor of nutrient transport across landscapes, and is related to the distribution of biogeochemical “hotspots” The isotopic composition of oxygen and nitrogen in dissolved nitrate indicate that sources change with discharge state, and that atmospherically deposited nitrogen is only important to river fluxes in forested and urban watersheds. These results also indicate that the contribution of wastewater treatment plants from urban watersheds has been greatly under-estimated in current models. Prediction of future changes in discharge and nutrient flux by the modeling of climate oscillations has important implications for water resources policy and drought management for public policy and utility managers.

Interactive effects of redox intensity and phosphate availability on growth and nutrient relations of Cladium jamaicense (Cyperaceae)

USGS Publications Warehouse

Lissner, J.; Mendelssohn, I.A.; Lorenzen, B.; Brix, H.; McKee, K.L.; Miao, S.L.

2003-01-01

Expansion of Typha domingensis into areas previously dominated by Cladium jamaicense in the Florida Everglades has been linked to anthropogenic phosphorus (P) enrichment and increased hydroperiod. The principal stress factor for plants in flooded soils is biochemical reduction, the intensity of which is measured as redox potential (Eh). The objective of this study was to assess the growth response of C. jamaicense to Eh (-150, +150, and +600 mV) and P availability (10, 80, and 500 ??g P/L). Plants were grown hydroponically in a factorial experiment using titanium (Ti3+) citrate as an Eh buffer. Treatment effects on growth, biomass partitioning, and tissue nutrients were recorded. Growth approximately doubled in response to a 50-fold increase in P availability. Low redox significantly reduced growth and tissue P concentration. While plant P concentrations increased 20-fold between the 10 and 500 ??g P/L treatments, P concentrations were 50-100% higher at +600 mV than at -150 mV within each phosphate level. At high Eh, C. jamaicense appears well adapted to low nutrient environments because of its low P requirement and high retention of acquired E However, at low Eh the ability to acquire or conserve acquired P decreases and as a consequence, higher phosphate levels are required to sustain growth. Findings of this study indicate that young C. jamaicense exhibits low tolerance to strongly reducing conditions when phosphate is scarce.

Effect of soil in nutrient cycle assessment at dairy farms

NASA Astrophysics Data System (ADS)

van Leeuwen, Maricke; de Boer, Imke; van Dam, Jos; van Middelaar, Corina; Stoof, Cathelijne

2016-04-01

Annual farm nutrient cycle assessments give valuable insight in the nutrient cycles and nutrient losses at dairy farms. It describes nutrient use efficiencies for the entire farm and for the underlying components cattle, manure, crops and soil. In many modelling studies, soil is kept as a constant factor, while soil quality is vital for soil functioning of the ecosystem. Improving soil quality will improve the nutrient cycle, and will also have positive effect on the soil functions crop production, water cycling and greenhouse gas mitigation. Spatial variation of soil properties within a farm, however, are not included in annual nutrient cycle assessments. Therefore it is impossible to identify fields where most profit can be gained by improving farm management at field level, and it is not possible to identify and to quantify nutrient flow path ways. The aim of this study is to develop a framework to improve the annual nutrient cycle assessment at Dutch dairy farms, by including soil properties and their spatial variation within farms. Soil type and soil quality will be described by visual soil assessment of soil quality characteristics. The visual observations will be linked to the nutrient cycle assessment, using soil-hydrological model SWAP. We will demonstrate how soil quality at field level can impact on crop production, eutrophication potential and greenhouse gas potential at farm level. Also, we will show how this framework can be used by farmers to improve their farm management. This new approach is focusing on annual nutrient cycle assessment, but could also be used in life cycle assessment. It will improve understanding of soil functioning and dairy farm management.

Associations between omega-3 fatty acids, selenium content, and mercury levels in wild-harvested fish from the Dehcho Region, Northwest Territories, Canada.

PubMed

Reyes, Ellen S; Aristizabal Henao, Juan J; Kornobis, Katherine M; Hanning, Rhona M; Majowicz, Shannon E; Liber, Karsten; Stark, Ken D; Low, George; Swanson, Heidi K; Laird, Brian D

2017-01-01

To better understand the risks and benefits of eating wild-harvested fish from the Northwest Territories, Canada, levels of total mercury (HgT) and selenium (Se) and composition of omega-3 fatty acid (n-3 FA) were measured in muscle tissue of fish harvested from lakes in the Dehcho Region, Northwest Territories, Canada. Average HgT levels ranged from 0.057 mg/kg (cisco) to 0.551 mg/kg (northern pike), while average n-3 FA concentrations ranged from 101 mg/100 g (burbot) to 1,689 mg/100 g (lake trout). In contrast to HgT and n-3 FA, mean Se concentrations were relatively similar among species. Consequently, species such as lake whitefish, cisco, and longnose sucker displayed the highest nutrient levels relative to HgT content. Levels of HgT tended to increase with fish size, while Se and n-3 FA levels were typically not associated with fork length or fish weight. Interestingly, HgT concentration was occasionally inversely related to tissue nutrient content. Significant negative correlations were observed between Hg and n-3 FA for lake trout, northern pike, and walleye. There were also significant negative correlations between Hg and Se noted for lake whitefish, cisco, and northern pike. Samples with the highest nutritional content displayed, on occasion, lower levels of HgT. This study provides valuable information for the design of probabilistic models capable of refining public health messaging related to minimizing Hg risks and maximizing nutrient levels in wild-harvested fish in the Canadian subarctic.

Aeolian dust nutrient contributions increase with substrate age in semi-arid ecosystems

NASA Astrophysics Data System (ADS)

Coble, A. A.; Hart, S. C.; Ketterer, M. E.; Newman, G. S.

2013-12-01

Rock-derived nutrients supplied by mineral weathering become depleted over time, and without an additional nutrient source the ecosystem may eventually regress or reach a terminal steady state. Previous studies have demonstrated that aeolian dust act as parent materials of soils and important nutrients to plants in arid regions, but the relative importance of these exogenous nutrients to the function of dry ecosystems during soil development is uncertain. Here, using strontium isotopes as a tracer and a well-constrained, three million year old substrate age gradient, we show that aeolian-derived nutrients become increasingly important to plant-available soil pools and tree (Pinus edulis) growth during the latter stages of soil development in a semi-arid climate. Furthermore, the depth of nutrient uptake increased on older substrates, suggesting that trees in arid regions acquire nutrients from greater depths as ecosystem development progresses presumably in response to nutrient depletion in the more weathered surface soils. Our results contribute to the unification of biogeochemical theory by demonstrating the similarity in roles of atmospheric nutrient inputs during ecosystem development across contrasting climates.

Nutrients versus emerging contaminants-Or a dynamic match between subsidy and stress effects on stream biofilms.

PubMed

Aristi, I; Casellas, M; Elosegi, A; Insa, S; Petrovic, M; Sabater, S; Acuña, V

2016-05-01

Freshwater ecosystems are threatened by multiple anthropogenic stressors, which might be differentiated into two types: those that reduce biological activity at all concentrations (toxic contaminants), and those that subsidize biological activity at low concentrations and reduce it at high concentrations (assimilable contaminants). When occurring in mixtures, these contaminants can have either antagonistic, neutral or synergistic effects; but little is known on their joint effects. We assessed the interaction effects of a mixture of assimilable and toxic contaminants on stream biofilms in a manipulative experiment using artificial streams, and following a factorial design with three nutrient levels (low, medium or high) and either presence or absence of a mixture of emerging contaminants (ciprofloxacin, erythromycin, diclofenac, methylparaben, and sulfamethoxazole). We measured biofilm biomass, basal fluorescence, gross primary production and community respiration. Our initial hypotheses were that biofilm biomass and activity would: increase with medium nutrient concentrations (subsidy effect), but decrease with high nutrient concentrations (stress effect) (i); decrease with emerging contaminants, with the minimum decrease at medium nutrient concentrations (antagonistic interaction between nutrients subsidy and stress by emerging contaminants) and the maximum decrease at high nutrient concentrations (synergistic interaction between nutrients and emerging contaminants stress) (ii). All the measured variables responded linearly to the available nutrients, with no toxic effect at high nutrient concentrations. Emerging contaminants only caused weak toxic effects in some of the measured variables, and only after 3-4 weeks of exposure. Therefore, only antagonistic interactions were observed between nutrients and emerging contaminants, as medium and high nutrient concentrations partly compensated the harmful effects of emerging contaminants during the first weeks of the experiment. Our results show that contaminants with a subsidy effect can alleviate the effects of toxic contaminants, and that long-term experiments are required to detect stress effects of emerging contaminants at environmentally relevant concentrations. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Knockout maternal adiponectin increases fetal growth in mice: potential role for trophoblast IGFBP-1

PubMed Central

Qiao, Liping; Wattez, Jean-Sebastien; Lee, Samuel; Guo, Zhuyu; Schaack, Jerome; Hay, William W.; Moretto Zita, Matteo; Parast, Mana; Shao, Jianhua

2016-01-01

Aims/hypothesis The main objective of this study was to investigate whether maternal adiponectin regulates fetal growth through the endocrine system in the fetal compartment. Methods Adiponectin knockout (Adipoq−/−) mice and in vivo adenovirus-mediated reconstitution were used to study the regulatory effect of maternal adiponectin on fetal growth. Primary human trophoblast cells were treated with adiponectin and a specific peroxisome proliferator-activated receptor α (PPARα) agonist or antagonist to study the underlying mechanism through which adiponectin regulates fetal growth. Results The body weight of fetuses from Adipoq−/− dams was significantly greater than that of wild-type dams at both embryonic day (E)14.5 and E18.5. Adenoviral vector-mediated maternal adiponectin reconstitution attenuated the increased fetal body weight induced by maternal adiponectin deficiency. Significantly increased blood glucose, triacylglycerol and NEFA levels were observed in Adipoq−/− dams, suggesting that nutrient supply contributes to maternal adiponectin-regulated fetal growth. Although fetal blood IGF-1 concentrations were comparable in fetuses from Adipoq−/− and wild-type dams, remarkably low levels of IGF-binding protein 1 (IGFBP-1) were observed in the serum of fetuses from Adipoq−/− dams. IGFBP-1 was identified in the trophoblast cells of human and mouse placentas. Maternal fasting robustly increased IGFBP-1 levels in mouse placentas, while reducing fetal weight. Significantly low IGFBP-1 levels were found in placentas of Adipoq−/− dams. Adiponectin treatment increased IGFBP-1 levels in primary cultured human trophoblast cells, while the PPARα antagonist, MK886, abolished this stimulatory effect. Conclusions/interpretation These results indicate that, in addition to nutrient supply, maternal adiponectin inhibits fetal growth by increasing IGFBP-1 expression in trophoblast cells. PMID:27495989

The Nutrient and Energy Sensor Sirt1 Regulates the Hypothalamic-Pituitary-Adrenal (HPA) Axis by Altering the Production of the Prohormone Convertase 2 (PC2) Essential in the Maturation of Corticotropin-releasing Hormone (CRH) from Its Prohormone in Male Rats*

PubMed Central

Toorie, Anika M.; Cyr, Nicole E.; Steger, Jennifer S.; Beckman, Ross; Farah, George; Nillni, Eduardo A.

2016-01-01

Understanding the role of hypothalamic neuropeptides and hormones in energy balance is paramount in the search for approaches to mitigate the obese state. Increased hypothalamic-pituitary-adrenal axis activity leads to increased levels of glucocorticoids (GC) that are known to regulate body weight. The axis initiates the production and release of corticotropin-releasing hormone (CRH) from the paraventricular nucleus (PVN) of the hypothalamus. Levels of active CRH peptide are dependent on the processing of its precursor pro-CRH by the action of two members of the family of prohormone convertases 1 and 2 (PC1 and PC2). Here, we propose that the nutrient sensor sirtuin 1 (Sirt1) regulates the production of CRH post-translationally by affecting PC2. Data suggest that Sirt1 may alter the preproPC2 gene directly or via deacetylation of the transcription factor Forkhead box protein O1 (FoxO1). Data also suggest that Sirt1 may alter PC2 via a post-translational mechanism. Our results show that Sirt1 levels in the PVN increase in rats fed a high fat diet for 12 weeks. Furthermore, elevated Sirt1 increased PC2 levels, which in turn increased the production of active CRH and GC. Collectively, this study provides the first evidence supporting the hypothesis that PVN Sirt1 activates the hypothalamic-pituitary-adrenal axis and basal GC levels by enhancing the production of CRH through an increase in the biosynthesis of PC2, which is essential in the maturation of CRH from its prohormone, pro-CRH. PMID:26755731

Effect of Fenton pre-oxidation on mobilization of nutrients and efficient subsequent bioremediation of crude oil-contaminated soil.

PubMed

Xu, Jinlan; Kong, Fanxing; Song, Shaohua; Cao, Qianqian; Huang, Tinglin; Cui, Yiwei

2017-08-01

Fenton pre-oxidation and a subsequent bioremediation phase of 80 days were used to investigate the importance of matching concentration of residual indigenous bacteria and nutrient levels on subsequent bioremediation of crude oil. Experiments were performed using either high (>10 7.7 ± 0.2  CFU/g soil) or low (<10 5.9 ± 0.1  CFU/g soil) concentrations of bacteria and three different nutrient levels: enough (C/N > 9.8), moderate (C/N:5-9.8), and lacking nutrient level (C/N < 5) conditions. Weak Fenton pre-oxidation (225 mM H 2 O 2 and 2.9 mM Fe 2+ ) resulted in highly matching between nutrient level and the population of residual indigenous bacteria. Up to 53% of total petroleum hydrocarbon (TPH) and 58% of main hydrocarbon (C 15 C 25 , during the first 10 days) were removed from the soil. Under matching conditions, the activity of indigenous bacteria and nutrient mobilization were enhanced, promoting the bioremediation of crude oil. In addition, the biodegradation of long chain molecules (C 26 C 30 ) required a high level of NH 4 + -N. Copyright © 2017 Elsevier Ltd. All rights reserved.