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1

Cyclopoid and harpacticoid copepods of the Laurentian Great Lakes  

USGS Publications Warehouse

Historical collections of cyclopoid and harpacticoid copepod crustaceans in the Great Lakes have mainly been based on samples taken with plankton nets in deeper waters (>5 m). Of the non-calanoid copepod species known from the Great Lakes, 58 or 64 live primarily on or in the sediments and rarely are collected in plankton samples. Because of their small size, they are rarely retained in the coarse sieves used to concentrate samples of benthic invertebrates. Thus, the abundance and distribution of most species of these two groups of copepods have never been adequately documented in the Great Lakes. We examined the stomach contents of small, bottom-feeding fishes such as slimy sculpin which feed on benthic copepods that live in deep, inaccessible rocky areas of the Great Lakes to collect some of the material. We also collected in shallow nearshore habitats, including wetlands. We present an annotated checklist of cyclopoid and harpacticoid copepods based on published records and our recent collections in the Great Lakes. We have added 14 species of cyclopoid copepods to the Great Lakes record, increasing the total to 30. Because we probably have accounted for most of the cyclopoid species, we provide a key to the identification of this group. We have added 19 species of harpacticoid copepods to the 15 previously known to the Great Lakes, and suspect that additional species remain to be discovered. In individual lakes, there were approximately as many species of cyclopoids as harpacticoids; the total number of species per lake ranged from 35 to 57. The most speciose genera were Bryocamptus (7), Canthocamptus (5), and Moraria (5) in the Harpacticoida, and Diacyclops (6) and Acanthocyclops (5) in the Cyclopoida. The origin of introduced species, our ability to classify copepod habitat, and the ecological significance of copepods are discussed.

Hudson, Patrick L.; Reid, Janet W.; Lesko, Lynn T.; Selgeby, James H.

1998-01-01

2

Mortality of Fish Larvae Exposed to Varying Concentrations of Cyclopoid Copepods  

Microsoft Academic Search

Cyclopoid copepods can prey on freshwater fish larvae. The magnitude of predation is related to the size and concentrations of the cyclopoid copepods and the size of the fish larva; it is also likely to be specific to certain species. We studied 5-d-old larvae of sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis), golden shiner

Emmanuel A. Frimpong; Steve E. Lochmann

2005-01-01

3

DAMAGE TO FISH FRY BY CYCLOPOID COPEPODS  

Microsoft Academic Search

FIGURE 1. Posterior regions of two 6.5 mm fry of the rockbass, Ambloplites rupestris. A. A control animal, with fins intact. B. An animal after being subjected to harrassment by Mesoeyclops edax for one hour, at a population density equivalent to 500 per liter. The dorsal, caudal and ventral fins are frayed and bruised, with many small and a few

CHARLES C. DAVIS

4

Community and trophic structures of pelagic copepods down to greater depths in the western subarctic Pacific (WEST-COSMIC)  

NASA Astrophysics Data System (ADS)

As part of the research program Western Pacific Environment Study on CO 2 Ocean Sequestration for Mitigation of Climate Change (WEST-COSMIC), vertical distribution and community structure of copepods were studied at Station Knot (44°N, 155°E) down to 4000 m depth in the western subarctic Pacific. Vertical carbon flux mediated by copepod communities was also estimated. Both abundance and biomass of copepods were greatest in the near surface layer and decreased with increasing depth. Decrease of abundance with depth was best fitted to a power regression model, while that of biomass was best described by an exponential regression model. Copepod carcasses occurred throughout the layer, and carcasses/living specimens ratios were greatest in the deepest layer (the ratio was 9.3 at 3000-4000 m depth). A total of 98 calanoid copepod species belonging to 38 genera and 15 families occurred in the 0-4000 m water column (Cyclopoida, Harpacticoida and Poecilostomatoida were not identified to species). The number of genera and species showed bimodal vertical distributions with peaks at 500-1000 m and at 2000-3000 m both during day and night. Based on the species similarity indices, copepod community could be classified into epipelagic, mesopelagic and bathypelagic communities. Based on the feeding pattern, copepods were divided into four types: suspension feeders, suspension feeders in diapause, detritivores and carnivores. In terms of abundance, the most dominant group was suspension feeders (mainly the cyclopoid genus Oithona) in the epipelagic zone, and detritivores (mainly Poecilostomatoida genus Oncaea) were dominant in the meso- and bathypelagic zones. In terms of biomass, suspension feeders in diapause (calanoid genera Neocalanus and Eucalanus) were the major component (ca. 70%), especially at 200-2000 m depth. Comparison of vertical flux of particulate carbon with estimated copepod ingestion/egestion rates suggests that the suspension feeding copepods receive sufficient food. For detritivorous copepods, copepod carcasses, a possible food source, are not abundant enough, so other food sources need to be considered. As a food source for carnivorous copepods, the abundance of suspension feeding and detritivorous copepods appears to be high enough to meet their demand. Our calculation showed that an average of 32% of the particulate carbon flux is consumed by copepods in the 0-4000 m water column.

Yamaguchi, Atsushi; Watanabe, Yuji; Ishida, Hiroshi; Harimoto, Takashi; Furusawa, Kazushi; Suzuki, Shinya; Ishizaka, Joji; Ikeda, Tsutomu; Takahashi, Masayuki Mac

2002-06-01

5

Spatial patterns of copepod biodiversity in relation to a tidal front system in the main spawning and nursery area of the Argentine hake Merluccius hubbsi  

NASA Astrophysics Data System (ADS)

Copepods play an important role in marine ecosystems as a direct link of energy transfer between primary producers and higher trophic level consumers, such as fish. In the Argentine Sea, the Patagonian stock of Argentine hake Merluccius hubbsi spawns from late austral spring (December) to early autumn (April) in the northern Patagonian shelf region (43°-45°30?S), in association with a highly productive tidal front system. Since hake larvae prey mainly upon copepods, the objective of this study was to assess the spatial variability in the abundance and diversity of these potential food items in different sectors of the front, as one of the possible factors affecting hake recruitment success. Two complementary mesh sizes (67 and 300 ?m) were used to accurately target the entire copepod size spectrum. The copepod community was dominated by developmental stages < 1 mm in total length (eggs, nauplii, copepodites of cyclopoids and calanoids), and adults of the species Oithona helgolandica, Microsetella norvegica, Ctenocalanus vanus and Drepanopus forcipatus. Their spatial distribution was highly influenced by the across-shelf characteristics of the tidal front system, highlighting the impact of environmental features, mainly bottom temperature and salinity, in shaping the community. Abundances were higher in the transitional relative to the stratified sector of the system. Such sector would provide the appropriate conditions to sustain M. hubbsi larval growth resulting from high availability of adequate prey, the suitable thermal ranges, and the existence of retention mechanisms.

Temperoni, B.; Viñas, M. D.; Martos, P.; Marrari, M.

2014-11-01

6

Colonization of a new man-made river (Marchfeldcanal, Lower Austria) by benthic copepods  

Microsoft Academic Search

The role of copepods in the colonization and emigration processes of benthos and drift of an irrigation canal were studied. During the 3 first years of existence of the canal, fifteen species of copepods were recorded (1 diaptomid, 11 cyclopoids, 3 harpacticoids). Copepod succession in the canal was initially represented by lentic species, then by predatory species like Macrocyclops albidus

Santiago Gaviria

1998-01-01

7

[Molecular-phylogenetic analysis of cyclopoids (Copepoda: Cyclopoida) from Lake Baikal and its water catchment basin].  

PubMed

Baikalian cyclopoids represent one of the richest endemic faunas of freshwater cyclopoid copepods. The genus Diacyclops Kiefer, 1927 is the most numerous by species number in the lake. In this work, molecular-phylogenetic analysis of 14 species and 1 sub-species from Lake Baikal and its water catchment basin is performed. The regions of mitochondrial cytochrom-oxydase I (COI) and of nuclear small-subunit 18S rRNA were used as evolution markers. In the obtained set of nucleotide sequences of COT gene, an effect of synonymous substitution saturation is revealed. Baikalian representatives of the genus Diacyclops form at phylogenetic schemes by two markers a monophyletic griup, it suggest their origin from a common ancestral form. Preliminary estimate of the age of this group is 20-25 My. PMID:21261066

Ma?or, T Iu; Sheveleva, N G; Sukhanova, L V; Timoshkin, O A; Kiril'chik, S V

2010-11-01

8

Observing free-swimming copepods mating  

PubMed Central

Planktonic copepods are small transparent animals swimming in water. To observe how a male finds its mate, special optical systems had to be designed. The animals are treated as phase objects and matched spatial filters allow three-dimensional recordings of the swimming behaviour in a 1-litre vessel. Application of the techniques described shows how a male cyclopoid copepod swims for 20 s in synchronicity with the female before mating. Results stemming from observations with this optical system are published in this volume.

Strickler, J. R.

1998-01-01

9

Colonization of a new man-made river (Marchfeldcanal, Lower Austria) by benthic copepods  

NASA Astrophysics Data System (ADS)

The role of copepods in the colonization and emigration processes of benthos and drift of an irrigation canal were studied. During the 3 first years of existence of the canal, fifteen species of copepods were recorded (1 diaptomid, 11 cyclopoids, 3 harpacticoids). Copepod succession in the canal was initially represented by lentic species, then by predatory species like Macrocyclops albidus that developed with the proliferation of filamentous algae and epibionts during the first two years. Primary consumers appeared from the beginning of the flowing conditions but started to dominate only from the third year. Smaller species associated with the bed sediments like the harpacticoid species Nitocra hibernica, were late colonizers. The latter as well as Paracyclops fimbriatus and Eucyclops serrulatus were the dominant copepod species in the canal. Total copepod density in the benthos ranged from 15,800 to 68,000 ind./m 2, with a mean of 7.6% of the total zoobenthos. Copepods constituted up to 25% of the total faunal drift density, ranging from 50 to 140 ind./m 3. Their highest abundance was observed around midnight. A three-fold increase of the discharge temporarily affected the drift density, but did not change the diel rhythm of the drift. Cyclopoid copepods namely P. fimbriatus (54.77%), copepodid cyclopoids (20.76%) and E. serrulatus (16.11%) formed the main part of the drift samples. The harpacticoid Nitocra hibernica was a minor participant in the drift processes.

Gaviria, Santiago

1998-06-01

10

Energetic costs of swarming behavior for the copepod Dioithona oculata  

Microsoft Academic Search

The cyclopoid copepod Dioithona oculata forms dense swarms within shafts of sunlight that penetrate the mangrove prop-root habitat of islands off the coast of Belize.\\u000a Previous studies, based on in situ video recordings and laboratory studies, have shown that D. oculata is capable of maintaining fixed-position swarms in spite of currents of up to 2?cm?s?1. The purpose of this study

E. J. Buskey

1998-01-01

11

Copepod population in Vellar estuary, Parangipettai coast in relation to environmental conditions.  

PubMed

Distribution and abundance of copepods were studied in relation to environmental conditions at two different ecosystems viz: Neritic (Bay of Bengal) and estuarine (Vellar estuary) of Parangipettai coast from September, 1998 toAugust, 2000. Over the study period, total 85 species of copepods were reported. Among these, the calanoid copepods constituted the major component with 63.52% followed by cyclopoids (29.41%) and harpacticoids (7.05%). The copepods population density was found to be high (2, 53,000 org l(-1)) in estuarine water, while the species diversity was higher (5.47) in neritic water. The observed spatio-temporal variations in the population density and species diversity of copepods were more related to the environmental state of respective study area. PMID:23741792

Santhanam, P; Perumal, P; Ananth, S; Devi, A Shenbaga

2012-11-01

12

Copepod post-embryonic durations: pattern, conformity, and predictability. The realities of isochronal and equiproportional development, and trends in the opepodid-naupliar duration ratio  

Microsoft Academic Search

A collation of post-embryonic durations for freshwater and marine calanoid, cyclopoid and harpacticoid copepods is provided,\\u000a and examined for patterns and conformities which may be of predictive value. Most of the analysis concerns calanoids. Only\\u000a the genus Acartia exhibits evidence of equal stage duration (isochronality). Accordingly, isochronal development must be rejected as a general pattern in copepods — with various

R. C. Hart

1990-01-01

13

The fluid dynamics of swimming by jumping in copepods  

PubMed Central

Copepods swim either continuously by vibrating their feeding appendages or erratically by repeatedly beating their swimming legs, resulting in a series of small jumps. The two swimming modes generate different hydrodynamic disturbances and therefore expose the swimmers differently to rheotactic predators. We developed an impulsive stresslet model to quantify the jump-imposed flow disturbance. The predicted flow consists of two counter-rotating viscous vortex rings of similar intensity, one in the wake and one around the body of the copepod. We showed that the entire jumping flow is spatially limited and temporally ephemeral owing to jump-impulsiveness and viscous decay. In contrast, continuous steady swimming generates two well-extended long-lasting momentum jets both in front of and behind the swimmer, as suggested by the well-known steady stresslet model. Based on the observed jump-swimming kinematics of a small copepod Oithona davisae, we further showed that jump-swimming produces a hydrodynamic disturbance with much smaller spatial extension and shorter temporal duration than that produced by a same-size copepod cruising steadily at the same average translating velocity. Hence, small copepods in jump-swimming are in general much less detectable by rheotactic predators. The present impulsive stresslet model improves a previously published impulsive Stokeslet model that applies only to the wake vortex. PMID:21208972

Jiang, Houshuo; Ki?rboe, Thomas

2011-01-01

14

Sensitivity to ocean acidification parallels natural pCO2 gradients experienced by Arctic copepods under winter sea ice  

PubMed Central

The Arctic Ocean already experiences areas of low pH and high CO2, and it is expected to be most rapidly affected by future ocean acidification (OA). Copepods comprise the dominant Arctic zooplankton; hence, their responses to OA have important implications for Arctic ecosystems, yet there is little data on their current under-ice winter ecology on which to base future monitoring or make predictions about climate-induced change. Here, we report results from Arctic under-ice investigations of copepod natural distributions associated with late-winter carbonate chemistry environmental data and their response to manipulated pCO2 conditions (OA exposures). Our data reveal that species and life stage sensitivities to manipulated OA conditions were correlated with their vertical migration behavior and with their natural exposures to different pCO2 ranges. Vertically migrating adult Calanus spp. crossed a pCO2 range of >140 ?atm daily and showed only minor responses to manipulated high CO2. Oithona similis, which remained in the surface waters and experienced a pCO2 range of <75 ?atm, showed significantly reduced adult and nauplii survival in high CO2 experiments. These results support the relatively untested hypothesis that the natural range of pCO2 experienced by an organism determines its sensitivity to future OA and highlight that the globally important copepod species, Oithona spp., may be more sensitive to future high pCO2 conditions compared with the more widely studied larger copepods. PMID:24297880

Lewis, Ceri N.; Brown, Kristina A.; Edwards, Laura A.; Cooper, Glenn; Findlay, Helen S.

2013-01-01

15

Sensitivity to ocean acidification parallels natural pCO2 gradients experienced by Arctic copepods under winter sea ice.  

PubMed

The Arctic Ocean already experiences areas of low pH and high CO2, and it is expected to be most rapidly affected by future ocean acidification (OA). Copepods comprise the dominant Arctic zooplankton; hence, their responses to OA have important implications for Arctic ecosystems, yet there is little data on their current under-ice winter ecology on which to base future monitoring or make predictions about climate-induced change. Here, we report results from Arctic under-ice investigations of copepod natural distributions associated with late-winter carbonate chemistry environmental data and their response to manipulated pCO2 conditions (OA exposures). Our data reveal that species and life stage sensitivities to manipulated OA conditions were correlated with their vertical migration behavior and with their natural exposures to different pCO2 ranges. Vertically migrating adult Calanus spp. crossed a pCO2 range of >140 ?atm daily and showed only minor responses to manipulated high CO2. Oithona similis, which remained in the surface waters and experienced a pCO2 range of <75 ?atm, showed significantly reduced adult and nauplii survival in high CO2 experiments. These results support the relatively untested hypothesis that the natural range of pCO2 experienced by an organism determines its sensitivity to future OA and highlight that the globally important copepod species, Oithona spp., may be more sensitive to future high pCO2 conditions compared with the more widely studied larger copepods. PMID:24297880

Lewis, Ceri N; Brown, Kristina A; Edwards, Laura A; Cooper, Glenn; Findlay, Helen S

2013-12-17

16

Ecology and role of benthic copepods in northern lakes  

NASA Astrophysics Data System (ADS)

Freshwater benthic Harpacticoida consist of species capable of swimming, but mostly burrowing in organic sediments, and small, vermiform species that are poor swimmers and live in interstitial systems. Freshwater benthic Cyclopoida are either agile epibenthic and often relatively large herbivores, carnivores and omnivores, or small infaunal omnivores. Harpacticoids seem to have few, mainly invertebrate, predators, and consequently low mortality and long life span. These are evolutionarily linked to slow growth and low production to biomass ratio (typically 1-7 a -1). Cyclopoids are characterized by more rapid growth and higher production to biomass ratio (typically 3-13 a -1). Due to their active mode of life, they are preyed upon by fish and other predators, which results in high mortality and a short adult life span. Harpacticoid numbers and biomass may reach 250,000 ind/m 2 and 120 mgC/m 2. True benthic cyclopoids are usually much less abundant (up to 20,000 ind/m 2 and 9 mgC/m 2). Thus, although the quantitative importance of freshwater meiofauna as a whole may often be comparable to that of macrofauna, the few biomass and production data on benthic copepods suggest that at least harpacticoids have a minor role in the benthic food web of northern lakes.

Sarvala, J.

1998-06-01

17

Seasonal variation in community structure and body length of dominant copepods around artificial reefs in Xiaoshi Island, China  

NASA Astrophysics Data System (ADS)

This study aims to investigate the seasonal variations in copepod community structure and prosome length of dominant species from March 2009 to January 2010 around artificial reefs in Xiaoshi Island, Yellow Sea, Weihai, China. Samples were collected using two types of plankton net (Model I and Model II) for different-sized copepods. The number of taxon was calculated from the data of both the net types, while the copepod abundance was done using the samples from Model II only. Sixteen species of planktonic copepods, including 5 dominant species, were recorded. Results reveal that Oithona similis was the first dominant species from March to June, and was replaced by Paracalanus parvus in September; both dominated the copepod community in January. Acartia hongi was the second dominant species from March to September. Centropages abdominalis was the third dominant species from March to June, and was replaced by O. similis in September and Corycaeus affinis in January. C. affinis was the fourth dominant species in September. Population density of the dominant copepods was compared with that of other similar regions. We found that the dominant species were mostly small copepods (<1 mm) except for adult Centrapages abdominalis. Seasonal variation in prosome length of O. similis, C. abdominalis, and C. affinis, and their copepodites were studied for the first time in China. For P. parvus and A. hongi, seasonal trends in prosome length variation were similar with those in Jiaozhou Bay, Yellow Sea, Qingdao, China, in a similar temperate domain. The results are helpful for future calculation of copepod biomass and production, and for investigation of the relationship between copepods and fish resources.

Sun, Xiaohong; Liang, Zhenlin; Zou, Jixin; Wang, Longxiang

2013-03-01

18

Life cycle strategies of epipelagic copepods in the Southern Ocean  

NASA Astrophysics Data System (ADS)

Twelve epipelagic copepod species were reviewed to compare their adaptations to the short primary production season and low temperatures which characterise the Southern Ocean. The species show a spectrum of adaptations, but three broad life cycle strategies were defined: (1) herbivorous in summer, a short reproductive period and winter diapause at depth ( Calanoides acutus and possibly Ctenocalanus citer); (2) predominantly omnivorous/detritivorous diet, an extended period of feeding, growth and reproduction and less reliance on diapause at depth ( Metridia gerlachei, Calanus propinquus, Calanus simillimus, Oithona similis, Microcalanus pygmaeus, and possibly Oncaea curvata and Oithona frigida); (3) overwintering and feeding within sea ice as early nauplii or copepodids ( Stephos longipes and Paralabidocera antarctica). The large species Rhincalanus gigas appears to be intermediate between strategies (1) and (2). Contrasting species from groups (1) and (2), namely C. acutus and O. similis, were selected for more detailed comparison. For C. acutus, maximum (probably food saturated) feeding and egg production rates are well below equivalent values for Calanus spp. at lower latitudes. Likewise, summer growth and moulting rates are slower, and the growth season of this herbivore is only 2-4 months. Therefore, both the low summer temperatures and short primary production season seem to dictate a long (˜1 year) life cycle for C. acutus. A collation of data on O. similis revealed that its abundance increases about tenfold from the Antarctic shelf northwards to the Polar Frontal Zone, where abundances are similar to those in temperate and tropical shelf seas. In contrast to C. acutus, O. similis appears to remain in the epipelagic and reproduce there year-round, although the food sources which sustain this are still uncertain.

Atkinson, Angus

1998-06-01

19

Spatial and long-term temporal variation of meiobenthic-hyperbenthic copepods in Lake Pontchartrain, Louisiana  

NASA Astrophysics Data System (ADS)

The distribution and abundance of the meiobenthic-hyperbenthic copepods of Lake Pontchartrain (a large, 1630 km 2, shallow, mean depth of 3·7m, brackish, 0·3-5‰, lake in Southeastern Louisiana) were characterized monthly from August 1978 to August 1979. Ten stations, all with water depth > 2m, were established and sampled quantitatively by removing four benthic subsamples (containing as much as 25 cm overlying water) from replicated box cores. Averaged across stations over time, total copepod densities ranged from 31-89 × 10 cm -2. A total of only 15 copepod species were identified from benthic samples; 8 harpacticoids, 4 cyclopoids and 3 calanoids. The copepod assemblage in Pontchartrain differs from all other known benthic assemblages in that the species composition is dominated by species which are often associated with the water column; true infaunal species are rare or found in reduced abundance. Four species comprised 90% of all individuals collected. All four are epibenthic or commonly collected as zooplankton and include Scottolana canadensis which comprised 47% of all individuals collected, Halicyclops fosteri which dominated fall collections, Acartia tonsa and Pseudobradya sp. Burrowing species were largely restricted to the more saline eastern stations. The rarity of burrowing species might be related to low salinity, however the highly unstable bottom in Pontchartrain with silty-clayey sediments commonly resuspended into the water column, may also influence burrowers. Cluster analysis reveals diffuse seasonal grouping of stations for all seasons except fall, with spatial groupings from the central and western sides. Physical processes appear to dictate the community structure of benthic-hyperbenthic copepods in Lake Pontchartrain.

Fleeger, J. W.; Sikora, W. B.; Sikora, J. P.

1983-04-01

20

The Kinematics of Swimming and Relocation Jumps in Copepod Nauplii  

PubMed Central

Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella, and copepodites are equipped with highly specialized swimming legs. In some species the nauplius may also propel itself more slowly through the water by beating and rotating the appendages in a different, more complex pattern. We use high-speed video to describe jumping and swimming in nauplii of three species of pelagic copepods: Temora longicornis, Oithona davisae and Acartia tonsa. The kinematics of jumping is similar between the three species. Jumps result in a very erratic translation with no phase of passive coasting and the nauplii move backwards during recovery strokes. This is due to poorly synchronized recovery strokes and a low beat frequency relative to the coasting time scale. For the same reason, the propulsion efficiency of the nauplii is low. Given the universality of the nauplius body plan, it is surprising that they seem to be inefficient when jumping, which is different from the very efficient larger copepodites. A slow-swimming mode is only displayed by T. longicornis. In this mode, beating of the appendages results in the creation of a strong feeding current that is about 10 times faster than the average translation speed of the nauplius. The nauplius is thus essentially hovering when feeding, which results in a higher feeding efficiency than that of a nauplius cruising through the water. PMID:23115647

Andersen Borg, Christian Marc; Bruno, Eleonora; Ki?rboe, Thomas

2012-01-01

21

Egg strings in Euchirella pseudopulchra (Aetideidae) and comments on constraints on egg brooding in planktonic marine copepods  

NASA Astrophysics Data System (ADS)

Adult female Euchirella pseudopulchra Park, 1976 from the California Current System bear a pair of unusual linear ovisacs or "egg strings." Each membrane-bound, single file row of eggs contains 11-14 relatively large ova. Calculations suggest that the geometric arrangement of single file rows of eggs could facilitate oxygen diffusion in O 2-deficient waters. The presence of ventrally carried egg masses in E. pseudopulchra and other members of the Calanoida appears to be associated with evolutionary loss of the fifth swimming legs (P5) in the adult female. We hypothesize that loss of the female P5 would improve hydrodynamic thrust during escape responses and reduce the probability of loss of ventrally brooded ova. We re-examine the relationship between egg size and body size for planktonic marine calanoid and cyclopoid copepods from the mesopelagic and epipelagic zones and compare the advantages of brooding versus broadcast-spawning life histories. The size distribution of adult females of 43 egg-brooding copepod species is bimodal, comprising a number of small-bodied species and large-bodied species, with only one intermediate-sized species (between 10-100 ?g C). The size distribution of 75 broadcast spawners includes a large number (41) of intermediate-sized species. The interrupted size distribution of the egg-brooding species probably reflects enhanced predation risk to intermediate-sized copepods of carrying attached egg masses in the epipelagic zone.

Ohman, M. D.; Townsend, A. W.

1998-06-01

22

Introduction Copepods constitute a fundamentally important link  

E-print Network

the interaction of ingestion, digestion, and egestion. Thus, the gut dynamics are important in deter- mining of ingestion, food movement in the digestive tract, and egestion, for individual copepods. Copepod feeding

Jaffe, Jules

23

Harpacticoid and cyclopoid fauna of groundwater and springs in southern Finland  

NASA Astrophysics Data System (ADS)

The groundwater fauna, of which scarcely anything has previously been studied in formerly glaciated areas, was richest close to the water table and diminished markedly at greater depths. However, few individuals were generally recorded per 1 m 3 of water. Bryocamptus minutus was the most abundant species of copepod at an esker site, the other species recorded being Attheyella crassa, Bryocamptus pygmaeus, Moraria brevipes and Parastenocaris phyllura, and some species from the genus Diacyclops. At a shore bank infiltration site M. brevipes was the most numerous species. However, one esker site examined did not have any animals. Springs, which were grouped into those in a natural state and those under anthropogenic influence, had some species in common with esker groundwater, but also Paracyclops fimbriatus, Acanthocyclops robustus, Acanthocyclops vernalis, Diacyclops bicuspidatus, Megacyclops viridis, and the harpacticoid species Bryocamptus cuspidatus, Bryocamptus echinatus and Canthocamptus staphylinus. Of the spring copepods, P. fimbriatus appeared to withstand the influence of road de-icing with NaCl, but numbers of Moraria brevipes were reduced under this influence. Bryocamptus echinatus was more numerous in springs having a high oxygen content and high pH. The species found in esker groundwaters and springs were in part the same evidently cold-stenotherm species which inhabit the profundal zone of oligotrophic lakes.

Särkkä, Jukka; Levonen, Leena; Mäkelä, Jorma

1998-06-01

24

Diapause in copepods (Crustacea) from ephemeral habitats with different hydroperiods in Everglades National Park (Florida, U.S.A.)  

USGS Publications Warehouse

Water management practices in the Everglades have severely stressed the natural system, particularly by reducing the hydroperiods of much of the region. During the dry season of 1999, we investigated the influence of hydroperiod on the species composition and dormancy patterns of freshwater copepod communities in seasonal wetlands of Everglades National Park, Florida, U.S.A. The habitats were characterized by an annual dry season, from December through June. We sampled at two locations: the Long Pine Key area of the Rocky Glades region (short hydroperiod, ca. 4-5 months), and western Taylor Slough (intermediate hydroperiod, ca. 8-10 months). Both areas have experienced a reduction in natural hydroperiods and an increase in the frequency of dry-down. We collected weekly plankton samples from Rocky Glades solution holes to assess the potential species pool of copepods. To document the taxa capable of surviving dry-down by resting, we performed three immersion trials in which we rehydrated, in laboratory aquaria, sediment patches from solution holes and surface soils from all stations. Only a subset of the planktonic species collected emerged from the dried sediments. The cyclopoids Microcyclops rubellus and Paracyclops poppei were dominant. This is the first record of diapause for P. poppei. Species distributions from the different hydroperiod soil patches indicated that more diapausing species occurred at the sites that dried for shorter periods. Emerging individuals of M. rubellus and P. poppei were mainly ovigerous females, demonstrating a resting strategy seldom before recorded. The cyclopoid Diacyclops nearcticus had not been previously reported to diapause, but they emerged from the dried sediments in our trials. Our collections included six new records for Florida: Diacyclops nearcticus, Megacyclops latipes, Orthocyclops modestus, Elaphoidella marjoryae, Bryocamptus sp. and Bryocamptus cf. newyorkensis. Paracyclops poppei, Macrocyclops fuscus and Arctodiaptomus floridanus are new records for Everglades National Park. Clearly, diapause is an important strategy for the persistence of copepods in short-hydroperiod wetlands. The duration of the dry period appears to be inversely related to the number of species that emerge from diapause.

Bruno, M. C.; Loftus, W. F.; Reid, J. W.; Perry, S. A.

2001-01-01

25

PREPARATION OF COPEPODS FOR HISTOPATHOLOGICAL EXAMINATIONS  

EPA Science Inventory

Various fixatives and processing techniques were utilized to determine the best method of preparing large numbers of copepods for histopathological examination. Dietrich's fixative gave the finest cytological detail and was the best suited for general use....

26

Observing copepods through a genomic lens  

PubMed Central

Background Copepods outnumber every other multicellular animal group. They are critical components of the world's freshwater and marine ecosystems, sensitive indicators of local and global climate change, key ecosystem service providers, parasites and predators of economically important aquatic animals and potential vectors of waterborne disease. Copepods sustain the world fisheries that nourish and support human populations. Although genomic tools have transformed many areas of biological and biomedical research, their power to elucidate aspects of the biology, behavior and ecology of copepods has only recently begun to be exploited. Discussion The extraordinary biological and ecological diversity of the subclass Copepoda provides both unique advantages for addressing key problems in aquatic systems and formidable challenges for developing a focused genomics strategy. This article provides an overview of genomic studies of copepods and discusses strategies for using genomics tools to address key questions at levels extending from individuals to ecosystems. Genomics can, for instance, help to decipher patterns of genome evolution such as those that occur during transitions from free living to symbiotic and parasitic lifestyles and can assist in the identification of genetic mechanisms and accompanying physiological changes associated with adaptation to new or physiologically challenging environments. The adaptive significance of the diversity in genome size and unique mechanisms of genome reorganization during development could similarly be explored. Genome-wide and EST studies of parasitic copepods of salmon and large EST studies of selected free-living copepods have demonstrated the potential utility of modern genomics approaches for the study of copepods and have generated resources such as EST libraries, shotgun genome sequences, BAC libraries, genome maps and inbred lines that will be invaluable in assisting further efforts to provide genomics tools for copepods. Summary Genomics research on copepods is needed to extend our exploration and characterization of their fundamental biological traits, so that we can better understand how copepods function and interact in diverse environments. Availability of large scale genomics resources will also open doors to a wide range of systems biology type studies that view the organism as the fundamental system in which to address key questions in ecology and evolution. PMID:21933388

2011-01-01

27

Copepods and fishes in the Brazilian Amazon  

NASA Astrophysics Data System (ADS)

The Amazon basin comprises the largest river ecosystem in the world (7 million km 2) with annual high and low water peaks and a constant temperature near 29°C. Some 2000 fish species and 40 species of free-living copepods are known to occur in Amazonia. The free-living forms serve as food for most larval fishes and some adults, but they also transmit several parasites including representatives of the nematode family Camallanidae. About three dozen species of parasitic copepods have been described from the Brazilian Amazon. Females of Amazonian parasitic copepods are found on skin, gill filaments, gill rakers or within the nasal fossae. Parasitic copepods are found on fishes that are from a few millimeters long up to those over 2 m in length and they are usually quite host specific. All have body pigmentation in different patterns and colors (frequently blues, such as cerulean, cobalt, spectrum, smalt or campanula). It is suggested that the coloration serves to attract specific host fish. Copepods have evolved adaptations for attachment and feeding, especially in the second antennae and endopods. Examples of progenesis, phoresis and commensalism are shown. Some species produce pathology such as a tourniquet effect, hyperplasia, blood loss and anemia, and can kill fishes by limiting their respiration.

Thatcher, Vernon E.

1998-06-01

28

The Copepods of the Mississippi Delta region  

E-print Network

turbinata (Dana) This species is smaller than the preceding one. It was ti D. ~tfif dl tt fll 1tt abundant copepods at most of the stations. 29 It has been listed I'rom the Gulf by: Davis (1950), King (1950), Grice (1956), Menzel (1956), and Fleminger... turbinata (Dana) This species is smaller than the preceding one. It was ti D. ~tfif dl tt fll 1tt abundant copepods at most of the stations. 29 It has been listed I'rom the Gulf by: Davis (1950), King (1950), Grice (1956), Menzel (1956), and Fleminger...

Gonzalez, Juan Gerardo

2012-06-07

29

The microbiome of North Sea copepods  

NASA Astrophysics Data System (ADS)

Copepods can be associated with different kinds and different numbers of bacteria. This was already shown in the past with culture-dependent microbial methods or microscopy and more recently by using molecular tools. In our present study, we investigated the bacterial community of four frequently occurring copepod species, Acartia sp., Temora longicornis, Centropages sp. and Calanus helgolandicus from Helgoland Roads (North Sea) over a period of 2 years using DGGE (denaturing gradient gel electrophoresis) and subsequent sequencing of 16S-rDNA fragments. To complement the PCR-DGGE analyses, clone libraries of copepod samples from June 2007 to 208 were generated. Based on the DGGE banding patterns of the two years survey, we found no significant differences between the communities of distinct copepod species, nor did we find any seasonality. Overall, we identified 67 phylotypes (>97 % similarity) falling into the bacterial phyla of Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. The most abundant phylotypes were affiliated to the Alphaproteobacteria. In comparison with PCR-DGGE and clone libraries, phylotypes of the Gammaproteobacteria dominated the clone libraries, whereas Alphaproteobacteria were most abundant in the PCR-DGGE analyses.

Gerdts, G.; Brandt, P.; Kreisel, K.; Boersma, M.; Schoo, K. L.; Wichels, A.

2013-12-01

30

Evidence for sex pheromones in planktonic copepods  

Microsoft Academic Search

When in the presence of potential mates, males of the copepods Ezcrytemorn affinis, Eurytemora he&man& and Pseuclodiuptomus coronatus performed mate-seeking behavior which appeared to be oriented. Males of E. affinis and P. coronutus located stationary females from up to 20 mm away. Males of E. affinis also chased and found secured females moved by a mechanical clevice. Eurytemora affinis males

STEVEN K. KATONA

1973-01-01

31

Computational analysis and functional expression of ancestral copepod luciferase.  

PubMed

We recently reported the cDNA sequences of 11 copepod luciferases from the superfamily Augaptiloidea in the order Calanoida. They were classified into two groups, Metridinidae and Heterorhabdidae/Lucicutiidae families, by phylogenetic analyses. To elucidate the evolutionary processes, we have now further isolated 12 copepod luciferases from Augaptiloidea species (Metridia asymmetrica, Metridia curticauda, Pleuromamma scutullata, Pleuromamma xiphias, Lucicutia ovaliformis and Heterorhabdus tanneri). Codon-based synonymous/nonsynonymous tests of positive selection for 25 identified copepod luciferases suggested that positive Darwinian selection operated in the evolution of Heterorhabdidae luciferases, whereas two types of Metridinidae luciferases had diversified via neutral mechanism. By in silico analysis of the decoded amino acid sequences of 25 copepod luciferases, we inferred two protein sequences as ancestral copepod luciferases. They were expressed in HEK293 cells where they exhibited notable luciferase activity both in intracellular lysates and cultured media, indicating that the luciferase activity was established before evolutionary diversification of these copepod species. PMID:23886588

Takenaka, Yasuhiro; Noda-Ogura, Akiko; Imanishi, Tadashi; Yamaguchi, Atsushi; Gojobori, Takashi; Shigeri, Yasushi

2013-10-10

32

Mobiline peritrich riders on Australian calanoid copepods  

Microsoft Academic Search

Calanoid copepods from billabongs near Wodonga, Victoria, Australia were found to be infested with a disc-shaped mobiline peritrich ciliate belonging to the genus Trichodina. Biometrical data, including mean body diameter (43.6 µm), mean adhesive disc diameter (35.9 µm), mean denticle ring diameter (20.1 µm), modal denticle number (17), modal number of radial pins per denticle (9), and denticle shape and

John D. Green; Russell J. Shiel

2000-01-01

33

Copepod Foraging on the Basis of Food Nutritional Quality: Can Copepods Really Choose?  

PubMed Central

Copepods have been considered capable of selective feeding based on several factors (i.e., prey size, toxicity, and motility). However, their selective feeding behaviour as a function of food quality remains poorly understood, despite the potential impact of such a process on copepod fitness and trophodynamics. In this study, we aimed to evaluate the ability of copepods to feed selectively according to the nutritional value of the prey. We investigated the feeding performance of the calanoid copepod Acartia grani under nutritionally distinct diets of the dinoflagellate Heterocapsa sp. (nutrient-replete, N-depleted and P-depleted) using unialgal suspensions and mixtures of prey (nutrient-replete vs. nutrient-depleted). Despite the distinct cell elemental composition among algal treatments (e.g., C:N:P molar ratios) and the clear dietary impact on egg production rates (generally higher number of eggs under a nutrient-replete diet), no impact on copepod feeding rates was observed. All unialgal suspensions were cleared at similar rates, and this pattern was independent of food concentration. When the prey were offered as mixtures, we did not detect selective behaviour in either the N-limitation (nutrient-replete vs. N-depleted Heterocapsa cells) or P-limitation (nutrient-replete vs. P-depleted Heterocapsa cells) experiments. The lack of selectivity observed in the current study contrasts with previous observations, in which stronger nutritional differences were tested. Under normal natural circumstances, nutritional differences in natural prey assemblages might not be sufficiently strong to trigger a selective response in copepods based on that factor alone. In addition, our results suggest that nutritional quality might depend not only on the growing conditions but also on the inherent taxonomical properties of the prey. PMID:24386411

Isari, Stamatina; Ant?, Meritxell; Saiz, Enric

2013-01-01

34

DEBATE Open Access Observing copepods through a genomic lens  

E-print Network

's freshwater and marine ecosystems, sensitive indicators of local and global climate change, key ecosystem of waterborne disease. Copepods sustain the world fisheries that nourish and support human populations. Although aspects of the biology, behavior and ecology of copepods has only recently begun to be exploited

Lee, Carol Eunmi

35

Locomotion in copepods: pattern of movements and energetics of Cyclops  

Microsoft Academic Search

The cost of swimming in copepods has generally been estimated through the application of fluid dynamics theory to data on velocity and acceleration obtained by means of movies. It has also been estimated through the changes in fat content of copepods after sustained swimming (i.e. vertical migration). However, the range of estimated costs of locomotion is exceedingly large (from 0.1%

M. Alcaraz; J. R. Strickler

1988-01-01

36

Occurrence of copepod carcasses in the lower Chesapeake Bay and their decomposition by ambient microbes  

Microsoft Academic Search

We tested and refined the Neutral Red staining method for separating live and dead copepods in natural samples. Live copepods were stained red whereas dead copepods remained unstained. The staining results were not affected by method of killing, time of death or staining time. Tow duration had no significant effect on the percent dead copepods collected. The Neutral Red staining

Kam W. Tang; Curtis S. Freund; Christopher L. Schweitzer

2006-01-01

37

Molecular and microscopic evidence of viruses in marine copepods  

PubMed Central

As dominant members of marine mesozooplankton communities, copepods play critical roles in oceanic food webs and biogeochemical cycling. Despite the ecological significance of copepods, little is known regarding the causes of copepod mortality, and up to 35% of total copepod mortality cannot be accounted for by predation alone. Viruses have been established as ecologically important infectious agents in the oceans; however, viral infection has not been investigated in mesozooplankton communities. Here we used molecular and microscopic techniques to document viral infection in natural populations of the calanoid copepods Acartia tonsa (Dana) and Labidocera aestiva (Wheeler) in Tampa Bay, FL. Viral metagenomics revealed previously undocumented viruses in each species, named Acartia tonsa copepod circo-like virus (AtCopCV) and Labidocera aestiva copepod circo-like virus (LaCopCV). LaCopCV was found to be extremely prevalent and abundant in L. aestiva populations, with up to 100% prevalence in some samples and average viral loads of 1.13 × 105 copies per individual. LaCopCV transcription was also detected in the majority of L. aestiva individuals, indicating viral activity. AtCopCV was sporadically detected in A. tonsa populations year-round, suggesting temporal variability in viral infection dynamics. Finally, virus-like particles of unknown identity were observed in the connective tissues of A. tonsa and L. aestiva by transmission electron microscopy, demonstrating that viruses were actively proliferating in copepod connective tissue as opposed to infecting gut contents, parasites, or symbionts. Taken together, these results provide strong independent lines of evidence for active viral infection in dominant copepod species, indicating that viruses may significantly influence mesozooplankton ecology. PMID:23297243

Dunlap, Darren S.; Ng, Terry Fei Fan; Rosario, Karyna; Barbosa, Jorge G.; Greco, Anthony M.; Breitbart, Mya; Hewson, Ian

2013-01-01

38

Physical controls on copepod aggregations in the Gulf of Maine  

E-print Network

This thesis explores the role that the circulation in the Gulf of Maine (GOM) plays in determining the distribution of dense aggregations of copepods. These aggregations are an important part of the marine ecosystem, ...

Woods, Nicholas W

2013-01-01

39

Copepod hatching success in marine ecosystems with high diatom concentrations.  

PubMed

Diatoms dominate spring bloom phytoplankton assemblages in temperate waters and coastal upwelling regions of the global ocean. Copepods usually dominate the zooplankton in these regions and are the prey of many larval fish species. Recent laboratory studies suggest that diatoms may have a deleterious effect on the success of copepod egg hatching. These findings challenge the classical view of marine food-web energy flow from diatoms to fish by means of copepods. Egg mortality is an important factor in copepod population dynamics, thus, if diatoms have a deleterious in situ effect, paradoxically, high diatom abundance could limit secondary production. Therefore, the current understanding of energy transfer from primary production to fisheries in some of the most productive and economically important marine ecosystems may be seriously flawed. Here we present in situ estimates of copepod egg hatching success from twelve globally distributed areas, where diatoms dominate the phytoplankton assemblage. We did not observe a negative relationship between copepod egg hatching success and either diatom biomass or dominance in the microplankton in any of these regions. The classical model for diatom-dominated system remains valid. PMID:12353032

Irigoien, Xabier; Harris, Roger P; Verheye, Hans M; Joly, Pierre; Runge, Jeffrey; Starr, Michel; Pond, David; Campbell, Robert; Shreeve, Rachael; Ward, Peter; Smith, Amy N; Dam, Hans G; Peterson, William; Tirelli, Valentina; Koski, Marja; Smith, Tania; Harbour, Derek; Davidson, Russell

2002-09-26

40

Copepod Population-Specific Response to a Toxic Diatom Diet  

PubMed Central

Diatoms are key phytoplankton organisms and one of the main primary producers in aquatic ecosystems. However, many diatom species produce a series of secondary metabolites, collectively termed oxylipins, that disrupt development in the offspring of grazers, such as copepods, that feed on these unicellular algae. We hypothesized that different populations of copepods may deal differently with the same oxylipin-producing diatom diet. Here we provide comparative studies of expression level analyses of selected genes of interest for three Calanus helgolandicus populations (North Sea, Atlantic Ocean and Mediterranean Sea) exposed to the same strain of the oxylipin-producing diatom Skeletonema marinoi using as control algae the flagellate Rhodomonas baltica. Expression levels of detoxification enzymes and stress proteins (e.g. glutathione S-transferase, glutathione synthase, superoxide dismutase, catalase, aldehyde dehydrogenases and heat shock proteins) and proteins involved in apoptosis regulation and cell cycle progression were analyzed in copepods after both 24 and 48 hours of feeding on the diatom or on a control diet. Strong differences occurred among copepod populations, with the Mediterranean population of C. helgolandicus being more susceptible to the toxic diet compared to the others. This study opens new perspectives for understanding copepod population-specific responses to diatom toxins and may help in underpinning the cellular mechanisms underlying copepod toxicity during diatom blooms. PMID:23056617

Lauritano, Chiara; Carotenuto, Ylenia; Miralto, Antonio; Procaccini, Gabriele; Ianora, Adrianna

2012-01-01

41

Composition and community structure of zooplankton in the sea ice-covered western Weddell Sea in spring 2004—with emphasis on calanoid copepods  

NASA Astrophysics Data System (ADS)

The mesozooplankton community, with special emphasis on calanoid copepods, was studied with respect to its species composition, abundance, vertical distribution and developmental structure during the "Ice Station POLarstern" (ISPOL) expedition to the ice-covered western Weddell Sea. Stratified zooplankton tows were carried out nine times between 1 December 2004 and 2 January 2005 with a multiple opening-closing net between 0 and 1000 m depth. Copepods were by far the most abundant taxon, contributing more than 94% of the total mesozooplankton. Numerical dominants were cyclopoid copepods, mostly Oncaea spp. A total of 66 calanoid copepod species were identified, but the calanoid copepod community was characterised by the dominance of only a few species. The most numerous species was Microcalanus pygmaeus, which comprised on average 70% of all calanoids. Calanoides acutus and Metridia gerlachei represented other abundant calanoid species contributing an average of 8% and 7%, respectively. All other species comprised less than 3%. The temporal changes in the abundance and population structure of M. pygmaeus and M. gerlachei were small while a shift in the stage frequency distribution of C. acutus was observed during the study: copepodite stage IV (C IV) dominated the C. acutus population with 48-50% during the first week of December, while C V comprised 48% in late December. C I and C II of C. acutus were absent in the samples, and males occurred only in very low numbers in greater depths. In M. gerlachei, C I was not found, whereas all developmental stages of M. pygmaeus occurred throughout the study. All three species showed migratory behaviour, and they occurred in upper water layers towards the end of the investigation. This vertical ascent was most pronounced in C. acutus and relatively weak in the other two species. In M. pygmaeus and M. gerlachei, copepodids were responsible for the upward migration in late December, while the vertical distribution of adults did not change. In C. acutus, all abundant developmental stages (C IV, C V and females) ascended to upper water layers. Almost exclusively (93%) medium- and semi-ripe females of C. acutus and M. gerlachei were found, and only 3-4% of the ovaries were ripe. The absence of C I and the low number of ripe females indicate that the main reproductive period had not started in C. acutus and M. gerlachei until the end of our study in early January. In contrast, the high portion of C I and C II of M. pygmaeus suggests that reproduction of this species had started in October-November and hence before the onset of the phytoplankton bloom in the water. The community structure did not differ between stations with one exception on 26 December, when the station was strongly influenced by the continental shelf.

Schnack-Schiel, Sigrid B.; Michels, Jan; Mizdalski, Elke; Schodlok, Michael P.; Schröder, Michael

2008-04-01

42

Hydrocarbon Contamination Decreases Mating Success in a Marine Planktonic Copepod  

PubMed Central

The mating behavior and the mating success of copepods rely on chemoreception to locate and track a sexual partner. However, the potential impact of the water-soluble fraction of hydrocarbons on these aspects of copepod reproduction has never been tested despite the widely acknowledged acute chemosensory abilities of copepods. I examined whether three concentrations of the water-soluble fraction of diesel oil (0.01%, 0.1% and 1%) impacts (i) the swimming behavior of both adult males and females of the widespread calanoid copepod Temora longcornis, and (ii) the ability of males to locate, track and mate with females. The three concentrations of the water-soluble fraction of diesel oil (WSF) significantly and non-significantly affect female and male swimming velocities, respectively. In contrast, both the complexity of male and female swimming paths significantly decreased with increasing WSF concentrations, hence suggesting a sex-specific sensitivity to WSF contaminated seawater. In addition, the three WSF concentrations impacted both T. longicornis mating behavior and mating success. Specifically, the ability of males to detect female pheromone trails, to accurately follow trails and to successfully track a female significantly decreased with increasing WSF concentrations. This led to a significant decrease in contact and capture rates from control to WSF contaminated seawater. These results indicate that hydrocarbon contamination of seawater decreases the ability of male copepods to detect and track a female, hence suggest an overall impact on population fitness and dynamics. PMID:22053187

Seuront, Laurent

2011-01-01

43

Copepods associated with reef corals: a comparison between the Atlantic and the Pacific  

Microsoft Academic Search

Endoparasitic copepods are very numerous in Indo-West Pacific corals. In West Indian corals they were thought to be absent, but recent studies have shown that a varied endoparasitic copepod fauna exists as well. Striking is the taxonomic composition of the coral-inhabiting copepods:

Jan H. Stock

1988-01-01

44

Spatial heterogeneity of zooplankton abundance and diversity in the Saudi coastal waters of the Southern Red Sea  

NASA Astrophysics Data System (ADS)

The horizontal distribution, abundance and diversity of zooplankton has been studied at 50 stations along the Saudi coastal waters of the southern Red Sea (27 stations around Farasan archipelago, 9 around Al-Qunfodah and 14 around Al-Lith) during March-April 2011 using a plankton net of 150 µm. The zooplankton standing crop fluctuated between 1058 and 25787 individuals/m3 with an average of 5231 individuals/m3. Zooplankton was dominated by holoplanktonic forms that representing 80.26 % of total zooplankton, while meroplanktonic constituting 19.74% and dominated by mollusc larvae. Copepods appeared to be the predominant component, formed an average of 69.69 % of the total zooplankton count followed by chaetognaths and urochordates (4.5 and 4.1% of total zooplankton respectively). A total of 100 copepods species in addition to several species of other planktonic groups (cladocerans, chaetognaths, urochordates) were recorded in the study area. The copepod diversity decreased northward (94, 69 and 62 species at Farasan, Al-Qunfodah and Al-Lith respectively). In general, adult cyclopoid copepods dominated the zooplankton community in term of abundance and species number (19.55 %, 65 species) with dominance of Oncaea media, Oithona similis and Farranula carinata followed by adult calanoid copepods (19.38%, 35 species) with dominance of Paracalanus aculeatus, Clausocalanus minor, Acartia (Acanthacartia) fossae and Centropages orsinii. Harapacticoids densities were low in abundance, represented only by 5 species and dominated mainly by Euterpina acutifronis. Some copepod species decreased northward: Acartia amboinensis, Canthocalanus pauper, Labidocera acuta, Corycaeus flaccus, C. typicus, C. agilis, C. catus, C. giesbrechti, C. latus, C. furcifer and Euterpina acutifronis, while others increased northward (Acartia fossae, Undinula vulgaris and Centropages orsinii). Among copepod orders, Monstrilloida and Siphonostomatoida were observed only in southern area (Farasan archipelago). Keywords: Zooplankton, copepods, abundance, diversity, Red Sea, Saudi Arabia.

Al-Aidaroos, Ali; El-Sherbiny, Mohsen; Mantha, Gopikrishna

2013-04-01

45

Interactions between Benthic Copepods, Bacteria and Diatoms Promote Nitrogen Retention in Intertidal Marine Sediments  

PubMed Central

The present study aims at evaluating the impact of diatoms and copepods on microbial processes mediating nitrate removal in fine-grained intertidal sediments. More specifically, we studied the interactions between copepods, diatoms and bacteria in relation to their effects on nitrate reduction and denitrification. Microcosms containing defaunated marine sediments were subjected to different treatments: an excess of nitrate, copepods, diatoms (Navicula sp.), a combination of copepods and diatoms, and spent medium from copepods. The microcosms were incubated for seven and a half days, after which nutrient concentrations and denitrification potential were measured. Ammonium concentrations were highest in the treatments with copepods or their spent medium, whilst denitrification potential was lowest in these treatments, suggesting that copepods enhance dissimilatory nitrate reduction to ammonium over denitrification. We hypothesize that this is an indirect effect, by providing extra carbon for the bacterial community through the copepods' excretion products, thus changing the C/N ratio in favour of dissimilatory nitrate reduction. Diatoms alone had no effect on the nitrogen fluxes, but they did enhance the effect of copepods, possibly by influencing the quantity and quality of the copepods' excretion products. Our results show that small-scale biological interactions between bacteria, copepods and diatoms can have an important impact on denitrification and hence sediment nitrogen fluxes. PMID:25360602

Stock, Willem; Heylen, Kim; Sabbe, Koen; Willems, Anne; De Troch, Marleen

2014-01-01

46

Density-dependent mortality in an oceanic copepod population  

Microsoft Academic Search

Planktonic copepods are primary consumers in the ocean and are perhaps the most numerous metazoans on earth. Secondary production by these zooplankton supports most food webs of the open sea, directly affecting pelagic fish populations and the biological pump of carbon into the deep ocean. Models of marine ecosystems are quite sensitive to the formulation of the term for zooplankton

M. D. Ohman; H.-J. Hirche

2001-01-01

47

1999 Macmillan Magazines Ltd Copepods, the small planktonic crus-  

E-print Network

of the order Calanoida, which dominates planktonic communities and provides key links in marine food webs5. Although abun- dant, they are restricted in their distribution: the Arietelloidea are deep-sea forms-ocean planktonic commu- nities and also have representatives in coastal and deep-sea habitats. In copepods

Lenz, Petra H.

48

Complex trophic interactions of calanoid copepods in the Benguela upwelling system  

NASA Astrophysics Data System (ADS)

Life-cycle adaptations, dietary preferences and trophic levels of calanoid copepods from the northern Benguela Current off Namibia were determined via lipid classes, marker fatty acids and stable isotope analyses, respectively. Trophic levels of copepod species were compared to other zooplankton and top consumers. Lipid class analyses revealed that three of the dominant calanoid copepod species stored wax esters, four accumulated triacylglycerols and another three species were characterised by high phospholipid levels. The two biomarker approaches (via fatty acids and stable isotopes) revealed a complex pattern of trophic positions for the various copepod species, but also highlighted the dietary importance of diatoms and dinoflagellates. Calanoides carinatus and Nannocalanus minor occupied the lowest trophic level (predominantly herbivorous) corresponding to high amounts of fatty acid markers for diatoms (e.g. 16:1(n - 7)) and dinoflagellates (e.g. 18:4(n - 3)). These two copepod species represent the classical link between primary production and higher trophic levels. All other copepods belonged to secondary or even tertiary (some deep-sea copepods) consumers. The calanoid copepod species cover the entire range of ?15N ratios, as compared to ?15N ratios of all non-calanoid taxa investigated, from salps to adult fish. These data emphasise that the trophic roles of calanoid copepods are far more complex than just interlinking primary producers with pelagic fish, which should also be considered in the process of developing realistic food-web models of coastal upwelling systems.

Schukat, Anna; Auel, Holger; Teuber, Lena; Lahajnar, Niko; Hagen, Wilhelm

2014-01-01

49

Contrasting Ecosystem-Effects of Morphologically Similar Copepods  

PubMed Central

Organisms alter the biotic and abiotic conditions of ecosystems. They can modulate the availability of resources to other species (ecosystem engineering) and shape selection pressures on other organisms (niche construction). Very little is known about how the engineering effects of organisms vary among and within species, and, as a result, the ecosystem consequences of species diversification and phenotypic evolution are poorly understood. Here, using a common gardening experiment, we test whether morphologically similar species and populations of Diaptomidae copepods (Leptodiaptomus ashlandi, Hesperodiaptomus franciscanus, Skistodiaptomus oregonensis) have similar or different effects on the structure and function of freshwater ecosystems. We found that copepod species had contrasting effects on algal biomass, ammonium concentrations, and sedimentation rates, and that copepod populations had contrasting effects on prokaryote abundance, sedimentation rates, and gross primary productivity. The average size of ecosystem-effect contrasts between species was similar to those between populations, and was comparable to those between fish species and populations measured in previous common gardening experiments. Our results suggest that subtle morphological variation among and within species can cause multifarious and divergent ecosystem-effects. We conclude that using morphological trait variation to assess the functional similarity of organisms may underestimate the importance of species and population diversity for ecosystem functioning. PMID:22140432

Matthews, Blake; Hausch, Stephen; Winter, Christian; Suttle, Curtis A.; Shurin, Jonathan B.

2011-01-01

50

Cannibalistic behaviour of rock-pool copepods: An experimental approach for space, food and kinship  

Microsoft Academic Search

Studies on cannibalism in harpacticoid copepods are restricted to predation on naupliar larvae in rock-pool harpacticoids of the genus Tigriopus. An earlier experimental study on the Mediterranean copepod Tigriopus fulvus indicated that females recognized their own larvae and preferentially preyed on nauplii other than their own. In a series of laboratory experiments, we tested if there were differences in naupliar

Fabiane Gallucci; Emil Ólafsson

2007-01-01

51

COPEPOD PARASITES OF FRESH~WATER FISHES AND THEIR ECONOMIC RELATIONS TO MUSSEL GLOCHIDIA  

E-print Network

COPEPOD PARASITES OF FRESH~WATER FISHES AND THEIR ECONOMIC RELATIONS TO MUSSEL GLOCHIDIA By Charles PARASITES OF FRESH-WATER FISHES AND 1HEIR ECONOMIC RELATIONS TO MUSSEL GLOCHIDIA. J1. 'By CHARLES BRANCH, an extended examination was-made of the parasitic copepods which infest our fresh-water fishes

52

A FRESHWATER DIAPTOMID COPEPOD HARVESTED FOR HUMAN CONSUMPTION IN CENTRAL LAOS  

Microsoft Academic Search

During fish surveys in Laos in 1997, a small fishery for an unnamed copepod of the genus Allodiaptomus (Calanoida: Diaptomidae: Diaptominae) was discovered along the Xe Lanong. The copepods are harvested in man-made triangular shelters built in the river, along the shores and stored salted in bamboo tubes . The resource is apparently not rare as it is reported to

Maurice Kottelat

53

Rapid Jumps and Bioluminescence Elicited by Controlled Hydrodynamic Stimuli in a Mesopelagic Copepod, Pleuromamma xiphius  

Microsoft Academic Search

Actively vertically migrating mesopelagic copepods are preyed upon by a wide variety of fishes and invertebrates. Their responses to predatory attacks in- clude vigorous escape jumps and discharge of biolumi- nescent material. Escape jumps and bioluminescent dis- charges in the calanoid copepod Pleuromamma xiphias were elicited by quantified hydrodynamic disturbances. Brief weak stimuli (peak water velocity 64 ? 21 pm

D. K. HARTLINE; E. J. BUSKEY; P. H. LENZ

1999-01-01

54

Feeding habits of mesopelagic copepods in Sagami Bay: Insights from integrative analysis  

NASA Astrophysics Data System (ADS)

We investigated the feeding habits of mesopelagic copepods in Sagami Bay during a spring bloom, focusing on omnivorous copepods of the families Aetideidae, Metridinidae, Scolecitrichidae, and Spinocalanidae by integrative application of stable-isotope (SI) analysis, microscopic observation of gut contents, elemental analysis of gut contents and sinking particles with an electron probe micro analyzer (EPMA), and morphological analysis of mouthparts. The SI ratios (?13C and ?15N) of most mesopelagic species that initially were assumed to feed mainly on marine snow (sinking particles) were allocated within the SI plots that were assumed for the consumers of particulate organic matter from the epipelagic zone. Microscopy showed different compositions of gut contents among the copepods, most of which ingested marine snow containing incompletely degraded phytoplankton and cyanobacteria. According to the EPMA analysis, percentages of terrigenous mineral particles in marine snow were significantly higher than those in most of the copepod guts, suggesting selective ingestion of sinking particles by these copepods. Morphological analysis showed that mouthparts of most of the copepods were not suitable for fine-particle feeding. These mesopelagic copepods were distributed mostly below 50 m, where Chl-a was essentially depleted. These observations suggest feeding specialization among mesopelagic omnivorous copepods, as well as their selective ingestion of fresher particles and/or parts among diverse fractions of marine snow.

Sano, Masayoshi; Maki, Koh; Nishibe, Yuichiro; Nagata, Toshi; Nishida, Shuhei

2013-03-01

55

Nineteen trace elements in marine copepods collected from the coastal waters off northeastern Taiwan  

NASA Astrophysics Data System (ADS)

This study analyzed nineteen trace elements in marine copepods collected from the coastal waters off Northeastern Taiwan. The bioconcentration factors (BCF) of the analyzed elements in copepods are discussed. Owing to the upwelling intrusion of Kuroshio Water, the study area presented an enriched copepod community and the copepod abundance ranged within 106-4890 ind. m-3. The trace elements content in the analyzed copepods varied substantially, ranging from 0.01 to 780 mg kg-1. and the average concentration followed the sequence: Sr>Fe>Zn>Cr>Li>Ni>Mn>Ba>Cu>Se>As>V>Pb>Rb>Cd>Co>Ga>Ag>Cs. The trace elements can be divided into five groups according to the concentration quantity in copepods: (1) Sr; (2) Fe, Zn, Cr, Li and Ni; (3) Mn, Cu, Ba, Se, As, V, Pb and Rb; (4) Cd, Co and Ga; (5) Ag and Cs. The concentration difference in each group is nearly one order of magnitude. The trace element concentrations in copepods seem to be in proportion to the dissolved concentrations in seawater. The trace element log BCF values ranged within 1.32-5.66. Transition metals generally have a higher BCF value than the associated minor elements, such as Ba, Sr, Li and Rb. The trace element BCF value in copepods is in inverse proportion to the dissolved concentrations in seawater.

Fang, Tien-Hsi; Hsiao, Shih-Hui; Nan, Fan-Hua

2014-12-01

56

RESPONSES OF ZOOPLANKTON AND CHAOBORUS TO TEMEPHOS IN A NATURAL POND AND IN THE LABORATORY  

EPA Science Inventory

Application of the organophosphorus insecticide temephos to a natural pond in central Minnesota was followed by reduction within 24 hr in all cladocerans, in Diaptomus leptopus and in Chaoborus americanus, and increases in cyclopoid copepods, copepod nauplii and rotifer Keratella...

57

Probability Models for the Distribution of Copepods in Different Coastal Ecosystems Along the Straits of Malacca  

NASA Astrophysics Data System (ADS)

Copepods are the most abundant microcrustaceans in the marine waters and are the major food resource for many commercial fish species. In addition, changes in the distribution and population composition of copepods may also serve as an indicator of global climate changes. Therefore, it is important to model the copepod distribution in different ecosystems. Copepod samples were collected from three different ecosystems (seagrass area, cage aquaculture area and coastal waters off shrimp aquaculture farm) along the coastal waters of the Malacca Straits over a one year period. In this study the major statistical analysis consisted of fitting different probability models. This paper highlights the fitting of probability distributions and discusses the adequateness of the fitted models. The usefulness of these fitted models would enable one to make probability statements about the distribution of copepods in three different ecosystems.

Matias-Peralta, Hazel Monica; Ghodsi, Alireza; Shitan, Mahendran; Yusoff, Fatimah Md.

58

Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approach  

NASA Astrophysics Data System (ADS)

Combined in situ and laboratory studies were conducted to document the effects of anoxia on the structure and functioning of meiobenthic communities, with special focus on harpacticoid copepods. In a first step, anoxia was created artificially by means of an underwater chamber at 24 m depth in the Northern Adriatic, Gulf of Trieste (Mediterranean). Nematodes were found as most abundant taxon, followed by harpacticoid copepods. While nematode densities were not affected by treatment (anoxia/normoxia) or sediment depth, these factors had a significant impact on copepod abundances. Harpacticoid copepod family diversity, in contrast, was not affected by anoxic conditions, only by depth. Ectinosomatidae and Cletodidae were most abundant in both normoxic and anoxic samples. The functional response of harpacticoid copepods to anoxia was studied in a laboratory tracer experiment by adding 13C pre-labelled diatoms to sediment cores in order to test (1) if there is a difference in food uptake by copepods under normoxic and anoxic conditions and (2) whether initial (normoxia) feeding of harpacticoid copepods on diatoms results in a better survival of copepods in subsequent anoxic conditions. Independent of the addition of diatoms, there was a higher survival rate in normoxia than anoxia. The supply of additional food did not result in a higher survival rate of copepods in anoxia, which might be explained by the presence of a nutritionally better food source and/or a lack of starvation before adding the diatoms. However, there was a reduced grazing pressure by copepods on diatoms in anoxic conditions. This resulted in a modified fatty acid composition of the sediment. We concluded that anoxia not only impacts the survival of consumers (direct effect) but also of primary producers (indirect effect), with important implications for the recovery phase.

De Troch, M.; Roelofs, M.; Riedel, B.; Grego, M.

2013-02-01

59

Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approach  

NASA Astrophysics Data System (ADS)

Combined in situ and laboratory studies were conducted to document the effects of anoxia on the structure and functioning of meiobenthic communities, with special focus on harpacticoid copepods. In a first step, anoxia was created artificially by means of an underwater chamber at 24 m depth in the Northern Adriatic, Gulf of Trieste (Mediterranean). Nematodes were found as the most abundant taxon, followed by harpacticoid copepods. While nematode densities were not affected by treatment (anoxia/normoxia) or sediment depth, these factors had a significant impact on copepod abundances. Harpacticoid copepod family diversity, in contrast, was not affected by anoxic conditions, only by depth. Ectinosomatidae and Cletodidae were most abundant in both normoxic and anoxic samples. The functional response of harpacticoid copepods to anoxia was studied in a laboratory tracer experiment by adding 13C pre-labelled diatoms to sediment cores in order to test (1) if there is a difference in food uptake by copepods under normoxic and anoxic conditions and (2) whether initial (normoxia) feeding of harpacticoid copepods on diatoms results in a better survival of copepods in subsequent anoxic conditions. Independent of the addition of diatoms, there was a higher survival rate in normoxia than anoxia. The supply of additional food did not result in a higher survival rate of copepods in anoxia, which might be explained by the presence of a nutritionally better food source and/or a lack of starvation before adding the diatoms. However, there was a reduced grazing pressure by copepods on diatoms in anoxic conditions. This resulted in a modified fatty acid composition of the sediment. We concluded that anoxia not only impacts the survival of consumers (direct effect) but also of primary producers (indirect effect), with important implications for the recovery phase.

De Troch, M.; Roelofs, M.; Riedel, B.; Grego, M.

2013-06-01

60

Astaxanthin production in marine pelagic copepods grazing on two different phytoplankton diets  

NASA Astrophysics Data System (ADS)

The red carotenoid astaxanthin is a powerful natural antioxidant of great importance in aquatic food webs where it is abundant in eggs and body tissues of fish and crustaceans. Little is known about the impact of the phytoplankton diet on astaxanthin production in copepods, its major pelagic producers. We followed the transfer of carotenoids from phytoplankton to copepods in a mesocosm experiment on the northern Atlantic coast (Norway) and recorded the astaxanthin production in copepods. Wild copepods grazed on nutrient-manipulated phytoplankton blooms, which differed in community composition and nutrient status (nitrogen or silicate limitation). The copepod pigments consisted mainly of free astaxanthin and mono- and diesters of astaxanthin. We found no significant difference in astaxanthin production per copepod individual or per unit C depending on the phytoplankton community. However, in the mesocosms astaxanthin per unit C decreased compared with natural levels, probably through a lower demand for photoprotection by the copepods in the dense phytoplankton blooms. The total astaxanthin production per litre was higher in the silicate-limited mesocosms through increased copepod density. Pigment ratio comparisons suggested that the copepod diet here consisted more of diatoms than in the nitrogen-limited mesocosms. Silicate-saturated diatoms were less grazed, possibly because they could invest more in defence mechanisms against their predators. Our study suggests that the production of astaxanthin in aquatic systems can be affected by changes in nutrient dynamics mediated by phytoplankton community composition and copepod population growth. This bottom-up force may have implications for antioxidant protection at higher trophic levels in the food web.

Van Nieuwerburgh, Lies; Wänstrand, Ingrid; Liu, Jianguo; Snoeijs, Pauli

2005-02-01

61

Invertebrate predation on planktonic rotifers  

Microsoft Academic Search

Representatives from many taxa including the Protozoa, Cnidaria, Rotifera, Cladocera, Cyclopoida, Calanoida, Harpacticoida, Chaoboridae, and Mysidacea are reported to feed on rotifers. There are few good quantitative data on predation on rotifers by any of these taxa with two exceptions, Rotifera and Cyclopoida. The present review focuses on the dynamics of Cyclopoid copepod predation. Intense and selective cyclopoid copepod predation

Craig E. Williamson

1983-01-01

62

Paternal inheritance of the primary sex ratio in a copepod.  

PubMed

Uniparentally inherited genetic elements are under strong selection to manipulate sex determination in their host and shift the host sex ratio towards the transmitting sex. For any sex-ratio trait, lineage analysis and quantitative genetics are important tools for characterizing the mode of inheritance (biparental vs. maternal vs. paternal) thereby narrowing the field of possible sex-determining mechanisms (e.g. polygenic, sex chromosomes with meiotic drive, cytoplasmic microorganisms). The primary sex ratio of the harpacticoid copepod, Tigriopus californicus is often male-biased and is highly variable among full sib families. We found that this extra-binomial variation for the primary sex ratio is paternally but not maternally transmitted in T. californicus. Paternal transmission of the primary sex ratio has been well documented in the haplo-diploid hymenoptera but is relatively rare in diplo-diploid organisms. If the sex-ratio trait is paternally transmitted in other closely related harpacticoid copepods it would explain why male biased primary sex ratios are so common in this group. PMID:16135125

Voordouw, M J; Robinson, H E; Anholt, B R

2005-09-01

63

Assimilation and regeneration of trace elements by marine copepods  

USGS Publications Warehouse

Assimilation efficiencies (AE) of five trace elements (Am, Cd, Co, Se, and Zn) and carbon by neritic copepods (Acartia tonsa and Temora longicornis) feeding at different food concentrations and on different food types (diatoms, green algae, flagellates, dinoflagellates, and Fe oxides) were measured with radiotracer techniques. Food concentration had little influence on AEs of C, Cd, Co, and Se within a range of 16-800 ?? C liter-1. AEs of Am and Zn were highest at low food concentrations (16-56 ??g C liter-1) but remained relatively constant when food levels exceeded 160 ??g C liter-1. Different algal diets had no major influence on AEs, which generally were in the order Cd > Se > Zn > Co > Am. Metals (Cd, Co, and Zn) were assimilated from Fe oxides with 50% less efficiency than from algal cells. Element regeneration into the dissolved phase was a significant route for the release of ingested elements by copepods and increased with increased food concentration. Element regeneration rates for Cd, Se, and Zn were comparable to the regeneration rates of major nutrients such as P (30-70% daily). Retention half-times of elements in decomposing fecal pellets ranged from 10 d (Am). The efficient assimilation and regeneration of Cd, Se, and Zn can significantly lengthen the residence time of these elements in ocean surface waters.

Wang, W.-X.; Reinfelder, J.R.; Lee, B.-G.; Fisher, N.S.

1996-01-01

64

Copepod communities from surface and ground waters in the everglades, south Florida  

USGS Publications Warehouse

We studied species composition and individual abundance of copepods in the surficial aquifer northeast of Everglades National Park. We identified the spatial distribution of subsurface habitats by assessing the depth of the high porosity layers in the limestone along a canal system, and we used copepods to assess the exchange between surface water and ground water along canal banks, at levels in the wells where high porosity connections to the canals exist. Surface- and ground-water taxa were defined, and species composition was related to areal position, sampling depth, and time. Subsurface copepod communities were dominated by surface copepods that disperse into the aquifer following the groundwater seepage along canal L-31N. The similarities in species composition between wells along canal reaches, suggest that copepods mainly enter ground water horizontally along canals via active and passive dispersal. Thus, the copepod populations indicate continuous connections between surface- and ground waters. The most abundant species were Orthocyclops modestus, Arctodiaptomus floridanus, Mesocyclops edax, and Thermocyclops parvus, all known in literature from surface habitats; however, these species have been collected in ground water in ENP. Only two stygophiles were collected: Diacylcops nearcticus and Diacyclops crassicaudis brachycercus. Restoration of the Everglades ecosystem requires a mosaic of data to reveal a complete picture of this complex system. The use of copepods as indicators of seepage could be a tool in helping to assess the direction and the duration of surface and ground water exchange.

Bruno, M.C.; Cunningham, K.J.; Perry, S.A.

2003-01-01

65

Light Primes the Escape Response of the Calanoid Copepod, Calanus finmarchicus  

PubMed Central

The timing and magnitude of an escape reaction is often the determining factor governing a copepod’s success at avoiding predation. Copepods initiate rapid and directed escapes in response to fluid signals created by predators; however little is known about how copepods modulate their behavior in response to additional sensory input. This study investigates the effect of light level on the escape behavior of Calanus finmarchicus. A siphon flow was used to generate a consistent fluid signal and the behavioral threshold and magnitude of the escape response was quantified in the dark and in the light. The results show that C. finmarchicus initiated their escape reaction further from the siphon and traveled with greater speed in the light than in the dark. However, no difference was found in the escape distance. These results suggest that copepods use information derived from multiple sensory inputs to modulate the sensitivity and strength of the escape in response to an increase risk of predation. Population and IBM models that predict optimal vertical distributions of copepods in response to visual predators need to consider changes in the copepod's behavioral thresholds when predicting predation risk within the water column. PMID:22761834

Fields, David M.; Shema, Steven D.; Browman, Howard I.; Browne, Thomas Q.; Skiftesvik, Anne Berit

2012-01-01

66

Comparison of different DNA-extraction techniques to investigate the bacterial community of marine copepods  

NASA Astrophysics Data System (ADS)

Marine zooplanktic organisms, such as copepods, are usually associated with large numbers of bacteria. Some of these bacteria live attached to copepods’ exoskeleton, while others prevail in their intestine and faecal pellets. Until now, general conclusions concerning the identity of these bacteria are problematic since the majority of previous studies focused on cultivable bacteria only. Hence, to date little is known on whether copepod genera or species harbour distinct bacterial populations and about the nature of this association. To shed more light on these copepod/bacteria consortia, the focus of this study was the development and evaluation of a suitable approach to extract bacterial DNA from different North Sea copepod genera. Furthermore, the bacterial DNA was analysed by PCR-DGGE and subsequent sequencing of excised bands. The result of this work was an appropriate extraction method for batches of ten to one copepod specimens and offered first insights as to which bacteria are attached to the copepods Acartia sp . and Temora sp . from Helgoland Roads (German Bight) and a laboratory-grown Acartia tonsa culture. It revealed the prevalence of Alphaproteobacteria.

Brandt, Petra; Gerdts, Gunnar; Boersma, Maarten; Wiltshire, Karen H.; Wichels, Antje

2010-12-01

67

[Response of copepod community characteristics to environmental factors in the Backshore Wetland of Expo Garden, Shanghai].  

PubMed

The Backshore Wetland of Expo Garden was the emphasis of the World Expo construction project in Shanghai in 2010, China programming district. We carried out studies on the community structure and spatial-temporal variation of copepod from September 2009 to August 2010. Statistical Product and Service Solutions (SPSS) was used for relevant statistical analysis between physicochemical parameters and copepod standing crop. Canonical correspondence analysis (CCA) was applied to further explore the correlation between copepod species and environmental parameters using CANOCO 4.5. A total of 23 copepod species in 11 genera, 6 families were identified. 5 dominant species of copepod were recorded during the survey period. They were Eucyclops serrulatus, Thermocyclops taihokuensis, Mesocyclops leuckarti, Thermocyclops brevifurcatus and Microcyclops varicans. The annual mean density of copepod was (8.6 +/- 16.6) ind x L(-1) and the biomass was (0.083 6 +/- 0.143 1) mg x L(-1). The standing crop of copepod had its first peak in July, the second in October and the bottom in January. The highest trophic level was measured at Site 1, decreasing along the flowing direction of the water current, and the lowest level was found at Site 10. The Margelf index remained low in winter and spring, but was increased in summer and autumn. The community structure of copepod was analyzed in relation to water quality parameters by canonical correspondence analysis (CCA). Water temperature, pH, nitrate nitrogen, nitrite nitrogen, TN, TP and dissolved oxygen were strongly correlated with the copepod community structure. PMID:23323429

Chen, Li-Jing; Wu, Yan-Fang; Jing, Yu-Xiang; Wang, Cong; Zhang, Yin-Jiang

2012-11-01

68

Copepod assemblages in the northern South China Sea during inter-monsoon transition periods  

NASA Astrophysics Data System (ADS)

We investigated the influence of permanent oceanographic features in structuring copepod assemblages in the northern South China Sea during the inter-monsoon transition periods, spring and autumn. A total of 25 families, 48 genera and 88 species, were recorded, as well as a decrease in species richness along with the seasonal temperature decrease. We show that copepod assemblages are influenced by quasi-permanent oceanographic conditions governing the Northeastern South China Sea, i.e. China Coastal Current and the Kuroshio Current intrusion. This study provides a synoptic picture of the seasonal changes in the community structure of copepods during spring and autumn in the northern South China Sea.

Hwang, Jiang-Shiou; López-López, Lucía; Molinero, Juan Carlos; Tseng, Li-Chun; Chen, Qing-Chao; Hung, Jia-Jang

2014-02-01

69

Sex Conversion Induced by Hydrostatic Pressure in the Marine Copepod Tigriopus californicus.  

PubMed

High hydrostatic pressure applied to the naupliar larval stages of the marine copepod Tigriopus californicus converts some individuals that would have become males into females. The copepodid stages are not sensitive to pressureinduced conversion. PMID:17743973

Vacquier, V D; Belser, W L

1965-12-17

70

Crustaceans from bitumen clast in Carboniferous glacial diamictite extend fossil record of copepods.  

PubMed

Copepod crustaceans are extremely abundant but, because of their small size and fragility, they fossilize poorly. Their fossil record consists of one Cretaceous (c. 115?Ma) parasite and a few Miocene (c. 14?Ma) fossils. In this paper, we describe abundant crustacean fragments, including copepods, from a single bitumen clast in a glacial diamictite of late Carboniferous age (c. 303?Ma) from eastern Oman. Geochemistry identifies the source of the bitumen as an oilfield some 100-300?km to the southwest, which is consistent with an ice flow direction from glacial striae. The bitumen likely originated as an oil seep into a subglacial lake. This find extends the fossil record of copepods by some 188?Ma, and of free-living forms by 289?Ma. The copepods include evidence of the extant family Canthocamptidae, believed to have colonized fresh water in Pangaea during Carboniferous times. PMID:20975721

Selden, Paul A; Huys, Rony; Stephenson, Michael H; Heward, Alan P; Taylor, Paul N

2010-01-01

71

The endemic copepod Calanus pacificus californicus as a potential vector of white spot syndrome virus.  

PubMed

The susceptibility of the endemic copepod Calanus pacificus californicus to white spot syndrome virus (WSSV) was established by the temporal analysis of WSSV VP28 transcripts by quantitative real-time PCR (qRT-PCR). The copepods were collected from a shrimp pond located in Bahia de Kino Sonora, Mexico, and challenged per os with WSSV by a virus-phytoplankton adhesion route. Samples were collected at 0, 24, 48 and 84 h postinoculation (hpi). The VP28 transcripts were not detected at early stages (0 and 24 hpi); however, some transcript accumulation was observed at 48 hpi and gradually increased until 84 hpi. Thus, these results clearly show that the copepod C. pacificus californicus is susceptible to WSSV infection and that it may be a potential vector for the dispersal of WSSV. However, further studies are still needed to correlate the epidemiological outbreaks of WSSV with the presence of copepods in shrimp ponds. PMID:24895865

Mendoza-Cano, Fernando; Sánchez-Paz, Arturo; Terán-Díaz, Berenice; Galván-Alvarez, Diego; Encinas-García, Trinidad; Enríquez-Espinoza, Tania; Hernández-López, Jorge

2014-06-01

72

Heritability of sex tendency in a harpacticoid copepod, Tigriopus californicus.  

PubMed

Systems with genetic variation for the primary sex ratio are important for testing sex-ratio theory and for understanding how this variation is maintained. Evidence is presented for heritable variation of the primary sex ratio in the harpacticoid copepod Tigriopus californicus. Variation in the primary sex ratio among families cannot be accounted for by Mendelian segregation of sex chromosomes. The covariance in sex phenotype between full-sibling clutches and between mothers and offspring suggests that this variation has a polygenic basis. Averaged over four replicates, the full-sibling heritability of sex tendency is 0.13 +/- 0.040; and the mother-offspring heritability of sex tendency is 0.31 +/- 0.216. Genetic correlations in the sex phenotype across two temperature treatments indicate large genotype-by-temperature interactions. Future experiments need to distinguish between zygotic, parental, or cytoplasmic mechanisms of sex determination in T. californicus. PMID:12389720

Voordouw, Maarten J; Anholt, Bradley R

2002-09-01

73

Reaction times and force production during escape behavior of a calanoid copepod, Undinula vulgaris  

Microsoft Academic Search

Effective escape behavior contributes to the success of copepods in planktonic communities. The kinematics of escape were\\u000a studied in tethered Undinulavulgaris (Calanoida) by analyzing the timing and magnitude of their power strokes to a precisely controlled, sudden mechanical perturbation\\u000a in the surrounding water. Copepods responded with rapid swims to water velocities of 36 to 86??m s?1. Reaction times were under

P. H. Lenz; D. K. Hartline

1999-01-01

74

Substrate selection by demersal calanoid copepods in shallow waters of Galveston Bay, Texas  

E-print Network

SUBSTRATE SELECTION BY DEMERSAL CALANOID COPEPODS IN SHALLOW WATERS OF GALVESTON BAY, TEXAS. A Thesis by ERIC KINGSBURY BROWN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1986 Major Subject, : Biology SUBSTRATE SELECTION BY DEHERSAL CALANOID COPEPODS IN SHALLOW WATERS OF GALVESTON BAY, TEXAS. A Thesis by ERIC KINGSBURY BROWN Approved as to style and content by: E. Taisoo ark (Co...

Brown, Eric Kingsbury

2012-06-07

75

Antibiotic-induced change of bacterial communities associated with the copepod Nitocra spinipes.  

PubMed

Environmental pressures, such as physical factors, diet and contaminants may affect interactions between microbial symbionts and their multicellular hosts. Despite obvious relevance, effects of antimicrobial contaminants on host-symbiont relations in non-target aquatic organisms are largely unknown. We show that exposure to antibiotics had negative effects on survival and juvenile development of the copepod Nitocra spinipes and caused significant alterations in copepod-associated bacterial communities. The significant positive correlations between indices of copepod development and bacterial diversity indicate that disruption of the microflora was likely to be an important factor behind retarded juvenile development in the experimental animals. Moreover, as evidenced by ribotype distribution in the bacterial clone libraries, the exposure to antibiotics caused a shift in dominance from Betaproteobacteria to Cardinium bacteria; the latter have been shown to cause reproductive manipulations in various terrestrial arthropods. Thus, in addition to providing evidence that the antibiotic-induced perturbation of the microbial community associates with reductions in fitness-related traits of the host, this study is the first record of a copepod serving as a host for endosymbiotic Cardinium. Taken together, our results suggest that (1) antimicrobial substances and possibly other stressors can affect micobiome and symbiont-mediated interactions in copepods and other hosts, and (2) Cardinium endosymbionts may occur in other copepods and affect reproduction of their hosts. PMID:22427962

Edlund, Anna; Ek, Karin; Breitholtz, Magnus; Gorokhova, Elena

2012-01-01

76

Antibiotic-Induced Change of Bacterial Communities Associated with the Copepod Nitocra spinipes  

PubMed Central

Environmental pressures, such as physical factors, diet and contaminants may affect interactions between microbial symbionts and their multicellular hosts. Despite obvious relevance, effects of antimicrobial contaminants on host-symbiont relations in non-target aquatic organisms are largely unknown. We show that exposure to antibiotics had negative effects on survival and juvenile development of the copepod Nitocra spinipes and caused significant alterations in copepod-associated bacterial communities. The significant positive correlations between indices of copepod development and bacterial diversity indicate that disruption of the microflora was likely to be an important factor behind retarded juvenile development in the experimental animals. Moreover, as evidenced by ribotype distribution in the bacterial clone libraries, the exposure to antibiotics caused a shift in dominance from Betaproteobacteria to Cardinium bacteria; the latter have been shown to cause reproductive manipulations in various terrestrial arthropods. Thus, in addition to providing evidence that the antibiotic-induced perturbation of the microbial community associates with reductions in fitness-related traits of the host, this study is the first record of a copepod serving as a host for endosymbiotic Cardinium. Taken together, our results suggest that (1) antimicrobial substances and possibly other stressors can affect micobiome and symbiont-mediated interactions in copepods and other hosts, and (2) Cardinium endosymbionts may occur in other copepods and affect reproduction of their hosts. PMID:22427962

Edlund, Anna; Ek, Karin; Breitholtz, Magnus; Gorokhova, Elena

2012-01-01

77

Danger of zooplankton feeding: the fluid signal generated by ambush-feeding copepods  

PubMed Central

Zooplankton feed in any of three ways: they generate a feeding current while hovering, cruise through the water or are ambush feeders. Each mode generates different hydrodynamic disturbances and hence exposes the grazers differently to mechanosensory predators. Ambush feeders sink slowly and therefore perform occasional upward repositioning jumps. We quantified the fluid disturbance generated by repositioning jumps in a millimetre-sized copepod (Re ? 40). The kick of the swimming legs generates a viscous vortex ring in the wake; another ring of similar intensity but opposite rotation is formed around the decelerating copepod. A simple analytical model, that of an impulsive point force, properly describes the observed flow field as a function of the momentum of the copepod, including the translation of the vortex and its spatial extension and temporal decay. We show that the time-averaged fluid signal and the consequent predation risk is much less for an ambush-feeding than a cruising or hovering copepod for small individuals, while the reverse is true for individuals larger than about 1 mm. This makes inefficient ambush feeding feasible in small copepods, and is consistent with the observation that ambush-feeding copepods in the ocean are all small, while larger species invariably use hovering or cruising feeding strategies. PMID:20538648

Ki?rboe, Thomas; Jiang, Houshuo; Colin, Sean P.

2010-01-01

78

Danger of zooplankton feeding: the fluid signal generated by ambush-feeding copepods.  

PubMed

Zooplankton feed in any of three ways: they generate a feeding current while hovering, cruise through the water or are ambush feeders. Each mode generates different hydrodynamic disturbances and hence exposes the grazers differently to mechanosensory predators. Ambush feeders sink slowly and therefore perform occasional upward repositioning jumps. We quantified the fluid disturbance generated by repositioning jumps in a millimetre-sized copepod (Re ? 40). The kick of the swimming legs generates a viscous vortex ring in the wake; another ring of similar intensity but opposite rotation is formed around the decelerating copepod. A simple analytical model, that of an impulsive point force, properly describes the observed flow field as a function of the momentum of the copepod, including the translation of the vortex and its spatial extension and temporal decay. We show that the time-averaged fluid signal and the consequent predation risk is much less for an ambush-feeding than a cruising or hovering copepod for small individuals, while the reverse is true for individuals larger than about 1 mm. This makes inefficient ambush feeding feasible in small copepods, and is consistent with the observation that ambush-feeding copepods in the ocean are all small, while larger species invariably use hovering or cruising feeding strategies. PMID:20538648

Kiørboe, Thomas; Jiang, Houshuo; Colin, Sean P

2010-11-01

79

Effects of animal density, volume, and the use of 2D\\/3D recording on behavioral studies of copepods  

Microsoft Academic Search

Studies on the behavior of copepods require both an appropriate experimental design and the means to perform objectively verifiable\\u000a numerical analysis. Despite the growing number of publications on copepod behavior, it has been difficult to compare these\\u000a studies. In this study, we studied two species of copepods, Eurytemora affinis and Pseudodiaptomus annandalei, and employed recently developed scaling and non-scaling methodology

Gaël Dur; Sami Souissi; François Schmitt; François-Gaël Michalec; Mohamed-Sofiane Mahjoub; Jiang-Shiou Hwang

2011-01-01

80

Bloom-Forming Cyanobacteria Support Copepod Reproduction and Development in the Baltic Sea  

PubMed Central

It is commonly accepted that summer cyanobacterial blooms cannot be efficiently utilized by grazers due to low nutritional quality and production of toxins; however the evidence for such effects in situ is often contradictory. Using field and experimental observations on Baltic copepods and bloom-forming diazotrophic filamentous cyanobacteria, we show that cyanobacteria may in fact support zooplankton production during summer. To highlight this side of zooplankton-cyanobacteria interactions, we conducted: (1) a field survey investigating linkages between cyanobacteria, reproduction and growth indices in the copepod Acartia tonsa; (2) an experiment testing relationships between ingestion of the cyanobacterium Nodularia spumigena (measured by molecular diet analysis) and organismal responses (oxidative balance, reproduction and development) in the copepod A. bifilosa; and (3) an analysis of long term (1999–2009) data testing relationships between cyanobacteria and growth indices in nauplii of the copepods, Acartia spp. and Eurytemora affinis, in a coastal area of the northern Baltic proper. In the field survey, N. spumigena had positive effects on copepod egg production and egg viability, effectively increasing their viable egg production. By contrast, Aphanizomenon sp. showed a negative relationship with egg viability yet no significant effect on the viable egg production. In the experiment, ingestion of N. spumigena mixed with green algae Brachiomonas submarina had significant positive effects on copepod oxidative balance, egg viability and development of early nauplial stages, whereas egg production was negatively affected. Finally, the long term data analysis identified cyanobacteria as a significant positive predictor for the nauplial growth in Acartia spp. and E. affinis. Taken together, these results suggest that bloom forming diazotrophic cyanobacteria contribute to feeding and reproduction of zooplankton during summer and create a favorable growth environment for the copepod nauplii. PMID:25409500

Hogfors, Hedvig; Motwani, Nisha H.; Hajdu, Susanna; El-Shehawy, Rehab; Holmborn, Towe; Vehmaa, Anu; Engström-Öst, Jonna; Brutemark, Andreas; Gorokhova, Elena

2014-01-01

81

AN INTEGRATION OF COPEPOD-BASED BAFS, LIFECYCLE TOXICITY TESTING, AND ENDOCRINE DISRUPTION METHODOLOGIES FOR RAPID POPULATION-LEVEL RISK ASSESSMENT OF PERSISTENT BIOACCUMULATIVE TOXICANTS  

EPA Science Inventory

Extensive multi-generational microplate culturing (copepod hatching stage through two broods) experiments were completed with the POPs lindane, DDD and fipronil sulfide.  Identical tandem microplate experiments were run concurrently to yield sufficient copepod biomass for li...

82

Impacts of ontogenetically migrating copepods on downward carbon flux in the western subarctic Pacific Ocean  

NASA Astrophysics Data System (ADS)

To evaluate the impacts of ontogenetically (seasonally) migrating copepods on carbon transport to the mesopelagic zone, we investigated depth distribution, population structure, and feeding activity of the ontogentic copepod community in the western subarctic Pacific Ocean from day-night pairs of zooplankton samples down to 1000 m during the VERtical Transport In the Global Ocean (VERTIGO) program. Over the 31 July-16 August 2005 study period, the biomass of Neocalanus cristatus and Neocalanus plumchrus predominated in the near surface waters, while Neocalanus flemingeri was already dormant at depth. We observed a strong diel migration for Metridia pacifica, and a seasonal downward migration for Eucalanus bungii. Based on gut pigment analysis, ingestion rate of the copepod community was 214-375 mg C m -2 day -1, which was equal to 26-37% of the concurrent primary production. However, comparison of grazing estimated from gut pigments to calculated carbon demand of the copepod community indicates that phytoplankton comprised 37-59% of the ingested carbon. Thus, the copepod community appears to have also relied on detritus and microzooplankton for their nutrition, likely because primary production during this time was dominated by picophytoplankton too small to be grazed by these large copepods. Fecal pellet flux by the copepod community was estimated to account for 141-223% of the sedimentary particulate organic carbon (POC) flux at 150 m, suggesting considerable fragmentation and consumption of pellets in the upper layers. Fecal pellets alone were adequate to meet copepod carbon demand in the surface 0-150 m layer. Active carbon flux by diel migration of M. pacifica (respiration, egestion, and mortality) was 4-17 mg C m -2 day -1, equal to 6-44% of sedimentary POC flux at 150 m. Active carbon flux by N. flemingeri ontogenetic migration (i.e., respiration and mortality at depth) contributed 246 mg C m -2 year -1, equal to 9% of sedimentary POC flux at 1000 m. The imminent downward migration of N. cristatus and N. plumchrus would lead to an additional ontogenetic carbon flux on the order of 1719 mg C m -2 year -1. Copepod fecal pellet transport and active transport by diel and ontogenetic migration are thus important carbon fluxes during a season dominated by small phytoplankton, and ontogenetic migrants in the subarctic Pacific Ocean play a relatively more important role in active carbon flux compared with other open-ocean regions.

Kobari, Toru; Steinberg, Deborah K.; Ueda, Ai; Tsuda, Atsushi; Silver, Mary W.; Kitamura, Minoru

2008-07-01

83

Density-dependent mortality in an oceanic copepod population.  

PubMed

Planktonic copepods are primary consumers in the ocean and are perhaps the most numerous metazoans on earth. Secondary production by these zooplankton supports most food webs of the open sea, directly affecting pelagic fish populations and the biological pump of carbon into the deep ocean. Models of marine ecosystems are quite sensitive to the formulation of the term for zooplankton mortality, although there are few data available to constrain mortality rates in such models. Here we present the first evidence for nonlinear, density-dependent mortality rates of open-ocean zooplankton. A high-frequency time series reveals that per capita mortality rates of eggs of Calanus finmarchicus Gunnerus are a function of the abundance of adult females and juveniles. The temporal dynamics of zooplankton populations can be influenced as much by time-dependent mortality rates as by variations in 'bottom up' forcing. The functional form and rates chosen for zooplankton mortality in ecosystem models can alter the balance of pelagic ecosystems, modify elemental fluxes into the ocean's interior, and modulate interannual variability in pelagic ecosystems. PMID:11493921

Ohman, M D; Hirche, H J

2001-08-01

84

Trampling on coral reefs: tourism effects on harpacticoid copepods  

NASA Astrophysics Data System (ADS)

Human trampling is a common type of disturbance associated with outdoor recreational activities in coastal ecosystems. In this study, the effect of trampling on the meiofaunal harpacticoid copepod assemblage inhabiting turfs on a coral reef was investigated. In Porto de Galinhas, northeastern Brazil, reef formations near the beach are one of the main touristic destinations in the country. To assess trampling impact, two areas were compared: a protected area and an area subject to intensive tourism. Densities of total Harpacticoida and of the most abundant harpacticoid species showed strong reductions in the trampled area. An analysis of covariance revealed that the loss of phytal habitat was not the main source of density reductions, showing that trampling affected the animals directly. In addition, multivariate analysis demonstrated differences in the structure of harpacticoid assemblages between areas. Of the 43 species identified, 12 were detected by the Indicator Species Analyses as being indicators of the protected or trampled areas. Moreover, species richness was reduced in the area open to tourism. At least 25 harpacticoids are new species for science, of these, 20 were more abundant or occurred only in the protected area, while five were more abundant or occurred only in the trampled area; thus, our results highlight the possibility of local extinction of still-unknown species as one of the potential consequences of trampling on coral reefs.

Sarmento, V. C.; Santos, P. J. P.

2012-03-01

85

The effect of Fucus vesiculosus on the grazing of harpacticoid copepods on diatom biofilms  

NASA Astrophysics Data System (ADS)

The effect of Fucus vesiculosus on the functional traits of three harpacticoid copepod species ( Tigriopus brevicornis, Paramphiascella fulvofasciata and Microarthridion littorale) was studied. These copepods are likely to be important grazers on biofilms consisting mainly of diatoms. Several microcosms were created using diatom cultures ( Navicula phyllepta and Seminavis robusta) and vegetative thalli of Fucus, with the biofilm associated, collected from the field. The diatoms were enriched in the stable carbon 13C to facilitate tracing in the harpacticoids. The biofilm on the Fucus was labeled through impregnation of the Fucus leaves in 13C enriched seawater. In all treatments a measurable uptake of diatoms was found for the three copepod species. All copepods showed a low uptake of labeled material when only Fucus thalli were available. The grazing on the benthic diatoms was negatively affected by the presence of the Fucus thalli in the case of P. fulvofasciata. One species, T. brevicornis, grazed efficiently both on sedimentary and epiphytic biofilms. We hereby proved experimentally that benthic harpacticoid copepods are able to switch their food uptake under different habitat/food circumstances. This variety of food uptake is an illustration of the so-called 'niche complementarity effect' that lies at the basis of diverse communities.

De Troch, M.; Chepurnov, V. A.; Vincx, M.; Ólafsson, E.

2008-10-01

86

Modelling physico-chemical factors affecting occurrences of a non-indigenous planktonic copepod in northeast Pacific estuaries  

Microsoft Academic Search

Estuarine ecosystems along the Pacific coast of North America are vulnerable to invasions by non-indigenous planktonic copepods, with docu- mented invasions by at least nine species introduced via ship's ballast. One of these, the calanoid copepod Pseudodiaptomus inopinus, now occurs in a relatively wide geographical area in coastal estuaries of Wash- ington and Oregon States. Although it appears to be

Jeffery R. Cordell; Lucinda M. Tear; Stephen M. Bollens

2009-01-01

87

SWIMMING PATTERN AS AN INDICATOR OF THE ROLES OF COPEPOD SENSORY SYSTEMS IN THE RECOGNITION OF FOOD  

EPA Science Inventory

The roles of copepod sensory systems in the recognition of food were investigated using the 'Bugwatcher', a video-computer system designed to track and describe quantitatively the swimming patterns of aquatic organisms. Copepods acclimated, or non-acclimated to a chemosensory sti...

88

Patch sizes and spatial patterns of meiobenthic copepods and benthic microalgae in sandy sediments: a microscale approach  

NASA Astrophysics Data System (ADS)

Meiobenthic copepods and benthic microalgae exhibit patchiness at centimetre scales. Recent studies have related the distribution of meiobenthic copepods to a primary food resource, benthic microalgae, using spatial auto-correlation procedures. However, these studies have only examined the copepod-microalgae spatial relationships in soft and relatively silty sediments. The purpose of this study was to determine the microscale distribution and patch sizes of copepods and microalgae in the relatively sandy (median grain size 2.90?; 7.6% silt and clay), intertidal sediments of Barnstable Harbor, Massachusetts, USA. Samples were collected at three sites using an array of 96 cores covering a 180.5 cm 2 area. Non-parametric statistical analyses proved to be inapplicable in this kind of study since they revealed no significant correlations between microalgal biomass and copepod abundances. However, microalgae and most copepods ( Microarthridion littorale, Nannopus palustris, and Coullana canadensis) were spatially auto-correlated and exhibited patchy distributions. Patch sizes for copepods ranged from 7 to 121 cm 2 while microalgal patches ranged from 30 to 191 cm 2. Patch sizes measured in this study are larger than previously reported for meiobenthic copepods and microalgae, suggesting that fine-sand habitats may promote larger patches than silty, muddy sediments.

Sandulli, R.; Pinckney, J.

1999-05-01

89

A new incubation system for the measurement of copepod egg production and egg hatching success in the field  

Microsoft Academic Search

The design and testing of an incubation system for studying copepod egg production and hatching success that allows undisturbed incubation and monitoring of eggs under field conditions for extended periods of time is described. The incubation system was tested with copepods from polar (Weddell Sea), temperate (Irish Sea) and subtropical (Atlantic Coast, Gulf of Mexico and Gulf Stream) seas between

C. A Burkart; G. S Kleppel

1998-01-01

90

The Role of Sensory Physiology and Behavior in the Remote Detection of Large Particles by Calanoid Copepods  

E-print Network

a body length away and were attacked after the "bow wake" of the moving copepod displaced the bead away beads outside of the influence of the copepod feeding current. The beads were frequently more than half its mechanosensors on the antennae to detect the bead, we constructed a physical model that showed

91

Experimental studies on the development of Contracaecum rudolphii (Nematoda: Anisakidae) in copepod and fish paratenic hosts.  

PubMed

The larval development of the nematode Contracaecum rudolphii (Rudolphi, 1819), a common parasite of the proventriculus of cormorants, was experimentally studied. Within the eggs cultivated in freshwater under laboratory temperatures of 20-22 degrees C, the developing larva undergoes two moults on days 4-5, attaining the third larval stage. Most of the ensheathed third-stage larvae, 291-457 microm long, hatch spontaneously from egg shells on days 5-6. Experiments have indicated that hatched ensheated third-stage larvae and those still inside egg capsules are already infective to copepods and fishes, which both can be considered paratenic (meta-paratenic) hosts. Five copepod species, Acanthocyclops vernalis, Cyclops strenuus, Ectocyclops phaleratus, Eucyclops serrulatus and Megacyclops viridis, the isopod Asellus aquaticus and small carps Cyprinus carpio were infected by feeding them these larvae. In addition, 9 fish species, Alburnoides bipunctatus, Anguilla anguilla, Barbatula barbatula, Cyprinus carpio, Gobio gobio, Perca fluviatilis, Phoxinus phoxinus, Poecilia reticulata and Tinca tinca, were successfully infected by feeding them copepods previously infected with C. rudolphii third-stage larvae. In fishes, larvae from copepods penetrate through the intestinal wall to the body cavity, where, in a few weeks, they become encapsulated; the larvae substantially grow in fish, attaining the body length up to 4.87 mm. In carp fry, the nematode third-stage larvae survived for about 15 months (up to 18 months in fish infected directly, i.e., without copepods). One small cormorant (Phalacrocorax carbo sinensis) was successfully infected by feeding it with copepods harbouring C. rudolphii third-stage larvae. PMID:19827362

Moravec, Frantisek

2009-09-01

92

Contrasting patterns of MAAs accumulation in two populations of the copepod Boeckella gracilipes.  

PubMed

The bio-accumulation of mycosporine-like amino acids (MAAs) is common in planktonic copepods that inhabit environments exposed to high levels of solar radiation. MAAs accumulation in copepods can be affected both by extrinsic (environmental) and intrinsic factors (local adaptation, genotype, etc.). Laboratory experiments were performed to study the bio-accumulation of MAAs in two geographically-isolated populations of Boeckella gracilipes from a mountain and a piedmont lake of North Patagonia. We performed two series of 10-day incubations of B. gracilipes from the different lakes applying two radiation conditions (PAR + UVR and darkness), at five different temperatures (5 to 20 °C) and providing a MAA-free flagellate as food. We assumed that differences in final MAAs concentrations between copepod populations should be exclusively due to environmental factors, and that any difference in the patterns of MAAs accumulation should exclusively arise from differences in MAAs concentration at the time of collection. MAAs concentration was three fold higher in B. gracilipes from Lake Verde than in copepods from the Lake Morenito. The MAAs suite was dominated (?90%) by a combination of porphyra-334 and mycosporine-glycine in copepods from Lake Verde, and porphyra-334 and MAA-332 in those from Lake Morenito. Two exclusive MAA compounds were identified, mycosporine-glycine in copepods from Lake Verde and shinorine in the copepod population from Lake Morenito. Laboratory experiments showed that: (i) exposure to PAR + UVR stimulated the accumulation of MAAs in both copepod populations; (ii) temperature affected the response of MAAs and, remarkably, low temperatures stimulated MAAs accumulation even in dark incubations, (iii) the response to radiation and temperature in MAAs accumulation was more pronounced in the population with low initial MAAs than in the population with high initial MAAs concentrations. The differences in intrinsic factors between B. gracilipes populations, such as local adaptation to contrasting UV and temperature scenarios, among others, appear to play an important role in determining levels and patterns of MAAs accumulation in B. gracilipes. PMID:24715094

Garcia, Patricia E; Ferraro, Marcela A; Perez, A Patricia; Zagarese, Horacio E; Dieguez, Maria C

2014-06-01

93

Four new xarifiid copepods (Poecilostomatoida) associated with the scleractinian coral Pavona explanulata (Lamarck) from off Taiwan.  

PubMed

Four new xarifiid copepods are described. They were found in association with the scleractinian coral Pavona explanulata (Lamarck) occurring in shallow water reefs off Yenliao in northern Taiwan. The four species are: Xarifia capillata n. sp., X. parva n. sp., X. pavonae n. sp. and X. taiwanensis n. sp. They were found together in a single washing of the host coral. Previously, 13 species of copepods have been found in association with nine species of Pavona Lamarck. More than half (7/13) of these symbionts are members of Xarifia Humes, 1960. PMID:21643899

Cheng, Yu-Rong; Ho, Ju-shey; Dai, Chang-Feng

2011-07-01

94

Life cycle strategy of the Antarctic calanoid copepod Stephos longipes  

NASA Astrophysics Data System (ADS)

Studies on the life strategy of the small calanoid copepod Stephos longipes were carried out in the eastern Weddell Sea during four expeditions (January/February 1985, August 1986, October/December 1986 and April/May 1992). Samples were taken from the water column, the ice/water interface and the sea ice. In winter (August 1986) S. longipes copepodite stage CIV occurred mainly in the upper water layers of the ice covered eastern Weddell Sea, while only nauplii were found in the sea ice. In late winter/early spring (October-December 1986) very low numbers of S. longipes were found in the water column, mainly in the upper 50m, but high numbers occurred immediately below and within the sea ice. Adults dominated in the water column and in the under ice water layer while the sea ice contained nauplii and copepodite stage CI. During summer (January/February 1985) the eastern Weddell Sea was almost entirely free of ice with the exception of fast ice fields atthe ice shelf. During this time S. longipes was concentrated in the upper 50m of the water column and in the ice/water interface where an ice cover was present. Young copepodite stages (CI-CIII) comprised the largest fraction of the population. In autumn (April/May 1992) as new ice began to develop, S. longipes, dominated by copepodite stage CIV, occurred in greatest number within mid-water layers. The abundance of S. longipes in autumn was similar to late winter/early spring highest in the sea ice and lowest in the water column. During all periods of investigation the population structure differed between the various habitats with the youngest population occurring in the sea ice and the oldest in the water column. A younger generation of the S. longipes population appears to overwinter in the sea ice and ice/water interface and an older one in deeper water layers or near the bottom.

Schnack-Schiel, Sigrid B.; Thomas, David; Dieckmann, Gerhard S.; Eicken, Hajo; Gradinger, Rolf; Spindler, Michael; Weissenberger, Jürgen; Mizdalski, Elke; Beyer, Kerstin

95

Prevalent Ciliate Symbiosis on Copepods: High Genetic Diversity and Wide Distribution Detected Using Small Subunit Ribosomal RNA Gene  

PubMed Central

Toward understanding the genetic diversity and distribution of copepod-associated symbiotic ciliates and the evolutionary relationships with their hosts in the marine environment, we developed a small subunit ribosomal RNA gene (18S rDNA)-based molecular method and investigated the genetic diversity and genotype distribution of the symbiotic ciliates on copepods. Of the 10 copepod species representing six families collected from six locations of Pacific and Atlantic Oceans, 9 were found to harbor ciliate symbionts. Phylogenetic analysis of the 391 ciliate 18S rDNA sequences obtained revealed seven groups (ribogroups), six (containing 99% of all the sequences) belonging to subclass Apostomatida, the other clustered with peritrich ciliate Vorticella gracilis. Among the Apostomatida groups, Group III were essentially identical to Vampyrophrya pelagica, and the other five groups represented the undocumented ciliates that were close to Vampyrophrya/Gymnodinioides/Hyalophysa. Group VI ciliates were found in all copepod species but one (Calanus sinicus), and were most abundant among all ciliate sequences obtained, indicating that they are the dominant symbiotic ciliates universally associated with copepods. In contrast, some ciliate sequences were found only in some of the copepods examined, suggesting the host selectivity and geographic differentiation of ciliates, which requires further verification by more extensive sampling. Our results reveal the wide occurrence and high genetic diversity of symbiotic ciliates on marine copepods and highlight the need to systematically investigate the host- and geography-based genetic differentiation and ecological roles of these ciliates globally. PMID:23024768

Guo, Zhiling; Liu, Sheng; Hu, Simin; Li, Tao; Huang, Yousong; Liu, Guangxing; Zhang, Huan; Lin, Senjie

2012-01-01

96

Accumulation of Polyunsaturated Aldehydes in the Gonads of the Copepod Acartia tonsa Revealed by Tailored Fluorescent Probes  

PubMed Central

Polyunsaturated aldehydes (PUAs) are released by several diatom species during predation. Besides other attributed activities, these oxylipins can interfere with the reproduction of copepods, important predators of diatoms. While intensive research has been carried out to document the effects of PUAs on copepod reproduction, little is known about the underlying mechanistic aspects of PUA action. Especially PUA uptake and accumulation in copepods has not been addressed to date. To investigate how PUAs are taken up and interfere with the reproduction in copepods we developed a fluorescent probe containing the ?,?,?,?-unsaturated aldehyde structure element that is essential for the activity of PUAs as well as a set of control probes. We developed incubation and monitoring procedures for adult females of the calanoid copepod Acartia tonsa and show that the PUA derived fluorescent molecular probe selectively accumulates in the gonads of this copepod. In contrast, a saturated aldehyde derived probe of an inactive parent molecule was enriched in the lipid sac. This leads to a model for PUAs' teratogenic mode of action involving accumulation and covalent interaction with nucleophilic moieties in the copepod reproductive tissue. The teratogenic effect of PUAs can therefore be explained by a selective targeting of the molecules into the reproductive tissue of the herbivores, while more lipophilic but otherwise strongly related structures end up in lipid bodies. PMID:25383890

Wolfram, Stefanie; Nejstgaard, Jens C.; Pohnert, Georg

2014-01-01

97

A new copepod with transformed body plan and unique phylogenetic position parasitic in the acorn worm Ptychodera flava.  

PubMed

Symbiotic copepods compose one-third of the known copepod species and are associated with a wide range of animal groups. Two parasitic copepods endoparasitic in acorn worms (Hemichordata), Ive balanoglossi and Ubius hilli, collected in the Mediterranean Sea and Australian waters, respectively, were described a century ago. Here we report a new parasitic copepod species, Ive ptychoderae sp. nov., found in Ptychodera flava, a widespread acorn worm in the Indo-Pacific Ocean and an emerging organism for developmental and evolutionary studies. The female of I. ptychoderae is characterized by having a reduced maxilliped and five pairs of annular swellings along the body that are morphologically similar but distinguishable from those in the two previously described parasitic copepods in acorn worms. Phylogenetic analysis based on the 18S rDNA sequence shows that I. ptychoderae may belong to Poecilostomatoida but represent a new family, which we name Iveidae fam. nov. Ive ptychoderae is commonly found in the acorn worm population with an average prevalence of 42% during the collecting period. The infection of the parasite induces the formation of cysts and causes localized lesions of the host tissues, suggesting that it may have negative effects on its host. Interestingly, most cysts contain a single female with one or multiple male copepods, suggesting that their sex determination may be controlled by environmental conditions. The relationships between the parasitic copepods and acorn worms thus provide a platform for understanding physiological and ecological influences and coevolution between parasites and hosts. PMID:24648208

Tung, Che-Huang; Cheng, Yu-Rong; Lin, Ching-Yi; Ho, Ju-Shey; Kuo, Chih-Horng; Yu, Jr-Kai; Su, Yi-Hsien

2014-02-01

98

Histopathology of a mesoparasitic hatschekiid copepod in hospite: does Mihbaicola sakamakii (Copepoda: Siphonostomatoida: Hatschekiidae) fast within the host fish tissue?  

PubMed

Mihbaicola sakamakii is a mesoparasitic copepod that infests the branchiostegal membranes of groupers (Perciformes: Serranidae). In this study, we observed M. sakamakii within host tissue. Histologically, copepods were found enclosed inside a pouch composed of the thickened epidermis of the host, tightly encased on all sides by the host epidermal pouch wall. There were no host blood cells or other food resources in the pouch lumen. Since the host epidermis was intact and continuous, even in the vicinity of the oral region of the parasite, the copepod would not have access to the host blood in this state. However, the stomach (ampullary part of the mid gut) was filled with granular components, the majority of which were crystalloids that likely originated from fish erythrocyte hemoglobin. We supposed that the parasite drinks blood exuded from the lesion in the fish caused by copepod entry into the host tissue. Invasion of the parasite may elicit immune responses in the host, but there were no traces on the copepod of any cellular immune reactions, such as encapsulation. The array of minute protuberances on the copepod cuticle surface may be involved in avoidance of cell adhesion. After the lesion has healed, the copepod is enclosed in a tough epidermal pouch, in which it gradually digests the contents of its stomach and continues egg production. PMID:25088597

Hirose, Euichi; Uyeno, Daisuke

2014-08-01

99

Meningeal-like Organization of Neural Tissues in Calanoid Copepods (Crustacea)  

E-print Network

Meningeal-like Organization of Neural Tissues in Calanoid Copepods (Crustacea) Frederic Mercier'i 96822 ABSTRACT Meninges, the connective tissue of the vertebrate cen- tral nervous system (CNS), have of the typical cells of vertebrate meninges and of their peripheral nervous system (PNS) connective tis- sue

Hartline, Daniel K.

100

In situ grazing rate of the copepod population in the western subarctic North Pacific during spring  

Microsoft Academic Search

Time series sampling with a multi-layer plankton sampler was carried out in the western subarctic North Pacific during spring 1991. Neocalanus cristatus, N. flemingeri and Eucalanus bungii dominated and accounted for 88.5% of the copepod population in volume. Neocalanus spp. were distributed in the upper mixed layer, while E. bungii was mainly distributed between 120 and 300 m throughout the

A. Tsuda; H. Sugisaki

1994-01-01

101

Biochemical responses of the copepod Centropages tenuiremis to CO(2)-driven acidified seawater.  

PubMed

An ecophysiological experiment was conducted to examine the biochemical effects of acidified seawater containing elevated concentration of CO(2) (C(CO2) 0.08, 0.20, 0.50 and 1.00%) on the copepod Centropages tenuiremis. AchE, ATPase, SOD, GPx, GST, GSH level and GSH/GSSG ratio of the copepod were analyzed. The results showed that elevated C(CO2) and the duration of culture time significantly influenced several biochemical indices in C. tenuiremis (ATPase, GPx, GST, GSH and SOD). Furthermore, the principal component analysis results indicated that 72.32% of the overall variance was explained by the first three principal components (GPx, SOD and GSH). Changes in GPx and GSH levels may play a significant role in the antioxidant defense of copepods against seawater acidification. The long-term response of copepods to seawater acidification and the synergistic effects of acidification with other environmental factors, such as temperature, salinity and trace metal need further investigation. PMID:22173405

Zhang, Dajuan; Li, Shaojing; Wang, Guizhong; Guo, Donghui; Xing, Kezhi; Zhang, Shulin

2012-01-01

102

Effects of cupric and zinc ion activities on the survival and reproduction of marine copepods  

Microsoft Academic Search

The toxicity of copper and zinc to the estuarine copepod Acartia tonsa and to the two diatom food species Thalassiosira pseudonana and T. weissflogii was measured in nitrilotriacetate-trace metal ion buffer systems at 25‰ S. Overall, A. tonsa appeared to be more sensitive to cupric and zinc ion activity than either of the diatoms; however, its sensitivity varied among the

W. G. Sunda; P. A. Tester; S. A. Huntsman

1987-01-01

103

Relationship between specific dynamic action and protein deposition in calanoid copepods  

Microsoft Academic Search

The link between specific dynamic action (SDA) and protein deposition was investigated in copepodites stage V of two calanoid copepod species, the neritic Acartia tonsa and the oceanic Calanus finmarchicus. This was done by measuring respiration before, during, and after a specific feeding period and measuring the incorporation of carbon into proteins. These were also measured on individuals incubated with

Peter Thor

2000-01-01

104

Meiofauna winners and losers of coastal hypoxia: case study harpacticoid copepods  

NASA Astrophysics Data System (ADS)

The impact of anoxia on meiobenthic copepod species was assessed by means of a field experiment. Four plexiglass chambers were deployed in situ in 24 m depth to simulate an anoxic event of 9 days, 1 month, 2 months and 10 months. From normoxic to anoxic conditions, we recorded a drop in copepod density and species richness. With increasing duration of anoxia the relative abundance of the individuals of the family Cletodidae increased, and they survived the 1 month and 2 month anoxia, the latter with few specimens. They were the true "winners" of the experimentally induced anoxia. Dominance did not increase in the deployments because not one, but several species from this family were tolerant to anoxia. The overall rate of survival was the same for males and females, but no juvenile stages of copepods survived in anoxia. During a recovery phase of 7 days after a short-term anoxia of 9 days, harpacticoid copepod density did not increase significantly, and there was only a slight increase in species diversity. We concluded that no substantial colonisation from the surrounding sediment took place. The survivors, however, showed a high potential for recovery according to the number of gravid females, whose number increased significantly once the oxygen was available again. These findings imply that substantial energy is allocated to reproduction in the recovery phase.

Grego, M.; Riedel, B.; Stachowitsch, M.; De Troch, M.

2014-01-01

105

Meiofauna winners and losers of coastal hypoxia: case study harpacticoid copepods  

NASA Astrophysics Data System (ADS)

The impact of anoxia on meiobenthic copepod species was assessed by means of a field experiment. Four plexiglass chambers were deployed in situ in 24 m depth to simulate an anoxic event of 9 days, 1 month, 2 months and 10 months. From normoxic to anoxic conditions, we recorded a drop in copepod density and species richness. With increasing duration of anoxia the relative abundance of the individuals of the family Cletodidae increased, and they survived the 1 month and 2 month anoxia, the latter with few specimens. They were the true "winners" of the experimentally induced anoxia. Dominance did not increase throughout all deployments because; not one, but several species from this family were tolerant to anoxia. The overall rate of survival was the same for males and females, but no juvenile stages of copepods survived in anoxia. During a recovery phase of 7 days after a short-term anoxia of 9 days, harpacticoid copepod density did not increase significantly, and there was only a slight increase in species diversity. We concluded that there was no substantial colonisation from the surrounding sediment. The survivors, however, showed a high potential for recovery according to the number of gravid females, whose number increased significantly once the oxygen was available again. These finding imply that a substantial amount of energy is allocated to reproduction in the recovery phase.

Grego, M.; Riedel, B.; Stachowitsch, M.; De Troch, M.

2013-07-01

106

TWO SHORT-TERM TOXICITY TESTS FOR THE CALANOID COPEPOD 'EURYTEMORA HERDMANI' USING A COMPLEX EFFLUENT  

EPA Science Inventory

Test designs and methodologies for two short-term static renewal tests, a 96-hr lethality test and a 5-day reproductive test, are described and statistically evaluated. The tests were developed specifically for use in the assessment of the toxicity of mixed effluents to copepods....

107

The parasitic copepod Lernaeocera branchialis negatively affects cardiorespiratory function in Gadus morhua.  

PubMed

The parasitic copepod Lernaeocera branchialis had a negative effect on cardiorespiratory function in Atlantic cod Gadus morhua such that it caused pronounced cardiac dysfunction with irregular rhythm and reduced stroke amplitude compared with uninfected fish. In addition, parasite infection depressed the postprandial cardiac output and oxygen consumption. PMID:24661216

Behrens, J W; Seth, H; Axelsson, M; Buchmann, K

2014-05-01

108

Changes in the distribution of copepods in the Gironde estuary: A warming and marinisation consequence?  

NASA Astrophysics Data System (ADS)

The Gironde is the largest estuary of South-West Europe and is one of the best monitored estuarine systems in the world. This macrotidal estuary is characterized by a low biodiversity in both oligo- and mesohaline zones. Its zooplankton community is constituted by only five major species, three calanoid copepods (including one invasive species) and two mysids. Retrospective analyses have already documented a warming associated to a phenomenon of marinisation. Here, we investigate the influence of both marinisation and warming on the spatial distribution and the abundance of copepods (i.e. Eurytemora affinis, Acartia bifilosa and neritic species) in the Gironde estuary. We modelled the environmental envelope of the copepods as a function of salinity and temperature to demonstrate that the alteration of their longitudinal distribution in the estuary between 1975 and 2003 was the result of both changing temperature and salinity. Although the upstream movement of neritic species was mostly related to salinity, we show that the augmentation of both temperature and salinity was at the origin of the upstream progression of both A. bifilosa and E. affinis. These results suggest that the distribution of copepods can be affected by both anthropogenic forcing and climatic change, which modulate the physic-chemistry of the Gironde estuary.

Chaalali, Aurélie; Chevillot, Xavier; Beaugrand, Grégory; David, Valérie; Luczak, Christophe; Boët, Philippe; Sottolichio, Aldo; Sautour, Benoît

2013-12-01

109

Seasonal occurrence of the tapeworm Proteocephalus longicollis and its transmission from copepod intermediate host to fish  

Microsoft Academic Search

Seasonal occurrence in terms of prevalence, intensity of infection, abundance and density of the tapeworm Proteocephalus longicollis (Zeder, 1800) and its transmission between its intermediate host ( Cyclops abyssorum prealpinus) and definitive host (common whitefish, Coregonus lavaretus) in Lake Annecy, an oligotrophic lake in the western part of the Alps, France, were studied in the period of 1998–2000. A copepod

V. Hanzelova ´; D. Gerdeaux

2003-01-01

110

Copepods in Turbid Shallow Soda Lakes Accumulate Unexpected High Levels of Carotenoids  

PubMed Central

Carotenoids are protective pigments present in many aquatic organisms that reduce the photooxidative stress induced by short-wavelenght solar radiation, yet increase their susceptibility to predators. Arctodiaptomus spinosus, a calanoid copepod typically found in many fishless shallow soda lakes, shows large between-lake differences in pigmentation. Here, we attribute these differences to the environmental state of these ecosystems, namely, ‘dark water’ lakes with submersed vegetation and turbid ‘white’ lakes lacking macrophytes. Copepod carotenoid concentration in the turbid ‘white’ lakes was significantly (about 20-fold) higher than in the ‘dark water’ ones, although the latter systems were characterized by higher transparency. In addition, males had on a dry weight basis around three times higher carotenoid concentrations than females. Mycosporine-like amino acids (direct UV screening substances) were found in all cases, but in low concentration. The environmental conditions in these ecosystems were largely shaped by the presence/absence of submersed macrophytes Thus, in the turbid lakes, the strong wind-driven mixis allows for copepods to be brought to the surface and being exposed to solar radiation, whereas in ‘dark water’ ones, macrophytes reduce water turbulence and additionally provide shelter. Our results explain the counter-intuitive notion of strong red pigmentation in copepods from a turbid ecosystem and suggest that factors other than high UV transparency favor carotenoid accumulation in zooplankton. PMID:22916208

Schneider, Tobias; Herzig, Alois; Koinig, Karin A.; Sommaruga, Ruben

2012-01-01

111

Egg production rates of the neritic marine copepod Acartia tumida Willey in the Aleutian Archipelago  

Microsoft Academic Search

Acartia tumida, a neritic copepod of the northern North Pacific Ocean and Bering Sea, is an unusually large member of its genus, adult females measuring 2.0–2.4 mm in total length. In the summers of 1986 and 1987 we investigated egg production of A. tumida in nearshore habitats of several islands in the Aleutian Island chain. A. tumida was found within

R. Patrick Hassett; David O. Duggins; Charles A. Simenstad

1993-01-01

112

DEMOGRAPHIC EVALUATION OF THE INFLUENCE OF TEMPERATURE AND SALINITY ON THE COPEPOD 'EURYTEMORA HERDMANI'  

EPA Science Inventory

Demographic responses of the estuarine copepod Eurytemora herdmani to several combinations of temperature and salinity were evaluated in the laboratory. Observed values of the intrinsic rate of population increase, r, ranged from -0.069/d to 0.088/d. Over the experimental range o...

113

Flux of particulate matter through copepods in the Northeast water polynya  

Microsoft Academic Search

Particulate organic carbon (POC) and nitrogen (PON) production by large calanoid copepods was investigated on the northeast Greenland shelf during August 1992 and May to August 1993. Both Calanus hyperboreus and C. glacialis females, when suspended in seawater collected from the chlorophyll maximum, produced about 40 pellets per day, which contained a carbon and nitrogen content equivalent to 8% and

Kendra L. Daly

1997-01-01

114

Projected marine climate change: effects on copepod oxidative status and reproduction.  

PubMed

Zooplankton are an important link between primary producers and fish. Therefore, it is crucial to address their responses when predicting effects of climate change on pelagic ecosystems. For realistic community-level predictions, several biotic and abiotic climate-related variables should be examined in combination. We studied the combined effects of ocean acidification and global warming predicted for year 2100 with toxic cyanobacteria on the calanoid copepod, Acartia bifilosa. Acidification together with higher temperature reduced copepod antioxidant capacity. Higher temperature also decreased egg viability, nauplii development, and oxidative status. Exposure to cyanobacteria and its toxin had a negative effect on egg production but, a positive effect on oxidative status and egg viability, giving no net effects on viable egg production. Additionally, nauplii development was enhanced by the presence of cyanobacteria, which partially alleviated the otherwise negative effects of increased temperature and decreased pH on the copepod recruitment. The interactive effects of temperature, acidification, and cyanobacteria on copepods highlight the importance of testing combined effects of climate-related factors when predicting biological responses. PMID:24340194

Vehmaa, Anu; Hogfors, Hedvig; Gorokhova, Elena; Brutemark, Andreas; Holmborn, Towe; Engström-Öst, Jonna

2013-11-01

115

Copepods of the family Ergasilidae (Poecilostomatoida) parasitic on fishes from Khor al-Zubair Lagoon, Iraq  

Microsoft Academic Search

Four species of ergasilid copepods were collected from gill filaments of three species of fishes from Khor al-Zubair Lagoon, Iraq. The mugilid Liza subviridis hosted the new species Ergasilus iraquensis and Ergasilus pararostralis. Ergasilus synanceienis sp. n. was found on the synanceiid Leptosynanceia melanostigma(Day). The fourth species, Dermoergasilus varicoleus Ho, Jayarajan & Radhakrishnan, 1992 was found parasitizing the mugilid Liza

Maria Auxiliadora Pinto da Motta Amado; Carlos Eduardo Falavigna da Rocha; Wojciech Piasecki; Salem A. M. Al-Daraji; Furhan T. Mhaisen

2001-01-01

116

Diel distribution of copepods across a channel of an overwash mangrove island  

Microsoft Academic Search

The distribution of copepod species and their nauplii was studied in a narrow, blind channel on an overwash mangrove island offshore of Belize. Copepodids were sampled with a pump at five stations across the channel during a diel cycle. Diel changes of copepodid stages II – VI were marked by horizontal dispersal of Dioithona oculata, the dominant species, from swarms

Frank D. Ferrari; John A. Fornshell; Lana Ong; Julie W. Ambler

2003-01-01

117

Propulsion efficiency and cost of transport for copepods: a hydromechanical model of crustacean swimming  

Microsoft Academic Search

In the absence of direct measurement, costs of locomotion to small swimming Crustacea (Pleuromamma xiphias (Calanoida) was analyzed by extrapolating model parameters from data available in the literature. The model predictions agree well with empirical observations reported for larger crustaceans, in that swimming for copepods is relatively costly. The ratio of active to standard metabolism for P. xiphias was >3.

M. J. Morris; G. Gust; J. J. Torres

1985-01-01

118

PLANKTONIC DEEP-WATER COPEPODS OF THE FAMILY MORMONILLIDAE GIESBRECHT, 1893 FROM THE EAST PACIFIC RISE  

E-print Network

PLANKTONIC DEEP-WATER COPEPODS OF THE FAMILY MORMONILLIDAE GIESBRECHT, 1893 FROM THE EAST PACIFIC., common in plankton of the northeastern Atlantic, are studied anew. Females of N. polaris (G.O. Sars, 1900) comb. nov., from plankton near the North Pole (Arctic Ocean, depths 300-1000 m) are re

Ivanenko, Viatcheslav N.

119

Marine Landscapes and Faunal Recruitment: A Field Test with Seagrasses and Copepods  

Microsoft Academic Search

The influence of plant landscapes on recruitment of meiofaunal copepods was investigated in a New Zealand seagrass bed. Artificial plant mimics were placed into sediments at levels equivalent to natural blade densities (100 units per 0.5 x 0.25 m plot) in a variety of experimental treatments and retrieved 3 or 5 d later. To assess the effect of plant arrangement

Susan S. Bell; G. R. F. Hicks

1991-01-01

120

COMPARATIVE QUALITY OF ROTIFERS AND COPEPODS AS FOODS FOR LARVAL FISHES  

Microsoft Academic Search

The rotifer Brachionus plicatilis and the copepod Tigriopus californicus are easily cultured and com- monly used as foods for larval fishes. Sizes of rotifers, nauplii, and copepodites, ranging in width from 74 to 221 pm, were related to their weight, volume, and caloric content. Between the smallest and largest size classes-a width increase of two times-rotifer dry weight increased from

GAIL H. THEILACKER; AMY S. KIMBALL

121

Hatching and viability of copepod eggs at two stages of embryological development: anoxic\\/hypoxic effect  

Microsoft Academic Search

The effects of low oxygen concentrations on the hatching and viability of copepod eggs at two stages of embryological development were investigated. Fully developed eggs from Acartia tonsa (Dana) and Labidocera aestiva (Wheeler) collected between July and September 1991 at Turkey Point, Florida, USA, hatched at lower oxygen concentrations than newly spawned eggs given the same incubation periods. Since many

R. V. Lutz; N. H. Marcus; J. P. Chanton

1994-01-01

122

Hydrostatic Pressure and Temperature Effects on the Membranes of a Seasonally Migrating Marine Copepod  

PubMed Central

Marine planktonic copepods of the order Calanoida are central to the ecology and productivity of high latitude ecosystems, representing the interface between primary producers and fish. These animals typically undertake a seasonal vertical migration into the deep sea, where they remain dormant for periods of between three and nine months. Descending copepods are subject to low temperatures and increased hydrostatic pressures. Nothing is known about how these organisms adapt their membranes to these environmental stressors. We collected copepods (Calanoides acutus) from the Southern Ocean at depth horizons ranging from surface waters down to 1000 m. Temperature and/or pressure both had significant, additive effects on the overall composition of the membrane phospholipid fatty acids (PLFAs) in C. acutus. The most prominent constituent of the PLFAs, the polyunsaturated fatty acid docosahexanoic acid [DHA – 22:6(n-3)], was affected by a significant interaction between temperature and pressure. This moiety increased with pressure, with the rate of increase being greater at colder temperatures. We suggest that DHA is key to the physiological adaptations of vertically migrating zooplankton, most likely because the biophysical properties of this compound are suited to maintaining membrane order in the cold, high pressure conditions that persist in the deep sea. As copepods cannot synthesise DHA and do not feed during dormancy, sufficient DHA must be accumulated through ingestion before migration is initiated. Climate-driven changes in the timing and abundance of the flagellated microplankton that supply DHA to copepods have major implications for the capacity of these animals to undertake their seasonal life cycle successfully. PMID:25338196

Pond, David W.; Tarling, Geraint A.; Mayor, Daniel J.

2014-01-01

123

Blastodinium spp. infect copepods in the ultra-oligotrophic marine waters of the Mediterranean Sea  

NASA Astrophysics Data System (ADS)

Blastodinium are chloroplast-containing dinoflagellates which infect a wide range of copepods. They develop inside the gut of their host, where they produce successive generations of sporocytes that are eventually expelled through the anus of the copepod. Here, we report on copepod infections in the oligotrophic to ultra-oligotrophic waters of the Mediterranean Sea sampled during the BOUM cruise. Based on a DNA-stain screening of gut contents, 16% of copepods were possibly infected in samples from the Eastern Mediterranean, with up to 51% of Corycaeidae, 33% of Calanoida, but less than 2% of Oithonidae and Oncaeidae. Parasites were classified into distinct morphotypes, with some tentatively assigned to species B. mangini, B. contortum, and B. cf. spinulosum. Based upon the SSU rDNA gene sequence analyses of 15 individuals, the genus Blastodinium was found to be polyphyletic, containing at least three independent clusters. The first cluster grouped all sequences retrieved from parasites of Corycaeidae and Oncaeidae during this study, and included sequences of Blastodinium mangini (the "mangini" cluster). Sequences from cells infecting Calanoida belonged to two different clusters, one including B. contortum (the "contortum" cluster), and the other uniting all B. spinulosum-like morphotypes (the "spinulosum" cluster). Cluster-specific oligonucleotidic probes were designed and tested by FISH in order to assess the distribution of dinospores, the Blastodinium dispersal and infecting stage. Probe-positive cells were all small thecate dinoflagellates, with lengths ranging from 7 to 18 ?m. Maximal abundances of Blastodinium dinospores were detected at the Deep Chlorophyll Maximum (DCM) or slightly below. This was in contrast to distributions of autotrophic pico- and nanoplankton, microplanktonic dinoflagellates, and nauplii which showed maximal concentrations above the DCM. The distinct distributions of dinospores and nauplii argues against infection during the naupliar stage. Blastodinium, described as autotrophic in the literature, may escape the severe nutrient limitation of ultra-oligotrophic ecosystems by living inside copepods.

Alves-de-Souza, C.; Cornet, C.; Nowaczyk, A.; Gasparini, S.; Skovgaard, A.; Guillou, L.

2011-03-01

124

Explaining regional variability in copepod recruitment: Implications for a changing climate  

NASA Astrophysics Data System (ADS)

Characterizing environmental effects on copepod production and their ecological roles is complicated by multiple physical (e.g. temperature) and biological (e.g. food, predation) factors controlling multiple aspects of copepod physiology and demography. For example, data for two regions in eastern Canada (St. John’s, Newfoundland and Halifax, Nova Scotia) indicate that subtle differences in environmental conditions lead to significant differences in seasonal copepod ( Calanus finmarchicus) recruitment timing and magnitude. Here, we quantify how environmental variability influences C. finmarchicus physiology and demography leading to observed regional and seasonal variations in abundance off St. John’s and Halifax. We apply a stochastic individual-based model (IBM) for copepod population dynamics to simulate the seasonal variation in C. finmarchicus abundance of egg through copepodite 1 (C1) stages at the two sites using year-specific local forcing from multi-year data. The model includes individual variability in development, egg production and mortality rates with resulting seasonal C1 abundance averaged among years and compared to analogous observations. We find temperature has a dominant effect on both development and egg production rates while egg recruitment is affected by temperature and female abundance at both sites. We show that mortality rate characterization has a strong influence on modeled abundances, and site-specific environmentally dependent mortality rates are necessary to produce results consistent with observations (temperature vs. food vs. cannibalism via females). Results indicate that prediction of climate change effects on copepod abundance and their ecological roles requires consideration of biological (e.g. chlorophyll a, female abundance) as well as physical (e.g. temperature) factors. In particular, estimates of abundances during the onset of C1 recruitment (i.e. their arrival on the larval fish prey field) are improved by 67-94% when the influence of biological factors on mortality rates are considered.

Neuheimer, A. B.; Gentleman, W. C.; Pepin, P.; Head, E. J. H.

2010-10-01

125

Tools for crushing diatoms - opal teeth in copepods feature a rubber-like bearing composed of resilin  

PubMed Central

Diatoms are generally known for superior mechanical properties of their mineralised shells. Nevertheless, many copepod crustaceans are able to crush such shells using their mandibles. This ability very likely requires feeding tools with specific material compositions and properties. For mandibles of several copepod species silica-containing parts called opal teeth have been described. The present study reveals the existence of complex composite structures, which contain, in addition to silica, the soft and elastic protein resilin and form opal teeth with a rubber-like bearing in the mandibles of the copepod Centropages hamatus. These composite structures likely increase the efficiency of the opal teeth while simultaneously reducing the risk of mechanical damage. They are supposed to have coevolved with the diatom shells in the evolutionary arms race, and their development might have been the basis for the dominance of the copepods within today's marine zooplankton. PMID:22745896

Michels, Jan; Vogt, Jurgen; Gorb, Stanislav N.

2012-01-01

126

Modelling physico-chemical factors affecting occurrences of a non-indigenous planktonic copepod in northeast Pacific estuaries  

Microsoft Academic Search

Estuarine ecosystems along the Pacific coast of North America are vulnerable to invasions by non-indigenous planktonic copepods,\\u000a with documented invasions by at least nine species introduced via ship’s ballast. One of these, the calanoid copepod Pseudodiaptomus inopinus, now occurs in a relatively wide geographical area in coastal estuaries of Washington and Oregon States. Although it appears\\u000a to be well established

Jeffery R. Cordell; Lucinda M. Tear; Stephen M. Bollens

2010-01-01

127

Assessment of the Roles of Copepod Apocyclops royi and Bivalve Mollusk Meretrix lusoria in White Spot Syndrome Virus Transmission  

Microsoft Academic Search

Here, we investigate the roles of copepods and bivalve mollusks in the transmission of white spot syndrome virus (WSSV), which\\u000a is the causative pathogen of an acute, contagious disease that causes severe mortalities in cultured shrimp. Copepods are\\u000a common components in seawater ponds and are often eaten as live food by shrimp post-larvae. WSSV has been detected in these\\u000a animals,

Yun-Shiang Chang; Tsan-Chi Chen; Wang-Jing Liu; Jiang-Shiou Hwang; Guang-Hsiung Kou; Chu-Fang Lo

128

Assessment of storage lipid accumulation patterns in eucalanoid copepods from the eastern tropical Pacific Ocean  

NASA Astrophysics Data System (ADS)

Members of the copepod family Eucalanidae are widely distributed throughout the world's oceans and have been noted for their accumulation of storage lipids in high- and low-latitude environments. However, little is known about the lipid composition of eucalanoid copepods in low-latitude environments. The purpose of this study was to examine fatty acid and alcohol profiles in the storage lipids (wax esters and triacylglycerols) of Eucalanus inermis, Rhincalanus rostrifrons, R. nasutus, Pareucalanus attenuatus, and Subeucalanus subtenuis, collected primarily in the eastern tropical north Pacific near the Tehuantepec Bowl and Costa Rica Dome regions, noted for its oxygen minimum zone, during fall 2007 and winter 2008/2009. Adult copepods and particulate material were collected in the upper 50 m and from 200 to 300 m in the upper oxycline. Lipid profiles of particulate matter were generated to help ascertain information on ecological strategies of these species and on differential accumulation of dietary and modified fatty acids in the wax ester and triacylglycerol storage lipid components of these copepods in relation to their vertical distributions around the oxygen minimum zone. Additional data on phospholipid fatty acid and sterol/fatty alcohol fractions were also generated to obtain a comprehensive lipid data set for each sample. Rhincalanus spp. accumulated relatively large amounts of storage lipids (31-80% of dry mass (DM)), while E. inermis had moderate amounts (2-9% DM), and P. attenuatus and S. subtenuis had low quantities of storage lipid (0-1% DM). E. inermis and S. subtenuis primarily accumulated triacylglycerols (>90% of storage lipids), while P. attenuatus and Rhincalanus spp. primarily accumulated wax esters (>84% of storage lipids). Based on previously generated molecular phylogenies of the Eucalanidae family, these results appear to support genetic predisposition as a major factor explaining why a given species accumulates primarily triacylglycerols or wax esters, and also potentially dictating major fatty acid and alcohol accumulation patterns within the more highly modified wax ester fraction. Comparisons of fatty acid profiles between triacylglycerol and wax ester components in copepods with that in available prey suggested that copepod triacylglycerols were more reflective of dietary fatty acids, while wax esters contained a higher proportion of modified or de novo synthesized forms. Sterols and phospholipid fatty acids were similar between species, confirming high levels of regulation within these components. Similarities between triacylglycerol fatty acid profiles of E. inermis collected in surface waters and at >200 m depth indicate little to no feeding during their ontogenetic migration to deeper, low-oxygen waters.

Cass, Christine J.; Daly, Kendra L.; Wakeham, Stuart G.

2014-11-01

129

Flux of particulate matter through copepods in the Northeast water polynya  

NASA Astrophysics Data System (ADS)

Particulate organic carbon (POC) and nitrogen (PON) production by large calanoid copepods was investigated on the northeast Greenland shelf during August 1992 and May to August 1993. Both Calanus hyperboreus and C. glacialis females, when suspended in seawater collected from the chlorophyll maximum, produced about 40 pellets per day, which contained a carbon and nitrogen content equivalent to 8% and 6% of body carbon, respectively, and 2% of body nitrogen. In experiments, the carbon:nitrogen (C:N) ratio by weight of suspended particulates, C. hyperboreus, and fecal pellets was 6.7, 7.7 and 28.5, respectively. The unusually high C:N ratio for pellets, in part, may be attributed to elevated ratios of > 20?m size fractions of particulate organic matter, the size fraction more common in the diet of these large copepods and the fraction dominated by diatoms according to microscopic and pigment data. The implied elevated C:N ratios of large phytoplankton cells were probably due to nitrogen deficiency, as shown by other studies in this region. In addition, female C. hyperboreus appeared to be more efficient in assimilating nitrogen than carbon, which also would have contributed to high C:N ratios in egested pellets. Unfractionated POC concentrations explained 54% of the variability in carbon egestion and 70% of the variability in nitrogen egestion in copepods, whereas copepod body content accounted for little of the variation on the short time scales of the experiments. Carbon egestion by C. hyperboreus was positively correlated with POC concentrations at the depth of the chlorophyll maximum, while nitrogen egestion was negatively correlated with PON concentrations in the euphotic zone. Estimates of potential community egestion rates for the upper water column indicate that copepods represent a major pathway of organic carbon transformation in this Arctic shelf system. On average, copepods may have ingested 45% of the primary production and egested fecal matter equivalent to 20% of the carbon and 12% of the nitrogen particulate flux sedimenting from the surface layer. However, several lines of evidence suggest that pellets were remineralized in the water column and, hence, may have contributed little organic carbon and nitrogen to the benthos.

Daly, Kendra L.

1997-01-01

130

Bioaccumulation of photoprotective compounds in copepods: environmental triggers and sources of intra-specific variability  

NASA Astrophysics Data System (ADS)

Ultraviolet radiation (UVR) and temperature are two globally important abiotic factors affecting freshwater ecosystems. Planktonic organisms have developed a battery of counteracting mechanisms to minimize the risk of being damaged by UVR, which respond to three basic principles: avoid, protect, repair. Copepods are among the most successful zooplankton groups. They are highly adaptable animals, capable of displaying flexible behaviors, physiologies, and life strategies. In particular, they are well equipped to cope with harmful UVR. Their arsenal includes vertical migration, accumulation of photoprotective compounds, and photorepair. The preference for a particular strategy is affected by a plethora of environmental (extrinsic) parameters, such as the existence of a depth refuge, the risk of visual predation, and temperature. Temperature modifies the environment (e.g. the lake thermal structure), and animal metabolism (e.g., swimming speed, bioaccumulation of photoprotective compounds). In addition, the relative weight of UVR-coping strategies is also influenced by the organism (intrinsic) characteristics (e.g., inter- and intra-specific variability). The UV absorbing compounds, mycosporine-like amino acids (MAAs), are widely distributed among freshwater copepods. Animals are unable to synthesize MAAs, and therefore depend on external sources for accumulating these compounds. Although copepods may acquire MAAs from their food, for the few centropagic species investigated so far, the main source of MAAs are microbial (most likely prokaryotic) organisms living in close association with the copepods. Boeckella gracilipes is a common centropagic copepod in Patagonian lakes. We suspected that its occurrence in different types of lakes, hydrologically unconnected, but within close geographical proximity, could have resulted in different microbial-copepod associations (i.e., different MAAs sources) that could translate into intra-specific differences in the accumulation of MAAs when experimentally exposed to different combinations of radiation exposure and temperature. We exposed B. gracilipes individuals from two lakes (Verde: high elevation, fishless; Morenito: piedmont, with fish) to two radiation conditions (PAR+UVA vs. darkness) crossed with five temperatures (5, 8, 12, 16 and 20 C) for periods of 10 days. DNA fingerprinting (DGGE) revealed the existence of differences in microbial composition between the two copepod populations. The two populations differed in initial total MAAs concentration and composition. Exposure to PAR+UVR stimulated the accumulation of MAAs in individuals from lake Morenito and to a lesser extent in those from lake Verde. There were significant differences in the rates of MAAs accumulation between the two populations. More specifically, individuals from lake Morenito had a higher propensity to lose and gain MAAs that those from Lake Verde, which maintain a more stable MAA concentration regardless of the experimental conditions. Temperature affected the concentration of MAAs in individuals maintained in darkness. As expected, the individuals tended to lose MAAs at higher temperatures. Unexpectedly however, the lower temperatures stimulated the accumulation of MAAs, even when the copepods were in the dark. Thus, low temperature by itself may induce MAA accumulation.

Zagarese, H. E.; García, P.; Diéguez, M. D.; Ferraro, M. A.

2012-12-01

131

Lipid composition of the copepod Calanus hyperboreas from the Arctic Ocean. Changes with depth and season  

Microsoft Academic Search

A build-up of reserve lipid, predominantly wax esters, occurred during the summer in the copepod Calanus hyperboreas, collected off an Arctic ice-island. This lipid storage was correlated with a phytoplankton bloom and was followed by a progressive decrease of lipid from 2.1 mg per individual in September to 0.4 mg in June. There was a rapid decrease in lipid utilization

R. F. Lee

1974-01-01

132

Cladocerans versus copepods: the cause of contrasting top–down controls on freshwater and marine phytoplankton  

Microsoft Academic Search

Top–down control of phytoplankton by crustacean mesozooplankton is a cornerstone of freshwater ecology. Apparently, trophic\\u000a cascades are more frequently reported from freshwater than from marine plankton. We argue that this difference is real and\\u000a mainly caused by biological differences at the zooplankton–phytoplankton link: cladocerans (particularly Daphnia) in the lakes and copepods in the sea. We derive these conclusions from recent

Ulrich Sommer; Frank Sommer

2006-01-01

133

Annual biomass and production of the oceanic copepod community off Discovery Bay, Jamaica  

Microsoft Academic Search

Monthly samples were collected in oceanic waters off Discovery Bay, Jamaica, in 60- and 200-m vertical hauls, using 200- and 64-µm mesh plankton nets, from June 1989 to July 1991. Length-weight regressions were derived for twelve genera of copepods (R2=0.79 to 0.97). For eight occasions spanning the study period, biomass estimates generated from these length-weight regressions differed by only 3%

M. K. Webber; J. C. Roff

1995-01-01

134

Recombination in interpopulation hybrids of the copepod Tigriopus californicus: release of beneficial variation despite hybrid breakdown.  

PubMed

Crosses between divergent populations of the copepod Tigriopus californicus typically result in fitness reductions for both F2 and backcross hybrids. Because females in this species lack chiasmatic meiosis, both recombinant and nonrecombinant backcross hybrids can be created. Recombinant hybrids were found to have significantly faster development time for both males and females in 2 pairs of crosses, indicating the creation of favorable gene combinations by disrupting parental linkage groups. PMID:18308715

Edmands, Suzanne

2008-01-01

135

Mediterranean marine copepods: basin-scale trends of the calanoid Centropages typicus  

Microsoft Academic Search

The Mediterranean Sea is located in a crossroad of mid-latitude and subtropical climatic modes that enhance contrasting environmental\\u000a conditions over both latitudinal and longitudinal ranges. Here, we show that the large-scale environmental forcing is reflected\\u000a in the basin scale trends of the adult population of the calanoid copepod Centropages typicus. The species is distributed over the whole Mediterranean basin, and

J. C. Molinero; V. Vukani?; D. Lu?i?; F. Ibanez; P. Nival; P. Licandro; A. Calbet; E. D. Christou; N. Daly-Yahia; M. L. Fernandez de Puelles; M. G. Mazzocchi; I. Siokou-Frangou

2009-01-01

136

Seasonal occurrence of the tapeworm Proteocephalus longicollis and its transmission from copepod intermediate host to fish.  

PubMed

Seasonal occurrence in terms of prevalence, intensity of infection, abundance and density of the tapeworm Proteocephalus longicollis (Zeder, 1800) and its transmission between its intermediate host (Cyclops abyssorum prealpinus) and definitive host (common whitefish, Coregonus lavaretus) in Lake Annecy, an oligotrophic lake in the western part of the Alps, France, were studied in the period of 1998-2000. A copepod Cyclops abyssorum prealpinus (Kiefer, 1939), the dominant species among planktonic crustaceans in the lake, served as the only intermediate host for this parasite. Infection with plerocercoids was higher in adult copepods (predominantly females) than in copepodite stages IV and V. The prevalence rate of 25% found in C. abyssorum prealpinus females in June 1998 represents a unique infection rate of intermediate hosts with fish tapeworms in natural conditions. The final host, the common whitefish Coregonus lavaretus (L.), was heavily infected with P. longicollis throughout the year (prevalence 90%; mean abundance 40.3; maximum intensity of infection more than 500 tapeworms per fish); immature tapeworms predominated in all samples (P<0.01). Transmission of tapeworm larvae from copepods to the common whitefish took place most intensively in summer and autumn, and depended on seasonal changes in the density of the C. abyssorum prealpinus population, infection of this copepod with plerocercoids and their density in the lake. In addition, transmission efficiency also seems to be determined by the longevity of tapeworm larvae in the intermediate host, timing of predation of the fish host and rapid development of the parasite within this host during the summer period. Overall transmission potential of P. longicollis was low, with only about 9% of juvenile specimens reaching maturity in common whitefish. PMID:12910414

Hanzelová, V; Gerdeaux, D

2003-09-01

137

Daphnia versus copepod impact on summer phytoplankton: functional compensation at both trophic levels  

Microsoft Academic Search

Here we report on a mesocom study performed to compare the top-down impact of microphagous and macrophagous zooplankton on phytoplankton. We exposed a species-rich, summer phytoplankton assemblage from the mesotrophic Lake Schöhsee (Germany) to logarithmically scaled abundance gradients of the microphagous cladoceran Daphnia hyalina2galeata and of a macrophagous copepod assemblage. Total phytoplankton biomass, chlorophyll a and primary production showed only

Ulrich Sommer; Frank Sommer; Barbara Santer; Eckart Zöllner; Klaus Jürgens; Colleen Jamieson; Maarten Boersma; Klaus Gocke

2003-01-01

138

Molecular Evidence of the Toxic Effects of Diatom Diets on Gene Expression Patterns in Copepods  

PubMed Central

Background Diatoms are dominant photosynthetic organisms in the world's oceans and are considered essential in the transfer of energy through marine food chains. However, these unicellular plants at times produce secondary metabolites such as polyunsaturated aldehydes and other products deriving from the oxidation of fatty acids that are collectively termed oxylipins. These cytotoxic compounds are responsible for growth inhibition and teratogenic activity, potentially sabotaging future generations of grazers by inducing poor recruitment in marine organisms such as crustacean copepods. Principal Findings Here we show that two days of feeding on a strong oxylipin-producing diatom (Skeletonema marinoi) is sufficient to inhibit a series of genes involved in aldehyde detoxification, apoptosis, cytoskeleton structure and stress response in the copepod Calanus helgolandicus. Of the 18 transcripts analyzed by RT-qPCR at least 50% were strongly down-regulated (aldehyde dehydrogenase 9, 8 and 6, cellular apoptosis susceptibility and inhibitor of apoptosis IAP proteins, heat shock protein 40, alpha- and beta-tubulins) compared to animals fed on a weak oxylipin-producing diet (Chaetoceros socialis) which showed no changes in gene expression profiles. Conclusions Our results provide molecular evidence of the toxic effects of strong oxylipin-producing diatoms on grazers, showing that primary defense systems that should be activated to protect copepods against toxic algae can be inhibited. On the other hand other classical detoxification genes (glutathione S-transferase, superoxide dismutase, catalase, cytochrome P450) were not affected possibly due to short exposure times. Given the importance of diatom blooms in nutrient-rich aquatic environments these results offer a plausible explanation for the inefficient use of a potentially valuable food resource, the spring diatom bloom, by some copepod species. PMID:22046381

Lauritano, Chiara; Borra, Marco; Carotenuto, Ylenia; Biffali, Elio; Miralto, Antonio; Procaccini, Gabriele; Ianora, Adrianna

2011-01-01

139

Spring dominant copepods and their distribution pattern in the yellow sea  

Microsoft Academic Search

We investigated the relationship between mesoscale spatial distribution of environmental parameters (temperature, salinity,\\u000a and sigma-t), chlorophyll-a concentration and mesozooplankton in the Yellow Sea during May 1996, 1997, and 1998, with special reference to Yellow Sea\\u000a Bottom Cold Water (YSBCW). Adult calanoid copepods,Calanus sinicus, Paracalanus parvus s.l.,Acartia omorii, andCentropages abdominalis were isolated by BVSTEP analysis based on the consistent explainable percentage

Jung-Hoon Kang; Woong-Seo Kim

2008-01-01

140

Spatial and temporal distributions of copepods to leeward and windward of Oahu, Hawaiian Archipelago  

Microsoft Academic Search

The spatial and temporal distributions of two island-associated copepod species, Undinula vulgaris Dana and Labidocera madurae Scott, were compared to the distributions of two open ocean species, Cosmocalanus darwinii Lubbock and Scolecithrix danae Lubbock, along 28-km windward and leeward transects off the island of Oahu, Hawaii. Samples were taken in September and December\\u000a 1985 and April and June 1986. A

R. P. Hassett; G. W. Boehlert

1999-01-01

141

Response of copepod grazing and reproduction to different taxa of spring bloom phytoplankton in the Southern Yellow Sea  

NASA Astrophysics Data System (ADS)

The responses of copepod grazing and reproduction to the spring phytoplankton bloom were studied in the temperate shelf water of the Southern Yellow Sea in March-April, 2009. Two different algal blooms were found during the cruises. A diatom-dominated bloom at Station Z11, and a dinoflagellate-dominated bloom at Station Z4. The gut pigment contents indicated that different sized copepods exhibited different responses to different-species phytoplankton blooms. Large copepods (LC: body size larger than 1000 ?m) and medium copepods (MC: body size ranging from 500 to 1000 ?m), grazed actively on diatom blooms, but inactively on dinoflagellate blooms, although the chlorophyll-a concentrations of dinoflagellate blooms were twice as high as than those of the diatom blooms. For small copepods (SC: body size smaller than 500 ?m), however, there was no significant difference in gut pigment contents between the two different algal blooms. Among the three size groups, LCs were the major grazers on the diatom bloom, while SCs were major grazers on the dinoflagellate bloom. Grazing impacts of copepod assemblages on phytoplankton blooms were low, only being equivalent to 1% day-1, or less, of the chlorophyll-a standing stock. The egg production rates of a large copepod, Calanus sinicus, were on average, 11.3 egg ind.-1 day-1, which was among the higher levels recorded in the study area, especially at the two stations where phytoplankton was blooming (21.8 and 14.9 egg ind.-1 day-1 at Stations Z11 and Z4, respectively). However, C. sinicus could only obtain sufficient food to support this high reproduction from the diatom bloom, but could not if relying only on the apparently unpalatable dinoflagellate bloom. Our analysis of copepod grazing and reproduction suggests that, although the spring blooms do enhance the reproduction of copepods, the taxa changed during spring blooms from large diatoms to small dinoflagellates would change the pathway of primary production. This would restructure secondary-producers (e.g. copepods) community structure, and have important ramifications through various marine trophic levels in the Southern Yellow Sea.

Li, Chaolun; Yang, Guang; Ning, Juan; Sun, Jun; Yang, Bo; Sun, Song

2013-12-01

142

First report of ciliate (Protozoa) epibionts on deep-sea harpacticoid copepods  

NASA Astrophysics Data System (ADS)

We report the first observations of ciliate epibionts on deep-sea, benthic harpacticoid copepods. One ciliate epibiont species belonged to class Karyorelictea, one to subclass Suctoria, and one to subclass Peritrichia. Our samples came from the continental rise off central California (36.709°N, 123.523°W, 3607 m depth). We found that adult harpacticoids carried ciliate epibionts significantly more frequently than did subadult copepodids. The reason for the pattern is unknown, but it may involve differences between adults and subadult copepodids in size or in time spent swimming. We also found that the ciliate epibiont species occurred unusually frequently on the adults of two species of harpacticoid copepod; a third harpacticoid species just failed the significance test. When we ranked the 57 harpacticoid species in our samples in order of abundance, three species identified were, as a group, significantly more abundant than expected by chance if one assumes that the abundance of the group and the presence of ciliate epibionts on them were uncorrelated. High abundance may be among the reasons a harpacticoid species carries a ciliate epibiont species disproportionately frequently. For the combinations of harpacticoid species and ciliate epibiont species identified, we found one in which males and females differed significantly in the proportion that carried epibionts. Such a sex bias has also been reported for shallow-water, calanoid copepods.

Sedlacek, Linda; Thistle, David; Fernandez-Leborans, Gregorio; Carman, Kevin R.; Barry, James P.

2013-08-01

143

Transcriptome Sequencing and De Novo Analysis of the Copepod Calanus sinicus Using 454 GS FLX  

PubMed Central

Background Despite their species abundance and primary economic importance, genomic information about copepods is still limited. In particular, genomic resources are lacking for the copepod Calanus sinicus, which is a dominant species in the coastal waters of East Asia. In this study, we performed de novo transcriptome sequencing to produce a large number of expressed sequence tags for the copepod C. sinicus. Results Copepodid larvae and adults were used as the basic material for transcriptome sequencing. Using 454 pyrosequencing, a total of 1,470,799 reads were obtained, which were assembled into 56,809 high quality expressed sequence tags. Based on their sequence similarity to known proteins, about 14,000 different genes were identified, including members of all major conserved signaling pathways. Transcripts that were putatively involved with growth, lipid metabolism, molting, and diapause were also identified among these genes. Differentially expressed genes related to several processes were found in C. sinicus copepodid larvae and adults. We detected 284,154 single nucleotide polymorphisms (SNPs) that provide a resource for gene function studies. Conclusion Our data provide the most comprehensive transcriptome resource available for C. sinicus. This resource allowed us to identify genes associated with primary physiological processes and SNPs in coding regions, which facilitated the quantitative analysis of differential gene expression. These data should provide foundation for future genetic and genomic studies of this and related species. PMID:23671698

Ning, Juan; Wang, Minxiao; Li, Chaolun; Sun, Song

2013-01-01

144

Deleterious epistatic interactions between electron transport system protein-coding loci in the copepod Tigriopus californicus.  

PubMed

The nature of epistatic interactions between genes encoding interacting proteins in hybrid organisms can have important implications for the evolution of postzygotic reproductive isolation and speciation. At this point very little is known about the fitness differences caused by specific closely interacting but evolutionarily divergent proteins in hybrids between populations or species. The intertidal copepod Tigriopus californicus provides an excellent model in which to study such interactions because the species range includes numerous genetically divergent populations that are still capable of being crossed in the laboratory. Here, the effect on fitness due to the interactions of three complex III proteins of the electron transport system in F2 hybrid copepods resulting from crosses of a pair of divergent populations is examined. Significant deviations from Mendelian inheritance are observed for each of the three genes in F2 hybrid adults but not in nauplii (larvae). The two-way interactions between these genes also have a significant impact upon the viability of these hybrid copepods. Dominance appears to play an important role in mediating the interactions between these loci as deviations are caused by heterozygote/homozygote deleterious interactions. These results suggest that the fitness consequences of the interactions of these three complex III-associated genes could influence reproductive isolation in this system. PMID:16624922

Willett, Christopher S

2006-07-01

145

Habitat temperature is an important determinant of cholesterol contents in copepods  

PubMed Central

Summary Effects of habitat and acclimation temperature on cholesterol contents were examined in oceanic and inshore species of copepods. The cholesterol content of five species of thermally acclimated copepods was determined, and nine species (representing six families) were sampled to assess the role of habitat temperature. The species selected have maximum habitat temperatures (and temperature tolerances) that vary at least twofold. Levels of dietary cholesterol required to achieve maximum growth were also studied at different acclimation temperatures in a eurythermal copepod. Both eggs and copepodites of Calanus finmarchicus had higher cholesterol levels at the warm acclimation temperature (16°C) than at the cooler temperature (6°C). Neither Acartia tonsa, Acartia hudsonica, Temora longicornis nor Eurytemora affinis altered cholesterol contents with acclimation temperature. Maximum growth rates were achieved at fourfold higher concentrations of dietary cholesterol in warm-acclimated Eurytemora affinis than in cold-acclimated animals. The most consistent trend is the positive relationship between cholesterol content and habitat temperature. Species residing in warmer habitats (e.g. Centropages typicus, Eurytemora affinis) had approximately twice the cholesterol of species living in colder waters (e.g. Calanus glacialis, Euchaeta norvegica). A similar pattern was observed for comparisons of species within genera (Calanus, Acartia and Centropages), with the species abundant at lower latitudes having more cholesterol than the northern congener. These data indicate that habitat temperature is an important determinant of cholesterol content, and cholesterol endows membranes with the stability required for a range of body temperatures. PMID:19088212

Hassett, R. Patrick; Crockett, Elizabeth L.

2009-01-01

146

First record of Neoergasilus japonicus (Poecilostomatoida: Ergasilidae), a parasitic copepod new to the Laurentian Great Lakes  

USGS Publications Warehouse

The parasitic copepod Neoergasilus japonicus, native to eastern Asia, was first collected from 4 species of fish (fathead minnow, Pimephales promelas; largemouth bass, Micropterus salmoides; pumpkinseed sunfish, Lepomis gibbosus; and yellow perch, Perca flavescens) in July 1994 in Saginaw Bay, Lake Huron, Michigan. Further sampling in the bay in 2001 revealed infections on 7 additional species (bluegill, Lepomis macrochirus; carp, Cyprinus carpio; channel catfish, Ictalurus punctatus; goldfish, Carassius auratus; green sunfish, Lepomis cyanellus; rock bass, Ambloplites rupestris; and smallmouth bass, Micropterus dolomieu). An additional 21 species examined in 2001 were devoid of the parasite. A limited collection of fish from Lake Superior (n = 8) and Lake Michigan (n = 46) in 1994 showed no infection. Neoergasilus japonicus is most frequently found attached to the dorsal fin and, in decreasing frequency, on the anal, tail, pelvic, and pectoral fins. Prevalence generally ranged from 15 to 70 and intensity from 1 to 10. The greatest number of copepods on a single host was 44. The copepod Neoergasilus japonicus appears to disperse over long distances rather quickly, spreading across Europe in 20 yr and then moving on to North America over a span of 10 yr. Its main vehicle of transport and introduction into the Great Lakes is probably exotic fish hosts associated with the fish-culture industry.

Hudson, Patrick L.; Bowen, Charles A., II

2002-01-01

147

Development and application of a sublethal toxicity test to PAH using marine harpacticoid copepods. Final report  

SciTech Connect

This research project was designed to improve the understanding of the acute and sublethal effects of PAHs to benthic invertebrates. Sublethal bioassay protocols for benthic harpacticoid copepods were developed, and two species of harpacticoids were exposed to a range of concentrations of sediment-amended PAHs; the single compounds fluoranthene and phenanthrene as well as a complex mixture (diesel fuel). The harpacticoid copepods Schizopera knabeni and Nitocra lacustris were tested using several bioassay approaches. Reproductive assays, feeding assays and avoidance tests were conducted in addition to lethal tests for S. knabeni. Species-specific differences in sensitivity were detected. Early life history stages were much more sensitive than adults in one species but not in the other. Concentrations of PAH as low as 26 micrograms PAH decreased copepod offspring production, egg hatching success, and embryonic and early-stage development, demonstrating the high sensitivity of life history-related endpoints. In addition, grazing on microalgae was significantly impaired at concentrations as low as 20 micrograms/g PAH after short exposures (<30 h). Finally it was demonstrated that harpacticoids can actively avoid contamination.

Fleeger, J.W.; Lotufo, G.R.

1999-01-01

148

Heat shock protein expression during stress and diapause in the marine copepod Calanus finmarchicus.  

PubMed

Calanoid copepods, such as Calanus finmarchicus, are a key component of marine food webs. C. finmarchicus undergo a facultative diapause during juvenile development, which profoundly affects their seasonal distribution and availability to their predators. The current ignorance of how copepod diapause is regulated limits understanding of copepod population dynamics, distribution, and ecosystem interactions. Heat shock proteins (Hsps) are a superfamily of molecular chaperones characteristically upregulated in response to stress conditions and frequently associated with diapause in other taxa. In this study, 8 heat shock proteins were identified in C. finmarchicus C5 copepodids (Hsp21, Hsp22, p26, Hsp90, and 4 forms of Hsp70), and expression of these transcripts was characterized in response to handling stress and in association with diapause. Hsp21, Hsp22, and Hsp70A (cytosolic subfamily) were induced by handling stress. Expression of Hsp70A was also elevated in shallow active copepodids relative to deep diapausing copepodids, which may reflect induction of this gene by varied stressors in active animals. In contrast, expression of Hsp22 was elevated in deep diapausing animals; Hsp22 may play a role both in short-term stress responses and in protecting proteins from degradation during diapause. Expression of most of the Hsps examined did not vary in response to diapause, perhaps because the diapause of C. finmarchicus is not associated with the extreme environmental conditions (e.g., freezing and desiccation) experienced by many other taxa, such as overwintering insects or Artemia cysts. PMID:21419129

Aruda, Amalia M; Baumgartner, Mark F; Reitzel, Adam M; Tarrant, Ann M

2011-05-01

149

First record of Neoergasilus japonicus (Poecilostomatoida: Ergasilidae), a parasitic copepod new to the Laurentian Great Lakes.  

PubMed

The parasitic copepod Neoergasilus japonicus, native to eastern Asia, was first collected from 4 species of fish (fathead minnow, Pimephales promelas; largemouth bass, Micropterus salmoides; pumpkinseed sunfish, Lepomis gibbosus; and yellow perch, Perca flavescens) in July 1994 in Saginaw Bay, Lake Huron, Michigan. Further sampling in the bay in 2001 revealed infections on 7 additional species (bluegill, Lepomis macrochirus; carp, Cyprinus carpio; channel catfish, Ictalurus punctatus; goldfish, Carassius auratus; green sunfish, Lepomis cyanellus; rock bass, Ambloplites rupestris; and smallmouth bass, Micropterus dolomieu). An additional 21 species examined in 2001 were devoid of the parasite. A limited collection of fish from Lake Superior (n = 8) and Lake Michigan (n = 46) in 1994 showed no infection. Neoergasilus japonicus is most frequently found attached to the dorsal fin and, in decreasing frequency, on the anal, tail, pelvic, and pectoral fins. Prevalence generally ranged from 15 to 70 and intensity from 1 to 10. The greatest number of copepods on a single host was 44. The copepod Neoergasilus japonicus appears to disperse over long distances rather quickly, spreading across Europe in 20 yr and then moving on to North America over a span of 10 yr. Its main vehicle of transport and introduction into the Great Lakes is probably exotic fish hosts associated with the fish-culture industry. PMID:12197110

Hudson, Patrick L; Bowen, Charles A

2002-08-01

150

The taxonomy and distribution of the planktonic copepoda from Brazos County, Texas  

E-print Network

in southern Texas. ~clo s vernalis was the most hbundant copepod found. Erickson (1952) found that the largest num- bers of diaptomid and cyclopoid adults occurred during the fall and early. summer. Diaptomids were present only during the summer while... in southern Texas. ~clo s vernalis was the most hbundant copepod found. Erickson (1952) found that the largest num- bers of diaptomid and cyclopoid adults occurred during the fall and early. summer. Diaptomids were present only during the summer while...

Rennie, Thomas Howard

2012-06-07

151

The fluid physics of signal perception by mate-tracking copepods.  

PubMed Central

Within laboratory-induced swarms of the marine copepod Temora longicornis, the male exhibits chemically mediated trail-following behaviour, concluding with fluid mechanical provocation of the mate-capture response. The location and structure of the invisible trail were determined by examining the specific behaviour of the female copepods creating the signal, the response of the male to her signal, and the fluid physics of signal persistence. Using the distance of the mate-tracking male from the ageing trail of the female, we estimated that the molecular diffusion coefficient of the putative pheromonal stimulant was 2.7 x 10(-5) cm2 s-1, or 1000 times slower than the diffusion of momentum. Estimates of signal strength levels, using calculations of diffusive properties of odour trails and attenuation rates of fluid mechanical signals, were compared to the physiological and behavioural threshold detection levels. Males find trails because of strong across-plume chemical gradients; males sometimes go the wrong way because of weak along-plume gradients; males lose the trail when the female hops because of signal dilution; and mate-capture behaviour is elicited by suprathreshold flow signals. The male is stimulated by the female odour to accelerate along the trail to catch up with her, and the boundary layer separating the signal from the chemosensitive receptors along the copepod antennule thins. Diffusion times, and hence reaction times, shorten and behavioural orientation responses can proceed more quickly. While 'perceptive' distance to the odour signal in the trail or the fluid mechanical signal from the female remains within 1-2 body lengths (< 5 mm), the 'reactive' distance between males and females was an order of magnitude larger. Therefore, when nearest-neighbour distances are 5 cm or less, as in swarms of 10(4) copepods m-3, mating events are facilitated. The strong similarity in the structure of mating trails and vortex tubes (isotropic, millimetre-centimetre scale, 10:1 aspect ratio, 10s persistence), indicates that these trails are constrained by the same physical forces that influence water motion in a low Reynolds number fluid regime, where viscosity limits forces to the molecular scale. The exploratory reaches of mating trails appear inscribed within Kolmogorov eddies and may represent a measure of eddy size. Biologically formed mating trails, however, are distinct in their flow velocity and chemical composition from common small-scale turbulent features; and mechanoreceptive and chemoreceptive copepods use their senses to discriminate these differences. Zooplankton are not aimless wanderers in a featureless environment. Their ambit is replete with clues that guide them in their efforts for survival in the ocean. PMID:9652126

Yen, J; Weissburg, M J; Doall, M H

1998-01-01

152

Intraspecific Differences in Lipid Content of Calanoid Copepods across Fine-Scale Depth Ranges within the Photic Layer  

PubMed Central

Copepods are among the most abundant and diverse groups of mesozooplankton in the world's oceans. Each species has a certain depth range within which different individuals (of the same life stage and sex) are found. Lipids are accumulated in many calanoid copepods for energy storage and reproduction. Lipid content in some species increases with depth, however studies so far focused mostly on temperate and high-latitude seasonal vertically migrating copepods and compared lipid contents among individuals either from coarse layers or between diapausing, deep-dwelling copepods and individuals found in the photic, near-surface layer. Here we examined whether lipid contents of individual calanoid copepods of the same species, life stage/sex differ between finer depth layers within the upper water column of subtropical and Arctic seas. A total of 6 calanoid species were collected from samples taken at precise depths within the photic layer in both cold eutrophic and warm oligotrophic environments using SCUBA diving, MOCNESS and Multinet. Measurements of lipid content were obtained from digitized photographs of the collected individuals. The results revealed significant differences in lipid content across depth differences as small as 12–15 meters for Mecynocera clausi C5 and Ctenocalanus vanus C5 (Red Sea), Clausocalanus furcatus males and two clausocalanid C5s (Mediterranean Sea), and Calanus glacialis C5 (Arctic). We suggest two possible explanations for the differences in lipid content with depth on such a fine scale: predator avoidance and buoyancy. PMID:24667529

Zarubin, Margarita; Farstey, Viviana; Wold, Anette; Falk-Petersen, Stig; Genin, Amatzia

2014-01-01

153

Trophic relationships of deep-sea calanoid copepods from the benthic boundary layer of the Santa Catalina Basin, California  

NASA Astrophysics Data System (ADS)

Benthopelagic zooplankton were collected and preserved in situ in the benthic boundary layer of the Santa Catalina Basin, using a multiple sampling opening-closing net system attached to the DSRV Alvin. Gut content analysis performed with transmission electron microscopy (TEM) showed that the majority of benthopelagic calanoid copepods examined were predominantly detritivores. They had ingested detritus and associated bacteria, including metal-precipitating bacteria; no attached enteric bacteria were observed in the copepods' guts. The gut particles indicated generalized feeding and qualitatively resembled material present in the environment at the time of collection, i.e. suspended particles, large fecal pellets, particles from the surface layer of the sediment, and phaeodia of phaeodarian radiolarians. TEM was necessary for identifying some of the amorphous material in copepod guts as either digested tissue or detrital material; some of the amorphous material was unidentifiable even with the resolution of TEM. TEM was also essential for detecting metal-precipitating bacteria and their capsules from the copepod guts and from particles in the water. Because they ingest metal-precipitating bacteria, detritivorous copepods may influence the distribution of metals in the ocean.

Gowing, Marcia M.; Wishner, Karen F.

1986-07-01

154

Effects of advection on the seasonal abundance patterns of three species of planktonic calanoid copepods in Dabob Bay, Washington  

NASA Astrophysics Data System (ADS)

The copepodid stage abundances of Calanus marshallae, Calanus pacificus and Metridia pacifica in Dabob Bay, Washington were followed through two years. Based on the species' life histories, vertical distributions, abundances inside and outside the bay, and the hydrographic setting, times when advection was important were explored. During the first study-year, 1973, advection acted to keep the copepod concentrations inside and outside Dabob Bay similar through the early summer. During the summer, a period of very little advective exchange, the copepod concentrations diverged at the two stations. In the fall, when advection picked up again, the copepod concentrations at the two stations once again became similar. During the summer of the other study-year, 1982, flow of deep water into Dabob Bay occurred. This may have caused some of the differences observed in the abundances of the copepods during the summer of 1982 vs 1973. Due in part to the advective events, the seasonal abundance patterns of the copepods could not be predicted based upon their locally expressed life history patterns. The most striking example of this was C. pacificus. Its population decreased during the spring and increased during the fall, despite having its major reproductive peak in the spring. Advective effects clearly contributed to this.

Osgood, Kenric E.; Frost, Bruce W.

1996-08-01

155

Effect of Grazing-Mediated Dimethyl Sulfide (DMS) Production on the Swimming Behavior of the Copepod Calanus helgolandicus  

PubMed Central

Chemical interactions play a fundamental role in the ecology of marine foodwebs. Dimethyl sulfide (DMS) is a ubiquitous marine trace gas that acts as a bioactive compound by eliciting foraging behavior in a range of marine taxa including the copepod Temora longicornis. Production of DMS can rapidly increase following microzooplankton grazing on phytoplankton. Here, we investigated whether grazing-induced DMS elicits an increase in foraging behavior in the copepod Calanus helgolandicus. We developed a semi-automated method to quantify the effect of grazing-mediated DMS on the proportion of the time budget tethered females allocate towards slow swimming, typically associated with feeding. The pooled data showed no differences in the proportion of the 25 min time budget allocated towards slow swimming between high (23.6 ± 9.74%) and low (29.1 ± 18.33%) DMS treatments. However, there was a high degree of variability between behavioral responses of individual copepods. We discuss the need for more detailed species-specific studies of individual level responses of copepods to chemical signals at different spatial scales to improve our understanding of chemical interactions between copepods and their prey. PMID:23860240

Breckels, Mark N.; Bode, Nikolai W. F.; Codling, Edward A.; Steinke, Michael

2013-01-01

156

Distinctive mitochondrial genome of Calanoid copepod Calanus sinicus with multiple large non-coding regions and reshuffled gene order: Useful molecular markers for phylogenetic and population studies  

Microsoft Academic Search

BACKGROUND: Copepods are highly diverse and abundant, resulting in extensive ecological radiation in marine ecosystems. Calanus sinicus dominates continental shelf waters in the northwest Pacific Ocean and plays an important role in the local ecosystem by linking primary production to higher trophic levels. A lack of effective molecular markers has hindered phylogenetic and population genetic studies concerning copepods. As they

Wang Minxiao; Sun Song; Li Chaolun; Shen Xin

2011-01-01

157

Copper effects in the copepod Tigriopus angulatus Lang, 1933: natural broad tolerance allows maintenance of food webs in copper-enriched coastal areas  

Microsoft Academic Search

Abstract. Some coastal areas of northern Chile have received copper mine,tailings for more,than 60 years. At these areas, the toxic effects of copper have eliminated most intertidal seaweed and macroinvertebrate populations. However, the harpacticoid splashpool copepod Tigriopus angulatus seems unaffected, inhabiting heavily impacted sites. Because this species of copepod makes the energy of photosynthesis available to higher trophic levels, it

M. H. Medina; B. Morandi; J. A. Correa

2008-01-01

158

Copper effects in the copepod Tigriopus angulatus Lang, 1933: natural broad tolerance allows maintenance of food webs in copper-enriched coastal areas  

Microsoft Academic Search

Some coastal areas of northern Chile have received copper mine tailings for more than 60 years. At these areas, the toxic effects of copper have eliminated most intertidal seaweed and macroinvertebrate populations. However, the harpacticoid splashpool copepod Tigriopus angulatus seems unaffected, inhabiting heavily impacted sites. Because this species of copepod makes the energy of photosynthesis available to higher trophic levels,

M. H. MedinaA; B. MorandiC; J. A. CorreaD

159

Trade-Offs between Predation Risk and Growth Benefits in the Copepod Eurytemora affinis with Contrasting Pigmentation  

PubMed Central

Intraspecific variation in body pigmentation is an ecologically and evolutionary important trait; however, the pigmentation related trade-offs in marine zooplankton are poorly understood. We tested the effects of intrapopulation phenotypic variation in the pigmentation of the copepod Eurytemora affinis on predation risk, foraging, growth, metabolic activity and antioxidant capacity. Using pigmented and unpigmented specimens, we compared (1) predation and selectivity by the invertebrate predator Cercopagis pengoi, (2) feeding activity of the copepods measured as grazing rate in experiments and gut fluorescence in situ, (3) metabolic activity assayed as RNA:DNA ratio in both experimental and field-collected copepods, (4) reproductive output estimated as egg ratio in the population, and (5) total antioxidant capacity. Moreover, mitochondrial DNA (mtDNA) COI gene variation was analysed. The pigmented individuals were at higher predation risk as evidenced by significantly higher predation rate by C. pengoi on pigmented individuals and positive selection by the predator fed pigmented and unpigmented copepods in a mixture. However, the antioxidant capacity, RNA:DNA and egg ratio values were significantly higher in the pigmented copepods, whereas neither feeding rate nor gut fluorescence differed between the pigmented and unpigmented copepods. The phenotypic variation in pigmentation was not associated with any specific mtDNA genotype. Together, these results support the metabolic stimulation hypothesis to explain variation in E. affinis pigmentation, which translates into beneficial increase in growth via enhanced metabolism and antioxidant protective capacity, together with disadvantageous increase in predation risk. We also suggest an alternative mechanism for the metabolic stimulation via elevated antioxidant levels as a primary means of increasing metabolism without the increase in heat absorbance. The observed trade-offs are relevant to evolutionary mechanisms underlying plasticity and adaptation and have the capacity to modify strength of complex trophic interactions. PMID:23940745

Gorokhova, Elena; Lehtiniemi, Maiju; Motwani, Nisha H.

2013-01-01

160

The mitochondrial genomes of Amphiascoides atopus and Schizopera knabeni (Harpacticoida: Miraciidae) reveal similarities between the copepod orders Harpacticoida and Poecilostomatoida.  

PubMed

Members of subclass Copepoda are abundant, diverse, and-as a result of their variety of ecological roles in marine and freshwater environments-important, but their phylogenetic interrelationships are unclear. Recent studies of arthropods have used gene arrangements in the mitochondrial (mt) genome to infer phylogenies, but for copepods, only seven complete mt genomes have been published. These data revealed several within-order and few among-order similarities. To increase the data available for comparisons, we sequenced the complete mt genome (13,831base pairs) of Amphiascoides atopus and 10,649base pairs of the mt genome of Schizopera knabeni (both in the family Miraciidae of the order Harpacticoida). Comparison of our data to those for Tigriopus japonicus (family Harpacticidae, order Harpacticoida) revealed similarities in gene arrangement among these three species that were consistent with those found within and among families of other copepod orders. Comparison of the mt genomes of our species with those known from other copepod orders revealed the arrangement of mt genes of our Harpacticoida species to be more similar to that of Sinergasilus polycolpus (order Poecilostomatoida) than to that of T. japonicus. The similarities between S. polycolpus and our species are the first to be noted across the boundaries of copepod orders and support the possibility that mt-gene arrangement might be used to infer copepod phylogenies. We also found that our two species had extremely truncated transfer RNAs and that gene overlaps occurred much more frequently than has been reported for other copepod mt genomes. PMID:24389499

Easton, Erin E; Darrow, Emily M; Spears, Trisha; Thistle, David

2014-03-15

161

Trade-offs between predation risk and growth benefits in the copepod Eurytemora affinis with contrasting pigmentation.  

PubMed

Intraspecific variation in body pigmentation is an ecologically and evolutionary important trait; however, the pigmentation related trade-offs in marine zooplankton are poorly understood. We tested the effects of intrapopulation phenotypic variation in the pigmentation of the copepod Eurytemora affinis on predation risk, foraging, growth, metabolic activity and antioxidant capacity. Using pigmented and unpigmented specimens, we compared (1) predation and selectivity by the invertebrate predator Cercopagis pengoi, (2) feeding activity of the copepods measured as grazing rate in experiments and gut fluorescence in situ, (3) metabolic activity assayed as RNA:DNA ratio in both experimental and field-collected copepods, (4) reproductive output estimated as egg ratio in the population, and (5) total antioxidant capacity. Moreover, mitochondrial DNA (mtDNA) COI gene variation was analysed. The pigmented individuals were at higher predation risk as evidenced by significantly higher predation rate by C. pengoi on pigmented individuals and positive selection by the predator fed pigmented and unpigmented copepods in a mixture. However, the antioxidant capacity, RNA:DNA and egg ratio values were significantly higher in the pigmented copepods, whereas neither feeding rate nor gut fluorescence differed between the pigmented and unpigmented copepods. The phenotypic variation in pigmentation was not associated with any specific mtDNA genotype. Together, these results support the metabolic stimulation hypothesis to explain variation in E. affinis pigmentation, which translates into beneficial increase in growth via enhanced metabolism and antioxidant protective capacity, together with disadvantageous increase in predation risk. We also suggest an alternative mechanism for the metabolic stimulation via elevated antioxidant levels as a primary means of increasing metabolism without the increase in heat absorbance. The observed trade-offs are relevant to evolutionary mechanisms underlying plasticity and adaptation and have the capacity to modify strength of complex trophic interactions. PMID:23940745

Gorokhova, Elena; Lehtiniemi, Maiju; Motwani, Nisha H

2013-01-01

162

A COMPARATIVE ASSESSMENT OF AZINPHOSMETHYL BIOACCUMULATION AND TOXICITY IN TWO ESTUARINE MEIOBENTHIC HARPACTICOID COPEPODS  

Microsoft Academic Search

Abstract—Aqueous, pore-water, and whole-sediment bioassays were conducted with meiobenthic copepods with different infaunal lifestyles to assess the acute and chronic toxicity of the organophosphorous pesticide azinphosmethyl,(APM) and its bioaccumulation potential in sediments. Biota sediment,accumulation,factors were an order of magnitude,higher for the deeper burrowing,Amphiascus tenuiremis (26.6) than the epibenthic Microarthridion littorale (2.2). The female,A. tenuiremis APM median,lethal concentration (LC50; 3.6 mg\\/L)

Susan L. Klosterhaus; Lisa M. DiPinto; G. Thomas Chandler

2003-01-01

163

Combined toxicity of copper, cadmium, zinc, lead, nickel, and chrome to the copepod Tisbe holothuriae  

SciTech Connect

In recent years much work has been concerned with the determination of various contaminants in the environment and with the establishment of the toxicity of these compounds to marine animals. Heavy metals are of increasing concern as pollutants of marine and especially coastal environments. Mixtures of heavy metals may produce unexpected effects. The purpose of this study was to determine the acute toxicity of six heavy metals (Cu, Cd, Zn, Pb, Ni and Cr) to the marine copepod Tisbe holothuriae Humes and to see whether there is any interaction between these metals, when applied jointly.

Verriopoulos, G.; Dimas, S.

1988-09-01

164

REPRODUCTIVE AND DEVELOPMENTAL EFFECTS OF ATRAZINE ON THE ESTUARINE MEIOBENTHIC COPEPOD AMPHIASCUS TENUIREMIS  

Microsoft Academic Search

Abstract—Atrazine is one of the most widely used herbicides in the United States. Atrazine concentrations,in coastal environments chronically range from 90 ng\\/L to 46 mg\\/L, with rare but measured concentrations near 60 mg\\/L at edge-of-field conditions. Chronic atrazine effects on estuarine benthos exposed,to environmentally,relevant concentrations,are unknown.,The purpose of this research was,to assess atrazine reproductive,and,developmental,effects over multiple-generation exposures,of the copepod,Amphiascus tenuiremis.

Adriana C. Bejarano; G. Thomas Chandler

2003-01-01

165

Impact of the diatom oxylipin 15S-HEPE on the reproductive success of the copepod Temora stylifera  

Microsoft Academic Search

The copepod Temora stylifera was fed with the pennate diatom Pseudo-nitzschia delicatissima for 15 days. This diatom does not produce polyunsaturated aldehydes (PUAs) but only synthesizes other oxylipins such as the\\u000a hydroxyacid (5Z,8Z,11Z,13E,15S,17Z)-15-hydroxy-5,8,11,13,17-eicosapentaenoic acid (15S-HEPE). Effects of this monoalgal diet\\u000a were compared to copepods fed with the PUA-producing diatom Skeletonema marinoi and the control dinoflagellate Prorocentrum minimum which does not produce

Adrianna Ianora; Giovanna Romano; Ylenia Carotenuto; Francesco Esposito; Vittoria Roncalli; Isabella Buttino; Antonio Miralto

2011-01-01

166

Parasitization of a hydrothermal vent limpet (Lepetodrilidae, Vetigastropoda) by a highly modified copepod (Chitonophilidae, Cyclopoida).  

PubMed

The limpet Lepetodrilus fucensis McLean is very abundant at hydrothermal vents on the Juan de Fuca and Explorer Ridges in the northeast Pacific Ocean. This limpet is parasitized by an undescribed chitonophilid copepod throughout the limpet's range. The parasite copepodite enters the mantle cavity and attaches to the afferent branchial vein. The initial invasive stage is a vermiform endosome within the vein that develops an extensive rootlet system causing an enlargement of the afferent branchial vein. Subsequently, an ectosomal female body grows outside the vein to sizes up to 2 mm in width. Once a dwarf male attaches, egg clusters form and nauplii are released. In over 3000 limpets examined from 30 populations, prevalence averaged about 5% with localized infections in female limpets over 25%. After the establishment of limpet populations at new vents, copepod prevalence increased over the succeeding months to 3 years. Host effects were marked and included castration of both sexes and deterioration in gill condition which affected both food acquisition and the gill symbiont. There was a significantly greater parasite prevalence in larger females which likely modifies the reproductive and competitive success of local host populations. PMID:18664307

Tunnicliffe, V; Rose, J M; Bates, A E; Kelly, N E

2008-09-01

167

Active avoidance from a crude oil soluble fraction by an Andean paramo copepod.  

PubMed

Several oil spills due to ruptures in the pipeline oil systems have occurred at the Andean paramo. A sample of this crude oil was mixed with water from a nearby Andean lagoon and the toxicity of the soluble fraction was assessed through lethal and avoidance assays with a locally occurring copepod (Boeckella occidentalis intermedia). The integration of mortality and avoidance aimed at predicting the immediate decline of copepod populations facing an oil leakage. The 24-h median lethal PAH concentration was 42.7 (26.4-91.6) µg L(-1). In the 12-h avoidance assay, 30% avoidance was recorded at the highest PAH concentration (19.4 µg L(-1)). The mortality at this PAH concentration would be of 25% and, thus, the population immediate decline would be of 55%. The inclusion of non-forced exposure testing with the quantification of the avoidance response in environmental risk assessments is, therefore, supported due to underestimation of the lethal assays. PMID:24898412

Araújo, Cristiano V M; Moreira-Santos, Matilde; Sousa, José P; Ochoa-Herrera, Valeria; Encalada, Andrea C; Ribeiro, Rui

2014-09-01

168

Cryptic diversity of the 'cosmopolitan' harpacticoid copepod Nannopus palustris: genetic and morphological evidence.  

PubMed

Nannopus palustris Brady, 1880 is a free-living widely distributed harpacticoid copepod, which has been formerly assumed to be a single, cosmopolitan but highly variable species. We compared several geographically distant N. palustris populations in terms of their morphology and genetics. Populations from the White Sea (WS), the North Sea (NS), the Black Sea (BS) and two sympatric morphs from South Carolina, USA (SC notched and SC straight morphs), were considered. The NS, BS and to a lesser extent SC notched specimens were morphologically similar and partly coincided to the 'canonical' description of the species. By contrast, WS population showed remarkable anatomical and morphometric peculiarities that correspond to some earlier descriptions. Genetic analyses of mitochondrial (cytochrome b) and nuclear (28S rDNA) genes demonstrated the significant distinctness among WS, both SC and (NS+BS) populations, the latter two being genetically indistinguishable. Concordance between mitochondrial and nuclear gene trees and morphological data supports that N. palustris is in fact composed of several pseudo-sibling species, which are genetically and morphologically divergent. Neither correlation between genetic divergence and geographical distance nor significant intrapopulation diversity was found for these species. Taxonomic status, distribution and phylogenetic relationships of the species within the Nannopus genus need to be reconsidered. A further subdivision of species complexes might have important implications for the analysis of biodiversity of benthic copepods and consequently for the interpretation of their (species-specific) ecological function. PMID:22989315

Garlitska, Lesya; Neretina, Tatyana; Schepetov, Dimitry; Mugue, Nikolai; De Troch, Marleen; Baguley, Jeffrey G; Azovsky, Andrey

2012-11-01

169

Copepod behavior in thin layers of attractive and deterrent chemical cues  

NASA Astrophysics Data System (ADS)

Recent studies have shown that the oceanographic distribution of mobile zooplankton can be attributed, at least in part, to foraging and aggregative behaviors. A laboratory system was developed to test the cues that induce these behaviors. The system mimics thin layer structure in the ocean, and the research has focused on calanoid copepods, specifically Temora longicornis and Acartia tonsa. Responses are directly observed as copepod cultures are subjected to different attractive and deterrent chemical cues, such as phytoplankton (food) and harmful algal bloom metabolites. Behaviors are quantified using three behavioral markers: proportional residence time in the thin layer, swimming speed, and turn frequency. These three markers are measured using video-based observation, which quantifies path kinematics and swimming behavior. Previous experiments have shown that attractive chemical exudates elicite behaviors such as increased swimming speed and excited area-restricted search behavior. Thus, understanding how zooplankton behave in response to chemicals from toxic species will extend our understanding of zooplankton interaction with thin layers and the potential consequences for population dynamics, nutrient cycling, and biodiversity in coastal and pelagic ecosystems.

Lynch, M.; Webster, D. R.; Weissburg, M. J.; Yen, J.

2008-12-01

170

Potential fitness trade-offs for thermal tolerance in the intertidal copepod Tigriopus californicus.  

PubMed

Thermal adaptation to spatially varying environmental conditions occurs in a wide range of species, but what is less clear is the nature of fitness trade-offs associated with this temperature adaptation. Here, populations of the intertidal copepod Tigriopus californicus are examined at both local and latitudinal scales to determine whether these populations have evolved differences in their survival under high temperature stress. A clear pattern of increasing high temperature stress tolerance is seen with decreasing latitude, consistent with temperature adaptation. Additionally, there is also evidence for significant variation in thermal tolerance on a smaller scale. The competitive fitness of pairs of northern and southern copepod populations were also examined under a series of lower, more moderate temperatures. These fitness assays show that the southern populations that have the best survival under extreme high temperatures have lowered competitive fitness at the lower temperatures tested, whereas the fitness of the southern populations exceeded that of the northern populations at the highest temperatures tested. Combined, these results suggest that there may be evolutionary trade-offs between performance at high and stressful temperatures and fitness at moderate temperatures in this species. PMID:20394668

Willett, Christopher S

2010-09-01

171

Hybrid breakdown weakens under thermal stress in population crosses of the copepod Tigriopus californicus.  

PubMed

The outcome of hybridization can be impacted by environmental conditions, which themselves can contribute to reproductive isolation between taxa. In crosses of genetically divergent populations, hybridization can have both negative and positive impacts on fitness, the balance between which might be tipped by changes in the environment. Genetically divergent populations of the intertidal copepod Tigriopus californicus have been shown to differ in thermal tolerance at high temperatures along a latitudinal gradient. In this study, a series of crosses were made between pairs of genetically divergent populations of T. californicus, and the thermal tolerance of these hybrids was tested. In most cases, the first-generation hybrids had relatively high thermal tolerance and the second-generation hybrids were not generally reduced below the less-tolerant parental population for high temperature tolerance. This pattern contrasts with previous studies from crosses of genetically divergent populations of this copepod, which often shows hybrid breakdown in these second-generation hybrids for other measures of fitness. These results suggest that high temperature stress could either increase the positive impacts of hybridization or decrease the negative impacts of hybridization resulting in lowered hybrid breakdown in these population crosses. PMID:22016434

Willett, Christopher S

2012-01-01

172

Characterization of the glutamate dehydrogenase gene and its regulation in a euryhaline copepod.  

PubMed

Glutamate dehydrogenase (GDH) plays a key role in the metabolism of free amino acids (FAA) in crustaceans and other metazoans. Glutamate synthesized by GDH via reductive amination is the amino group donor for alanine synthesis and the precursor required for proline synthesis. Since both proline and alanine are important intracellular osmolytes in many marine invertebrates, GDH has been widely implicated as playing a central role in response to hyperosmotic stress in these organisms. We have isolated the gene encoding a GDH homolog from the euryhaline copepod Tigriopus californicus and examined the regulation of GDH under salinity stress. The gene encodes a protein of 557 residues with 76% amino acid identity with Drosophila melanogaster GDH. The gene encodes an N-terminal mitochondrial signal sequence peptide. Only a single intron of 71 bp was found in the GDH gene in T. californicus when genomic sequences and cDNA sequences were compared. The levels of GDH mRNA do not increase during hyperosmotic stress in this copepod. The effects of salt and hyperosmotic stress on GDH enzyme activity were also investigated. GDH activities decrease with increasing NaCl concentrations in in vitro enzyme assays, while live animals exposed to hyperosmotic stress showed no change in GDH enzyme activities. Combined, these results indicate that GDH transcription and enzyme activity do not appear to function in the regulation of alanine and proline accumulation during hyperosmotic stress in T. californicus. The manner in which this important physiological process is regulated remains unknown. PMID:12892755

Willett, Christopher S; Burton, Ronald S

2003-08-01

173

Relationship between specific dynamic action and protein deposition in calanoid copepods.  

PubMed

The link between specific dynamic action (SDA) and protein deposition was investigated in copepodites stage V of two calanoid copepod species, the neritic Acartia tonsa and the oceanic Calanus finmarchicus. This was done by measuring respiration before, during, and after a specific feeding period and measuring the incorporation of carbon into proteins. These were also measured on individuals incubated with cycloheximide, an antibiotic that inhibits protein synthesis. The cycloheximide treatment significantly diminished the magnitude of SDA in both A. tonsa and C. finmarchicus, and inhibited carbon incorporation into protein in both species. This provides evidence that the rate at which protein deposition takes place greatly affects the magnitude of SDA. The specific respiration rates of both starving and feeding copepods were generally higher in A. tonsa than in C. finmarchicus. This influenced SDA, the magnitude of SDA normalised to an 8 h feeding period being threefold higher in A. tonsa (78.7+/-25.7 nlO(2) µgC(-1)) than in C. finmarchicus (27.5+/-11.6 nlO(2) µgC(-1)). This difference may arise due to differences in energy allocation in the organisms of the copepodite V stage of the two species. In this stage C. finmarchicus deposits large quantities of storage lipids, predominately wax esters, whereas A. tonsa deposits proteins during somatic growth. PMID:10699208

Thor

2000-03-15

174

Grazing rates of the copepods Calanus glacialis and C. finmarchicus in arctic waters of the Barents Sea  

Microsoft Academic Search

Natural feeding rates of Copepodite Stages IV and V, and adult female Calanus glacialis (Jaschnov) and Copepodite Stage V and adult female C. finmarchicus (Gunnerus) were estimated using fluorescence analysis of gut contents. Measurements were made on copepods sampled from arctic waters east of Svalbard (Barents Sea) during the spring phytoplankton increase, in the period from 27 May to 13

K. S. Tande; U. Båmstedt

1985-01-01

175

Life history and biogeography of Calanus copepods in the Arctic Ocean: An individual-based modeling study  

E-print Network

Life history and biogeography of Calanus copepods in the Arctic Ocean: An individual-based modeling Ocean and its marginal seas, two are expatriates in the Arctic (Calanus finmarchicus and Calanus to penetrate, survive, and colonize the Arctic Ocean under present conditions of temperature, food availability

Chen, Changsheng

176

Phylogeny of the freshwater copepod Mesocyclops (Crustacea: Cyclopidae) based on combined molecular and morphological data, with notes on biogeography  

E-print Network

Phylogeny of the freshwater copepod Mesocyclops (Crustacea: Cyclopidae) based on combined molecular analyses Freshwater crustaceans Mesocyclops Nuclear DNA 18S rDNA ITS2 Morphology Biogeography a b s t r a c in this freshwater, predominantly (sub)tropical genus. Mesocyclops darwini was the single taxon whose relationships

Schulte, Jim

177

The effect of salinity on the acute toxicity of total and free cadmium to a Chesapeake Bay copepod and fish  

Microsoft Academic Search

The objective of this study was to determine the influence of a range of salinities (5, 15 and 25 ppt) on the acute toxicity of total and free cadmium to the sheepshead minnow (Cyprinodon variegatus) larvae and the copepod Eurytemora affinis nauplii. Data were analysed to determine if the acute toxicity (96 h LC50) was different among salinities for the

Lenwood W. Hall; Michael C. Ziegenfuss; Ronald D. Anderson; Brent L. Lewis

1995-01-01

178

POPULATION DYNAMICS AND DEMOGRAPHY OF AN ESTUARINE COPEPOD (PSEUDODIAPTOMUS EESSEI) IN LAKE SIBAYA, A SUBTROPICAL FRESHWATER COASTAL LAKE  

Microsoft Academic Search

Population size and stage structure of Pseudodiaptomus hessei (Mrázek) was studied over 27 months at a single site in subtropical Lake Sibaya. Population density varied seasonally from about 1 to 4 individuals per litre, but a fairly stable population structure was maintained by continuous breeding of this strongly multivoltine copepod. Embryonic durations were determined at several temperatures and used to

R C Hart

1981-01-01

179

EFFECTS OF SEDIMENT-BOUND RESIDUES OF THE PYRETHROID INSECTICIDE FENVALERATE ON SURVIVAL AND REPRODUCTION OF MEIOBENTHIC COPEPODS  

EPA Science Inventory

Pure microcosm-cultured populations of benthic copepods were established from pristine or pesticide-impacted Spartina marsh creeks and used as efficient bioassay groups to assess lethal and sublethal effects of sediment-bound pesticide residues. espite a broad data base showing e...

180

Tolerance and genetic relatedness of three meiobenthic copepod populations exposed to sediment-associated contaminant mixtures: Role of environmental history  

SciTech Connect

Meiobenthic copepod populations (Microarthridion littoral) were collected from three South Carolina, USA, estuaries having different pollution stress histories (i.e., pristine sediments, high polycyclic aromatic hydrocarbon [PAH] sediments, high metals/moderate PAH sediments) and then assayed for survival and reproductive output in 14-d exposures to pristine and heavily PAH/metals-contaminated sediment mixture exhibited differential survival and reproductive outputs as a function of previous environmental histories and whether genetic relatedness among populations measured as DNA sequences of the mitochondrial gene, cytochrome apoenzyme b, were linked to copepod contaminant tolerance. Overall, adult survival and reproductive success in contaminated sediments were significantly reduced relative to controls for all three populations irrespective of environmental histories. Differential resistance to sediment-contaminant mixtures by the two copepod populations inhabiting the contaminated sites was not found, despite their previous exposures to mixed contaminants at {Sigma}PAH and {Sigma}Metal concentrations of 7,287 to 2,467 ng/g dry wt and 461 to 3,497 {micro}g/g, respectively. Significant genetic differentiation, however, was found between copepod populations from the control and the two contaminated sites. Generally, cross-population survival and reproductive outputs were not significantly different and could not be linked to genetic differentiation at the population level.

Kovatch, C.E.; Schizas, N.V.; Chandler, G.T.; Coull, B.C.; Quattro, J.M.

2000-04-01

181

Seasonal fluctuations of the copepod resting egg bank in the middle Seine estuary, France: Impact on the nauplii recruitment  

NASA Astrophysics Data System (ADS)

In order to determine the role of resting eggs in the plankton dynamic of the main calanoid copepods species of the Seine estuary, 30 sediment cores of approx. 10 cm were sampled over one year in the subtidal area of the middle Seine estuary (France). The resting eggs of calanoid copepods were extracted from the 10 surficial cm of sediment, quantified (abundance), and then incubated, either immediately after extraction or after one month at low temperature, in order to determine the hatching success, the type of eggs (quiescent, diapause) and species. Viable resting eggs were found, with total abundances ranging from 0.06 ± 0.05 to 2.33 ± 1.40 × 107 eggs m-3 and higher values in early summer and mid autumn. This study indicated that the production of resting eggs may act in both short-term (continuous emergence, reinforcement of post winter production) and long-term survival (formation of an egg bank) for the key copepod species of the Seine estuary (Acartidae, Eurytemora affinis and Temora longicornis). With a hatching success of 3.5%, 11,644, 710,267 and 52,397 nauplii m-3 month-1 were estimated emerging from surficial sediments respectively for Acartia spp., T. longicornis and E. affinis; demonstrating the significant role of resting eggs in the population dynamic of the main calanoid copepods species in the Seine estuary.

Glippa, Olivier; Denis, Lionel; Lesourd, Sandric; Souissi, Sami

2014-04-01

182

MODIFICATION OF THE FEEDING BEHAVIOR OF MARINE COPEPODS BY SUB-LETHAL CONCENTRATIONS OF WATER-ACCOMMODATED FUEL OIL  

EPA Science Inventory

The feeding behaviors of Acartia clausi and A. tonsa were measured in samples of water containing low levels of a water-accommodated fraction of No. 2 fuel oil. The copepods fed normally at a hydrocarbon concentration of 70 micrograms/l, but their feeding behavior was altered bot...

183

Spring diel vertical distribution of copepod abundances and diversity in the open Central Tyrrhenian Sea (Western Mediterranean)  

NASA Astrophysics Data System (ADS)

Spring vertical distribution of copepod communities was studied every 6 h during a 24 h cycle, using the BIONESS multinet, to evaluate diel vertical migration (DVM) of the key species in a Central Tyrrhenian Sea station (from 0 to 2000 m). Similar abundance trends were detected for the four sampling times. Highest abundances were recorded between 20-40 and 60-80 m depth, at midnight and in the morning. In epipelagic layers, highest diversity occurred between 20 and 100 m in the morning and at midday, and from 100-200 m in the afternoon and 300-400 m at midnight, in mesopelagic ones. DVM involved mostly the 60 and 300 m depth interval. Epipelagic and mesopelagic copepods co-occurred in this stratum, so diel changes in species composition and diversity induced shifts in the slope of the highest k-dominance curves. The epipelagic Neocalanus gracilis and the intermediate Eucalanus elongatus copepod species showed a bimodal distribution. Only the shallower population of E. elongatus exhibited significant DVM. Few other copepod species showed significant DVM (the epipelagic Scolecithricella dentata and the subsurface Corycaeus furcifer and Pleuromamma gracilis), confirming previous information about the presence of few strong migrants in the Mediterranean Sea. Lucicutia longiserrata, Gaetanus kruppi and Monacilla typica with their copepodites were the only species dominant below 600 m depth and they were not affected by DVM.

Brugnano, C.; Granata, A.; Guglielmo, L.; Zagami, G.

2012-12-01

184

Escape strategies in co-occurring calanoid copepods Daniel S. Burdick, Daniel K. Hartline, and Petra H. Lenz1  

E-print Network

Escape strategies in co-occurring calanoid copepods Daniel S. Burdick, Daniel K. Hartline contrasting hydrodynamic stimuli. Species-specific patterns in escape behavior included quantitative differences in performance to each stimulus type. Using high-speed video, we compared escape reactions

Hartline, Daniel K.

185

The Role of the Predaceous Copepod Parabroteas Sarsi in the Pelagic Food Web of a Large Deep Andean Lake  

Microsoft Academic Search

Parabroteas sarsi is a predaceous calanoid copepod that inhabits both shallow temporary fishless ponds and deep fish lakes of Patagonia and Antarctica. The aim of this study was to analyse the effect of P. sarsi on the plankton structure of a deep Andean lake (>100 m depth) and the zooplankton vertical distribution in order to asses a possible vertical refuge

Mariana Reissig; Beatriz Modenutti; Esteban Balseiro; Claudia Queimaliños

2004-01-01

186

Food-web inferences of stable isotope spatial patterns in copepods and yellowfin tuna in the pelagic eastern Pacific Ocean  

E-print Network

Food-web inferences of stable isotope spatial patterns in copepods and yellowfin tuna inshore­offshore, east to west gradient in yellowfin tuna trophic position was corroborated using compound by the distribution of yellowfin tuna of different sizes, by seasonal variability at the base of the food web

Hawai'i at Manoa, University of

187

The copepod Tigriopus: a promising marine model organism for ecotoxicology and environmental genomics.  

PubMed

There is an increasing body of evidence to support the significant role of invertebrates in assessing impacts of environmental contaminants on marine ecosystems. Therefore, in recent years massive efforts have been directed to identify viable and ecologically relevant invertebrate toxicity testing models. Tigriopus, a harpacticoid copepod has a number of promising characteristics which make it a candidate worth consideration in such efforts. Tigriopus and other copepods are widely distributed and ecologically important organisms. Their position in marine food chains is very prominent, especially with regard to the transfer of energy. Copepods also play an important role in the transportation of aquatic pollutants across the food chains. In recent years there has been a phenomenal increase in the knowledge base of Tigriopus spp., particularly in the areas of their ecology, geophylogeny, genomics and their behavioural, biochemical and molecular responses following exposure to environmental stressors and chemicals. Sequences of a number of important marker genes have been studied in various Tigriopus spp., notably T. californicus and T. japonicus. These genes belong to normal biophysiological functions (e.g. electron transport system enzymes) as well as stress and toxic chemical exposure responses (heat shock protein 20, glutathione reductase, glutathione S-transferase). Recently, 40,740 expressed sequenced tags (ESTs) from T. japonicus, have been sequenced and of them, 5,673 ESTs showed significant hits (E-value, >1.0E-05) to the red flour beetle Tribolium genome database. Metals and organic pollutants such as antifouling agents, pesticides, polycyclic aromatic hydrocarbons (PAH) and polychrlorinated biphenyls (PCB) have shown reproducible biological responses when tested in Tigriopus spp. Promising results have been obtained when Tigriopus was used for assessment of risk associated with exposure to endocrine-disrupting chemicals (EDCs). Application of environmental gene expression techniques has allowed evaluation of transcriptional changes in T. japonicus with the ultimate aim of understanding the mechanisms of action of environmental stressors. Through a better understanding of toxicological mechanisms, ecotoxicologists may use this ecologically relevant species in risk assessment studies in marine systems. The combination of uses as a whole-animal bioassay and gene expression studies indicate that Tigriopus may serve as an excellent tool to evaluate the impacts of marine pollution throughout the coastal region. The purpose of this review is to illustrate the potential of using Tigriopus to fulfill the niche as an important invertebrate marine model organism for ecotoxicology and environmental genomics. In addition, the knowledge gaps and areas for further studies have also been discussed. PMID:17560667

Raisuddin, Sheikh; Kwok, Kevin W H; Leung, Kenneth M Y; Schlenk, Daniel; Lee, Jae-Seong

2007-07-20

188

Prey capture of pike Esox lucius larvae in turbid water.  

PubMed

Pike Esox lucius larvae captured fewer calanoid and cyclopoid copepods in turbid than in clear water, whereas no differences were detected in feeding rates on Daphnia longispina. Decreased capture of copepods may lead to lower growth and survival of E. lucius larvae in turbid areas, in particular, if cladocerans are scarce. PMID:20557612

Salonen, M; Engström-Ost, J

2010-06-01

189

Ontogenic changes of amino acid composition in planktonic crustacean species  

Microsoft Academic Search

Changes in amino acid composition (AAC) during ontogeny of some planktonic crustacean species commonly found in fresh and brackish coastal waters were compared. For these comparisons two calanoid copepods (Eurytemora velox and Calanipeda aquae-dulcis), two cyclopoid copepods (Diacyclops bicuspidatus odessanus and Acanthocyclops robustus) and two Daphnia (Daphnia pulicaria and Daphnia magna) species were selected. A discriminant analysis was performed to

Sandra Brucet; Dani Boix; Rocìo López-Flores; Anna Badosa; Xavier D. Quintana

2005-01-01

190

Primers to block the amplification of symbiotic apostome ciliate 18S rRNA gene in a PCR-based copepod diet study  

NASA Astrophysics Data System (ADS)

Pelagic copepods play an important role in the marine food web. However, a full understanding of the ecological status of this zooplankton group depends on the careful study of their natural diets. In previous PCR-based copepod diet studies, we found many apostome ciliates that live symbiotically under the exoskeleton of the copepods, and their sequences were often over-represented in the 18S rRNA gene (18S rDNA) libraries. As a first step to address this issue, we designed three apostome ciliate 18S rDNA blocking primers, and tested their blocking efficiency against apostome ciliate 18s rDNA under various PCR conditions. Using a semi-quantitative PCR method, we optimized the conditions to efficiently amplify the 18S rDNA of the prey while simultaneously excluding the symbiotic apostome ciliates. This technique will facilitate PCR-based diet studies of copepods and other zooplankton in their natural environments.

Yi, Xiaoyan; Zhang, Huan; Liu, Guangxing

2014-05-01

191

Phylogeography of the intertidal copepod Tigriopus californicus reveals substantially reduced population differentiation at northern latitudes.  

PubMed

Previous studies of the intertidal copepod Tigriopus californicus revealed one of the highest levels of mitochondrial DNA differentiation ever reported among conspecific populations. The present study extends the geographical sampling northward, adding populations from northern California to south-east Alaska. The mitochondrial phylogeny for the entire species range, based on cytochrome oxidase I sequences for a total of 49 individuals from 27 populations, again shows extreme differentiation among populations (up to 23%). However, populations from Oregon northwards appear to be derived and have interpopulation divergences five times lower than those between southern populations. Furthermore, although few individuals were sequenced from each locality, populations from Puget Sound northward had significantly reduced levels of within-population variation. These patterns are hypothesized to result from the contraction and expansion of populations driven by recent ice ages. PMID:11472541

Edmands, S

2001-07-01

192

Bacterial communities in the gut of the freshwater copepod Eudiaptomus gracilis.  

PubMed

Eudiaptomus gracilis is the most abundant member of the zooplankton, plays a key role in the food web of Lake Balaton (Hungary). In the present study the composition of bacterial communities of this copepod was investigated based on cultivation and molecular cloning. The cultivated bacterial strains from the gut homogenate samples of Eudiaptomus gracilis belonged to four different clades: Firmicutes, Actinobacteria, Bacteriodetes and Proteobacteria. Clone library showed high species diversity, Firmicutes, Actinobacteria, Proteobacteria, representatives of Deinococcus-Thermus lineage and Cyanobacteria were detected. The isolated strains were very effective in degradation of different biopolymers. Many of the detected bacteria are known as opportunistic human or fish pathogens (Pseudomonas spp., Aeromonas spp., Chryseobacterium sp. and Staphylococcus sp.). PMID:21780147

Homonnay, Zalán G; Kéki, Zsuzsa; Márialigeti, Károly; Tóth, Erika M

2012-02-01

193

Seasonal lipid dynamics in dominant Antarctic copepods: Energy for overwintering or reproduction?  

NASA Astrophysics Data System (ADS)

Copepodite stages V and females of four dominant Antarctic species of calanoid copepods were collected during various expeditions to the eastern Weddell Sea in mid-winter, late winter to early spring, summer and autumn. Analyses of total lipid content and sexual maturity showed some general similarities between species concerning the seasonal cycle of energy reserves and gonad maturation, but also revealed important interspecific differences in the life histories of these copepods. Calanus propinquus and Metridia gerlachei exhibited a seasonal lipid pattern with maxima in autumn and lipid minima during spring. Lipid decrease in the females usually coincided with gonad maturation, which proceeded well before the onset of phytoplankton production. This basic pattern was not as clearly discernible in the females of Calanoides acutus and Rhincalanus gigas. In the Weddell Sea, C. propinquus and C. acutus reached much higher lipid levels and seemed to rely more on internal energy depots than did M. gerlachei and R. gigas. The specific timing of reproduction in the Weddell Sea also differed among the species. M. gerlachei had the longest reproductive period, probably extending from September to March, followed by C. propinquus (October-February) and C. acutus (November-March). In contrast, R. gigas seemed to reproduce only from late December to February in the eastern Weddell Sea. Our findings emphasize the importance of lipid reserves for fueling reproductive processes before the spring phytoplankton bloom becomes available. Only a smaller portion of the accumulated energy stores appears to be utilized for metabolic maintenance during the food-limited winter period.

Hagen, Wilhelm; Schnack-Schiel, Sigrid B.

1996-02-01

194

Gonad morphology, oocyte development and spawning cycle of the calanoid copepod Acartia clausi  

NASA Astrophysics Data System (ADS)

Information on gonad morphology and its relation to basic reproductive parameters such as clutch size and spawning frequency is lacking for Acartia clausi, a dominant calanoid copepod of the North Sea. To fill this gap, females of this species were sampled at Helgoland Roads from mid March to late May 2001. Gonad structure and oogenesis were studied using a combination of histology and whole-body-analysis. In addition, clutch size and spawning frequency were determined in incubation experiments, during which individual females were monitored at short intervals for 8 and 12 h, respectively. The histological analysis revealed that the ovary of A. clausi is w-shaped with two distinct tips pointing posteriorly. It is slightly different from that of other Acartia species and of other copepod taxa. From the ovary, two anterior diverticula extend into the head region, and two posterior diverticula extend to the genital opening in the abdomen. Developing oocytes change in shape and size, and in the appearance of the nucleus and the ooplasm. Based on these morphological characteristics, different oocyte development stages (OS) were identified. Mitotically dividing oogonia and young oocytes (OS 0) were restricted to the ovary, whereas vitellogenic oocytes (OS 1 4) were present in the diverticula. The development stage of the oocytes increased with distance to the ovary in both, anterior and posterior diverticula. Most advanced oocytes were situated ventrally, and their number varied between 1 and 18, at a median of 4. All oocyte development stages co-occur indicating that oogenesis in A. clausi is a continuous process. These morphological features reflect the reproductive traits of this species. In accordance with the low numbers of mature oocytes in the gonads, females usually produced small clutches of one to five eggs. Clutches were released throughout the entire observation period at intervals of 90 min (median) resulting in mean egg production rates of 18 28 eggs female-1 day-1.

Eisfeld, Sonja M.; Niehoff, Barbara

2007-09-01

195

The nature of interactions that contribute to postzygotic reproductive isolation in hybrid copepods.  

PubMed

Deleterious interactions within the genome of hybrids can lower fitness and result in postzygotic reproductive isolation. Understanding the genetic basis of these deleterious interactions, known as Dobzhansky-Muller incompatibilities, is the subject of intense current study that seeks to elucidate the nature of these deleterious interactions. Hybrids from crosses of individuals from genetically divergent populations of the intertidal copepod Tigriopus californicus provide a useful model in which to study Dobzhansky-Muller incompatibilities. Studies of the basis of postzygotic reproductive isolation in this species have revealed a number of patterns. First, there is evidence for a breakdown in genomic coadaptation between mtDNA-encoded and nuclear-encoded proteins that can result in a reduction in hybrid fitness in some crosses. It appears from studies of the individual genes involved in these interactions that although this coadaptation could lead to asymmetries between crosses, patterns of genotypic viabilities are not often consistent with simple models of genomic coadaptation. Second, there is a large impact of environmental factors on these deleterious interactions suggesting that they are not strictly intrinsic in nature. Temperature in particular appears to play an important role in determining the nature of these interactions. Finally, deleterious interactions in these hybrid copepods appear to be complex in terms of the number of genetic factors that interact to lead to reductions in hybrid fitness. This complexity may stem from three or more factors that all interact to cause a single incompatibility or the same factor interacting with multiple other factors independently leading to multiple incompatibilities. PMID:21104425

Willett, Christopher S

2011-05-01

196

A gene-based SNP resource and linkage map for the copepod Tigriopus californicus  

PubMed Central

Background As yet, few genomic resources have been developed in crustaceans. This lack is particularly evident in Copepoda, given the extraordinary numerical abundance, and taxonomic and ecological diversity of this group. Tigriopus californicus is ideally suited to serve as a genetic model copepod and has been the subject of extensive work in environmental stress and reproductive isolation. Accordingly, we set out to develop a broadly-useful panel of genetic markers and to construct a linkage map dense enough for quantitative trait locus detection in an interval mapping framework for T. californicus--a first for copepods. Results One hundred and ninety Single Nucleotide Polymorphisms (SNPs) were used to genotype our mapping population of 250 F2 larvae. We were able to construct a linkage map with an average intermarker distance of 1.8 cM, and a maximum intermarker distance of 10.3 cM. All markers were assembled into linkage groups, and the 12 linkage groups corresponded to the 12 known chromosomes of T. californicus. We estimate a total genome size of 401.0 cM, and a total coverage of 73.7%. Seventy five percent of the mapped markers were detected in 9 additional populations of T. californicus. Of available model arthropod genomes, we were able to show more colocalized pairs of homologues between T. californicus and the honeybee Apis mellifera, than expected by chance, suggesting preserved macrosynteny between Hymenoptera and Copepoda. Conclusions Our study provides an abundance of linked markers spanning all chromosomes. Many of these markers are also found in multiple populations of T. californicus, and in two other species in the genus. The genomic resource we have developed will enable mapping throughout the geographical range of this species and in closely related species. This linkage map will facilitate genome sequencing, mapping and assembly in an ecologically and taxonomically interesting group for which genomic resources are currently under development. PMID:22103327

2011-01-01

197

Distinctive lipid composition of the copepod Limnocalanus macrurus with a high abundance of polyunsaturated fatty acids.  

PubMed

We studied the copepod Limnocalanus macrurus for seasonal variation in the composition of fatty acids, wax esters and sterols in large boreal lakes, where it occurs as a glacial-relict. Vast wax ester reserves of Limnocalanus were accumulated in a period of only two months, and comprised mono- and polyunsaturated fatty acids (PUFA) and saturated fatty alcohols. In winter, the mobilization of wax esters was selective, and the proportion of long-chain polyunsaturated wax esters declined first. PUFA accounted for >50% of all fatty acids throughout the year reaching up to ca. 65% during late summer and fall. Long-chain PUFA 20:5n-3 and 22:6n-3 together comprised 17-40% of all fatty acids. The rarely reported C24 and C26 very-long-chain PUFA (VLC-PUFA) comprised 6.2 ± 3.4 % of all fatty acids in August and 2.1 ± 1.7% in September. The VLC-PUFA are presumably synthesized by Limnocalanus from shorter chain-length precursors because they were not found in the potential food sources. We hypothesize that these VLC-PUFA help Limnocalanus to maximize lipid reserves when food is abundant. Sterol content of Limnocalanus, consisting ca. 90% of cholesterol, did not show great seasonal variation. As a lipid-rich copepod with high abundance of PUFA, Limnocalanus is excellent quality food for fish. The VLC-PUFA were also detected in planktivorous fish, suggesting that these compounds can be used as a trophic marker indicating feeding on Limnocalanus. PMID:25092258

Hiltunen, Minna; Strandberg, Ursula; Keinänen, Markku; Taipale, Sami; Kankaala, Paula

2014-09-01

198

Experimental infections of copepods and sticklebacks Gasterosteus aculeatus with small ensheathed and large third-stage larvae of Anisakis simplex (Nematoda, Ascaridoidea, Anisakidae)  

Microsoft Academic Search

Free-swimming ensheathed larvae of Anisakis simplex were shown experimentally to be ingested by the copepods Oitona similis and Acartia tonsa and by the nauplii of barnacles Balanus sp. The larvae did not grow in the copepod hemocoel. Experimental infections of various malacostracans were unsuccessful.\\u000a Sticklebacks Gasterosteus aculeatus are naturally infected with larvae of A. simplex in coastal brackish water. Such

Marianne Køie

2001-01-01

199

Mesozooplankton distribution, feeding and reproduction of Calanus finmarchicus in the western Norwegian Sea in relation to hydrography and chlorophyll a in spring  

Microsoft Academic Search

Species composition, mesozooplankton distribution, and feeding and reproduction of Calanus finmarchicus were investigated in the western Norwegian Sea in May 2003. Copepods were the most numerous group (~85-96% of all the animals caught). Calanus finmarchicus (mainly stage CV and females) was the dominant species among the copepods (~42-92%). Among the copepods Oithona similis was the second most numerous species (~5-58%).

Irina Prokopchuk

2003-01-01

200

Food intake and growth of Sarsia tubulosa (SARS, 1835), with quantitative estimates of predation on copepod populations  

NASA Astrophysics Data System (ADS)

In laboratory tests food intake by the hydromedusa Sarsia tubulosa, which feeds on copepods, was quantified. Estimates of maximum predation are presented for 10 size classes of Sarsia. Growth rates, too, were determined in the laboratory, at 12°C under ad libitum food conditions. Mean gross food conversion for all size classes averaged 12%. From the results of a frequent sampling programme, carried out in the Texelstroom (a tidal inlet of the Dutch Wadden Sea) in 1983, growth rates of Sarsia in the field equalled maximum growth under experimental conditions, which suggests that Sarsia in situ can feed at an optimum level. Two estimates of predation pressure in the field matched very closely and lead to the conclusion that the impact of Sarsia predation on copepod standing stocks in the Dutch coastal area, including the Wadden Sea, is generally negligible.

Daan, Rogier

201

Occurrence and effects of the parasitic copepod Salmincola carpionis on salmonids in the Nikko District, central Japan  

NASA Astrophysics Data System (ADS)

Salmincola carpionis (Krøyer, 1837) occurred on brook trout ( Salvelinus fontinalis) and whitespotted charr ( Salvelinus leucomaenis) reared at a fisheries research institute in the Nikko District, central Japan, and also on a wild population of the latter species that had returned for spawning from a lake to streams near the institute. Its infection levels on these salmonids were associated with age and size of fish and the location of rearing ponds, older (larger) fish reared in the lower-located ponds being more frequently and heavily infected than smaller (younger) fish from the upper-located ponds. Swellings were observed at sites where the bulla of S. carpionis was deeply implanted. The condition factor of heavily infected (>50 copepods) fish was lower than those of lightly infected fish (1-18 copepods). Salmincola carpionis did not occur on lake trout ( Salvelinus namaycush) which belong to the subgenus Cristivomer, as well as on salmonids of the genera Oncorhynchus and Salmo, possibly due strict host specificity.

Nagasawa, Kazuya; Ikuta, Kazumasa; Nakamura, Hidefumi; Shikama, Toshio; Kitamura, Shoji

1998-06-01

202

Long-term effects of elevated CO? and temperature on the Arctic calanoid copepods Calanus glacialis and C. hyperboreus.  

PubMed

The sensitivity of copepods to ocean acidification (OA) and warming may increase with time, however, studies >10 days and on synergistic effects are rare. We therefore incubated late copepodites and females of two dominant Arctic species, Calanus glacialis and Calanushyperboreus, at 0 °C at 390 and 3000 ?atm pCO? for several months in fall/winter 2010. Respiration rates, body mass and mortality in both species and life stages did not change with pCO?. To detect synergistic effects, in 2011 C. hyperboreus females were kept at different pCO? and temperatures (0, 5, 10 °C). Incubation at 10°C induced sublethal stress, which might have overruled effects of pCO?. At 5 °C and 3000 ?atm, body carbon was significantly lowest indicating a synergistic effect. The copepods, thus, can tolerate pCO? predicted for a future ocean, but in combination with increasing temperatures they could be sensitive to OA. PMID:24529340

Hildebrandt, Nicole; Niehoff, Barbara; Sartoris, Franz Josef

2014-03-15

203

Subitaneous, diapause, and delayed-hatching eggs of planktonic copepods from the northern Gulf of Mexico: morphology and hatching success  

Microsoft Academic Search

Experiments were conducted to examine the morphology and hatching success of eggs, either spawned by freshly caught planktonic\\u000a copepods or recovered from bottom sediments in the northern Gulf of Mexico. Collections were made between August 1992 and\\u000a September 1995. Eggs of nine species were described and these differed in their diameter, color and surface attributes. Three\\u000a types of eggs were

F. Chen; N. H. Marcus

1997-01-01

204

Direct sampling and in situ observation of a persistent copepod aggregation in the mesopelagic zone of the Santa Barbara Basin  

Microsoft Academic Search

Observations from a one-person submersible (“Wasp”) in fall, 1982, revealed a persistent aggregation of non-migrating, Stage V copepodites of Calanus pacificus californicus Brodsky in a band 20±3 m thick at a depth of 450 m, about 100 m above the bottom of the Santa Barbara Basin, California. Copepod abundances, calculated from nearest-neighbor distances measured directly from the submersible, yielded maximum

A. L. Alldredge; B. H. Robison; A. Fleminger; J. J. Torres; J. M. King; W. M. Hamner

1984-01-01

205

The three-dimensional prey field of the northern krill, Meganyctiphanes norvegica , and the escape responses of their copepod prey  

Microsoft Academic Search

In the north Atlantic, Meganyctiphanes norvegica feeds predominantly on copepods, including Calanus spp. To quantify its perceptual field for prey, and the sensory systems underlying prey detection, the responses of tethered\\u000a krill to free-swimming Calanus spp. were observed in 3D using silhouette video imaging. An attack–which occurred despite the krill’s being tethered—was\\u000a characterized by a pronounced movement of the krill’s

Mari B. Abrahamsen; Howard I. Browman; David M. Fields; Anne Berit Skiftesvik

2010-01-01

206

Effects of Phenanthrene and Metal-Contaminated Sediment on the Feeding Activity of the Harpacticoid Copepod, Schizopera knabeni  

Microsoft Academic Search

The effects of sediments contaminated with sublethal concentrations of phenanthrene (PAH) and metals (Cd, Hg, Pb) were evaluated\\u000a in relation to their influence on the feeding activity of a harpacticoid copepod, Schizopera knabeni. A metal mixture (at the ratio of 5Pb:3Cd:2Hg) and Cd alone reduced grazing rates of S. knabeni feeding on 14C-labeled microalgae. Cadmium alone and Cd combined with

Soraya J. Silva; Kevin R. Carman; John W. Fleeger; Tonya Marshall; Sidney J. Marlborough

2009-01-01

207

The Parasitic Dinoflagellates Blastodinium spp. Inhabiting the Gut of Marine, Planktonic Copepods: Morphology, Ecology, and Unrecognized Species Diversity  

PubMed Central

Blastodinium is a genus of dinoflagellates that live as parasites in the gut of marine, planktonic copepods in the World’s oceans and coastal waters. The taxonomy, phylogeny, and physiology of the genus have only been explored to a limited degree and, based on recent investigations, we hypothesize that the morphological and genetic diversity within this genus may be considerably larger than presently recognized. To address these issues, we obtained 18S rDNA and ITS gene sequences for Blastodinium specimens of different geographical origins, including representatives of the type species. This genetic information was in some cases complemented with new morphological, ultrastructural, physiological, and ecological data. Because most current knowledge about Blastodinium and its effects on copepod hosts stem from publications more than half a century old, we here summarize and discuss the existing knowledge in relation to the new data generated. Most Blastodinium species possess functional chloroplasts, but the parasitic stage, the trophocyte, has etioplasts and probably a limited photosynthetic activity. Sporocytes and swarmer cells have well-developed plastids and plausibly acquire part of their organic carbon needs through photosynthesis. A few species are nearly colorless with no functional chloroplasts. The photosynthetic species are almost exclusively found in warm, oligotrophic waters, indicating a life strategy that may benefit from copepods as microhabitats for acquiring nutrients in a nutrient-limited environment. As reported in the literature, monophyly of the genus is moderately supported, but the three main groups proposed by Chatton in 1920 are consistent with molecular data. However, we demonstrate an important genetic diversity within the genus and provide evidences for new groups and the presence of cryptic species. Finally, we discuss the current knowledge on the occurrence of Blastodinium spp. and their potential impact on natural copepod populations. PMID:22973263

Skovgaard, Alf; Karpov, Sergey A.; Guillou, Laure

2012-01-01

208

Temporal changes of abundance, biomass and production of copepod community in a shallow temperate estuary (Ria de Aveiro, Portugal)  

NASA Astrophysics Data System (ADS)

The present study reports on temporal changes of abundance, biomass and secondary production of the copepod community of Ria de Aveiro (Portugal). Zooplankton sampling and hydrological measurements (salinity, temperature, chlorophyll a and nutrients concentrations) were conducted at four occasions (June 2000, September 2000, December 2000 and March 2001), at 6 sampling stations and during ebb and flood. The contribution of copepods (from nauplius to adults) to the total abundance and biomass of the zooplankton community of Ria de Aveiro (Portugal) was equal to 63.6% and 62.0%, respectively (annual average). The estimate of nauplius abundance given by two zooplankton nets with different meshes was significantly different ( P < 0.001) with the 64 ?m net collecting 13.9 times more than the 125 ?m one. No significant differences were found for copepodites and adults. The abundance of all development stages (except adults) was positively correlated ( P < 0.05) with salinity and temperature. The seasonal patterns of abundance and biomass were similar to those found in other temperate coastal waters. Mean daily secondary production rate (mean ± SE) estimated by the Huntley and Lopez growth model [Huntley, M.E., Lopez, M.D.G., 1992. Temperature-dependent production of marine copepods: a global synthesis. American Naturalist 140, 201-242] was 22% higher than the value given by the application of the Hirst and Bunker model [Hirst, A.G., Bunker, A.J., 2003. Growth of marine planktonic copepods: global rates and patterns in relation to chlorophyll a, temperature, and body weight. Limnology and Oceanography 48, 1988-2010]: 3.71 ± 0.540 and 2.90 ± 0.422 mg C m -3 d -1, respectively.

Leandro, Sérgio Miguel; Morgado, Fernando; Pereira, Fábio; Queiroga, Henrique

2007-08-01

209

Mesozooplankton and copepod community structures in the southern East China Sea: the status during the monsoonal transition period in September  

NASA Astrophysics Data System (ADS)

A field sampling was conducted before the onset of the northeasterly monsoon to investigate the copepod community composition during the monsoon transition period at the northern coast of Taiwan (East China Sea). In total, 22 major mesozooplankton taxa were found, with the Calanoida (relative abundance: 66.36%) and Chaetognatha (9.44%) being the most abundant. Mesozooplankton densities ranged between 226.91 and 2162.84 individuals m-3 (mean ± SD: 744.01 ± 631.5 individuals m-3). A total of 49 copepod species were identified, belonging to 4 orders, 19 families, and 30 genera. The most abundant species were: Temora turbinata (23.50%), Undinula vulgaris (17.92%), and Acrocalanus gibber (14.73%). The chaetognath Flaccisagitta enflata occurred at all 8 sampling stations, providing a 95% portion of the overall chaetognath contribution. Amphipoda were abundant at stations 4 and 5, with Hyperioides sibaginis and Lestigonus bengalensis being dominant, and comprising about 50% of all amphipods. Chaetognath abundance showed a significantly negative correlation with salinity ( r = 0.77, p = 0.027), whereas mesozooplankton group numbers had a significantly positive correlation with salinity ( r = 0.71, p = 0.048). Densities of four copepod species ( Calanus sinicus, Calocalanus pavo, Calanopia elliptica and Labidocera acuta) showed a significantly negative correlation with seawater temperature. Communities of mesozooplankton and copepods of northern Taiwan varied spatially with the distance to land. The results of this study provide evidence for the presence of C. sinicus in the coastal area of northern Taiwan during the early northeast monsoon transition period in September.

Tseng, Li-Chun; Dahms, Hans-Uwe; Chen, Qing-Chao; Hwang, Jiang-Shiou

2012-12-01

210

The Parasitic Dinoflagellates Blastodinium spp. Inhabiting the Gut of Marine, Planktonic Copepods: Morphology, Ecology, and Unrecognized Species Diversity.  

PubMed

Blastodinium is a genus of dinoflagellates that live as parasites in the gut of marine, planktonic copepods in the World's oceans and coastal waters. The taxonomy, phylogeny, and physiology of the genus have only been explored to a limited degree and, based on recent investigations, we hypothesize that the morphological and genetic diversity within this genus may be considerably larger than presently recognized. To address these issues, we obtained 18S rDNA and ITS gene sequences for Blastodinium specimens of different geographical origins, including representatives of the type species. This genetic information was in some cases complemented with new morphological, ultrastructural, physiological, and ecological data. Because most current knowledge about Blastodinium and its effects on copepod hosts stem from publications more than half a century old, we here summarize and discuss the existing knowledge in relation to the new data generated. Most Blastodinium species possess functional chloroplasts, but the parasitic stage, the trophocyte, has etioplasts and probably a limited photosynthetic activity. Sporocytes and swarmer cells have well-developed plastids and plausibly acquire part of their organic carbon needs through photosynthesis. A few species are nearly colorless with no functional chloroplasts. The photosynthetic species are almost exclusively found in warm, oligotrophic waters, indicating a life strategy that may benefit from copepods as microhabitats for acquiring nutrients in a nutrient-limited environment. As reported in the literature, monophyly of the genus is moderately supported, but the three main groups proposed by Chatton in 1920 are consistent with molecular data. However, we demonstrate an important genetic diversity within the genus and provide evidences for new groups and the presence of cryptic species. Finally, we discuss the current knowledge on the occurrence of Blastodinium spp. and their potential impact on natural copepod populations. PMID:22973263

Skovgaard, Alf; Karpov, Sergey A; Guillou, Laure

2012-01-01

211

The minute brain of the copepod Tigriopus californicus supports a complex ancestral ground pattern of the tetraconate cerebral nervous systems.  

PubMed

Copepods are a diverse and ecologically crucial group of minute crustaceans that are relatively neglected in terms of studies on nervous system organization. Recently, morphological neural characters have helped clarify evolutionary relationships within Arthropoda, particularly among Tetraconata (i.e., crustaceans and hexapods), and indicate that copepods occupy an important phylogenetic position relating to both Malacostraca and Hexapoda. This taxon therefore provides the opportunity to evaluate those neural characters common to these two clades likely to be results of shared ancestry (homology) versus convergence (homoplasy). Here we present an anatomical characterization of the brain and central nervous system of the well-studied harpacticoid copepod species Tigriopus californicus. We show that this species is endowed with a complex brain possessing a central complex comprising a protocerebral bridge and central body. Deutocerebral glomeruli are supplied by the antennular nerves, and a lateral protocerebral olfactory neuropil corresponds to the malacostracan hemiellipsoid body. Glomeruli contain synaptic specializations comparable to the presynaptic "T-bars" typical of dipterous insects, including Drosophila melanogaster. Serotonin-like immunoreactivity pervades the brain and ventral nervous system, with distinctive deutocerebral distributions. The present observations suggest that a suite of morphological characters typifying the Tigriopus brain reflect a ground pattern organization of an ancestral Tetraconata, which possessed an elaborate and structurally differentiated nervous system. PMID:22431149

Andrew, David R; Brown, Sheena M; Strausfeld, Nicholas J

2012-10-15

212

Role of crustacean hyperglycemic hormone (CHH) in the environmental stressor-exposed intertidal copepod Tigriopus japonicus.  

PubMed

To identify and characterize CHH (TJ-CHH) gene in the copepod Tigriopus japonicus, we analyzed the full-length cDNA sequence, genomic structure, and promoter region. The full-length TJ-CHH cDNA was 716 bp in length, encoding 136 amino acid residues. The deduced amino acid sequences of TJ-CHH showed a high similarity of the CHH mature domain to other crustaceans. Six conserved cysteine residues and five conserved structural motifs in the CHH mature peptide domain were also observed. The genomic structure of the TJ-CHH gene contained three exons and two introns in its open reading frame (ORF), and several transcriptional elements were detected in the promoter region of the TJ-CHH gene. To investigate transcriptional change of TJ-CHH under environmental stress, T. japonicus were exposed to heat treatment, UV-B radiation, heavy metals, and water-accommodated fractions (WAFs) of Iranian crude oil. Upon heat stress, TJ-CHH transcripts were elevated at 30 °C and 35 °C for 96 h in a time-course experiment. UV-B radiation led to a decreased pattern of the TJ-CHH transcript 48 h and more after radiation (12 kJ/m(2)). After exposure of a fixed dose (12 kJ/m(2)) in a time-course experiment, TJ-CHH transcript was down-regulated in time-dependent manner with a lowest value at 12h. However, the TJ-CHH transcript level was increased in response to five heavy metal exposures for 96 h. Also, the level of the TJ-CHH transcript was significantly up-regulated at 20% of WAFs after exposure to WAFs for 48 h and then remarkably reduced in a dose-dependent manner. These findings suggest that the enhanced TJ-CHH transcript level is associated with a cellular stress response of the TJ-CHH gene as shown in decapod crustaceans. This study is also helpful for a better understanding of the detrimental effects of environmental changes on the CHH-triggered copepod metabolism. PMID:23797038

Kim, Bo-Mi; Jeong, Chang-Bum; Han, Jeonghoon; Kim, Il-Chan; Rhee, Jae-Sung; Lee, Jae-Seong

2013-09-01

213

[New and recognized species of copepods (Chitonophilidae)--parasites of chitons of Northern Pacific].  

PubMed

Descriptions and figures of the following new and recognized species of copepods parasitizing chitons are given: Leptochitonicola sphaerica sp. n. from Leptochiton rugatus (Carpenter in Pilsbry, 1892) from the Sea of Japan, Leptochitonicola intermedia sp. n. from Leptochiton sp. from off Eastern Kamchatka, L. hanleyellai sp. n. from Hanleyella asiatica Sirenko, 1973 from near Commanders Islands, Leptochitonicola attenuata sp. n. from Leptochiton cf. rugatus from near the Bering Sea coast of Bering Island, Ischnochitonika kurochkini sp. n. on Lepidozona multigranosa Sirenko, 1975, L. kobjakovae kobjakovae (Jakovleva, 1952) and L. albrechti (Schrenck, 1863) all from the Sea of Japan and Okhotsk Sea, Ischnochitonica aleutica sp. n. on Leptochiton cf. belknapi from near the Aleutian Islands and from Kronotsky Bay, and Leptochitonoides vitiasi gen. et sp. n. from Leptochiton cf. belknapi from near Prince Wales Island. Ischnochitonica lasalliana Franz et Bullock, 1990 and I. japonica Nagasawa et al., 1991 are redescribed, new hosts and localities are given. New data on other chitonophilids are reported including recognized species. The amended diagnoses of the genera Ischnochitonika Franz et Bullock, 1990 and Leptochitonicola Avdeev et Sirenko, 1991 are provided. PMID:16396392

Avdeev, G V; Sirenko, B I

2005-01-01

214

Large, motile epifauna interact strongly with harpacticoid copepods and polychaetes at a bathyal site  

NASA Astrophysics Data System (ADS)

Strengths of interactions among groups of animals in deep-sea-sediment communities are poorly known. Large, motile epifauna (LME) such as sea cucumbers, star fishes, and demersal fishes occur in the deep sea and are sources of predation, disturbance, and habitat alteration and thus have the potential to interact strongly with infauna. At a site off the southwestern coast of the United States (32°57.3'N, 117°32.2'W, 780 m depth), we excluded the LME from five 75- ×75-cm plots with cages. After 143 d, we sampled these plots and five plots of the same size paired with them as controls. Abundances of harpacticoid copepods and polychaetes were significantly lower in cages than in controls. In several cages, nematodes and kinorhynchs were also dramatically less abundant than in paired controls. Results suggest that LME ordinarily affect the infaunal assemblage in such a way that harpacticoids and polychaetes (and perhaps nematodes and kinorhynchs) can maintain higher abundances than they can in the absence of LME, indicating that strong interactions can influence the organization of deep-sea-sediment communities. In a multivariate analysis of environmental parameters, cage and control samples were intermixed, so if the effect is transmitted by alterations of the environment by the LME, the nature of the alterations must be relatively local and remains to be discovered.

Thistle, David; Eckman, James E.; Paterson, Gordon L. J.

2008-03-01

215

Vertical distribution and abundance of natant harpacticoid copepods on a vegetated tidal flat  

NASA Astrophysics Data System (ADS)

The vertical distribution in the water column of an assemblage of species of harpacticoid copepods was studied on a vegetated tidal flat in the Fraser River estuary, British Columbia. Natant harpacticoids were collected at discrete levels with a sled-sampler made of 5 cylindrical filtering baskets centered respectively at 56, 156, 256, 356 and 456 mm above the sediment surface. Samples were collected bi-weekly from February 11 to May 27 in 1986. The vertical distribution of Zaus aurelli in the water column was roughly pyramidal with a maximum abundance at intermediate sampling levels (156-256 mm). The vertical distribution of Harpacticus uniremis was variable: maximum abundance was observed at the lowest or intermediate (156-256 mm) sampling levels. The vertical distribution of Tisbe spp. had exponential characteristics with maximum abundance at the lowest sampling level. The abundance of natant harpacticoids in the water column was computed by integrating their vertical distribution curves. The maximum abundance of Tisbe spp., Zaus aurelii, and Harpacticus uniremis was respectively 10.6, 1.96 and 0.46 individuals per cm 2 of bottom area. Recognition of specific localized patterns in the vertical distribution of natant harpacticoids and knowledge of their total abundance could ease investigations of their recognized role in the diet of the juveniles of several fish species.

D'Amours, D.

216

To eat and not be eaten: optimal foraging behaviour in suspension feeding copepods.  

PubMed

Zooplankton feed on microscopic prey that they either entrain in a feeding current or encounter as they cruise through the water. They generate fluid disturbances as they feed and move, thus elevating their risk of being detected and encountered by predators. Different feeding modes generate different hydrodynamic signals to predators and different predator encounter speeds but may also differ in their efficiency; the optimal behaviour is that which maximizes the net energy gain over the predation risk. Here, we show by means of flow visualization and simple hydrodynamic and optimization models that copepods with a diversity of feeding behaviours converge on optimal, size-independent specific clearance rates that are consistent with observed clearance rates of zooplankton, irrespective of feeding mode, species and size. We also predict magnitudes and size-scaling of swimming speeds that are consistent with observations. The rationalization of the magnitude and scaling of the clearance rates of zooplankton makes it more suitable for development of models of marine ecosystems, and is particularly relevant in predicting the size structure and biomass of pelagic communities. PMID:23075546

Kiørboe, Thomas; Jiang, Houshuo

2012-10-17

217

Maladapted gene complexes within populations of the intertidal copepod Tigriopus californicus?  

PubMed

The prevalence of F2 hybrid breakdown in interpopulation crosses of the marine copepod Tigriopus californicus can be explained by disruption of coadapted gene complexes. This study further dissects the nature of hybrid gene interactions, revealing that parental populations may also harbor maladapted gene complexes. Diagnostic molecular markers (14) were assayed in reciprocal F2 hybrids to test for gene interactions affecting viability. Results showed some evidence of nuclear-nuclear coadaptation. Although there were no significant examples of pairwise linkage disequilibrium between physically unlinked loci, one of the two reciprocal crosses did show an overall excess of parental double homozygotes and an overall dearth of nonparental double homozygotes. In contrast, the nuclear-cytoplasmic data showed a stronger tendency toward maladaptation within the specific inbred lines used in this study. For three out of four loci with significant frequency differences between reciprocal F2, homozygotes were favored on the wrong cytoplasmic background. A separate study of reciprocal backcross hybrids between the same two populations (but different inbred lines) revealed faster development time when the full haploid nuclear genome did not match the cytoplasm. The occurrence of such suboptimal gene complexes may be attributable to effects of genetic drift in small, isolated populations. PMID:19453379

Edmands, Suzanne; Northrup, Sara L; Hwang, Annmarie S

2009-08-01

218

No evidence for faster male hybrid sterility in population crosses of an intertidal copepod (Tigriopus californicus).  

PubMed

Two different forces are thought to contribute to the rapid accumulation of hybrid male sterility that has been observed in many inter-specific crosses, namely the faster male and the dominance theories. For male heterogametic taxa, both faster male and dominance would work in the same direction to cause the rapid evolution of male sterility; however, for taxa lacking differentiated sex chromosomes only the faster male theory would explain the rapid evolution of male hybrid sterility. It is currently unknown what causes the faster evolution of male sterility, but increased sexual selection on males and the sensitivity of genes involved in male reproduction are two hypotheses that could explain the observation. Here, patterns of hybrid sterility in crosses of genetically divergent copepod populations are examined to test potential mechanisms of faster male evolution. The study species, Tigriopus californicus, lacks differentiated, hemizygous sex chromosomes and appears to have low levels of divergence caused by sexual selection acting upon males. Hybrid sterility does not accumulate more rapidly in males than females in these crosses suggesting that in this taxon male reproductive genes are not inherently more prone to disruption in hybrids. PMID:17701279

Willett, Christopher S

2008-06-01

219

Molecular and quantitative trait variation within and among populations of the intertidal copepod Tigriopus californicus.  

PubMed

While molecular and quantitative trait variation may be theoretically correlated, empirical studies using both approaches frequently reveal discordant patterns, and these discrepancies can contribute to our understanding of evolutionary processes. Here, we assessed genetic variation in six populations of the copepod Tigriopus californicus. Molecular variation was estimated using five polymorphic microsatellite loci, and quantitative variation was measured using 22-life history and morphometric characters. Within populations, no correlation was found between the levels of molecular variation (heterozygosity) and quantitative variation (heritability). Between populations, quantitative subdivision (Q(ST)) was correlated with molecular subdivision when measured as F(ST) but not when measured as R(ST). Unlike most taxa studied to date, the overall level of molecular subdivision exceeded the level of quantitative subdivision (F(ST) = 0.80, R(ST) = 0.89, Q(ST) = 0.30). Factors that could contribute to this pattern include stabilizing or fluctuating selection on quantitative traits or accelerated rates of molecular evolution. PMID:14628915

Edmands, Suzanne; Harrison, J Scott

2003-10-01

220

Elevated oxidative damage is correlated with reduced fitness in interpopulation hybrids of a marine copepod.  

PubMed

Aerobic energy production occurs via the oxidative phosphorylation pathway (OXPHOS), which is critically dependent on interactions between the 13 mitochondrial DNA (mtDNA)-encoded and approximately 70 nuclear-encoded protein subunits. Disruptive mutations in any component of OXPHOS can result in impaired ATP production and exacerbated oxidative stress; in mammalian systems, such mutations are associated with ageing as well as numerous diseases. Recent studies have suggested that oxidative stress plays a role in fitness trade-offs in life-history evolution and functional ecology. Here, we show that outcrossing between populations with divergent mtDNA can exacerbate cellular oxidative stress in hybrid offspring. In the copepod Tigriopus californicus, we found that hybrids that showed evidence of fitness breakdown (low fecundity) also exhibited elevated levels of oxidative damage to DNA, whereas those with no clear breakdown did not show significantly elevated damage. The extent of oxidative stress in hybrids appears to be dependent on the degree of genetic divergence between their respective parental populations, but this pattern requires further testing using multiple crosses at different levels of divergence. Given previous evidence in T. californicus that hybridization disrupts nuclear/mitochondrial interactions and reduces hybrid fitness, our results suggest that such negative intergenomic epistasis may also increase the production of damaging cellular oxidants; consequently, mtDNA evolution may play a significant role in generating postzygotic isolating barriers among diverging populations. PMID:23902912

Barreto, Felipe S; Burton, Ronald S

2013-09-22

221

Fitness and morphological outcomes of many generations of hybridization in the copepod Tigriopus californicus.  

PubMed

Hybridization between genetically divergent populations is an important evolutionary process, with an outcome that is difficult to predict. We used controlled crosses and freely mating hybrid swarms, followed for up to 30 generations, to examine the morphological and fitness consequences of interpopulation hybridization in the copepod Tigriopus californicus. Patterns of fitness in two generations of controlled crosses were partly predictive of long-term trajectories in hybrid swarms. For one pair of populations, controlled crosses revealed neutral or beneficial effects of hybridization after the F1 generation, and hybrid swarm fitness almost always equalled or exceeded that of the midparent. For a second pair, controlled crosses showed F2 hybrid breakdown, but increased fitness in backcrosses, and hybrid swarm fitness deviated both above and below that of the parentals. Nevertheless, individual swarm replicates exhibited different fitness trajectories over time that were not related in a simple manner to their hybrid genetic composition, and fixation of fitter hybrid phenotypes was not observed. Hybridization did not increase overall morphological variation, and underlying genetic changes may have been masked by phenotypic plasticity. Nevertheless, one type of hybrid swarm exhibited a repeatable pattern of transgressively large eggsacs, indicating a positive effect of hybridization on individual fecundity. Additionally, both parental and hybrid swarms exhibited common phenotypic trends over time, indicating common selective pressures in the laboratory environment. Our results suggest that, in a system where much work has focused on F2 hybrid breakdown, the long-term fitness consequences of interpopulation hybridization are surprisingly benign. PMID:23278939

Pritchard, V L; Knutson, V L; Lee, M; Zieba, J; Edmands, S

2013-02-01

222

Genetic consequences of many generations of hybridization between divergent copepod populations.  

PubMed

Crosses between populations of the copepod Tigriopus californicus typically result in outbreeding depression. In this study, replicate hybrid populations were initiated with first generation backcross hybrids between two genetically distinct populations from California: Royal Palms (RP) and San Diego (SD). Reciprocal F(1) were backcrossed to SD, resulting in expected starting frequencies of 25% RP/75% SD nuclear genes on either a pure RP cytoplasmic or a pure SD cytoplasmic background. After 1 year of hybridization (up to 15 generations), seven microsatellite loci were scored in two replicates on each cytoplasmic background. Frequencies of the rarer RP alleles increased significantly in all four replicates, regardless of cytoplasmic source, producing a mean hybridity of 0.97 (maximum = 1), instead of the expected 0.50. Explicit tests for heterozygote excess across loci and replicates showed significant deviations. Only the two physically linked markers showed linkage disequilibrium in all replicates. Subsequent fitness assays in parental populations and early generation hybrids revealed lower fitness in RP than SD, and significant F(2) breakdown. Computer simulations showed that selection must be invoked to explain the shift in allele frequencies. Together, these results suggest that hybrid inferiority in early generations gave way to hybrid superiority in later generations. PMID:15618307

Edmands, S; Feaman, H V; Harrison, J S; Timmerman, C C

2005-01-01

223

Trade-offs, geography, and limits to thermal adaptation in a tide pool copepod.  

PubMed

Antagonistic correlations among traits may slow the rate of adaptation to a changing environment. The tide pool copepod Tigriopus californicus is locally adapted to temperature, but within populations, the response to selection for increased heat tolerance plateaus rapidly, suggesting either limited variation within populations or costs of increased tolerance. To measure possible costs of thermal tolerance, we selected for increased upper lethal limits for 10 generations in 22 lines of T. californicus from six populations. Then, for each line, we measured six fitness-related traits. Selected lines showed an overall increase in male and female body sizes, fecundity, and starvation resistance, suggesting a small benefit from (rather than costs of) increased tolerance. The effect of selection on correlated traits also varied significantly by population for five traits, indicating that the genetic basis for the selection response differed among populations. Our results suggest that adaptation was limited by the presence of variation within isolated populations rather than by costs of increased tolerance. PMID:23669546

Kelly, Morgan W; Grosberg, Richard K; Sanford, Eric

2013-06-01

224

Elevated oxidative damage is correlated with reduced fitness in interpopulation hybrids of a marine copepod  

PubMed Central

Aerobic energy production occurs via the oxidative phosphorylation pathway (OXPHOS), which is critically dependent on interactions between the 13 mitochondrial DNA (mtDNA)-encoded and approximately 70 nuclear-encoded protein subunits. Disruptive mutations in any component of OXPHOS can result in impaired ATP production and exacerbated oxidative stress; in mammalian systems, such mutations are associated with ageing as well as numerous diseases. Recent studies have suggested that oxidative stress plays a role in fitness trade-offs in life-history evolution and functional ecology. Here, we show that outcrossing between populations with divergent mtDNA can exacerbate cellular oxidative stress in hybrid offspring. In the copepod Tigriopus californicus, we found that hybrids that showed evidence of fitness breakdown (low fecundity) also exhibited elevated levels of oxidative damage to DNA, whereas those with no clear breakdown did not show significantly elevated damage. The extent of oxidative stress in hybrids appears to be dependent on the degree of genetic divergence between their respective parental populations, but this pattern requires further testing using multiple crosses at different levels of divergence. Given previous evidence in T. californicus that hybridization disrupts nuclear/mitochondrial interactions and reduces hybrid fitness, our results suggest that such negative intergenomic epistasis may also increase the production of damaging cellular oxidants; consequently, mtDNA evolution may play a significant role in generating postzygotic isolating barriers among diverging populations. PMID:23902912

Barreto, Felipe S.; Burton, Ronald S.

2013-01-01

225

Functional coadaptation between cytochrome c and cytochrome c oxidase within allopatric populations of a marine copepod.  

PubMed

Geographically isolated populations may accumulate alleles that function well on their own genetic backgrounds but poorly on the genetic backgrounds of other populations. Consequently, interpopulation hybridization may produce offspring of low fitness as a result of incompatibilities arising in allopatry. Genes participating in these epistatic incompatibility systems remain largely unknown. In fact, despite the widely recognized importance of epistatic interactions among gene products, few data directly address the functional consequences of such interactions among natural genetic variants. In the marine copepod, Tigriopus californicus, we found that the cytochrome c variants isolated from two different populations each had significantly higher activity with the cytochrome c oxidase derived from their respective source population. Three amino acid substitutions in the cytochrome c protein appear to be sufficient to confer population specificity. These results suggest that electron transport system (ETS) proteins form coadapted sets of alleles within populations and that disruption of the coadapted ETS gene complex leads to functional incompatibilities that may lower hybrid fitness. PMID:12271133

Rawson, Paul D; Burton, Ronald S

2002-10-01

226

Isolation and characterization of cytochrome c from the marine copepod Tigriopus californicus.  

PubMed

Mitochondrial energy production requires complex interactions among proteins encoded in both the nuclear and mitochondrial genomes. The intergenomic coevolution of interacting gene products has been previously suggested based on interspecific comparisons of cytochrome c (encoded by the nuclear CYC gene) and cytochrome c oxidase (partly encoded in the mitochondrial DNA by the COX1, COX2 and COX3 genes). In the intertidal copepod, Tigriopus californicus, non-synonymous substitutions in the COX1 gene have previously been found in interpopulation comparisons. In order to determine if CYC also shows interpopulation variation, this gene was isolated from a cDNA library using a degenerate primer/polymerase chain reaction approach. Characterization of a cDNA sequence and 25 genomic DNA sequences derived from four T. californicus populations yielded the following results: (1) the T. californicus CYC gene is interrupted by an intron that occurs at the same position as the intron found in vertebrate CYC genes; (2) there is extensive sequence variation within both the coding region and intron of this gene and the vast majority of this variation occurs between sequences drawn from geographically distinct populations; (3) the coding sequence variation includes a minimum of five amino acid replacement substitutions; (4) segregation of length variants among offspring in an interpopulation cross revealed genotypic ratios consistent with the proposed allelic nature of the CYC variants. These results demonstrate that the requisite genetic variation required for intergenomic coevolution exists in the CYC-COX system in T. californicus. PMID:10806346

Rawson, P D; Brazeau, D A; Burton, R S

2000-05-01

227

Occurrence of parasitic copepods in Carangid fishes from Parangipettai, Southeast coast of India.  

PubMed

In the present study, 68 fishes were infested out of 544 specimens examined from six different species of Carangid fishes which were collected from Parangipettai coastal waters. Eight species of parasitic copepods were found on gill filaments, body surface and nasal capsule regions. The maximum prevalence was recorded in Carangoides malabaricus (22.5 %) and minimum was noticed in (2.4 %) Selaroides leptolepis. The intensity of infection ranged from 1 to 1.2. Thus, considerable variation in the respiratory area was observed owing to the attachment of parasites in the infected fishes. Caligus sp. and C. epidemicus parasites were attached to body surface and only one Sphyriid sp. parasites were found in nasal capsule region. It is very difficult to estimate the actual harm to fish caused by the presence of parasites; if this is uneasy in cultured fish, it is almost impossible in feral fish populations. It should also be emphasized that the presence of a parasite does not necessarily imply manifestation of a disease. In aquaculture, some parasites are able to reproduce rapidly and heavily infect a large proportion of fish which may lead to diseases with significant economic consequences. PMID:25035593

Rameshkumar, Ganapathy; Ravichandran, Samuthirapandian; Venmathi Maran, B A

2014-09-01

228

Interannual variations in vital rates of copepods and euphausiids during the RISE study 2004-2006  

NASA Astrophysics Data System (ADS)

The River Influences on Shelf Ecosystems (RISE) program investigated the role of the Columbia River plume in enhancing productivity in the upwelling zone off Washington during four cruises from 2004 to 2006. Measurements of growth rates and brood sizes of euphausiids and egg production rates of copepods were used as indices of secondary production to determine whether these rates differed (1) among cruises as a function of differences in upwelling strength and (2) with latitude, both within the RISE study area and between the coastal waters of Washington and Oregon. Euphausia pacifica growth rates were significantly higher during June 2006 than during July 2004 and June 2005 but not significantly different between the RISE study area and Newport Hydrographic (NH) Line, Oregon. Euphausiid brood sizes were significantly higher during August 2005 than during any other cruise for both E. pacifica and Thysanoessa spinifera; our experiments did not indicate that brood sizes were higher in the northern part of the RISE study region. E. pacifica broods were larger for NH than RISE, but T. spinifera broods were not. Significant differences in egg production rates (EPRs) were found among cruises for both Calanus pacificus and C. marshallae, with higher EPRs during August 2005. EPRs on other cruises were less than half the maximum rates known for these species. EPRs of C. marshallae were similar between RISE and NH; C. pacificus EPRs were significantly higher (lower) in the RISE region in 2005 (2006). Interannual differences in ocean conditions affected zooplankton production more strongly than differences in latitude.

Shaw, C. Tracy; Feinberg, Leah R.; Peterson, William T.

2009-02-01

229

Partitioning of respiratory energy and environmental tolerance in the copepods Calanipeda aquaedulcis and Arctodiaptomus salinus  

NASA Astrophysics Data System (ADS)

Total and basal metabolism was studied in the widely distributed copepod species Calanipeda aquaedulcis and Arctodiaptomus salinus of both genders in order to estimate respiratory energy partitioning. Specific oxygen consumption was found to double in C. aquaedulcis than in A. salinus, and double in males than in females both in terms of total and basal metabolism. Respiration rates in females carrying ovisacs were 1.49 and 1.43 times higher than those in females without ovisacs for C. aquaedulcis and A. salinus, respectively. Extra energy expenditures are due to carrying ovisacs and egg respiration. There was no significant effect of salinity (0.1-40), oxygen concentration (1-8 mg O2 l-1) or crowding on oxygen consumption confirming the hypothesis that C. aquaedulcis and A. salinus are the animals with a type of respiratory metabolism independent of salinity and oxygen concentration. At critical oxygen concentrations less than 1 mg O2 l-1 respiration rate fell notably by approximately an order of magnitude in both species and in both genders.

Svetlichny, Leonid; Khanaychenko, Antonina; Hubareva, Elena; Aganesova, Larisa

2012-12-01

230

Climate, copepods and seabirds in the boreal Northeast Atlantic - current state and future outlook.  

PubMed

The boreal Northeast Atlantic is strongly affected by current climate change, and large shifts in abundance and distribution of many organisms have been observed, including the dominant copepod Calanus finmarchicus, which supports the grazing food web and thus many fish populations. At the same time, large-scale declines have been observed in many piscivorous seabirds, which depend on abundant small pelagic fish. Here, we combine predictions from a niche model of C. finmarchicus with long-term data on seabird breeding success to link trophic levels. The niche model shows that environmental suitability for C. finmarchicus has declined in southern areas with large breeding seabird populations (e.g. the North Sea), and predicts that this decline is likely to spread northwards during the 21st century to affect populations in Iceland and the Faroes. In a North Sea colony, breeding success of three common piscivorous seabird species [black-legged kittiwake (Rissa tridactyla), common guillemot (Uria aalge) and Atlantic puffin (Fratercula arctica)] was strongly positively correlated with local environmental suitability for C. finmarchicus, whereas this was not the case at a more northerly colony in west Norway. Large seabird populations seem only to occur where C. finmarchicus is abundant, and northward distributional shifts of common boreal seabirds are therefore expected over the coming decades. Whether or not population size can be maintained depends on the dispersal ability and inclination of these colonial breeders, and on the carrying capacity of more northerly areas in a warmer climate. PMID:23504776

Frederiksen, Morten; Anker-Nilssen, Tycho; Beaugrand, Grégory; Wanless, Sarah

2013-02-01

231

Predation by the Dwarf Seahorse on Copepods: Quantifying Motion and Flows Using 3D High Speed Digital Holographic Cinematography - When Seahorses Attack!  

NASA Astrophysics Data System (ADS)

Copepods are an important planktonic food source for most of the world's fish species. This high predation pressure has led copepods to evolve an extremely effective escape response, with reaction times to hydrodynamic disturbances of less than 4 ms and escape speeds of over 500 body lengths per second. Using 3D high speed digital holographic cinematography (up to 2000 frames per second) we elucidate the role of entrainment flow fields generated by a natural visual predator, the dwarf seahorse (Hippocampus zosterae) during attacks on its prey, Acartia tonsa. Using phytoplankton as a tracer, we recorded and reconstructed 3D flow fields around the head of the seahorse and its prey during both successful and unsuccessful attacks to better understand how some attacks lead to capture with little or no detection from the copepod while others result in failed attacks. Attacks start with a slow approach to minimize the hydro-mechanical disturbance which is used by copepods to detect the approach of a potential predator. Successful attacks result in the seahorse using its pipette-like mouth to create suction faster than the copepod's response latency. As these characteristic scales of entrainment increase, a successful escape becomes more likely.

Gemmell, Brad; Sheng, Jian; Buskey, Ed

2008-11-01

232

Copepod community growth rates in relation to body size, temperature, and food availability in the East China Sea: a test of metabolic theory of ecology  

NASA Astrophysics Data System (ADS)

Zooplankton play an essential role in marine food webs and understanding how community-level growth rates of zooplankton vary in the field is critical for predicting how marine ecosystem function may vary in the face of environmental changes. Here, we used the artificial cohort method to examine the effects of temperature, body size, and chlorophyll concentration (a proxy for food) on weight-specific growth rates for copepod communities in the East China Sea. Specifically, we tested the hypothesis that copepod community growth rates can be described by the metabolic theory of ecology (MTE), linking spatio-temporal variation of copepod growth rate with temperature and their body size. Our results generally agree with predictions made by the MTE and demonstrate that weight-specific growth rates of copepod communities in our study area are positively related with temperature and negatively related to body size. However, the regression coefficients of body size do not approach the theoretical predictions. Furthermore, we find that the deviation from the MTE predictions may be partly attributed to the effect of food availability (which is not explicitly accounted for by the MTE). In addition, significant difference in the coefficients of temperature and body size exists among taxonomic groups. Our results suggest that considering the effects of food limitation and taxonomy is necessary to better understand copepod growth rates under in situ conditions, and such effects on the MTE-based prediction needs further investigation.

Lin, K. Y.; Sastri, A.; Gong, G. C.; Hsieh, C. H.

2012-11-01

233

Copepod community growth rates in relation to body size, temperature, and food availability in the East China Sea: a test of metabolic theory of ecology  

NASA Astrophysics Data System (ADS)

Zooplankton play an essential role in marine food webs, and understanding how community-level growth rates of zooplankton vary in the field is critical for predicting how marine ecosystem function may vary in the face of environmental changes. Here, we used the artificial cohort method to examine the effects of temperature, body size, and chlorophyll concentration (a proxy for food) on weight-specific growth rates for copepod communities in the East China Sea. Specifically, we tested the hypothesis that copepod community growth rates can be described by the metabolic theory of ecology (MTE), linking spatio-temporal variation of copepod growth rate with temperature and their body size. Our results generally agree with predictions made by the MTE and demonstrate that weight-specific growth rates of copepod communities in our study area are positively related with temperature and negatively related to body size. However, the regression coefficients of body size do not approach the theoretical predictions. Furthermore, we find that the deviation from the MTE predictions may be partly attributed to the effect of food availability (which is not explicitly accounted for by the MTE). In addition, significant difference in the coefficients of temperature and body size exists among taxonomic groups. Our results suggest that considering the effects of food limitation and taxonomy is necessary to better understand copepod growth rates under in situ conditions, and such effects on the MTE-based predictions need further investigation.

Lin, K. Y.; Sastri, A. R.; Gong, G. C.; Hsieh, C. H.

2013-03-01

234

Use of RNA:DNA ratios to evaluate the condition and growth of the copepod Calanus sinicus in the Southern Yellow Sea  

NASA Astrophysics Data System (ADS)

Calanus sinicus, a dominant calanoid copepod in the Yellow Sea, is an important link in the food web between phytoplankton and higher trophic levels. Its populations typically start to develop in later winter with a maximum of individuals in early summer. To study the correlation between changes in the abundance of this species and changes in food resources and the physical environment, RNA and DNA concentrations and egg production rates (EPR) were measured, and RNA:DNA ratios were calculated as indices of growth and nutritional conditions of copepods collected in the Yellow Sea from February to July. We observed pronounced seasonal and spatial variations of RNA concentrations and resulting RNA:DNA ratios. There was a positive correlation between the EPR and RNA:DNA ratios. The copepods collected in March and April, when phytoplankton were more abundant, had high RNA:DNA ratios, and contained more RNA than copepods collected during the other months. There was no significant correlation between the growth indices (RNA:DNA ratios and EPR) and chlorophyll-a concentrations (Chl a) or temperature at large temporal and spatial scales. We tracked the development of two phytoplankton blooms in April, which were dominated in turn by diatoms and dinoflagellates. We observed high concentrations of RNA and a high RNA:DNA ratio at both bloom sites during the respective blooms. During the diatom bloom, the RNA:DNA ratios in copepods increased at the onset of the bloom and decreased thereafter. In addition, we observed a positive correlation (P<0.001) between RNA-based indices and Chl a. Our results suggest that food availability plays a more important role than temperature in controlling the growth of C. sinicus in the field. Thus, the spring phytoplankton blooms in the Yellow Sea are important regulators of copepod abundance.

Ning, Juan; Li, Chaolun; Yang, Guang; Wan, Aiyong; Sun, Song

2013-12-01

235

Effects of calanoid copepod Schmackeria poplesia as a live food on the growth, survival and fatty acid composition of larvae and juveniles of Japanese flounder, Paralichthys olivaceus  

NASA Astrophysics Data System (ADS)

Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that copepods can meet the nutritional requirements of fish larvae. In this study, calanoid copepod Schmackeria poplesia, rotifer Brachionus plicatilis and anostraca crustacean Artemia sp. were analyzed for fatty acid contents, and were used as live food for culturing larval Japanese flounder, Paralichthys olivaceus. The total content of three types of HUFAs (DHA, EPA and ARA) in S. poplesia was significantly higher than that in the other two live foods ( P<0.01). Three live organisms were used for raising larvae and juveniles of Paralichthys olivaceus respectively for 15 and 10 d. Then the growth, survival and fatty acid composition of the larvae and juveniles were investigated. The results showed that the larvae and juveniles fed with copepods ( S. poplesia) had significantly higher growth rate than those fed with the other two organisms ( P<0.01). The survival of the flounder larvae fed with copepods was significantly higher than that of the others ( P<0.01), and the survival of the juvenile fish fed with copepods was higher than that fed with Artemia ( P<0.05). The contents of three types of HUFAs (DHA, EPA and ARA) and the ratio of DHA/EPA in larval and juvenile flounder P. olivaceus were analyzed. The results showed that the contents of DHA, EPA and ARA in the larvae and juveniles fed with S. poplesia were higher than those fed with a mixed diet or Artemia only, and the ratio of EPA/ARA in larvae and juveniles of P. olivaceus fed with S. poplesia was lower than that in the case of feeding with a mixed diet or Artemia only. The present data showed that copepod is the best choice for feeding the larvae and juveniles of fish considering its effects on the survival, growth and nutrition composition of the fish.

Liu, Guangxing; Xu, Donghui

2009-12-01

236

UV-B radiation-induced oxidative stress and p38 signaling pathway involvement in the benthic copepod Tigriopus japonicus.  

PubMed

Ultraviolet B (UV-B) radiation presents an environmental hazard to aquatic organisms. To understand the molecular responses of the intertidal copepod Tigriopus japonicus to UV-B radiation, we measured the acute toxicity response to 96h of UV-B radiation, and we also assessed the intracellular reactive oxygen species (ROS) levels, glutathione (GSH) content, and antioxidant enzyme (GST, GR, GPx, and SOD) activities after 24h of exposure to UV-B with LD50 and half LD50 values. Also, expression patterns of p53 and hsp gene families with phosphorylation of p38 MAPK were investigated in UV-B-exposed copepods. We found that the ROS level, GSH content, and antioxidant enzyme activity levels were increased with the transcriptional upregulation of antioxidant-related genes, indicating that UV-B induces oxidative stress by generating ROS and stimulating antioxidant enzymatic activity as a defense mechanism. Additionally, we found that p53 expression was significantly increased after UV-B irradiation due to increases in the phosphorylation of the stress-responsive p38 MAPK, indicating that UV-B may be responsible for inducing DNA damage in T. japonicus. Of the hsp family genes, transcriptional levels of hsp20, hsp20.7, hsp70, and hsp90 were elevated in response to a low dose of UV-B radiation (9kJm(-2)), suggesting that these hsp genes may be involved in cellular protection against UV-B radiation. In this paper, we performed a pathway-oriented mechanistic analysis in response to UV-B radiation, and this analysis provides a better understanding of the effects of UV-B in the intertidal benthic copepod T. japonicus. PMID:25152408

Kim, Bo-Mi; Rhee, Jae-Sung; Lee, Kyun-Woo; Kim, Min-Jung; Shin, Kyung-Hoon; Lee, Su-Jae; Lee, Young-Mi; Lee, Jae-Seong

2015-01-01

237

Temperature-dependent toxicities of four common chemical pollutants to the marine medaka fish, copepod and rotifer.  

PubMed

We hypothesize that chemical toxicity to marine ectotherms is the lowest at an optimum temperature (OT) and it exacerbates with increasing or decreasing temperature from the OT. This study aimed to verify this hypothetical temperature-dependent chemical toxicity (TDCT) model through laboratory experiments. Acute toxicity over a range of temperatures was tested on four commonly used chemicals to three marine ectotherms. Our results confirmed that toxicities, in terms of 96-h LC50 (median lethal concentration; for the marine medaka fish Oryzias melastigma and the copepod Tigriopus japonicus) and 24-h LC50 (for the rotifer Brachionus koreanus), were highly temperature-dependent, and varied between test species and between study chemicals. The LC50 value of the fish peaked at 20 °C for copper (II) sulphate pentahydrate and triphenyltin chloride, and at 25 °C for dichlorophenyltrichloroethane and copper pyrithione, and decreased with temperature increase or decrease from the peak (i.e., OT). However, LC50 values of the copepod and the rotifer generally showed a negative relationship with temperature across all test chemicals. Both copepod and rotifer entered dormancy at the lowest temperature of 4 °C. Such metabolic depression responses in these zooplanktons could reduce their uptake of the chemical and hence minimize the chemical toxicity at low temperatures. Our TDCT model is supported by the fish data only, whereas a simple linear model fits better to the zooplankton data. Such species-specific TDCT patterns may be jointly ascribed to temperature-mediated changes in (1) the physiological response and susceptibility of the marine ectotherms to the chemical, (2) speciation and bioavailability of the chemical, and (3) toxicokinetics of the chemical in the organisms. PMID:25098775

Li, Adela J; Leung, Priscilla T Y; Bao, Vivien W W; Yi, Andy X L; Leung, Kenneth M Y

2014-10-01

238

Maternal effects may act as an adaptation mechanism for copepods facing pH and temperature changes.  

PubMed

Acidification of the seas, caused by increased dissolution of CO(2) into surface water, and global warming challenge the adaptation mechanisms of marine organisms. In boreal coastal environments, temperature and pH vary greatly seasonally, but sometimes also rapidly within hours due to upwelling events. We studied if copepod zooplankton living in a fluctuating environment are tolerant to climate change effects predicted for 2100, i.e., a temperature increase of 3°C and a pH decrease of 0.4. Egg production of the copepod Acartia sp. was followed over five consecutive days at four temperature and pH conditions (17°C/ambient pH; 17°C/low pH; 20°C/ambient pH; 20°C/low pH). Egg production was higher in treatments with warmer temperature but the increase was smaller when copepods were simultaneously exposed to warmer temperature and lowered pH. To reveal if maternal effects are important in terms of adaptation to a changing environment, we conducted an egg transplantation experiment, where the produced eggs were moved to a different environment and egg hatching was monitored for three days. When pH changed between the egg production and hatching conditions, it resulted in lower hatching success, but the effect was diminished over the course of the experiment possibly due to improved maternal provisioning. Warmer egg production temperature induced a positive maternal effect and increased the egg hatching rate. Warmer hatching temperature resulted also in earlier hatching. However, the temperature effects appear to be dependent on the ambient sea temperature. Our preliminary results indicate that maternal effects are an important mechanism in the face of environmental change. PMID:23119052

Vehmaa, Anu; Brutemark, Andreas; Engström-Öst, Jonna

2012-01-01

239

Standard operating procedures for conducting acute and chronic aquatic toxicity tests with Eurytemora affinis, a calanoid copepod  

SciTech Connect

Eurytemora affinis, a calanoid copepod, was selected for standard toxicity testing protocol development subsequent to screening 25 resident Chesapeake Bay species including fish, invertebrates, and plants. Eurytemora was selected because of its ecological importance as an essential component in the trophic structure of the estuary, its relative practicability of culturing in the laboratory for year-round availability, and its sensitivity to toxic substances. The standards operating procedures described in this document provide detailed procedures for culturing, holding, and toxicity testing of E. affinis.

Ziegenfuss, M.C.; Hall, L.W.

1998-10-01

240

Effects of flow about a biologically produced structure on harpacticoid copepods in San Diego Trough  

NASA Astrophysics Data System (ADS)

Biologically produced structures located at the sediment-water interface may be important sources of environmental heterogeneity in the deep sea. We investigated the possibility that the interactions of such structures with flow affect abundances of sediment-dwelling harpacticoid copepods. The micro-topography of the seafloor at 1050 m depth in San Diego Trough is dominated by 2-3 cm diameter mud concretions (mudballs) built by the cirratulid polychaete Tharyx luticastellus. We compared patterns of abundance of harpacticoids about mudballs to patterns of shear stress produced by the deflection of flow around mudballs. Twelve of 37 spieces examined appeared to be sensitive to some consequence of flow about mudballs. For 11 of these 12 species, the sensitivity of harpacticoids to flow was associated with episodes of relatively strong currents, some of which occurred several to tens of hours prior to collection of the core. For four to eight of these 12 species some caveats to this interpretation are required because of concerns about multiple testing and the possibility that, for two species, processes unrelated to flow may have produced similar patterns of abundance. Some of the responding species were significantly more abundant within regions of increased shear stress about a mudball. We suspect that the higher abundances in these areas were produced by attraction of harpacticoids to regions of enhanced vertical transport of solutes. Other responding species were significantly more abundant within regions of decreased shear stress. The higher abundances within these areas probably represented passive accumulations of harpacticoids that were dispersed through the water column by stronger flows.

Eckman, James E.; Thistle, David

1991-11-01

241

Acute toxicity of naturally and chemically dispersed oil on the filter-feeding copepod Calanus finmarchicus.  

PubMed

Following oil spills in the marine environment, natural dispersion (by breaking waves) will form micron-sized oil droplets that disperse into the pelagic environment. Enhancing the dispersion process chemically will increase the oil concentration temporarily and result in higher bioavailability for pelagic organisms exposed to oil-dispersant plume. The toxicity of dispersed oil to pelagic organisms is a critical component in evaluating the net environmental consequences of dispersant use or non-use in open waters. To assess the potential for environmental effects, numerical models are being used, and for these to reliably predict the toxicity of chemically dispersed oil, it is essential to know if the dispersant affects the specific toxicity of the oil itself. In order to test the potential changes in specific toxicity of the oil due to the presence of chemical dispersant, copepods (Calanus finmarchicus) were subjected to a continuous exposure of chemically (4 percent Dasic w/w dispersant) and naturally dispersed oil (same droplet size range and composition) for four days. On average the addition of dispersant decreased 96h LC(50)-values by a factor of 1.6, while for LC(10) and LC(90) these factors were 2.9 and 0.9, respectively. This indicates that after 96h of exposure the dispersant slightly increased the specific toxicity of the oil at median and low effect levels, but reduced the toxicity at high effect levels. Decreased filtrations for the exposed groups were confirmed using particle counting and fluorescence microscopy. However, no differences in these endpoints were found between chemically and naturally dispersed oil. The ultimate goal was to evaluate if models used for risk and damage assessment can use similar specific toxicity for both chemically and naturally dispersed oil. The slight differences in toxicity between chemically and naturally dispersed oil suggest that risk assessment should be based on the whole concentration response curve to ensure survival of C. finmarchicus. PMID:23063079

Hansen, Bjørn Henrik; Altin, Dag; Olsen, Anders J; Nordtug, Trond

2012-12-01

242

Interpopulation patterns of divergence and selection across the transcriptome of the copepod Tigriopus californicus.  

PubMed

The accumulation of genetic incompatibilities between isolated populations is thought to lead to the evolution of intrinsic postzygotic isolation. The molecular basis for these mechanisms, however, remains poorly understood. The intertidal copepod Tigriopus californicus provides unique opportunities for addressing mechanistic questions regarding the early stages of speciation; hybrids between highly divergent populations are fertile and viable, but exhibit reduced fitness at the F(2) or later generations. Given the current scarcity of genomic information in taxa at incipient stages of reproductive isolation, we utilize high-throughout 454 pyrosequencing to characterize a substantial fraction of protein-coding regions (the transcriptome) of T. californicus. Our sequencing effort was divided equally between two divergent populations in order to estimate levels of divergence and to reveal patterns of selection across the transcriptome. Assembly of sequences generated over 40,000 putatively unique transcripts (unigenes) for each population, 19,622 of which were orthologous between populations. BLAST searches of public databases determined protein identity and functional features for 15,402 and 12,670 unigenes, respectively. Based on rates of nonsynonymous and synonymous substitutions in 5897 interpopulation orthologs (those >150 bp and with at least 2X coverage), we identified 229 potential targets of positive selection. Many of these genes are predicted to be involved in several metabolic processes, and to function in hydrolase, peptidase and binding activities. The library of T. californicus coding regions, annotated with their predicted functions and level of divergence, will serve as an invaluable resource for elucidating molecular mechanisms underlying the early stages of speciation. PMID:21199025

Barreto, Felipe S; Moy, Gary W; Burton, Ronald S

2011-02-01

243

Evolution of interacting proteins in the mitochondrial electron transport system in a marine copepod.  

PubMed

The extensive interaction between mitochondrial-encoded and nuclear-encoded subunits of electron transport system (ETS) enzymes in mitochondria is expected to lead to intergenomic coadaptation. Whether this coadaptation results from adaptation to the environment or from fixation of deleterious mtDNA mutations followed by compensatory nuclear gene evolution is unknown. The intertidal copepod Tigriopus californicus shows extreme divergence in mtDNA sequence and provides an excellent model system for study of intergenomic coadaptation. Here, we examine genes encoding subunits of complex III of the ETS, including the mtDNA-encoded cytochrome b (CYTB), the nuclear-encoded rieske iron-sulfur protein (RISP), and cytochrome c(1) (CYC1). We compare levels of polymorphism within populations and divergence between populations in these genes to begin to untangle the selective forces that have shaped evolution in these genes. CYTB displays dramatic divergence between populations, but sequence analysis shows no evidence for positive selection driving this divergence. CYC1 and RISP have lower levels of sequence divergence between populations than CYTB, but, again, sequence analysis gives no evidence for positive selection acting on them. However, an examination of variation at cytochrome c (CYC), a nuclear-encoded protein that transfers electrons between complex III and complex IV provides evidence for selective divergence. Hence, it appears that rapid evolution in mitochondrial-encoded subunits is not always associated with rapid divergence in interacting subunits (CYC1 and RISP), but can be in some cases (CYC). Finally, a comparison of nuclear-encoded and mitochondrial-encoded genes from T. californicus suggests that substitution rates in the mitochondrial-encoded genes are dramatically increased relative to nuclear genes. PMID:14660687

Willett, Christopher S; Burton, Ronald S

2004-03-01

244

Unusual structure of ribosomal DNA in the copepod Tigriopus californicus: intergenic spacer sequences lack internal subrepeats.  

PubMed

Eukaryotic nuclear ribosomal DNA (rDNA) is typically arranged as a series of tandem repeats coding for 18S, 5.8S, and 28S ribosomal RNAs. Transcription of rDNA repeats is initiated in the intergenic spacer (IGS) region upstream of the 18S gene. The IGS region itself typically consists of a set of subrepeats that function as transcriptional enhancers. Two important evolutionary forces have been proposed to act on the IGS region: first, selection may favor changes in the number of subrepeats that adaptively adjust rates of rDNA transcription, and second, coevolution of IGS sequence with RNA polymerase I transcription factors may lead to species specificity of the rDNA transcription machinery. To investigate the potential role of these forces on population differentiation and hybrid breakdown in the intertidal copepod Tigriopus californicus, we have characterized the rDNA of five T. californicus populations from the Pacific Coast of North America and one sample of T. brevicornicus from Scotland. Major findings are as follows: (1) the structural genes for 18S and 28S are highly conserved across T. californicus populations, in contrast to other nuclear and mitochondrial DNA (mtDNA) genes previously studied in these populations. (2) There is extensive differentiation among populations in the IGS region; in the extreme, no homology is observed across the IGS sequences (>2 kb) from the two Tigriopus species. (3) None of the Tigriopus IGS sequences have the subrepeat structure common to other eukaryotic IGS regions. (4) Segregation of rDNA in laboratory crosses indicates that rDNA is located on at least two separate chromosomes in T. californicus. These data suggest that although IGS length polymorphism does not appear to play the adaptive role hypothesized in some other eukaryotic systems, sequence divergence in the rDNA promoter region within the IGS could lead to population specificity of transcription in hybrids. PMID:15656977

Burton, R S; Metz, E C; Flowers, J M; Willett, C S

2005-01-01

245

Lipid and fatty acid composition of parasitic caligid copepods belonging to the genus Lepeophtheirus.  

PubMed

Sea lice are copepod ectoparasites that constitute a major barrier to the sustainability and economic viability of marine finfish aquaculture operations worldwide. In particular, the salmon louse, Lepeophtheirus salmonis, poses a considerable problem for salmoniculture in the northern hemisphere. The free-swimming nauplii and infective copepodids of L. salmonis are lecithotrophic, subsisting principally on maternally-derived lipid reserves. However, the lipids and fatty acids of sea lice have been sparsely studied and therefore the present project aimed to investigate the lipid and fatty acid composition of sea lice of the genus Lepeophtheirus obtained from a variety of fish hosts. Total lipid was extracted from eggs and adult female L. salmonis obtained from both wild and farmed Atlantic salmon (Salmo salar L.) sampled at two time points, in the mid 1990s and in 2009. In addition, L. salmonis from wild sea trout (Salmo trutta L.) and L. hippoglossi from wild Atlantic halibut (Hippoglossus hippoglossus L.) were sampled and analyzed. The lipids of both females and egg strings of Lepeophtheirus were characterized by triacylglycerol (TAG) as the major neutral (storage) lipid with phosphatidylcholine and phosphatidylethanolamine as the major polar (membrane) lipids. The major fatty acids were 22:6n-3 (DHA), 18:1n-9 and 16:0, with lesser amounts of 20:5n-3, 22:5n-3 and 18:0. L. salmonis sourced from farmed salmon was characterized by higher levels of 18:2n-6 and 18:3n-3 than lice from wild salmon. Egg strings had higher levels of TAG and lower DHA compared to females, whereas L. hippoglossi had lower levels of TAG and higher DHA than L. salmonis. The results demonstrate that the fatty acid compositions of lice obtained from wild and farmed salmon differ and that changes to the lipid and fatty acid composition of feeds for farmed salmon influence the louse compositions. PMID:20206710

Tocher, J A; Dick, J R; Bron, J E; Shinn, A P; Tocher, D R

2010-06-01

246

Copepod grazing and fine-scale distribution patterns during the Marine Light-Mixed Layers experiment  

NASA Astrophysics Data System (ADS)

The mesozooplankton in the upper 100 m at 59°N, 21°W were dominated by the copepodite stages of Calanus finmarchicus in both May and August 1991. Abundance of C. finmarchicus in the upper 20 m of the water column was 800 m-3 in May and 200 m-3 in August. Although hydrographic conditions changed from well mixed to stratified between May and August, the fine-scale vertical distribution pattern of C. finmarchicus was essentially the same during these two surveys of the Marine Light-Mixed Layers site. Copepodite stage five (CV) comprised a larger fraction of the population in August compared to May, however. Gut evacuation experiments with C. finmarchicus indicated that late copepodite and adult female life stages had evacuation rates of approximately 4% h-1 in both May and August. Although these evacuation rates are consistent with others measured for Calanus, the relatively low biomass in the upper 100 m resulted in an estimated daily grazing impact by Calanus of less than 5 % of the phytoplankton standing stock in May, and less than 1% in August. The ingestion rates we measured suggest that the total grazing impact of all mesozooplankton grazers is less than 10% of daily primary production. These relatively low ingestion rates on phytoplankton provide these copepods with less than half of the total daily carbon intake required to balance estimated rates of respiration and growth in the field. In order to balance these metabolic costs, we estimate that the mesozooplankton would need to ingest the equivalent of at least 100% of the estimated microzooplankton/protist daily production.

Cowles, Timothy J.; Fessenden, Lynne M.

1995-04-01

247

Diurnal feeding rhythms in north sea copepods measured by Gut fluorescence, digestive enzyme activity and grazing on labelled food  

NASA Astrophysics Data System (ADS)

Results obtained with three methods for measuring feeding rhythms of copepods were different. Gut fluorescence showed clear day-night variation during 2 out of 3 cruises at the Oyster Ground in the North Sea. The species studied ( Pseudocalanus, Temora, Centropages, Calanus) had highest gut fluorescence during the night in May and September, the larger species demonstrating the largest difference. Gut fluorescence was positively correlated with ambient chlorophyll concentrations. Gut clearance rate was not dependent on temperature but on gut fullness. Gut passage times at high gut fluorescence levels were ˜25 minutes, at low levels 2 hours. In grazing experiments with 14C labelled food, filtering rates declined after 5 to 15 minutes, presumably before the first defecation of radioactive material. Filtering rates in Temora were higher at night than by day during May and July, but not in Pseudocalanus and Calanus during September. No diurnal pattern of amylase and tryptic activity was found, except in July for amylase but then probably due to vertical migration. The activity of these digestive enzymes appeared to be least and gut fluorescence most suitable for the detection of grazing rhythms. The occurrence of high fluorescence levels at night in all species studied suggests that intermittent feeding by copepods on phytoplankton is a general phenomenon from spring to autumn. The increase in foraging activity appeared to start well before complete darkness, during May and July even one hour or more before sunset.

Baars, M. A.; Oosterhuis, S. S.

248

Physiological effects of an allozyme polymorphism: glutamate-pyruvate transaminase and response to hyperosmotic stress in the copepod Tigriopus californicus.  

PubMed

In order to regulate cell volume during hyperosmotic stress, the intertidal copepod Tigriopus californicus, like other aquatic crustaceans, rapidly accumulates high levels of intracellular alanine, proline, and glycine. Glutamate-pyruvate transaminase (GPT; EC 2.6.1.2), which catalyzes the final step of alanine synthesis, is genetically polymorphic in T. californicus populations at Santa Cruz, California. Spectrophotometric studies of homogenates derived from a homozygous isofemale line of each of the two common GPT alleles indicated that the GPTF allozyme has a significantly higher specific activity than the GPTS allozyme. Under conditions of hyperosmotic stress, individual adult copepods of GPTF and GPTF/S genotypes accumulated alanine, but not glycine or proline, more rapidly than GPTS homozygotes. When young larvae were subjected to the same hyperosmotic conditions, GPTS larvae suffered a significantly higher mortality than GPTF or GPTF/S larvae. These results suggest that the biochemical differences among GPT allozymes result in specific physiological variation among GPT genotypes and that this physiological variation is manifested in differential genotypic survivorships under some naturally occurring environmental conditions. PMID:6860293

Burton, R S; Feldman, M W

1983-04-01

249

Plankton community diversity from bacteria to copepods in bloom and non-bloom conditions in the Celtic Sea in spring  

NASA Astrophysics Data System (ADS)

The plankton community composition comprising heterotrophic bacteria, pro-/eukaryotes, heterotrophic nanoflagellates, microzooplankton and mesozooplankton was assessed during the spring bloom and at non-bloom stations in the English Channel and Celtic Sea between 6 and 12 April 2002. Non-bloom sites were characterised by a dominance of pro-/eukaryotic phytoplankton <20 ?m, higher abundance of heterotrophic nanoflagellates, microzooplankton standing stocks ranging between 60 and 380 mg C m -2, lower mesozooplankton diversity and copepod abundance of between 760 and 2600 ind m -3. Within the bloom, the phytoplankton community was typically dominated by larger cells with low abundance of pro-/eukaryotes. Heterotrophic nanoflagellate cell bio-volume decreased leading to a reduction in biomass whereas microzooplankton biomass increased (360-1500 mg C m -2) due to an increase in cell bio-volume and copepod abundance ranged between 1400 and 3800 ind m -3. Mesozooplankton diversity increased with an increase in productivity. Relationships between the plankton community and environmental data were examined using multivariate statistics and these highlighted significant differences in the abiotic variables, the pro-/eukaryotic phytoplankton communities, heterotrophic nanoflagellate, microzooplankton and total zooplankton communities between the bloom and non-bloom sites. The variables which best described variation in the microzooplankton community were temperature and silicate. The spatial variation in zooplankton diversity was best explained by temperature. This study provides an insight into the changes that occur between trophic levels within the plankton in response to the spring bloom in this area.

Fileman, Elaine S.; Fitzgeorge-Balfour, Tania; Tarran, Glen A.; Harris, Roger P.

2011-07-01

250

The importance of uptake from food for the bioaccumulation of PCB and PBDE in the marine planktonic copepod Acartia clausi.  

PubMed

The accumulation of (14)C-labelled PCB 31, PCB 101, PCB 153 and PBDE 99 was investigated at the two lowest trophic levels of the pelagic food web. Accumulation was measured in the small phytoplankter Thalassiosira weissflogii (Coscinodiscophyceae: Thalassiosirales) and in the neritic zooplankter Acartia clausi (Copepoda: Calanoida) exposed to the substance either only via water or through ingestion of contaminated T. weissflogii. Bioaccumulation factors (BAFs) for all four compounds were significantly higher in A. clausi feeding on contaminated phytoplankton than in animals exposed only via water. The logBAF for the PCBs increased linearly with the octanol-water partitioning coefficients (logK(OW)) in both the algae and the copepods, but with steeper slopes for feeding than non-feeding animals. Reported values for K(OW) for PBDEs vary by almost an order of magnitude and it was therefore not meaningful to calculate a logBAF-logK(OW) ratio for PBDE 99. It is clear that the nutritional status of the zooplankton affects the uptake of the compounds and that the bioaccumulation cannot be modelled as a passive partitioning between the organisms and the surrounding water. Small copepods are typical of coastal waters and point sources (both temporal and spatial) may be the rule for HOC releases into the sea. Thus, the pathways shown in this study are important and realistic. PMID:20400188

Magnusson, Kerstin; Tiselius, Peter

2010-07-15

251

Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to Zostera noltii beds  

NASA Astrophysics Data System (ADS)

This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments, using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos is among the main resources of most taxa, but seagrass-associated resources (i.e. seagrass detritus and epiphytes) also contribute to meiobenthos nutrition, with seagrass detritus being available also in deeper sediments and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders) according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

Vafeiadou, A.-M.; Materatski, P.; Adão, H.; De Troch, M.; Moens, T.

2014-01-01

252

Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to Zostera noltii beds  

NASA Astrophysics Data System (ADS)

This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos and/or epiphytes are among the main resources of most taxa, but seagrass detritus and sediment particulate organic matter contribute as well to meiobenthos nutrition, which are also available in deeper sediment layers and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders) according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that the interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

Vafeiadou, A.-M.; Materatski, P.; Adão, H.; De Troch, M.; Moens, T.

2014-07-01

253

Copepod feeding and reproduction in relation to phytoplankton development during the PeECE III mesocosm experiment  

NASA Astrophysics Data System (ADS)

Within the frame of the Pelagic Ecosystem CO2 Enrichment (PeECE III) experiment, reproduction and feeding of the copepod Calanus finmarchicus was monitored in relation to phytoplankton development in two mesocosms, at present 1× (350 ?atm) and ca 3× present (1050 ?atm) CO2 concentrations, respectively. Both mesocosms showed rapid phytoplankton growth after the initial nutrient additions and reached maximum chlorophyll (Chl) a concentrations around day 10. Flow-cytometry and specific pigment analysis (HPLC-CHEMTAX), showed that diatoms and prymnesiophyceae (Emiliania huxleyi (Ehux) and other nanoplankton) dominated the biomass. Feeding and egg production rates of C. finmarchicus developed similarly in both mesocosms, and were positively correlated with Chla, Ehux, diatom and prymnesiophyceae concentrations. Although the total number of copepod nauplii recruited during the experiment was similar in 1× and 3×, significantly less nauplii were recruited in 3× during the peak of the bloom compared to in 1×. We conclude that the algae responsible for the higher biomass in 3× during the peak of the bloom (diatoms and Ehux), may have been relatively inferior food for C. finmarchicus naupliar recruitment, possibly due to a high C:N ratio (>8). Nevertheless, the 3 fold increase in CO2 concentration did not show any clear overall effect on bulk phytoplankton or zooplankton development over the whole experiment, suggesting a more complex coupling between increased CO2 and the nutritional status of the system.

Carotenuto, Y.; Putzeys, S.; Simonelli, P.; Paulino, A.; Meyerhöfer, M.; Suffrian, K.; Antia, A.; Nejstgaard, J. C.

2007-10-01

254

Positive effects of UV radiation on a calanoid copepod in a transparent lake: do competition, predation or food availability play a role?  

Microsoft Academic Search

Zooplankton tolerant to ultraviolet radiation (UVR) could be indirectly affected by UVR through interactions with UV-sensitive species in the same ecosystem. In Lake Giles, Pennsylvania, USA, the calanoid copepod Leptodiaptomus minutus is more UVR tolerant than the cohabiting species Daphnia catawba and Cyclops scutifer. We asked whether L. minutus is affected by UV-induced mortality of a food competitor (D. catawba)

SANDRA L. COOKE; CRAIG E. WILLIAMSON

2005-01-01

255

Tech Quantitative Analysis of Tethered Versus Free-Swimming Copepod Flow Fields Kimberly B. Catton1 , Donald R. Webster1, Jason Brown2, and  

E-print Network

the differences in the flow fields generated by tethered and free-swimming Euchaeta antarctica (CV copepodids). The effect of a point force on a fluid shows that changes in the flow field between tethered and free Euchaeta antarctica is a predatory copepod found in the Southern Ocean near Antarctica Flow fields were

256

Ingestion, gut passage, and egestion by the copepod Neocalanus plumchrus in the laboratory and in the subarctic Pacific 0cean1v2  

Microsoft Academic Search

The relationships between ingestion rate, gut content, gut passage time, and egestion rate in the copepod Neocalanus plumchrus were determined in laboratory experiments over a wide range of food concentrations. Ingestion, gut content, and egestion were related to food concentration in a rectilinear manner; increases were linear up to about 4.0 pg Chl liter-' of Thalassiosira weissflogii and constant at

Michael J. Dagg; W. Edward Waker

1987-01-01

257

Contrasting effects of a cladoceran ( Daphnia galeata ) and a calanoid copepod ( Eodiaptomus japonicus ) on algal and microbial plankton in a Japanese lake, Lake Biwa  

Microsoft Academic Search

Macrozooplankton may affect algal and microbial plankton directly through grazing or predation and indirectly through nutrient regeneration. They may also affect potential prey positively by removing alternative predators. Here, we examined the effects of a cladoceran (Daphnia) and a calanoid copepod (Eodiaptomus) on algal and microbial plankton in a Japanese lake using in situ experiments in which we manipulated the

Takehito Yoshida; Tek Bahadur Gurung; Maiko Kagami; Jotaro Urabe

2001-01-01

258

Three divergent mitochondrial genomes from California populations of the copepod Tigriopus californicus.  

PubMed

Previous work on the harpacticoid copepod Tigriopus californicus has focused on the extensive population differentiation in three mtDNA protein coding genes (COXI, COXII, Cytb). In order to get a more complete understanding of mtDNA evolution in this species, we sequenced three complete mitochondrial genomes (one from each of three California populations) and compared them to two published mtDNA genomes from an Asian congener, Tigriopus japonicus. Several features of the mtDNA genome appear to be conserved within the genus: 1) the unique order of the protein coding genes, rRNA genes and most of the tRNA genes, 2) the genome is compact, varying between 14.3 and 14.6 kb, and 3) all genes are encoded on the same strand of the mtDNA. Within T. californicus, extremely high levels of nucleotide divergence (>20%) are observed across much of the mitochondrial genome. Inferred amino acid sequences of the proteins encoded in the mtDNAs also show high levels of divergence; at the extreme, the three ND3 variants in T. californicus showed >25% amino acid substitutions, compared with <3% amino acid divergence at the previously studied COXI locus. Unusual secondary structures make functional assignments of some tRNAs difficult. The only apparent tRNA(trp) in these genomes completely overlaps the 5' end of the 16S rRNA in all three T. californicus mtDNAs. Although not previously noted, this feature is also conserved in T. japonicus mtDNAs; whether this sequence is processed into a functional tRNA has not been determined. The putative control region contains a duplicated segment of different length (from 88 to 155 bp) in each of the T. californicus sequences. In each case, the duplicated segments are not tandem repeats; despite their different lengths, the distance between the start of the first and the start of the second repeat is conserved (520 bp). The functional significance, if any, of this repeat structure remains unknown. PMID:17855023

Burton, Ronald S; Byrne, Rosemary J; Rawson, Paul D

2007-11-15

259

Distinctive mitochondrial genome of Calanoid copepod Calanus sinicus with multiple large non-coding regions and reshuffled gene order: Useful molecular markers for phylogenetic and population studies  

PubMed Central

Background Copepods are highly diverse and abundant, resulting in extensive ecological radiation in marine ecosystems. Calanus sinicus dominates continental shelf waters in the northwest Pacific Ocean and plays an important role in the local ecosystem by linking primary production to higher trophic levels. A lack of effective molecular markers has hindered phylogenetic and population genetic studies concerning copepods. As they are genome-level informative, mitochondrial DNA sequences can be used as markers for population genetic studies and phylogenetic studies. Results The mitochondrial genome of C. sinicus is distinct from other arthropods owing to the concurrence of multiple non-coding regions and a reshuffled gene arrangement. Further particularities in the mitogenome of C. sinicus include low A + T-content, symmetrical nucleotide composition between strands, abbreviated stop codons for several PCGs and extended lengths of the genes atp6 and atp8 relative to other copepods. The monophyletic Copepoda should be placed within the Vericrustacea. The close affinity between Cyclopoida and Poecilostomatoida suggests reassigning the latter as subordinate to the former. Monophyly of Maxillopoda is rejected. Within the alignment of 11 C. sinicus mitogenomes, there are 397 variable sites harbouring three 'hotspot' variable sites and three microsatellite loci. Conclusion The occurrence of the circular subgenomic fragment during laboratory assays suggests that special caution should be taken when sequencing mitogenomes using long PCR. Such a phenomenon may provide additional evidence of mitochondrial DNA recombination, which appears to have been a prerequisite for shaping the present mitochondrial profile of C. sinicus during its evolution. The lack of synapomorphic gene arrangements among copepods has cast doubt on the utility of gene order as a useful molecular marker for deep phylogenetic analysis. However, mitochondrial genomic sequences have been valuable markers for resolving phylogenetic issues concerning copepods. The variable site maps of C. sinicus mitogenomes provide a solid foundation for population genetic studies. PMID:21269523

2011-01-01

260

CellTracker Green labelling vs. Rose Bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodes  

NASA Astrophysics Data System (ADS)

Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week) in the Northern Adriatic Sea, Mediterranean, and examined the two most abundant meiofauna taxa - harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG) - new labelling approach for meiofauna - with the traditional Rose Bengal (RB) staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. Surprisingly, RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more fine-scaled (days, hours, tipping points) studies, especially on hypoxia and anoxia where it is necessary to resolve the course of events, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.

Grego, M.; Stachowitsch, M.; De Troch, M.; Riedel, B.

2013-02-01

261

CellTracker Green labelling vs. rose bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodes  

NASA Astrophysics Data System (ADS)

Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week) in the northern Adriatic Sea (Mediterranean) and examined the two most abundant meiofauna taxa - harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG) - new labelling approach for meiofauna - with the traditional rose bengal (RB) staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as it does live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more precise quantification of community degradation, especially after an oxygen depletion event, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.

Grego, M.; Stachowitsch, M.; De Troch, M.; Riedel, B.

2013-07-01

262

Effects of elevated pCO2 on reproductive properties of the benthic copepod Tigriopus japonicus and gastropod Babylonia japonica.  

PubMed

We investigated the effects of elevated pCO2 in seawater both on the acute mortality and the reproductive properties of the benthic copepod Tigriopus japonicus and gastropod Babylonia japonica with the purpose of accumulating basic data for assessing potential environmental impacts of sub-sea geological storage of anthropogenic CO2 in Japan. Acute tests showed that nauplii of T. japonicus have a high tolerance to elevated pCO2 environments. Full life cycle tests on T. japonicus indicated NOEC=5800?atm and LOEC=37,000?atm. Adult B. japonica showed remarkable resistance to elevated pCO2 in the acute tests. Embryonic development of B. japonica showed a NOEC=1500?atm and LOEC=5400?atm. T. japonicus showed high resistance to elevated pCO2 throughout the life cycle and B. japonica are rather sensitive during the veliger stage when they started to form their shells. PMID:23820193

Kita, Jun; Kikkawa, Takashi; Asai, Takamasa; Ishimatsu, Atsushi

2013-08-30

263

Linkage relationships among five enzyme-coding gene loci in the copepod Tigriopus californicus: a genetic confirmation of achiasmiatic meiosis.  

PubMed

Linkage relationships among five polymorphic enzyme-coding gene loci in the marine copepod Tigriopus californicus have been determined using electrophoretic analysis of progeny from laboratory matings. Phosphoglucose isomerase (PGI; EC 5.3.1.9) was found to be tightly linked to glutamate-pyruvate transaminase (GPT; EC 2.6..1.2), with only one recombinant observed in 364 progeny; glutamate-oxaloacetate transaminase (GOT; EC 2.6.1.1) is linked to the PGI-GPT pair, with a recombination fraction of approximately 0.20 in male double heterozygotes. Phosphoglucomutase (PGM; EC 2.7.5.1) and an esterase (EST; EC 3.1.1.1) are not linked to the PGI, GPT, GOT grouping, which has been designated linkage group I. Reciprocal crosses have revealed that no recombination occurs in female T. californicus; this observation confirms a previous report that meiosis in female Tigriopus is achiasmatic. PMID:6461328

Burton, R S; Feldman, M W; Swisher, S G

1981-12-01

264

Effect of bis(tributyltin) oxide on reproduction and population growth rate of calanoid copepod Schmackeria poplesia  

NASA Astrophysics Data System (ADS)

A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L-1 were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1. The percentages of ovigerous females were reduced compared with the control ( P<0.01) after 24 days exposure to concentrations higher than 10 ng TBTO L-1. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase ( r m), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration (60 ng L-1), where all females aborted their egg sacs, 20 ng TBTO L-1 was the only concentration that significantly decreased r m compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.

Huang, Ying; Zhu, Liyan; Qiu, Xuchun; Zhang, Tianwen

2010-03-01

265

Quantifying the elevation of mitochondrial DNA evolutionary substitution rates over nuclear rates in the intertidal copepod Tigriopus californicus.  

PubMed

Mitochondrial DNA (mtDNA) genomes generally evolve rapidly in animals, but considerable variation in the rates of evolution of mtDNA occurs among taxa. Higher levels of mutation will tend to increase the amount of polymorphism, which should also scale with population size, but there are mixed signals from previous studies on the evolutionary outcomes of the interactions of these processes. The copepod Tigriopus californicus provides an interesting model in which to study the evolution of mtDNA because it has high levels of divergence among populations and there is the suggestion that this divergence could be involved in reproductive isolation. This species also appears to have an elevated mtDNA substitution rate, but previous studies did not provide an accurate measurement. This article examines the rate of mtDNA substitution versus nuclear substitution in T. californicus and finds that the mtDNA rate for synonymous sites averages 55-fold higher, a level that exceeds the rates found in most other invertebrates. Levels of polymorphism are also examined in both mtDNA and nuclear genes, and it is shown that the effective population size of mtDNA genes is much lower than that of nuclear genes. In addition, no correlation between polymorphism in mtDNA and nuclear genes is found across populations, which suggest factors other than demography may shape polymorphism in this species. The results from this study suggest that mtDNA is evolving at a very rapid rate in this copepod species, and this could increase the likelihood that mtDNA evolution is involved in the generation of reproductive isolation. PMID:22760646

Willett, Christopher S

2012-06-01

266

Multiple gene analyses of caligid copepods indicate that the reduction of a thoracic appendage in Pseudocaligus represents convergent evolution  

PubMed Central

Background The Caligidae is a family of parasitic copepods containing over 30 recognised genera. They are commercially important parasites as they cause disease in numerous finfish aquaculture facilities globally. Morphological features are used to distinguish between the genera and Pseudocaligus has traditionally been differentiated from Caligus solely by the presence of a much reduced form of the fourth thoracic leg. Currently there are numerous DNA sequences available for Caligus spp. but only the type species, Pseudocaligus brevipedis, has molecular data available, so systematic studies using molecular phylogenetic analyses have been limited. Methods Three gene regions, SSU rDNA, 16S and CO1, for Pseudocaligus fugu from puffer fish from Japan and Pseudocaligus uniartus from rabbit fish from Indonesia are sequenced and molecular phylogenetic analyses performed in order to infer phylogenetic relationships between Pseudocaligus and other caligid copepods. Results The analysis revealed that there was no discrete grouping of Pseudocaligus spp. and that they had a polyphyletic distribution within Caligus taxa. Pseudocaligus fugu grouped with Caligus elongatus and contained a unique synapomorphy in the SSU rDNA region only seen in members of that clade. Pseudocaligus uniartus formed a well-supported group, in the SSU rDNA analyses, with a Caligus sp. that also infects rabbit fish, but was unresolved in the other analyses. Pseudocaligus brevipedis consistently and robustly grouped with Caligus curtus and C. centrodonti in all analyses. The majority of Lepeophtheirus spp. form a monophyletic sister group to the Caligus clade; however, L. natalensis is unresolved in all analyses and does not form part of the main Lepeophtheirus clade. Conclusions These findings do not support the morphological-based distinction between Pseudocaligus and Caligus, suggesting that the reduced fourth leg is a feature that has evolved on multiple occasions throughout caligid evolution. Congruent molecular phylogenetic data support groupings based on the presence of morphological features, such as lunules, geography and host fish type rather than appendage morphology. Therefore, we support the synonymy of Pseudocaligus with Caligus. PMID:24286135

2013-01-01

267

Closely linked H2B genes in the marine copepod, Tigriopus californicus indicate a recent gene duplication or gene conversion event.  

PubMed

Two nonallelic histone gene clusters were characterized in the marine copepod, Tigriopus californicus. The DNA sequence of one of the clusters reveals six genes in the contiguous arrangement of H2B, H1, H3, H4, H2B and H2A. The order of genes within the second cluster is H3, H4, H2B and H2A. There is no evidence for the presence of an H1 gene in this cluster. Comparison of the three copepod H2B genes reveals a high degree of similarity between the 5' upstream regions and between the amino terminal halves of the two H2B genes found within the same cluster. From these data we infer that gene duplication and/or gene conversion events occurred within this cluster in the recent past. PMID:1446074

Brown, D; Cook, A; Wagner, M; Wells, D

1992-01-01

268

Impact of the Gabcíkovo hydropower plant operation on planktonic copepods assemblages in the River Danube and its floodplain downstream of Bratislava  

Microsoft Academic Search

The structure of planktonic copepod assemblages in a by-passedDanube section, and in the adjacent floodplain water bodies,haschanged since the Gabcíkovo hydropower plant was putintooperation. The greatest change occurred in a former side arm(upstream of the village of Dobrohosí), which driedout.Changes were observed in the parapotamon-type side armssituatedbetween river km 1840 and 1820, fed artificially with waterfromthe head-race canal. The abundance

Marian Vranovský

1997-01-01

269

Distribution and feeding of Benthosema glaciale in the western Labrador Sea: Fish-zooplankton interaction and the consequence to calanoid copepod populations  

NASA Astrophysics Data System (ADS)

This study evaluated the distribution of major calanoid copepods in the western Labrador Sea in relation to that of the myctophid Benthosema glaciale, and investigated patterns of prey composition and feeding periodicity by the latter to assess the potential impact of mesopelagic fish on copepod populations that reside in the deep ocean. Hydroacoustic surveys indicated that B. glaciale and the deep-scattering layer are widely distributed throughout the region with limited evidence of patchiness, with an average abundance of 6 fish m-2 and biomass of 9.3 g m-2. There was clear evidence of diurnal variations in feeding activity that was achieved through vertical migration from several hundred meters depths to the surface layer. B. glaciale fed principally on calanoid copepods, with prey size dependent on the length of the fish but the relative variability in prey size was independent of predator length. Average rations were generally less than 1% of body weight per day, and the patterns of diurnal vertical migration by myctophids suggest that individuals fed once every two days rather than daily. The estimated mortality caused by B. glaciale on the calanoid populations, which considers most sources of uncertainty, ranged from 0.002 to 1.8% d-1, with the mid-point of these estimates being ˜0.15% d-1, which is well below the estimated mortality rates of 10-20% d-1 based on vertical life tables. From observations from this and other ecosystems, understanding and contrasting the drivers of population dynamics and productivity of calanoid copepods in different deep basins of the North Atlantic will likely require a more comprehensive characterization of the plankton and pelagic and oceanic fish faunas of the epipelagic and mesopelagic zones and their trophic relationships and interactions.

Pepin, Pierre

2013-05-01

270

Heavy metals induce oxidative stress and trigger oxidative stress-mediated heat shock protein (hsp) modulation in the intertidal copepod Tigriopus japonicus.  

PubMed

Heat shock proteins (hsps) are induced by a wide range of environmental stressors including heavy metals in aquatic organisms. However, the effect of heavy metals on zooplankton at the molecular level remains still unclear. In this study, we measured the intracellular reactive oxygen species (ROS) level and the antioxidant enzyme activities for 96h after exposure to five heavy metals: arsenic (As), cadmium (Cd), copper (Cu), silver (Ag), and zinc (Zn) in the intertidal copepod Tigriopus japonicus. Activities of the antioxidant enzymes were highly elevated in metal-exposed copepods, indicating that heavy metals can induce oxidative stress by generating ROS, and stimulate the involvement of antioxidant enzymes as cellular defense mechanisms. Subsequently, transcriptional changes in hsp gene families were further investigated in the metal-exposed groups for 96h. The ROS level and glutathione (GSH) content were significantly increased in Ag-, As-, and Cu-exposed copepods, while they were only slightly elevated in Cd- and Zn-exposed groups. Based on the numbers of significantly modulated hsp genes and their expression levels for 96h, we measured the effect of heavy metals to stress genes of T. japonicus in the following order: Cu>Zn>Ag>As>Cd, implying that Cu acts as a stronger oxidative stress inducer than other heavy metals. Of them, the expression of hsp20 and hsp70 genes was substantially modulated by exposure to heavy metals, indicating that these genes would provide a sensitive molecular biomarker for aquatic monitoring of heavy metal pollution. PMID:25058597

Kim, Bo-Mi; Rhee, Jae-Sung; Jeong, Chang-Bum; Seo, Jung Soo; Park, Gyung Soo; Lee, Young-Mi; Lee, Jae-Seong

2014-11-01

271

Eucalanoid copepod metabolic rates in the oxygen minimum zone of the eastern tropical north Pacific: Effects of oxygen and temperature  

NASA Astrophysics Data System (ADS)

The eastern tropical north Pacific Ocean (ETNP) contains one of the world's most severe oxygen minimum zones (OMZs), where oxygen concentrations are less than 2 ?mol kg-1. OMZs cause habitat compression, whereby species intolerant of low oxygen are restricted to near-surface oxygenated waters. Copepods belonging to the family Eucalanidae are dominant zooplankters in this region and inhabit a variety of vertical habitats within the OMZ. The purpose of this study was to compare the metabolic responses of three species of eucalanoid copepods, Eucalanus inermis, Rhincalanus rostrifrons, and Subeucalanus subtenuis, to changes in temperature and environmental oxygen concentrations. Oxygen consumption and urea, ammonium, and phosphate excretion rates were measured via end-point experiments at three temperatures (10, 17, and 23 °C) and two oxygen concentrations (100% and 15% air saturation). S. subtenuis, which occurred primarily in the upper 50 m of the water column at our study site, inhabiting well-oxygenated to upper oxycline conditions, had the highest metabolic rates per unit weight, while E. inermis, which was found throughout the water column to about 600 m depth in low oxygen waters, typically had the lowest metabolic rates. Rates for R. rostrifrons (found primarily between 200 and 300 m depth) were intermediate between the other two species and more variable. Metabolic ratios suggested that R. rostrifrons relied more heavily on lipids to fuel metabolism than the other two species. S. subtenuis was the only species that demonstrated a decrease in oxygen consumption rates (at intermediate 17 °C temperature treatment) when environmental oxygen concentrations were lowered. The percentage of total measured nitrogen excreted as urea (% urea-N), as well as overall urea excretion rates, responded in a complex manner to changes in temperature and oxygen concentration. R. rostrifrons and E. inermis excreted a significantly higher % of urea-N in low oxygen treatments at 10 °C. At 17 °C, the opposite trend was observed as E. inermis and S. subtenuis excreted a higher % of urea-N in the high oxygen treatment. This unique relationship has not been documented previously for crustacean zooplankton, and warrants additional research into regulation of metabolic pathways to better understand nitrogen cycling in marine systems. This study also compared metabolic data for E. inermis individuals captured near the surface versus those that were resident in the deeper OMZ. Deeper-dwelling individuals had significantly higher nitrogen excretion rates and O:N ratios, suggesting an increased reliance on lipids for energy while residing in the food-poor waters of the OMZ.

Cass, Christine J.; Daly, Kendra L.

2014-12-01

272

Prey selectivity and feeding periodicity of logperch larvae in Acton Lake, Ohio  

Microsoft Academic Search

Prey selectivity and feeding periodicity were determined from 263 gut analyses performed on logperchPercina caprodes larvae collected from Acton Lake during 26 May to 24 June 1983. Prey were observed only in larvae >7.4 mm total length. Larvae fed almost entirely on cladocerans and cyclopoid copepods; nauplii were conspicuously absent from the diet. Piscivory was observed in 9 larvae. Larvae

Lee A. Kissick

1987-01-01

273

Potential Predation by Fish and Invertebrates on Early Life History Stages of Striped Bass in the Pamunkey River, Virginia  

Microsoft Academic Search

Field surveys in the Pamunkey River, Virginia, indicated that numerous fish and invertebrate predators varied in their spatiotemporal coincidence with eggs and larvae of striped bass Morone saxatilis on spawning grounds. In the laboratory, the cyclopoid copepod Acanthocyclops vernalis was observed to attack and kill striped bass larvae, In addition, juveniles or adults of satinfin shiner Notropis analostanus, spottail shiner

John C. McGovern; John E. Olney

1988-01-01

274

Complex Deleterious Interactions Associated with Malic Enzyme May Contribute to Reproductive Isolation in the Copepod Tigriopus californicus  

PubMed Central

Dobzhansky-Muller incompatibilities can result from the interactions of more than a single pair of interacting genes and there are several different models of how such complex interactions can be structured. Previous empirical work has identified complex conspecific epistasis as a form of complex interaction that has contributed to postzygotic reproductive isolation between taxa, but other forms of complexity are also possible. Here, I probe the genetic basis of reproductive isolation in crosses of the intertidal copepod Tigriopus californicus by looking at the impact of markers in genes encoding metabolic enzymes in F2 hybrids. The region of the genome associated with the locus ME2 is shown to have strong, repeatable impacts on the fitness of hybrids in crosses and epistatic interactions with another chromosomal region marked by the GOT2 locus in one set of crosses. In a cross between one of these populations and a third population, these two regions do not appear to interact despite the continuation of a large effect of the ME2 region itself in both crosses. The combined results suggest that the ME2 chromosomal region is involved in incompatibilities with several unique partners. If these deleterious interactions all stem from the same factor in this region, that would suggest a different form of complexity from complex conspecific epistasis, namely, multiple independent deleterious interactions stemming from the same factor. Confirmation of this idea will require more fine-scale mapping of the interactions of the ME2 region of the genome. PMID:21731664

Willett, Christopher S.

2011-01-01

275

An H3-H4 histone gene pair in the marine copepod Tigriopus californicus, contains an intergenic dyad symmetry element.  

PubMed

Histone genes are one of the most widely studied multigene families in eucaryotes. Over 200 histone genes have been sequenced, primarily in vertebrates, echinoderms, fungi and plants. We present here the structure and genomic orientation of an H3-H4 histone gene pair from the marine copepod, Tigriopus californicus. These histone gene sequences are the first to be determined for the class Crustacea and among the first to be determined for protostomes. The H4 and H3 genes in Tigriopus are shown to be adjacent, to have opposite polarity, and to contain a 26 bp region of dyad symmetry centrally located within the spacer region between the two genes. A similarly located dyad element has been found in yeast which contributes to the coordinated cell cycle control of the adjacent histone genes. The Tigriopus H3-H4 histone gene pair is clustered with one H2A and two H2B histone genes on a 15 kb genomic Bam H1 fragment. The H4 gene sequence predicts an H4 protein with an unusual serine to threonine substitution at the amino terminal residue. The H3 gene sequence predicts an H3 protein which is identical to the vertebrate H3.2 histone. PMID:1840514

Porter, D; Brown, D; Wells, D

1991-01-01

276

Complex deleterious interactions associated with malic enzyme may contribute to reproductive isolation in the copepod Tigriopus californicus.  

PubMed

Dobzhansky-Muller incompatibilities can result from the interactions of more than a single pair of interacting genes and there are several different models of how such complex interactions can be structured. Previous empirical work has identified complex conspecific epistasis as a form of complex interaction that has contributed to postzygotic reproductive isolation between taxa, but other forms of complexity are also possible. Here, I probe the genetic basis of reproductive isolation in crosses of the intertidal copepod Tigriopus californicus by looking at the impact of markers in genes encoding metabolic enzymes in F(2) hybrids. The region of the genome associated with the locus ME2 is shown to have strong, repeatable impacts on the fitness of hybrids in crosses and epistatic interactions with another chromosomal region marked by the GOT2 locus in one set of crosses. In a cross between one of these populations and a third population, these two regions do not appear to interact despite the continuation of a large effect of the ME2 region itself in both crosses. The combined results suggest that the ME2 chromosomal region is involved in incompatibilities with several unique partners. If these deleterious interactions all stem from the same factor in this region, that would suggest a different form of complexity from complex conspecific epistasis, namely, multiple independent deleterious interactions stemming from the same factor. Confirmation of this idea will require more fine-scale mapping of the interactions of the ME2 region of the genome. PMID:21731664

Willett, Christopher S

2011-01-01

277

Nuclear and mitochondrial gene genealogies and allozyme polymorphism across a major phylogeographic break in the copepod Tigriopus californicus.  

PubMed

The genetic structure of natural populations is frequently inferred from geographic distributions of alleles at multiple gene loci. Surveys of allozyme polymorphisms in the tidepool copepod Tigriopus californicus have revealed sharp genetic differentiation of populations, indicating that gene flow among populations is highly restricted. Analysis of population structure in this species has now been extended to include nuclear and mitochondrial gene genealogies. DNA sequences of the mtDNA-encoded cytochrome-c oxidase subunit I gene from 21 isofemale lines derived from seven populations reveal a phylogeographic break between populations north and south of Point Conception, California, with sequence divergence across the break exceeding 18%, the highest level of mtDNA divergence yet reported among conspecific populations. Divergence between populations based on 22 sequences of the nuclear histone H1 gene is geographically concordant with the mitochondrial sequences. In contrast with previously studied nuclear genes in other sexually reproducing metazoans, the H1 gene genealogy from T. californicus shows no evidence of recombination. The apparent absence of intragenic recombinants probably results from the persistent lack of gene flow among geographically separated populations, a conclusion strongly supported by allozyme data and the mitochondrial gene genealogy. Despite strong population differentiation at allozyme loci, the phylogeographic break identified by the DNA sequences was not evident in the allozyme data. PMID:7910968

Burton, R S; Lee, B N

1994-05-24

278

Gamma radiation induces growth retardation, impaired egg production, and oxidative stress in the marine copepod Paracyclopina nana.  

PubMed

Accidental nuclear radioisotope release into the ocean from nuclear power plants is of concern due to ecological and health risks. In this study, we used the marine copepod Paracyclopina nana to examine the effects of radioisotopes on marine organisms upon gamma radiation, and to measure the effects on growth and fecundity, which affect population and community structure. Upon gamma radiation, mortality (LD50 - 96 h=172 Gy) in P. nana was significantly increased in a dose-dependent manner in ovigerous P. nana females. For developmental impairment of gamma-irradiated nauplii, we observed growth retardation; in over 30 Gy-irradiated groups, offspring did not grow to adults. Particularly, over 50 Gy-irradiated ovigerous P. nana females did not have normal bilateral egg sacs, and their offspring did not develop normally to adulthood. Additionally, at over 30 Gy, we found dose-dependent increases in oxidative levels with elevated antioxidant enzyme activities and DNA repair activities. These findings indicate that gamma radiation can induce oxidative stress and DNA damage with growth retardation and impaired reproduction. PMID:24632311

Won, Eun-Ji; Lee, Jae-Seong

2014-05-01

279

Multigenerational Exposure to Ocean Acidification during Food Limitation Reveals Consequences for Copepod Scope for Growth and Vital Rates.  

PubMed

The copepod Calanus finmarchicus is a key component of northern Atlantic food webs, linking energy-transfer from phytoplankton to higher trophic levels. We examined the effect of different ocean acidification (OA) scenarios (i.e., ambient, 1080, 2080, and 3080 ?atm CO2) over two subsequent generations under limited food availability. Determination of metabolic and feeding rates, and estimations of the scope for growth, suggests that negative effects observed on vital rates (ontogenetic development, somatic growth, fecundity) may be a consequence of energy budget constraints due to higher maintenance costs under high pCO2-environments. A significant delay in development rate among the parental generation animals exposed to 2080 ?atm CO2, but not in the following F1 generation under the same conditions, suggests that C. finmarchicus may have adaptive potential to withstand the direct long-term effects of even the more pessimistic future OA scenarios but underlines the importance of transgenerational experiments. The results also indicate that in a more acidic ocean, increased energy expenditure through rising respiration could lower the energy transfer to higher trophic levels and thus hamper the productivity of the northern Atlantic ecosystem. PMID:25225957

Pedersen, Sindre A; Håkedal, Ole Jacob; Salaberria, Iurgi; Tagliati, Alice; Gustavson, Liv Marie; Jenssen, Bjørn Munro; Olsen, Anders J; Altin, Dag

2014-10-21

280

Multi-decadal range changes vs. thermal adaptation for north east Atlantic oceanic copepods in the face of climate change.  

PubMed

Populations may potentially respond to climate change in various ways including moving to new areas or alternatively staying where they are and adapting as conditions shift. Traditional laboratory and mesocosm experiments last days to weeks and thus only give a limited picture of thermal adaptation, whereas ocean warming occurring over decades allows the potential for selection of new strains better adapted to warmer conditions. Evidence for adaptation in natural systems is equivocal. We used a 50-year time series comprising of 117 056 samples in the NE Atlantic, to quantify the abundance and distribution of two particularly important and abundant members of the ocean plankton (copepods of the genus Calanus) that play a key trophic role for fisheries. Abundance of C. finmarchicus, a cold-water species, and C. helgolandicus, a warm-water species, were negatively and positively related to sea surface temperature (SST) respectively. However, the abundance vs. SST relationships for neither species changed over time in a manner consistent with thermal adaptation. Accompanying the lack of evidence for thermal adaptation there has been an unabated range contraction for C. finmarchicus and range expansion for C. helgolandicus. Our evidence suggests that thermal adaptation has not mitigated the impacts of ocean warming for dramatic range changes of these key species and points to continued dramatic climate induced changes in the biology of the oceans. PMID:24323534

Hinder, Stephanie L; Gravenor, Mike B; Edwards, Martin; Ostle, Clare; Bodger, Owen G; Lee, Patricia L M; Walne, Antony W; Hays, Graeme C

2014-01-01

281

Multilocus evidence for globally distributed cryptic species and distinct populations across ocean gyres in a mesopelagic copepod.  

PubMed

Zooplanktonic taxa have a greater number of distinct populations and species than might be predicted based on their large population sizes and open-ocean habitat, which lacks obvious physical barriers to dispersal and gene flow. To gain insight into the evolutionary mechanisms driving genetic diversification in zooplankton, we developed eight microsatellite markers to examine the population structure of an abundant, globally distributed mesopelagic copepod, Haloptilus longicornis, at 18 sample sites across the Atlantic and Pacific Oceans (n = 761). When comparing our microsatellite results with those of a prior study that used a mtDNA marker (mtCOII, n = 1059, 43 sample sites), we unexpectedly found evidence for the presence of a cryptic species pair. These species were globally distributed and apparently sympatric, and were separated by relatively weak genetic divergence (reciprocally monophyletic mtCOII lineages 1.6% divergent; microsatellite FST ranging from 0.28 to 0.88 across loci, P < 0.00001). Using both mtDNA and microsatellite data for the most common of the two species (n = 669 for microsatellites, n = 572 for mtDNA), we also found evidence for allopatric barriers to gene flow within species, with distinct populations separated by continental landmasses and equatorial waters in both the Atlantic and Pacific Ocean basins. Our study shows that oceanic barriers to gene flow can act as a mechanism promoting allopatric diversification in holoplanktonic taxa, despite the high potential dispersal abilities and pelagic habitat for these species. PMID:25283587

Andrews, Kimberly R; Norton, Emily L; Fernandez-Silva, Iria; Portner, Elan; Goetze, Erica

2014-11-01

282

Spatio-temporal variability of copepod abundance along the 20 °S monitoring transect in the Northern Benguela upwelling system from 2005 to 2011.  

PubMed

Long-term data sets are essential to understand climate-induced variability in marine ecosystems. This study provides the first comprehensive analysis of longer-term temporal and spatial variations in zooplankton abundance and copepod community structure in the northern Benguela upwelling system from 2005 to 2011. Samples were collected from the upper 200 m along a transect at 20 °S perpendicular to the coast of Namibia to 70 nm offshore. Based on seasonal and interannual trends in surface temperature and salinity, three distinct time periods were discernible with stronger upwelling in spring and extensive warm-water intrusions in late summer, thus, high temperature amplitudes, in the years 2005/06 and 2010/11, and less intensive upwelling followed by weaker warm-water intrusions from 2008/09 to 2009/10. Zooplankton abundance reflected these changes with higher numbers in 2005/06 and 2010/11. In contrast, zooplankton density was lower in 2008/09 and 2009/10, when temperature gradients from spring to late summer were less pronounced. Spatially, copepod abundance tended to be highest between 30 and 60 nautical miles off the coast, coinciding with the shelf break and continental slope. The dominant larger calanoid copepods were Calanoides carinatus, Metridia lucens and Nannocalanus minor. On all three scales studied, i.e. spatially from the coast to offshore waters as well as temporally, both seasonally and interannually, maximum zooplankton abundance was not coupled to the coldest temperature regime, and hence strongest upwelling intensity. Pronounced temperature amplitudes, and therefore strong gradients within a year, were apparently important and resulted in higher zooplankton abundance. PMID:24844305

Bode, Maya; Kreiner, Anja; van der Plas, Anja K; Louw, Deon C; Horaeb, Richard; Auel, Holger; Hagen, Wilhelm

2014-01-01

283

Spatio-Temporal Variability of Copepod Abundance along the 20?S Monitoring Transect in the Northern Benguela Upwelling System from 2005 to 2011  

PubMed Central

Long-term data sets are essential to understand climate-induced variability in marine ecosystems. This study provides the first comprehensive analysis of longer-term temporal and spatial variations in zooplankton abundance and copepod community structure in the northern Benguela upwelling system from 2005 to 2011. Samples were collected from the upper 200 m along a transect at 20°S perpendicular to the coast of Namibia to 70 nm offshore. Based on seasonal and interannual trends in surface temperature and salinity, three distinct time periods were discernible with stronger upwelling in spring and extensive warm-water intrusions in late summer, thus, high temperature amplitudes, in the years 2005/06 and 2010/11, and less intensive upwelling followed by weaker warm-water intrusions from 2008/09 to 2009/10. Zooplankton abundance reflected these changes with higher numbers in 2005/06 and 2010/11. In contrast, zooplankton density was lower in 2008/09 and 2009/10, when temperature gradients from spring to late summer were less pronounced. Spatially, copepod abundance tended to be highest between 30 and 60 nautical miles off the coast, coinciding with the shelf break and continental slope. The dominant larger calanoid copepods were Calanoides carinatus, Metridia lucens and Nannocalanus minor. On all three scales studied, i.e. spatially from the coast to offshore waters as well as temporally, both seasonally and interannually, maximum zooplankton abundance was not coupled to the coldest temperature regime, and hence strongest upwelling intensity. Pronounced temperature amplitudes, and therefore strong gradients within a year, were apparently important and resulted in higher zooplankton abundance. PMID:24844305

Bode, Maya; Kreiner, Anja; van der Plas, Anja K.; Louw, Deon C.; Horaeb, Richard; Auel, Holger; Hagen, Wilhelm

2014-01-01

284

Community structure and estimated contribution of primary consumers (Nematodes and Copepods) of decomposing plant litter (Juncus roemerianus and Rhizophora mangle) in South Florida  

SciTech Connect

The paper discusses the meiofauna associated with decomposing leaf litter from two species of coastal marshland plants: the black needle rush, Juncus roemerianus and the red mangrove, Rhizophora mangle. The following aspects were investigated: (1) types of meiofauna present, especially nematodes; (2) changes in meiofaunal community structures with regard to season, station location, and type of plant litter; (3) amount of nematode and copepod biomass present on the decomposing plant litter; and (4) an estimation of the possible role of the nematodes in the decomposition process. 28 references, 5 figures, 9 tables. (ACR)

Fell, J.W.; Cefalu, R.

1984-01-01

285

Genomic Characterization and Phylogenetic Position of Two New Species in Rhabdoviridae Infecting the Parasitic Copepod, Salmon Louse (Lepeophtheirus salmonis)  

PubMed Central

Several new viruses have emerged during farming of salmonids in the North Atlantic causing large losses to the industry. Still the blood feeding copepod parasite, Lepeophtheirus salmonis, remains the major challenge for the industry. Histological examinations of this parasite have revealed the presence of several virus-like particles including some with morphologies similar to rhabdoviruses. This study is the first description of the genome and target tissues of two new species of rhabdoviruses associated with pathology in the salmon louse. Salmon lice were collected at different Atlantic salmon (Salmo salar) farming sites on the west coast of Norway and prepared for histology, transmission electron microscopy and Illumina sequencing of the complete RNA extracted from these lice. The nearly complete genomes, around 11 600 nucleotides encoding the five typical rhabdovirus genes N, P, M, G and L, of two new species were obtained. The genome sequences, the putative protein sequences, and predicted transcription strategies for the two viruses are presented. Phylogenetic analyses of the putative N and L proteins indicated closest similarity to the Sigmavirus/Dimarhabdoviruses cluster, however, the genomes of both new viruses are significantly diverged with no close affinity to any of the existing rhabdovirus genera. In situ hybridization, targeting the N protein genes, showed that the viruses were present in the same glandular tissues as the observed rhabdovirus-like particles. Both viruses were present in all developmental stages of the salmon louse, and associated with necrosis of glandular tissues in adult lice. As the two viruses were present in eggs and free-living planktonic stages of the salmon louse vertical, transmission of the viruses are suggested. The tissues of the lice host, Atlantic salmon, with the exception of skin at the attachment site for the salmon louse chalimi stages, were negative for these two viruses. PMID:25402203

Økland, Arnfinn Lodden; Nylund, Are; Øvergård, Aina-Cathrine; Blindheim, Steffen; Watanabe, Kuninori; Grotmol, Sindre; Arnesen, Carl-Erik; Plarre, Heidrun

2014-01-01

286

Molecular evolution at the cytochrome oxidase subunit 2 gene among divergent populations of the intertidal copepod, Tigriopus californicus.  

PubMed

The cytochrome c oxidase subunit 2 gene (COII) encodes a highly conserved protein that is directly responsible for the initial transfer of electrons from cytochrome c to cytochrome c oxidase (COX) crucial to the production of ATP during cellular respiration. Despite its integral role in electron transport, we have observed extensive intraspecific nucleotide and amino acid variation among 26 full-length COII sequences sampled from seven populations of the marine copepod, Tigriopus californicus. Although intrapopulation divergence was virtually nonexistent, interpopulation divergence at the COII locus was nearly 20% at the nucleotide level, including 38 nonsynonymous substitutions. Given the high degree of interaction between the cytochrome c oxidase subunit 2 protein (COX2) and the nuclear-encoded subunits of COX and cytochrome c (CYC), we hypothesized that some codons in the COII gene are likely to be under positive selection in order to compensate for amino acid substitutions in other subunits. Estimates of the ratio of nonsynonymous to synonymous substitution (omega), obtained using a series of maximum likelihood models of codon substitution, indicated that the majority of codons in T. californicus COII are under strong purifying selection (omega < 1), while approximately 4% of the sites in this gene appear to evolve under relaxed selective constraint (omega = 1). A branch-site maximum likelihood model identified three sites that may have experienced positive selection within the central California sequence clade in our COII phylogeny; these results are consistent with previous studies showing functional and fitness consequences among interpopulation hybrids between central and northern California populations. PMID:16752213

Rawson, Paul D; Burton, Ronald S

2006-06-01

287

Genomic Characterization and Phylogenetic Position of Two New Species in Rhabdoviridae Infecting the Parasitic Copepod, Salmon Louse (Lepeophtheirus salmonis).  

PubMed

Several new viruses have emerged during farming of salmonids in the North Atlantic causing large losses to the industry. Still the blood feeding copepod parasite, Lepeophtheirus salmonis, remains the major challenge for the industry. Histological examinations of this parasite have revealed the presence of several virus-like particles including some with morphologies similar to rhabdoviruses. This study is the first description of the genome and target tissues of two new species of rhabdoviruses associated with pathology in the salmon louse. Salmon lice were collected at different Atlantic salmon (Salmo salar) farming sites on the west coast of Norway and prepared for histology, transmission electron microscopy and Illumina sequencing of the complete RNA extracted from these lice. The nearly complete genomes, around 11 600 nucleotides encoding the five typical rhabdovirus genes N, P, M, G and L, of two new species were obtained. The genome sequences, the putative protein sequences, and predicted transcription strategies for the two viruses are presented. Phylogenetic analyses of the putative N and L proteins indicated closest similarity to the Sigmavirus/Dimarhabdoviruses cluster, however, the genomes of both new viruses are significantly diverged with no close affinity to any of the existing rhabdovirus genera. In situ hybridization, targeting the N protein genes, showed that the viruses were present in the same glandular tissues as the observed rhabdovirus-like particles. Both viruses were present in all developmental stages of the salmon louse, and associated with necrosis of glandular tissues in adult lice. As the two viruses were present in eggs and free-living planktonic stages of the salmon louse vertical, transmission of the viruses are suggested. The tissues of the lice host, Atlantic salmon, with the exception of skin at the attachment site for the salmon louse chalimi stages, were negative for these two viruses. PMID:25402203

Okland, Arnfinn Lodden; Nylund, Are; Overgård, Aina-Cathrine; Blindheim, Steffen; Watanabe, Kuninori; Grotmol, Sindre; Arnesen, Carl-Erik; Plarre, Heidrun

2014-01-01

288

Sensitivity of Calanus spp. copepods to environmental changes in the North Sea using life-stage structured models  

NASA Astrophysics Data System (ADS)

The copepods Calanus finmarchicus and Calanus helgolandicus co-exist in the North Sea, but their spatial distribution and phenology are very different. Long-term changes in their distributions seem to occur due to climate change resulting in a northward extension of C. helgolandicus and a decline of C. finmarchicus in this region. The aim of this study is to use life-stage structured models of the two Calanus species embedded in a 3D coupled hydrodynamic-biogeochemical model to investigate how the biogeography of C. finmarchicus and C. helgolandicus is modified by changes in ±2 °C sea water temperatures, overwintering and oceanic inflow in the North Sea. Life-stage structured models are validated against CPR data and vertical distributions north of the Dogger Bank in the North Sea for the reference year 2005. The model shows that (1) ±2 °C changes from the current level mainly influence the seasonal patterns and not the relative occurrence of the two species, (2) changes due to oceanic inflow mainly appeared in the northern and southern part of the North Sea connected to the NE Atlantic and not in the central part and (3) the abundance of Calanus species were very sensitive to the degree of overwintering within the North Sea because it allows them to utilise the spring bloom more efficiently and independently of the timing and amount of oceanic inflow. The combination of lower temperatures, higher overwintering and oceanic inflow simulating the situation in the 1960s largely favoured C. finmarchicus and their relative contribution to Calanus spp. increased from 40% in the reference year to 72%. The +2 °C scenario suggest that in a warmer future, C. finmarchicus is likely to decline and C. helgolandicus abundance will probably continue to increase in some areas.

Maar, Marie; Møller, Eva Friis; Gürkan, Zeren; Jónasdóttir, Sigrún H.; Nielsen, Torkel Gissel

2013-04-01

289

Long-term decline in the calanoid copepod Acartia tonsa in central Chesapeake Bay, USA: An indirect effect of eutrophication?  

NASA Astrophysics Data System (ADS)

A long-term abundance record of the calanoid copepod Acartia tonsa in the Maryland portion of Chesapeake Bay was compiled from 1966 to 2002. A significant downward trend in the summertime abundance of Acartia tonsa was found in central Chesapeake Bay. We propose that environmental and food web changes occurred as the Chesapeake Bay became increasingly impacted by human activity which eventually led to the overall decline of A. tonsa. Environmental changes included a long-term rise in water temperature and the volume of hypoxic water during the summer. These changes occurred during the same time period as increases in chlorophyll a concentration, declines in the landings of the eastern oyster Crassostrea virginica, and declines in abundance of the sea nettle Chrysaora quinquecirrha. A CUSUM analysis showed that each time-series experienced a change point during over the past 50 years. These changes occurred sequentially, with chlorophyll a concentration increasing beginning in 1969, water temperature and hypoxic volume increasing beginning in the early 1980s, more recent Maryland C. virginica landings begin declining in the early 1980s and A. tonsa and C. quinquecirrha declining starting in 1989. A stepwise regression analysis revealed that the reduction in A. tonsa abundance appeared to be most associated with a decreasing trend in C. quinquecirrha abundance, though only when trends in the two time-series were present. The drop in C. quinquecirrha abundance is associated with reduced predation on the ctenophore, Mnemiopsis leidyi, a key predator of A. tonsa. The long-term decline of A. tonsa has likely impacted trophic transfer to fish, particularly the zooplanktivorous bay anchovy (Anchoa mitchilli). A time-series of bay anchovy juvenile index showed a negative trend and the CUSUM analysis revealed 1993 as its starting point. Total fisheries landings, excluding menhaden (Brevoortia tyrannus), in Chesapeake Bay have also declined during the same period and this also began in 1993, further suggesting a potential fisheries impact from the decline in A. tonsa abundance.

Kimmel, David G.; Boynton, Walter R.; Roman, Michael R.

2012-04-01

290

Dissimilarity of Species and Forms of Planktonic Neocalanus Copepods Using Mitochondrial COI, 12S, Nuclear ITS, and 28S Gene Sequences  

PubMed Central

Background A total of six Neocalanus species inhabit the oceans of the world. Of these, three species plus form variants (N. cristatus, N. plumchrus, N. flemingeri large form, and N. flemingeri small form), which constitute a monophyletic group among Neocalanus copepods, occur in the Northwestern Pacific off Japan. In the present study, we have tried to discriminate the three species plus form variants of Neocalanus copepods based on sequences of four DNA marker regions. Methodology/Principal Findings Discrimination was performed based on the DNA sequence information from four genetic markers, including the mitochondrial COI, 12S, nuclear ITS, and 28S gene regions. Sequence dissimilarity was compared using both distance- and character-based approaches. As a result, all three species were confirmed to be distinct based on the four genetic marker regions. On the contrary, distinction of the form variants was only confirmed based on DNA sequence of the mitochondrial COI gene region. Conclusions/Significance Although discrimination was not successful for the form variants based on the mitochondrial 12S, nuclear ITS, and 28S genes, diagnostic nucleotide sequence characters were observed in their mitochondrial COI gene sequences. Therefore, these form variants are considered to be an important unit of evolution below the species level, and constitute a part of the Neocalanus biodiversity. PMID:20442767

Machida, Ryuji J.; Tsuda, Atsushi

2010-01-01

291

Variability in the egg production rates of the calanoid copepod, Pseudodiaptomus hessei in a South African estuary in relation to environmental factors  

NASA Astrophysics Data System (ADS)

The importance of physical parameters (temperature and salinity) and seston composition (chlorophyll a, protein, carbohydrate and lipid concentration as well as fatty acid composition) in controlling the in situ egg productions rate (EPR) of the calanoid copepod, Pseudodiaptomus hessei, was investigated monthly in a permanently open South African estuary over a one year period. The EPR of P. hessei ranged from 3.00 to 37.23 eggs F-1 d-1 and were amongst the highest rates published for egg-carrying copepods. EPR varied significantly between months while hatching success was constant and high throughout the study period (91% on average). A stepwise multiple linear regression selected temperature - Chl a 2-20 ?m size fraction and temperature - 16:1(n-7) as the best descriptors of EPR (R2 = 0.86) and nauplii production (R2 = 0.92), respectively. The maximum values of EPR were recorded in September and December, following freshwater inflow into the estuary. September had an extremely high level of Chl a while December showed only an average level. We suggest that the EPR of P. hessei is also influenced by indirect effect of freshwater input into the estuary. The freshwater input modified the nutrient concentration and composition and as such altered the fatty acid seston composition which enhanced the EPR.

Noyon, Margaux; William Froneman, P.

2013-12-01

292

Assessing the In Situ Fertilization Status of Two Marine Copepod Species, Temora longicornis and Eurytemora herdmani; How Common Are Unfertilized Eggs in Nature?  

PubMed Central

We utilized an egg staining technique to measure the in situ fertilization success of two marine copepod species, Temora longicornis and Eurytemora herdmani from May to October 2008 in coastal Maine and correlated fertilization success with environmental conditions in their habitat. T. longicornis is a free spawning species that releases eggs into the ambient seawater after mating. In contrast, E. herdmani carries eggs in an egg sac until they hatch. The proportion of fertilized eggs within E. herdmani egg sacs was significantly higher than the freely spawned clutches of T. longicornis. This may be a result of the asymmetrical costs associated with carrying vs. spawning unfertilized eggs. T. longicornis frequently laid both fertilized and unfertilized eggs within their clutch. T. longicornis fertilization was negatively associated with chlorophyll concentration and positively associated with population density in their local habitat. The fertilization status of E. herdmani egg sacs was high throughout the season, but the proportion of ovigerous females was negatively associated with an interaction between predators and the proportion of females in the population. This study emphasizes that, in addition to population level processes, community and ecosystem level processes strongly influence the fertilization success and subsequent productivity of copepods. PMID:25397669

Lasley-Rasher, Rachel S.; Kramer, Andrew M.; Burdett-Coutts, Victoria; Yen, Jeannette

2014-01-01

293

Seasonal variability of community structure and breeding activity in marine phytal harpacticoid copepods on Ulva pertusa from Pohang, east coast of Korea  

NASA Astrophysics Data System (ADS)

Seasonal changes in community structure and reproductive status of phytal harpacticoid copepods in the shallow sublittoral bottom at two sites (Masan-ri and Guryongpo) in Pohang (Korea) are described monthly over a period of 1 year (October 1996 to September 1997). A total of 36 harpacticoid species was identified and the numerically dominant copepods were made up of the families Porcellidiidae and Tisbidae. Although the number of species did not show a seasonal trend, total harpacticoid density revealed a favorable distribution for the warmer season (spring and summer) at both sites. Multiple linear regression analyses showed that univariate indices such as density, evenness and diversity are closely associated with certain environmental parameters. For example, the dominant species fluctuated seasonally in abundance and their maximum densities were found to be temperature- (+ with Porcellidium ofunatense) and nutrient-dependent (+ with Scutellidium longicauda acheloides, + with Zaus unisetosus, and - with P. wandoensis). In addition, the dominant species appeared to breed year round and their reproductive indices are significantly correlated with some environmental parameters such as temperature (-), pH (+), and phosphate (+). Three species ( S. l. acheloides, P. wandoensis, and P. ofunatense) showed maximum density two or three months after their reproductive activity reached a maximum. Overall, the seasonal changes in a phytal harpacticoid community could be explained by combinations of environmental parameters supporting the complexity and biodiversity for this specific group of species in coastal ecosystems.

Song, Sung Joon; Ryu, Jongseong; Khim, Jong Seong; Kim, Won; Yun, Sung Gyu

2010-01-01

294

Spatial and seasonal variations in size, body volume and body proportion (prosome:urosome ratio) of the copepod Acartia tonsa in a semi-closed ecosystem (Berre lagoon, western Mediterranean)  

Microsoft Academic Search

Variations in size (prosome), body volume and proportion (prosome:urosome ratio) of female Acartia tonsa copepods were studied during three different seasons (June, October and November) in a network of 13 stations distributed throughout the Berre Lagoon, near Marseille. Strong morphological differences were found between the populations collected through the different seasonal surveys, but also between the different stations or groups

R. Gaudy; G. Verriopoulos

2004-01-01

295

Body mass and lipid dynamics of Arctic and Antarctic deep-sea copepods (Calanoida, Paraeuchaeta): ontogenetic and seasonal trends  

NASA Astrophysics Data System (ADS)

Ontogenetic and seasonal trends in body dry mass (DM) and total lipid content were studied in polar species of the predatory calanoid copepod genus Paraeuchaeta. Analyses included the Arctic representatives Paraeuchaeta glacialis, P. norvegica, P. barbata, and P. polaris as well as the Antarctic congener P. antarctica and one sample of P. cf. biloba. A total of 567 samples including 7007 individuals collected during four Antarctic and six Arctic research cruises was processed to provide seasonal coverage from spring to fall for both areas investigated, the Antarctic Weddell Sea and Arctic Fram Strait. All epipelagic species, i.e. P. glacialis, P. norvegica, and P. antarctica, showed a continuous increase in body DM from early copepodite stage CI onwards to stage CV. On average, body mass tripled with every moult. In females, body mass tripled again during the last moult to adulthood, whereas adult males, which have reduced mouthparts and do not feed at all, did not significantly increase their body mass after moulting from the CV stage. In contrast, early stages, i.e. nauplii to copepodids CII, of the bathypelagic species P. barbata remained at similar DMs. The deepest living species P. polaris was characterised by relatively large juvenile stages but small adult females, resulting in a rather small increase in body mass during ontogenetic development. Total lipid content decreased from maximum values of 60-70% of DM in eggs and early copepodite stages to <20-30% DM in stage CIII. Starting with stage CIV, lipids were again accumulated leading to high values of 40% to >50% DM in adult females. Distinct differences were detected with regard to seasonal trends of body mass and lipid content between epipelagic and bathypelagic species: Copepodids CIV, CV and adult females of epipelagic species exhibited highest body masses and lipid contents in fall, whereas for the deeper-living P. barbata maximum values occurred in spring. These discrepancies are discussed in relation to reproductive patterns and differences in abiotic and biotic environmental factors between the epipelagic and bathypelagic zones.

Auel, Holger; Hagen, Wilhelm

2005-07-01

296

Grazing in tropical copepods, measured by gut fluorescence, in relation to seasonal upwelling in the Banda Sea (Indonesia)  

NASA Astrophysics Data System (ADS)

The amount of chlorophyll pigments in the gut was measured fluorometrically in adult females of 27 species of copepods sampled in the eastern Banda Sea during the Indonesian-Dutch Snellius-II Expedition. During the southeast monsoon (August 1984) and the northwest monsoon (February-March 1985) vertical net hauls were made near a subsurface drifter at four stations, covering several day and night periods and the depth strata 0 to 50, 50 to 150 and 150 to 250 m, with 250 to 500 m added at some stations. Diurnal feeding rhythms were frequently observed. At all stations, significantly higher values of gut fluorescence occurred at night in about 60% of the species, except for 22% at the August station in the Aru Basin, where upwelling was clearest. Reverse rhythms were not detected. Intraspecific differences reflected the vertical heterogeniety between stations: at the upwelling site 67% of the species had higher fluorescence levels in the upper 50 m; at the oligotrophic February stations, with a deep chlorophyll maximum at 50 to 70 m, this was only 5%. In many species the increase in gut fluorescence by night was not limited to the upper layer but extended to 150 to 250 m, which suggests rapid sinking of satiated animals. Carbon body weights were measured to determine the weight-specific gut fluorescence. This was at a maximum at the upwelling station, and there highest in Eucalanus and Temora, and only moderate in the upwelling species Calanoides. At the other stations no clear differences in weight-specific gut fluorescence occurred between species differing in feeding behaviour. In Cosmocalanus, Undinula, Euchaeta and Candacia the carbon weight of adult females was twice as high in the upwelling season as in the other season. Daily rations, estimated using a mean gut passage time of 30 min, were on average only 11% of body carbon. But at the upwelling station about 70%. Estimates of daily mesozooplankton grazing varied between 2 and 6% of the standing stock of chlorophyll, and between 5 and 26% of the primary production. Highest figures concern the upwelling site, where ambient HPLC-determined phaeophorbide concentrations were also at a maximum.

Arinardi, O. H.; Baars, M. A.; Oosterhuis, S. S.

297

Feeding ecology of the copepod Lucicutia aff. L. grandis near the lower interface of the Arabian Sea oxygen minimum zone  

NASA Astrophysics Data System (ADS)

Feeding ecology of the calanoid copepod Lucicutia aff. L. grandis collected in the Arabian Sea at one station during the Spring Intermonsoon and during the Southwest Monsoon of 1995 was studied with transmission electron microscopy of gut-contents. Highest abundances of these animals occurred from ˜400 to 1100 m, near the lower interface of the oxygen minimum zone and at the inflection point where oxygen starts to increase. We expected that their gut-contents would include particles and cells that had sunk relatively undegraded from surface waters as well as those from within the oxygen minimum zone, and that gut-contents would differ between the Spring Intermonsoon and the more productive SW Monsoon. Overall, in both seasons Lucicutia aff. L. grandis was omnivorous, and consumed a variety of detrital particles, prokaryotic and eukaryotic autotrophs, gram-negative bacteria including metal-precipitating bacteria, aggregates of probable gram-positive bacteria, microheterotrophs, virus-like particles and large virus-like particles, as well as cuticle and cnidarian tissue. Few significant differences in types of food consumed were seen among life stages within or among various depth zones. Amorphous, unidentifiable material was significantly more abundant in guts during the Spring Intermonsoon than during the late SW Monsoon, and recognizable cells made up a significantly higher portion of gut-contents during the late SW Monsoon. This is consistent with the Intermonsoon as a time when organic material is considerably re-worked by the surface water microbial loop before leaving the euphotic zone. In both seasons Lucicutia aff. L. grandis had consumed what appeared to be aggregates of probable gram-positive bacteria, similar to those we had previously found in gut-contents of several species of zooplankton from the oxygen minimum zone in the eastern tropical Pacific. By intercepting sinking material, populations of Lucicutia aff. L. grandis act as a filter for carbon sinking to the sea floor. They also modify sinking carbon in several ways: enhancing pelagic-abyssal coupling of carbon from cyanobacteria, eliminating part of the deep-sea microbial loop by direct consumption of bacterial aggregates, and redistributing particulate manganese and iron from association with suspended cells or aggregates to containment in rapidly sinking fecal pellets. Lucicutia aff. L. grandis can be viewed as representative of deep-dwelling detritivorous mesozooplankton. Assessing the magnitude of the effects of such organisms on carbon flux in the Arabian Sea will require data on feeding rates.

Gowing, Marcia M.; Wishner, Karen F.

298

Basin-scale population genetic structure of the planktonic copepod Calanus finmarchicus in the North Atlantic Ocean  

NASA Astrophysics Data System (ADS)

Pelagic marine invertebrates have extensive potential for gene flow, although barriers to gene flow and entrainment in ocean currents may lead to reproductive isolation or drift, and thus to genetic differentiation of populations. The planktonic calanoid copepod Calanus finmarchicus shows significant geographic variation in life history traits across subarctic zones of the N. Atlantic Ocean. Population genetic analysis of C. finmarchicus examined allelic variation at 24 single nucleotide polymorphic (SNP) sites in three nuclear protein-coding genes: citrate synthase, heat-shock protein-70, and AMP-activated protein kinase. Samples were collected during 2005 from 10 areas representing the Northwest (NW), North Central (NC), and Northeast (NE) Atlantic gyres. Hypotheses of two or more distinct populations of C. finmarchicus were examined based on SNP variation within the three genes analyzed both separately and together using AMOVA ( Arlequin Ver. 3.11), CLUMPP (Ver. 1.1), GENALEX (Ver. 6.2), Genepop (Ver. 4.0.10), and Structure (Ver. 2.3). All analyses revealed evidence of small but significant differentiation among areas within gyres (e.g., FSC = 0.0306, p < 0.0001 for two populations; FSC = 0.0344, p < 0.0001 for three populations; pairwise FST values for all 10 areas ranged from 0.0000 to 0.2400), which may reflect ecologically-important, short-term (on the order of months) variation driven by geographic variation in life history traits. Support for underlying large-scale differentiation, which may reflect persistent barriers to gene flow associated with entrainment in ocean gyres, was provided by various analyses, with numbers of distinct C. finmarchicus populations ranging from two to four. Analysis of molecular variation supported two populations, while clustering and population assignment supported two, three, or four populations. The Barents Sea sample was especially distinctive: one test using AMOVA was non-significant among gyres without this sample and differentiation among area populations within gyres was reduced. Analysis of additional genes, higher resolution sampling, and comparisons across different years are needed to resolve the spatial limits and number of distinct C. finmarchicus populations across the N. Atlantic Ocean basin.

Unal, Ebru; Bucklin, Ann

2010-10-01

299

Feeding ecology of pelagic larval Burbot in Northern Lake Huron, Michigan  

USGS Publications Warehouse

Burbot Lota lota are a key demersal piscivore across the Laurentian Great Lakes whose populations have declined by about 90% in recent decades. Larval Burbot typically hatch in the early spring and rely on abundant crustacean zooplankton prey. We examined the stomach contents of larval Burbot from inshore (?15 m) and offshore sites (37 and 91 m) in northern Lake Huron, Michigan. Concurrent zooplankton vertical tows at the same sites showed that the prey community was dominated by calanoid copepods, dreissenid mussel veligers, and rotifers. Burbot consumed mostly cyclopoid copepods, followed by copepod nauplii and calanoid copepods. Chesson's index of selectivity was calculated and compared among sites and months for individual Burbot. According to this index, larval Burbot exhibited positive selection for cyclopoid copepods and copepod nauplii and negative selection for calanoid copepods, cladocerans, rotifers, and dreissenid veligers. This selectivity was consistent across sites and throughout the sampling period. Burbot displayed little variation in their prey preferences during the larval stage, which suggests that the recent shifts in zooplankton abundance due to the invasion of the predatory zooplankter Bythotrephes longimanus and competition from invasive Rainbow Smelt Osmerus mordax could negatively impact larval Burbot populations.

George, Ellen M.; Roseman, Edward F.; Davis, Bruce M.; O'Brien, Timothy P.

2013-01-01

300

Bathymetric patterns of ? and ? diversity of harpacticoid copepods at the genus level around the Ryukyu Trench, and turnover diversity between trenches around Japan  

NASA Astrophysics Data System (ADS)

The diversity of harpacticoid copepods was investigated around the Ryukyu Trench (430-7150 m), which lies below an oligotrophic subtropical ocean. The ? diversity, which is based on the number of genera and Shannon diversity decreased with increasing water depth. The community structure of harpacticoids gradually changed as the water depth increased from the bathyal zone to the hadal zone. Turnover (?) diversity values were equally high between the trench slope, trench floor and abyssal plain. We compared the harpacticoid assemblage obtained from the Ryukyu region with the assemblage from a region around the Kuril Trench (Kitahashi et al., 2013). Turnover diversity values between the two regions (? diversity) were relatively low at shallow depths, but they increased with increasing water depth and reached their maximum between the trench floors and abyssal plains. These findings indicate that the bathymetric patterns of harpacticoid assemblages differ among regions and that these discrepancies reflect differences in environmental conditions, such as primary productivity level.

Kitahashi, Tomo; Kawamura, Kiichiro; Kojima, Shigeaki; Shimanaga, Motohiro

2014-04-01

301

Seasonal occurrence and microhabitat of the hyperparasitic monogenean Udonella fugu on the caligid Copepod Pseudocaligus fugu infecting the grass puffer Takifugu niphobles in the Seto Inland Sea, Japan  

NASA Astrophysics Data System (ADS)

The seasonal occurrence and microhabitat of the monogenean Udonella fugu that hyperparasitizes exclusively on adults of the caligid copepod Pseudocaligus fugu that infects the skin of the grass puffer Takifugu niphobles were investigated in the Seto Inland Sea, western Japan from November 2004 to December 2006. The udonellids occurred and bred mostly during the occurrence of P. fugu on the fish host. The average prevalence and intensity of U. fugu on P. fugu during the whole investigation were 29% and 3.6, respectively. The main attachment sites of U. fugu were the posterior side of leg 3 and the dorsal marginal side of the cephalothorax for feeding and copulation, while eggs were predominantly located on the ventral side of the urosome to avoid detachment. More attention should be paid to the ecology of U. fugu, due to recent high prevalence of P. fugu on cultured tiger puffer in western Japan.

Okawachi, Hiroko; Ohtsuka, Susumu; Ismail, Norshida Binti; Venmathi Maran, B. A.; Ogawa, Kazuo

2012-09-01

302

Investigating the molecular basis of local adaptation to thermal stress: population differences in gene expression across the transcriptome of the copepod Tigriopus californicus  

PubMed Central

Background Geographic variation in the thermal environment impacts a broad range of biochemical and physiological processes and can be a major selective force leading to local population adaptation. In the intertidal copepod Tigriopus californicus, populations along the coast of California show differences in thermal tolerance that are consistent with adaptation, i.e., southern populations withstand thermal stresses that are lethal to northern populations. To understand the genetic basis of these physiological differences, we use an RNA-seq approach to compare genome-wide patterns of gene expression in two populations known to differ in thermal tolerance. Results Observed differences in gene expression between the southern (San Diego) and the northern (Santa Cruz) populations included both the number of affected loci as well as the identity of these loci. However, the most pronounced differences concerned the amplitude of up-regulation of genes producing heat shock proteins (Hsps) and genes involved in ubiquitination and proteolysis. Among the hsp genes, orthologous pairs show markedly different thermal responses as the amplitude of hsp response was greatly elevated in the San Diego population, most notably in members of the hsp70 gene family. There was no evidence of accelerated evolution at the sequence level for hsp genes. Among other sets of genes, cuticle genes were up-regulated in SD but down-regulated in SC, and mitochondrial genes were down-regulated in both populations. Conclusions Marked changes in gene expression were observed in response to acute sub-lethal thermal stress in the copepod T. californicus. Although some qualitative differences were observed between populations, the most pronounced differences involved the magnitude of induction of numerous hsp and ubiquitin genes. These differences in gene expression suggest that evolutionary divergence in the regulatory pathway(s) involved in acute temperature stress may offer at least a partial explanation of population differences in thermal tolerance observed in Tigriopus. PMID:22950661

2012-01-01

303

Crude oil exposure results in oxidative stress-mediated dysfunctional development and reproduction in the copepod Tigriopus japonicus and modulates expression of cytochrome P450 (CYP) genes.  

PubMed

In this study, we investigated the effects of the water-accommodated fraction (WAF) of crude oil on the development and reproduction of the intertidal copepod Tigriopus japonicus through life-cycle experiments. Furthermore, we investigated the mechanisms underlying the toxic effects of WAF on this benthic organism by studying expression patterns of cytochrome P450 (CYP) genes. Development of T. japonicus was delayed and molting was interrupted in response to WAF exposure. Hatching rate was also significantly reduced in response to WAF exposure. Activities of antioxidant enzymes such as glutathione S-transferase (GST), glutathione reductase (GR), and catalase (CAT) were increased by WAF exposure in a concentration-dependent manner. These results indicated that WAF exposure resulted in oxidative stress, which in turn was associated with dysfunctional development and reproduction. To evaluate the involvement of cytochrome P450 (CYP) genes, we cloned the entire repertoire of CYP genes in T. japonicus (n=52) and found that the CYP genes belonged to five different clans (i.e., Clans 2, 3, 4, mitochondrial, and 20). We then examined expression patterns of these 52 CYP genes in response to WAF exposure. Three TJ-CYP genes (CYP3024A2, CYP3024A3, and CYP3027C2) belonging to CYP clan 3 were significantly induced by WAF exposure in a time- and concentration-dependent manner. We identified aryl hydrocarbon responsive elements (AhRE), xenobiotic responsive elements (XREs), and metal response elements (MRE) in the promoter regions of these three CYP genes, suggesting that these genes are involved in detoxification of toxicants. Overall, our results indicate that WAF can trigger oxidative stress and thus induce dysfunctional development and reproduction in the copepod T. japonicus. Furthermore, we identified three TJ-CYP genes that represent potential biomarkers of oil pollution. PMID:24813263

Han, Jeonghoon; Won, Eun-Ji; Hwang, Dae-Sik; Shin, Kyung-Hoon; Lee, Yong Sung; Leung, Kenneth Mei-Yee; Lee, Su-Jae; Lee, Jae-Seong

2014-07-01

304

Seasonal variation of hydrophobic organic contaminant concentrations in the water-column of the Seine Estuary and their transfer to a planktonic species Eurytemora affinis (Calanoïd, copepod). Part 2: Alkylphenol-polyethoxylates  

Microsoft Academic Search

The occurrence and fate of alkylphenols in various matrices of the Seine River Estuary were studied. Nonylylphenols (NP) and nonylphenol polethoxylates (NPEs) were monitored in surface dissolved water, suspended particulate matter (SPM) and in a copepod, Eurytemora affinis from November 2002 to January 2004. NPs, nonylphenol mono and diethoxylates (NP1EO, NP2EO) and nonylphenol-ethoxy-acetic-acid (NP1EC) were detected and measured in all

K. Cailleaud; J. Forget-Leray; S. Souissi; S. Lardy; S. Augagneur; H. Budzinski

2007-01-01

305

Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region  

NASA Astrophysics Data System (ADS)

As a basis for analyzing development of six large grazing copepods ( Eucalanus bungii, Metridia pacifica, M. okhotensis, Neocalanus cristatus, N. flemingeri and N. plumchrus) in the Oyashio region, quasi-daily twin-NORPAC net (0.33 and 0.10 mm mesh) hauls were taken through the upper 150 m and 500 m at a station southwest of Hokkaido before (9-14 March) and after (6-30 April) the onset of the phytoplankton bloom in 2007. Based on additional fresh specimens collected from 0-150 m, egg production of E. bungii, M. pacifica and M. okhotensis, and gut pigments of late copepodid stages in each species were evaluated. Total zooplankton biomass was greater from 10 April onward by a factor of 2- to 8-fold the previous levels. This increase of the 0-150 m biomass was caused by development of Neocalanus spp. copepodids and upward migration of resting E. bungii. Egg production of E. bungii peaked on 18 April, while abundance of its nauplii and C1 peaked on 20 and 25 April, respectively. Sex ratio and C6-female gonad maturation index of E. bungii showed new recruitment to C6 during 20-30 April, likely derived from a population that over-wintered as C3 or C4. Egg production and hatchability of M. pacifica and M. okhotensis were highly variable and no temporal trend was detected. Comparison with field abundance data for Metridia spp. suggests that our estimates of egg production and hatchability are too low, despite care with experimental conditions. All the Neocalanus species utilize the bloom as energy for juvenile growth. Neocalanus cristatus developed from C2 through C4, and stage duration of C3 was estimated to be 24 days. Neocalanus flemingeri also developed from C1 through C3, and stage durations of C1 and C2 were estimated to be 7-9 days. Neocalanus plumchrus occurred in small numbers from mid-April onward. The stage duration estimates for Neocalanus spp. are similar to those reported from the high-nutrition southeastern Bering Sea shelf. Gut pigment variation clearly showed nocturnal feeding by Metridia spp., while no diel changes in gut pigment were recognized for E. bungii or Neocalanus spp. The diel changes in gut pigment of Metridia spp. were related to their diel vertical migrations. The calendar of sequential responses of copepods to the phytoplankton bloom is summarized.

Yamaguchi, Atsushi; Onishi, Yuka; Omata, Aya; Kawai, Momoka; Kaneda, Mariko; Ikeda, Tsutomu

2010-09-01

306

Evaluation of the zooplankton community of Livingston Reservoir, Texas, as related to paddlefish food resources  

E-print Network

soon after impoundment (Unkenholz 1986). Out of 26 states that contained paddlefish populations historically, 16 still have active paddlefish fishing (Gengerke 1986). Paddlefish are protected in 6 states, but have been extirpated in New York... include larger crustacean zooplankton (Dephnia sp. , larger cyclopoid and calanoid copepods), aquatic insects, and terrestrial insects (Ruelle and Hudson 1977). As paddlefish mature they begin to develop gill rakers, which are rows of fine filaments...

Moore, Casey Kenneth

2012-06-07

307

Interannual and seasonal variation of the population structure, abundance, and biomass of the arctic copepod Calanus glacialis in the White Sea  

NASA Astrophysics Data System (ADS)

The results of multiyear observations of the seasonal and inter-annual variability of the population structure, abundance, and biomass of the arctic calanoids copepod Calanus glacialis in the White Sea are presented. The spring season represents the most crucial period for the population’s seasonal dynamics. During the spring, the maximal abundance, biomass, and contribution of C. glacialis to the total zooplankton biomass is observed. The interannual variability of the abundance is closely related to the timing of the spring warming of the upper water column and the respective shifts of the onset of reproduction and the offspring development. The development of a new generation to the overwintering copepodite stage IV is usually completed three to four weeks later in the cold years compared to the warm ones. Our multiyear observations suggest that C. glacialis could be more tolerant of Arctic warming than it is usually believed. The high abundance of the C. glacialis population in the White Sea indicates that this arctic species is able to cope with the seasonal surface warming and should continue to do so, being provided with the cold water “refuge” in the deep sea.

Pertsova, N. M.; Kosobokova, K. N.

2010-08-01

308

Assemblages gradually change from bathyal to hadal depth: A case study on harpacticoid copepods around the Kuril Trench (north-west Pacific Ocean)  

NASA Astrophysics Data System (ADS)

We investigated the genus diversity and community composition of harpacticoid copepods and their relationship with environmental factors around the Kuril Trench (490-7090 m). Harpacticoid densities did not decrease with water depth and were highest at 1000 m water depth. Diversity values based on the number of genera, Shannon diversity and the expected number of genera (rarefaction) indicated unimodal patterns with water depth, with peaks at intermediate depth; genus evenness increased with water depth and slightly decreased at hadal depths. This result suggested that the general relationship between water depth and diversity described for macrofauna and megafauna could be extended to meiofauna across all depth ranges. However, the regulating factor that affects harpacticoid diversity could not be identified. The community composition of harpacticoids gradually changed with water depth (from bathyal to hadal depths). In addition, comparison of assemblages between the trench slope, trench floor and abyssal plain suggested that the community found at hadal depth was largely different from those found on the trench slope and abyssal plain. Multivariate analyses suggested that water depth, or certain factors associated with water depth, affects harpacticoid assemblages around the Kuril Trench.

Kitahashi, Tomo; Kawamura, Kiichiro; Kojima, Shigeaki; Shimanaga, Motohiro

2013-04-01

309

RNA interference mediated knockdown of the KDEL receptor and COPB2 inhibits digestion and reproduction in the parasitic copepod Lepeophtheirus salmonis.  

PubMed

Retrograde transport of proteins from the endoplasmic reticulum to the Golgi is an essential part of the secretory pathway that all newly synthesised secreted and membrane proteins in eukaryotic cells undergo. The aim of this study was to characterise two components of the retrograde transport pathway in the parasitic copepod Lepeophtheirus salmonis (salmon louse) on a molecular and functional level. LsKDELR and LsCOPB2 were confirmed to be the salmon louse homologues of the chosen target proteins by sequence similarity. Ontogenetic analysis by qRT-PCR revealed the highest expression levels of both genes in adult females and the earliest larval stage. LsKDELR and LsCOPB2 localisation in adult females was detected by immunofluorescence and in situ hybridisation, respectively. Both LsKDELR and LsCOPB2 were found in the ovaries, the oocytes and the gut. LsKDELR and LsCOPB2 were knocked down by RNA interference in preadult females, which was confirmed by qRT-PCR. LsCOPB2 knockdown lice had a significantly higher mortality and failed to develop normally, while both LsCOPB2 and LsKDELR knockdown caused disturbed digestion and the absence of egg strings. This shows the potential of LsKDELR and LsCOPB2 as suitable target candidates for new pest control methods. PMID:24382395

Tröße, Christiane; Nilsen, Frank; Dalvin, Sussie

2014-04-01

310

Testing for beneficial reversal of dominance during salinity shifts in the invasive copepod Eurytemora affinis, and implications for the maintenance of genetic variation.  

PubMed

Maintenance of genetic variation at loci under selection has profound implications for adaptation under environmental change. In temporally and spatially varying habitats, non-neutral polymorphism could be maintained by heterozygote advantage across environments (marginal overdominance), which could be greatly increased by beneficial reversal of dominance across conditions. We tested for reversal of dominance and marginal overdominance in salinity tolerance in the saltwater-to-freshwater invading copepod Eurytemora affinis. We compared survival of F1 offspring generated by crossing saline and freshwater inbred lines (between-salinity F1 crosses) relative to within-salinity F1 crosses, across three salinities. We found evidence for both beneficial reversal of dominance and marginal overdominance in salinity tolerance. In support of reversal of dominance, survival of between-salinity F1 crosses was not different from that of freshwater F1 crosses under freshwater conditions and saltwater F1 crosses under saltwater conditions. In support of marginal overdominance, between-salinity F1 crosses exhibited significantly higher survival across salinities relative to both freshwater and saltwater F1 crosses. Our study provides a rare empirical example of complete beneficial reversal of dominance associated with environmental change. This mechanism might be crucial for maintaining genetic variation in salinity tolerance in E. affinis populations, allowing rapid adaptation to salinity changes during habitat invasions. PMID:25135455

Posavi, Marijan; Gelembiuk, Gregory William; Larget, Bret; Lee, Carol Eunmi

2014-11-01

311

Are individual NOEC levels safe for mixtures? A study on mixture toxicity of brominated flame-retardants in the copepod Nitocra spinipes.  

PubMed

In aquatic ecosystems organisms are exposed to mixtures of pollutants. Still, risk assessment focuses almost exclusively on effect characterization of individual substances. The main objective of the current study was therefore to study mixture toxicity of a common group of industrial substances, i.e., brominated flame-retardants (BFRs), in the harpacticoid copepod Nitocra spinipes. Initially, 10 BFRs with high hydrophobicity but otherwise varying chemical characteristics were selected based on multivariate chemical characterization and tested individually for effects on mortality and development using a partial life cycle test (six days) where silica gel is used as a carrier of the hydrophobic substances. Based on these findings, six of the 10 BFRs were mixed in a series of NOEC proportions (which were set to 0.008, 0.04, 0.2, 1, and five times the NOEC concentrations for each individual BFR), loaded on silica gel and tested in a full life cycle test (26 days). Significantly increased mortality was observed in N. spinipes after six and 26 days exposure at a NOEC proportion that equals the NOEC LDR value (x1) for each BFR in the mixture (p=0.0015 and p=0.0105, respectively). At the NOECx5 proportion all animals were dead. None of the other NOEC proportions caused significant negative responses related to development and reproduction. This shows that low concentrations of individual substances can cause toxicity if exposed in mixtures, which highlights the need to consider mixture toxicity to a greater extent in regulatory work. PMID:18561976

Breitholtz, Magnus; Nyholm, Jenny Rattfelt; Karlsson, Jenny; Andersson, Patrik L

2008-07-01

312

A wax ester and astaxanthin-rich extract from the marine copepod Calanus finmarchicus attenuates atherogenesis in female apolipoprotein E-deficient mice.  

PubMed

The aim of this study was to investigate the effect of dietary supplementation with an oil extracted from the zooplankton copepod Calanus finmarchicus [calanus oil (CO)] on atherosclerosis in apoE-deficient (apoE(-/-)) mice. Thirty 6-wk-old female apoE(-/-) mice (n = 10/group) were fed: 1) a Western-type, high-fat diet (HFD); 2) HFD supplemented with 1% (wt:wt) CO; or 3) HFD supplemented with 0.88% (wt:wt) corn oil + 0.12% (wt:wt) EPA+DHA ethyl esters (EPA+DHA) for 13 wk. Dietary CO supplementation lowered total aorta atherogenesis by 36.5% compared to the HFD (P < 0.01), whereas the reduction in the lesion prone aortic arch was 34.8% (P < 0.01). The degree of aortic atherogenesis was intermediate in mice fed EPA+DHA compared to those fed HFD and CO. The effect on atherogenesis was paralleled by reduced expression of hepatic genes for the proinflammatory cytokines, Ccl2, Icam1, Il1b, and Nfkb1, in mice fed CO compared to those fed HFD. For mice fed EPA+DHA, gene expression did not differ compared to those fed CO or HFD. Plasma concentrations of total cholesterol, TG, and cytokines did not differ between the groups at the end of the study. However, mice fed CO gained more weight compared to those fed HFD but not compared to those fed EPA+DHA. In conclusion, dietary CO supplementation attenuated atherosclerotic lesion formation in female apoE(-/-) mice and may be an effective and safe dietary intervention to reduce the development of atherosclerosis. However, further studies are warranted to elucidate the underlying physiological and molecular mechanisms. PMID:22323762

Eilertsen, Karl-Erik; Mæhre, Hanne K; Jensen, Ida J; Devold, Hege; Olsen, Jan Ole; Lie, Reidun K; Brox, Jan; Berg, Vivian; Elvevoll, Edel O; Osterud, Bjarne

2012-03-01

313

Use of life tables and LC50 tests to evaluate chronic and acute toxicity effects of copper on the marine copepod Tisbe furcata (Baird)  

SciTech Connect

Cohorts of the epiphytic marine copepod Tisbe furcata were chronically exposed to copper in life-table experiments to test whether ecologically relevant impacts can occur at sublethal concentrations. Data on fecundity, longevity, and rate of development were used to calculate r[sub m]--the intrinsic rate of natural increase. Acute toxicity tests were done to compare the concentrations of copper affecting individual lethality and population biology. The LC50 value for Tisbe furcata nauplii was 2.8 [mu]M copper. The results from the life-table experiments show that 0.9 [mu]M copper can cause significant negative effects on demographic parameters (total production of nauplii, life span, and reproductive period for fertile females) and reduce the percentage of fertile females leading to a 61% reduction of r[sub m]. However, r[sub m] was still positive at 0.9 [mu]M copper, and the net reproductive rate (R[sub 0]) indicated a fivefold increase in population size from one generation to the next. Although there were no significant effects of copper at 0.5 [mu]M, there was a negative trend in almost all the demographic parameters, indicating that the observed 10% reduction of r[sub m] at this concentration was an effect of copper. For the substances tested so far with both acute LC50 tests and life-table experiments, r[sub m] was not reduced at concentrations below LC50/10. When life-table experiments are used as part of environmental hazard assessments, concentrations below LC50/10 should be tested to detect substances that are potentially harmful to the environment at sublethal concentrations, rather than testing concentrations close to LC50.

Bechmann, R.K. (Univ. of Oslo (Norway). Dept. of Marine Zoology and Marine Chemistry)

1994-09-01

314

Longitudinal distribution of Copepoda populations in the transition zone of Paranapanema River and Jurumirim Reservoir (São Paulo, Brazil) and interchange with two lateral lakes.  

PubMed

Longitudinal changes in composition, abundance, and distribution of copepods were studied at the transition zone of Paranapanema River-Jurumirim Reservoir (SP, Brazil). The interchange of biotic material between marginal lakes and the river system was also examined. Water samples were obtained from 6 stations along a stretch of 13 km of the Paranapanema River, from an upstream reach with high water velocity up to the river mouth into Jurumirim Reservoir. Two other sites in lateral lakes were also sampled. Nine copepod taxa were identified: 3 calanoids (Argyrodiaptomus furcatus Sars, Notodiaptomus iheringi Wright, and N. conifer Sars) and 6 cyclopoids (Eucyclops Claus, Microcyclops Claus, Mesocyclops longisetus Thiébaud, Thermocyclops decipiens Fischer, T. minutus Lowndes, and Paracyclops Claus). Harpacticoids were also collected. Calanoid and cyclopoid nauplii and copepodids, and harpacticoids were the most abundant organisms. In general, there was a longitudinal decrease in copepod abundance, whereas an increase was detected near the lakes. The abundance of most copepods was inversely correlated with current velocity and suspended solids. Higher abundance was observed in the river main course during the rainy season, during which there is a higher connectivity between the lakes and the main river. This promotes exportation of biologic material from marginal lakes to the river system, a biotic exchange reflecting the importance of marginal lakes to the river community structure. PMID:15195360

Casanova, S M; Henry, R

2004-02-01

315

Population modeling using harpacticoid copepods  

E-print Network

in Applied Environmental Science Department of Applied Environmental Science (ITM Elin Lundström Belleza Department of Applied Environmental Science (ITM) Stockholm of Applied Environmental Science (ITM) Cover by Gian Carlo Belleza, including artwork

316

The diversity of microsporidia in parasitic copepods (Caligidae: Siphonostomatoida) in the Northeast Pacific Ocean with description of Facilispora margolisi n. g., n. sp. and a new Family Facilisporidae n. fam.  

PubMed

Three distinct microsporidia were identified from parasitic copepods in the northeast Pacific Ocean. Sequencing and phylogenetic analysis of a partial small subunit ribosomal RNA gene (SSU rDNA) sequence identified a genetically distinct variety of Desmozoon lepeophtherii from Lepeophtheirus salmonis on cultured Atlantic salmon Salmo salar, and this was confirmed by transmission electron microscopy. Phylogenetic analysis resolved the SSU rDNA sequence of the second organism in a unique lineage that was most similar to microsporidia from marine and brackish water crustaceans. The second occurred in L. salmonis on Atlantic, sockeye Oncorhynchus nerka, chum O. keta and coho O. kisutch salmon, in Lepeophtheirus cuneifer on Atlantic salmon, and in Lepeophtheirus parviventris on Irish Lord Hemilepidotus hemilepidotus. Replication occurred by binary fission during merogony and sporogony, diplokarya were not present, and all stages were in contact with host cell cytoplasm. This parasite was identified as Facilispora margolisi n. g., n. sp. and accommodated within a new family, the Facilisporidae n. fam. The third, from Lepeophtheirus hospitalis on starry flounder Platichthys stellatus, was recognized only from its unique, but clearly microsporidian SSU rDNA sequence. Phylogenetic analysis placed this organism within the clade of microsporidia from crustaceans. PMID:22452386

Jones, Simon R M; Prosperi-Porta, Gina; Kim, Eliah

2012-01-01

317

Changes in seasonal expression patterns of ecdysone receptor, retinoid X receptor and an A-type allatostatin in the copepod, Calanus finmarchicus, in a sea loch environment: an investigation of possible mediators of diapause.  

PubMed

The marine copepod, Calanus finmarchicus, is a crucial component of the pelagic food web in the North Atlantic and peripheral seas where it is a major player in biogeochemical cycles and the productivity of commercially important fisheries. A key stage in its life cycle is the emergence of the pre-adult, copepodite developmental stage five (CV) from a period of overwintering dormancy, known as diapause. As is the case in many insect species, diapause is also likely to be under endocrine control in C. finmarchicus. To investigate the hormonal regulation of diapause behaviour of stage CV C. finmarchicus, the expression of three key genes: ecdysone receptor (EcR), retinoid X receptor (RXR) and an A-type allatostatin (A-type AST), were measured in specimens collected at monthly intervals from Loch Etive, a ca. 150m deep sea loch on the west coast of Scotland, between June 2006 and May 2007. The full length RXR gene was cloned and sequenced from C. finmarchicus, and was found to share 49-53% total identity with equivalent genes encoding proteins from other crustaceans, and >80% identity in the DNA binding domain with other crustaceans, insects and vertebrates. EcR expression was least in December when the animals are expected to be in diapause, but began to increase in January, when the animals were terminating diapause. Concomittant with the rise in EcR in January was low expression of A-type AST and high expression of RXR. PMID:23603431

Clark, Katie A J; Brierley, Andrew S; Pond, David W; Smith, Valerie J

2013-08-01

318

Three species of Agetus (Copepoda, Cyclopoida, Corycaeidae) new to Korean taxa  

NASA Astrophysics Data System (ADS)

The genus Agetus (Cyclopoida, Corycaeidae) has so far been identified by insufficient taxonomic information due to lack of morphological details such as mouthparts, spine lengths of each leg, ornamentation on surface of second urosomal somite. These features are considered as important morphological characteristics in classifying small cyclopoid copepods through taxonomic studies. In this study, some distinct and minute morphological characteristics are used to separate each species within Agetus, with the first redescription of A. typicus, A. flaccus, and A. limbatus from Korean waters. All three species are carefully well redescribed and comparisons with past records from other localities are provided. The zoogeographical distribution has also been summarized.

Wi, Jin Hee; Kim, Dae Hwan; Soh, Ho Young

2013-12-01

319

Zooplankton distribution and feeding in the Arctic Ocean during a Phaeocystis pouchetii bloom  

NASA Astrophysics Data System (ADS)

In early summer 2007 we determined the vertical distribution of mesozooplankton (>200 ?m) and assessed the copepod feeding rates in 19 stations distributed along the East Greenland Current and the Fram Strait. The study coincided with a bloom of the haptophyte Phaeocystis pouchetii in the colonial form. Copepods dominated the zooplankton community numerically, and were mainly distributed within the upper 150 m (except for Metridia longa and Oithona spp., that inhabited deeper waters), without showing a clear avoidance of the P. pouchetii layer. Copepod diet was diverse, ciliates having a relevant share (40% of the diet). Copepods also displayed active grazing upon the colonies of P. pouchetii. In general, feeding rates were low (on average, daily ration was 1.6% of body carbon), likely due to the scarcity of nano and microplankton during the study (<100 ?g C L-1). Consequently, the trophic impacts on both the nano- and microplankton standing stocks and on primary production were negligible. These results suggest that during the period of study the transfer of carbon and energy from lower trophic levels towards copepods was low.

Saiz, Enric; Calbet, Albert; Isari, Stamatina; Antó, Meritxell; Velasco, Eva M.; Almeda, Rodrigo; Movilla, Juancho; Alcaraz, Miquel

2013-02-01

320

Diffusible gas transmitter signaling in the copepod crustacean Calanus finmarchicus: identification of the biosynthetic enzymes of nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S) using a de novo assembled transcriptome.  

PubMed

Neurochemical signaling is a major component of physiological/behavioral control throughout the animal kingdom. Gas transmitters are perhaps the most ancient class of molecules used by nervous systems for chemical communication. Three gases are generally recognized as being produced by neurons: nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S). As part of an ongoing effort to identify and characterize the neurochemical signaling systems of the copepod Calanus finmarchicus, the biomass dominant zooplankton in much of the North Atlantic Ocean, we have mined a de novo assembled transcriptome for sequences encoding the neuronal biosynthetic enzymes of these gases, i.e. nitric oxide synthase (NOS), heme oxygenase (HO) and cystathionine ?-synthase (CBS), respectively. Using Drosophila proteins as queries, two NOS-, one HO-, and one CBS-encoding transcripts were identified. Reverse BLAST and structural analyses of the deduced proteins suggest that each is a true member of its respective enzyme family. RNA-Seq data collected from embryos, early nauplii, late nauplii, early copepodites, late copepodites and adults revealed the expression of each transcript to be stage specific: one NOS restricted primarily to the embryo and the other was absent in the embryo but expressed in all other stages, no CBS expression in the embryo, but present in all other stages, and HO expressed across all developmental stages. Given the importance of gas transmitters in the regulatory control of a number of physiological processes, these data open opportunities for investigating the roles these proteins play under different life-stage and environmental conditions in this ecologically important species. PMID:24747481

Christie, Andrew E; Fontanilla, Tiana M; Roncalli, Vittoria; Cieslak, Matthew C; Lenz, Petra H

2014-06-01

321

Carbon intake by zooplankton. Importance and role of zooplankton grazing in the Indian sector of the Southern Ocean  

NASA Astrophysics Data System (ADS)

Ingestion by mesozooplankton and micronekton was monitored during two of the ANTARES cruises in the Indian sector of the Southern Ocean in spring and summer. The composition of the mesozooplankton populations varied in space and with season. Copepods always dominated in number and biomass, but salps and pteropods were present in the northern part of the transect in summer. Five species of large copepod ( Calanus simillimus, Calanoides acutus, Rhincalanus gigas, Calanus propinquus and Metridia gerlachei) dominated the biomass with a North-South gradient. Smaller species ( Oithona spp., Ctenocalanus citer, Clausocalanus laticeps) were also present. Biomass showed a definite trend with highest levels towards the polar front zone and permanent open-ocean area. Feeding activity was monitored either for the total population (summer) or specific individuals (spring). In summer, depending on the area considered, grazing rates by mesozooplankton appeared to have a significant impact on phytoplankton primary production. In the northern part of the transect (polar front zone or PFZ), salps and to a minor extent pteropods and copepods contributed mostly to the feeding pressure. Maximum intensity was observed in the Coastal Antarctic Zone (CCSZ) where Euphausia superba (adults and calyptopis larvae) could ingest more than 100% of the daily primary production. In spring, the impact of copepods dominated the zooplankton community. Small calanoids and young stages of large species of copepods rather than adult stages were the dominant contributors to grazing pressure. In summer, respiration rates of the dominant copepod species showed that energy expenditure exceeded by far chlorophyll ingestion. This is generally interpreted as the consequence of ingestion of alternate non-chlorophyll food source. The inverse correlation between the biomass of microzooplankton and the area of maximum difference between grazing and respiration confirmed that in summer the protozoans are strongly controlled by the copepod community.

Mayzaud, P.; Tirelli, V.; Errhif, A.; Labat, J. P.; Razouls, S.; Perissinotto, R.

322

Bioaccumulation of trace elements in dominant mesozooplankton group inhabiting in the coastal regions of Indian Sundarban mangrove wetland.  

PubMed

Mesozooplankton (Body size 20-200?m) along with the surface water were collected from coastal regions of Sundarban, northeastern part of Bay of Bengal considering three seasons, namely premonsoon, monsoon and postmonsoon. Samples were analyzed for community structure and the dominant copepod species were further analyzed for trace metal concentration. In total, 50 copepods were identified (22 families and 43 genera). The dominant mesozooplankton species included 9 copepods and an epipelagic chaetognath, exhibited both spatial and seasonal variations. Metal concentration exhibited considerable inter-specific variations for the copepods and the mean concentrations were: Fe, 1350.2-51118.3?g/g; Al, 647.2-73019.1?g/g; Ni, 32.4-110.3?g/g; Mn, 122.8-1066.5?g/g; Pb, 0.04-97.5?g/g; Pb, 10.6-97.5?g/g; Cd, 4.2-21.6?g/g; Cu, 17.4-145.1?g/g; Zn, 225.7-1670.9?g/g; Cr, 21.7-194.3?g/g; Co, 1.32-111.1?g/g. Metal concentrations showed the following order: Sagitta bedoti>Coryceas danae>Oithona sp.>Eucalanus subcrassus>Labidocera euchaeta>Paracalanus parvus>Acartiella tortaniformis>Acartia spinicauda>Pseudocalanus serricaudatus. PMID:25110048

Bhattacharya, Bhaskar Deb; Hwang, Jiang-Shiou; Tseng, Li-Chun; Sarkar, Santosh Kumar; Rakshit, Dibyendu; Mitra, Soumita

2014-10-15

323

Predation on Mosquito Larvae by Mesocyclops thermocyclopoides (Copepoda: Cyclopoida) in the Presence of Alternate Prey  

NASA Astrophysics Data System (ADS)

The cyclopoid copepod Mesocyclops thermocyclopoides, a dominant invertebrate predator in many shallow ponds and temporary water bodies in northern India, feeds on cladocerans, rotifers, ciliates and when present, on mosquito larvae also. We studied in the laboratory the prey consumption rates of the copepod on first and fourth instar larvae of two species of mosquito (Anopheles stephensi and Culex quinquefasciatus) in relation to their density. We also studied its prey selectivity with mosquito larvae in the presence of an alternate prey (the cladocerans-either Moina macrocopa or Ceriodaphnia cornuta) in different proportions. With either mosquito species, the copepod actively selected Instar-I larvae, avoiding the Instar-IV larvae, and with either instar, selected Anopheles stephensi over Culex quinquefasciatus. When prey choice included the cladoceran as an alternate prey, the copepod selected the cladoceran only when the other prey was Instar-IV mosquito larvae. Our results point to the potential and promise of M. thermocyclopoides as a biological agent for controlling larval populations of vectorially important mosquito species.

Kumar, Ram; Ramakrishna Rao, T.

2003-11-01

324

Composition of phytoplankton communities and their contribution to secondary productivity in Carolina Bays on the Savannah River Plant  

SciTech Connect

The overall goal of the this three year project is to determine the importance of phytoplankton (microscopic algae) as a component of the food chain base in SRS cardine bays. To summarize specific year three results: Total phytoplankton abundance in Flamingo bay was greatest during early spring 1989, declined during spring and summer, but increased again during early fall. Most of this phytoplankton density was composed of genus Chlamydomonas sp. Ellenton bay demonstrated a similar decline in phytoplankton numbers during midspring 1989, but increased in density during midsummer. As observed in Flamingo bay, much of this variation was due to changes in Chlamydomonas sp. numbers. In Flamingo bay the blue-green alga Anabaena sp. was low in concentration throughout the 1989 flooded season until August, however the diatom Pinnularia sp. displayed a pattern of abundance similar to Chlamydomonas sp. In Ellenton bay Pinnularia sp. peaked during early summer and Anabaena sp. reached highest densities in late spring. For zooplankton in Flamingo bay, the calanoid copepods were higher in early and late spring, similar to the cyclopoid copepods. Cladocera in Ellenton bay were highest in numbers during May 1989, while cladocera in Flamingo bay displayed patterns similar to Flamingo bay cyclopoid copepods. Laboratory experiments exposing Chlamydomonas sp. cultures to known mixtures of {sup 13}C-CO{sub 2} and {sup 12}C-CO{sub 2} seem to indicate that some isotope preference may exist during photosynthesis, however these results have not been analyzed statistically yet. Phytoplankton samples collected for Flamingo bay indicated that a seasonal change in isotope ratios may be occurring in algae tissues, however further analyses are being conducted to determine whether this may also be due to species shifts. 3 refs., 14 figs.

Williams, J.B.

1991-08-01

325

Association of bacteria with marine invertebrates: implications for ballast water management.  

PubMed

Bacteria associated with plankton are of importance in marine bioinvasions and the implementation of ship's ballast water treatment technologies. In this study, epibiotic and endobiotic bacteria associated with zooplankton, including barnacle nauplii, veliger larvae, and adults of the copepod Oithona sp., were characterized and quantified. Barnacle nauplius and veliger larva harbored ~4.4 × 10(5)cells ind(-1) whereas Oithona sp. had 8.8 × 10(5)cells ind(-1). Computation of bacterial contribution based on biovolume indicated that despite being the smallest zooplankton tested, veliger larvae harbored the highest number of bacteria, while barnacle nauplii, the largest of the zooplankton, tested in terms of volume contributed the least. Pulverization of zooplankton led to an increase in bacterial numbers; for example, Vibrio cholerae, which was initially 3.5 × 10(3), increased to 5.4 × 10(5)CFU g(-1); Escherichia coli increased from 5.0 × 10(2) to 1.3 × 10(4)CFU g(-1); and Streptococcus faecalis increased from 2.1 × 10(2) to 2.5 × 10(5)CFU g(-1), respectively. Pulverized zooplankton was aged in the dark to assess the contribution of bacteria from decaying debris. Aging of pulverized zooplankton led to emergence of Chromobacterium violaceum, which is an opportunistic pathogen in animals and humans. PMID:23846742

Khandeparker, Lidita; Anil, Arga Chandrashekar

2013-09-01

326

A Molecular and Co-Evolutionary Context for Grazer Induced Toxin Production in Alexandrium tamarense  

PubMed Central

Marine dinoflagellates of the genus Alexandrium are the proximal source of neurotoxins associated with Paralytic Shellfish Poisoning. The production of these toxins, the toxin biosynthesis and, thus, the cellular toxicity can be influenced by abiotic and biotic factors. There is, however, a lack of substantial evidence concerning the toxins' ecological function such as grazing defense. Waterborne cues from copepods have been previously found to induce a species-specific increase in toxin content in Alexandrium minutum. However, it remains speculative in which context these species-specific responses evolved and if it occurs in other Alexandrium species as well. In this study we exposed Alexandrium tamarense to three copepod species (Calanus helgolandicus, Acartia clausii, and Oithona similis) and their corresponding cues. We show that the species-specific response towards copepod-cues is not restricted to one Alexandrium species and that co-evolutionary processes might be involved in these responses, thus giving additional evidence for the defensive role of phycotoxins. Through a functional genomic approach we gained insights into the underlying molecular processes which could trigger the different outcomes of these species-specific responses and consequently lead to increased toxin content in Alexandrium tamarense. We propose that the regulation of serine/threonine kinase signaling pathways has a major influence in directing the external stimuli i.e. copepod-cues, into different intracellular cascades and networks in A. tamarense. Our results show that A. tamarense can sense potential predating copepods and respond to the received information by increasing its toxin production. Furthermore, we demonstrate how a functional genomic approach can be used to investigate species interactions within the plankton community. PMID:21124775

Wohlrab, Sylke; Iversen, Morten H.; John, Uwe

2010-01-01

327

The seasonal cycle of the epipelagic mesozooplankton in the northern Gulf of Aqaba (Red Sea)  

NASA Astrophysics Data System (ADS)

The abundance and composition of the mesozooplankton were studied in the upper 100 m of the northern Gulf of Aqaba over a period of 22 months between February 2002 and December 2003. The samples were collected monthly with a Nansen net of 200 ?m mesh size. The abundance of total mesozooplankton ranged between 245 and 3065 ind. m - 3 . Highest densities in 2002 were recorded in spring (March/April) and in autumn (October/November), while several peaks occurred in 2003 with maximum abundance in early summer (June/July). Copepods dominated the mesozooplankton community during the whole sampling period (mean 79%). Molluscs ranked secondly (8%), followed by appendicularians (2.5%) and chaetognaths (2.4%). All other taxa contributed only a small fraction of the total mesozooplankton population (0.3%). Within the copepods, calanoids were predominant throughout the sampling period (41-83%. mean 61%). Cyclopoid copepods accounted for 17 and 59% (mean 37%) while harpacticoids occurred only in very low numbers (less than 1%). Within the calanoid copepods, smaller sized taxa were abundant, belonging to the families of Clausocalanidae, Paracalanidae, Calocalanidae, Acartiidae and Mecynoceridae. Together they accounted for 84 to 98% of the calanoids. A performed cluster analysis revealed significant difference between the samples from January to May and those from June to December. Accordingly, the abundant calanoid copepod taxa could be divided into two groups: firstly, taxa with high abundance during the transition from winter-spring transition (onset of thermal stratification) and secondly, taxa with high densities during the disintegration of the stratification in autumn. The taxa of the second group showed a positive significant correlation to the annual cycle of temperature, indicating a strong relationship with seasonal changes in the hydrographic features of the Gulf of Aqaba.

Cornils, A.; Schnack-Schiel, S. B.; Al-Najjar, T.; Badran, M. I.; Rasheed, M.; Manasreh, R.; Richter, C.

2007-11-01

328

Seasonal cycles of zooplankton from San Francisco Bay  

USGS Publications Warehouse

The two estuarine systems composing San Francisco Bay have distinct zooplankton communities and seasonal population dynamics. In the South Bay, a shallow lagoon-type estuary, the copepods Acartia spp. and Oithona davisae dominate. As in estuaries along the northeast coast of the U.S., there is a seasonal succession involving the replacement of a cold-season Acartia species (A. clausi s.l.) by a warm-season species (A. californiensis), presumably resulting from the differential production and hatching of dormant eggs. Oithona davisae is most abundant during the fall. Copepods of northern San Francisco Bay, a partially-mixed estuary of the Sacramento-San Joaquin Rivers, organize into discrete populations according to salinity distribution: Sinocalanus doerrii (a recently introduced species) at the riverine boundary, Eurytemora affinis in the oligohaline mixing zone, Acartia spp. in polyhaline waters (18-30\\%), and neritic species (e.g., Paracalanus parvus) at the seaward boundary. Sinocalanus doerrii and E. affinis are present year-round. Acartia clausi s.l. is present almost year-round in the northern reach, and A. californiensis occurs only briefly there in summer-fall. The difference in succession of Acartia species between the two regions of San Francisco Bay may reflect differences in the seasonal temperature cycle (the South Bay warms earlier), and the perennial transport of A. clausi s.l. into the northern reach from the seaward boundary by nontidal advection. Large numbers (>106 m-3) of net microzooplankton (>64 ??m), in cluding the rotifer Synchaeta sp. and three species of tintinnid ciliates, occur in the South Bay and in the seaward northern reach where salinity exceeds about 5-10??? Maximum densities of these microzooplankton are associated with high concentrations of chlorophyll. Meroplankton (of gastropods, bivalves, barnacles, and polychaetes) constitute a large fraction of zooplankton biomass in the South Bay during winter-spring and in the northern reach during summer-fall. Seasonal cycles of zooplankton abundance appear to be constant among years (1978-1981) and are similar in the deep (>10 m) channels and lateral shoals (<3 m). The seasonal zooplankton community dynamics are discussed in relation to: (1) river discharge which alters salinity distribution and residence time of plankton; (2) temperature which induces production and hatching of dormant copepod eggs; (3) coastal hydrography which brings neritic copepods of different zoogeographic affinities into the bay; and (4) seasonal cycles of phytoplankton. ?? 1985 Dr W. Junk Publishers.

Ambler, J. W.; Cloern, J. E.; Hutchinson, A.

1985-01-01

329

Taxonomy, ecology, and geographical distribution of the species of the genus Thermocyclops Kiefer, 1927 (Copepoda, Cyclopoida) in São Paulo State, Brazil, with description of a new species.  

PubMed

The taxonomy and ecology of the cyclopoid copepod genus Thermocyclops were studied. Samples were collected in 207 water bodies located in the 22 hydrographic basins of São Paulo State, Brazil, including large reservoirs, small and shallow lakes, and ponds and rivers. The genus Thermocyclops inhabits mainly water bodies within a limnetic region. Four species were found, of which one is new: Thermocyclops iguapensis, which occurred in the reservoirs of the Ribeira do Iguape and Paraíba do Sul basins. The description of the new species and the geographical distribution of all four species in São Paulo State are presented. Thermocyclops decipiens was the most frequent species, occurring in 71% of the water bodies within a limnetic region. This species is characteristic of eutrophic environments where it can occur in great abundance, whereas Thermocyclops minutus is characteristic in oligotrophic systems. Thermocyclops inversus and Thermocyclops iguapensis n. sp. were not common but can occur together with Thermocyclops decipiens. PMID:16341431

Silva, W M; Matsumura-Tundisi, T

2005-08-01

330

Carnivorous planktonic Difflugia (Protista, Amoebina Testacea) and their predators.  

PubMed

Four planktonic species of Difflugia co-occurring in a south Chinese reservoir were found to be carnivorous, but the diet was widest in the largest species (D. tuberspinifera) and narrowest in the smallest (D. hydrostatica). It included rotifers, ciliates, dinoflagellates, floating eggs, and small particles associated with organic debris. Scavenging and cannibalism were also observed. Species with a collared test (D. biwae, D. mulanensis) showed a form of suction-feeding, while species with teeth on the pseudostome used these, together with their pseudopods, as "inverted crown corks", providing leverage for opening the lorica of their (rotifer) prey. Predators of Difflugia included cyclopoid copepods. In addition, the rotifers Asplanchna priodonta, Ploesoma hudsoni and, occasionally, big ciliates (Stentor sp.) all ingested their prey as a whole. PMID:21632222

Han, Bo-Ping; Wang, Tian; Xu, Lei; Lin, Qiu Qi; Jinyu, Zhang; Dumont, Henri J

2011-08-01

331

Food and feeding in Northern krill (Meganyctiphanes norvegica Sars).  

PubMed

Early feeding studies on Meganyctiphanes norvegica described the morphology of the feeding appendages and the actual process of food uptake and digestion. Insights into diurnal, seasonal and ontogenetic pattern in feeding activity and diet were derived from field studies on the Clyde Sea population. Since then, technical advances have confirmed some of the early assumptions and rejected others. Submersible, remotely operated vehicles and echosounders, for instance, proved that M. norvegica stay often close to the seabed and feed on particles in the epibenthic layer and sediment-water interface. Scanning electron microscopy showed that mandibles of the so-called carnivorous M. norvegica have an elaborated grinding region, which allows efficient feeding on diatoms. Three-dimensional silhouette video imaging revealed mechanoreception, not vision, as the main sensory modality involved in proximity prey detection by M. norvegica. Fatty acid analysis and stomach content microscopy have now been conducted on M. norvegica across a range of environments including the Gulf of Maine, Greenland Sea, Barents Sea, Scandinavian fjords, the Kattegat and Mediterranean Sea. Regional and seasonal differences in the trophic environment are reflected in their daily ration and in the relative importance of copepods versus phytoplankton in their diet. Overall, phytoplankton is an important food source for M. norvegica during the spring bloom and part of the summer, but copepods are dominant in autumn and winter. Depending on their vertical co-occurrence, M. norvegica can feed on a range of copepods from early stages of Oithona spp. up to adult Calanus spp. There are clear ontogenetic differences in diet, with adults feeding more on copepods and benthic food items than early post-larvae. Future studies should link diet to simultaneously measured growth and reproduction and emphasise comparison across the spectrum of environments inhabited by this versatile species. PMID:20955891

Schmidt, Katrin

2010-01-01

332

Surface zooplankton distribution patterns during austral summer in the Indian sector of the Southern Ocean, south of Australia  

NASA Astrophysics Data System (ADS)

We investigated the composition, distribution and abundance of micro- and mesozooplankton in the Southern Ocean, south of Australia during the austral summer (December-February) of the 2007/08 season using a Continuous Plankton Recorder (CPR). Four CPR tows were conducted during two separate oceanographic voyages under the CEAMARC (Collaborative East Antarctic Marine Census) project. High zooplankton abundance was recorded on each transect in the Polar Frontal Zone (PFZ) and the Inter Polar Frontal Zone (IPFZ). The community structure in these zones was dominated by common taxa including the ubiquitous small calanoid copepods, Oithona similis and Calanus simillimus, accounting for >70% of the total abundance, and copepod nauplii, foraminiferans and appendicularians of the genus Fritillaria spp. also occurred along most of the survey transects. Total zooplankton abundance was comparatively consistent along the four transects, and ranged between 119.8 and 144.7 ind m -3. The results of cluster and IndVal analyses revealed that the dominant species/taxa show similar associations, abundance and distribution patterns on all four transects. There was no evidence of a change of surface zooplankton abundance at the time of towing in this study. Detecting the various distribution patterns of micro- and mesozooplankton species/taxa, and the accumulation of high quality data collected by a consistent methodology will contribute to determining the consequences of climate change impacts on the ecosystem.

Takahashi, Kunio T.; Hosie, Graham W.; McLeod, David J.; Kitchener, John A.

2011-08-01

333

Secondary production at the Polar Front, Barents Sea, August 2007  

NASA Astrophysics Data System (ADS)

To investigate spatial patterns of secondary production we sampled four core hydrographical regions of the Polar Front in the Barents Sea (Arctic Water, ArW; Polar Front Water, PFW; Atlantic Water, AtW; and Melt Water, MW) by towing an undulating instrument platform along a transect crossing the front from August 8-9, 2007. Sensors mounted on the platform provided data on the hydrography (CTD), fluorescence (Fluorometer, F) and zooplankton abundance in the size range between 0.1 and 30 mm (Laser Optical Plankton Counter, LOPC). These continuous, biophysical data with high-spatial resolution were supplemented by discrete water and zooplankton net samples at stations for sensor calibrations. After in depth quality assessments of the biophysical data, estimates were made of the vital rates based on biovolume spectrum theory. Five size groups were distinguished from the LOPC data: small (S), mainly Oithona spp. and the appendicularian Fritillaria sp.; medium (M), mainly Pseudocalanus spp. and Calanus spp. CI-CIII; large (L), mainly Calanus spp. CIV-CV; and extra large (XL and 2XL), juvenile and adult euphausids. Size groups were further divided based on transparency of organisms. Vital rates based on the biophysical in situ data in combination with biovolume spectrum theories agreed generally well with data from empirical and numerical models in the literature. ArW was characterised by subsurface maxima of chlorophyll a (chl a), and an estimated population growth of ca. 13 mg C m- 3 d- 1 for CI-CIII Calanus spp. and some older Pseudocalanus within the chl a maxima. Frontal waters were characterised by low chl a concentrations, but high abundances and production (around 1 g C m- 3 d- 1) of small copepods (Oithona spp.) and appendicularians (Fritillaria sp.). The estimated production of small-size zooplankton was an order of magnitude higher than the production of all other size groups combined, including large copepods. The high loss rates (- 166 to - 271 mg C m- 3 d- 1) of small zooplankton may contribute a substantial amount of carbon to the benthos and to pelagic predators such as young capelin. AtW was the most productive water mass, with surface chl a maxima and an estimated population growth of 134 mg C m- 3 d- 1 for small zooplankton, 3.6 mg C m- 3 d- 1 for medium-sized copepods and 0.9 mg C m- 3 d- 1 for CIV-CVI Calanus. For those Calanus spp. in the surface layer, the estimated specific mortality rates were up to - 0.35 d- 1, partly due to high predation pressure by hydrozoans and chaetognaths.

Basedow, Sünnje L.; Zhou, Meng; Tande, Kurt S.

2014-02-01

334

Diversity and Seasonality of Bioluminescent Vibrio cholerae Populations in Chesapeake Bay?  

PubMed Central

Association of luminescence with phenotypic and genotypic traits and with environmental parameters was determined for 278 strains of Vibrio cholerae isolated from the Chesapeake Bay during 1998 to 2000. Three clusters of luminescent strains (A, B, and C) and two nonluminescent clusters (X and Y) were identified among 180 clonal types. V. cholerae O1 strains isolated during pandemics and endemic cholera in the Ganges Delta were related to cluster Y. Heat-stable enterotoxin (encoded by stn) and the membrane protein associated with bile resistance (encoded by ompU) were found to be linked to luminescence in strains of cluster A. Succession from nonluminescent to luminescent populations of V. cholerae occurred during spring to midsummer. Occurrence of cluster A strains in water with neutral pH was contrasted with that of cluster Y strains in water with a pH of >8. Cluster A was found to be associated with a specific calanoid population cooccurring with cyclopoids. Cluster B was related to cluster Y, with its maximal prevalence at pH 8. Occurrence of cluster B strains was more frequent with warmer water temperatures and negatively correlated with maturity of the copepod community. It is concluded that each cluster of luminescent V. cholerae strains occupies a distinct ecological niche. Since the dynamics of these niche-specific subpopulations are associated with zooplankton community composition, the ecology of luminescent V. cholerae is concluded to be related to its interaction with copepods and related crustacean species. PMID:19011071

Zo, Young-Gun; Chokesajjawatee, Nipa; Grim, Christopher; Arakawa, Eiji; Watanabe, Haruo; Colwell, Rita R.

2009-01-01

335

Feeding ecology of lake whitefish larvae in eastern Lake Ontario  

USGS Publications Warehouse

We examined the feeding ecology of larval lake whitefish (Coregonus clupeaformis) in Chaumont Bay, Lake Ontario, during April and May 2004-2006. Larvae were collected with towed ichthyoplankton nets offshore and with larval seines along the shoreline. Larval feeding periodicity was examined from collections made at 4-h intervals over one 24-h period in 2005. Inter-annual variation in diet composition (% dry weight) was low, as was spatial variation among collection sites within the bay. Copepods (81.4%), primarily cyclopoids (59.1%), were the primary prey of larvae over the 3-year period. Cladocerans (8.1%; mainly daphnids, 6.7%) and chironomids (7.3%) were the other major prey consumed. Larvae did not exhibit a preference for any specific prey taxa. Food consumption of lake whitefish larvae was significantly lower at night (i.e., 2400 and 0400 h). Substantial variation in diet composition occurred over the 24-h diel study. For the 24-h period, copepods were the major prey consumed (50.4%) and their contribution in the diet ranged from 29.3% (0400 h) to 85.9% (1200 h). Chironomids made up 33.4% of the diel diet, ranging from 8.0% (0800 h) to 69.9% (0400 h). Diel variation in the diet composition of lake whitefish larvae may require samples taken at several intervals over a 24-h period to gain adequate representation of their feeding ecology.

Johnson, James H.; McKenna, James E.; Chalupnicki, Marc A.; Wallbridge, Tim; Chiavelli, Rich

2009-01-01

336

Scaling-up anti-predator phenotypic responses of prey: impacts over multiple generations in a complex aquatic community  

PubMed Central

Non-consumptive effects (NCEs) of predators owing to induced changes in prey traits are predicted to influence the structure of ecological communities. However, evidence of the importance of NCEs is limited primarily to simple systems (e.g. two to four species) over relatively short periods (e.g. less than one generation). We examined the NCEs of a fish predator, arising from phenotypic plasticity in zooplankton prey traits, over multiple generations of a diverse zooplankton community. The presence of fish, caged to remove consumptive effects, strongly influenced zooplankton community structure, through both direct and indirect NCE pathways, altering the abundance of many taxa by magnitudes as large as 3 to 10-fold. Presence of fish affected different species of cladocerans and copepods both positively and negatively. A particularly striking result was the reversal of dominance in copepod taxa: presence of fish reduced the ratio of calanoids to cyclopoids from 6.3 to 0.43. Further, the NCE of fish had a strong negative trophic cascade to zooplankton resources (phytoplankton). To our knowledge, this is the first experiment to show that NCEs can influence the abundance of multiple prey species over time spans of multiple prey generations. Our findings demonstrate that adaptive phenotypic plasticity of individuals can scale-up to affect the structure of ecological communities. PMID:21593036

Peacor, Scott D.; Pangle, Kevin L.; Schiesari, Luis; Werner, Earl E.

2012-01-01

337

ORIGINAL PAPER Identifying non-invasible habitats for marine copepods  

E-print Network

produced by a female over its lifetime, and has been used as a metric of population persistence. We modeled Pseudodiaptomus marinus, which is introduced to west coast of North America from East Asia by ship ballast water. The model was based on temperature- dependent stage-structured population dynamics given by a system

Lewis, Mark

338

Novel Organization and Development of Copepod Myelin. II. Nonglial Origin  

E-print Network

. VC 2011 Wiley-Liss, Inc. INDEXING TERMS: Crustacea; neuron; nervous system; glia; ultrastructure an order of magnitude increase in nerve impulse conduction speed and several orders decrease in metabolic, the oligodendrocyte, was impli- cated (Bunge et al., 1962). In invertebrates, the origin of myelin from glial cells

Hartline, Daniel K.

339

Marine copepod diversity patterns and the metabolic theory of ecology  

Microsoft Academic Search

Temperature is a powerful correlate of large-scale terrestrial and marine diversity patterns but the mechanistic links remain\\u000a unclear. Whilst many explanations have been proposed, quantitative predictions that allow them to be tested statistically\\u000a are often lacking. As an important exception, the metabolic theory of ecology (MTE) provides a rather robust technique using\\u000a the relationship between diversity, temperature and metabolic rate

Isabelle Rombouts; Grégory Beaugrand; Frédéric Iba?ez; Sanae Chiba; Louis Legendre

2011-01-01

340

Vertical and temporal distribution of two copepod species, Cyclops scutifer  

E-print Network

.J. Flynn Factors structuring zooplankton communities in areas with 24 h of sunlight are not well under- stood. In stratified temperate lakes with fish, zooplankton generally undergo a diel vertical migration. To explore factors that determine vertical structure of zooplankton where DVM does not occur, we obtained

California at Santa Barbara, University of

341

copepods, ostracods, isopods, amphipods, mysids, and cumaceans, as well as  

E-print Network

of the coast (Figure 1) and many contain sea level pools in their interior. Such pools. both at entrances and catalog the fauna of Bermuda's caves. In September 1979, I invited Paul Meng, a Florida-based cave diving done some cave diving while obtaining my Masters degree in Oceanography at Florida State and later when

Iliffe, Thomas M.

342

Development of a Halotolerant Community in the St. Lucia Estuary (South Africa) during a Hypersaline Phase  

PubMed Central

Background The St. Lucia Estuary, Africa's largest estuarine lake, is currently experiencing unprecedented freshwater deprivation which has resulted in a northward gradient of drought effects, with hypersaline conditions in its northern lakes. Methodology/Principal Findings This study documents the changes that occurred in the biotic communities at False Bay from May 2010 to June 2011, in order to better understand ecosystem functioning in hypersaline habitats. Few zooplankton taxa were able to withstand the harsh environmental conditions during 2010. These were the flatworm Macrostomum sp., the harpacticoid copepod Cletocamptus confluens, the cyclopoid copepod Apocyclops cf. dengizicus and the ciliate Fabrea cf. salina. In addition to their exceptional salinity tolerance, they were involved in a remarkably simple food web. In June 2009, a bloom of an orange-pigmented cyanobacterium (Cyanothece sp.) was recorded in False Bay and persisted uninterruptedly for 18 months. Stable isotope analysis suggests that this cyanobacterium was the main prey item of F. cf. salina. This ciliate was then consumed by A. cf. dengizicus, which in turn was presumably consumed by flamingos as they flocked in the area when the copepods attained swarming densities. On the shore, cyanobacteria mats contributed to a population explosion of the staphylinid beetle Bledius pilicollis. Although zooplankton disappeared once salinities exceeded 130, many taxa are capable of producing spores or resting cysts to bridge harsh periods. The hypersaline community was disrupted by heavy summer rains in 2011, which alleviated drought conditions and resulted in a sharp increase in zooplankton stock and diversity. Conclusions/Significance Despite the current freshwater deprivation crisis, the False Bay region has shown to be resilient, harboring a unique biodiversity with species that are capable of enduring harsh environmental conditions. However, further freshwater deprivation may extend beyond the physiological thresholds of this community, as well as other unique biodiversity components which this system sustains. PMID:22238676

Carrasco, Nicola K.; Perissinotto, Renzo

2012-01-01

343

Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River  

USGS Publications Warehouse

As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook salmon. Juvenile American shad were abundant and represented over 98% of the trawl catch in late summer. The five major taxa collected in zooplankton tows were Bosmina longirostris, Daphnia, cyclopoid cope-pods, rotifers, and calanoid copepods. We evaluated total crustacean zooplankton abundance and Daphnia biomass in relation to water temperature, flow, depth, diel period, and cross-sectional location using multiple regression. Differences in zooplankton abundance were largely due to differences in water temperature and flow. Spatial variation in total zooplankton abundance was observed in McNary Reservoir, but not in John Day Reservoir. Juvenile American shad generally fed on numerically abundant prey, despite being less preferred than larger bodied zooplankton. A decrease in cladoceran abundance and size in August coupled with large percentages of Daphnia in juvenile American shad stomachs indicated heavy planktivory. Smaller juvenile American shad primarily fed on Daphnia in August, but switched to more evasive copepods as the mean size of fish increased and Daphnia abundance declined. Because Daphnia are particularly important prey items for subyearling Chinook salmon in mainstem reservoirs in mid to late summer, alterations in the cladoceran food base is of concern for the management of outmigrating salmonids and other Columbia River fishes. ?? 2006 by the Northwest Scientific Association. All rights reserved.

Haskell, C. A.; Tiffan, K. F.; Rondorf, D. W.

2006-01-01

344

Latitudinal and taxonomic patterns in the feeding ecologies of fish larvae: A literature synthesis  

NASA Astrophysics Data System (ADS)

The longtime focus on factors that influence the survival of marine fish larvae has yielded an extensive number of studies on larval fish diets and feeding success. In light of a recent increase in such studies within lower latitudes, results from the peer-reviewed literature were synthesized to examine both latitudinal and taxonomic differences in several trophic-related categories, including feeding incidence, trophic niche breadth, ontogenetic diet shifts, dominant prey types, diet broadness, and larval piscivory. A total of 204 investigations (taxon-article combinations) contained suitable results for at least one of these categories. Feeding incidences (proportions of larvae containing food) were significantly higher in lower latitudes with all taxa combined, as well as only within the order Perciformes. Feeding incidences also differed among orders, with Perciformes and Scorpaeniformes having the highest values. The number of larval taxa exhibiting a significantly increasing niche breadth (SD of the log of prey sizes) with larval size decreased toward lower latitudes, with some taxa in lower latitudes exhibiting a decrease in niche breadth with size. The frequency of exhibiting ontogenetic diets shifts decreased with decreasing latitude, as did relative diet broadness (a function of prey types). The most common dominant prey types in the diets of higher latitude larvae were nauplii and calanoid copepods, with cyclopoids being rare in higher latitudes. Dominant prey types in lower latitudes were more diverse, with nauplii, calanoids, and cyclopoids being equally important. Appendicularians increased in importance with decreasing latitude, and one of the clearest latitudinal distinctions was the display of larval piscivory (almost exclusively by scombroid taxa), which was highly concentrated in lower latitudes. Overall, the latitudinal differences observed for multiple trophic-related factors highlight inherent distinctions in larval fish feeding ecologies, likely reflecting differences in the overall structure of planktonic food webs over large latitudinal gradients.

Llopiz, Joel K.

2013-01-01

345

Combined effects of turbulence and different predation regimes on zooplankton in highly colored water-implications for environmental change in lakes.  

PubMed

In aquatic ecosystems, predation is affected both by turbulence and visibility, but the combined effects are poorly known. Both factors are changing in lakes in the Northern Hemisphere; the average levels of turbulence are predicted to increase due to increasing wind activities, while water transparency is decreasing, e.g., due to variations in precipitation, and sediment resuspension. We explored experimentally how turbulence influenced the effects of planktivorous fish and invertebrate predators on zooplankton when it was combined with low visibility caused by high levels of water color. The study was conducted as a factorial design in 24 outdoor ponds, using the natural zooplankton community as a prey population. Perch and roach were used as vertebrate predators and Chaoborus flavicans larvae as invertebrate predators. In addition to calm conditions, the turbulent dissipation rate used in the experiments was 10-6 m2 s-3, and the water color was 140 mg Pt L-1. The results demonstrated that in a system dominated by invertebrates, predation pressure on cladocerans increased considerably under intermediate turbulence. Under calm conditions, chaoborids caused only a minor reduction in the crustacean biomass. The effect of fish predation on cladocerans was slightly reduced by turbulence, while predation on cyclopoids was strongly enhanced. Surprisingly, under turbulent conditions fish reduced cyclopoid biomass, whereas in calm water it increased in the presence of fish. We thus concluded that turbulence affects fish selectivity. The results suggested that in dystrophic invertebrate-dominated lakes, turbulence may severely affect the abundance of cladocerans. In fish-dominated dystrophic lakes, on the other hand, turbulence-induced changes in planktivory may considerably affect copepods instead of cladocerans. In lakes inhabited by both invertebrates and fish, the response of top-down regulation to turbulence resembles that in fish-dominated systems, due to intraguild predation. The changes in planktivorous predation induced by abiotic factors may possibly cascade to primary producers. PMID:25375952

Härkönen, Laura; Pekcan-Hekim, Zeynep; Hellén, Noora; Ojala, Anne; Horppila, Jukka

2014-01-01

346

Combined Effects of Turbulence and Different Predation Regimes on Zooplankton in Highly Colored Water—Implications for Environmental Change in Lakes  

PubMed Central

In aquatic ecosystems, predation is affected both by turbulence and visibility, but the combined effects are poorly known. Both factors are changing in lakes in the Northern Hemisphere; the average levels of turbulence are predicted to increase due to increasing wind activities, while water transparency is decreasing, e.g., due to variations in precipitation, and sediment resuspension. We explored experimentally how turbulence influenced the effects of planktivorous fish and invertebrate predators on zooplankton when it was combined with low visibility caused by high levels of water color. The study was conducted as a factorial design in 24 outdoor ponds, using the natural zooplankton community as a prey population. Perch and roach were used as vertebrate predators and Chaoborus flavicans larvae as invertebrate predators. In addition to calm conditions, the turbulent dissipation rate used in the experiments was 10?6 m2 s?3, and the water color was 140 mg Pt L?1. The results demonstrated that in a system dominated by invertebrates, predation pressure on cladocerans increased considerably under intermediate turbulence. Under calm conditions, chaoborids caused only a minor reduction in the crustacean biomass. The effect of fish predation on cladocerans was slightly reduced by turbulence, while predation on cyclopoids was strongly enhanced. Surprisingly, under turbulent conditions fish reduced cyclopoid biomass, whereas in calm water it increased in the presence of fish. We thus concluded that turbulence affects fish selectivity. The results suggested that in dystrophic invertebrate-dominated lakes, turbulence may severely affect the abundance of cladocerans. In fish-dominated dystrophic lakes, on the other hand, turbulence-induced changes in planktivory may considerably affect copepods instead of cladocerans. In lakes inhabited by both invertebrates and fish, the response of top-down regulation to turbulence resembles that in fish-dominated systems, due to intraguild predation. The changes in planktivorous predation induced by abiotic factors may possibly cascade to primary producers. PMID:25375952

Härkönen, Laura; Pekcan-Hekim, Zeynep; Hellén, Noora; Ojala, Anne; Horppila, Jukka

2014-01-01

347

Temporal changes in the sensitivity of coastal Antarctic zooplankton communities to diesel fuel: a comparison between single- and multi-species toxicity tests.  

PubMed

Despite increasing human activity and risk of fuel spills in Antarctica, little is known about the impact of fuel on Antarctic marine fauna. The authors performed both single- and multi-species (whole community) acute toxicity tests to assess the sensitivity of an Antarctic coastal zooplankton community to the water-accommodated fraction of Special Antarctic Blend diesel. Single-species tests using abundant copepods Oncaea curvata, Oithona similis, and Stephos longipes allowed comparisons of sensitivity of key taxa and of sensitivity estimates obtained from traditional single-species and more novel multi-species tests. Special Antarctic Blend diesel caused significant mortality and species compositional change in the zooplankton community within 4 d to 7 d. The sensitivity of the community also increased across the summer sampling period, with decreasing 7-d median lethal concentration (LC50) values for total petroleum hydrocarbons (TPH): 1091 µg TPH/L in early January 2011, 353 µg TPH/L in mid January 2011, and 186 µg TPH/L in early February 2011. Copepods showed similar sensitivities to Special Antarctic Blend diesel in single-species tests (7-d LC50s: O. curvata, 158 µg TPH/L; O. similis, 176 µg TPH/L; S. longipes, 188 µg TPH/L). The combined use of single- and multi-species toxicity tests is a holistic approach to assessing the sensitivity of key species and the interactions and interdependence between species, enabling a broader understanding of the effects of fuel exposure on the whole zooplankton community. PMID:24590679

Payne, Sarah J; King, Catherine K; Zamora, Lara Marcus; Virtue, Patti

2014-04-01

348

Seasonal spatial pattern and community structure of zooplankton in waters off the Baleares archipelago (Central Western Mediterranean)  

NASA Astrophysics Data System (ADS)

We investigated the zooplankton community in two different areas of the Baleares Archipelago, Western Mediterranean, using data obtained in autumn (December 2009) and summer (July 2010). Micrometazooplankton and mesozooplankton samples were collected in the 0-200 m layer above the shelf (200 m) and the slope (900 m) of each area by a 53 ?m and a 200 ?m mesh size net respectively. The zooplankton biomass (expressed as dry weight) was higher in autumn than in summer (9.30 and 6.95 mg m- 3, respectively) with an important contribution of micrometazooplankters (29% and 41% of total biomass respectively). The latter fraction overwhelmed in the entire metazooplankton abundance, suggesting a non-negligible role as potential food for fish in the epipelagic waters of the Baleares archipelago. The abundance of micrometazooplankton was two-fold higher in December (3581 ind. m- 3) than in July (1585 ind. m- 3), represented mainly by small copepods and nauplii. Likewise, the mesozooplankton community showed smaller difference between months (554 and 390 ind. m- 3, in December and July). Micrometazooplankton abundance was higher in the northern area than in the southern area during autumn, probably linked to the presence of a front, while the opposite was found in summer. In both periods and areas copepods dominated, and within the highly diverse community ten species and their juveniles accounted for 70% of the community. In both areas, Clausocalanus (C. pergens + paululus and C. arcuicornis), Paracalanus parvus, Oncaea media, Oithona plumifera and Acartia clausi were abundant in autumn, whereas Centropages typicus, Temora stylifera and Mecynocera clausi were mainly present in summer. ANOSIM analysis revealed significant differences in the mesozooplankton community composition between months while differences between areas were detected only in summer.

Fernández de Puelles, M. L.; Macias, V.; Vicente, L.; Molinero, J. C.

2014-10-01

349

Mesozooplankton community development at elevated CO2 concentrations: results from a mesocosm experiment in an Arctic fjord  

NASA Astrophysics Data System (ADS)

The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world ocean. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated CO2 are still lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 ?atm to 1420 ?atm. Vertical net hauls were taken weekly over about one month with an Apstein net (55 ?m mesh size) in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analysed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (Cirripedia, Polychaeta, Bivalvia, Gastropoda, and Decapoda) dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica) were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms and the pCO2 had no significant effect on the overall community structure. Also, we did not find significant relationships between the pCO2 level and the abundance of single taxa. Changes in heterogeneous communities are, however, difficult to detect, and the exposure to elevated pCO2 was relatively short. We therefore suggest that future mesocosm experiments should be run for longer periods.

Niehoff, B.; Schmithüsen, T.; Knüppel, N.; Daase, M.; Czerny, J.; Boxhammer, T.

2013-03-01

350

Comparison between zooplankton data collected by the Continuous Plankton Recorder survey in the English Channel and by WP-2 nets at station L4, Plymouth (UK)  

NASA Astrophysics Data System (ADS)

Zooplankton sampling has been carried out by the Continuous Plankton Recorder (CPR) survey since the 1930s enabling the study of long-term changes in plankton populations, the elucidation of seasonal patterns of abundance, and more recently providing zooplankton biomass estimates for ecosystem models. Data for zooplankton abundance collected by CPR tows in the Western English Channel (between 1988 and 1998) were compared to vertically integrated samples collected from station L4 off Plymouth, UK. Comparisons were made for locally abundant copepods (including Acartia, Calanus, Para/ Pseudocalanus, Centropages, Oithona and Temora) collected by CPR and WP-2 nets. All dominant species recorded at L4 were also common to the CPR data. However, the position of the taxa in the two datasets was not equivalent. Seasonal cycles revealed by CPR data were significantly similar to those recorded throughout the water column at L4 for most taxa. However, absolute levels of abundance differed for the two datasets: abundances were underestimated by CPR samples when compared to those of vertically integrated samples by a factor of between 2 and 35, with the exception of Centropages. The differing mesh sizes (200 and 270 ?m) of the WP-2 net and CPR mesh could only partially explain these differences in abundance, implying that the behaviour of individual taxa and their depth in the water column also influenced the abundance recorded.

John, Eurgain H.; Batten, Sonia D.; Harris, Roger P.; Hays, Graeme C.

2001-12-01

351

Mesozooplankton community seasonal succession and its drivers: Insights from a British Columbia, Canada, fjord  

NASA Astrophysics Data System (ADS)

The mesozooplankton dynamics in Rivers Inlet, a fjord in Central British Columbia, Canada, were studied from March to June of 2008, 2009 and 2010 to assess the interannual, seasonal, and spatial variability in zooplankton abundance and community structure under different physical environments and spring bloom scenarios. Samples were collected fortnightly during 2008-2009 and monthly in 2010 and provide one of the few multi-year zooplankton time series in the region. Two distinct zooplankton communities characterized the observed succession pattern. The winter-spring group was described by the presence of small, year-round omnivorous zooplankton: bryozoan cyphonautes, Microcalanus spp., Microsetella spp., Oithona spp., and Oncaea spp., as well as by large, diapausing copepods such as Eucalanus bungii, Neocalanus plumchrus, and Calanus marshallae and the euphausiids Thysanoessa spinifera. By contrast, the spring-summer community showed an increased abundance of Acartia longiremis, cladocerans, Limacina helicina, Metridia pacifica, Euphausia pacifica, appendicularians, Clione limacina, chaetognaths, polychaetes, Pseudocalanus spp., ostracods, and amphipods. The timing of zooplankton succession was consistently associated with the timing of the spring bloom, and was delayed in 2009 when the spring bloom occurred in May rather than April. The zooplankton succession dynamics are discussed in terms of dominant feeding guild structure to highlight the potential mechanisms of succession. Spatial variability in zooplankton distribution was mainly influenced by river flow and exchanges with adjacent coastal waters.

Tommasi, Désirée; Hunt, Brian P. V.; Pakhomov, Evgeny A.; Mackas, Dave L.

2013-04-01

352

The distribution and vertical flux of fecal pellets from large zooplankton in Monterey bay and coastal California  

NASA Astrophysics Data System (ADS)

We sampled zooplankton and fecal pellets in the upper 200 m of Monterey Bay and nearby coastal regions in California, USA. On several occasions, we observed high concentrations of large pellets that appeared to be produced during night-time by dielly migrating euphausiids. High concentrations of pellets were found in near-surface waters only when euphausiids co-occurred with high concentrations of large (>10 ?m) phytoplankton. Peak concentrations of pellets at mid-depth (100 or 150 m) during the day were consistent with the calculated sinking speeds of pellets produced near the surface at night. At these high flux locations (HI group), pellet concentrations declined below mid-depth. In contrast, at locations where the phytoplankton assemblage was dominated by small phytoplankton cells (<10 ?m), pellet production and flux were low (LO group) whether or not euphausiid populations were high. Protozooplankton concentrations did not affect this pattern. We concluded that the day and night differences in pellet concentration and flux in the HI profiles were mostly due to sinking of dielly-pulsed inputs in the surface layer, and that small zooplankton (Oithona, Oncaea), heterotrophic dinoflagellates, and bacterial activity probably caused some pellet degradation or consumption below 100 m. We estimated that consumption of sinking pellets by large copepods was insignificant. High fluxes of pellets were episodic because they required both high concentrations of large phytoplankton and large stocks of euphausiids. Under these conditions, flux events overwhelmed retention mechanisms, resulting in large exports of organic matter from the upper 200 m.

Dagg, Michael J.; Jackson, George A.; Checkley, David M.

2014-12-01

353

Responses of seabirds, in particular prions ( Pachyptila sp.), to small-scale processes in the Antarctic Polar Front  

NASA Astrophysics Data System (ADS)

Small-scale distribution patterns of seabirds in the Antarctic Polar Front (APF) were investigated in relation to other biological, physical, and chemical features during the ANT-XIII/2 research cruise of R.V. Polarstern from December 1995 to January 1996. The APF is characterized by steep gradients in sea-surface temperature and salinity. Within the APF, gradient zones were closely associated with elevated levels of primary production, chlorophyll- a (chl- a) concentrations, and zooplankton densities. Even broad-billed prions (' Pachyptila vittata-group'), which dominated the seabird community by 83% in carbon requirements, showed small-scale distributional patterns that were positively related to primary production, chl- a, and total zooplankton densities. The findings demonstrate a close, direct link between fine-scale physical processes in the APF and biological activity through several food web levels up to that of zooplankton-eating seabirds. Broad-billed prions appeared to forage on very small copepods ( Oithona spp.) in close association with the front. Fish- and squid-eating predators showed poor correlations with small-scale spatial structures of the APF. However, in a wider band around the APF, most top predators did occur in elevated densities, showing gradual spatio-temporal diffusion of the impact of the APF on higher trophic levels.

van Franeker, Jan A.; van den Brink, Nico W.; Bathmann, Ulrich V.; Pollard, Raymond T.; de Baar, Hein J. W.; Wolff, Wim J.

354

Crustacea in Arctic and Antarctic sea ice: distribution, diet and life history strategies.  

PubMed

This review concerns crustaceans that associate with sea ice. Particular emphasis is placed on comparing and contrasting the Arctic and Antarctic sea ice habitats, and the subsequent influence of these environments on the life history strategies of the crustacean fauna. Sea ice is the dominant feature of both polar marine ecosystems, playing a central role in physical processes and providing an essential habitat for organisms ranging in size from viruses to whales. Similarities between the Arctic and Antarctic marine ecosystems include variable cover of sea ice over an annual cycle, a light regimen that can extend from months of total darkness to months of continuous light and a pronounced seasonality in primary production. Although there are many similarities, there are also major differences between the two regions: The Antarctic experiences greater seasonal change in its sea ice extent, much of the ice is over very deep water and more than 80% breaks out each year. In contrast, Arctic sea ice often covers comparatively shallow water, doubles in its extent on an annual cycle and the ice may persist for several decades. Crustaceans, particularly copepods and amphipods, are abundant in the sea ice zone at both poles, either living within the brine channel system of the ice-crystal matrix or inhabiting the ice-water interface. Many species associate with ice for only a part of their life cycle, while others appear entirely dependent upon it for reproduction and development. Although similarities exist between the two faunas, many differences are emerging. Most notable are the much higher abundance and biomass of Antarctic copepods, the dominance of the Antarctic sea ice copepod fauna by calanoids, the high euphausiid biomass in Southern Ocean waters and the lack of any species that appear fully dependent on the ice. In the Arctic, the ice-associated fauna is dominated by amphipods. Calanoid copepods are not tightly associated with the ice, while harpacticoids and cyclopoids are abundant. Euphausiids are nearly absent from the high Arctic. Life history strategies are variable, although reproductive cycles and life spans are generally longer than those for temperate congeners. Species at both poles tend to be opportunistic feeders and periods of diapause or other reductions in metabolic expenditure are not uncommon. PMID:16905428

Arndt, Carolin E; Swadling, Kerrie M

2006-01-01

355

Grazing by meso- and microzooplankton on phytoplankton in the upper reaches of the Schelde estuary (Belgium/The Netherlands)  

NASA Astrophysics Data System (ADS)

In contrast with the marine reaches of estuaries, few studies have dealt with zooplankton grazing on phytoplankton in the upper estuarine reaches, where freshwater zooplankton species tend to dominate the zooplankton community. In spring and early summer 2003, grazing by micro- and mesozooplankton on phytoplankton was investigated at three sites in the upper Schelde estuary. Grazing by mesozooplankton was evaluated by monitoring growth of phytoplankton in 200 ?m filtered water in the presence or absence of mesozooplankton. In different experiments, the grazing impact was tested of the calanoïd copepod Eurytemora affinis, the cyclopoid copepods Acanthocyclops robustus and Cyclops vicinus and the cladocera Chydorus sphaericus, Moina affinis and Daphnia magna/ pulex. No significant grazing impact of mesozooplankton in any experiment was found despite the fact that mesozooplankton densities used in the experiments (20 or 40 ind. l -1) were higher than densities in the field (0.1-6.9 ind. l -1). Grazing by microzooplankton was evaluated by comparing growth of phytoplankton in 30 and 200 ?m filtered water. Microzooplankton in the 30-200 ?m size range included mainly rotifers of the genera Brachionus, Trichocerca and Synchaeta, which were present from 191 to 1777 ind. l -1. Microzooplankton had a significant grazing impact in five out of six experiments. They had a community grazing rate of 0.41-1.83 day -1 and grazed up to 84% of initial phytoplankton standing stock per day. Rotifer clearance rates estimated from microzooplankton community grazing rates and rotifer abundances varied from 8.3 to 41.7 ?l ind. -1 h -1. CHEMTAX analysis of accessory pigment data revealed a similar phytoplankton community composition after incubation with and without microzooplankton, indicating non-selective feeding by rotifers on phytoplankton.

Lionard, M.; Azémar, F.; Boulêtreau, S.; Muylaert, K.; Tackx, M.; Vyverman, W.

2005-09-01

356

Directional Darwinian Selection in proteins  

PubMed Central

Background Molecular evolution is a very active field of research, with several complementary approaches, including dN/dS, HON90, MM01, and others. Each has documented strengths and weaknesses, and no one approach provides a clear picture of how natural selection works at the molecular level. The purpose of this work is to present a simple new method that uses quantitative amino acid properties to identify and characterize directional selection in proteins. Methods Inferred amino acid replacements are viewed through the prism of a single physicochemical property to determine the amount and direction of change caused by each replacement. This allows the calculation of the probability that the mean change in the single property associated with the amino acid replacements is equal to zero (H0: ? = 0; i.e., no net change) using a simple two-tailed t-test. Results Example data from calanoid and cyclopoid copepod cytochrome oxidase subunit I sequence pairs are presented to demonstrate how directional selection may be linked to major shifts in adaptive zones, and that convergent evolution at the whole organism level may be the result of convergent protein adaptations. Conclusions Rather than replace previous methods, this new method further complements existing methods to provide a holistic glimpse of how natural selection shapes protein structure and function over evolutionary time. PMID:24267049

2013-01-01

357

Impacts of Wolbachia infection on predator prey relationships: evaluating survival and horizontal transfer between wMelPop infected Aedes aegypti and its predators.  

PubMed

The wMelPop strain of Wolbachia is currently being investigated for its potential use as a biological control agent to reduce the ability of Aedes aegypti (L.) mosquitoes to transmit dengue viruses. The survival of a potential wMelPop infected Ae. aegypti strain for field release is important as a higher susceptibility to predation in the wMelPop strain could result in difficulties in achieving fixation. We investigated immature and adult survival as a function of susceptibility to predation by six naturally occurring predator species; cyclopoid copepods, fish, predatory Toxorhynchites mosquito larvae and a salticid jumping spider. The trials indicated that wMelPop infected and uninfected Ae. aegypti larvae and adults were equally susceptible to predation to all six tested predators. In addition to evaluating any potential fitness costs to the infected host, we were unable to demonstrate horizontal transfer of wMelPop via consumption of infected Ae. aegypti larvae to the above predators. That susceptibility to predation was consistent across mosquito life stage, predator species and experimental venue is strong evidence that despite the neurotrophic and extensive nature of wMelPop infection, behavioral changes are not occurring, or at least not a determining factor in survival when exposed to a predator. Based on our results and the ecology of Wolbachia and mosquito predators, horizontal transfer of wMelPop from Ae. aegypti into naturally occurring predators is not cause for concern. PMID:22679870

Hurst, Timothy P; Pittman, Geoff; O'Neill, Scott L; Ryan, Peter A; Nguyen, Hoang Le; Kay, Brian H

2012-05-01

358

Diet overlap in larval lake herring (Coregonus artedi) and bloaters (Coregonus hoyi)  

USGS Publications Warehouse

The food preferences of larval lake herring (Coregonus artedi) and bloater (C.hoyi) were compared in a small mesotrophic lake in southeastern Michigan. Diets of the two were increasingly similar as the experiment progressed until, by the end of 6.5 weeks, they were identical; Schoener's Index of diet overlap averaged 0.35 in the first week and reached 0.96 by the end of the study. In the first few weeks, lake herring ate mostly small cladocerans (Bosmia longirostris) and bloaters ate mostly large cladocerans (Eurycercus lamellatus). Strauss's selection index confirmed that lake herring actively fed on small cladocerans throughout the study and that bloaters relied more on cyclopoid copepods during the early part of the study and shifted to eating small and large cladocerans by the end. Both species had similar growth rates throughout the study and amount of consumed food was identical. The diet similarities of lake herring and bloater larvae could make them competitors for food in the Great Lakes, relieved only by a dissimilarity in hatching times and locations.

Davis, Bruce M.; Todd, Thomas N.

1992-01-01

359

Polymethylene-interrupted fatty acids: Biomarkers for native and exotic mussels in the Laurentian Great Lakes  

USGS Publications Warehouse

Freshwater organisms synthesize a wide variety of fatty acids (FAs); however, the ability to synthesize and/or subsequently modify a particular FA is not universal, making it possible to use certain FAs as biomarkers. Herein we document the occurrence of unusual FAs (polymethylene-interrupted fatty acids; PMI-FAs) in select freshwater organisms in the Laurentian Great Lakes. We did not detect PMI-FAs in: (a) natural seston from Lake Erie and Hamilton Harbor (Lake Ontario), (b) various species of laboratory-cultured algae including a green alga (Scenedesmus obliquus), two cyanobacteria (Aphanizomenon flos-aquae and Synechococystis sp.), two diatoms (Asterionella formosa, Diatoma elongatum) and a chrysophyte (Dinobryon cylindricum) or, (c) zooplankton (Daphnia spp., calanoid or cyclopoid copepods) from Lake Ontario, suggesting that PMI-FAs are not substantively incorporated into consumers at the phytoplankton–zooplankton interface. However, these unusual FAs comprised 4-6% of total fatty acids (on a dry tissue weight basis) of native fat mucket (Lampsilis siliquoidea) and plain pocketbook (L. cardium) mussels and in invasive zebra (Dreissena polymorpha) and quagga (D. bugensis) mussels. We were able to clearly partition Great Lakes' mussels into three separate groups (zebra, quagga, and native mussels) based solely on their PMI-FA profiles. We also provide evidence for the trophic transfer of PMI-FAs from mussels to various fishes in Lakes Ontario and Michigan, further underlining the potential usefulness of PMI-FAs for tracking the dietary contribution of mollusks in food web and contaminant-fate studies.

Mezek, Tadej; Sverko, Ed; Ruddy, Martina D.; Zaruk, Donna; Capretta, Alfredo; Hebert, Craig E.; Fisk, Aaron T.; McGoldrick, Daryl J.; Newton, Teresa J.; Sutton, Trent M.; Koops, Marten A.; Muir, Andrew M.; Johnson, Timothy B.; Ebener, Mark P.; Arts, Michael T.

2011-01-01

360

A new species of Metacyclops Kiefer, 1927 (Copepoda, Cyclopidae, Cyclopinae) from the Chihuahuan desert, northern Mexico  

PubMed Central

Abstract A new species of the freshwater cyclopoid copepod genus Metacyclops Kiefer, 1927 is described from a single pond in northern Mexico, within the binational area known as the Chihuahuan Desert. This species belongs to a group of Metacyclops species with a 3443 spine formula of swimming legs. It is morphologically similar to Metacyclops lusitanus Lindberg, 1961 but differs from this and other congeners by having a unique combination of characters, including a caudal rami length/width proportion of 3.5–3.8, a innermost terminal seta slightly longer than the outermost terminal seta, intercoxal sclerites of legs 1-4 naked, a strong apical spine of the second endopodal segment of leg 1 and one row of 6-8 small spinules at the insertion of this spine. The finding of this species represents also the first record of the genus in Mexico and the third in North America, where only two other species, Metacyclops gracilis (Lilljeborg, 1853)and Metacyclops cushae Reid, 1991 have been hitherto reported. This is also the first continental record of a species of Metacyclops from an arid environment in the Americas. This species appears to be endemic to the Chihuahuan Desert, thus emphasizing the high endemicity of this area. PMID:23794845

Mercado-Salas, Nancy F.; Suárez-Morales, Eduardo; Maeda-Martínez, Alejandro M.; Silva-Briano, Marcelo

2013-01-01

361

[Spatiotemporal characteristics of zooplankton community structure and diversity in the strong temperature increment seawaters near Guohua power plant in Xiangshan Bay].  

PubMed

To explore the spatiotemporal characteristics of the zooplankton community structure and diversity in the strong temperature increment seawaters near a power plant, zooplankton samples were seasonally collected in duplicate by the type II net with mesh size of 160 microm at 10 stations near Guohua power plant in Xiangshan Bay in 2011. The results showed that a total of 62 species (including larvae) were identified in the samples, and the average abundance was 9 531.1 ind x m(-3). In the seawaters, zooplankton communities were mainly composed of copepods and pelagic larvae, and pelagic larvae were the dominant with an average percentage of abundance reached up to 66.6%. Analysis of similarities demonstrated that significant differences existed in zooplankton community structures among different months (P < 0.01). In these zooplankton communities, there were 18 dominant species controlling these community structures, among which the most important discriminating species were Centropages tenuiremis, Oithona similis, Oithona fallax, Acartia clausi, Clausocalanus furcatus, Paracalanus aculeatus and Paracalanus parvwus. GLM analysis indicated that diversity indices were also significantly different among different months (P < 0.01). According to the calculation results, the inflection point, where the diversity index began to decrease with increasing water temperature, fell within 20.31-22.31 degrees C. In sections, the average water temperature in the 0.2 km section (D02), away from the outfall, was 2.16: higher than that in the 2 km section. Driven by temperature, the main dominant species such as C. tenuiremis and O. similis tended to move into the 0.2 km section, while A. clause and especially large zooplankton tended to stay away from the outfall, and then gathered in the 1.2 km section. As a result, the number of species (33 species) and abundance (5 522.8 ind x m(-3)) were minimum in the section D02, while the number of species (53 species) and abundance (16 491.0 ind x m(-3)) reached the highest in the 1.2 km section. Meanwhile, diversity indices in the 0.2 km section were also obviously lower than those in other sections. Linear regression analysis showed that the diversity indices significantly decreased with increasing water temperature (P < 0.01). The zooplankton richness decreased by 12.3% when the water temperature increased by 1 degrees C. PMID:23798135

Zhu, Yi-Feng; Huang, Jian-Yi; Lin, Xia; Yang, Ying; Xing, Chao; Yan, Xiao-Jun

2013-04-01

362

The nearshore zone during coastal upwelling: Daily variability and coupling between primary and secondary production off central Chile  

NASA Astrophysics Data System (ADS)

The nearshore region of central Chile is important for spawning of sardine ( Sardinops sagax) anchovy ( Engraulis ringens) and jack mackerel ( Trachurus murphyii) and the importance of fisheries for these species has led to an interest in factors controlling the area's productivity. We studied daily variations in productivity at a nearshore station (25m depth) off Dichato, Chile (36°30?S) during January 1986 to understand how wind-driven variability in the hydrography is translated into pulses of primary and secondary production of the plankton. During the study period, we observed three complete cycles of upwelling favourable/unfavourable winds. Water column destratification, as indicated by the surface-to-bottom gradient of sigma-t, lagged the wind by about one day. During active upwelling, cold water (<11.5°C) of high nitrate and low oxygen concentration (20-25?M and 1-2ml 1 -1 respectively) was found near the surface. During subsequent relaxation of upwelling, the water column became stratified as temperature, oxygen and chlorophyll increased. The size and taxonomic composition of the phytoplankton varied from one event to the next. Over the course of the study, from 15-100% of the chlorophyll could pass a 20?m mesh screen. Chain-forming diatoms, microflagellates, and the autotrophic ciliate Mesodinium rubrum dominated the first, second and third events, respectively. In rank order of abundance, Paracalanus parvus, Centropages brachiatus, Oithona spp., Acartia tonsa, Oncaea spp., Calanoides patagoniensis and Calanus chilensis dominated the copepod community. Changes in abundance of most species did not closely follow the upwelling cycle. Possibly, vertical movements or other behavioural responses caused zooplankton distributions to be uncorrelated with movements of the surface Ekman layer. Fecundity of several of the important copepod species was measured using the egg ratio and bottle incubation techniques. Compared to values reported in the literature, egg production was usually suboptimal, despite high nutritional quality of the phytoplankton, as indicated by protein/carbohydrate ratios. Food availability, due to either small phytoplankton size or spatial and temporal uncoupling of phyto- and zooplankton populations, was probably most important in limiting copepod production. Event-scale advection, both zonal and alongshore, can be important in uncoupling primary and secondary production and probably determines the degree to which upwelling-generated pulses of phytoplankton production are utilized by herbivorous plankton in the nearshore zone.

Peterson, William T.; Arcos, Dagoberto F.; McManus, George B.; Dam, Hans; Bellantoni, Diane; Johnson, Thomas; Tiselius, Peter

363

Zooplankton species composition, abundance and biomass on the eastern Bering Sea shelf during summer: The potential role of water-column stability and nutrients in structuring the zooplankton community  

NASA Astrophysics Data System (ADS)

The southeastern Bering Sea sustains one of the largest fisheries in the United States, as well as wildlife resources that support valuable tourist and subsistence economies. The fish and wildlife populations in turn are sustained by a food web linking primary producers to apex predators through the zooplankton community. Recent shifts in climate toward warmer conditions may threaten these resources by altering productivity and trophic relationships in the ecosystem on the southeastern Bering Sea shelf. We examined the zooplankton community near the Pribilof Islands and on the middle shelf of the southeastern Bering Sea in summer of 1999 and 2004 to document differences and similarities in species composition, abundance and biomass by region and year. Between August 1999 and August 2004, the summer zooplankton community of the middle shelf shifted from large to small species. Significant declines were observed in the biomass of large scyphozoans ( Chrysaora melanaster), large copepods ( Calanus marshallae), arrow worms ( Sagitta elegans) and euphausiids ( Thysanoessa raschii, T. inermis) between 1999 and 2004. In contrast, significantly higher densities of the small copepods ( Pseudocalanus spp., Oithona similis) and small hydromedusae ( Euphysa flammea) were observed in 2004 relative to 1999. Stomach analyses of young-of-the-year (age 0) pollock ( Theragra chalcogramma) from the middle shelf indicated a dietary shift from large to small copepods in 2004 relative to 1999. The shift in the zooplankton community was accompanied by a 3-fold increase in water-column stability in 2004 relative to 1999, primarily due to warmer water above the thermocline, with a mean temperature of 7.3 °C in 1999 and 12.6 °C in 2004. The elevated water-column stability and warmer conditions may have influenced the zooplankton composition by lowering summer primary production and selecting for species more tolerant of a warm, oligotrophic environment. A time series of temperature from the middle shelf indicates that the warmer conditions in 2004 are part of a trend rather than an expression of interannual variability. These results suggest that if climate on the Bering Sea shelf continues to warm, the zooplankton community may shift from large to small taxa which could strongly impact apex predators and the economies they support.

Coyle, Kenneth O.; Pinchuk, Alexei I.; Eisner, Lisa B.; Napp, Jeffrey M.

2008-08-01

364

Endemism of subterranean Diacyclops in Korea and Japan, with descriptions of seven new species of the languidoides-group and redescriptions of D. brevifurcus Ishida, 2006 and D. suoensis Ito, 1954 (Crustacea, Copepoda, Cyclopoida)  

PubMed Central

Abstract Copepods have been poorly studied in subterranean habitats in Korea. Previous records have indicated mostly the presence of species already described from Japan, with very few endemic elements. This commonality has usually been explained by repeated dispersal across the land bridges that connected the two countries several times during the Pleistocene glacial cycles. However, the Korean Peninsula is known for pockets of Cambrian and Ordovician carbonate rocks, with more than 1,000 caves already having been explored. The relative isolation of these carbonate pockets makes for an enormous speciation potential, and the development of a high level of short-range endemism of subterranean copepods should be expected. Representatives of the genus Diacyclops Kiefer, 1927 are here investigated from a range of subterranean habitats in South Korea, with comparative material sampled from central Honshu in Japan. Morphological analyses of microcharacters, many of which are used in cyclopoid taxonomy for the first time herein, reveal high diversity in both countries. No subterranean species is found in common, although the existence of four sibling species pairs in Korea and Japan may be indicative of relatively recent speciation. We describe seven new stygobiotic species, including three from Korea (Diacyclops hanguk sp. n., Diacyclops leeae sp. n., and Diacyclops parasuoensis sp. n.) and four from Japan (Diacyclops hisuta sp. n., Diacyclops ishidai sp. n., Diacyclops parahanguk sp. n., and Diacyclops pseudosuoensis sp. n.). Diacyclops hanguk, Diacyclops parasuoensis, Diacyclops ishidai, and Diacyclops parahanguk are described from newly collected material, while the other three new species are proposed for specimens previously identified as other, widely distributed species. Diacyclops brevifurcus Ishida, 2006 is redescribed from the holotype female, and Diacyclops suoensis Ito, 1954 is redescribed from material newly collected near the ancient Lake Biwa in Japan. This research provides evidence for the importance of subterranean habitats as reservoirs of biodiversity, and also demonstrates the inadequacy of current morphological methods of identifying closely related species of copepods. The disproportionately high diversity discovered around Lake Biwa provides further evidence in support of the hypothesis about the role of ancient lakes as biodiversity pumps for subterranean habitats. A key to the East Asian species of the languidoides-group is provided. PMID:23653520

Karanovic, Tomislav; Grygier, Mark J.; Lee, Wonchoel

2013-01-01

365

Studies on harpacticoid copepod populations of two transects across the south Texas outer continental shelf  

E-print Network

ot all species ali hough it bias ound at only one stati or. . Ha7. eef:L1' aomQ 8'i!vlf 7fdfa- f no. ':uvi Lang '. 'as the second iaost. abundant species found, being sliuh!, ly domiI;ant at one station and occurring at six of twenty-six poss... refer- ences: Lang (1948, 1965), Iiells (1967, 1976), Por (1959, 1964a. , b;, I'loodi, (1964), Coull (1973b, 1975, 1976, 1977), Coull and Bogue (1978), Dinet (1971), Geddes (1968a), Harrrond (1971, 1973a, b, c, d), Klie {1949), Kunz {1962), Brcker (1...

Venn, Cynthia

2012-06-07

366

Variation in Body Shape across Species and Populations in a Radiation of Diaptomid Copepods  

PubMed Central

Inter and intra-population variation in morphological traits, such as body size and shape, provides important insights into the ecological importance of individual natural populations. The radiation of Diaptomid species (~400 species) has apparently produced little morphological differentiation other than those in secondary sexual characteristics, suggesting sexual, rather than ecological, selection has driven speciation. This evolutionary history suggests that species, and conspecific populations, would be ecologically redundant but recent work found contrasting ecosystem effects among both species and populations. This study provides the first quantification of shape variation among species, populations, and/or sexes (beyond taxonomic illustrations and body size measurements) to gain insight into the ecological differentiation of Diaptomids. Here we quantify the shape of five Diaptomid species (family Diaptomidae) from four populations each, using morphometric landmarks on the prosome, urosome, and antennae. We partition morphological variation among species, populations, and sexes, and test for phenotype-by-environment correlations to reveal possible functional consequences of shape variation. We found that intraspecific variation was 18-35% as large as interspecific variation across all measured traits. Interspecific variation in body size and relative antennae length, the two traits showing significant sexual dimorphism, were correlated with lake size and geographic location suggesting some niche differentiation between species. Observed relationships between intraspecific morphological variation and the environment suggest that divergent selection in contrasting lakes might contribute to shape differences among local populations, but confirming this requires further analyses. Our results show that although Diaptomid species differ in their reproductive traits, they also differ in other morphological traits that might indicate ecological differences among species and populations. PMID:23826384

Hausch, Stephen; Shurin, Jonathan B.; Matthews, Blake

2013-01-01

367

The reproductive cycle and life history of the Arctic copepod Calanus glacialis in the White Sea  

Microsoft Academic Search

Seasonal variations in the gonad development and sex ratio of copepodite stage V (CV) and adults were examined from February\\u000a to November in order to understand the reproductive cycle and the life history of Calanus glacialis in the White Sea. Gonad maturation, sexual differentiation and moulting to adults take place during the 2nd year of development.\\u000a Energy accumulation takes place

K. N. Kosobokova

1999-01-01

368

Tech Copepod aggregations at oceanographic discontinuities Sponsor: Office of Naval Research  

E-print Network

Research NSF-IGERT Program, Signals in the Sea Faculty: Dr. Donald R. Webster Dr. Marc J. Weissburg, School associated with structure in the ocean. Limnol. Oceanogr. to appear. Woodson, C. B., D. R. Webster, M. J of a behavior known as area- restricted searching. By altering swimming patterns (speed and turning; see table

369

Uptake and elimination, and effect of estrogen-like contaminants in estuarine copepods: an experimental study  

Microsoft Academic Search

Background, aim, and scope  In recent years, anthropogenic chemicals which can disrupt the hormonal systems of both humans and wildlife have been raised\\u000a to a major cause of concern. The aim of the present work was to determine the bioconcentration factors of the two major alkylphenols\\u000a (AP) of the Seine Estuary [4-nonylphenol (4 NP) and nonylphenol acetic acid (NP1EC)] and of

Kevin Cailleaud; Hélène Budzinski; Sophie Lardy; Sylvie Augagneur; Sabria Barka; Sami Souissi; Joëlle Forget-Leray

2011-01-01

370

EFFECT OF HUMIC ACID ON UPTAKE AND TRANSFER OF COPPER FROM MICROBES TO CILIATES TO COPEPODS  

EPA Science Inventory

This research is part of an ongoing project designed to determine the effect of humic acid on the uptake and transfer of metals by marine organisms at the lower end of the food chain. Binding affinities for Cu, Cd, Zn, and Cr to Suwannee River humic acid were determined at variou...

371

FIPRONIL-INDUCED MALE INFERTILITY IN THE MEIOBENTHIC HARPACTICOID COPEPOD, AMPHIASCUS TENUIREMIS. (R827397)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

372

VECTORIAL TRANSPORT OF TOXINS FROM THE DINOFLAGELLATE GYMNODINIUM BREVE THROUGH COPEPODS TO FISH. (R827085)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

373

LIFE-HISTORY VARIATION IN THE COEXISTING FRESHWATER COPEPODS EUDIAPTOMUS GRACILIS AND EUDIAPTOMUS GRACILOIDES. (R824771)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

374

Acute and sub-lethal response to mercury in Arctic and boreal calanoid copepods.  

PubMed

Acute lethal toxicity, expressed as LC50 values, is a widely used parameter in risk assessment of chemicals, and has been proposed as a tool to assess differences in species sensitivities to chemicals between climatic regions. Arctic Calanus glacialis and boreal Calanus finmarchicus were exposed to mercury (Hg(2+)) under natural environmental conditions including sea temperatures of 2° and 10°C, respectively. Acute lethal toxicity (96 h LC50) and sub-lethal molecular response (GST expression; in this article gene expression is used as a synonym of gene transcription, although it is acknowledged that gene expression is also regulated, e.g., at translation and protein stability level) were studied. The acute lethal toxicity was monitored for 96 h using seven different Hg concentrations. The sub-lethal experiment was set up on the basis of nominal LC50 values for each species using concentrations equivalent to 50, 5 and 0.5% of their 96 h LC50 value. No significant differences were found in acute lethal toxicity between the two species. The sub-lethal molecular response revealed large differences both in response time and the fold induction of GST, where the Arctic species responded both faster and with higher mRNA levels of GST after 48 h exposure. Under the natural exposure conditions applied in the present study, the Arctic species C. glacialis may potentially be more susceptible to mercury exposure on the sub-lethal level. PMID:25036619

Overjordet, Ida Beathe; Altin, Dag; Berg, Torunn; Jenssen, Bjørn Munro; Gabrielsen, Geir Wing; Hansen, Bjørn Henrik

2014-10-01

375

COPEPOD REPRODUCTIVE STRATEGIES: LIFE-HISTORY THEORY, PHYLOGENETIC PATTERN AND INVASION OF INLAND WATERS. (R824771)  

EPA Science Inventory

Abstract Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven ...

376

Calanoid copepods of the genus Heterorhabdus Giesbrecht 1898 from the Gulf of Mexico  

E-print Network

posterior to large genital valve. Dorsal profile medially concave posterior to slight anterior swelling (Fig. 4F). Caudal rami asymmetrical, left ramus being larger (Fig. 4A). Description, male. --Total body length ranging 2. 80-3. 16 mm, mean length 2..., genital segment. with symmetrically rounded sides (Fig. 8A) . In lateral view, genital swelling with large ventral valve. Dorsal profile swollen anteriorly (Fig. BF). Caudal rami markedly asymmetrical, left ramus being larger (Fig. BA). Description...

Boerwinkle, William Robert

2012-06-07

377

A preliminary study of the distribution of some copepods in upper Laguna Madre  

E-print Network

31 47 57 67 77 97 A. tonsa 0. brev'cornis Other Total A . tonsa 0. brev'cornis Ot;her . otal tones 0, brevtcornis Other Total A. tonsa 0. brevi. cornis Other Total A. t;onsa 0. brevicor nis Other Tots~ A. tonsa 0. brevicornis... 31 47 57 67 77 97 A. tonsa 0. brev'cornis Other Total A . tonsa 0. brev'cornis Ot;her . otal tones 0, brevtcornis Other Total A. tonsa 0. brevi. cornis Other Total A. t;onsa 0. brevicor nis Other Tots~ A. tonsa 0. brevicornis...

Henderson, John C

2012-06-07

378

Effects of constant and intermittent food supply on life-history parameters in a marine copepod  

Microsoft Academic Search

Laboratory experiments were used to determine effects of long- and short-term food limitation on birth, growth, and death rates in Centropages typicus (Copepoda, Calanoida), a species previously reported to be sensitive to patchy food resources. Life-history parameters were measured in cohorts from hatching to senescence in a range of constant food treatments (0.2-7 pg Chl a liter-') and in two

CABELL S. DAVIS; PHILIP ALATALO

1992-01-01

379

Laboratory culture, growth rate, and feeding behavior of a planktonic marine copepod  

Microsoft Academic Search

ABSTRACX Rhincalnnus nasutus was cultured through scvcn consecutive generations in l%litcr carboys when provided with a mixture of diatoms and Artemia salina nauplii as food. The mean generation length was 8.7 weeks, similar to that of the local field population of this species during some seasons. Fecundity of laboratory-reared animals was lower than that of the field population. Instantaneous coefficients

MICHAEL M. MULLIN; ELAINE R. BROOKS

1967-01-01

380

Ultraviolet damage and counteracting mechanisms in the freshwater copepod Boeckella poppei from the Antarctic Peninsula  

Microsoft Academic Search

The process of ozone depletion over the Antarctic continent has resulted in the increase of incident ultraviolet- B (UVB) radiation, whose effects may be damaging to living organisms. To counteract the negative effects of ultraviolet radiation (UVR), aquatic organisms may display one or more strategies: (1) avoidance (i.e. deep distri- bution); (2) photoprotection through the use of ''sunscreen'' compounds, such

Vanina E. Rocco; Oscar Oppezzo; Ramon Pizarro; Ruben Sommaruga; Marcela Ferraro; Horacio E. Zagarese

2002-01-01

381

Copepods of Hatschekiidae (Copepoda, Siphonostomatoida) new to Korean fauna, with description of a new species  

NASA Astrophysics Data System (ADS)

Eight species of the Hatschekiidae are recorded as parasites of marine fishes from southern coast of Korea. One new species, Hatschekia jejuensis, parasitic on Cheilodactylus zonatus Cuvier is included. The remaining seven species are new to Korean fauna: Hatschekia iridescens Wilson, 1913, H. japonica Jones, 1985, H. monacanthi Yamaguti, 1939, H. tenuis (Heller, 1865) H. pseudolabri Yamaguti, 1953, H. cylindrica Shiino, 1957, and Pseudocongericola chefoonensis Yü, 1933. Hatschekia jejuensis n. sp. has a combination of characteristics in the female where the trunk is 2.35 times as long as the cephalothorax and displays a pair of posterolateral bulges on both sides, the antennules is 5-segmented, the mandible bears six teeth, and the armature formulae of the legs are I-0; III (exopod) and 0-0; II (endopod) for leg 1 and I-0; I (exopod) and 0-0; II (endopod) for leg 2.

Moon, Seong Yong; Kim, Il-Hoi

2013-03-01

382

WINTER-TIME DISTRIBUTION AND ABUNDANCE OF COPEPOD NAUPLII IN THE NORTHERN GULF OF MEXICO  

E-print Network

by the Mississippi River plumes than in the other 2 regions. This condition in attributed to vertical stratification February and December 1982, concentrations of menhaden larvae in the region near the Mississippi River the Mississippi River plumes would be regions of increased production and concentration of micro- zooplankton

383

Zooplankton responses to hypoxia: behavioral patterns and survival of three species of calanoid copepods  

Microsoft Academic Search

Seasonally recurrent and persistent hypoxic events in semi-enclosed coastal waters are characterized by bottom-water dissolved\\u000a oxygen (d.o.) concentrations of ?1. Shifts in the distribution patterns of zooplankters in association with these events have been documented, but the mechanisms\\u000a responsible for these shifts have not been investigated. This study assessed interspecific differences in responses to hypoxia\\u000a by several species of calanoid

L. C. Stalder; N. H. Marcus

1997-01-01

384

Mesoscale distribution and community composition of zooplankton in the Mozambique Channel  

NASA Astrophysics Data System (ADS)

Recent studies have shown the Mozambique Channel to exhibit high mesoscale variability, but how mesoscale features influence the zooplankton community in this region is not known. The biovolume, biomass, vertical distribution and community composition of mesozooplankton (>200 µm) associated with mesoscale eddies in the Mozambique Channel was investigated during four cruises in September 2007, December 2008, November 2009 and April/May 2010. Stations were categorized according to their location in cyclonic (cold-core) or anticyclonic (warm-core) eddies, frontal, divergence or shelf regions. Mean mesozooplankton biovolume in the upper 200 m was 0.33 ml m-3, with zooplankton largely concentrated in the upper 100 m during all four cruises (weighted mean depth=66.6 m). Sampling depth was the most important predictor of biovolume, which was greatest for net samples with a mid-depth of 0-40 m, but declined deeper in the water column. Biovolume at the shelf (0.37 ml m-3), divergence and cyclonic eddy stations (0.31 ml m-3) was significantly greater than at frontal and anticyclonic eddy stations (0.20 ml m-3). Mean biovolume was significantly higher during 2008 and 2010 compared to 2007 and 2009, and was also significantly higher for samples collected at night (and twilight) than during the day. The mesozooplankton community in 2007 was strongly dominated by small copepods (~70-80% abundance) followed by appendicularians (10%), ostracods (8%) and chaetognaths (7%). The most abundant copepods were the Paracalanids, Oncaea spp., Oithona spp. and Corycaeus spp. Multivariate analysis showed that the communities in 2007 and 2008 were most strongly structured by depth, but classification (cyclonic/anticyclonic) was also important in 2007 when mesoscale features were more strongly developed. Zooplankton assemblages showed a high degree of homogeneity, with differences between mesoscale features largely due to differing abundances of similar taxa. These observations suggest that mesoscale eddy and shelf interactions play a fundamental role in shaping the Mozambique Channel pelagic ecosystem through the concentration, enhanced growth and redistribution of zooplankton communities. Although frontal areas between eddies were poor in zooplankton biomass, the extensive inter-eddy divergence areas were as rich in biomass as the small cyclonic eddy core regions. These patterns are important for understanding the favorability of observed foraging areas for higher trophic levels.

Huggett, Jenny A.

2014-02-01

385

Pattern and persistence of a nearshore planktonic ecosystem off Southern California  

NASA Astrophysics Data System (ADS)

Three related data sets from a baseline environmental survey on the continental shelf at San Onofre, California, consisting of: (1) zooplankton pumped from discrete depths on transects between the 8- and 30-m contours, sampled from 1976 to 1980; (2) zooplankton from oblique net hauls on a transect from 8 to 100 m sampled at 2-week intervals for 1 y, 1978-1979; and (3) vertical profiles of temperature, nutrients and plant pigments corresponding closely in time and space to the oblique net hauls, are used to describe cross-shelf zooplankton abundance patterns, community composition, and seasonal and shorter-term variations in cross-shelf zonation and their relation to variations in physical and chemical measures. Of 15 taxa tested for multiyear average patterns, three—the copepods Acartia clausi and Oithona oculata, and barnacle larvae—had centers of abundance shoreward of the 30-m contour and near the bottom. No differences were detected in the cross-shelf pattern between San Onofre and a transect 12 km southeast. Throughout the year, nearshore and offshore assemblages were distinguishable, the change occurring at about the 30-m contour. The offshore one, represented by the copepods Calanus pacificus, Eucalanus californicus and Rhincalanus nasutus, occupied water having less chlorophyll and less near-surface nutrient, i.e. of more oceanic character. In spring and summer, most nearshore taxa shifted slightly seaward, leaving a third assemblage, characterized by a very high abundance of Acartia spp. copepodids and maximum abundances of A. clausi and O. oculata near the beach. Three upwelling episodes resulted in marked increases in chlorophyll and nutrients, but not in cross-shelf gradients of these properties, as were noted at most other times. Maximum disturbance of cross-shelf zooplankton zonation was observed during a wintertime intrusion of offshore surface water, but the zonation was never obliterated. Nearshore zooplankton patterns appear to be protected from dislocation by the shallow shelf and sustained by phytoplankton distributed in a manner peculiar to the nearshore zone. Typically, shallow nearshore waters were richer in chlorophyll and nutrients than offshore waters of the same depth. The cross-shelf chlorophyll and nutrient profiles, in turn, appear to result from increased eddy diffusion and nutrient recycling in shallow waters, perhaps augmented by longshore transport from quasi-permanent, local upwelling nodes.

Barnett, Arthur M.; Jahn, Andrew E.

1987-01-01

386

Effect of shallow-water hydrothermal venting on the biota of Matupi Harbour (Rabaul Caldera, New Britain Island, Papua New Guinea)  

NASA Astrophysics Data System (ADS)

Coastal hydrothermal vents in the depth range 0-27 m were studied in Matupi Harbour, a marine bight that is partly isolated from the open sea on the north-east coast of New Britain, Papua New Guinea, where volcanoes are active. Planktonic and benthic communities (including bacteria) in the Harbour were compared with adjacent fully marine areas. The env