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Sample records for cyclopoid copepod oithona

  1. Cyclopoid copepods.

    PubMed

    Marten, Gerald G; Reid, Janet W

    2007-01-01

    Cyclopoid copepods have proved more effective for practical mosquito control than any other invertebrate predator of mosquito larvae. Their operational potential is enhanced by the fact that mass production is relatively easy and inexpensive. The exceptional potential of copepods for mosquito control was first realized about 25 years ago. Since then, laboratory experiments with copepods and mosquito larvae around the world have shown: Only the larger copepod species (body length > 1.4 mm) are of practical use for mosquito control. They kill mainly 1st instar mosquitoes. The most effective species have the capacity to kill more than 40 Aedes larvae/copepod/day. They generally kill fewer Anopheles larvae and even fewer Culex larvae. Most field testing of copepods has been in Aedes container-breeding habitats. Field tests have shown that: The most effective copepod species maintain large populations in a container habitat for as long as there is water. They typically reduce Aedes production by 99-100%. They can cause local eradication of container-breeding Aedes mosquitoes if present in a high percentage of breeding sites. Field surveys in Anopheles, floodwater Aedes, and Culex breeding habitats have shown that natural copepod populations can substantially reduce, or even eliminate, mosquito production. Field trials in temporary pools, marshes, and rice fields have demonstrated that introduction of the right copepod species to the right habitat at the right time can eliminate Anopheles or floodwater Aedes larvae. As a rule, copepods cannot eliminate Culex production by themselves, but they can reinforce and augment control by other methods. The only large-scale operational use of copepods to date has been in Vietnam, which has achieved local eradication of Ae. aegypti in hundreds of villages. Conditions in Vietnam are particularly favorable because: Many Ae. aegypti breeding sites are water storage containers that are conspicuous and easily treated. Motivation to maintain copepods in containers for Ae. aegypti control is strong because of the high incidence of dengue hemorrhagic fever. Copepod use is effectively managed by women's associations already experienced with neighborhood health services. Copepods have the potential for local eradication of Ae. aegypti and Ae. albopictus in many other countries besides Vietnam. Professional capacity for copepod management and social institutions for community participation to help with implementation and maintenance are the main factors limiting broader use of copepods for operational mosquito control at the present time. PMID:17853599

  2. Cyclopoid and harpacticoid copepods of the Laurentian Great Lakes

    USGS Publications Warehouse

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

    1998-01-01

    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.

  3. Lagrangian modelling of swimming behaviour and encounter success in co-occurring copepods: Clausocalanus furcatus vs. Oithona plumifera

    NASA Astrophysics Data System (ADS)

    Uttieri, M.; Sabia, L.; Cianelli, D.; Strickler, J. R.; Zambianchi, E.

    2010-04-01

    The calanoid Clausocalanus furcatus and the cyclopoid Oithona plumifera are species dominating the copepod assemblage in oligotrophic environments but displaying contrasting swimming behaviour. C. furcatus moves almost continuously along very convoluted trajectories, while O. plumifera sinks slowly with occasional brief relocating jumps. To evaluate the efficiency of such opposing behaviour in encountering potential prey, the swimming performances of both species are here simulated with a Lagrangian, individual-based approach, implemented to simulate the realistic motion and perceptive fields of the two species. For each modelled swimming trajectory, we calculate the number of realised encounters and the associated search efficiency in uniform and patchy distributions of virtual prey. C. furcatus will perform better than O. plumifera in terms of realised encounters, but its search efficiency will be lower owing to the peculiar motion behaviour and to the shape and extension of the perceptive field. Despite these differences, these two species do co-exist in food diluted areas, thus indicating alternative strategies to successfully thrive in pelagic oligotrophic environments.

  4. [Interannual Variations in Abundance and Biomass of Planktonic Copepods Oithona in the Barents Sea].

    PubMed

    Dvoretsky, V G; Dvoretsky, A G

    2015-01-01

    The distribution patterns of the common arctic zooplankton species Oithona similis and Oithona atlantica were investigated in the Barents Sea during warm and temperate years. The maximum abundance and biomass of Oithona spp. (159 x 10(3) ind./m2 and 38.8 mgC/m2, respectively) were recorded in the waters of Atlantic origin. O. atlantica occurred in Arctic waters only during anomalously warm years. It has been found that the quantitative characteristics of O. similis were negatively correlated with salinity and the winter NAO index, whereas the abundance of O. atlantica in Atlantic waters was positively correlated with the temperature anomaly. It is found that the abundance and biomass of Oithona pp. were comparable with the values recorded in other Arctic regions. PMID:26638241

  5. RNA-seq based whole transcriptome analysis of the cyclopoid copepod Paracyclopina nana focusing on xenobiotics metabolism.

    PubMed

    Lee, Bo-Young; Kim, Hui-Su; Choi, Beom-Soon; Hwang, Dae-Sik; Choi, Ah Young; Han, Jeonghoon; Won, Eun-Ji; Choi, Ik-Young; Lee, Seung-Hwi; Om, Ae-Son; Park, Heum Gi; Lee, Jae-Seong

    2015-09-01

    Copepods are among the most abundant taxa in marine invertebrates, and cyclopoid copepods include more than 1500 species and subspecies. In marine ecosystems, planktonic copepods play a significant role as food resources in the food web and sensitively respond to environmental changes. The copepod Paracylopina nana is one of the planktonic brackish water copepods and considered as a promising model species in ecotoxicology. We sequenced the whole transcriptome of P. nana using RNA-seq technology. De novo sequence assembly by Trinity integrated with TransDecoder produced 67,179 contigs including putative alternative spliced variants. A total of 12,474 genes were identified based on BLAST analysis, and gene sequences were most similar to the sequences of the branchiopod Daphnia. Gene Ontology and KEGG pathway analysis showed that most transcripts annotated were involved in pathways of various metabolisms, immune system, signal transduction, and translation. Considering numbers of sequences and enzymes involved in the pathways, particularly attention was paid to genes potentially involved in xenobiotics biodegradation and metabolism. With regard to xenobiotics metabolism, various xenobiotic metabolizing enzymes such as oxidases, dehydrogenases, and transferases were obtained from the annotated transcripts. The whole transcriptome analysis of P. nana provides valuable resources for future studies of xenobiotics-related metabolism in this marine copepod species. PMID:26001055

  6. Observations on the reproductive biology of two cyclopoid copepods: Oncaea media and O. scottodicarloi

    NASA Astrophysics Data System (ADS)

    Fyttis, Georgios; Demetriou, Monica; Di Capua, Iole; Samuel-Rhoads, Yianna

    2015-04-01

    The small cyclopoid copepods Oncaea media and O. scottodicarloi are important components of the zooplanktonic communities in the Mediterranean Sea due to their numerical abundance and common distribution in coastal and open waters. However, knowledge on their biology is still limited. The present study was aimed to acquire data on their reproductive traits to highlight any difference between these two co-occurring oncaeids that are very similar in size and morphology. Experiments were conducted in the laboratory by monitoring groups of Oncaea ovigerous females (O. media + O. scottodicarloi) sorted from zooplankton samples collected in February and March 2013 from coastal waters in the inner Gulf of Naples (Tyrrhenian Sea, Western Mediterranean). The females were incubated individually at in situ temperature (15 C) in cell culture plates containing oxygenated seawater with food particles that was changed every other day. The plates were inspected daily under an inverted microscope to count the hatched nauplii and measure the interclutch period, until all females were dead and subsequently identified as O. media or O. scottodicarloi. Both species carry the eggs in two dorsal sacs where the eggs are densely packed and cannot be precisely counted. The clutch size was therefore estimated from egg sacs detached from ovigerous females sorted from the same samples and fixed. The average number of eggs per sac was 35.26.6 (range 20-52) for O. media and 24.44.5 (range 14-32) for O. scottodicarloi. Egg production rates (EPR) were estimated to be on average 8.75 eggs female-1 day-1 for O. media and 6.15 eggs female-1 day-1 for O. scottodicarloi. The average egg development time was 8.053.78 days for O. media and 7.90.89 days for O. scottodicarloi. The interclutch period for the females that produced new egg sacs was 2.21.3 days for O. media and 32.7 days for O. scottodicarloi. The average recruitment of O. media was 7.63.7 nauplii f-1 d-1, with the minimum number of hatched nauplii being 4 and the maximum 93. O. scottodicarloi recruited on average 6.54.4 nauplii f-1 d-1, with the minimum number of hatched nauplii from one female being 17 and the maximum 50. O. media and O. scottodicarloi differed significantly (p

  7. Identification and molecular characterization of dorsal and dorsal-like genes in the cyclopoid copepod Paracyclopina nana.

    PubMed

    Jeong, Chang-Bum; Lee, Min Chul; Lee, Kyun-Woo; Seo, Jung Soo; Park, Heum Gi; Rhee, Jae-Sung; Lee, Jae-Seong

    2015-12-01

    To date, knowledge of the immune system in aquatic invertebrates has been reported in only a few model organisms, even though all metazoans have an innate immune system. In particular, information on the copepod's immunity and the potential role of key genes in the innate immune systems is still unclear. In this study, we identified dorsal and dorsal-like genes in the cyclopoid copepod Paracyclopina nana. In silico analyses for identifying conserved domains and phylogenetic relationships supported their gene annotations. The transcriptional levels of both genes were slightly increased from the nauplius to copepodid stages, suggesting that these genes are putatively involved in copepodid development of P. nana. To examine the involvement of both genes in the innate immune response and under stressful conditions, the copepods were exposed to lipopolysaccharide (LPS), different culture densities, salinities, and temperatures. LPS significantly upregulated mRNA expressions of dorsal and dorsal-like genes, suggesting that both genes are transcriptionally sensitive in response to immune modulators. Exposure to unfavorable culture conditions also increased mRNA levels of dorsal and dorsal-like genes. These findings suggest that transcriptional regulation of the dorsal and dorsal-like genes would be associated with environmental changes in P. nana. PMID:26297599

  8. On the uncertainty beneath the name Oithona similis Claus, 1866 (Copepoda, Cyclopoida)

    PubMed Central

    Cepeda, Georgina D.; Sabatini, Marina E.; Scioscia, Cristina L.; Ramírez, Fernando C.; Viñas, María D.

    2016-01-01

    Abstract The marine cyclopoid Oithona similis sensu lato Claus, 1866, is considered to be one of the most abundant and ubiquitous copepods in the world. However, its minimal original diagnosis and the unclear connection with its (subjective) senior synonym Oithona helgolandica Claus, 1863, may have caused frequent misidentification of the species. Consequently, it seems possible that several closely related but distinct forms are being named Oithona similis or Oithona helgolandica without explicit and accurate discrimination. Here the current situation concerning the correct assignment of the two species is revised, the morphological characters commonly used to identify and distinguish each species are summarized, and the nomenclatural implications of indiscriminately using these names in current taxonomic and ecological practice is considered. It is not intended to upset a long-accepted name in its accustomed meaning but certainly the opposite. “In pursuit of the maximum stability compatible with taxonomic freedom” (International Commission of Zoological Nomenclature), we consider that reassessment of the diagnostic characters of Oithona similis sensu stricto cannot be postponed much longer. While a consensus on taxonomy and nomenclatural matters can be attained, we strongly recommend specifically reporting the authority upon which the identification of either Oithona similis s.l. or Oithona helgolandica s.l. has been accomplished. PMID:26865812

  9. On the uncertainty beneath the name Oithona similis Claus, 1866 (Copepoda, Cyclopoida).

    PubMed

    Cepeda, Georgina D; Sabatini, Marina E; Scioscia, Cristina L; Ramrez, Fernando C; Vias, Mara D

    2016-01-01

    The marine cyclopoid Oithona similis sensu lato Claus, 1866, is considered to be one of the most abundant and ubiquitous copepods in the world. However, its minimal original diagnosis and the unclear connection with its (subjective) senior synonym Oithona helgolandica Claus, 1863, may have caused frequent misidentification of the species. Consequently, it seems possible that several closely related but distinct forms are being named Oithona similis or Oithona helgolandica without explicit and accurate discrimination. Here the current situation concerning the correct assignment of the two species is revised, the morphological characters commonly used to identify and distinguish each species are summarized, and the nomenclatural implications of indiscriminately using these names in current taxonomic and ecological practice is considered. It is not intended to upset a long-accepted name in its accustomed meaning but certainly the opposite. "In pursuit of the maximum stability compatible with taxonomic freedom" (International Commission of Zoological Nomenclature), we consider that reassessment of the diagnostic characters of Oithona similis sensu stricto cannot be postponed much longer. While a consensus on taxonomy and nomenclatural matters can be attained, we strongly recommend specifically reporting the authority upon which the identification of either Oithona similis s.l. or Oithona helgolandica s.l. has been accomplished. PMID:26865812

  10. First report of the planktonic copepod Oithona davisae in the northern Wadden Sea (North Sea): Evidence for recent invasion?

    NASA Astrophysics Data System (ADS)

    Cornils, Astrid; Wend-Heckmann, Britta

    2015-06-01

    In October 2010, specimens of Oithona were taken from the List Tidal Basin in the northern Wadden Sea (North Sea) for a biogeographic study on Oithona similis. These specimens could not be assigned to O. similis or any of the other Oithona species known from the North Sea genetically. These specimens were identified as Oithona davisae Ferrari and Orsi 1984, a Northwest Pacific species, known as an invasive species from the Black Sea and the northwestern Mediterranean Sea. Recent sampling provided evidence that O. davisae is still present in the northern Wadden Sea and may thus now be a permanent plankton species.

  11. A new marine cyclopoid copepod of the genus Neocyclops (Cyclopidae, Halicyclopinae) from Korea

    PubMed Central

    Lee, Jimin; Chang, Cheon Young

    2015-01-01

    Abstract A new cyclopoid species of the genus Neocyclops Gurney, 1927 is described. Type specimens were collected from a beach on south-western coast of the Korean Peninsula by rinsing intertidal coarse sandy sediments. Neocyclops hoonsooi sp. n. is most characteristic in showing the conspicuous chitinized transverse ridges originating from the medial margins of the coxae of all swimming legs. The new species is most similar to Neocyclops vicinus, described from the Brazilian coast, and Neocyclops petkovskii, from Australia. All three species share a large body size (more than 750 µm long), the presence of an exopodal seta on the antenna, two setae on the mandibular palp, the same seta/spine armature on the third endopodal segment of leg 3 (3 setae + 3 spines), and the fairly long inner distal spine on the third endopodal segment of the female leg 4. However, Neocyclops hoonsooi sp. n. differs from both species by the much shorter caudal rami (less than 1.7 times as long as wide) and the shorter dorsal caudal seta VII. Furthermore, Neocyclops hoonsooi is clearly distinguished from Neocyclops vicinus by the 10-segmented antennule (vs 12 segments in Neocyclops vicinus), and from Neocyclops petkovskii by the elongate inner distal spine on leg 5 exopod and the 3-segmented leg 5 in male (vs 4-segmented in Neocyclops petkovskii). A tabular comparison of characters separating Neocyclops hoonsooi from its closest allies and a key to Neocyclops species from the Indo-Pacific Ocean are provided. This is the first record of the genus Neocyclops from the northern Pacific. PMID:26448716

  12. Quantitative variability of the copepod assemblages in the northern Adriatic Sea from 1993 to 1997

    NASA Astrophysics Data System (ADS)

    Krini?, Frano; Bojani?, Dubravka; Precali, Robert; Kraus, Romina

    2007-09-01

    Quantitative variability of the copepod assemblages in the northern Adriatic Sea was investigated at two stations, during 43 cruises, from January 1993 to October 1997. Samples were taken at 0.5, 10, and 20 m, as well as near the bottom, using 5-l Niskin bottles. For inter-annual variation in the density of copepod assemblages data were presented as total number of nauplii and copepodites with adult copepods of the following groups: Calanoida, Cyclopoida-oithonids, Cyclopoida-oncaeids and Harpacticoida. Moreover, hydrographic conditions, both fractions of phytoplankton, non-loricate ciliates and tintinnids were taken into consideration. Nauplii are the most numerous fraction at both stations with an average over 74% in the total number of all copepod groups. Their numbers were significantly higher at the western eutrophic station, while at the eastern oligotrophic station, an absolute maximum of 693 ind. l -1 was noted. The maximum values of calanoids and oithonids occur generally during summer and these copepods are always more numerous at the western station: 33-50% and 50-63%, respectively. The most abundant taxa identified were the calanoid Paracalanus parvus and the cyclopoid Oithona nana. Oncaeid species Oncaea waldemari and Monothula subtilis dominated during late autumn and winter. An atypical increase in the abundance of oncaeids during the summer of 1997 could be related to an invasion and mass occurrence of the calycophoran siphonophore Muggiaea atlantica. It can be concluded that these dominant copepods are responsible for the stabilization of very complex processes. Atypical appearances of major copepod groups and disturbances in the copepod population structure itself can significantly influence changes in the ecosystem of this very sensitive region.

  13. Identification of the Full 46 Cytochrome P450 (CYP) Complement and Modulation of CYP Expression in Response to Water-Accommodated Fractions of Crude Oil in the Cyclopoid Copepod Paracyclopina nana.

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Kim, Hui-Su; Nelson, David R; Lee, Su-Jae; Park, Heum Gi; Lee, Jae-Seong

    2015-06-01

    The 46 cytochrome P450 (CYP) gene superfamily was identified in the marine copepod Paracyclopina nana after searching an RNA-seq database and comparing it with other copepod CYP gene families. To annotate the 46 Pn-CYP genes, a phylogenetic analysis of CYP genes was performed using a Bayesian method. Pn-CYP genes were separated into five different clans: CYP2, CYP3, CYP20, CYP26, and mitochondrial. Among these, the principal Pn-CYP genes involved in detoxification were identified by comparing them with those of the copepod Tigriopus japonicus and were examined with respect to their responses to exposure to a water-accommodated fraction (WAF) of crude oil and to the alkylated forms of two polycyclic aromatic hydrocarbons (PAHs; phenanthrene and fluorene). The expression of two Pn-CYP3027 genes (CYP3027F1 and CYP3027F2) was increased in response to WAF exposure and also was upregulated in response to the two alkylated PAHs. In particular, Pn-CYP3027F2 showed the most notable increase in response to 80% WAF exposure. These two responsive CYP genes (Pn-CYP3027F1 and CYP3027F2) were also phylogenetically clustered into the same clade of the WAF- and alkylated PAH-specific CYP genes of the copepod T. japonicus, suggesting that these CYP genes would be those chiefly involved in detoxification in response to WAF exposure in copepods. In this paper, we provide information on the copepod P. nana CYP gene superfamily and also speculate on its potential role in the detoxification of PAHs in marine copepods. Despite the nonlethality of WAF, Pn-CYP3027F2 was rapidly and significantly upregulated in response to WAF that may serve as a useful biomarker of 40% or higher concentration of WAF exposure. This paper will be helpful to better understand the molecular mechanistic events underlying the metabolism of environmental toxicants in copepods. PMID:25942333

  14. 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)

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

    2014-11-01

    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 μm) 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.

  15. Copepod abundance and species composition in the Eastern subtropical/tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Schnack-Schiel, Sigrid B.; Mizdalski, Elke; Cornils, Astrid

    2010-12-01

    Abundance and species composition of copepods were studied during the expedition ANT XXI/1 on a latitudinal transect in the eastern Atlantic from 3449.5'N to 2728.1'S between 2-20 November 2002. Stratified zooplankton tows were carried out at 19 stations with a multiple opening-closing net between 300 m water depth and the surface. Cyclopoid and calanoid copepods showed similar patterns of distribution and abundance. Oithona was the most abundant cyclopoid genus, followed by Oncaea. A total of 149 calanoid copepod species were identified. Clausocalanus was by far the most abundant genus, comprising on average about 45% of all calanoids, followed by Calocalanus (13%), Delibus (9%), Paracalanus (6%), and Pleuromamma (5%). All other genera comprised on average less than 5% each, with 40 genera less than 1%. The calanoid copepod communities were distinguished broadly in accordance with sea surface temperature, separating the subtropical from the tropical stations, and were largely determined by variation in species composition and species abundance. Nine Clausocalanus species were identified. The most numerous Clausocalanus species was C. furcatus, which on average comprised half of all adult of this genus. C. pergens, C. paululus, and C. jobei, contributed an average of 19%, 9%, and 9%, respectively. The Clausocalanus species differed markedly in their horizontal and vertical distributions: C. furcatus, C. jobei, and C. mastigophorus had widespread distributions and inhabited the upper water layers. Major differences between the species were found in abundance. C. paululus and C. arcuicornis were biantitropical and were absent or occurred in very low numbers in the equatorial zone. C. parapergens was found at all stations and showed a bimodal distribution pattern with maxima in the subtropics. C. pergens occurred in higher numbers only at the southern stations, where it replaced C. furcatus in dominance. In contrast to the widespread species, the bulk of the C. paululus, C. arcuicornis, C. parapergens, and C. pergens populations was concentrated in the colder, deeper water layers below the thermocline, thereby avoiding the warm surface waters. C. lividus was found only at the most northern and C. ingens only at the most southern stations. Both species were found almost exclusively in the upper 50 m. The distinct differences in abundance and horizontal and vertical distribution suggest a strong ecological differentiation among the Clausocalanus species.

  16. A numerical investigation of the impact of turbulence on the feeding rates of Oithona davisae

    NASA Astrophysics Data System (ADS)

    Mariani, Patrizio; Botte, Vincenzo; Ribera d'Alcal, Maurizio

    Individual based numerical simulations of the copepod, Oithona davisae, feeding on motile prey, Oxyrrhis marina, under variable turbulent conditions are performed. These simulations correspond to laboratory observations conducted by Saiz et al. [Saiz, E., Calbet, A., and Broglio, E., 2003. Effects of small-scale turbulence on copepods: the case of Oithona Davisae. Limnol. Oceanogr., 48:1304-1311.]. The flow field in the simulation is reconstructed by a kinematic simulation whose characteristic scales are derived from the grid mesh and the dissipation rates of the laboratory experiments. The kinematic simulation provides a simplified model, which while not fully realistic, captures the basic relevant feature of turbulence. A hop and sink swimming behaviour is prescribed for O. davisae, while O. marina moves along helical paths with random changes of directions. Three possible effects are tested: the existence of a time threshold in the duration of the contacts between predator and prey, a progressive reduction of the perceptive distance with increasing turbulence level and an abrupt reduction in feeding of O. davisae when the flow speed, in relation to the copepod position, is higher than a prescribed threshold. This last approach introduces an intermittency in the feeding which depends on the variations of velocity both in space and time within the numerical box. The introduction of the time threshold causes a dome-shaped relationship between the simulated enhancement factor and the dissipation rate, while with the other two effects, a monotonic decrease in the enhancement factor is observed, with values reasonably close to the ones observed in the laboratory experiment. In all the cases, the use of realistic values of biological parameters (e.g. swimming behaviour) reproduces response curves in the range of the observations.

  17. Species composition of Black Sea marine planktonic copepods

    NASA Astrophysics Data System (ADS)

    Gubanova, A.; Altukhov, D.; Stefanova, K.; Arashkevich, E.; Kamburska, L.; Prusova, I.; Svetlichny, L.; Timofte, F.; Uysal, Z.

    2014-07-01

    This paper reviews the changes in the marine planktonic copepods of the Black Sea species' list from the beginning of taxonomic research to the present day. The study was based on the SESAME biological database, unpublished data, literature and data obtained during the course of the SESAME project. Comparisons were made with the Guidebook for Marine Fauna of the Black Sea and the Sea of Azov, which revealed changes both in the taxonomic status of some species and in the structure of the copepod community. The taxonomic status of two species (Acartia clausi small form and Centropages kroyeri pontica) and the nomenclature of two species (Oihona minuta and Calanus helgolandicus) have been changed. Three native species (Acartia margalefi, Oithona nana, and Paracartia latisetosa) have disappeared. Two non-indigenous copepods (Acartia tonsa and Oithona davisae) became established in the Black Sea ecosystem in the 1970s and 2000s, respectively. The success of their establishment was determined by biological features of the species and vulnerability of the native copepod community to invasions. It is highly probable that both species were introduced to the Black Sea by vessel ballast water. The hypothesis of "mediterranization" of the Black Sea fauna does not appear to hold true for zooplankton. Numerous claims of alien copepod species in the Black Sea remain largely unverified due to insufficient information. Data on newly discovered species of the Acartia genus are not authenticated. An updated list of marine planktonic copepods of the Black Sea is hereby presented.

  18. Automated identification of copepods using digital image processing and artificial neural network

    PubMed Central

    2015-01-01

    Background Copepods are planktonic organisms that play a major role in the marine food chain. Studying the community structure and abundance of copepods in relation to the environment is essential to evaluate their contribution to mangrove trophodynamics and coastal fisheries. The routine identification of copepods can be very technical, requiring taxonomic expertise, experience and much effort which can be very time-consuming. Hence, there is an urgent need to introduce novel methods and approaches to automate identification and classification of copepod specimens. This study aims to apply digital image processing and machine learning methods to build an automated identification and classification technique. Results We developed an automated technique to extract morphological features of copepods' specimen from captured images using digital image processing techniques. An Artificial Neural Network (ANN) was used to classify the copepod specimens from species Acartia spinicauda, Bestiolina similis, Oithona aruensis, Oithona dissimilis, Oithona simplex, Parvocalanus crassirostris, Tortanus barbatus and Tortanus forcipatus based on the extracted features. 60% of the dataset was used for a two-layer feed-forward network training and the remaining 40% was used as testing dataset for system evaluation. Our approach demonstrated an overall classification accuracy of 93.13% (100% for A. spinicauda, B. similis and O. aruensis, 95% for T. barbatus, 90% for O. dissimilis and P. crassirostris, 85% for O. similis and T. forcipatus). Conclusions The methods presented in this study enable fast classification of copepods to the species level. Future studies should include more classes in the model, improving the selection of features, and reducing the time to capture the copepod images. PMID:26678287

  19. The fluid dynamics of swimming by jumping in copepods

    PubMed Central

    Jiang, Houshuo; Kirboe, Thomas

    2011-01-01

    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

  20. A new genus and species of cyclopoid (Crustacea, Copepoda, Cyclopinidae) from a coastal system in the Gulf of Mexico

    PubMed Central

    Suárez-Morales, Eduardo; Almeyda-Artigas, Roberto Javier

    2015-01-01

    Abstract A new, monotypic genus of the interstitial marine cyclopoid copepod family Cyclopinidae G.O. Sars, 1913 is described from male and female specimens collected at Laguna de Términos, a large coastal lagoon system in the southern Gulf of Mexico. Mexiclopina campechana gen. et sp. n. cannot be adequately placed in any extant genus within the family. It differs from other cyclopinid genera in having a unique combination of characters including: 1) absence of modified brush-like seta on the mandibular exopod; 2) maxillule exopod with stout setal elements and brush-like setae absent; 3) basis of mandible with one seta; 4) presence of a modified seta on endopod of fourth leg; 5) fifth leg exopod unsegmented, armed with three elements in the female and five in the male; 6) intercoxal sclerite of first swimming leg with two medial spiniform processes on distal margin. The new genus is monotypic and appears to be most closely related to Cyclopina Claus, 1863 and Heptnerina Ivanenko & Defaye, 2004; the new species was compared with species of Cyclopina and it resembles Cyclopina americana Herbst, 1982 and Cyclopina caissara Lotufo, 1994. This is the second record of a species of Cyclopinidae in Mexico and the first in the Gulf of Mexico; the number of cyclopinid species recorded from the Americas is now 13. PMID:26668545

  1. Spatial and temporal variations of pelagic copepods in the North Yellow Sea

    NASA Astrophysics Data System (ADS)

    Chen, Hongju; Liu, Guangxing; Zhu, Yanzhong; Jiang, Qiang

    2015-12-01

    This study aims to analyze the spatial and temporal variations of the abundance and biodiversity of pelagic copepods and their relationships with the environmental factors in the North Yellow Sea (NYS). These variations were analyzed on the basis of the survey data of the NYS in four seasons from 2006 to 2007. A total of 31 copepod species that belong to 17 genera, 13 families and 4 orders were identified in the four seasons. Of these copepods, the species belonging to Calanoida is the most abundant component. The dominant species include Calanus sinicus, Centropages abdominalis, Paracalanus parvus, Acartia bifilosa, Oithona plumifera, and Corycaeus affinis. C. sinicus is the most important and widely distributed dominant species in all of the seasons. The dominant species have not shown any significant variation for the past 50 years. However, the richness of warm-water species increased. The abundance of copepods significantly varied among different seasons: the average abundance was higher in spring (608.2 ind m-3) and summer (385.1 ind m-3) than in winter (186.5 ind m-3) and autumn (128.0 ind m-3). Factor analyses showed a high correlation between the spatial distributions of dominant copepods and environmental parameters, and Chl-a was the most important factor that influenced the distribution of copepods. This research can provide the fundamental information related to zooplankton, especially pelagic copepods. This research is also beneficial for the long-term monitoring of zooplankton ecology in the NYS.

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

    PubMed Central

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

    2015-01-01

    Invasive planktonic crustaceans have become a prominent feature of aquatic communities worldwide, yet their effects on food webs are not well known. The Asian calanoid copepod, Pseudodiaptomus forbesi, introduced to the Columbia River Estuary approximately 15 years ago, now dominates the late-summer zooplankton community, but its use by native aquatic predators is unknown. We investigated whether three species of planktivorous fishes (chinook salmon, three-spined stickleback, and northern pikeminnow) and one species of mysid exhibited higher feeding rates on native copepods and cladocerans relative to P. forbesi by conducting `single-prey’ feeding experiments and, additionally, examined selectivity for prey types with `two-prey’ feeding experiments. In single-prey experiments individual predator species showed no difference in feeding rates on native cyclopoid copepods (Cyclopidae spp.) relative to invasive P. forbesi, though wild-collected predators exhibited higher feeding rates on cyclopoids when considered in aggregate. In two-prey experiments, chinook salmon and northern pikeminnow both strongly selected native cladocerans (Daphnia retrocurva) over P. forbesi, and moreover, northern pikeminnow selected native Cyclopidae spp. over P. forbesi. On the other hand, in two-prey experiments, chinook salmon, three-spined stickleback and mysids were non- selective with respect to feeding on native cyclopoid copepods versus P. forbesi. Our results indicate that all four native predators in the Columbia River Estuary can consume the invasive copepod, P. forbesi, but that some predators select for native zooplankton over P. forbesi, most likely due to one (or both) of two possible underlying casual mechanisms: 1) differential taxon-specific prey motility and escape responses (calanoids > cyclopoids > daphnids) or 2) the invasive status of the zooplankton prey resulting in naivety, and thus lower feeding rates, of native predators feeding on invasive prey. PMID:26618851

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

    PubMed

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

    2013-12-17

    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

  4. Copepod (Crustacea) emergence from soils from everglades marshes with different hydroperiods

    USGS Publications Warehouse

    Loftus, W.F.; Reid, J.W.

    2000-01-01

    During a severe drought period in the winter and spring of 1989, we made three collections of dried marsh soils from freshwater sloughs in Everglades National Park, Florida, at sites characterized by either long or intermediate annual periods of flooding (hydroperiod). After rehydrating the soils in aquaria, we documented the temporal patterns of copepod emergence over two-week periods. The species richness of copepods in the rehydrated soils was lower than in pre-drought samples from the same slough sites. Only six of the 16 species recorded from the Everglades emerged in the aquarium tests. The long hydroperiod site had a slightly different assemblage and higher numbers of most species than the intermediate-hydroperiod sites. More individuals and species emerged from the early dry-season samples compared with samples taken later in the dry season. The harpacticoid, Cletocamptus deitersi, and the cyclopoid, Microcyclops rubellus, were abundant at most sites. The cyclopoids - Ectocyclops phaleratus, Homocyclops ater, and Paracyclops chiltoni - are new records for the Everglades. We infer that 1) only a subset of Everglades copepod species can survive drought by resting in soils; and that 2) survival ability over time differs by species.

  5. Ecology and role of benthic copepods in northern lakes

    NASA Astrophysics Data System (ADS)

    Sarvala, J.

    1998-06-01

    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.

  6. Toxicity of seaweed-synthesized silver nanoparticles against the filariasis vector Culex quinquefasciatus and its impact on predation efficiency of the cyclopoid crustacean Mesocyclops longisetus.

    PubMed

    Murugan, Kadarkarai; Benelli, Giovanni; Ayyappan, Suganya; Dinesh, Devakumar; Panneerselvam, Chellasamy; Nicoletti, Marcello; Hwang, Jiang-Shiou; Kumar, Palanisamy Mahesh; Subramaniam, Jayapal; Suresh, Udaiyan

    2015-06-01

    Nearly 1.4 billion people in 73 countries worldwide are threatened by lymphatic filariasis, a parasitic infection that leads to a disease commonly known as elephantiasis. Filariasis is vectored by mosquitoes, with special reference to the genus Culex. The main control tool against mosquito larvae is represented by treatments with organophosphates and insect growth regulators, with negative effects on human health and the environment. Recently, green-synthesized nanoparticles have been proposed as highly effective larvicidals against mosquito vectors. In this research, we attempted a reply to the following question: do green-synthesized nanoparticles affect predation rates of copepods against mosquito larvae? We proposed a novel method of seaweed-mediated synthesis of silver nanoparticles using the frond extract of Caulerpa scalpelliformis. The toxicity of the seaweed extract and silver nanoparticles was assessed against the filarial vector Culex quinquefasciatus. Then, we evaluated the predatory efficiency of the cyclopoid crustacean Mesocyclops longisetus against larval instars of C. quinquefasciatus in a nanoparticle-contaminated water environment. Green-synthesized silver nanoparticles were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In mosquitocidal assays, the LC?? values of the C. scalpelliformis extract against C. quinquefasciatus were 31.38 ppm (I), 46.49 ppm (II), 75.79 ppm (III), 102.26 ppm (IV), and 138.89 ppm (pupa), while LC?? of silver nanoparticles were 3.08 ppm, (I), 3.49 ppm (II), 4.64 ppm (III), 5.86 ppm (IV), and 7.33 ppm (pupa). The predatory efficiency of the copepod M. longisetus in the control treatment was 78 and 59% against I and II instar larvae of C. quinquefasciatus. In a nanoparticle-contaminated environment, predation efficiency was 84 and 63%, respectively. Predation was higher against first instar larvae over other instars. Overall, our study showed that seaweed-synthesized silver nanoparticles can be proposed in synergy with biological control agents against Culex larvae, since their use leads to little detrimental effects against aquatic predators, such as copepods. PMID:25782680

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

    PubMed Central

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

    2013-01-01

    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 μatm 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 μatm, 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

  8. Copepod Response Behavior in Turbulence

    NASA Astrophysics Data System (ADS)

    Krizan, Daniel

    The objective of this thesis is to determine copepod response to turbulence generated by obstacles in cross flow. Mainly, flow and copepod response downstream a square fractal grid is examined but experiments downstream a cylinder provides comparison. This is done by simultaneously measuring the copepods position and velocity using 3D-PTV in a measurement volume and measuring the two dimensional three component velocity vectors of the flow using stereo PIV. These measurements are done in a way that does not elicit copepod response. Tomographic PIV is done downstream the square fractal grid without copepods to gain volumetric velocity knowledge of the flow in the measurement volume. Copepods are known to execute sudden high speed jumps (or escapes) in response to sensed hydrodynamic signals. The fractal grid was shown to elicit copepod escape, specifically directly downstream with escape frequency decreasing further downstream where turbulence levels were much lower. It was found that at a slower freestream speed copepods exhibited jumps not in reaction to flow disturbances but to reorient themselves (cruise swimming). There was almost no copepod response in the wake of a cylinder, but copepods again exhibited cruise swimming behavior at a slower freestream speed. In regions with high maximum principal strain rate (MPSR) downstream of the fractal grid, copepods were observed to exhibit multiple escapes. Moreover, copepods were observed to jump towards regions of lower turbulence and against the freestream direction. From stereo PIV, instantaneous 2D MPSR values of less than 3s -1 were shown to create escape in 60% of copepod escapes analyzed. Finally, it was found that on average larger MPSR resulted in larger jumps from copepods.

  9. The Kinematics of Swimming and Relocation Jumps in Copepod Nauplii

    PubMed Central

    Andersen Borg, Christian Marc; Bruno, Eleonora; Kirboe, Thomas

    2012-01-01

    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

  10. Lethal and Sublethal Toxicity Comparison of BFRs to Three Marine Planktonic Copepods: Effects on Survival, Metabolism and Ingestion.

    PubMed

    Gong, Wenjing; Zhu, Liyan; Hao, Ya

    2016-01-01

    The estuarine planktonic copepods have a wide geographical distribution and commendable tolerance to various kinds of contaminants. The primary aim of the present study was to contrast the impacts of model POPs (TBBPA and HBCD) on three common estuarine planktonic copepods (Oithona similis, Acartia pacifica and Pseudodiaptomus inopinus) and establish a protocol for the assessment of acute toxicity of marine organic pollutants. We first quantified the 96h-LC50 (0.566, 0.04 and 0.257 mg/L of TBBPA to the three subjects above respectively and 0.314 mg/L of HBCD to P. inopinus; all reported concentrations are nominal values). In the sub-lethal toxicity tests, it was turned out that the effects of copepods exposed to TBBPA could product different influences on the energy ingestion and metabolism. Different type of pollutions, meanwhile, could also bring varying degree effect on the target copepods. In general, the indicators (the rate of oxygen consumption, ammonia excretion, food ingestion and filtration) in higher concentration groups showed marked significant difference compared with controls as well a dose-effect relationship. The study also extended the research on the joint toxicity of TBBPA and HBCD based on the survival rate of P.inopinus. Whether 1:1 concentration or 1:1 toxic level, the research showed synergy effect relative to single exposure conditions. The result indicated that current single ecological testing used for environmental protection activities may underestimate the risk for copepods. It was also demonstrated that short-term sub-lethal experiment could be a standard to evaluate the sensitivity of copepods to POPs. PMID:26824601

  11. Lethal and Sublethal Toxicity Comparison of BFRs to Three Marine Planktonic Copepods: Effects on Survival, Metabolism and Ingestion

    PubMed Central

    Gong, Wenjing; Zhu, Liyan; Hao, Ya

    2016-01-01

    The estuarine planktonic copepods have a wide geographical distribution and commendable tolerance to various kinds of contaminants. The primary aim of the present study was to contrast the impacts of model POPs (TBBPA and HBCD) on three common estuarine planktonic copepods (Oithona similis, Acartia pacifica and Pseudodiaptomus inopinus) and establish a protocol for the assessment of acute toxicity of marine organic pollutants. We first quantified the 96h-LC50 (0.566, 0.04 and 0.257 mg/L of TBBPA to the three subjects above respectively and 0.314 mg/L of HBCD to P. inopinus; all reported concentrations are nominal values). In the sub-lethal toxicity tests, it was turned out that the effects of copepods exposed to TBBPA could product different influences on the energy ingestion and metabolism. Different type of pollutions, meanwhile, could also bring varying degree effect on the target copepods. In general, the indicators (the rate of oxygen consumption, ammonia excretion, food ingestion and filtration) in higher concentration groups showed marked significant difference compared with controls as well a dose-effect relationship. The study also extended the research on the joint toxicity of TBBPA and HBCD based on the survival rate of P.inopinus. Whether 1:1 concentration or 1:1 toxic level, the research showed synergy effect relative to single exposure conditions. The result indicated that current single ecological testing used for environmental protection activities may underestimate the risk for copepods. It was also demonstrated that short-term sub-lethal experiment could be a standard to evaluate the sensitivity of copepods to POPs. PMID:26824601

  12. A new species of philichthyid copepod (Crustacea: Cyclopoida) parasitic on
    Stellifer spp. (Perciformes: Sciaenidae) from southeastern Brazil.

    PubMed

    Pombo, Mara; Turra, Alexander; Paschoal, Fabiano; Luque, Jos Luis

    2015-01-01

    A new species of copepod, Colobomatus stelliferi n. sp., belonging to the cyclopoid family Philichthyidae Vogt, 1877 is proposed based on female specimens collected from the mandibular canals of three species of sciaenid teleosts: Stellifer brasiliensis (Schultz) (type-host), S. rastrifer (Jordan) and S. stellifer (Bloch), collected in Caraguatatuba Bay, State of So Paulo, Brazil. The new species can be distinguished from its closest congeners by the absence of lateral processes in the genital somite, the presence of one cephalic process in the cephalosome and one pair of dorso-lateral processes on the fused pedigerous somites. This is the first species of Colobomatus Hesse, 1873 described as parasites of species of the teleost genus Stellifer. PMID:25781754

  13. Senescence and sexual selection in a pelagic copepod.

    PubMed

    Ceballos, Sara; Kiørboe, Thomas

    2011-01-01

    The ecology of senescence in marine zooplankton is not well known. Here we demonstrate senescence effects in the marine copepod Oithona davisae and show how sex and sexual selection accelerate the rate of ageing in the males. We show that adult mortality increases and male mating capacity and female fertility decrease with age and that the deterioration in reproductive performance is faster for males. Males have a limited mating capacity because they can fertilize < 2 females day(-1) and their reproductive life span is 10 days on average. High female encounter rates in nature (>10 day(-1)), a rapid age-dependent decline in female fertility, and a high mortality cost of mating in males are conducive to the development of male choosiness. In our experiments males in fact show a preference for mating with young females that are 3 times more fertile than 30-day old females. We argue that this may lead to severe male-male competition for young virgin females and a trade-off that favours investment in mate finding over maintenance. In nature, mate finding leads to a further elevated mortality of males, because these swim rapidly in their search for attractive partners, further relaxing fitness benefits of maintenance investments. We show that females have a short reproductive period compared to their average longevity but virgin females stay fertile for most of their life. We interpret this as an adaptation to a shortage of males, because a long life increases the chance of fertilization and/or of finding a high quality partner. The very long post reproductive life that many females experience is thus a secondary effect of such an adaptation. PMID:21533149

  14. Senescence and Sexual Selection in a Pelagic Copepod

    PubMed Central

    Ceballos, Sara; Kirboe, Thomas

    2011-01-01

    The ecology of senescence in marine zooplankton is not well known. Here we demonstrate senescence effects in the marine copepod Oithona davisae and show how sex and sexual selection accelerate the rate of ageing in the males. We show that adult mortality increases and male mating capacity and female fertility decrease with age and that the deterioration in reproductive performance is faster for males. Males have a limited mating capacity because they can fertilize < 2 females day?1 and their reproductive life span is 10 days on average. High female encounter rates in nature (>10 day?1), a rapid age-dependent decline in female fertility, and a high mortality cost of mating in males are conducive to the development of male choosiness. In our experiments males in fact show a preference for mating with young females that are 3 times more fertile than 30-day old females. We argue that this may lead to severe male-male competition for young virgin females and a trade-off that favours investment in mate finding over maintenance. In nature, mate finding leads to a further elevated mortality of males, because these swim rapidly in their search for attractive partners, further relaxing fitness benefits of maintenance investments. We show that females have a short reproductive period compared to their average longevity but virgin females stay fertile for most of their life. We interpret this as an adaptation to a shortage of males, because a long life increases the chance of fertilization and/or of finding a high quality partner. The very long post reproductive life that many females experience is thus a secondary effect of such an adaptation. PMID:21533149

  15. The fate of biogenic iron during a phytoplankton bloom induced by natural fertilisation: Impact of copepod grazing

    NASA Astrophysics Data System (ADS)

    Sarthou, Graldine; Vincent, Dorothe; Christaki, Urania; Obernosterer, Ingrid; Timmermans, Klaas R.; Brussaard, Corina P. D.

    2008-03-01

    The impact of copepod grazing on Fe regeneration was investigated in a naturally iron-fertilised area during Kerguelen Ocean and Plateau compared Study (KEOPS, Jan.-Feb. 2005). 55Fe-labelled natural plankton assemblages (<200 ?m) were offered as food to copepod predators sampled in the field ( Calanus propinquus, Rhincalanus gigas, Metridia lucens and Oithona frigida). Diatoms ( Eucampia antarctica, Corethron inerme and Navicula spp.) constituted the bulk of the protists whereas microzooplankton (i.e. ciliates and dinoflagellates) were in very low abundance. Copepod grazing on phytoplankton ranged from 0.3 to 2.6 ?gC ind -1 d -1 and reflected low utilisation of the food stocks (1-10% of total Chlorophyll a d -1) and low daily rations (0.2-3.3% body C d -1). Copepod grazing resulted in a 1.7-2.3-fold increase in Fe regeneration. Less than 1% of the regenerated Fe was complexed with hydrophobic organic ligands, as determined by extraction onto hydrophobic C18 columns. This suggests that Fe was regenerated as inorganic species and/or bound to freely soluble organic ligands. The biogenic Fe budget established from our study and literature based data indicates that most of the primary production is recycled through the detrital pool, which represents the largest Fe pool (49% of total Fe). Our iron budget further indicates that mesozooplankton and diatoms represent the dominant Fe biomasses above the Kerguelen plateau. The rate of Fe regeneration accounts for half of the Fe demand, strengthening the need for new Fe sources to sustain the massive phytoplankton bloom above the Kerguelen plateau.

  16. Changes in lipid composition of copepods and Euphausia superba associated with diet and environmental conditions in the marginal ice zone, Bellingshausen Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Cripps, G. C.; Hill, H. J.

    1998-08-01

    The effect of varying diet and environmental conditions at the Marginal Ice Zone (MIZ) on the fatty acid and hydrocarbon compositions of five species of copepod and krill, Euphausia superba, was investigated. Zooplankton at the MIZ experienced a range of conditions, from a low algal biomass (mainly flagellates) under pack-ice to a spring bloom dominated by diatoms in the open ocean. Principal Component Analysis classified the copepods into three dietary regimes: (i) omnivores or general algal feeders under the pack ice, (ii) dinoflagellate feeders, and (iii) diatom feeders in the open ocean. This classification was supported by the distribution of the diatom marker n-heneicosahexaene ( n-C 21:6) and a general indicator of herbivory, the isoprenoid pristane. The fatty acid and hydrocarbon composition reflected dietary preferences and availability as the season progressed. Of the copepods under the pack-ice, Oithona spp. was omnivorous whereas Calanus propinquus was feeding preferentially on flagellates. Metridia gerlachei fed on flagellates in all conditions, but also included diatoms in its diet during the bloom. Calanoides acutus and Rhincalanus gigas, which passed the winter in diapause, were feeding almost exclusively on diatoms in the open ocean. Euphausia superba, which were also mainly diatom feeders in the open ocean, were feeding on the sea-ice algae (diatoms) and suspended material from the water column (dinoflagellates) under the pack-ice.

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

    USGS Publications Warehouse

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

    2001-01-01

    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.

  18. Evolution of bioluminescence in marine planktonic copepods.

    PubMed

    Takenaka, Yasuhiro; Yamaguchi, Atsushi; Tsuruoka, Naoki; Torimura, Masaki; Gojobori, Takashi; Shigeri, Yasushi

    2012-06-01

    Copepods are the dominant taxa in zooplankton communities of the ocean worldwide. Although bioluminescence of certain copepods has been known for more than a 100 years, there is very limited information about the structure and evolutionary history of copepod luciferase genes. Here, we report the cDNA sequences of 11 copepod luciferases isolated from the superfamily Augaptiloidea in the order Calanoida. Highly conserved amino acid residues in two similar repeat sequences were confirmed by the multiple alignment of all known copepod luciferases. Copepod luciferases were classified into two groups of Metridinidae and Heterorhabdidae/Lucicutiidae families based on phylogenetic analyses, with confirmation of the interrelationships within the Calanoida using 18S ribosomal DNA sequences. The large diversity in the specific activity of planktonic homogenates and copepod luciferases that we were able to express in mammalian cultured cells illustrates the importance of bioluminescence as a protective function against predators. We also discuss the relationship between the evolution of copepod bioluminescence and the aspects of their ecological characteristics, such as swimming activity and vertical habitat. PMID:22319154

  19. Optimal mate choice patterns in pelagic copepods.

    PubMed

    Heuschele, Jan; Eliassen, Sigrunn; Kiørboe, Thomas

    2013-06-01

    The importance of sexual selection for the evolution, dynamics and adaptation of organisms is well known for many species. However, the topic is rarely studied in marine plankton, the basis of the marine food web. Copepods show behaviors that suggest the existence of sexually selected traits, and recent laboratory experiments identified some selected morphological traits. Here, we use a 'life history-based' model of sex roles to determine the optimal choosiness behavior of male and female copepods for important copepod traits. Copepod females are predicted to be choosy at population densities typically occurring during the main breeding season, whereas males are not. The main drivers of this pattern are population density and the difference in non-receptive periods between males and females. This suggests that male reproductive traits have evolved mainly due to mate competition. The model can easily be parameterized for other planktonic organisms, and be used to plan experiments about sexual selection. PMID:23180421

  20. 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.

  1. Spliced leader RNA trans-splicing discovered in copepods.

    PubMed

    Yang, Feifei; Xu, Donghui; Zhuang, Yunyun; Yi, Xiaoyan; Huang, Yousong; Chen, Hongju; Lin, Senjie; Campbell, David A; Sturm, Nancy R; Liu, Guangxing; Zhang, Huan

    2015-01-01

    Copepods are one of the most abundant metazoans in the marine ecosystem, constituting a critical link in aquatic food webs and contributing significantly to the global carbon budget, yet molecular mechanisms of their gene expression are not well understood. Here we report the detection of spliced leader (SL) trans-splicing in calanoid copepods. We have examined nine species of wild-caught copepods from Jiaozhou Bay, China that represent the major families of the calanoids. All these species contained a common 46-nt SL (CopepodSL). We further determined the size of CopepodSL precursor RNA (slRNA; 108-158 nt) through genomic analysis and 3'-RACE technique, which was confirmed by RNA blot analysis. Structure modeling showed that the copepod slRNA folded into typical slRNA secondary structures. Using a CopepodSL-based primer set, we selectively enriched and sequenced copepod full-length cDNAs, which led to the characterization of copepod transcripts and the cataloging of the complete set of 79 eukaryotic cytoplasmic ribosomal proteins (cRPs) for a single copepod species. We uncovered the SL trans-splicing in copepod natural populations, and demonstrated that CopepodSL was a sensitive and specific tool for copepod transcriptomic studies at both the individual and population levels and that it would be useful for metatranscriptomic analysis of copepods. PMID:26621068

  2. Spliced leader RNA trans-splicing discovered in copepods

    PubMed Central

    Yang, Feifei; Xu, Donghui; Zhuang, Yunyun; Yi, Xiaoyan; Huang, Yousong; Chen, Hongju; Lin, Senjie; Campbell, David A.; Sturm, Nancy R.; Liu, Guangxing; Zhang, Huan

    2015-01-01

    Copepods are one of the most abundant metazoans in the marine ecosystem, constituting a critical link in aquatic food webs and contributing significantly to the global carbon budget, yet molecular mechanisms of their gene expression are not well understood. Here we report the detection of spliced leader (SL) trans-splicing in calanoid copepods. We have examined nine species of wild-caught copepods from Jiaozhou Bay, China that represent the major families of the calanoids. All these species contained a common 46-nt SL (CopepodSL). We further determined the size of CopepodSL precursor RNA (slRNA; 108-158 nt) through genomic analysis and 3′-RACE technique, which was confirmed by RNA blot analysis. Structure modeling showed that the copepod slRNA folded into typical slRNA secondary structures. Using a CopepodSL-based primer set, we selectively enriched and sequenced copepod full-length cDNAs, which led to the characterization of copepod transcripts and the cataloging of the complete set of 79 eukaryotic cytoplasmic ribosomal proteins (cRPs) for a single copepod species. We uncovered the SL trans-splicing in copepod natural populations, and demonstrated that CopepodSL was a sensitive and specific tool for copepod transcriptomic studies at both the individual and population levels and that it would be useful for metatranscriptomic analysis of copepods. PMID:26621068

  3. Spliced leader RNA trans-splicing discovered in copepods

    NASA Astrophysics Data System (ADS)

    Yang, Feifei; Xu, Donghui; Zhuang, Yunyun; Yi, Xiaoyan; Huang, Yousong; Chen, Hongju; Lin, Senjie; Campbell, David A.; Sturm, Nancy R.; Liu, Guangxing; Zhang, Huan

    2015-12-01

    Copepods are one of the most abundant metazoans in the marine ecosystem, constituting a critical link in aquatic food webs and contributing significantly to the global carbon budget, yet molecular mechanisms of their gene expression are not well understood. Here we report the detection of spliced leader (SL) trans-splicing in calanoid copepods. We have examined nine species of wild-caught copepods from Jiaozhou Bay, China that represent the major families of the calanoids. All these species contained a common 46-nt SL (CopepodSL). We further determined the size of CopepodSL precursor RNA (slRNA; 108-158 nt) through genomic analysis and 3‧-RACE technique, which was confirmed by RNA blot analysis. Structure modeling showed that the copepod slRNA folded into typical slRNA secondary structures. Using a CopepodSL-based primer set, we selectively enriched and sequenced copepod full-length cDNAs, which led to the characterization of copepod transcripts and the cataloging of the complete set of 79 eukaryotic cytoplasmic ribosomal proteins (cRPs) for a single copepod species. We uncovered the SL trans-splicing in copepod natural populations, and demonstrated that CopepodSL was a sensitive and specific tool for copepod transcriptomic studies at both the individual and population levels and that it would be useful for metatranscriptomic analysis of copepods.

  4. Algal Toxins Alter Copepod Feeding Behavior

    PubMed Central

    Hong, Jiarong; Talapatra, Siddharth; Katz, Joseph; Tester, Patricia A.; Waggett, Rebecca J.; Place, Allen R.

    2012-01-01

    Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepods feeding appendagesa sampling beating that has short durations (<100 ms) and involves little fluid entrainment and a longer duration grazing beating that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepods grazing behavior. These findings add critical insight into how these algal toxins may influence the copepods feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods. PMID:22629336

  5. Observing copepods through a genomic lens

    PubMed Central

    2011-01-01

    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

  6. Seasonal dynamics of zooplankton in Columbia–Snake River reservoirs,with special emphasis on the invasive copepod Pseudodiaptomus forbesi

    USGS Publications Warehouse

    Emerson, Joshua E; Bollens, Stephen M; Counihan, Timothy D.

    2014-01-01

    The Asian copepod Pseudodiaptomus forbesi has recently become established in the Columbia River. However, little is known about its ecology and effects on invaded ecosystems. We undertook a 2-year (July 2009 to June 2011) field study of the mesozooplankton in four reservoirs in the Columbia and Snake Rivers, with emphasis on the relation of the seasonal variation in distribution and abundance of P. forbesi to environmental variables. Pseudodiaptomus forbesi was abundant in three reservoirs; the zooplankton community of the fourth reservoir contained no known non-indigenous taxa. The composition and seasonal succession of zooplankton were similar in the three invaded reservoirs: a bloom of rotifers occurred in spring, native cyclopoid and cladoceran species peaked in abundance in summer, and P. forbesi was most abundant in late summer and autumn. In the uninvaded reservoir, total zooplankton abundance was very low year-round. Multivariate ordination indicated that temperature and dissolved oxygen were strongly associated with zooplankton community structure, with P. forbesi appearing to exhibit a single generation per year . The broad distribution and high abundance of P. forbesi in the Columbia–Snake River System could result in ecosystem level effects in areas intensively managed to improve conditions for salmon and other commercially and culturally important fish species. 

  7. Cymbopogon citratus-synthesized gold nanoparticles boost the predation efficiency of copepod Mesocyclops aspericornis against malaria and dengue mosquitoes.

    PubMed

    Murugan, Kadarkarai; Benelli, Giovanni; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Jeyalalitha, Tirupathi; Dinesh, Devakumar; Nicoletti, Marcello; Hwang, Jiang-Shiou; Suresh, Udaiyan; Madhiyazhagan, Pari

    2015-06-01

    Plant-borne compounds can be employed to synthesize mosquitocidal nanoparticles that are effective at low doses. However, how they affect the activity of mosquito predators in the aquatic environment is unknown. In this study, we synthesized gold nanoparticles (AuN) using the leaf extract of Cymbopogon citratus, which acted as a reducing and capping agent. AuN were characterized by a variety of biophysical methods and sorted for size in order to confirm structural integrity. C. citratus extract and biosynthesized AuN were tested against larvae and pupae of the malaria vector Anopheles stephensi and the dengue vector Aedes aegypti. LC₅₀ of C. citratus extract ranged from 219.32 ppm to 471.36 ppm. LC₅₀ of AuN ranged from 18.80 ppm to 41.52 ppm. In laboratory, the predatory efficiency of the cyclopoid crustacean Mesocyclops aspericornis against A. stephensi larvae was 26.8% (larva I) and 17% (larva II), while against A. aegypti was 56% (I) and 35.1% (II). Predation against late-instar larvae was minimal. In AuN-contaminated environment,predation efficiency against A. stephensi was 45.6% (I) and 26.7% (II), while against A. aegypti was 77.3% (I) and 51.6% (II). Overall, low doses of AuN may help to boost the control of Anopheles and Aedes larval populations in copepod-based control programs. PMID:25819295

  8. Choreographed swimming of copepod nauplii.

    PubMed

    Lenz, Petra H; Takagi, Daisuke; Hartline, Daniel K

    2015-11-01

    Small metazoan paddlers, such as crustacean larvae (nauplii), are abundant, ecologically important and active swimmers, which depend on exploiting viscous forces for locomotion. The physics of micropaddling at low Reynolds number was investigated using a model of swimming based on slender-body theory for Stokes flow. Locomotion of nauplii of the copepod Bestiolina similis was quantified from high-speed video images to obtain precise measurements of appendage movements and the resulting displacement of the body. The kinematic and morphological data served as inputs to the model, which predicted the displacement in good agreement with observations. The results of interest did not depend sensitively on the parameters within the error of measurement. Model tests revealed that the commonly attributed mechanism of 'feathering' appendages during return strokes accounts for only part of the displacement. As important for effective paddling at low Reynolds number is the ability to generate a metachronal sequence of power strokes in combination with synchronous return strokes of appendages. The effect of feathering together with a synchronous return stroke is greater than the sum of each factor individually. The model serves as a foundation for future exploration of micropaddlers swimming at intermediate Reynolds number where both viscous and inertial forces are important. PMID:26490629

  9. The microbiome of North Sea copepods

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  10. Ocean acidification challenges copepod reproductive plasticity

    NASA Astrophysics Data System (ADS)

    Vehmaa, A.; Almén, A.-K.; Brutemark, A.; Paul, A.; Riebesell, U.; Furuhagen, S.; Engström-Öst, J.

    2015-11-01

    Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia bifilosa in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ~ 365-1231 μatm), and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal if transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female copepod size and egg hatching success. In addition, we found a threshold of fCO2 concentration (~ 1000 μatm), above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon ~ 55 μm) or quality (C : N) weakens the transgenerational effects. However, females with high ORAC produced eggs with high hatching success. Overall, these results indicate that A. bifilosa could be affected by projected near future CO2 levels.

  11. Algal toxins alter copepod feeding behavior.

    PubMed

    Hong, Jiarong; Talapatra, Siddharth; Katz, Joseph; Tester, Patricia A; Waggett, Rebecca J; Place, Allen R

    2012-01-01

    Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepod's feeding appendages-a "sampling beating" that has short durations (<100 ms) and involves little fluid entrainment and a longer duration "grazing beating" that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepod's grazing behavior. These findings add critical insight into how these algal toxins may influence the copepod's feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods. PMID:22629336

  12. Video Plankton Recorder estimates of copepod, pteropod and larvacean distributions from a stratified region of Georges Bank with comparative measurements from a MOCNESS sampler

    NASA Astrophysics Data System (ADS)

    Benfield, Mark C.; Davis, Cabell S.; Wiebe, Peter H.; Gallager, Scott M.; Gregory Lough, R.; Copley, Nancy J.

    A two-vessel exercise was conducted over the southern flank of Georges Bank during the onset of vernal stratification in May 1992. The Video Plankton Recorder (VPR), a towed video system, was used to map out the fine-scale distributions of zooplankton to a depth of 70 m along a trackline which described a regular grid (3.5 4.5 km) in Lagrangian space. A second vessel following a parallel course conducted Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) sampling during the last section of the grid, which provided an opportunity to compare data from the two systems. Both the VPR and the MOCNESS provided similar data on the taxonomic composition of the plankton which was numerically dominated by copepods ( Calanus, Pseudocalanus, Oithona), pteropods ( Limacina) and larvaceans ( Oikopleura). The absence of rare (<43.1 m -3) species from the VPR dataset was a consequence of the small volume sampled (0.0694 m 3) by the high magnification camera, while fragile gelatinous taxa were undersampled by the MOCNESS. Estimates of copepod and pteropod concentrations were comparable for the two gear types. While the species composition of the plankton did not change statistically along the grid, abundances of the dominant taxa varied along the transect and each taxon demonstrated pronounced fine-scale vertical patterns that appeared to be related to hydrographic features. The VPR represents a powerful tool for rapid surveys of the micro- to fine-scale structure of zooplankton assemblages either alone, or in conjunction with other sampling techniques.

  13. Computational analysis and functional expression of ancestral copepod luciferase.

    PubMed

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

    2013-10-10

    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

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

    PubMed Central

    Isari, Stamatina; Antό, Meritxell; Saiz, Enric

    2013-01-01

    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

  15. Photoprotection by carotenoid pigments in the copepod Diaptomus nevadensis.

    PubMed Central

    Hairston, N C

    1976-01-01

    Individuals of the copepod Diaptomus nevadensis that contain high concentrations of carotenoids survive significantly better in natural intensities of visible light than less pigmented copepods. Vertical migration and behavior in light of different wave lengths are related to the degree of pigmentation. PMID:1062811

  16. Bacteria Associated with the Surface and Gut of Marine Copepods

    PubMed Central

    Sochard, M. R.; Wilson, D. F.; Austin, B.; Colwell, R. R.

    1979-01-01

    Little is known about the nature of bacteria associated with the surface and gut of marine copepods, either in laboratory-reared animals or in the natural environment. Nor is it known whether such animals possess a gut flora. The present report deals with studies of microorganisms isolated from healthy, laboratory-reared copepods of the species Acartia tonsa Dana, from several species of wild copepods collected from a marine or estuarine environment, and from laboratory dishes containing moribund copepods. Evidence for a unique gut flora in laboratory-reared animals is presented; the predominant bacteria were represented by the genus Vibrio. Other organisms such as Pseudomonas and Cytophaga were found less abundantly associated with the copepods and not specifically associated with the gut. Images PMID:16345368

  17. Mesozooplankton of the Arabian Sea: Patterns influenced by seasons, upwelling, and oxygen concentrations

    NASA Astrophysics Data System (ADS)

    Smith, S. L.; Madhupratap, M.

    2005-05-01

    The intensive study of the Arabian Sea during the 1990s included mesozooplankton investigations by the Netherlands, United Kingdom, Pakistan, India, Germany and the United States. Several major discoveries resulted. First, the high biomass of mesozooplankton observed during the Northeast Monsoon season is sustained by primary productivity stimulated by convective mixing and by an active microbial loop. The apparent paradox of high standing stocks of mesozooplankton coinciding with low standing stocks of phytoplankton thus was resolved. Second, the Southwest Monsoon (upwelling) season supports a burst of mesozooplankton growth, much of which is exported to the interior of the Arabian Sea by strong currents and eddy activity and to depth at the end of the season when diapause causes at least one very abundant copepod to leave the epipelagic zone. Third, the oxygen minimum zone severely restricts the vertical distribution of mesozooplankton in the eastern region of the Arabian Sea. The copepod that withstands conditions in the OMZ most readily, Pleuromamma indica, has increased in abundance over the past thirty years suggesting the OMZ may have grown in size and/or intensity in that time. Fourth, the Fall Intermonsoon and Northeast Monsoon seasons are characterized everywhere by increased abundance of the cyclopoid copepod genus, Oithona. Abundances of Oithona measured in the 1990s are much higher than those of the 1930s, suggesting food web alterations over the past half-century.

  18. Copepod Trajectory Characteristics in Thin Layers of Toxic Algal Exudates

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; True, A. C.; Weissburg, M. J.; Yen, J.

    2013-11-01

    Recently documented thin layers of toxic phytoplankton (``cryptic blooms'') are modeled in a custom flume system for copepod behavioral assays. Planar laser-induced fluorescence (LIF) measurements quantify the spatiotemporal structure of the chemical layers ensuring a close match to in situ bloom conditions and allowing for quantification of threshold dissolved toxin levels that induce behavioral responses. Assays with the copepods Acartia tonsa (hop-sinker) and Temora longicornis (cruiser) in thin layers of toxic exudates from the common dinoflagellate Karenia brevis (cell equivalent ~ 1 - 10,000 cells/mL) examine the effects of dissolved toxic compounds and copepod species on swimming trajectory characteristics. Computation of parameters such as swimming speed and the fractal dimension of the two-dimensional trajectory (F2D) allows for statistical evaluation of copepod behavioral responses to dissolved toxic compounds associated with harmful algal blooms (HABs). Changes in copepod swimming behavior caused by toxic compounds can significantly influence predator, prey, and mate encounter rates by altering the fracticality (``diffuseness'' or ``volume-fillingness'') of a copepod's trajectory. As trophic mediators linking primary producers and higher trophic levels, copepods can significantly influence HAB dynamics and modulate large scale ecological effects through their behavioral interactions with toxic blooms.

  19. Molecular and microscopic evidence of viruses in marine copepods.

    PubMed

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

    2013-01-22

    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 10(5) 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

  20. Interannual variation in diapausing copepods and associated water masses in a continental shelf basin, and implications for copepod buoyancy

    NASA Astrophysics Data System (ADS)

    Davies, Kimberley T. A.; Taggart, Christopher T.; Smedbol, R. Kent

    2015-11-01

    Oceanographic surveys were conducted in Roseway Basin, western Scotian Shelf, during late-summer from 2007 through 2009 to measure the magnitude of interannual variation in the spatial distribution of diapausing copepods Calanus finmarchicus and C. hyperboreus and associated water mass characteristics. Calanus spp. abundance, energy density and hydrography were measured at depths > 50 m along transects using a Towed Underwater Biological Sampling System equipped with an Optical Plankton Counter (OPC) and a conductivity-temperature-depth (CTD) sensor, as well as at fixed stations using a Biological Net and Environmental Sampling System equipped with nets, OPC and CTD. Water mass density and in some cases salinity explained variation in the deep copepod layer across both time and space, whereas temperature did not. Water mass density, copepod energy density and thickness of the copepod layer were statistically lower during 2008 than 2007 or 2009. The copepod layer was absent from the western Basin margin during 2008 where low density continental water resided that year, whereas during 2007 and 2009 higher density continental slope water and copepods were each present along the western margin. Our results suggest that water mass density is an important characteristic defining the spatial and interannual ecology of the deep copepod layer in Roseway Basin. The 26 σt isopycnal may be a lower density limit to diapausing Calanus spp. habitat on continental shelves with shallow bathymetry, that helps the animals maintain neutral buoyancy during diapause.

  1. Differential dormancy of co-occurring copepods

    NASA Astrophysics Data System (ADS)

    Ohman, Mark D.; Drits, Aleksandr V.; Elizabeth Clarke, M.; Plourde, Stéphane

    1998-08-01

    Four species of planktonic calanoid copepods that co-occur in the California Current System ( Eucalanus californicus Johnson, Rhincalanus nasutus Giesbrecht, Calanus pacificus californicus Brodsky, and Metridia pacifica Brodsky) were investigated for evidence of seasonal dormancy in the San Diego Trough. Indices used to differentiate actively growing from dormant animals included developmental stage structure and vertical distribution; activity of aerobic metabolic enzymes (Citrate Synthase and the Electron Transfer System complex); investment in depot lipids (wax esters and triacylglycerols); in situ grazing activity from gut fluorescence; and egg production rates in simulated in situ conditions. None of the 4 species exhibited a canonical calanoid pattern of winter dormancy - i.e., synchronous developmental arrest as copepodid stage V, descent into deep waters, reduced metabolism, and lack of winter reproduction. Instead, Calanus pacificus californicus has a biphasic life history in this region, with an actively reproducing segment of the population in surface waters overlying a deep dormant segment in winter. Eucalanus californicus is dormant as both adult females and copepodid V's, although winter females respond relatively rapidly to elevated food and temperature conditions; they begin feeding and producing eggs within 2-3 days. Rhincalanus nasutus appears to enter dormancy as adult females, although the evidence is equivocal. Metridia pacifica shows no evidence of dormancy, with sustained active feeding, diel vertical migration behavior, and elevated activity of metabolic enzymes in December as well as in June. The four species also differ markedly in water content, classes of storage lipids, and specific activity of Citrate Synthase. These results suggest that copepod dormancy traits and structural composition reflect diverse adaptations to regional environmental conditions rather than a uniform, canonical series of traits that remain invariant among taxa and fixed across a species' range. Such interspecific and regional differences in life history traits need to be incorporated in models simulating Eastern Boundary Current pelagic ecosystem dynamics.

  2. Identifying copepod functional groups from species functional traits

    PubMed Central

    Benedetti, Fabio; Gasparini, Stéphane; Ayata, Sakina-Dorothée

    2016-01-01

    We gathered information on the functional traits of the most representative copepod species in the Mediterranean Sea. Our database includes 191 species described by 7 traits encompassing diverse ecological functions: minimal and maximal body length, trophic group, feeding type, spawning strategy, diel vertical migration and vertical habitat. Cluster analysis in the functional trait space revealed that Mediterranean copepods can be separated into groups with distinct ecological roles. PMID:26811565

  3. Copepod Population-Specific Response to a Toxic Diatom Diet

    PubMed Central

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

    2012-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2006-07-01

    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 method was applied to study the occurrence of dead copepods along the York River and the Hampton River in the lower Chesapeake Bay during June-July, 2005. The zooplankton community was dominated by copepods; on average 29% of the copepod population appeared dead. Recovery of percent dead copepods did not differ between horizontal tows and vertical tows, suggesting that dead copepods were homogenously distributed in the water column. No significant relationship was found between the percent dead copepods and surface water temperature, salinity, Secchi depth or chlorophyll concentration. In laboratory experiments, dead copepods were decomposed by ambient bacteria and the rate of decomposition was temperature-dependent. Combining field and laboratory results we estimated that the non-consumptive mortality (mortality not due to predation) of copepods in the lower Chesapeake Bay was 0.12 d -1 under steady-state condition, which is within the global average of copepod mortality rate.

  5. Copepods' Response to Burgers' Vortex: Deconstructing Interactions of Copepods with Turbulence.

    PubMed

    Webster, D R; Young, D L; Yen, J

    2015-10-01

    This study examined the behavioral response of two marine copepods, Acartia tonsa and Temora longicornis, to a Burgers' vortex intended to mimic the characteristics of a turbulent vortex that a copepod is likely to encounter in the coastal or near-surface zone. Behavioral assays of copepods were conducted for two vortices that correspond to turbulent conditions with mean dissipation rates of turbulence of 0.009 and 0.096 cm(2) s(-3) (denoted turbulence level 2 and level 3, respectively). In particular, the Burgers' vortex parameters (i.e., circulation and rate of axial strain rate) were specified to match a vortex corresponding to the median rate of dissipation due to viscosity for each target level of turbulence. Three-dimensional trajectories were quantified for analysis of swimming kinematics and response to hydrodynamic cues. Acartia tonsa did not significantly respond to the vortex corresponding to turbulence level 2. In contrast, A. tonsa significantly altered their swimming behavior in the turbulence-level-3 vortex, including increased relative speed of swimming, angle of alignment of the trajectory with the axis of the vortex, ratio of net-to-gross displacement, and acceleration during escape, along with decreased turn frequency (relative to stagnant control conditions). Further, the location of A. tonsa escapes was preferentially in the core of the stronger vortex, indicating that the hydrodynamic cue triggering the distinctive escape behavior was vorticity. In contrast, T. longicornis did not reveal a behavioral response to either the turbulence level 2 or the level 3 vortex. PMID:26002348

  6. History repeats itself: genomic divergence in copepods.

    PubMed

    Renaut, Sébastien; Dion-Côté, Anne-Marie

    2016-04-01

    Press stop, erase everything from now till some arbitrary time in the past and start recording life as it evolves once again. Would you see the same tape of life playing itself over and over, or would a different story unfold every time? The late Steven Jay Gould called this experiment replaying the tape of life and argued that any replay of the tape would lead evolution down a pathway radically different from the road actually taken (Gould 1989). This thought experiment has puzzled evolutionary biologists for a long time: how repeatable are evolutionary events? And if history does indeed repeat itself, what are the factors that may help us predict the path taken? A powerful means to address these questions at a small evolutionary scale is to study closely related populations that have evolved independently, under similar environmental conditions. This is precisely what Pereira et al. () set out to do using marine copepods Tigriopus californicus, and present their results in this issue of Molecular Ecology. They show that evolution can be repeatable and even partly predictable, at least at the molecular level. As expected from theory, patterns of divergence were shaped by natural selection. At the same time, strong genetic drift due to small population sizes also constrained evolution down a similar evolutionary road, and probably contributed to repeatable patterns of genomic divergence. PMID:27012819

  7. Spectral sensitivity of vertically migrating marine copepods.

    PubMed

    Cohen, Jonathan H; Forward, Richard B

    2002-12-01

    Light is a critical factor in the proximate basis of diel vertical migration (DVM) in zooplankton. A photobehavioral approach was used to examine the spectral sensitivity of four coastal species of calanoid copepod, representing a diversity of DVM patterns, to test whether species that migrate (nocturnal or reverse DVM) have response spectra that differ from non-migratory surface dwellers. The following species were given light stimuli at wavelengths from 350 to 740 nm, and their photoresponses were measured: Centropages typicus (nocturnal migrator), Calanopia americana (nocturnal migrator), Anomalocera ornata (reverse migrator), and Labidocera aestiva (non-migrator). Centropages typicus and A. ornata had peak responses at 500 and 520 nm, respectively, while Calanopia americana had maximum responses at 480 and 520 nm. Thus, the species that undergo DVM have peak photobehavioral responses at wavelengths corresponding to those available during twilight in coastal water, although the range of wavelengths to which they respond is variable. Non-migratory surface-dwelling L. aestiva had numerous response peaks over a broad spectral range, which may serve to maximize photon capture for vision in their broad-spectrum shallow-water habitat. PMID:12480721

  8. Hydrocarbon Contamination Decreases Mating Success in a Marine Planktonic Copepod

    PubMed Central

    Seuront, Laurent

    2011-01-01

    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

  9. What Copepods Can Tell us About Epikarst Hydrology

    NASA Astrophysics Data System (ADS)

    Culver, D. C.; Pipan, T.

    2008-05-01

    Epikarst, the skin of karst, is a complex structure with numerous cracks, fissures, and solution cavities. It is a poorly integrated aquifer in both horizontal and vertical dimensions. Nearly the only way to investigate epikarst water has been by collecting water dripping out of epikarst. Even drips a few meters away often have significant differences in water chemistry. Yes there is also significant lateral transmission of water as evidence by lateral movement of contaminant spills in epikarst. A diverse copepod fauna occurs in epikarst, and because of their minute size are in general at the mercy of water currents. We investigated whether they could be used as natural tracers to delineate subsurface drainage basins. We determined the distributions of 27 copepod species in 35 drips in four Slovenian caves (Dimnice, Postojna Planina Cave System, Skocjanske Jame, Supanova Jama) and ten species from 13 drips in one U.S. cave (Organ Cave, W.Va.). A significant fraction of the copepod species found (9 in Slovenian and 3 in West Virginia) occurred over a maximum linear extent of 100 m. These and other localized distributions probably resulted from colonization of epikarst by an ancestral surface population in a single location, with subsequent lateral spread in the direction of epikarst flow. This suggests that the distribution of copepods could potentially be used to trace major flow paths in epikarst without the need for the injection of dyes or other tracers. The genetic structure of copepod metapopulations is also of considerable interest.

  10. Gene expression patterns and stress response in marine copepods.

    PubMed

    Lauritano, Chiara; Procaccini, Gabriele; Ianora, Adrianna

    2012-05-01

    Aquatic organisms are constantly exposed to both physical (e.g. temperature and salinity variations) and chemical (e.g. endocrine disruptor chemicals, heavy metals, hydrocarbons, diatom toxins, and other toxicants) stressors which they react to by activating a series of defense mechanisms. This paper reviews the literature on the defense systems, including detoxification enzymes and proteins (e.g. glutathione S-transferases, heat shock proteins, superoxide dismutase and catalase), studied in copepods at the molecular level. The data indicate high inter- and intra-species variability in copepod response, depending on the type of stressor tested, the concentration and exposure time, and the enzyme isoform studied. Ongoing -omics approaches will allow the identification of new genes which will give a more comprehensive overview of how copepods respond to specific stressors in laboratory and/or field conditions and the effects of these responses on higher trophic levels. PMID:22030210

  11. Rapid Enzymatic Response to Compensate UV Radiation in Copepods

    PubMed Central

    Souza, Mara Sol; Hansson, Lars-Anders; Hylander, Samuel; Modenutti, Beatriz; Balseiro, Esteban

    2012-01-01

    Ultraviolet radiation (UVR) causes physical damage to DNA, carboxylation of proteins and peroxidation of lipids in copepod crustaceans, ubiquitous and abundant secondary producers in most aquatic ecosystems. Copepod adaptations for long duration exposures include changes in behaviour, changes in pigmentation and ultimately changes in morphology. Adaptations to short-term exposures are little studied. Here we show that short-duration exposure to UVR causes the freshwater calanoid copepod, Eudiaptomus gracilis, to rapidly activate production of enzymes that prevent widespread collateral peroxidation (glutathione S-transferase, GST), that regulate apoptosis cell death (Caspase-3, Casp-3), and that facilitate neurotransmissions (cholinesterase-ChE). None of these enzyme systems is alone sufficient, but they act in concert to reduce the stress level of the organism. The interplay among enzymatic responses provides useful information on how organisms respond to environmental stressors acting on short time scales. PMID:22384136

  12. Sensitivity of hypogean and epigean freshwater copepods to agricultural pollutants.

    PubMed

    Di Lorenzo, T; Di Marzio, W D; Senz, M E; Baratti, M; Dedonno, A A; Iannucci, A; Cannicci, S; Messana, G; Galassi, D M P

    2014-03-01

    Widespread pollution from agriculture is one of the major causes of the poor freshwater quality currently observed across Europe. Several studies have addressed the direct impact of agricultural pollutants on freshwater biota by means of laboratory bioassays; however, as far as copepod crustaceans are concerned, the ecotoxicological research is scarce for freshwater species and almost nonexistent for the hypogean ones. In this study, we conducted a comparative analysis of the available literature data on the sensitivity of freshwater copepods to agricultural pollutants. We also assessed the acute and chronic sensitivity of a hypogean and an epigean species, both belonging to the Crustacea Copepoda Cyclopoida Cyclopidae, to two N-fertilizers (urea and ammonium nitrate) and two herbicides (ARIANE(TM) II from Dow AgroSciences LLC, and Imazamox), widely used for cereal agriculture in Europe. According to the literature review, freshwater copepods are sensitive to a range of pesticides and N-fertilizers. Ecotoxicological studies on hypogean species of copepods account only one study. There are no standardized protocols available for acute and chronic toxicity tests for freshwater copepods, making comparisons about sensitivity difficult. From our experiments, ionized ammonia proved to be more toxic than the herbicide Imazamox, in both short and chronic bioassays. Urea was the less toxic chemical for both species. The hypogean species was more sensitive than the epigean one to all chemicals. For both species and for all tested chemicals, acute lethality and chronic lethality were induced at concentrations higher than the law limits of good water body quality in Europe, except for ionized ammonia, which provoked the chronic lethality of the hypogean species at a lower concentration. The hazardous concentration (HC) of un-ionized ammonia for 5 % of freshwater copepods, obtained by a species sensitivity distribution, was 92 ?g l(-1), significantly lower than the HC computed for traditional test species from freshwater environments. PMID:24352541

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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 m. 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.

  14. Interactions between benthic copepods, bacteria and diatoms promote nitrogen retention in intertidal marine sediments.

    PubMed

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

    2014-01-01

    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

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

    PubMed Central

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

    2014-01-01

    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

  16. Nitrogen-fixing bacteria associated with copepods in coastal waters of the North Atlantic Ocean.

    PubMed

    Scavotto, Rosemary E; Dziallas, Claudia; Bentzon-Tilia, Mikkel; Riemann, Lasse; Moisander, Pia H

    2015-10-01

    The community composition of N2 -fixing microorganisms (diazotrophs) was investigated in copepods (primarily Acartia spp.) in parallel to that of seawater in coastal waters off Denmark (Øresund) and New England, USA. The unicellular cyanobacterial diazotroph UCYN-A was detected from seawater and full-gut copepods, suggesting that the new N contributed by UCYN-A is directly transferred to higher trophic levels in these waters. Deltaproteobacterial and Cluster 3 nifH sequences were detected in > 1 μm seawater particles and full-gut copepods, suggesting that they associate with copepods primarily via feeding. The dominant communities in starved copepods were Vibrio spp. and related Gammaproteobacteria, suggesting they represent the most permanent diazotroph associations in the copepods. N2 fixation rates were up to 3.02 pmol N copepod(-1) day(-1). Although at a typical copepod density in estuarine waters, these volumetric rates are low; considering the small size of a copepod, these mesozooplanktonic crustaceans may serve as hotspots of N2 fixation, at 12.9-71.9 μmol N dm(-3) copepod biomass day(-1). Taken together, diazotroph associations range from more permanent attachments to copepod feeding on some groups. Similar diazotroph groups detected on the eastern and western Atlantic Ocean suggest that these associations are a general phenomenon and play a role in the coastal N cycles. PMID:25655773

  17. Detecting In Situ Copepod Diet Diversity Using Molecular Technique: Development of a Copepod/Symbiotic Ciliate-Excluding Eukaryote-Inclusive PCR Protocol

    PubMed Central

    Li, Tao; Carpenter, Edward J.; Liu, Sheng; Lin, Senjie

    2014-01-01

    Knowledge of in situ copepod diet diversity is crucial for accurately describing pelagic food web structure but is challenging to achieve due to lack of an easily applicable methodology. To enable analysis with whole copepod-derived DNAs, we developed a copepod-excluding 18S rDNA-based PCR protocol. Although it is effective in depressing amplification of copepod 18S rDNA, its applicability to detect diverse eukaryotes in both mono- and mixed-species has not been demonstrated. Besides, the protocol suffers from the problem that sequences from symbiotic ciliates are overrepresented in the retrieved 18S rDNA libraries. In this study, we designed a blocking primer to make a combined primer set (copepod/symbiotic ciliate-excluding eukaryote-common: CEEC) to depress PCR amplification of symbiotic ciliate sequences while maximizing the range of eukaryotes amplified. We firstly examined the specificity and efficacy of CEEC by PCR-amplifying DNAs from 16 copepod species, 37 representative organisms that are potential prey of copepods and a natural microplankton sample, and then evaluated the efficiency in reconstructing diet composition by detecting the food of both lab-reared and field-collected copepods. Our results showed that the CEEC primer set can successfully amplify 18S rDNA from a wide range of isolated species and mixed-species samples while depressing amplification of that from copepod and targeted symbiotic ciliate, indicating the universality of CEEC in specifically detecting prey of copepods. All the predetermined food offered to copepods in the laboratory were successfully retrieved, suggesting that the CEEC-based protocol can accurately reconstruct the diets of copepods without interference of copepods and their associated ciliates present in the DNA samples. Our initial application to analyzing the food composition of field-collected copepods uncovered diverse prey species, including those currently known, and those that are unsuspected, as copepod prey. While testing is required, this protocol provides a useful strategy for depicting in situ dietary composition of copepods. PMID:25058323

  18. Novel organization and development of copepod myelin. ii. nonglial origin.

    PubMed

    Wilson, Caroline H; Hartline, Daniel K

    2011-11-01

    Nerve-impulse conduction is greatly speeded by myelin sheaths in vertebrates, oligochaete annelids, penaeid and caridean shrimp, and calanoid copepods. In the first three invertebrate cases, myelin arises from glial cells, as it does in vertebrates. The contribution of the glial cells to the layered structure of the myelin is clear: their nuclei are either embedded in the layers or reside in contiguous cytoplasmic compartments, and their cell membranes are seen to be continuous with those of the myelin layers. However, with calanoids, the association with glial cells presumed necessary to generate the myelin has never been satisfactorily identified. We have conducted a systematic examination of thin sections through different parts of the copepod nervous system to identify the structural organization of copepod myelin and the likely mechanism for its formation. We find that myelination appears to commence by laying down and compacting a cisternal tongue against the inside of the axolemma. This is followed by the successive layering and compaction of additional tongues to create a stack of tongues. The margins of the tongues then expand to encircle the interior of a neurite, meeting and fusing to form complete concentric myelin. No sign of glial involvement could be detected at any stage. Unlike glially derived myelin, the extracellular tracer lanthanum did not penetrate between the myelin layers in copepods, further evidence against a glial source. We believe this to be the first demonstration of a nonglial origin for myelin in any species. PMID:21674501

  19. New insights into the complex architecture of siliceous copepod teeth.

    PubMed

    Michels, Jan; Vogt, Jrgen; Simon, Paul; Gorb, Stanislav N

    2015-06-01

    Copepods belong to the dominant marine zooplankton taxa and play an important role in particle and energy fluxes of the marine water column. Their mandibular gnathobases possess tooth-like structures, so-called teeth. In species feeding on large proportions of diatoms these teeth often contain silica, which is very probably the result of a coevolution with the siliceous diatom frustules. Detailed knowledge of the morphology and composition of the siliceous teeth is essential for understanding their functioning and their significance in the context of feeding interactions between copepods and diatoms. Based on analyses of the gnathobases of the Antarctic copepod Rhincalanus gigas, the present study clearly shows, for the first time, that the silica in the siliceous teeth features large proportions of crystalline silica that is consistent with the mineral ?-cristobalite and is doped with aluminium. The siliceous structures have internal chitinous fibre networks, which are assumed to serve as scaffolds during the silicification process. The compact siliceous teeth of R. gigas are accompanied by structures with large proportions of the elastic protein resilin, likely reducing the mechanical damage of the teeth when the copepods feed on diatoms with very stable frustules. The results indicate that the coevolution with diatom frustules has resulted in gnathobases exhibiting highly sophisticated composite structures. PMID:25622509

  20. Ageing and Caloric Restriction in a Marine Planktonic Copepod

    PubMed Central

    Saiz, Enric; Calbet, Albert; Griffell, Kaiene; Bersano, José Guilherme F.; Isari, Stamatina; Solé, Montserrat; Peters, Janna; Alcaraz, Miquel

    2015-01-01

    Planktonic copepods are a key group in the marine pelagic ecosystem, linking primary production with upper trophic levels. Their abundance and population dynamics are constrained by the life history tradeoffs associated with resource availability, reproduction and predation pressure. The tradeoffs associated with the ageing process and its underlying biological mechanisms are, however, poorly known. Our study shows that ageing in copepods involves a deterioration of their vital rates and a rise in mortality associated with an increase in oxidative damage (lipid peroxidation); the activity of the cell-repair enzymatic machinery also increases with age. This increase in oxidative damage is associated with an increase in the relative content of the fatty acid 22:6(n-3), an essential component of cell membranes that increases their susceptibility to peroxidation. Moreover, we show that caloric (food) restriction in marine copepods reduces their age-specific mortality rates, and extends the lifespan of females and their reproductive period. Given the overall low production of the oceans, this can be a strategy, at least in certain copepod species, to enhance their chances to reproduce in a nutritionally dilute, temporally and spatially patchy environment. PMID:26455575

  1. Ageing and Caloric Restriction in a Marine Planktonic Copepod.

    PubMed

    Saiz, Enric; Calbet, Albert; Griffell, Kaiene; Bersano, Jos Guilherme F; Isari, Stamatina; Sol, Montserrat; Peters, Janna; Alcaraz, Miquel

    2015-01-01

    Planktonic copepods are a key group in the marine pelagic ecosystem, linking primary production with upper trophic levels. Their abundance and population dynamics are constrained by the life history tradeoffs associated with resource availability, reproduction and predation pressure. The tradeoffs associated with the ageing process and its underlying biological mechanisms are, however, poorly known. Our study shows that ageing in copepods involves a deterioration of their vital rates and a rise in mortality associated with an increase in oxidative damage (lipid peroxidation); the activity of the cell-repair enzymatic machinery also increases with age. This increase in oxidative damage is associated with an increase in the relative content of the fatty acid 22:6(n-3), an essential component of cell membranes that increases their susceptibility to peroxidation. Moreover, we show that caloric (food) restriction in marine copepods reduces their age-specific mortality rates, and extends the lifespan of females and their reproductive period. Given the overall low production of the oceans, this can be a strategy, at least in certain copepod species, to enhance their chances to reproduce in a nutritionally dilute, temporally and spatially patchy environment. PMID:26455575

  2. Dissolution of coccolithophorid calcite by microzooplankton and copepod grazing

    NASA Astrophysics Data System (ADS)

    Antia, A. N.; Suffrian, K.; Holste, L.; Mller, M. N.; Nejstgaard, J. C.; Simonelli, P.; Carotenuto, Y.; Putzeys, S.

    2008-01-01

    Independent of the ongoing acidification of surface seawater, the majority of the calcium carbonate produced in the pelagial is dissolved by natural processes above the lysocline. We investigate to what extent grazing and passage of coccolithophorids through the guts of copepods and the food vacuoles of microzooplankton contribute to calcite dissolution. In laboratory experiments where the coccolithophorid Emiliania huxleyi was fed to the rotifer Brachionus plicatilis, the heterotrophic flagellate Oxyrrhis marina and the copepod Acartia tonsa, calcite dissolution rates of 45-55%, 37-53% and 5-22% of ingested calcite were found. We ascribe higher loss rates in microzooplankton food vacuoles as compared to copepod guts to the strongly acidic digestion and the individual packaging of algal cells. In further experiments, specific rates of calcification and calcite dissolution were also measured in natural populations during the PeECE III mesocosm study under differing ambient pCO2 concentrations. Microzooplankton grazing accounted for between 27 and 70% of the dynamic calcite stock being lost per day, with no measurable effect of CO2 treatment. These measured calcite dissolution rates indicate that dissolution of calcite in the guts of microzooplankton and copepods can account for the calcite losses calculated for the global ocean using budget and model estimates.

  3. Ageing and Caloric Restriction in a Marine Planktonic Copepod

    NASA Astrophysics Data System (ADS)

    Saiz, Enric; Calbet, Albert; Griffell, Kaiene; Bersano, José Guilherme F.; Isari, Stamatina; Solé, Montserrat; Peters, Janna; Alcaraz, Miquel

    2015-10-01

    Planktonic copepods are a key group in the marine pelagic ecosystem, linking primary production with upper trophic levels. Their abundance and population dynamics are constrained by the life history tradeoffs associated with resource availability, reproduction and predation pressure. The tradeoffs associated with the ageing process and its underlying biological mechanisms are, however, poorly known. Our study shows that ageing in copepods involves a deterioration of their vital rates and a rise in mortality associated with an increase in oxidative damage (lipid peroxidation); the activity of the cell-repair enzymatic machinery also increases with age. This increase in oxidative damage is associated with an increase in the relative content of the fatty acid 22:6(n-3), an essential component of cell membranes that increases their susceptibility to peroxidation. Moreover, we show that caloric (food) restriction in marine copepods reduces their age-specific mortality rates, and extends the lifespan of females and their reproductive period. Given the overall low production of the oceans, this can be a strategy, at least in certain copepod species, to enhance their chances to reproduce in a nutritionally dilute, temporally and spatially patchy environment.

  4. KARYOLOGICAL STUDY OF THE CALANOID COPEPOD 'EURYTEMORA AFFINIS'

    EPA Science Inventory

    Chromosomes of the calanoid copepod Eurytemora affinis are described. The diploid chromosome number determined from cells at metaphase is twenty. There are ten pairs of metacentric chromosomes which can be divided into three size classes. No evidence of a heteromorphic chromosome...

  5. Interannual variability of copepods in a Mediterranean coastal area (Saronikos Gulf, Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Christou, Epaminondas D.

    1998-06-01

    Patterns of abundance of the dominant copepods as well as that of the total copepods, are given for a coastal area of the eastern Mediterranean Sea (Saronikos Gulf, Aegean Sea). The results were based on 124 zooplankton samples collected biweekly during a 5-year period from January 1989 through December 1993. Copepod abundances and environmental parameters, almost all, exhibited pronounced annual cycles. Most copepods revealed repeated patterns and considerable interannual variability. Both salinity and abundance of total copepods, revealed a clear interannual increase from 1989 to 1993. Multiple regression models, based on stepwise variable selection, suggested that temperature and salinity were the most significant environmental parameters accounting for the variability of abundances. Simple regression models applied on mean annual values reveal the importance of salinity as the most significant factor affecting interannual variability of copepods.

  6. A New Toxicity Test Using the Freshwater Copepod Cyclops vernalis.

    PubMed

    Marus, Emma M; Elphick, James R; Bailey, Howard C

    2015-09-01

    The cladocerans Ceriodaphnia dubia and Daphnia magna are widely used in environmental toxicity testing and the test methodologies for these species are well developed. However, copepods are a much more abundant contributor to zooplankton in many lakes, but they are not routinely used in toxicity tests. Therefore, we propose toxicity test methods for the freshwater copepod, Cyclops vernalis assessing effects on its survival and growth. A case study is presented in which the proposed test was performed with a range of concentrations of total dissolved solids (TDS) and used as part of a test battery to develop a site-specific water quality objective. C. vernalis was less sensitive to TDS compared to D. magna and C. dubia, but similarly sensitive to an alga, a diatom, a rotifer, a chironomid, and two fish species. No adverse effects were observed on survival or growth of C. vernalis at TDS concentrations up to 1500 mg/L. PMID:26183385

  7. Copepods induce paralytic shellfish toxin production in marine dinoflagellates

    PubMed Central

    Selander, Erik; Thor, Peter; Toth, Gunilla; Pavia, Henrik

    2006-01-01

    Among the thousands of unicellular phytoplankton species described in the sea, some frequently occurring and bloom-forming marine dinoflagellates are known to produce the potent neurotoxins causing paralytic shellfish poisoning. The natural function of these toxins is not clear, although they have been hypothesized to act as a chemical defence towards grazers. Here, we show that waterborne cues from the copepod Acartia tonsa induce paralytic shellfish toxin (PST) production in the harmful algal bloom-forming dinoflagellate Alexandrium minutum. Induced A. minutum contained up to 2.5 times more toxins than controls and was more resistant to further copepod grazing. Ingestion of non-toxic alternative prey was not affected by the presence of induced A. minutum. The ability of A. minutum to sense and respond to the presence of grazers by increased PST production and increased resistance to grazing may facilitate the formation of harmful algal blooms in the sea. PMID:16769640

  8. The assimilation of elements ingested by marine copepods

    SciTech Connect

    Reinfelder, J.R.; Fisher, N.S. )

    1991-02-15

    The efficiency with which a variety of ingested elements (Ag, Am, C, Cd, P, S, Se, and Zn) were assimilated in marine calanoid copepods fed uniformly radiolabeled diatoms ranged from 0.9% for Am to 97.1% for Se. Assimilation efficiencies were directly related to the cytoplasmic content of the diatoms. This relation indicates that the animals obtained nearly all their nutrition from this source. The results suggest that these zooplankton, which have short gut residence times, have developed a gut lining and digestive strategy that provides for assimilation of only soluble material. Because the fraction of total cellular protein in the cytoplasm of the diatoms increased markedly with culture age, copepods feeding on senescent cells should obtain more protein than those feeding on rapidly dividing cells. Elements that are appreciably incorporated into algal cytoplasm and assimilated in zooplankton should be recycled in surface waters and have longer oceanic residence times than elements bound to cell surfaces.

  9. Stable Associations Masked by Temporal Variability in the Marine Copepod Microbiome

    PubMed Central

    Moisander, Pia H.; Sexton, Andrew D.; Daley, Meaghan C.

    2015-01-01

    Copepod-bacteria interactions include permanent and transient epi- and endobiotic associations that may play roles in copepod health, transfer of elements in the food web, and biogeochemical cycling. Microbiomes of three temperate copepod species (Acartia longiremis, Centropages hamatus, and Calanus finmarchicus) from the Gulf of Maine were investigated during the early summer season using high throughput amplicon sequencing. The most prominent stable component of the microbiome included several taxa within Gammaproteobacteria, with Pseudoalteromonas spp. especially abundant across copepod species. These Gammaproteobacteria appear to be promoted by the copepod association, likely benefitting from nutrient enriched microenvironments on copepods, and forming a more important part of the copepod-associated community than Vibrio spp. during the cold-water season in this temperate system. Taxon-specific associations included an elevated relative abundance of Piscirickettsiaceae and Colwelliaceae on Calanus, and Marinomonas sp. in Centropages. The communities in full and voided gut copepods had distinct characteristics, thus the presence of a food-associated microbiome was evident, including higher abundance of Rhodobacteraceae and chloroplast sequences in the transient communities. The observed variability was partially explained by collection date that may be linked to factors such as variable time since molting, gender differences, and changes in food availability and type over the study period. While some taxon-specific and stable associations were identified, temporal changes in environmental conditions, including food type, appear to be key in controlling the composition of bacterial communities associated with copepods in this temperate coastal system during the early summer. PMID:26393930

  10. Complex trophic interactions of calanoid copepods in the Benguela upwelling system

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  11. Host-Specific and pH-Dependent Microbiomes of Copepods in an Extensive Rearing System.

    PubMed

    Skovgaard, Alf; Castro-Mejia, Josue Leonardo; Hansen, Lars Hestbjerg; Nielsen, Dennis Sandris

    2015-01-01

    Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, harmful algae, or other eukaryotes and prokaryotes that may be non-beneficial for the copepods. In this study, the composition of bacteria associated with copepods was investigated in an extensive outdoor copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) analysis, a clear difference was found between the microbiomes of the two copepod species, Acartia tonsa and Centropages hamatus, present in the system. This pattern was corroborated through 454/FLX-based 16S rRNA gene amplicon sequencing of copepod microbiomes, which furthermore showed that the abiotic parameters pH and oxygen concentration in rearing tank water were the key factors influencing composition of copepod microbiomes. PMID:26167852

  12. Host-Specific and pH-Dependent Microbiomes of Copepods in an Extensive Rearing System

    PubMed Central

    Skovgaard, Alf; Castro-Mejia, Josue Leonardo; Hansen, Lars Hestbjerg; Nielsen, Dennis Sandris

    2015-01-01

    Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, harmful algae, or other eukaryotes and prokaryotes that may be non-beneficial for the copepods. In this study, the composition of bacteria associated with copepods was investigated in an extensive outdoor copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) analysis, a clear difference was found between the microbiomes of the two copepod species, Acartia tonsa and Centropages hamatus, present in the system. This pattern was corroborated through 454/FLX-based 16S rRNA gene amplicon sequencing of copepod microbiomes, which furthermore showed that the abiotic parameters pH and oxygen concentration in rearing tank water were the key factors influencing composition of copepod microbiomes. PMID:26167852

  13. Global latitudinal variations in marine copepod diversity and environmental factors.

    PubMed

    Rombouts, Isabelle; Beaugrand, Grgory; Ibanez, Frdric; Gasparini, Stphane; Chiba, Sanae; Legendre, Louis

    2009-09-01

    Latitudinal gradients in diversity are among the most striking features in ecology. For terrestrial species, climate (i.e. temperature and precipitation) is believed to exert a strong influence on the geographical distributions of diversity through its effects on energy availability. Here, we provide the first global description of geographical variation in the diversity of marine copepods, a key trophic link between phytoplankton and fish, in relation to environmental variables. We found a polar-tropical difference in copepod diversity in the Northern Hemisphere where diversity peaked at subtropical latitudes. In the Southern Hemisphere, diversity showed a tropical plateau into the temperate regions. This asymmetry around the Equator may be explained by climatic conditions, in particular the influence of the Inter-Tropical Convergence Zone, prevailing mainly in the northern tropical region. Ocean temperature was the most important explanatory factor among all environmental variables tested, accounting for 54 per cent of the variation in diversity. Given the strong positive correlation between diversity and temperature, local copepod diversity, especially in extra-tropical regions, is likely to increase with climate change as their large-scale distributions respond to climate warming. PMID:19515670

  14. Contrasting Ecosystem-Effects of Morphologically Similar Copepods

    PubMed Central

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

    2011-01-01

    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

  15. Fish immune responses to parasitic copepod (namely sea lice) infection.

    PubMed

    Fast, Mark D

    2014-04-01

    Parasitic copepods, in particular sea lice, have considerable impacts upon global freshwater and marine fisheries, with major economic consequences recognized primarily in aquaculture. Sea lice have been a contentious issue with regards to interactions between farmed and wild populations of fish, in particular salmonids, and their potential for detrimental effects at a population level. The following discussion will pertain to aquatic parasitic copepod species for which we have significant information on the host-parasite interaction and host response to infection (Orders Cyclopoida, Poecilostomatoida and Siphonostomatoida). This review evaluates prior research in terms of contributions to understanding parasite stage specific responses by the host, and in many cases draws upon model organisms like Lepeophtheirus salmonis and Atlantic salmon to convey important concepts in fish responses to parasitic copepod infection. The article discusses TH1 and TH2-like host responses in light of parasite immunomodulation of the host, current methods of immunological stimulation and where the current and future work in this field is heading. PMID:24001580

  16. Copepod communities along an Atlantic Meridional Transect: Abundance, size structure, and grazing rates

    NASA Astrophysics Data System (ADS)

    Lpez, Eva; Anadn, Ricardo

    2008-10-01

    Large-scale variability in copepod abundance, size structure, and ingestion rates on phytoplankton was investigated during the cruise Atlantic Meridional Transect-13. The main aim of the study was to assess the relative importance of small copepods and copepod nauplii in different regions (Temperate N and S, Oligotrophic N and S, Equatorial and Mauritanian upwelling). Samples were fractionated into four size fractions (<200, 200-500, 500-1000, and >1000 ?m). The only factor that significantly affected copepod biomass was chlorophyll concentration, which explained 71% of the variation. The gut fluorescence technique was used to estimate ingestion rates and experiments were performed to obtain naupliar gut evacuation rates. We found a similar relationship between nauplii gut evacuation rates and temperature as that described by Dam and Peterson [1988. The effect of temperature on the gut clearance rate constant of planktonic copepods. Journal of Experimental Marine Biology and Ecology 123, 1-14] for larger copepods. Chlorophyll ingested daily by copepods was higher in regions affected by Mauritanian and Equatorial upwellings and the South Subtropical Convergence. Copepods were found to be major grazers of phytoplankton. Grazing impact upon primary production was more important for upwelling areas, with values higher than 100% of primary production at some stations. Even in oligotrophic gyres, where the relative importance of protists increases, copepods exert substantial feeding impact on their autotrophic prey. In oligotrophic gyres, small copepods and nauplii were relatively more abundant, and accounted for a higher amount of total chlorophyll ingestion than larger ones. Thus, studies with 200 ?m mesh nets in oligotrophic areas are seriously underestimating nauplii and copepod abundance and grazing impact on phytoplankton.

  17. Transport and retention of dormant copepods in the Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Johnson, Catherine; Pringle, James; Chen, Changsheng

    2006-11-01

    Variability in the availability of dormant copepods to seed productive shelf areas has been hypothesized to influence the abundance of the dominant copepod species Calanus finmarchicus in several regions of the North Atlantic. One source of this variability is advection of dormant copepods in deep water. Using Lagrangian particle simulations, we examined the influence of environmental forcing and copepod behavior on transport and retention of dormant C. finmarchicus in the deep Gulf of Maine, in the northwestern Atlantic. Retention in the Gulf of Maine was relatively high, >40% over 6 months, under all conditions simulated. Transport within the Gulf of Maine was high, resulting in shifts of eastern copepods into the western Gulf and of upstream copepods, from slope and Scotian Shelf waters, into the eastern Gulf. Copepod behavior during dormancy was a major source of uncertainty, but it is probably not a major source of interannual variability in retention. Retention increased with the initial depth of dormant copepods, and vertical positioning behavior had a strong influence on retention for simulations started at depths greater than 150 m, because copepods that can stay below basin sill depths are retained. Mean cross-shore winds reduced retention slightly (<2% absolute difference), and mean alongshore winds increased retention by 4-8%. Wind-driven interannual variability in retention was low. Variability in Scotian Shelf inflow had a greater influence on retention than did variability in winds, and inflow-driven changes in retention may contribute to interannual variability in copepod abundance associated with changes in deep-water temperature. However, estimates of advective loss are relatively low compared to measured reductions in dormant copepod abundance, and mortality is probably a major factor in this reduction.

  18. Analysis of the parasitic copepod species richness among Mediterranean fish

    NASA Astrophysics Data System (ADS)

    Raibaut, Andr; Combes, Claude; Benoit, Franoise

    1998-06-01

    The Mediterranean ichthyofauna is composed of 652 species belonging to 405 genera and 117 families. Among these, 182 were studied for their parasitic copepods. The analysis of all the works conducted on these crustacea yielded 226 species distributed in 88 genera and 20 families. For each fish species we have established a file providing the species name of the fish, its family, its geographical distribution within the Mediterranean and some of its bio-ecological characteristics. Within each file, all the parasitic copepod species reported on each host species were listed. This allowed to know the species richness (SR) of these hosts. We thus produced 182 files within which 226 copepod species are distributed. A program was created under the Hypercard software, in order to analyse our data. Two parameters were studied. The first one is the mean species richness (MSR), which corresponds to the mean of the different SR found on the different host species. The second is the parasite-host ratio (P/H), which is the ratio of the number of copepod species by the number of host species. These parameters are calculated by our program for all the 182 species of Mediterranean fishes retained in our investigation, on the first hand, and, on the second hand, for one particular group of fish species. We used the following variables to investigate their correlations with copepod species richness: taxonomyfish families, genera and species; biometrymaximal size of the adult fish; eco-ethologymode of life (benthic, pelagic or nectonic), displacements (sedentary, migratory with environmental change, or migratory without environmental change), behaviour (solitary or gregarious). Other variables (colour, food, reproduction, abundance, distribution area) were also analysed but did not reveal any clear correlation. Providing that our study does not rely on quantitative (prevalence, intensity) but qualitative basis our aim was only to reveal some tendencies. These tendencies are as follows: (1) In many cases, parasite and host phylogeny seem to play an important role. There are fish families with copepods and families with few species of these parasites. The phyletic constraints could be due to the morphological characteristics of the habitat (e.g. structure of the gills) or biological/ecological characteristics that we were unable to identify. (2) It appears that the presence in a same environment of related fish species (e.g. several species of the same genus, or numerous genera of the same family) is correlated with high parasite richness. A likely explanation is that such situations favours alternated processes of lateral transfers and speciation. (3) Some eco-ethological criteria seem to favour the establishment of a large parasite species richness. It should be noted for instance that Mediterranean fishes the most often infected with copepods are generally nectonic or pelagic, migratory, and gregarious species.

  19. 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...

  20. A new notodelphyid copepod, Doropygopsis arctica sp. nov. (Cyclopoida), parasitic in ascidian of the Molgula arctica from the White Sea

    NASA Astrophysics Data System (ADS)

    Marchenkov, A. V.

    1998-06-01

    Doropygopsis arctica, a new species of notodelphyid cyclopoid from the branchial cavity of Molgula arctica Kiaer, 1896 (Ascidiacea) in Chupa Bay (Kandalakshskiy Zaliv, White Sea) is described. The new species differs from the two other congeners by the fine structure of some cephalosomic appendages and swimming legs. The diagnosis for Doropygopsis is redefined.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    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.

  2. Checklist of copepods (Crustacea: Calanoida, Cyclopoida,Harpacticoida) from Wyoming, USA, with new state records

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Presentation of a comprehensive checklist of the copepod fauna of Wyoming, USA with 41 species of copepods; based on museum specimens, literature reviews, and active surveillance. Of these species 19 were previously unknown from the state. This checklist includes species in the families Centropagida...

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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.

  4. Microbial diversity associated with copepods in the North Atlantic subtropical gyre.

    PubMed

    Shoemaker, Katyanne M; Moisander, Pia H

    2015-07-01

    Patchiness of marine microbial communities has an important influence on microbial activities in the ocean, particularly in the oligotrophic open ocean where bioavailable nutrients are otherwise scarce. Such spatial heterogeneity is present in associations with dead and living particles, including zooplankton. The microbial community composition of mesozooplankton was investigated from the Sargasso Sea using 16S rRNA amplicon pyrosequencing. Zooplankton microbiomes were studied on the copepods Undinula vulgaris, Pleuromamma spp., Sapphirina metalina, Pseudocalanus spp. and Tigriopus sp., and an amphipod, Phrosina semilunata. The overall richness was lower in the zooplankton than in the seawater, and zooplankton-specific bacterial communities were distinct from the communities in seawater. Gammaproteobacteria dominated in all zooplankton studied, with Vibrio spp. highly represented. Firmicutes were detected in all copepods, providing evidence for anaerobic conditions present on the copepods. Bacterial groups known to grow on concentrated organic substrates or to prevent biofouling were highly represented in association with copepods, suggesting they benefit from copepod-derived nutrients or carbon. The described copepod microbiome has similarities to communities previously described in coastal copepods, suggesting some aspects of the copepod microbiome are not habitat specific. The communities are distinct of that in seawater, demonstrating significant microbial patchiness in association with marine zooplankton in the oligotrophic open ocean. PMID:26077986

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2005-02-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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.

  9. Macroevolutionary patterns of sexual size dimorphism in copepods.

    PubMed

    Hirst, Andrew G; Kirboe, Thomas

    2014-09-22

    Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes. PMID:25100692

  10. Macroevolutionary patterns of sexual size dimorphism in copepods

    PubMed Central

    Hirst, Andrew G.; Kirboe, Thomas

    2014-01-01

    Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes. PMID:25100692

  11. The feeding ecology of the copepod Centropages typicus (Kryer)

    NASA Astrophysics Data System (ADS)

    Calbet, Albert; Carlotti, Franois; Gaudy, Raymond

    2007-02-01

    Here we report on the current knowledge on the feeding ecology of the planktonic copepod Centropages typicus. We describe the foraging process of C. typicus from the detection of prey to their digestion, considering also the effects of several physical variables on the feeding activity of the species. C. typicus is an omnivorous copepod that feeds on a wide spectrum of prey, from small algae (3-4 ?m equivalent spherical diameter, ESD) to yolk-sac fish larvae (3.2-3.6 mm length). It uses both suspensivorous and ambush feeding strategies, depending on the characteristics of the prey. In general, C. typicus exhibits selection for large motile prey, such as ciliates or dinoflagellates, both in nature and laboratory, and this selective pattern is enhanced under moderate intensities of turbulence. Daily rations in the field are somewhat lower than those found in the laboratory, which indicates food limitation. This fact, together with the relatively modest capacity of the species to adapt to fluctuations in food availability may explain the geographical distribution of C. typicus, being restricted to near-shelf waters. In general, it does not seem that C. typicus feeding severely impacts planktonic populations. However, the occasional importance of the species in certain ecosystems is also apparent.

  12. Mechanoreceptors in calanoid copepods: designed for high sensitivity.

    PubMed

    Weatherby, T M; Lenz, P H

    2000-01-01

    The mechanoreceptors of the first antennae of Pleuromamma xiphias, a mesopelagic calanoid copepod, are critical for the detection of potential threats. These receptors exceed the physiological performance of other crustacean mechanoreceptors in sensitivity to water velocities as well as in frequency response. A study of these receptors was initiated to elucidate structure-function relationships. Morphologically, the receptors resemble the arthropod scolopidial organs by the presence of a scolopale tube. However, the rigidity of the copepod receptors greatly exceeds those described for crustaceans and other arthropods. The scolopale tube completely encloses the distal dendrites and it is firmly anchored to the cuticle. Microtubules are organized in register and arise from microtubule subfibers associated with crescent-shaped rods which extend from the basal body region to the setal socket. The distal dendrites are filled with a large number of cross-linked microtubules. Termination of the distal dendrites inside the lumen of the setae is gradual with a firm anchoring to the cuticle. A likely mechanism for mechanotransduction would involve a linkage between individual microtubules and mechano-gated channels in the dendritic membrane. The rigidity probably contributes to the high frequency sensitivity, and termination of the dendrite inside the seta increases the overall sensitivity of these receptors. PMID:18088933

  13. Marine copepod diversity patterns and the metabolic theory of ecology.

    PubMed

    Rombouts, Isabelle; Beaugrand, Grgory; Iba?ez, Frdric; Chiba, Sanae; Legendre, Louis

    2011-06-01

    Temperature is a powerful correlate of large-scale terrestrial and marine diversity patterns but the mechanistic links remain unclear. Whilst many explanations have been proposed, quantitative predictions that allow them to be tested statistically are often lacking. As an important exception, the metabolic theory of ecology (MTE) provides a rather robust technique using the relationship between diversity, temperature and metabolic rate in order to elucidate the ultimate underlying mechanisms driving large-scale diversity patterns. We tested if the MTE could explain geographic variations in marine copepod diversity on both ocean-wide and regional scales (East Japan Sea and North East Atlantic). The values of the regression slopes of diversity (ln taxonomic richness) over temperature (1/kT) across all spatial scales were lower than the range predicted by the metabolic scaling law for species richness (i.e. -0.60 to -0.70).We therefore conclude that the MTE in its present form is not suitable for predicting marine copepod diversity patterns. These results further question the applicability of the MTE for explaining diversity patterns and, despite the relative lack of comparable studies in the marine environment, the generality of the MTE across systems. PMID:21153740

  14. Assimilation and regeneration of trace elements by marine copepods

    USGS Publications Warehouse

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

    1996-01-01

    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.

  15. Do copepods inhabit hypersaline waters worldwide? A short review and discussion

    NASA Astrophysics Data System (ADS)

    Anufriieva, Elena V.

    2015-11-01

    A small number of copepod species have adapted to an existence in the extreme habitat of hypersaline water. 13 copepod species have been recorded in the hypersaline waters of Crimea (the largest peninsula in the Black Sea with over 50 hypersaline lakes). Summarizing our own and literature data, the author concludes that the Crimean extreme environment is not an exception: copepod species dwell in hypersaline waters worldwide. There are at least 26 copepod species around the world living at salinity above 100; among them 12 species are found at salinity higher than 200. In the Crimea Cletocamptus retrogressus is found at salinity 36010-3 (with a density of 1 320 individuals/m3) and Arctodiaptomus salinus at salinity 30010-3 (with a density of 343 individuals/m3). Those species are probably the most halotolerant copepod species in the world. High halotolerance of osmoconforming copepods may be explained by exoosmolyte consumption, mainly with food. High tolerance to many factors in adults, availability of resting stages, and an opportunity of long-distance transportation of resting stages by birds and/or winds are responsible for the wide geographic distribution of these halophilic copepods.

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

    USGS Publications Warehouse

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

    2003-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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.

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

    PubMed Central

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

    2012-01-01

    The timing and magnitude of an escape reaction is often the determining factor governing a copepods 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

  19. Feeding impacts of ontogenetically migrating copepods on the spring phytoplankton bloom in the Oyashio region

    NASA Astrophysics Data System (ADS)

    Kobari, T.; Inoue, Y.; Nakamura, Y.; Okamura, H.; Ota, T.; Nishibe, Y.; Ichinomiya, M.

    2010-09-01

    We investigated the feeding habits and grazing rates of the ontogenetically migrating copepods in the Oyashio region to evaluate their grazing impacts on the food web during the spring phytoplankton bloom. The bloom was in progress from early to late April, although chlorophyll a concentrations fluctuated considerably with the frequent exchange of different water masses. Biomass of the copepod community reached a maximum in mid-April when late copepodites of Neocalanus cristatus, Neocalanus flemingeri and Eucalanus bungii contributed to the biomass increase. Gut pigment contents of the predominant copepods were much higher during the bloom compared with the levels in March (pre-bloom). The temporal fluctuations were not correlated with those of mean chlorophyll a concentrations in the 0-50 m layer. Feeding experiments indicated that major food items for the copepods were centric diatoms and flagellates. During the period of lower ambient chlorophyll, the copepods changed their heterotrophic prey from naked ciliates to tintinnids. Apparent clearance rates were positive for naked ciliates and negative for heterotrophic nanoplankton, Cryptophyceae and bacteria when chlorophyll was high, suggesting trophic cascade effects from copepod feeding even during the phytoplankton bloom. The carbon demands of the copepod community were estimated to be 156 mgC m -2 day -1 in early March to 797 mgC m -2 day -1 in mid-April. The grazing rates on phytoplankton reached 480 mgC m -2 day -1, equivalent to as much as 28% of primary production. Non-phytoplankton prey supported 40 to 71% of the copepod carbon requirement. These results suggest that the copepod community does not graze the phytoplankton bloom down, but it does have significant impacts on microbial food webs.

  20. Seasonality of the copepod assemblages associated with interplay waters off northeastern Taiwan

    NASA Astrophysics Data System (ADS)

    Tseng, Li-Chun; Hung, Jia-Jang; Chen, Qing-Chao; Hwang, Jiang-Shiou

    2013-09-01

    This study investigated copepod assemblages in the regime around Turtle Island off northern Taiwan to trace South China Sea water (SCSW) flowing northward with the Kuroshio Current. Seasonal variations of copepod assemblages demonstrated a dynamic succession of changes in copepod populations; the average abundance for total copepods ranged from 102.58 ± 53.38 in December to 1669.89 ± 1866.17 in March (individuals m-3). A total of 87 copepod species representing 36 genera and 21 families were identified. Among all samples, Temora turbinata dominated the copepods by a relative abundance (RA) of 26.89 %, followed by Paracalanus parvus (RA: 22.34 %) and Corycaeus ( Ditrichocorycaeus) affinis (RA: 12.77 %). Only the Acrocalanus gracilis species was recorded in all samples. Results of one-way ANOVA revealed that the number of copepod species, indices of richness, evenness, and Shannon-Wiener diversity differed significantly in five different cruises. The density of five copepod species ( Gaetanus minor, Calanus sinicus, Eucalanus elongates, Rhincalanus nasutus, and Rhincalanus rostrifrons) exhibited a significant negative correlation with seawater temperature. In contrast, the density of Canthocalanus pauper and Undinula vulgaris was significantly positively correlated with seawater temperature. The cold-water indicator species, C. sinicus, recorded in samples of March and May indicated the effect of China Coast Water (CCW) on copepod communities in the study area. Furthermore, the presence of Calanoides philippinensis in May samples strongly indicated that the SCSW may reach the Turtle Island area. Consequently, C. philippinensis and C. sinicus can be used to trace SCSW and CCW, respectively, in the study area.

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

    PubMed

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

    2010-01-01

    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

  2. Effects of dispersant and oil on survival and swimming activity in a marine copepod.

    PubMed

    Cohen, Jonathan H; McCormick, Lillian R; Burkhardt, Stephanie M

    2014-04-01

    Knowledge of lethal and sublethal effects of crude oil and dispersants on mesozooplankton are important to understanding ecosystem impacts of oil spills in marine environments. Here we (1) establish median lethal concentrations for water accommodated fractions of Corexit EC9500A dispersant, MC-252 crude oil (WAF), and dispersed crude oil (CEWAF) for the coastal copepod Labidocera aestiva, and (2) assess acute effects on L. aestiva swimming activity. Mortality assays with L. aestiva support that copepods are more sensitive than other zooplankton taxa to dispersant toxicity, while WAF and CEWAF are generally similar in their toxicity to this copepod species and other zooplankton. Acute effects on L. aestiva activity included impaired swimming upon WAF and CEWAF exposure. These results highlight that copepods are particularly sensitive to dispersant exposure, with acute effects on survival most evident with dispersant alone, and on swimming behavior when dispersant is mixed with crude oil. PMID:24402000

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

    PubMed

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

    2014-06-01

    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

  4. Copepod Aggregations: Influences of Physics and Collective Behavior

    NASA Astrophysics Data System (ADS)

    Flierl, Glenn R.; Woods, Nicholas W.

    2015-02-01

    Dense copepod aggregations form in Massachusetts Bay and provide an important resource for right whales. We re-examine the processes which might account for the high concentrations, investigating both horizontally convergent flow, which can increase the density of depth-keeping organisms, and social behavior. We argue that the two act in concert: social behavior creates small dense patches (on the scale of a few sensing radii); physical stirring brings them together so that they merge into aggregations with larger scales; it also moves them into areas of physical convergence which retain the increasingly large patch. But the turbulence can also break this apart, suggesting that the overall high density in the convergence zone will not be uniform but will instead be composed of multiple transient patches (which are still much larger than the sensing scale).

  5. Parasitic copepods from Egyptian Red Sea fishes: Bomolochidae Claus, 1875.

    PubMed

    El-Rashidy, Hoda Hassan; Boxshall, Geoffrey Allan

    2016-02-01

    Two species of parasitic copepods from the genus Bomolochus von Nordmann, 1832 (Cyclopoida: Bomolochidae) are redescribed in detail, based on material collected from the gills of Red Sea fishes. Host material was caught at El-tor, near Sharm El-Sheikh, and in the Gulf of Suez, Egypt. Both sexes of Bomolochus bellones Burmeister, 1835 were collected from the gills of a needlefish Tylosurus choram (Rppell) caught in the Gulf of Suez. This is a new host record. The female is well characterised so only the male is described. Adult females of Bomolochus minus Lin & Ho, 2005 were obtained from the branchial cavities and gills of mojarra Gerres oyena (Forsskl). This species was known only from its original description in Taiwan, and this report constitutes a new host record and a significant range extension. Both parasite species are new records for Egyptian Red Sea waters. PMID:26790683

  6. Comparison of marine copepod outfluxes: nature, rate, fate and role in the carbon and nitrogen cycles.

    PubMed

    Frangoulis, C; Christou, E D; Hecq, J H

    2005-01-01

    We compare the nature of copepod outfluxes of nonliving matter, the factors controlling their rate and their fate, and finally their role, particularly their relative importance in the carbon and nitrogen cycle. Copepods release dissolved matter through excretion and respiration and particulate matter through production of faecal pellets, carcasses, moults, and dead eggs. Excretion liberates several organic C, N, and P compounds and inorganic N and P compounds, with inorganic compounds constituting the larger part. The faecal pellets of copepods are covered by a peritrophic membrane and have a highly variable size and content. There is less information on the nature of other copepod particulate products. The weight-specific rates of posthatch mortality, respiration, excretion, and faecal pellet production have similar C or N levels and are higher than those of moulting and egg mortality. In general, most important factors controlling these rates are temperature, body mass, food concentration, food quality, and faunistic composition. Physical and biological factors govern the vertical fate of copepod products by affecting their sedimentation speed and concentration gradient. The physical factors are sinking speed, advection, stratification, turbulent diffusion, and molecular diffusion. They influence the sedimentation speed and degradation of the copepod products. The biological factors are production, biodegradation (by zooplankton, nekton, and microorganisms) and vertical migration of copepods (diel or seasonal). Physical degradation and biodegradation by zooplankton and nekton are faster than biodegradation by microorganisms. The most important copepod outfluxes are excretion and faecal pellet production. Excretion offers inorganic nutrients that can be directly used by primary producers. Faecal pellets have a more important role in the vertical transport of elements than the other particulate products. Most investigation has focused on carbon burial in the form of copepod faecal pellets, measured by sediment traps, and on the role of ammonia excretion in nutrient recycling. Full evaluation of the role of copepod products in the transport and recycling of elements and compounds requires a quantification of all copepod products and their different fates, particularly detritiphagy, remineralization, and integration as marine snow. PMID:15596169

  7. Cryptic ecological diversification of a planktonic estuarine copepod, Acartia tonsa.

    PubMed

    Chen, Gang; Hare, Matthew P

    2008-03-01

    The recent discovery of cryptic species in marine holoplankton, organisms that 'drift' in oceanic currents throughout their life cycle, contrasts with their potential for long-distance passive dispersal and presumably high gene flow. These observations suggest that holoplankton species are adapting to surprisingly small-scale oceanographic features and imply either limited dispersal or strong selection gradients. Acartia tonsa is a widespread and numerically dominant estuarine copepod containing deep mitochondrial lineages within and among populations along the northwestern Atlantic coast. In this study, we intensively investigated A. tonsa populations in Chesapeake Bay with the goals of testing species status for the deep lineages and testing for their association with environmental features over space and time. Phylogenetic analyses of DNA sequences from mitochondrial cytochrome c oxidase I (mtCOI) and the nuclear ribosomal internal transcribed spacer (nITS) resolved two concordant monophyletic clades. Deep divergence between the two clades (13.7% uncorrected sequence divergence for mtCOI and 32.2% for nITS) and genealogical concordance within sympatric populations strongly suggest that the two clades represent reproductively isolated cryptic species. Based on restriction fragment length polymorphisms of mtCOI, representatives from the two clades were found consistently associated with contrasting salinity regimes (oligohaline vs. meso-polyhaline) with an overlap between 2 and 12 PSU in samples from 1995 to 2005. Finding these patterns in one of the best-known estuarine copepods reinforces the conclusion that marine biodiversity is underestimated, not only in terms of species numbers, but also with respect to niche partitioning and the potential importance of ecological divergence in marine holoplankton. PMID:18248575

  8. Effects of Harpacticus sp. (Harpacticoida, copepod) grazing on dimethylsulfoniopropionate and dimethylsulfide concentrations in seawater

    NASA Astrophysics Data System (ADS)

    Yu, Juan; Tian, Ji-Yuan; Yang, Gui-Peng

    2015-05-01

    We conducted 9 d and 24 h ingestion experiments to investigate the effects of copepod grazing on the concentrations of dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) in seawater. Data from the 9 d trial showed that copepod Harpacticus sp. (Harpacticoida, copepod) grazing increased DMS (0-20%) and dissolved DMSP (DMSPd) (0-128%) apparently, accompanied by a significant reduction of particulate DMSP (DMSPp) in algal culture (0-30%). Ingestion rates (IRs) and pellet production rates (PPRs) of Harpacticus sp. varied with diet species (Platymonas subcordiformis (PS), Nitzschia closterium (NC), Skeletonema costatum (SC), Isochrysis galbana (IG), Prymnesium parvum (PP) or Heterosigma akashiwo (HA)), algal concentration, salinity and temperature. Harpacticus sp. fed on PP showed the lowest IRs (female/male, 0.72/0.53 104cells copepod- 1 h- 1) and PPRs (female/male, 0.75/0.5 pellets copepod- 1 h- 1), accompanied with the largest amounts of DMS and DMSPd,p (sum of DMSPd and DMSPp). IRs, PPRs, DMS and DMSPf (DMSP in fecal pellet) increased with the increase of food concentration and peaked at 25 104 cells mL- 1I. galbana. High salinity decreased IRs, PPRs, DMS and DMSPf and increased DMSPz (DMSP in copepod body) and DMSPd,p. IRs, PPRs, DMS and DMSPf increased with the increase of temperature from 15 to 25 C, whereas DMSPz and DMSPd,p contents decreased. Pearson correlation analysis results showed that DMS concentrations presented positive relationships with IRs in algal concentration, salinity and temperature experiments (r = 0.746; P < 0.01). The contribution of DMSPz, DMSPf, DMS and DMSPd,p concentration to the total amounts (DMSPz + DMSPf + DMS + DMSPd,p) was 4-37%, 3-36%, 8-42% and 9-89%, respectively, indicating that DMSP was transferred to copepod tissue and fecal pellet via grazing. Our results are helpful for further understanding of the role of copepod grazing on DMS biogeochemical cycle.

  9. Mandibular gnathobases of marine planktonic copepods feeding tools with complex micro- and nanoscale composite architectures

    PubMed Central

    Gorb, Stanislav N

    2015-01-01

    Summary Copepods are dominant members of the marine zooplankton. Their diets often comprise large proportions of diatom taxa whose silicified frustules are mechanically stable and offer protection against grazers. Despite of this protection, many copepod species are able to efficiently break even the most stable frustule types. This ability requires specific feeding tools with mechanically adapted architectures, compositions and properties. When ingesting food, the copepods use the gnathobases of their mandibles to grab and, if necessary, crush and mince the food items. The morphology of these gnathobases is related to the diets of the copepods. Gnathobases of copepod species that mainly feed on phytoplankton feature compact and stable tooth-like structures, so-called teeth. In several copepod species these gnathobase teeth have been found to contain silica. Recent studies revealed that the siliceous teeth are complex microscale composites with silica-containing cap-like structures located on chitinous exoskeleton sockets that are connected with rubber-like bearings formed by structures with high proportions of the soft and elastic protein resilin. In addition, the silica-containing cap-like structures exhibit a nanoscale composite architecture. They contain some amorphous silica and large proportions of the crystalline silica type ?-cristobalite and are pervaded by a fine chitinous fibre network that very likely serves as a scaffold during the silicification process. All these intricate composite structures are assumed to be the result of a coevolution between the copepod gnathobases and diatom frustules in an evolutionary arms race. The composites very likely increase both the performance of the siliceous teeth and their resistance to mechanical damage, and it is conceivable that their development has favoured the copepods dominance of the marine zooplankton observed today. PMID:25821707

  10. Distribution, diversity and density of wolbachial infections in cladocerans and copepods from Thailand.

    PubMed

    Wiwatanaratanabutr, Itsanun

    2013-11-01

    Species of the genus Wolbachia comprise a group of Rickettsia-like, maternally-inherited bacteria that cause several reproductive alterations in arthropod hosts. The best known are cytoplasmic incompatibility and feminization. Here, the first systematic surveys of wolbachial infections in cladocerans and copepods from six geographic regions of Thailand, including Northern, Northeastern, Western, Central, Eastern and Southern are reported. Using gene amplification assays with wsp and groE primers, wolbachiae were detected in 239 (4 spp.) of 1885 (57 spp.) copepods and cladocerans from all regions of Thailand surveyed. Screening results obtained with wsp primers or groE primers were similar in all cases. The presence of wolbachiae was only detected in copepods, not in cladocerans. Sex ratio analyses of the progeny of two species of copepods, Mesocyclops aspericornis and Mesocyclops thermocyclopoides, naturally or artificially infected with wolbachiae showed infection causes feminization (female-bias). The relative density if infection in naturally infected populations of three copepod species, M. thermocyclopoides, Heliodiaptomus elegans and Neodiaptomus blachei, were determined using real-time quantitative PCR assay based on the wsp gene. The density of wolbachiae in M. thermocyclopoides was significantly higher than in the other two species. These results suggest that wolbachial infections are distributed throughout Thailand, and that possibly the natural occurrence of these in copepods may be due to their predation on mosquito larvae. This apparent novel biology may have importance as a genetic drive system for control of vector borne diseases in the future. PMID:24080157

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

    PubMed Central

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

    2012-01-01

    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

  12. Do inactivated microbial preparations improve life history traits of the copepod Acartia tonsa?

    PubMed

    Drillet, Guillaume; Rabarimanantsoa, Tahina; Froul, Stphane; Lamson, Jacob S; Christensen, Anette M; Kim-Tiam, Sandra; Hansen, Benni W

    2011-10-01

    We have tested a microbial preparation with probiotic effects (PSI; Sorbial A/S DANISCO) on the calanoid copepod Acartia tonsa (Dana) development time and reproduction effectiveness in culture. The hypotheses were that PSI increases the productivity and quality of copepods in culture (increased egg production and hatching success, HS). This was carried out because the use of copepods as live prey in aquaculture could increase the number of fish successfully raised through their entire life cycle. However, the availability of copepods is limited by their difficulty to be effectively raised. Our results show that the addition of PSI to the algal food increased the individual size of the adult females and their egg production. The PSI, together with Rhodomonas salina, also increased the HS of the eggs produced by PSI-treated females. These effects were observed despite that the biochemical analysis of the PSI revealed that it is a nutritionally poor food lacking essential fatty acids, and hence it cannot be used alone to raise copepods but instead as a food additive. This is the first demonstration that the effectiveness of copepod culturing can be improved using microbial preparations as a food additive. PMID:21213117

  13. Lipid nanocapsules as a new delivery system in copepods: Toxicity studies and optical imaging.

    PubMed

    Stancheva, Stefka; Souissi, Anissa; Ibrahim, Ali; Barras, Alexandre; Spriet, Corentin; Souissi, Sami; Boukherroub, Rabah

    2015-11-01

    In this paper, we investigated the potential of lipid nanocapsules (LNCs) as a delivery system of small hydrophobic molecules, polycyclic aromatic hydrocarbons (PAHs) - pyrene, fluoranthene, phenanthrene, in the copepod Acartia tonsa. The LNCs were produced by a phase inversion process with a nominal size of 50nm. These nanocapsules were obtained without organic solvent and with pharmaceutically acceptable excipients. The PAHs-LNCs displayed a stable monodisperse size distribution and a good stability in sea water for 7 days. By using fluorescent LNCs, it was possible to evidence LNCs ingestion by the copepods using confocal laser scanning microscopy. While blank LNCs are not toxic to copepods at tested concentrations, PAH-loaded LNCs were found to be very toxic on A. tonsa with a high mortality rate reaching 95% after 72h exposure to 200nM pyrene-loaded LNCs. On the other hand, when acetone is used to dissolve an equivalent concentration of PAHs in sea water, the copepod mortality is 10 times lower than using LNCs as nano-delivery system. This confirms the efficiency of using LNCs to deliver molecules directly in the gut or copepod carapace. The small size and non toxicity of these delivery nano-systems make them suitable for drug delivery to copepods. PMID:26280818

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

    PubMed

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

    2012-01-01

    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

  15. Light primes the escape response of the calanoid copepod, Calanus finmarchicus.

    PubMed

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

    2012-01-01

    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

  16. High-quality RNA extraction from copepods for Next Generation Sequencing: A comparative study.

    PubMed

    Asai, Sneha; Ianora, Adrianna; Lauritano, Chiara; Lindeque, Penelope K; Carotenuto, Ylenia

    2015-12-01

    Despite the ecological importance of copepods, few Next Generation Sequencing studies (NGS) have been performed on small crustaceans, and a standard method for RNA extraction is lacking. In this study, we compared three commonly-used methods: TRIzol, Aurum Total RNA Mini Kit and Qiagen RNeasy Micro Kit, in combination with preservation reagents TRIzol or RNAlater, to obtain high-quality and quantity of RNA from copepods for NGS. Total RNA was extracted from the copepods Calanus helgolandicus, Centropages typicus and Temora stylifera and its quantity and quality were evaluated using NanoDrop, agarose gel electrophoresis and Agilent Bioanalyzer. Our results demonstrate that preservation of copepods in RNAlater and extraction with Qiagen RNeasy Micro Kit were the optimal isolation method for high-quality and quantity of RNA for NGS studies of C. helgolandicus. Intriguingly, C. helgolandicus 28S rRNA is formed by two subunits that separate after heat-denaturation and migrate along with 18S rRNA. This unique property of protostome RNA has never been reported in copepods. Overall, our comparative study on RNA extraction protocols will help increase gene expression studies on copepods using high-throughput applications, such as RNA-Seq and microarrays. PMID:25546577

  17. Sensory-Motor Systems of Copepods involved in their Escape from Suction Feeding.

    PubMed

    Yen, Jeannette; Murphy, David W; Fan, Lin; Webster, Donald R

    2015-07-01

    Copepods escape well by detecting minute gradients in the flow field; they react quickly, and swim away strongly. As a key link in the aquatic food web, these small planktonic organisms often encounter suction-feeding fish. Studies have identified certain hydrodynamic features that are created by the approach of this visual predator and the generation of its suction flow for capturing food. Similarly, studies have identified certain hydrodynamic features that evoke the evasive response of copepods. This is a review of the copepod sensory motor system as pertains to understanding their response to suction-feeding fish. Analyses of the reaction time, threshold sensitivity, structure of sensors, and evasive behavior by this key prey of fish can be useful for evaluating the effectiveness of feeding tactics in response to suction flow. To illustrate, we present results comparing a copepod from a fishless lake (Hesperodiaptomus shoshone) to a copepod from a rich fishing ground (Calanus finmarchicus). We designed a flow mimic that produces a realistic mushroom-cap-shaped flow field and realistic accelerations of flow; the copepods treated the mimic as a threat and performed jumps directed up and away from the siphon. Calanus finmarchicus responded at an average threshold strain rate of 18.7/s, escaped at 0.46 m/s, and traveled 5.99 mm, most frequently as a single jump. Hesperodiaptomus shoshone responded at a strain rate of 15.1/s that is not significantly different, escaped more slowly at 0.22 m/s and traveled a shorter distance of 3.01 mm using a series of hops. The high variability noted in the initial angle of the body and the maximum change in body angle suggests that unpredictability in the escape maneuver is another aspect of the tactic of copepods. The speed of the escape by small copepods 2-3 mm long is overwhelmed by the speed of the attack by the much larger, faster fish; if the copepod reacts when it is within the fish's arena of capture (<1.5 mm from mouth), it will be eaten. The copepod, however, has an acutely sensitive array of mechanosensors that perceive the flow field of the fish at distances of 3-6 mm, or outside the fish's range of capture. The copepod also has a rapid and strong locomotory response, thereby increasing the odds that the copepod will survive-but speed is unlikely to be the best tactic for staying alive. Instead, the copepod accelerates from 61.3 to 96.5 m/s(2) or more than 20 times stronger than the lunge of a fish. This collection of capabilities of copepods enables them to remain one of the most abundant multicellular organisms on our planet. PMID:26015485

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

    PubMed Central

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

    2014-01-01

    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

  19. Bloom-forming cyanobacteria support copepod reproduction and development in the Baltic Sea.

    PubMed

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

    2014-01-01

    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

  20. Characterization and analysis of ribosomal proteins in two marine calanoid copepods

    NASA Astrophysics Data System (ADS)

    Yang, Feifei; Xu, Donghui; Zhuang, Yunyun; Huang, Yousong; Yi, Xiaoyan; Chen, Hongju; Liu, Guangxing; Zhang, Huan

    2016-02-01

    Copepods are among the most abundant and successful metazoans in the marine ecosystem. However, genomic resources related to fundamental cellular processes are still limited in this particular group of crustaceans. Ribosomal proteins are the building blocks of ribosomes, the primary site for protein synthesis. In this study, we characterized and analyzed the cDNAs of cytoplasmic ribosomal proteins (cRPs) of two calanoid copepods, Pseudodiaptomus poplesia and Acartia pacifica. We obtained 79 cRP cDNAs from P. poplesia and 67 from A. pacifica by cDNA library construction/sequencing and rapid amplification of cDNA ends. Analysis of the nucleic acid composition showed that the copepod cRP-encoding genes had higher GC content in the protein-coding regions (CDSs) than in the untranslated regions (UTRs), and single nucleotide repeats (>3 repeats) were common, with "A" repeats being the most frequent, especially in the CDSs. The 3'-UTRs of the cRP genes were significantly longer than the 5'-UTRs. Codon usage analysis showed that the third positions of the codons were dominated by C or G. The deduced amino acid sequences of the cRPs contained high proportions of positively charged residues and had high pI values. This is the first report of a complete set of cRP-encoding genes from copepods. Our results shed light on the characteristics of cRPs in copepods, and provide fundamental data for further studies of protein synthesis in copepods. The copepod cRP information revealed in this study indicates that additional comparisons and analysis should be performed on different taxonomic categories such as orders and families.

  1. 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...

  2. 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...

  3. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

    NASA Astrophysics Data System (ADS)

    Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

    2015-11-01

    The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

  4. Temporal Stability of Genetic Structure in a Mesopelagic Copepod

    PubMed Central

    Goetze, Erica; Andrews, Kimberly R.; Peijnenburg, Katja T. C. A.; Portner, Elan; Norton, Emily L.

    2015-01-01

    Although stochasticity in oceanographic conditions is known to be an important driver of temporal genetic change in many marine species, little is known about whether genetically distinct plankton populations can persist in open ocean habitats. A prior study demonstrated significant population genetic structure among oceanic gyres in the mesopelagic copepod Haloptilus longicornis in both the Atlantic and Pacific Oceans, and we hypothesized that populations within each gyre represent distinct gene pools that persist over time. We tested this expectation through basin-scale sampling across the Atlantic Ocean in 2010 and 2012. Using both mitochondrial (mtCOII) and microsatellite markers (7 loci), we show that the genetic composition of populations was stable across two years in both the northern and southern subtropical gyres. Genetic variation in this species was partitioned among ocean gyres (FCT = 0.285, P < 0.0001 for mtCOII, FCT = 0.013, P < 0.0001 for microsatellites), suggesting strong spatial population structure, but no significant partitioning was found among sampling years. This temporal persistence of population structure across a large geographic scale was coupled with chaotic genetic patchiness at smaller spatial scales, but the magnitude of genetic differentiation was an order of magnitude lower at these smaller scales. Our results demonstrate that genetically distinct plankton populations persist over time in highly-dispersive open ocean habitats, and this is the first study to rigorously test for temporal stability of large scale population structure in the plankton. PMID:26302332

  5. Trampling on coral reefs: tourism effects on harpacticoid copepods

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    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.

  6. Wax ester composition influences the diapause patterns in the copepod Calanoides acutus

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

    Many calanoid copepods inhabiting high latitude environments overwinter at depth in the water column in a state of diapause and the large wax ester reserves that they contain are central to this process. Here we compare the abundance, depth distribution, lipid content and wax ester composition of individual CV Calanoides acutus collected from the Southern Ocean at depth horizons ranging from the surface to 1000 m. Abundances of CV C. acutus varied considerably between locations, ranging from 44 to 1256 m -2. Levels of total lipid in the copepods increased with depth at a rate of around 100 μg per 100 m depth between 200 and 1000 m. Fatty acid composition of the wax esters reflected that of the local prey community, with a spectrum of diatom to flagellate dominated profiles corresponding to different microplankton environments. Copepods with highest levels of total lipid also contained highest levels of the highly unsaturated diatom fatty acid biomarker 20:5(n-3), and occupied the deepest depths during diapause. In addition, unsaturation levels of both the fatty acid and fatty alcohol moieties of the wax esters in the copepods increased with depth. This has implications for the buoyancy of these organisms: higher unsaturation makes the lipid likely to change from liquid to solid state at overwintering depths, increasing their specific gravity. These findings emphasise functional role of n-3 fatty acids in the diapause life-phase of calanoid copepods and in particular the importance of fatty acids from diatoms for overwintering.

  7. Ingestion and sublethal effects of physically and chemically dispersed crude oil on marine planktonic copepods.

    PubMed

    Almeda, Rodrigo; Baca, Sarah; Hyatt, Cammie; Buskey, Edward J

    2014-08-01

    Planktonic copepods play a key function in marine ecosystems, however, little is known about the effects of dispersants and chemically dispersed crude oil on these important planktonic organisms. We examined the potential for the copepods Acartia tonsa, Temora turbinata and Parvocalanus crassirostris to ingest crude oil droplets and determined the acute toxicity of the dispersant Corexit() 9500A, and physically and chemically dispersed crude oil to these copepods. We detected ingestion of crude oil droplets by adults and nauplii of the three copepod species. Exposure to crude oil alone (1 L L(-1), 48 h) caused a reduction of egg production rates (EPRs) by 26-39 %, fecal pellet production rates (PPRs) by 11-27 %, and egg hatching (EH) by 1-38 % compared to the controls, depending on the species. Dispersant alone (0.05 L L(-1), 48 h) produced a reduction in EPR, PPR and EH by 20-35, 12-23 and 2-11 %, respectively. Dispersant-treated crude oil was the most toxic treatment, ~1.6 times more toxic than crude oil alone, causing a reduction in EPR, PPR and EH by 45-54, 28-41 and 11-31 %, respectively. Our results indicate that low concentrations of dispersant Corexit 9500A and chemically dispersed crude oil are toxic to marine zooplankton, and that the ingestion of crude oil droplets by copepods may be an important route by which crude oil pollution can enter marine food webs. PMID:24756329

  8. Long-term change in the copepod community in the southern German Bight

    NASA Astrophysics Data System (ADS)

    Boersma, Maarten; Wiltshire, Karen H.; Kong, Sopha-Mith; Greve, Wulf; Renz, Jasmin

    2015-07-01

    The North Sea has undergone considerable change in recent years, with several reported regime shifts in the last decades, the most recent of which is thought to have occurred in the final years of the last century. As biological evidence corroborating this most recent regime shift is still rare, we investigated the reaction of the copepod community of the Helgoland Roads sampling site to this perceived shift. We observed that the densities of calanoid copepods have declined to values which are roughly 25% of the peak densities in the mid 1980s and link the decrease to the decreasing nutrient inputs into the North Sea. The initial increase in the densities of non-calanoid copepods seems to have reversed, and currently most of the copepods of the community in the southern North Sea are below their long-term average. These strong declines in densities could have major consequences for recruitment of higher trophic levels. We expect a stronger dependence of copepod densities to the larger oceanographic phenomena such as inflows of Atlantic water into the North Sea, as now that the large anthropogenic riverine inputs of nitrogen and phosphorus have decreased and these inflows were the main source of nutrients into the North Sea.

  9. Effects of rotifers, copepods and chironomid larvae on microbial communities in peatlands.

    PubMed

    Mieczan, Tomasz; Nied?wiecki, Micha?; Tarkowska-Kukuryk, Monika

    2015-10-01

    Interactions between the microbial loop and the classical grazing food chain are essential to ecosystem ecology. The goal of the present study was to examine the impact of chironomid larvae, rotifers and copepods on the major components of the microbial food web (algae, bacteria, heterotrophic flagellates, testate amoebae and ciliates) in peatlands. Two enclosure experiments were carried out in a Sphagnum peatland. In the experiments we manipulated rotifers, copepods and macroinvertebrates, i.e. chironomid larvae (Psectrocladius sordidellus gr). During the experiments variation was observed in the abundance of potential predators. The beginning of the first experiment was distinguished by dominance of rotifers, but five days later copepods were dominant. In the second experiment copepods dominated. The results of this study are the first to suggest a substantial impact of chironomid larvae, rotifers and copepods on microorganism communities in peatland ecosystems. The impact is reflected by both a decrease in the abundance and biomass of testate amoebae and ciliates and a transformation of the size structure of bacteria. Heterotrophic flagellates (HNF) were not controlled by metazoans, but rather by testate amoebae and ciliates, as HNF were more abundant in the control treatment. PMID:26322497

  10. Strain-related physiological and behavioral effects of Skeletonema marinoi on three common planktonic copepods.

    PubMed

    Md Amin, Roswati; Koski, Marja; Bmstedt, Ulf; Vidoudez, Charles

    2011-01-01

    Three strains of the chain-forming diatom Skeletonema marinoi, differing in their production of polyunsaturated aldehydes (PUA) and nutritional food components, were used in experiments on feeding, egg production, hatching success, pellet production, and behavior of three common planktonic copepods: Acartia tonsa, Pseudocalanus elongatus, and Temora longicornis. The three different diatom strains (9B, 1G, and 7J) induced widely different effects on Acartia tonsa physiology, and the 9B strain induced different effects for the three copepods. In contrast, different strains induced no or small alterations in the distribution, swimming behavior, and turning frequency of the copepods. 22:6(n-3) fatty acid (DHA) and sterol content of the diet typically showed a positive effect on either egg production (A. tonsa) or hatching success (P. elongatus), while other measured compounds (PUA, other long-chain polyunsaturated fatty acids) of the algae had no obvious effects. Our results demonstrate that differences between strains of a given diatom species can generate effects on copepod physiology, which are as large as those induced by different algae species or groups. This emphasizes the need to identify the specific characteristics of local diatoms together with the interacting effects of different mineral, biochemical, and toxic compounds and their potential implications on different copepod species. PMID:24391269

  11. Induction of domoic acid production in the toxic diatom Pseudo-nitzschia seriata by calanoid copepods.

    PubMed

    Tammilehto, Anna; Nielsen, Torkel Gissel; Krock, Bernd; Mller, Eva Friis; Lundholm, Nina

    2015-02-01

    The toxic diatom Pseudo-nitzschia seriata was exposed directly and indirectly (separated by a membrane) to copepods, Calanus hyperboreus and C. finmarchicus, to evaluate the effects of the copepods on domoic acid production and chain formation in P. seriata. The toxicity of P. seriata increased in the presence of the copepods. This response was chemically mediated without physical contact between the organisms suggesting that it was induced by potential waterborne cues from the copepods or changes in water chemistry. Domoic acid production may be related to defense against grazing in P. seriata although it was not shown in the present study. To evaluate if the induction of domoic acid production was mediated by the chemical cues from damaged P. seriata cells, live P. seriata cells were exposed to a P. seriata cell homogenate, but no effect was observed. Chain formation in P. seriata was affected only when in direct contact with the copepods. This study suggests that the presence of zooplankton may be one of the factors affecting the toxicity of Pseudo-nitzschia blooms in the field. PMID:25521565

  12. Direct examination of the dietary preference of the copepod calanus helgolandicus using the colorimetric approach

    NASA Astrophysics Data System (ADS)

    Kang, Hyung-Ku; Poulet, Serge; Ju, Se-Jong

    2007-09-01

    The food selectivity of tethered females of the copepod Calanus helgolandicus was examined by using the colorimetric approach. First, feeding behavior of the copepod did not show any differences between the red-color stained with neutral red and non-stained diets using the diatom Coscinodiscus curvatulus. Then, the copepods were fed a mixtures of two diets, the diatom C. curvatulus, stained with neutral red, and the dinoflagellate Gymnodinium sanguineum for 14~60 minutes of feeding duration. The foregut colors of females were examined using a stereo-microscope and a video monitor. The foreguts of animals fed with a high density of diatoms in mixed diets showed a dark red color, whereas those fed with a high density of dinoflagellate in mixed diets were a dark yellow. The results suggest that this species of copepod may not selectively feed either one of the diets used for this study. Their feeding activity may be more likely related to the density of available prey in their environment. Therefore, this quick and easy colorimetric approach could provide very useful information, like the pre-screening procedure before designing and conducting the time-consuming and complex feeding experiments to understand the feeding ecology of copepods.

  13. A marine diatom-derived aldehyde induces apoptosis in copepod and sea urchin embryos.

    PubMed

    Romano, Giovanna; Russo, Gian Luigi; Buttino, Isabella; Ianora, Adrianna; Miralto, Antonio

    2003-10-01

    The diatom-derived aldehyde 2-trans-4-trans-decadienal (DD) was tested as an apoptogenic inducer in both copepod and sea urchin embryos, using terminal-deoxynucleotidyl-transferase-mediated dUTP nick-end labelling (TUNEL), DNA fragmentation profiling (laddering) and an assay for caspase-3 activity. DD induced TUNEL positivity and DNA laddering, but not caspase-like activation, in copepod embryos spawned by females fed for 10-15 days the diatom diet Thalassiosira rotula Meunier (in vivo), or when newly spawned eggs were exposed for 1 h to 5 micro g ml(-1) DD (in vitro). To our knowledge, this is the first time that evidence for an apoptotic process in copepods has been obtained by cytochemical (TUNEL) and biochemical (DNA fragmentation) approaches. The absence of caspase-like activity in copepod embryos suggests that caspase-independent programmed cell death occurs in these organisms. In sea urchin embryos, DD induced apoptosis and also activated a caspase-3-like protease. The saturated aldehyde decanal induced apoptosis at higher concentrations and after a longer incubation period than DD, indicating that alpha,beta-unsaturation of the molecule, coupled with the aldehyde group, is responsible for the greater biological activity of DD. Since diatoms are an important food source for marine herbivores such as copepods and sea urchins, these findings may help explain why unsaturated aldehydes often induce reproductive failure, with important ecological consequences at the population level. PMID:12939379

  14. Mesozooplankton composition, biomass and vertical distribution, and copepod production in the stratified central north sea

    NASA Astrophysics Data System (ADS)

    Fransz, H. G.; Miquel, J. C.; Gonzalez, S. R.

    During three cruises to the Oyster Ground area in the central North Sea in 1981 the animal plankton was sampled at different depths by oblique hauls with a net and in 30 litre bottles. Copepods dominated, but echinopluteus larvae were equally numerous in July. Hydromedusae were the most abundant carnivores. Mean total biomass ADW estimates of herbivores amounted to 1.7, 5.8, and 2.9 g·m -2 in May, July and September, respectively, including 1.3, 2.3, and 1.5 g·m -2 of copepods. The carnivore biomass was 0.3 g·m -2 in May, 0.6 in July, and 0.8 in September. The vertical distribution of calanoid copepods followed the distribution of chlorophyll rather than particulate carbon. The copepod carbon production, calculated from biomass figures and literature growth parameters and extrapolated for the period May to October, amounted to at most 9 g·m -2. This does not exceed comparable values found for the isothermal Southern Bight of the North Sea. A positive influence of thermal stratification on the ratio of copepod production and primary production was not found.

  15. Modeling the impacts of multiple environmental stress factors on estuarine copepod populations.

    PubMed

    Korsman, John C; Schipper, Aafke M; De Hoop, Lisette; Mialet, Benoit; Maris, Tom; Tackx, Micky L M; Hendriks, A Jan

    2014-05-20

    Many studies have focused on natural stress factors that shape the spatial and temporal distribution of calanoid copepods, but bioassays have shown that copepods are also sensitive to a broad range of contaminants. Although both anthropogenic and natural stress factors are obviously at play in natural copepod communities, most studies consider only one or the other. In the present investigation, we modeled the combined impact of both anthropogenic and natural stress factors on copepod populations. The model was applied to estimate Eurytemora affinis densities in the contaminated Scheldt estuary and the relatively uncontaminated Dar-Zingst estuary in relation to temperature, salinity, chlorophyll a, and sediment concentrations of cadmium, copper, and zinc. The results indicated that temperature was largely responsible for seasonal fluctuations of E. affinis densities. Our model results further suggested that exposure to zinc and copper was largely responsible for the reduced population densities in the contaminated estuary. The model provides a consistent framework for integrating and quantifying the impacts of multiple anthropogenic and natural stress factors on copepod populations. It facilitates the extrapolation of laboratory experiments to ecologically relevant end points pertaining to population viability. PMID:24758200

  16. Size relationships between the parasitic copepod, Lernanthropus cynoscicola , and its fish host, Cynoscion guatucupa.

    PubMed

    Timi, J T; Lanfranchi, A L

    2006-02-01

    The effects of the size of Cynoscion guatucupa on the size and demographic parameters of their parasitic copepod Lernanthropus cynoscicola were evaluated. Prevalence of copepods increased with host size up to fish of intermediate length, then it decreased, probably because changes in size of gill filaments affect their attachment capability, enhancing the possibility of being detached by respiratory currents. Body length of copepods was significantly correlated with host length, indicating that only parasites of an 'adequate' size can be securely attached to a fish of a given size. The absence of relationship between the coefficient of variability in copepod length and both host length and number of conspecifics, together with the host-size dependence of both male and juvenile female sizes, prevent to interpret this relationship as a phenomenon of developmental plasticity. Therefore, the observed peak of prevalence could reflect the distribution of size frequencies in the population of copepods, with more individuals near the average length. Concluding, the 'optimum' host size for L. cynoscicola could merely be the adequate size for most individuals in the population, depending, therefore, on a populational attribute of parasites. However, its location along the host size range could be determined by a balance between fecundity and number of available hosts, which increases and decreases, respectively, with both host and parasite size. PMID:16472414

  17. The impact of polystyrene microplastics on feeding, function and fecundity in the marine copepod Calanus helgolandicus.

    PubMed

    Cole, Matthew; Lindeque, Pennie; Fileman, Elaine; Halsband, Claudia; Galloway, Tamara S

    2015-01-20

    Microscopic plastic debris, termed microplastics, are of increasing environmental concern. Recent studies have demonstrated that a range of zooplankton, including copepods, can ingest microplastics. Copepods are a globally abundant class of zooplankton that form a key trophic link between primary producers and higher trophic marine organisms. Here we demonstrate that ingestion of microplastics can significantly alter the feeding capacity of the pelagic copepod Calanus helgolandicus. Exposed to 20 ?m polystyrene beads (75 microplastics mL(1)) and cultured algae ([250 ?g C L(1)) for 24 h, C. helgolandicus ingested 11% fewer algal cells (P = 0.33) and 40% less carbon biomass (P < 0.01). There was a net downward shift in the mean size of algal prey consumed (P < 0.001), with a 3.6 fold increase in ingestion rate for the smallest size class of algal prey (11.612.6 ?m), suggestive of postcapture or postingestion rejection. Prolonged exposure to polystyrene microplastics significantly decreased reproductive output, but there were no significant differences in egg production rates, respiration or survival. We constructed a conceptual energetic (carbon) budget showing that microplastic-exposed copepods suffer energetic depletion over time. We conclude that microplastics impede feeding in copepods, which over time could lead to sustained reductions in ingested carbon biomass. PMID:25563688

  18. Climate change affects low trophic level marine consumers: warming decreases copepod size and abundance.

    PubMed

    Garzke, Jessica; Ismar, Stefanie M H; Sommer, Ulrich

    2015-03-01

    Concern about climate change has re-ignited interest in universal ecological responses to temperature variations: (1) biogeographical shifts, (2) phenology changes, and (3) size shifts. In this study we used copepods as model organisms to study size responses to temperature because of their central role in the pelagic food web and because of the ontogenetic length constancy between molts, which facilitates the definition of size of distinct developmental stages. In order to test the expected temperature-induced shifts towards smaller body size and lower abundances under warming conditions, a mesocosm experiment using plankton from the Baltic Sea at three temperature levels (ambient, ambient +4C, ambient -4C) was performed in summer 2010. Overall copepod and copepodit abundances, copepod size at all life stages, and adult copepod size in particular, showed significant temperature effects. As expected, zooplankton peak abundance was lower in warm than in ambient treatments. Copepod size-at-immature stage significantly increased in cold treatments, while adult size significantly decreased in warm treatments. PMID:25413864

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

    NASA Astrophysics Data System (ADS)

    Sandulli, R.; Pinckney, J.

    1999-05-01

    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.

  20. Copepod communities, production and grazing in the Turkish Straits System and the adjacent northern Aegean Sea during spring

    NASA Astrophysics Data System (ADS)

    Zervoudaki, S.; Christou, E. D.; Assimakopoulou, G.; rek, H.; Gucu, A. C.; Giannakourou, A.; Pitta, P.; Terbiyik, T.; Y?cel, N.; Moutsopoulos, T.; Pagou, K.; Psarra, S.; zsoy, E.; Papathanassiou, E.

    2011-06-01

    The Mediterranean and the Black Seas are connected through Bosphorus, Marmara Sea and Dardanelles (Turkish Straits System, TSS). In this study, we examined the spatial distribution of copepods and investigate their production and grazing. The aim was to understand the transfer of phytoplankton/microzooplankton production up the food chain in TSS and Aegean Sea during spring. The phytoplankton and microzooplankton biomass and production showed a clear decreasing trend from Bosphorus to the Aegean Sea, whereas copepod biomass did not reveal any distinct trend and only the number of copepod species increased from Bosphorus to the Aegean Sea. Production of copepods and egg production showed similar trends except for the Bosphorus, where production of copepods was very low due to the low copepod biomass in this area. In all areas, the copepod carbon demand was largely met by phytoplankton and microzooplankton production. However, only a low amount of primary production was consumed by copepods and production appeared to flow mostly through other pathways (microbial loop) and/or sediment on the bottom. The results of this study confirm the hypothesis that there is a substantial differentiation within pelagic food web structure and carbon flow from Bosphorus to the Aegean Sea.

  1. 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...

  2. Vertical migration and positioning behavior of copepods in a mangrove estuary: Interactions between tidal, diel light and lunar cycles

    NASA Astrophysics Data System (ADS)

    Chew, Li-Lee; Chong, Ving Ching; Ooi, Ai Lin; Sasekumar, A.

    2015-01-01

    Two-hourly zooplankton samplings encompassing tidal (semi-diurnal), diel (24 h), and lunar (4 phases) cycles during the dry (July 2003) and wet (November 2003) monsoon periods were conducted in the Matang estuary to investigate the vertical distribution and behavior of five different groups of copepods (estuarine, euryhaline, marine euryhaline, stenohaline and nocturnal pontellids) in response to the tidal and light regime. Diel vertical migration (DVM) was evident for all copepod groups but the observed patterns differed among species and sampling period (wet or dry and neap or spring tide). Tidally-induced vertical migration (TVM), superimposed by DVM, was observed for estuarine, marine euryhaline and stenohaline copepods but not for euryhaline and nocturnal pontellid copepods. Estuarine copepods tended to ascend during night-flood tide and descent to the bottom during day-ebb tide; this suggests a selective mechanism to penetrate upstream and maintain position in the estuary. In contrast, the marine euryhaline and stenohaline copepods remained at the bottom especially during day-flood tide and ascended into the water column during night-ebb tide; this suggests a selective mechanism to avoid upstream transport. Euryhaline copepods did not respond to tidal advection probably due to their wide range of salinity tolerance, while the large nocturnal pontellid copepods have strong swimming ability. Adaptive vertical migration appears to be a major factor structuring the copepod community in tropical estuaries, and its occurrence in most copepods suggests that neritic marine zooplankton tidally-advected into estuaries and nearshore waters can survive better than previously thought.

  3. DNA barcoding of marine copepods: assessment of analytical approaches to species identification.

    PubMed

    Blanco-Bercial, Leocadio; Cornils, Astrid; Copley, Nancy; Bucklin, Ann

    2014-01-01

    More than 2,500 species of copepods (Class Maxillopoda; Subclass Copepoda) occur in the marine planktonic environment. The exceptional morphological conservation of the group, with numerous sibling species groups, makes the identification of species challenging, even for expert taxonomists. Molecular approaches to species identification have allowed rapid detection, discrimination, and identification of species based on DNA sequencing of single specimens and environmental samples. Despite the recent development of diverse genetic and genomic markers, the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) gene remains a useful and - in some cases - unequaled diagnostic character for species-level identification of copepods. This study reports 800 new barcode sequences for 63 copepod species not included in any previous study and examines the reliability and resolution of diverse statistical approaches to species identification based upon a dataset of 1,381 barcode sequences for 195 copepod species. We explore the impact of missing data (i.e., species not represented in the barcode database) on the accuracy and reliability of species identifications. Among the tested approaches, the best close match analysis resulted in accurate identification of all individuals to species, with no errors (false positives), and out-performed automated tree-based or BLAST based analyses. This comparative analysis yields new understanding of the strengths and weaknesses of DNA barcoding and confirms the value of DNA barcodes for species identification of copepods, including both individual specimens and bulk samples. Continued integrative morphological-molecular taxonomic analysis is needed to produce a taxonomically-comprehensive database of barcode sequences for all species of marine copepods. PMID:24987576

  4. Occurrence of the parasitic copepod Ergasilus labracis on Threespine Sticklebacks from the south coast of Newfoundland.

    PubMed

    Eaves, Alexandra A; Ang, Keng Pee; Murray, Harry M

    2014-12-01

    A study conducted from August to October 2013 surveyed Threespine Sticklebacks Gasterosteus aculeatus (n = 822) for the presence of parasitic copepods in the vicinity of large sea-cage salmonid farms in Bay d'Espoir, Newfoundland. The majority of parasitic copepods surveyed were Ergasilus labracis (n = 4,684). Other parasitic copepods observed on Threespine Sticklebacks during the survey included chalimus-stage Lepeophtheirus spp. (n = 3), adult Argulus alosae (n = 2), and a single Thersitina gasterostei. This represents a new host record for E. labracis. The copepods were present on fish collected in a broad range of temperatures (6.9-17.7C) and salinities (10.2-30.2 [Practical Salinity Scale]). The parasitic copepods were most commonly found on larger hosts estimated to be age 1 or older. Surprisingly, the highest infestations (approximately 65%) were found on regions of the hosts outside of the gills (behind the pectoral fins and pelvic spines); in some cases, the copepods had inflicted significant damage to the skin of their hosts. Among host fish with evidence of an additional infection, such as microsporidian tumors (xenomas) or hemorrhagic-like symptoms (dark red abdomens and bloody mucus), the prevalence of E. labracis was significantly higher (43.4%) than among healthy fish (28.9%) despite there being no significant difference in size between the two fish health groups. In contrast, intensity (mean number of individual parasites per host) was significantly higher among healthy hosts (23.6) than among unhealthy ones (7.63). Although this parasite has been listed as present in Newfoundland previously, it has a broad host range and has been reported to be pathogenic to farmed salmonids. Therefore, its potential impact on wild and farmed fish populations around Newfoundland should not be underestimated. PMID:25321153

  5. DNA Barcoding of Marine Copepods: Assessment of Analytical Approaches to Species Identification

    PubMed Central

    Blanco-Bercial, Leocadio; Cornils, Astrid; Copley, Nancy; Bucklin, Ann

    2014-01-01

    More than 2,500 species of copepods (Class Maxillopoda; Subclass Copepoda) occur in the marine planktonic environment. The exceptional morphological conservation of the group, with numerous sibling species groups, makes the identification of species challenging, even for expert taxonomists. Molecular approaches to species identification have allowed rapid detection, discrimination, and identification of species based on DNA sequencing of single specimens and environmental samples. Despite the recent development of diverse genetic and genomic markers, the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) gene remains a useful and in some cases unequaled diagnostic character for species-level identification of copepods. This study reports 800 new barcode sequences for 63 copepod species not included in any previous study and examines the reliability and resolution of diverse statistical approaches to species identification based upon a dataset of 1,381 barcode sequences for 195 copepod species. We explore the impact of missing data (i.e., species not represented in the barcode database) on the accuracy and reliability of species identifications. Among the tested approaches, the best close match analysis resulted in accurate identification of all individuals to species, with no errors (false positives), and out-performed automated tree-based or BLAST based analyses. This comparative analysis yields new understanding of the strengths and weaknesses of DNA barcoding and confirms the value of DNA barcodes for species identification of copepods, including both individual specimens and bulk samples. Continued integrative morphological-molecular taxonomic analysis is needed to produce a taxonomically-comprehensive database of barcode sequences for all species of marine copepods. PMID:24987576

  6. Prevalence of the parasitic copepod Haemobaphes intermedius on juvenile buffalo sculpins from Washington State

    USGS Publications Warehouse

    Halpenny, C.M.; Kocan, R.M.; Hershberger, P.K.

    2004-01-01

    The parasitic copepod, Haemobaphes intermedius, was detected in 62% of juvenile buffalo sculpins Enophrys bison, a previously unreported host, from the San Juan Islands archipelago in Washington State. Most infestations were characterized by the presence of a single female copepod infestations with multiple H. intermedius occurred either unilaterally or bilaterally in 29% of parasitized individuals. Impaired condition of parasitized hosts was indicated by significantly lower total lengths and weights (34.9 mm; 1.6 g) than in unparasitized cohorts (38.9 mm; 2.1 g). Host specificity was indicated by the failure to detect H. intermedius in 43 sympatric great sculpins Myoxocephalus polyacanthocephalus from the same location.

  7. Tumour-like anomaly of copepods-an evaluation of the possible causes in Indian marine waters.

    PubMed

    Jagadeesan, L; Jyothibabu, R

    2016-04-01

    Globally, tumour-like anomalies (TLA) in copepods and the critical assessment of their possible causes are rare. The exact causative factor and ecological consequences of TLA in copepods are still unclear and there is no quantitative data available so far to prove conclusively the mechanism involved in developing TLA in copepods. TLA in copepods are considered as a potential threat to the well-being of the aquatic food web, which prompted us to assess these abnormalities in Indian marine waters and assess the possible etiological agents. We carried out a focused study on copepods collected from 10 estuarine inlets and five coastal waters of India using a FlowCAM, advanced microscopes and laboratory-incubated observations. The analysis confirmed the presence of TLA in copepods with varying percentage of incidence in different environments. TLA was recorded in 24 species of copepods, which constituted ~1-15 % of the community in different environments. TLA was encountered more frequently in dominant copepods and exhibited diverse morphology; ~60 % was round, dark and granular, whereas ~20 % was round/oval, transparent and non-granular. TLA was mostly found in the dorsal and lateral regions of the prosome of copepods. The three suggested reasons/assumptions about the causes of TLA such as ecto-parasitism (Ellobiopsis infection), endo-parasitism (Blastodinium infection) and epibiont infections (Zoothamnium and Acineta) were assessed in the present study. We did find infections of endo-parasite Blastodinium, ecto-parasite Ellobiopsis and epibiont Zoothamnium and Acineta in copepods, but these infectious percentages were found <1.5 % to the total density and most of them are species specific. Detailed microscopical observations of the samples collected and the results of the incubation experiments of infected copepods revealed that ecto-parasitism, endo-parasitism and epibiont infections have less relevance to the formation of TLA in copepods. On the other hand, these studies corroborated the view that wounds on the exoskeleton caused by partial predation as the potential reason for the TLA of copepods in Indian waters. PMID:27010709

  8. Latitudinal metazoan plankton zones in the antarctic circumpolar current along 6W during austral spring 1992

    NASA Astrophysics Data System (ADS)

    Fransz, H. G.; Gonzalez, S. R.

    During the ANT X/6 cruise of R.V. Polarstern as a part of Southern Ocean JGOFS, the mesozooplankton and smaller metazoans were sampled from five depth layers between 0 and 500 m, and daily egg production was measured in copepods. The latitudinal and vertical abundance, biomass and species distribution were recorded twice along the 6W meridian between the Weddell Gyre and the Polar Frontal Zone in October and November 1992. Carbon weight-length relationships are presented for the dominant copepod species Calanoides acutus, Rhincalanus gigas, Metridia gerlachei and Oithona similis. Total biomass measured by weighing filters of two size fractions and calculated from specific abundance and length estimations both averaged to about 5 g ashfree dry weight (AFDW) per m 2 in the Polar Frontal region (PFr), somewhat lower in October than in November, and 2 g AFDW m -2 in the Antarctic Zone (AZ) between the PFr and the Weddell Gyre. Antarctic calanoid copepods as a group dominated biomass in both regions, but the cyclopoid copepod Oithona similis had the highest numerical abundance and in general also the highest biomass of all species. Mean copepodid abundance below 100 m was not different in the PFr and the AZ, but the abundance in the upper 100 m was much higher in the PFr. Daily egg production of Calanoides acutus was highest in the PFr. The community composition in the PFr and the AZ indicated that accumulation in the Antarctic convergence or a difference in timing of the spring rise to the surface was not the main cause of the latitudinal spring peak in the PFr. Probably the physical conditions are most favourable here for zooplankton to sustain populations. This seems most advantageous for species with a long reproductive period, allowing them to produce several generations per year. Life cycle strategies of Antarctic zooplankton species only can be compared in the framework of their specific conditions for growth and persistence in different latitudinal zones, and the distribution and transport patterns of their populations.

  9. A new copepod (Siphonostomatoida: Lernanthropidae) parasitic on a Red Sea immigrant dragonet (Actinopterygii: Callionymidae), with a review of records of parasitic copepods from dragonets.

    PubMed

    El-Rashidy, Hoda H; Boxshall, Geoff A

    2012-02-01

    A new species of parasitic copepod of the family Lernanthropidae is described from an immigrant population of the blotchfin dragonet Callionymus filamentosus Valenciennes (family Callionymidae) in the Eastern Mediterranean. Both sexes are described on the basis of material caught in Egyptian waters off the Alexandria coast at Abuqir. The new species shares with Lernanthropus breviculus Kabata, 1979 the possession of a small dorsal plate on the trunk that is so narrow at its origin that it does not overlap the bases of the fourth legs, which are therefore visible in dorsal view. These species differ in the shape of the cephalothorax and in the extent of the dorsal plate, which is shorter in the new species, revealing the caudal rami in dorsal view. Previous records of parasitic copepods utilising callionymids as hosts are reviewed: most belong to the families Pennellidae and Chondracanthidae. PMID:22183918

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

    PubMed

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

    2014-02-01

    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

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

    PubMed Central

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

    2012-01-01

    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

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

    PubMed Central

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

    2014-01-01

    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

  13. Accumulation of polyunsaturated aldehydes in the gonads of the copepod Acartia tonsa revealed by tailored fluorescent probes.

    PubMed

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

    2014-01-01

    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

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

    PubMed

    Hirose, Euichi; Uyeno, Daisuke

    2014-08-01

    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

  15. How much crude oil can zooplankton ingest? Estimating the quantity of dispersed crude oil defecated by planktonic copepods.

    PubMed

    Almeda, Rodrigo; Connelly, Tara L; Buskey, Edward J

    2016-01-01

    We investigated and quantified defecation rates of crude oil by 3 species of marine planktonic copepods (Temora turbinata, Acartia tonsa, and Parvocalanus crassirostris) and a natural copepod assemblage after exposure to mechanically or chemically dispersed crude oil. Between 88 and 100% of the analyzed fecal pellets from three species of copepods and a natural copepod assemblage exposed for 48 h to physically or chemically dispersed light crude oil contained crude oil droplets. Crude oil droplets inside fecal pellets were smaller (median diameter: 2.4-3.5 μm) than droplets in the physically and chemically dispersed oil emulsions (median diameter: 6.6 and 8.0 μm, respectively). This suggests that copepods can reject large crude oil droplets or that crude oil droplets are broken into smaller oil droplets before or during ingestion. Depending on the species and experimental treatments, crude oil defecation rates ranged from 5.3 to 245 ng-oil copepod(-1) d(-1), which represent a mean weight-specific defecation rate of 0.026 μg-oil μg-Ccopepod(1) d(-1). Considering a dispersed crude oil concentration commonly found in the water column after oil spills (1 μl L(-1)) and copepod abundances in high productive coastal areas, copepods may defecate ∼1.3-2.6 mg-oil m(-3) d(-1), which would represent ∼0.15%-0.30% of the total dispersed oil per day. Our results indicate that ingestion and subsequent defecation of crude oil by planktonic copepods has a small influence on the overall mass of oil spills in the short term, but may be quantitatively important in the flux of oil from surface water to sediments and in the transfer of low-solubility, toxic petroleum hydrocarbons into food webs after crude oil spills in the sea. PMID:26586632

  16. Temporal variation in copepod abundance and composition in a strong, persistent coastal upwelling zone

    NASA Astrophysics Data System (ADS)

    Fontana, Rachel E.; Elliott, Meredith L.; Largier, John L.; Jahncke, Jaime

    2016-03-01

    Zooplankton abundance and species composition provide information on environmental variability in the ocean. While zooplankton time series span the west coast of North America, less data exist off north-central California. Here, we investigated a zooplankton time series, focusing specifically on copepods, collected within the Gulf of the Farallones-Cordell Bank area (37.5° to 38.5°N) from 2004 to 2009. Impacted by seasonally strong, persistent upwelling, this study area is located downstream of a major upwelling center (Point Arena). We found copepod abundance and species composition differed significantly, particularly between the first three years (2004-2006) and the latter three years (2007-2009) of the study. These changes were mainly observed as changes in abundance of boreal copepod species, Pseudocalanus mimus and Acartia longiremis. These taxa showed increasing abundances for the latter three years of the study (2007-2009). During the first three years of the time series, environmental measurements in the region showed lower alongshore wind stress, weaker upwelling, minimal surface alongshore flow, and warmer surface ocean temperatures. Temporal variations in copepod abundance and species composition correlated with several of these environmental measurements (e.g., surface cross-shore and alongshore flows, upwelling, and alongshore wind stress), indicating environmental forcing of primary consumers and ecosystem productivity in this strong, persistent upwelling zone.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

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

    PubMed

    Vehmaa, Anu; Hogfors, Hedvig; Gorokhova, Elena; Brutemark, Andreas; Holmborn, Towe; Engstrm-st, Jonna

    2013-11-01

    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

  19. Solid phase extraction and metabolic profiling of exudates from living copepods.

    PubMed

    Selander, Erik; Heuschele, Jan; Nylund, Gran M; Pohnert, Georg; Pavia, Henrik; Bjrke, Oda; Pender-Healy, Larisa A; Tiselius, Peter; Kirboe, Thomas

    2016-01-01

    Copepods are ubiquitous in aquatic habitats. They exude bioactive compounds that mediate mate finding or induce defensive traits in prey organisms. However, little is known about the chemical nature of the copepod exometabolome that contributes to the chemical landscape in pelagic habitats. Here we describe the development of a closed loop solid phase extraction setup that allows for extraction of exuded metabolites from live copepods. We captured exudates from male and female Temora longicornis and analyzed the content with high resolution LC-MS. Chemometric methods revealed 87 compounds that constitute a specific chemical pattern either qualitatively or quantitatively indicating copepod presence. The majority of the compounds were present in both female and male exudates, but nine compounds were mainly or exclusively present in female exudates and hence potential pheromone candidates. Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude that solid phase extraction in combination with metabolic profiling of exudates is a useful tool to develop our understanding of the chemical interplay between pelagic organisms. PMID:26788422

  20. First records of parasitic copepods (Crustacea, Siphonostomatoida) from marine fishes in Korea.

    PubMed

    Venmathi Maran, B A; Soh, H Y; Hwang, U W; Chang, C Y; Myoung, J G

    2015-06-01

    The knowledge of the biodiversity of parasitic copepods in South Korea is increasing. Interestingly we report here, some parasitic copepods considered as the first record of findings from Korea. Nine species of parasitic copepods (Siphonostomatoida) including six genera of three different families [Caligidae (7), Lernaeopodidae (1), Lernanthropidae (1)] were recovered from eight species of wild fishes in Korea: 1) Caligus hoplognathi Yamaguti & Yamasu, 1959 (?, ?) from the body surface of barred knifejaw Oplegnathus fasciatus (Temminck & Schlegel); 2) Caligus lagocephali Pillai, 1961 (?) from the gills of panther puffer Takifugu pardalis (Temminck & Schlegel); 3) Euryphorus brachypterus (Gerstaecker, 1853) (?, ?) from the opercular cavity of Atlantic bluefin tuna Thunnus thynnus (Linnaeus); 4) Euryphorus nordmanni Milne Edwards, 1840 (?, ?) from the opercular cavity of common dolphin fish Coryphaena hippurus Linnaeus; 5) Gloiopotes huttoni (Thomson) (?, ?) from the body surface of black marlin Istiompax indica (Cuvier); 6) Lepeophtheirus hapalogenyos Yamaguti & Yamasu, 1959 (?) from the gill filaments of O. fasciatus; 7) Lepeophtheirus sekii Yamaguti, 1936 (?, ?) from the body surface of red seabream Pagrus major (Temminck & Schlegel); 8) Brachiella thynni Cuvier, 1830 (?) from the body surface of longfin tuna or albacore Thunnus alalunga (Bonnaterre); 9) Lernanthropinus sphyraenae (Yamaguti & Yamasu, 1959) (?) from the gill filaments of moon fish Mene maculata (Bloch & Schneider). Since the female was already reported in Korea, it is a new record for the male of C. hoplognathi. A checklist for the parasitic copepods of the family Caligidae, Lernaeopodidae and Lernanthropidae of Korea is provided. PMID:26691264

  1. Large-scale forcing of environmental conditions on subarctic copepods in the northern California Current system

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Bi, Hongsheng; Peterson, William T.

    2015-05-01

    In the ocean, dominant physical processes often change at various spatial and temporal scales. Here, we examined associations between large-scale physical forcing indexed by the Pacific Decadal Oscillation (PDO), regional ocean conditions including alongshore currents in relation to the abundance of two subarctic oceanic copepods, Neocalanus plumchrus, and N. cristatus in the offshore portions of the northern California Current (NCC) system in spring of 1998-2008. We found significant relationships between the abundance of copepods, water temperature, and alongshore currents with a lag of two or four months in response to the PDO in the NCC system. During the growth season in March/April both subarctic copepod species displayed consistent cross-shelf patterns with shoreward decreasing gradient in abundance, and were negatively correlated with the PDO, sea water temperature, and alongshore currents. Our studies highlight the responses of regional ocean conditions to large-scale physical forcing and illustrate the potential for Neocalanus copepods as unique vectors for a new understanding of the ecological response in the offshore oceanic waters of the NCC system to climate variability.

  2. 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....

  3. Copepod community succession during warm season in Lagoon Notoro-ko, northeastern Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Nakagawa, Yoshizumi; Ichikawa, Hideaki; Kitamura, Mitsuaki; Nishino, Yasuto; Taniguchi, Akira

    2015-06-01

    Lagoon Notoro-ko, located on the northeastern coast of Hokkaido, Japan, and connected to the Okhotsk Sea by a human-made channel, is strongly influenced by local hydrography, as water masses in the lagoon are seasonally influenced by the Soya Warm Current and the East Sakhalin Current. We here report on the succession of copepod communities during the warm season in relation to water mass exchange. Copepods were categorized into four seasonal communities (spring/early-summer, mid-summer, late-summer/fall, and early-winter) via a cluster analysis based on Bray-Curtis similarities. Spring/early-summer and early-winter communities were characterized by the temperate-boreal calanoid Pseudocalanus newmani, comprising 34.9%-77.6% of the total abundance of copepods during times of low temperature/salinity, as influenced by the prevailing East Sakhalin Current. Late-summer/fall communities were characterized by the neritic warm-water calanoid Paracalanus parvus s.l., comprising 63.9%-96.3% of the total abundance, as influenced by the Soya Warm Current. Mid-summer communities comprised approximately equal abundances of P. parvus, Eurytemora herdmani, Scolecithricella minor, and Centropages abdominalis (12.8%-28.2%); this community is transitional between those of the spring/early-summer and late-summer/fall. Copepod community succession in Lagoon Notoro-ko can be largely explained by seasonal changes in water masses.

  4. IMPACT OF UV-B RADIATION ON THE FECUNDITY OF THE COPEPOD 'ACARTIA CLAUSII'

    EPA Science Inventory

    It has recently been demonstrated that acute midultraviolet irradiation (UV-B, 290 to 320 nm) of the marine copepod Acartia clausii results in reduced survival and fecundity. In the present study, immature late copepodites were separated by sex and exposed to three UV-B exposure ...

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

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

    PubMed Central

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

    2012-01-01

    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

  8. Solid phase extraction and metabolic profiling of exudates from living copepods

    PubMed Central

    Heuschele, Jan; Nylund, Göran M.; Pohnert, Georg; Pavia, Henrik; Bjærke, Oda; Pender-Healy, Larisa A.; Tiselius, Peter; Kiørboe, Thomas

    2016-01-01

    Copepods are ubiquitous in aquatic habitats. They exude bioactive compounds that mediate mate finding or induce defensive traits in prey organisms. However, little is known about the chemical nature of the copepod exometabolome that contributes to the chemical landscape in pelagic habitats. Here we describe the development of a closed loop solid phase extraction setup that allows for extraction of exuded metabolites from live copepods. We captured exudates from male and female Temora longicornis and analyzed the content with high resolution LC-MS. Chemometric methods revealed 87 compounds that constitute a specific chemical pattern either qualitatively or quantitatively indicating copepod presence. The majority of the compounds were present in both female and male exudates, but nine compounds were mainly or exclusively present in female exudates and hence potential pheromone candidates. Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude that solid phase extraction in combination with metabolic profiling of exudates is a useful tool to develop our understanding of the chemical interplay between pelagic organisms. PMID:26788422

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

    PubMed Central

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

    2013-01-01

    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

  10. Seasonal variability of meiofauna, especially harpacticoid copepods, in Posidonia oceanica macrophytodetritus accumulations

    NASA Astrophysics Data System (ADS)

    Mascart, Thibaud; Lepoint, Gilles; Deschoemaeker, Silke; Binard, Marc; Remy, François; De Troch, Marleen

    2015-01-01

    The overall aim of this study was (1) to assess the diversity and density of meiofauna taxa, especially harpacticoid copepod species, present within accumulated seagrass macrophytodetritus on unvegetated sand patches and (2) to elucidate the community structure of detritus-associated harpacticoid copepods in relation to natural temporal variability of physico-chemical characteristics of accumulations. This was investigated in a Posidonia oceanica (L.) Delile seagrass ecosystem in the northwest Mediterranean Sea (Bay of Calvi, Corsica, 42°35‧N, 8°43‧E) using a triplicate macrophytodetritus core field sampling in two contrasting sites over the four seasons of 2011. Meiofauna higher taxa consisted of 50% Copepoda, of which 87% belonged to the Harpacticoida order. Nematoda was the second most abundant taxa. The copepod community displayed a wide variety of morphologically similar and ecologically different species (i.e. mesopsammic, phytal, phytal-swimmers, planktonic and parasitic). The harpacticoid copepod community followed a strong seasonal pattern with highest abundances and species diversity in May-August, revealing a link with the leaf litter epiphyte primary production cycle. Aside from the important role in sheltering, housing and feeding potential of macrophytodetritus, a harpacticoid community BEST analysis demonstrated a positive correlation with habitat complexity and a negative correlation with water movements and P. oceanica leaf litter accumulation.

  11. Relationship between egg size and naupliar size in the calanoid copepod Diaptomus clavipes Schacht

    SciTech Connect

    Not Available

    1980-05-01

    A direct positive relationship was demonstrated between egg size and nauphar size in the calanoid copepod Diaptomus clavipes Schacht. Number of eggs per clutch and total clutch volume were inversely associated with measures of egg and naupliear size (egg volume, maximum egg length, nauplliar volume, and maximum naupliar length). Thus, small clutches with large eggs give rise to large nauplii.

  12. Relationship between egg size and naupliar size in the calanoid copepod Diaptomus clavipes Schacht

    SciTech Connect

    Cooney, J.D.; Gehrs, C.W.

    1980-01-01

    A direct positive relationship was demonstrated between egg size and naupliar size in the calanoid copepod Diaptomus clavipes Schacht. Number of eggs per clutch and total clutch volume were inversely associated with measures of egg and naupliar size (egg volume, maximum egg length, naupliar volume, and maximum naupliar length). Thus, small clutches with large eggs give rise to large nauplii.

  13. Egg production of the copepod Acartia hongi in Kyeonggi Bay, Korea

    NASA Astrophysics Data System (ADS)

    Youn, Seok Hyun; Choi, Joong Ki

    2007-09-01

    Many studies of copepod egg production have shown that food availability and temperature are major factors that influence copepod growth. However, coastal environments are complicated ecosystem and the relationships between growth of copepods and influencing factors are not always clear in nature. We conducted a study along an inner-middle-outer bay transect where variations in environmental parameters would be expected to affect the biomass and egg production rate of A. hongi from February 2001 to December 2001. In this study, we investigated the abundance and biomass with developmental stages and egg production rates of A. hongi in relation to various environmental factors. The copepod A. hongi occurred continuously throughout the year, with a peak abundance in May. In general, the variation in egg production rates showed a similar tendency with the variations in chlorophyll- a throughout the study period. This suggests that phytoplankton biomass is an important factor that affects the egg production of A. hongi. In addition, during the warm season, the egg production of A. hongi was also influenced by the ciliates abundance in the middle and outer bay. Consequently, the egg production of A. hongi is generally affected by food availability in Kyeonggi Bay.

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

    PubMed

    Sommer, Ulrich; Sommer, Frank; Santer, Barbara; Zllner, Eckart; Jrgens, Klaus; Jamieson, Colleen; Boersma, Maarten; Gocke, Klaus

    2003-05-01

    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 Schhsee (Germany) to logarithmically scaled abundance gradients of the microphagous cladoceran Daphnia hyalinaxgaleata and of a macrophagous copepod assemblage. Total phytoplankton biomass, chlorophyll a and primary production showed only a weak or even insignificant response to zooplankton density in both gradients. In contrast to the weak responses of bulk parameters, both zooplankton groups exerted a strong and contrasting influence on the phytoplankton species composition. The copepods suppressed large phytoplankton, while nanoplanktonic algae increased with increasing copepod density. Daphnia suppressed small algae, while larger species compensated in terms of biomass for the losses. Autotrophic picoplankton declined with zooplankton density in both gradients. Gelatinous, colonial algae were fostered by both zooplankton functional groups, while medium-sized (ca. 3,000 microm3), non-gelatinous algae were suppressed by both. The impact of a functionally mixed zooplankton assemblage became evident when Daphnia began to invade and grow in copepod mesocosms after ca. 10 days. Contrary to the impact of a single functional group, the combined impact of both zooplankton groups led to a substantial decline in total phytoplankton biomass. PMID:16228259

  15. Grazing pressure of copepods on the phytoplankton stock of the central North Sea

    NASA Astrophysics Data System (ADS)

    Baars, M. A.; Fransz, H. G.

    Measurements on gut fluorescence indicated that large stages of calanoid copepods ingested 6 times more chlorophyll containing particles by night than by day in the Oyster Ground area of the North Sea. No diurnal rhythm in chlorophyll pigment concentrations in the water was found in July and September. In May the chlorophyll a concentration was twice as high in the afternoon as after midnight, and ambient phaeopigment concentration showed an inverse rhythm but of small amplitude. During all 3 cruises total daily ingestion of chlorophyll by copepods was only a small fraction of ambient chlorophyll concentrations, and it is suggested that the observed rhythm in chlorophyll in May was caused not by grazing but by an internal physiological rhythm in the Cryptophyceae associated with Mesodinium. Chlorophyll ingestion and filtering rates measured in grazing experiments with labelled food were used to estimate the daily ration of phytoplankton carbon consumed by larger copepod stages. It was always low in Pseudocalanus and Calanus (4 to 8% of body carbon), higher in Temora and Centropages in May and September (25%). Respiration experiments showed that metabolic needs were 13%, 25% and 30% of body carbon per day in May (7C), July (15.5C) and September (17C). In July and September labile POC concentrations were low (44 and 77 mgm -3) and non-phytoplankton carbon formed the lesser part of it (14 and 39%, respectively). It is concluded that during summer most of the species studied were feeding below threshold concentrations, and, if not consuming detritus and microzooplankton, suffered from starvation. Biomass of calanoid copepods decreased from July to September, while other herbivorous species, probably more adapted to the phytoplankton composition, exceeded copepod biomass during these months. Extrapolation of the results on grazing by larger stages to the nauplii and small copepodites indicated that daily ingestion of phytoplankton carbon by the whole population of calanoid copepods decreased from 8% in May to less than 2% in September, corresponding with 14% and 3% of the particulate primary production respectively. Zooplankton respiration estimates indicated a higher grazing pressure for the total herbivorous zooplankton; in July 53% (22% by calanoid copepods) of primary production and in September 36% (10%). Herbivorous zooplankton, microheterotrophs and bottom fauna appeared to have an equal share in mineralization of primary products from May to September, but discrepancies between observed primary production, community respiration and the oxygen budget prevent a clear understanding of the carbon flow in this area of the North Sea in summer.

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

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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.

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

    PubMed Central

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

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

    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 infected, 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 fluorescence in situ hybridization (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 distribution of dinospores and nauplii argues against infection during the naupliar stage. Dinospores, described as autotrophic in the literature, may escape the severe nutrient limitation of ultra-oligotrophic ecosystems by living inside copepods.

  20. Hydrostatic pressure and temperature effects on the membranes of a seasonally migrating marine copepod.

    PubMed

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

    2014-01-01

    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

  1. Culture of harpacticoid copepods: potential as live feed for rearing marine fish.

    PubMed

    Cutts, Christopher J

    2003-01-01

    Copepods are useful as food for marine fish cultivation, in terms of both nutrition and ease of culture. Harpacticoid copepods are favoured over calanoids, since harpacticoids, as a result of their benthic habitat, can be reared at much higher densities. However, their benthic nature also makes mass culture difficult, since large surface areas must be provided. Within Harpacticoida, Tisbe spp. seem most useful, having high overall fecundity, and positive phototaxis of the nauplii. Harpacticoids can synthesise de novo several nutritionally important essential fatty acids (EFA), making them desirable as food for rearing marine fish. However, a diet rich in EFAs (e.g. animal derived feed) improves the productivity of copepod cultures, suggesting that the synthesis of EFA is rate-limiting for their reproduction. The nature of the substratum is also important in maintaining a good population, since harpacticoid biomass is more dependent on surface area than volume of a culture. Heterogeneous substrates can support large cultures because of their high surface area, but efficient cleaning methods are necessary. Frequent harvesting of populations will maintain good water quality and an overall low density of sexually mature copepods, raising naupliar productivity overall. Over-harvesting will naturally deplete the population. Harpacticoids are generally tolerant of environmental fluctuations but they do have temperature and salinity optima, and these will be species- and strain-dependent. Harpacticoid copepods are better food for fish larvae than Artemia, because of their ability to synthesise EFAs. The nauplii of harpacticoids are energetically poor but appear to have an appetite-stimulatory effect. Uneaten nauplii grow within the fish rearing tanks and graze on the walls, building up their own nutritional value and maintaining tank hygiene. PMID:12846044

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

    PubMed Central

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

    2012-01-01

    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

  3. The reproductive effort of Lepeophtheirus pectoralis (Copepoda: Caligidae): insights into the egg production strategy of parasitic copepods.

    PubMed

    Frade, D G; Santos, M J; Cavaleiro, F I

    2016-01-01

    The reproductive effort of Lepeophtheirus pectoralis (Müller O. F., 1776), a caligid copepod, which is commonly found infecting the European flounder, Platichthys flesus (Linnaeus, 1758), is studied in detail for the first time. Seasonal variation in body dimensions and reproductive effort are analysed. Data for 120 ovigerous females, 30 from each season of the year, were considered in the analyses. Females were larger and produced a larger number of smaller eggs in winter, than during the summer. The relationship between egg number and egg size is similar to that recorded for other copepods exploiting fish hosts. Much of the recorded variation was also similar to that reported for a copepod parasitic on an invertebrate host, which suggests the possibility of a general trend in copepod reproduction. Overall, our results provide further support for the hypothesis that there is an alternation of summer and winter generations. PMID:26549240

  4. Ingestion and regurgitation of living and inert materials by the estuarine copepod Eurytemora affinis (Poppe) and the influence of salinity

    NASA Astrophysics Data System (ADS)

    Powell, Mark D.; Berry, A. J.

    1990-12-01

    Eurytemora affinis (Poppe) fed on cultured Thalassiosira weissflogii (Grunnow) at rates of 200-34000 cells copepod -1 h -1. Feeding was delayed and diminished in bright light. In dim light, feeding was initially faster in 15 (27000-34000 copepod -1 h -1) than in 10 (23000-25000 copepod -1 h -1) and much faster than in 3 (6000 copepod -1 h -1). After 1-3 h, feeding continued more steadily in 3 (1200-6500 copepod -1 h -1) but slowed drastically in 10 and 15 to 200-5000 copepod -1 h -1). These patterns were maintained when copepods were first acclimated briefly to the test salinities. E. affinis fed at slightly higher rates on sterile latex beads of similar size to T. weissfloggi, fastest in 10 and slowest in 3. While the beads appeared in the guts, they did not appear in the faecal pellets and after 1 h (10, 15) or 3 h (3), their numbers in suspension recovered close to original counts. In contrast, beads infected with a marine bacterium were similarly eaten (at slightly higher rates than the sterile beads), and appeared in the guts and then in the faecal pellets, while numbers in suspension continued to fall or remained low. The contrasts between initial rapid feeding in 10-15 and slower steadier feeding in 3, and between regurgitation of swallowed sterile beads and passage through the gut of bacterially-contaminated beads, have significance for the biology of a copepod living in the upper reaches of an estuary.

  5. Vertical changes in abundance, biomass and community structure of copepods down to 3000 m in the southern Bering Sea

    NASA Astrophysics Data System (ADS)

    Homma, Tomoe; Yamaguchi, Atsushi

    2010-08-01

    Vertical changes in abundance, biomass and community structure of copepods down to 3000 m depth were studied at a single station of the Aleutian Basin of the Bering Sea (53°28'N, 177°00'W, depth 3779 m) on the 14th June 2006. Both abundance and biomass of copepods were greatest near the surface layer and decreased with increase in depth. Abundance and biomass of copepods integrated over 0-3000 m were 1,390,000 inds. m -2 and 5056 mg C m -2, respectively. Copepod carcasses occurred throughout the layer, and the carcass:living specimen ratio was the greatest in the oxygen minimum layer (750-100 m, the ratio was 2.3). A total of 72 calanoid copepod species belonging to 34 genera and 15 families occurred in the 0-3000 m water column (Cyclopoida, Harpacticoida and Poecilostomatoida were not identified to species level). Cluster analysis separated calanoid copepod communities into 5 groups (A-E). Each group was separated by depth, and the depth range of each group was at 0-75 m (A), 75-500 m (B), 500-750 m (C), 750-1500 m (D) and 1500-3000 m (E). Copepods were divided into four types based on the feeding pattern: suspension feeders, suspension feeders in diapause, detritivores and carnivores. In terms of abundance the most dominant group was suspension feeders (mainly Cyclopoida) in the epipelagic zone, and detritivores (mainly Poecilostomatoida) were dominant in the meso- and bathypelagic zones. In terms of biomass, suspension feeders in diapause (calanoid copepods Neocalanus spp. and Eucalanus bungii) were the major component (ca. 10-45%), especially in the 250-3000 m depth. These results are compared with the previous studies in the same region and that down to greater depths in the worldwide oceans.

  6. Copepod grazing during spring blooms: Does Calanus pacificus avoid harmful diatoms?

    NASA Astrophysics Data System (ADS)

    Leising, Andrew W.; Pierson, James J.; Halsband-Lenk, Claudia; Horner, Rita; Postel, James

    2005-11-01

    During late winter and spring of 2002 and 2003, 24, 2-3 day cruises were conducted to Dabob Bay, Washington State, USA, to examine the grazing, egg production, and hatching success rates of adult female Calanus pacificus and Pseudocalanus newmani. The results of the copepod grazing experiments for C. pacificus are discussed here. Each week, copepod grazing incubation experiments from two different depth layers were conducted. Grazing was measured by both changes in chlorophyll concentration and cell counts. In 2002, there was one moderate bloom consisting mainly of Thalassiosira spp. in early February, and a larger bloom in April comprised of two Chaetoceros species and Phaeocystis sp. Similarly, in 2003, there were two blooms, an early one dominated by Thalassiosira spp., and a later one consisting of Chaetoceros spp. and Thalassiosira spp. Clearance rates on individual prey species, as calculated by cell counts, showed that C. pacificus are highly selective in their feeding, and may have much higher clearance rates on individual taxa than rates calculated from bulk chlorophyll disappearance. During weeks of high phytoplankton concentration, the copepods generally ate phytoplankton. However, they often rejected the most abundant phytoplankton species, particularly certain Thalassiosira spp., even though the rejected prey were often of the same genus and similar size to the preferred prey. It is speculated that this avoidance may be related to the possible deleterious effects that certain of these diatom species have on the reproductive success of these copepods. During weeks of medium to low phytoplankton concentration, the copepods selectively ate certain species of phytoplankton, and often had high electivity for microzooplankton. The selection mechanism must consist of active particle rejection most likely based on detection of surface chemical properties, since the diatoms that were selected were of the same genus, nearly the same size, and at lower numerical abundance than those cells that were avoided. The grazing choices made by these copepods may have important consequences for the overall ecosystem function within coastal and estuarine systems through changes in the transfer efficiency of energy to higher trophic levels.

  7. Copepod omnivory in the North Water Polynya (Baffin Bay) during autumn: spatial patterns in lipid composition

    NASA Astrophysics Data System (ADS)

    Stevens, Catherine J.; Deibel, Don; Parrish, Christopher C.

    2004-11-01

    To deduce spatial patterns in copepod lipid composition and feeding strategy (i.e., degree of omnivory) in the North Water Polynya (Baffin Bay), three dominant species were sampled extensively over a broad geographical area (?75-78N; 77-69W). Calanus hyperboreus CV, C. glacialis CV and Metridia longa females were collected in shallow and deep strata at 16 stations during autumn 1999 (August-October). Principal components analysis (PCA) revealed that all species fed omnivorously in the southeastern (SE) region of the polynya. Here, copepods generally had elevated levels of carnivorous (e.g., 18 : 1 (n - 9)), dinoflagellate (e.g., 18 : 4 (n - 3) ; 22 : 6 (n - 3)) and bacterial fatty acid markers (e.g., odd-numbered and/or branched; 18:1(n - 7)). Copepods in the SE contained low proportions of diatom (e.g., 16 : 4 (n - 1) ; 20 : 5 (n - 3)) and phytoplankton (e.g., polyunsaturated fatty acids) markers, relative to animals from northwest stations. Values of the omnivory index 'UC' (i.e., unsaturation coefficient) were also low in SE copepods, which implied reduced phytoplankton ingestion. Spatial patterns in seston fatty acid composition resembled the dietary signatures in that dinoflagellate and bacterial indices were highest in SE waters. Estimates of primary production, particulate organic carbon, carbon to chlorophyll ratios, and abundances of diatoms, dinoflagellates and bacteria, provided further evidence of the importance of the microbial loop at SE stations. Comparable spatial patterns in feeding strategy were observed in both sampling layers, indicating that copepods from the entire water column were feeding on a similar food source. Several interesting species-specific trends also emerged from the PCA. In general, C. hyperboreus fed the most herbivorously, followed by C. glacialis and M. longa. C. glacialis showed a stronger connection to the microbial food web than the other two species, and M. longa fed herbivorously throughout much of the polynya. These latter two findings contradict the conventional wisdom and highlight the need for future work. In particular, the microbial community should be emphasized and characterized in subsequent studies on the feeding ecology of C. glacialis. Although the three species investigated responded quite differently to available prey by adopting specialized feeding strategies, copepod omnivory in the polynya was generally inversely related to the availability of diatoms.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  9. [Biological process of phosphorus turnover in surface water body of Xiamen Harbor. II: Grazing pressure of copepod on phytoplankton].

    PubMed

    Yang, Wei-di; Yang, Qing; Lin, Yuan-shao; Cao, Wen-qing

    2008-12-01

    To understand the roles of copepod in the biogeochemical cycling of phosphorus, gut fluorescence method was applied to examine in situ the grazing rate of copepod on the phytoplankton in Xiamen Time Station (XMTS) in May, August and November 2005 and March 2006. In the meanwhile, the abundance and species composition of copepod were investigated, and the grazing pressure of copepod on the phytoplankton was estimated. The results showed that the annual average grazing rate of copepod was 55.53 microg x m(-3) x d(-1), being the highest (108.98 microg x m(-3) x d(-1)) in autumn and the lowest (7.18 microg x m(-3) x d(-1)) in summer. Based on the estimation from our experimental data, the daily grazing rate of copepod populations on the phytoplankton in Xiamen Harbor was, on annual average, about 1.81% of the phytoplankton's standing stock, with the values in spring, summer, autumn, and winter being 3.22%, 0.06%, 3.52% and 0.46%, respectively. PMID:19288738

  10. Effect of the copepod parasite Nicotho astaci on haemolymph chemistry of the European lobster Homarus gammarus.

    PubMed

    Davies, Charlotte E; Vogan, Claire L; Rowley, Andrew F

    2015-03-01

    The gills of the European lobster Homarus gammarus (L.) are susceptible to parasitization by the copepod Nicotho astaci, the lobster louse. This copepod feeds on haemolymph of the host and can damage the gills, potentially affecting gaseous exchange capabilities. To investigate the host response to the parasite, haemolymph levels of total protein, haemocyanin, glucose and ammonia were quantified in adult lobsters carrying varying parasite loads. Parasite loads correlated positively with total haemolymph protein and haemocyanin concentrations but not with glucose or ammonia concentrations. The data suggest that lobsters with gills damaged by the feeding activities of N. astaci respond by producing higher levels of haemocyanin, which is both a key defence response and may compensate for their decreased respiratory functioning. PMID:25751860

  11. Temperature driven changes in the diet preference of omnivorous copepods: no more meat when it's hot?

    PubMed

    Boersma, Maarten; Mathew, K Avarachen; Niehoff, Barbara; Schoo, Katherina L; Franco-Santos, Rita M; Meunier, Cédric L

    2016-01-01

    Herbivory is more prevalent in the tropics than at higher latitudes. If differences in ambient temperature are the direct cause for this phenomenon, then the same pattern should be visible in a seasonal gradient, as well as in experiments manipulating temperature. Using (15) N stable isotope analyses of natural populations of the copepod Temora longicornis we indeed observed seasonal differences in the trophic level of the copepod and a decrease in trophic level with increasing temperature. In a grazing experiment, with a mixed diet of the cryptophyte Rhodomonas salina and the heterotrophic dinoflagellate Oxyrrhis marina, T. longicornis preferred the cryptophyte at higher temperatures, whereas at lower temperatures it preferred the non-autotrophic prey. We explain these results by the higher relative carbon content of primary producers compared to consumers, in combination with the higher demand for metabolic carbon at higher temperatures. Thus, currently increasing temperatures may cause changes in dietary preferences of many consumers. PMID:26567776

  12. Short term variation in the vertical distribution of copepods off the coast of northern Peru

    SciTech Connect

    Smith, S L; Boyd, C M; Lane, P V.Z.

    1980-04-01

    Vertical profiles of chlorophyll a, oxygen, density and copepods were collected during November 1977 near 9/sup 0/S off Peru. The majority of three groups of copepod, the Oncaeidae, the Oithonidae and small calanoids, remained above the depth (approx. 30m) where concentrations of oxygen became less than 0.5 ml.l/sup -1/ both day and night. Centers of population of all three groups were in or below the pycnocline at all times. In daytime all three groups accumulated at depth, while at night all three groups showed some dispersion throughout the upper 30 m with statistically significant separation in the layers of Oncaeidae and small calanoids. Small calanoids were always higher in the water column than the Oncaeidae at night. The rather small, daily vertical excursions by the Oncaeidae and small calanoids exposed them to mean onshore, poleward flow by day and mean offshore, equatorward flow at night.

  13. Chromatin diminution in the copepod Mesocyclops edax: elimination of both highly repetitive and nonhighly repetitive DNA.

    PubMed

    McKinnon, Christian; Drouin, Guy

    2013-01-01

    Chromatin diminution, a developmentally regulated process of DNA elimination, is found in numerous eukaryotic species. In the copepod Mesocyclops edax, some 90% of its genomic DNA is eliminated during the differentiation of embryonic cells into somatic cells. Previous studies have shown that the eliminated DNA contains highly repetitive sequences. Here, we sequenced DNA fragments from pre- and postdiminution cells to determine whether nonhighly repetitive sequences are also eliminated during the process of chromatin diminution. Comparative analyses of these sequences, as well as the sequences eliminated from the genome of the copepod Cyclops kolensis, show that they all share similar abundances of tandem repeats, dispersed repeats, transposable elements, and various coding and noncoding sequences. This suggests that, in the chromatin diminution observed in M. edax, both highly repetitive and nonhighly repetitive sequences are eliminated and that there is no bias in the type of nonhighly repetitive DNA being eliminated. PMID:23379333

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  15. Acute toxicity, uptake and accumulation kinetics of nickel in an invasive copepod species: Pseudodiaptomus marinus.

    PubMed

    Tlili, Sofiène; Ovaert, Julien; Souissi, Anissa; Ouddane, Baghdad; Souissi, Sami

    2016-02-01

    Pseudodiaptomus marinus is a marine calanoid copepod originating of the Indo-Pacific region, who has successfully colonized new areas and it was recently observed in the European side of the Mediterranean Sea as well as in the North Sea. Actually, many questions were posed about the invasive capacity of this copepod in several non-native ecosystems. In this context, the main aim of this study was to investigate the tolerance and the bioaccumulation of metallic stress in the invasive copepod P. marinus successfully maintained in mass culture at laboratory conditions since 2 years. In order to study the metallic tolerance levels of P. marinus, an emergent trace metal, the nickel, was chosen. First, lethal concentrations determination experiments were done for 24, 48, 72 and 96 h in order to calculated LC50% but also to select a relevant ecological value for the suite of experiments. Then, three types of experiments, using a single concentration of nickel (correspond the 1/3 of 96 h-LC50%) was carried in order to study the toxico-kinetics of nickel in P. marinus. Concerning lethal concentrations, we observed that P. marinus was in the same range of sensitivity compared to other calanoid copepods exposed to nickel in the same standardized experimental conditions. Results showed that the uptake of nickel in P. marinus depends from the pathways of entrance (water of food), but also that Isochrysis galbana, used as a food source, has an important bioaccumulation capacity and a rapid uptake of nickel. PMID:26519805

  16. Unsteady motion: escape jumps in planktonic copepods, their kinematics and energetics

    PubMed Central

    Kiørboe, Thomas; Andersen, Anders; Langlois, Vincent J.; Jakobsen, Hans H.

    2010-01-01

    We describe the kinematics of escape jumps in three species of 0.3–3.0 mm-sized planktonic copepods. We find similar kinematics between species with periodically alternating power strokes and passive coasting and a resulting highly fluctuating escape velocity. By direct numerical simulations, we estimate the force and power output needed to accelerate and overcome drag. Both are very high compared with those of other organisms, as are the escape velocities in comparison to startle velocities of other aquatic animals. Thus, the maximum weight-specific force, which for muscle motors of other animals has been found to be near constant at 57 N (kg muscle)−1, is more than an order of magnitude higher for the escaping copepods. We argue that this is feasible because most copepods have different systems for steady propulsion (feeding appendages) and intensive escapes (swimming legs), with the muscular arrangement of the latter probably adapted for high force production during short-lasting bursts. The resulting escape velocities scale with body length to power 0.65, different from the size-scaling of both similar sized and larger animals moving at constant velocity, but similar to that found for startle velocities in other aquatic organisms. The relative duration of the pauses between power strokes was observed to increase with organism size. We demonstrate that this is an inherent property of swimming by alternating power strokes and pauses. We finally show that the Strouhal number is in the range of peak propulsion efficiency, again suggesting that copepods are optimally designed for rapid escape jumps. PMID:20462876

  17. Growth and production of the copepod community in the southern area of the Humboldt Current System

    NASA Astrophysics Data System (ADS)

    Escribano, R.; Bustos-Ros, E.; Hidalgo, P.; Morales, C. E.

    2015-02-01

    Zooplankton production is a critical issue for understanding marine ecosystem structure and dynamics, however, its time-space variations are mostly unknown in most systems. In this study, estimates of copepod growth and production (CP) in the coastal upwelling and coastal transition zones off central-southern Chile (∼35-37 S) were obtained from annual cycles during a 3 year time series (2004, 2005, and 2006) at a fixed shelf station and from spring-summer surveys during the same years. C-specific growth rates (g) varied extensively among species and under variable environmental conditions; however, g values were not correlated to either near surface temperature or copepod size. Copepod biomass (CB) and CP were higher within the coastal upwelling zone (<50 km) and both decreased substantially from 2004 to 2006. Annual CP ranged between 24 and 52 g C m-2 year-1 with a~mean annual P/B ratio of 2.7. We estimated that CP could consume up to 60% of the annual primary production (PP) in the upwelling zone but most of the time is around 8%. Interannual changes in CB and CP values were associated with changes in the copepod community structure, the dominance of large-sized forms replaced by small-sized species from 2004 to 2006. This change was accompanied by more persistent and time extended upwelling during the same seasonal period. Extended upwelling may have caused large losses of CB from the upwelling zone due to an increase in offshore advection of coastal plankton. On a larger scale, these results suggest that climate-related impacts of increasing wind-driven upwelling in coastal upwelling systems may generate a negative trend in zooplankton biomass.

  18. Copepod grazing during spring blooms: Can Pseudocalanus newmani induce trophic cascades?

    NASA Astrophysics Data System (ADS)

    Leising, Andrew W.; Pierson, James J.; Halsband-Lenk, Claudia; Horner, Rita; Postel, James

    2005-11-01

    During late winter and spring of 2002 and 2003, 24 two- to three-day cruises were conducted to Dabob Bay, Washington State, USA, to examine the grazing, egg production, and hatching success rates of adult female Calanus pacificus and Pseudocalanus newmani. Here, we discuss the results of our grazing experiments for P. newmani. Each week, we conducted traditional microzooplankton dilution experiments and “copepod dilution” experiments, each from two different layers. Grazing was measured by changes in chlorophyll concentration and direct cell counts. Clearance rates on individual prey species, as calculated by cell counts, showed that Pseudocalanus are highly selective in their feeding, and may have much higher grazing rates on individual taxa than calculated from bulk chlorophyll disappearance. The grazing rates of the copepods, however, are typically an order of magnitude lower than the grazing rates of the microzooplankton community, or the growth rates of the phytoplankton. P. newmani ingested diatoms, but, at certain times fed preferentially on microzooplankton, such as ciliates, tintinnids, and larger dinoflagellates. Removal of the microzooplankton may have released the other phytoplankton species from grazing pressure, allowing those species’ abundance to increase, which was measured as an apparent “negative” grazing on those phytoplankton species. The net result of grazing on some phytoplankton species, while simultaneously releasing others from grazing pressure resulted in bulk chlorophyll-derived estimates of grazing which were essentially zero or slightly negative; thus bulk chlorophyll disappearance is a poor indicator of copepod grazing. Whether copepods can significantly release phytoplankton from the grazing pressure by microzooplankton in situ, thus causing a trophic cascade, remains to be verified, but is suggested by our study.

  19. Rates of ingestion and their variability between individual calanoid copepods: Direct observations

    SciTech Connect

    Paffenhoefer, G.A.; Lewis, K.D.; Bundy, M.H. |; Metz, C.

    1995-12-01

    The goals of this study were to determine rates of ingestion and fecal pellet release, and their variability, for individual planktonic copepods over extended periods of time (>20 min). Ingestions and rejections of individual cells of the diatom Thalassiosira eccentrica by a adult females of the calanoid Paracalanus aculeatus were directly quantified by observing individual copepods continuously at cell concentrations ranging from 0.1 to 1.2 mm{sup 3} l{sup {minus}1}. Average ingestion rates increased with increasing food concentration, but were not significantly different between 0.3 and 1.0 mm{sup 3} l{sup {minus}1} (9.8 and 32.7 {mu}g Cl{sup {minus}1}) of T.eccentrica. Rates of cell rejections were low and similar at 0.1 and 0.3. but were significantly higher at 1.0 mm{sup 3} l{sup {minus}1}. The coefficients of variation for average ingestion rates of individual copepods hardly differed between food concentrations, ranging from 17 to 22%, and were close to those for average fecal pellet release intervals which ranged from 15 to 21%. A comparison between individuals at each food concentration found no significant differences at 1.0; at 0.1 and 0.3 mm{sup 3} l{sup {minus}1}, respectively, ingestion rates of four out of five females did not differ significantly from each other. Average intervals between fecal pellet releases were similar at 0.3 and 1.0 mm{sup 3} l{sup {minus}1}. Fecal pellet release intervals between individuals were significantly different at each food concentration; these significant differences were attributed to rather narrow ranges of pellet release intervals of each individual female. Potential sources/causes of variability in the sizes and rates of copepods in the ocean are evaluated.

  20. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    NASA Astrophysics Data System (ADS)

    Kiko, R.; Hauss, H.; Buchholz, F.; Melzner, F.

    2015-10-01

    Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2 and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply considerably fuels bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a downregulation of ammonium excretion. Here we show that exposure to OMZ conditions can result in strong depression of respiration and ammonium excretion in calanoid copepods and euphausiids from the Eastern Tropical North Atlantic and the Eastern Tropical South Pacific. These physiological responses need to be taken into account when estimating DVM-mediated fluxes of carbon and nitrogen into OMZs.

  1. Acute and chronic temperature stress on copepod individuals and populations. Final report, November 1977-February 1983

    SciTech Connect

    Bradley, B.P.

    1983-10-01

    Temperature variation resulting from thermal discharges of two power plants affected temperature tolerances and densities of two copepod species, Eurytemora affinis and Acartia tonsa. Temperature tolerances were increased genetically (next generation) provided either ambient temperature or delta T was sufficiently high. Densities also varied with temperature but not always systematically. Other criteria used to assess the environmental influence of power plant were egg production and potentials for physiological and genetic adaptation.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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 μm) and medium copepods (MC: body size ranging from 500 to 1000 μm), 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 μm), 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.

  3. Identification and molecular characterization of nitric oxide synthase (NOS) gene in the intertidal copepod Tigriopus japonicus.

    PubMed

    Jeong, Chang-Bum; Kang, Hye-Min; Seo, Jung Soo; Park, Heum Gi; Rhee, Jae-Sung; Lee, Jae-Seong

    2016-02-10

    In copepods, no information has been reported on the structure or molecular characterization of the nitric oxide synthase (NOS) gene. In the intertidal copepod Tigriopus japonicus, we identified a NOS gene that is involved in immune responses of vertebrates and invertebrates. In silico analyses revealed that nitric oxide (NO) synthase domains, such as the oxygenase and reductase domains, are highly conserved in the T. japonicus NOS gene. The T. japonicus NOS gene was highly transcribed in the nauplii stages, implying that it plays a role in protecting the host during the early developmental stages. To examine the involvement of the T. japonicus NOS gene in the innate immune response, the copepods were exposed to lipopolysaccharide (LPS) and two Vibrio sp. After exposure to different concentrations of LPS and Vibrio sp., T. japonicus NOS transcription was significantly increased over time in a dose-dependent manner, and the NO/nitrite concentration increased as well. Taken together, our findings suggest that T. japonicus NOS transcription is induced in response to an immune challenge as part of the conserved innate immunity. PMID:26611530

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

    PubMed Central

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

    2013-01-01

    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

  5. Reproduction dynamics in copepods following exposure to chemically and mechanically dispersed crude oil.

    PubMed

    Hansen, Bjørn Henrik; Salaberria, Iurgi; Olsen, Anders J; Read, Kari Ella; Øverjordet, Ida Beathe; Hammer, Karen M; Altin, Dag; Nordtug, Trond

    2015-03-17

    Conflicting reports on the contribution of chemical dispersants on crude oil dispersion toxicity have been published. This can partly be ascribed to the influence of dispersants on the physical properties of the oil in different experimental conditions. In the present study the potential contribution of dispersants to the reproductive effects of dispersed crude oil in the marine copepod Calanus finmarchicus (Gunnerus) was isolated by keeping the oil concentrations and oil droplet size distributions comparable between parallel chemically dispersed (CD, dispersant:oil ratio 1:25) and mechanically dispersed oil (MD, no dispersant) exposures. Female copepods were exposed for 96 h to CD or MD in oil concentration range of 0.2-5.5 mg·L(-1) (THC, C5-C36) after which they were subjected to a 25-day recovery period where production of eggs and nauplii were compared between treatments. The two highest concentrations, both in the upper range of dispersed oil concentrations reported during spills, caused a lower initial production of eggs/nauplii for both MD and CD exposures. However, copepods exposed to mechanically dispersed oil exhibited compensatory reproduction during the last 10 days of the recovery period, reaching control level of cumulative egg and nauplii production whereas females exposed to a mixture of oil and dispersant did not. PMID:25658869

  6. Size-dependent effects of micro polystyrene particles in the marine copepod Tigriopus japonicus.

    PubMed

    Lee, Kyun-Woo; Shim, Won Joon; Kwon, Oh Youn; Kang, Jung-Hoon

    2013-10-01

    We investigated the effects of three sizes of polystyrene (PS) microbeads (0.05, 0.5, and 6-?m diameter) on the survival, development, and fecundity of the copepod Tigriopus japonicus using acute and chronic toxicity tests. T. japonicus ingested and egested all three sizes of PS beads used and exhibited no selective feeding when phytoplankton were added. The copepods (nauplius and adult females) survived all sizes of PS beads and the various concentrations tested in the acute toxicity test for 96 h. In the two-generation chronic toxicity test, 0.05-?m PS beads at a concentration greater than 12.5 ?g/mL caused the mortality of nauplii and copepodites in the F0 generation and even triggered mortality at a concentration of 1.25 ?g/mL in the next generation. In the 0.5-?m PS bead treatment, despite there being no significant effect on the F0 generation, the highest concentration (25 ?g/mL) induced a significant decrease in survival compared with the control population in the F1 generation. The 6-?m PS beads did not affect the survival of T. japonicus over two generations. The 0.5- and 6-?m PS beads caused a significant decrease in fecundity at all concentrations. These results suggest that microplastics such as micro- or nanosized PS beads may have negative impacts on marine copepods. PMID:23988225

  7. Copepod distribution and production in a Mid-Atlantic Ridge archipelago.

    PubMed

    Melo, Pedro A M C; Melo Jnior, Mauro DE; Macdo, Silvio J DE; Araujo, Moacyr; Neumann-Leito, Sigrid

    2014-11-11

    The Saint Peter and Saint Paul Archipelago (SPSPA) are located close to the Equator in the Atlantic Ocean. The aim of this study was to assess the spatial variations in the copepod community abundance, and the biomass and production patterns of the three most abundant calanoid species in the SPSPA. Plankton samples were collected with a 300 m mesh size net along four transects (north, east, south and west of the SPSPA), with four stations plotted in each transect. All transects exhibited a tendency toward a decrease in copepod density with increasing distance from the SPSPA, statistically proved in the North. Density varied from 3.33 to 182.18 ind.m-3, and differences were also found between the first perimeter (first circular distance band) and the others. The total biomass varied from 15.25 to 524.50 10-3 mg C m-3 and production from 1.19 to 22.04 10-3 mg C m-3d-1. The biomass and production of Undinula vulgaris (Dana, 1849), Acrocalanus longicornis Giesbrecht, 1888 and Calocalanus pavo (Dana, 1849) showed differences between some transects. A trend of declining biodiversity and production with increasing distance from archipelago was observed, suggesting that even small features like the SPSPA can affect the copepod community in tropical oligotrophic oceanic areas. PMID:25387389

  8. Copepod distribution and production in a Mid-Atlantic Ridge archipelago.

    PubMed

    Melo, Pedro A M C; De Melo Jnior, Mauro; De Macdo, Silvio J; Araujo, Moacyr; Neumann-Leito, Sigrid

    2014-12-01

    The Saint Peter and Saint Paul Archipelago (SPSPA) are located close to the Equator in the Atlantic Ocean. The aim of this study was to assess the spatial variations in the copepod community abundance, and the biomass and production patterns of the three most abundant calanoid species in the SPSPA. Plankton samples were collected with a 300 m mesh size net along four transects (north, east, south and west of the SPSPA), with four stations plotted in each transect. All transects exhibited a tendency toward a decrease in copepod density with increasing distance from the SPSPA, statistically proved in the North. Density varied from 3.33 to 182.18 ind.m-3, and differences were also found between the first perimeter (first circular distance band) and the others. The total biomass varied from 15.25 to 524.50 10-3 mg C m-3 and production from 1.19 to 22.04 10-3 mg C m-3d-1. The biomass and production of Undinula vulgaris (Dana, 1849), Acrocalanus longicornis Giesbrecht, 1888 and Calocalanus pavo (Dana, 1849) showed differences between some transects. A trend of declining biodiversity and production with increasing distance from archipelago was observed, suggesting that even small features like the SPSPA can affect the copepod community in tropical oligotrophic oceanic areas. PMID:25590711

  9. Lethal and sublethal effects of the sediment-associated PCB Aroclor 1254 on a meiobenthic copepod

    SciTech Connect

    DiPinto, L.M.; Coull, B.C.; Chandler, G.T. . Dept. of Environmental Health Sciences, Marine Science Program, and Belle W. Baruch Inst. for Marine Biology and Coastal Research)

    1993-10-01

    Acute toxicity tests were performed on field-collected copepods (Microarthridion littorale) using the sediment-associated polychlorinated biphenyl (PCB) Aroclor 1254 (i.e., PCB concentrations in bulk sediments in the bound and/or unbound states). Three replicates of 50 adult copepods were exposed to five levels of PCB-contaminated sediments for 96 h and compared to untreated controls and solvent controls. LC50 concentrations were nearly twice as high for females as for males. To determine the effects of the PCB on reproductive output of the copepods, copulating pairs of Microarthridion littorale were allowed to reproduce in concentrations of Aroclor 1254-contaminated sediments below LC50 values. Two experimental trials with 10 and 15 replicates, each with one pair of Microarthridion littorale in copulus, were conducted for 12 d, the normal time needed for females to produce one set of nauplii and carry a second clutch of eggs. In both experiments, a significant decrease in number of nauplii was found with Aroclor contamination. Although NOECs were not determined, high concentrations of the sediment-associated Aroclor NOECs were required to affect mortality significantly, whereas lower levels impaired reproduction.

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

    SciTech Connect

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

    1999-01-01

    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.

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

    PubMed

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

    2011-05-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    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.

  13. Fitness consequences for copepods feeding on a red tide dinoflagellate: deciphering the effects of nutritional value, toxicity, and feeding behavior.

    PubMed

    Prince, Emily K; Lettieri, Liliana; McCurdy, Katherine J; Kubanek, Julia

    2006-03-01

    Phytoplankton exhibit a diversity of morphologies, nutritional values, and potential chemical defenses that could affect the feeding and fitness of zooplankton consumers. However, how phytoplankton traits shape plant-herbivore interactions in the marine plankton is not as well understood as for terrestrial or marine macrophytes and their grazers. The occurrence of blooms of marine dinoflagellates such as Karenia brevis suggests that, for uncertain reasons, grazers are unable to capitalize on, or control, this phytoplankton growth-making these systems appealing for testing mechanisms of grazing deterrence. Using the sympatric copepod Acartia tonsa, we conducted a mixed diet feeding experiment to test whether K. brevis is beneficial, toxic, nutritionally inadequate, or behaviorally rejected as food relative to the palatable and nutritionally adequate phytoplankter Rhodomonas lens. On diets rich in K. brevis, copepods experienced decreased survivorship and decreased egg production per female, but the percentage of eggs that hatched was unaffected. Although copepods showed a 6-17% preference for R. lens over K. brevis on some mixed diets, overall high ingestion rates eliminated the possibility that reduced copepod fitness was caused by copepods avoiding K. brevis, leaving nutritional inadequacy and toxicity as remaining hypotheses. Because egg production was dependent on the amount of R. lens consumed regardless of the amount of K. brevis eaten, there was no evidence that fitness costs were caused by K. brevis toxicity. Copepods limited to K. brevis ate 480% as much as those fed only R. lens, suggesting that copepods attempted to compensate for low food quality with increased quantity ingested. Our results indicate that K. brevis is a poor food for A. tonsa, probably due to nutritional inadequacy rather than toxicity, which could affect bloom dynamics in the Gulf of Mexico where these species co-occur. PMID:16261377

  14. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae - can we identify the underlying factors?

    PubMed

    Karlsen, Ørjan; van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F; Kjørsvik, Elin; Hamre, Kristin

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks. PMID:26038712

  15. Acute and chronic toxicities of zinc pyrithione alone and in combination with copper to the marine copepod Tigriopus japonicus.

    PubMed

    Bao, Vivien W W; Lui, Gilbert C S; Leung, Kenneth M Y

    2014-12-01

    Zinc pyrithione (ZnPT) is a widely used booster biocide in combination with copper (Cu) in antifouling paints as a substitute for tributyltin. The co-occurrence of ZnPT and Cu in coastal marine environments is therefore very common, and may pose a higher risk to marine organisms if they can result in synergistic toxicity. This study comprehensively investigated the combined toxicity of ZnPT and Cu, on the marine copepod Tigriopus japonicus, for the first time, based on both 96-h acute toxicity tests using adult copepods and chronic full-life cycle tests (21 d) using nauplii <24-h old. As ZnPT has been reported to be easily trans-chelated to copper pyrithione (CuPT) in the presence of Cu, the acute toxicities of CuPT alone and in combination with Cu on adult copepods were also assessed. Our results showed that ZnPT and Cu exhibited a strong synergistic toxic effect on the copepod in both acute and chronic tests. During the acute test, the mortalities of adult copepods increased dramatically even with an addition of Cu at concentrations as low as 1-2 ?g/L compared with those exposed to ZnPT alone. Severe chronic toxicities were further observed in the copepods exposed to ZnPT-Cu mixtures, including a significant increase of naupliar mortality, postponing of development from naupliar to copepodid and from copepodid to adult stage, and a significant decrease of intrinsic population growth when compared with those of copepods exposed to ZnPT or Cu alone. Such synergistic effects might be partly attributable to the formation of CuPT by the trans-chelation of ZnPT and Cu, because CuPT was found to be more toxic than ZnPT based on the acute toxicity results. Mixtures of CuPT and Cu also led to synergistic toxic effects to the copepod, in particular at high Cu concentrations. A novel non-parametric response surface model was applied and it proved to be a powerful method for analysing and predicting the acute binary mixture toxicities of the booster biocides (i.e., ZnPT and CuPT) and Cu on the copepod. To better protect precious marine resources, it is necessary to revise and tighten existing water quality criteria for biocides, such as ZnPT and CuPT, to account for their synergistic effects with Cu at environmentally realistic levels. PMID:25456222

  16. Control of Diapause by Acidic pH and Ammonium Accumulation in the Hemolymph of Antarctic Copepods

    PubMed Central

    Schrnder, Sabine; Schnack-Schiel, Sigrid B.; Auel, Holger; Sartoris, Franz Josef

    2013-01-01

    Life-cycles of polar herbivorous copepods are characterised by seasonal/ontogenetic vertical migrations and diapause to survive periods of food shortage during the long winter season. However, the triggers of vertical migration and diapause are still far from being understood. In this study, we test the hypothesis that acidic pH and the accumulation of ammonium (NH4+) in the hemolymph contribute to the control of diapause in certain Antarctic copepod species. In a recent study, it was already hypothesized that the replacement of heavy ions by ammonium is necessary for diapausing copepods to achieve neutral buoyancy at overwintering depth. The current article extends the hypothesis of ammonium-aided buoyancy by highlighting recent findings of low pH values in the hemolymph of diapausing copepods with elevated ammonium concentrations. Since ammonia (NH3) is toxic to most organisms, a low hemolymph pH is required to maintain ammonium in the less toxic ionized form (NH4+). Recognizing that low pH values are a relevant factor reducing metabolic rate in other marine invertebrates, the low pH values found in overwintering copepods might not only be a precondition for ammonium accumulation, but in addition, it may insure metabolic depression throughout diapause. PMID:24143238

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

    PubMed Central

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

    2013-01-01

    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

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

    PubMed Central

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

    2014-01-01

    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

  19. Intraspecific differences in lipid content of calanoid copepods across fine-scale depth ranges within the photic layer.

    PubMed

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

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Gowing, Marcia M.; Wishner, Karen F.

    1986-07-01

    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.

  1. Vertical distribution of copepods and the utilization of the chlorophyll a-rich layer within Concepcion Bay, Chile

    NASA Astrophysics Data System (ADS)

    Castro, Leonardo R.; Bernal, Patricio A.; Gonzalez, Humberto E.

    1991-03-01

    The potential factors contributing to the development of vertical distribution patterns of two copepod species, Calanus chilensis and Calanoides patagoniensis, were studied in Concepcion Bay, Chile, during three 24-h cruises in late winter, mid-spring 1984 and early winter 1986. Results show that both species tend to aggregate at the depth of maximum chlorophyll a in the water column and that neither minimum oxygen concentrations (<1 ml O 2l -1) nor strong thermoclines play a determinant role in the depth of maximum copepod aggregation. Gut contents (chlorophyll a and phaeopigments) in copepods revealed that the peak in feeding activity occurred during the night for both C. chilensis in June and for C. patagoniensis in November. The C. chilensis and C. patagoniensis populations consumed about 70% and 50% of their total daily ingestion in the chlorophyll a-rich layers in June and November, respectively. In spite of the environmental and population abundance differences between June and November, both copepod populations presented similar values of food consumption: the C. chilensis population ingested up to 8·47 mg C m 2 day -1 in June while the C. patagoniensis population consumed 6·81 mg C m -2 day -1 in November. The daily ingestion carried out by each copepod species would represent less than 1% of the total daily primary productivity in both months. Our results suggest that a great amount of phytoplankton biomass is not directly utilized by zooplankton in Concepcion Bay.

  2. Ocean acidification impact on copepod swimming and mating behavior: consequences for population dynamics

    NASA Astrophysics Data System (ADS)

    Seuront, L.

    2010-12-01

    There is now ample evidence that ocean acidification caused by the uptake of additional carbon dioxide from the atmosphere at the ocean surface will severely impact on marine ecosystem structure and function. To date, most research effort has focused on the impact of ocean acidification on calcifying marine organisms. These include the dissolution of calcifying plankton, reduced growth and shell thickness in gastropods and echinoderms and declining growth of reef-building corals. The effects of increasing the partial pressure in carbon dioxide and decreasing carbonate concentrations on various aspects of phytoplankton biology and ecology have received some attention. It has also recently been shown that the ability of fish larvae to discriminate between the olfactory cues of different habitat types at settlement and to detect predator olfactory cues are impaired at the level of ocean acidification predicted to occur around 2100 on a business-as-usual scenario of CO2 emissions. Average ocean pH has decreased by 0.1 units since the pre-industrial times, and it is predicted to decline another 0.3-0.4 units by 2100, which nearly corresponds to a doubling PCO2. In addition, some locations are expected to exhibit an even greater than predicted rate of decline. In this context, understanding the direct and indirect links between ocean acidification and the mortality of marine species is critical, especially for minute planktonic organisms such as copepods at the base of the ocean food chains. In this context, this work tested if ocean acidification could affect copepod swimming behavior, and subsequently affect, and ultimately disrupt, the ability of male copepods to detect and follow the pheromone plume produced by conspecific females. To ensure the generality and the ecological relevance of the present work, the species used for the experimentation are two of the most common zooplankton species found in estuarine and coastal waters of the Northern Hemisphere, the calanoid copepods Eurytemora affinis and Temora longicornis. Behavioral and mating experiments were conducted under conditions of control seawater (pH = 8.1) and conditions of ocean pH expected to occur circa 2100 (i.e. pH = 7.8 to 7.6) because of present and future CO2 emissions under the SRES A2 scenario. Our results indicate that ocean acidification modifies E. affinis and T. longicornis swimming and mating behaviors, and mating success. Specifically, ocean acidification significantly (i) modifies the stochastic properties of successive displacements, leading to decrease mate encounter rates when copepods cannot rely on female pheromone plumes (i.e. under turbulent conditions) and (ii) decreases the ability of males to detect females pheromone trails, to accurately follow trails and to successfully track a female. This led to a significant decrease in contact and capture rates from control to acidified seawater. These results indicate that ocean acification decreases the ability of male copepods to detect, track and capture a female, hence suggest an overall impact on population fitness and dynamics.

  3. Distribution and Ecophysiology of Calanoid Copepods in Relation to the Oxygen Minimum Zone in the Eastern Tropical Atlantic

    PubMed Central

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

    2013-01-01

    Oxygen minimum zones (OMZs) affect distribution patterns, community structure and metabolic processes of marine organisms. Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology. For this study, calanoid copepods were sampled from different depths (01800 m) at eight stations in the eastern tropical Atlantic (347?N to 18S) during three expeditions in 2010 and 2011. Their horizontal and vertical distribution was determined and related to the extent and intensity of the OMZ, which increased from north to south with minimum O2 concentrations (12.7 mol kg?1) in the southern Angola Gyre. Calanoid copepod abundance was highest in the northeastern Angola Basin and decreased towards equatorial regions as well as with increasing depth. Maximum copepod biodiversity was observed in the deep waters of the central Angola Basin. Respiration rates and enzyme activities were measured to reveal species-specific physiological adaptations. Enzyme activities of the electron transport system (ETS) and lactate dehydrogenase (LDH) served as proxies for aerobic and anaerobic metabolic activity, respectively. Mass-specific respiration rates and ETS activities decreased with depth of occurrence, consistent with vertical changes in copepod body mass and ambient temperature. Copepods of the families Eucalanidae and Metridinidae dominated within the OMZ. Several of these species showed adaptive characteristics such as lower metabolic rates, additional anaerobic activity and diel vertical migration that enable them to successfully inhabit hypoxic zones. PMID:24223716

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

    PubMed

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

    2014-03-15

    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

  5. Temperature Affects the Use of Storage Fatty Acids as Energy Source in a Benthic Copepod (Platychelipus littoralis, Harpacticoida).

    PubMed

    Werbrouck, Eva; Van Gansbeke, Dirk; Vanreusel, Ann; De Troch, Marleen

    2016-01-01

    The utilization of storage lipids and their associated fatty acids (FA) is an important means for organisms to cope with periods of food shortage, however, little is known about the dynamics and FA mobilization in benthic copepods (order Harpacticoida). Furthermore, lipid depletion and FA mobilization may depend on the ambient temperature. Therefore, we subjected the temperate copepod Platychelipus littoralis to several intervals (3, 6 and 14 days) of food deprivation, under two temperatures in the range of the normal habitat temperature (4, 15°C) and under an elevated temperature (24°C), and studied the changes in FA composition of storage and membrane lipids. Although bulk depletion of storage FA occurred after a few days of food deprivation under 4°C and 15°C, copepod survival remained high during the experiment, suggesting the catabolization of other energy sources. Ambient temperature affected both the degree of FA depletion and the FA mobilization. In particular, storage FA were more exhausted and FA mobilization was more selective under 15°C compared with 4°C. In contrast, depletion of storage FA was limited under an elevated temperature, potentially due to a switch to partial anaerobiosis. Food deprivation induced selective DHA retention in the copepod's membrane, under all temperatures. However, prolonged exposure to heat and nutritional stress eventually depleted DHA in the membranes, and potentially induced high copepod mortality. Storage lipids clearly played an important role in the short-term response of the copepod P. littoralis to food deprivation. However, under elevated temperature, the use of storage FA as an energy source is compromised. PMID:26986852

  6. Seasonal change in body length of important small copepods and relationship with environmental factors in Jiaozhou Bay, China

    NASA Astrophysics Data System (ADS)

    Sun, Xiaohong; Sun, Song; Li, Chaolun; Wang, Minxiao

    2012-05-01

    Differences among species in prosome length and in species' response to environmental factors do exist. Therefore, it is useful to examine prosome length for different copepod species in variable environments. Seasonal variations in prosome length of four small copepods and their copepodite stages in the Jiaozhou Bay were compared and the relative influence of temperature, salinity, and chlorophyll concentration were examined. Two peaks were found in the mean prosome length of Paracalanus parvus (in early winter and May). For Acartia bifilosa, the maximum values of all copepodites occurred mainly from February to April, and decreased to the bottom in July. Prosome length of Acartia pacifica peaked when it first appeared in June, then reached to the minimum in July. Parvocalanus crassirostris only appeared from late summer to autumn and the mean prosome length showed no clear changes. Correlations of adult prosome length with environmental factors were evaluated. For the four species, temperature was negatively correlated to prosome length except for P. crassirostris. But the different species varied markedly in their responds to temperature. A. bifilosa showed a more definite trend of size variation with temperature than P. parvus and A. pacifica. Correlations of prosome length with salinity were significantly positive for almost all the small copepods. The relationship between chlorophyll concentration and prosome length was complicated for these copepods, but for P. parvus, chlorophyll concentration was also an important affecting factor. Furthermore, investigation needs to be done on food quality for some copepod. These results are essential to estimate the biomass and the production, and to understand these small copepods' population dynamics in this human-affected bay.

  7. Distribution and ecophysiology of calanoid copepods in relation to the oxygen minimum zone in the eastern tropical atlantic.

    PubMed

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

    2013-01-01

    Oxygen minimum zones (OMZs) affect distribution patterns, community structure and metabolic processes of marine organisms. Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology. For this study, calanoid copepods were sampled from different depths (0-1800 m) at eight stations in the eastern tropical Atlantic (3 47'N to 18 S) during three expeditions in 2010 and 2011. Their horizontal and vertical distribution was determined and related to the extent and intensity of the OMZ, which increased from north to south with minimum O2 concentrations (12.7 mol kg(-1)) in the southern Angola Gyre. Calanoid copepod abundance was highest in the northeastern Angola Basin and decreased towards equatorial regions as well as with increasing depth. Maximum copepod biodiversity was observed in the deep waters of the central Angola Basin. Respiration rates and enzyme activities were measured to reveal species-specific physiological adaptations. Enzyme activities of the electron transport system (ETS) and lactate dehydrogenase (LDH) served as proxies for aerobic and anaerobic metabolic activity, respectively. Mass-specific respiration rates and ETS activities decreased with depth of occurrence, consistent with vertical changes in copepod body mass and ambient temperature. Copepods of the families Eucalanidae and Metridinidae dominated within the OMZ. Several of these species showed adaptive characteristics such as lower metabolic rates, additional anaerobic activity and diel vertical migration that enable them to successfully inhabit hypoxic zones. PMID:24223716

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

    PubMed Central

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

    2013-01-01

    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

  9. From Local Adaptation to Ecological Speciation in Copepod Populations from Neighboring Lakes

    PubMed Central

    Barrera-Moreno, Omar Alfredo; Ciros-Pérez, Jorge; Ortega-Mayagoitia, Elizabeth; Alcántara-Rodríguez, José Arturo; Piedra-Ibarra, Elías

    2015-01-01

    Continental copepods have been derived from several independent invasive events from the sea, but the subsequent evolutionary processes that account for the current diversity in lacustrine environments are virtually unknown. Salinity is highly variable among lakes and constitutes a source of divergent selection driving potential reproductive isolation. We studied four populations of the calanoid copepod Leptodiaptomus cf. sicilis inhabiting four neighboring lakes with a common history (since the Late Pleistocene) located in the Oriental Basin, Mexico; one lake is shallow and varies in salinity periodically (1.4–10 g L-1), while three are deep and permanent, with constant salinity (0.5, 1.1 and 6.5 g L-1, respectively). We hypothesized that (1) these populations belong to a different species than L. sicilis sensu stricto and (2) are experiencing ecologically based divergence due to salinity differences. We assessed morphological and molecular (mtDNA) COI variation, as well as fitness differences and tests of reproductive isolation. Although relationships of the Mexican populations with L. sicilis s.s. could not be elucidated, we identified a clear pattern of divergent selection driven by salinity conditions. The four populations can still be considered a single biological species (sexual recognition and hybridization are still possible in laboratory conditions), but they have diverged into at least three different phenotypes: two locally adapted, specialized in the lakes of constant salinity (saline vs. freshwater), and an intermediate generalist phenotype inhabiting the temporary lake with fluctuating salinity. The specialized phenotypes are poorly suited as migrants, so prezygotic isolation due to immigrant inviability is highly probable. This implication was supported by molecular evidence that showed restricted gene flow, persistence of founder events, and a pattern of allopatric fragmentation. This study showed how ecologically based divergent selection may explain diversification patterns in lacustrine copepods. PMID:25915059

  10. Zooplankton community structure during a transition from dry to wet state in a shallow, subtropical estuarine lake

    NASA Astrophysics Data System (ADS)

    Carrasco, Nicola K.; Perissinotto, Renzo

    2015-12-01

    Lake St Lucia is among the most important shallow ecosystems globally and Africa's largest estuarine lake. It has long been regarded as a resilient system, oscillating through periods of hypersalinity and freshwater conditions, depending on the prevailing climate. The alteration of the system's catchment involving the diversion of the Mfolozi River away from Lake St Lucia, however, challenged the resilience of the system, particularly during the most recent drought (2002-2011), sacrificing much of its biodiversity. This study reports on the transition of the St Lucia zooplankton community from a dry hypersaline state to a new wet phase. Sampling was undertaken during routine quarterly surveys at five representative stations along the lake system from February 2011 to November 2013. A total of 54 taxa were recorded during the study period. The zooplankton community was numerically dominated by the calanoid copepods Acartiella natalensis and Pseudodiaptomus stuhlmanni and the cyclopoid copepod Oithona brevicornis. While the mysid Mesopodopsis africana was still present in the system during the wet phase, it was not found in the swarming densities that were recorded during the previous dry phase, possibly due to increased predation pressure, competition with other taxa and or the reconnection with the Mfolozi River via a beach spillway. The increase in zooplankton species richness recorded during the present study shows that the system has undergone a transition to wet state, with the zooplankton community structure reflecting that recorded during the past. It is likely, though, that only a full restoration of natural mouth functioning will result in further diversity increases.

  11. Effects of four synthetic musks on the life cycle of the harpacticoid copepod Nitocra spinipes.

    PubMed

    Breitholtz, Magnus; Wollenberger, Leah; Dinan, Laurence

    2003-04-10

    A full life-cycle (copepod Nitocra spinipes was used to study the effects of one nitro musk (musk ketone) as well as three polycyclic musks (Tonalide, Celestolide and Galaxolide). A subchronic individual life-table endpoint, the larval development rate, was recorded after 7-8 days exposure of juveniles and was significantly decreased in copepods exposed to sublethal concentrations of musk ketone, Celestolide and Galaxolide. However, none of the Tonalide concentrations had any effect on larval development. The lowest Galaxolide concentration (0.02 mg/l), which affected juvenile development, was about 100 times below the adult 96-h-LC(50)-value of 1.9 mg/l (95% confidence interval: 1.4-2.7 mg/l). However, none of the four musks had any agonistic or antagonistic activity in the ecdysteroid-sensitive Drosophila melanogaster B(II)-cell line. This indicates that the decrease in larval development rate was due to pharmacological effects rather than steroid receptor-mediated endocrine disruption. 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. The second highest musk ketone concentration (0.1 mg/l) was the only treatment, which significantly affected r(m) (***P<0.001). At the highest musk ketone (0.3 mg/l) and Celestolide (0.3 mg/l) concentrations, all copepods were dead at the end of the exposures. This shows that a sensitive individual life-table endpoint is protective over the population-level endpoint r(m). Though we think that it is necessary to obtain population-level endpoints from standardised toxicity test, for ecologically successful risk characterisation of synthetic musks as well as other chemicals. The results from the present study show that it is possible to obtain population-level data from the full life-cycle test with N. spinipes. However, there seems to be little risk that synthetic musks are harmful to copepods at present environmental concentrations. PMID:12657486

  12. Eight new species of ascidicolous copepods from the eastern coast of Korea (Crustacea, Copepoda, Cyclopoida)

    NASA Astrophysics Data System (ADS)

    Kim, Il-Hoi; Moon, Seong Yong

    2011-03-01

    Eight new species of copepods associated with shallow-water ascidians are described from the eastern coast of Korea. They are Ascidicola secundus n. sp. from a Pyura sp., Enteropsis nudus n. sp. from Pyura sacciformis (Drasche), Mycophilus capillatus n. sp. from a compound ascidian, Bonnierilla yangpoensis n. sp. from Phallusia cf. nigra Savigny, Janstockia truncata n. sp. from Chelyosoma siboja Oka, Pholeterides pilosa n. sp. from a compound ascidian, Pachypygus spinosus n. sp. from a solitary ascidian, and Paranotodelphys unguifer n. sp. from Ascidia samea Oka.

  13. Fully defined saltwater medium for cultivation of and toxicity testing with marine copepod Acartia tonsa

    SciTech Connect

    Kusk, K.O.; Wollenberger, L.

    1999-07-01

    The marine copepod Acartia tonsa and the food organism Rhodomonas salina were cultured in fully defined medium for 8 months without problems. Both organisms were also cultured in natural seawater and in a commercial salt mixture for at least two generations before the sensitivities of A. tonsa to bisphenol A, potassium dichromate, and 3,5-dichlorophenol in the three different media were compared and found to be at the same level. The defined medium may be used for cultivation and testing, thus avoiding unknown background contaminants.

  14. Development and reproduction of the freshwater harpacticoid copepod Attheyella crassa for assessing sediment-associated toxicity.

    PubMed

    Turesson, Eva Ulfsdotter; Stiernstrm, Sara; Minten, Johanna; Adolfsson-Erici, Margaretha; Bengtsson, Bengt-Erik; Breitholtz, Magnus

    2007-07-20

    Both freshwater and marine sediments are sinks for many anthropogenic substances. This may pose a risk to benthic and epibenthic organisms and it is crucial that toxicity tests that are available for environmental risk assessment can identify potentially adverse effects of sediment-associated substances on benthic organisms, such as harpacticoid copepods. While marine harpacticoids have been protected via a number of acute and chronic sediment tests, the freshwater harpacticoid copepod community has so far been neglected in such activities. The main aim of the present study was therefore to (a) find a suitable freshwater harpacticoid copepod, (b) establish robust laboratory mass cultures and (c) develop a chronic test for assessment of sediment-associated toxicity using spiked sediments. After several cultivation trials with a number of potential test species, the choice fell on the benthic freshwater harpacticoid copepod Attheyella crassa, a species that possesses many of the characteristic features identified as prerequisites for toxicity test organisms, e.g. it has a sexual reproduction, it is relatively easy to grow and keep in mass cultures in the laboratory, and it has a small body size. Owing to the relatively long generation time of freshwater harpacticoids (in relation to many marine harpacticoids), it was decided that the test should be separated into a development part (21 days) and a reproduction part (14 days) running in parallel. As a reference substance we used the fungicide tebuconazole, which is currently subject to risk assessment and which partitions to soil and sediment. Clear concentration-related responses were observed for all endpoints analyzed. Nauplia body length was the most sensitive endpoint with a measured time weighted LOEC(water) of 20microg/L. The corresponding LOEC(water) for larval mortality and offspring production was 65 and 62microg/L, respectively. In conclusion, A. crassa is an ecologically relevant test species for freshwater ecosystems and particularly for the cold, oligotrophic and often acidic lakes of Northern Europe. Regardless of the relatively long generation time of this species, our results clearly show that sediment-associated toxicity related to development and sexual reproduction can be assessed within 2-3 weeks exposure with the developed bioassay. PMID:17512064

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

    SciTech Connect

    Verriopoulos, G.; Dimas, S.

    1988-09-01

    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.

  16. The toxicological interaction between ocean acidity and metals in coastal meiobenthic copepods.

    PubMed

    Pascal, Pierre-Yves; Fleeger, John W; Galvez, Fernando; Carman, Kevin R

    2010-12-01

    Increased atmospheric CO(2) concentrations are causing greater dissolution of CO(2) into seawater, and are ultimately responsible for today's ongoing ocean acidification. We manipulated seawater acidity by addition of HCl and by increasing CO(2) concentration and observed that two coastal harpacticoid copepods, Amphiascoides atopus and Schizopera knabeni were both more sensitive to increased acidity when generated by CO(2). The present study indicates that copepods living in environments more prone to hypercapnia, such as mudflats where S. knabeni lives, may be less sensitive to future acidification. Ocean acidification is also expected to alter the toxicity of waterborne metals by influencing their speciation in seawater. CO(2) enrichment did not affect the free-ion concentration of Cd but did increase the free-ion concentration of Cu. Antagonistic toxicities were observed between CO(2) with Cd, Cu and Cu free-ion in A. atopus. This interaction could be due to a competition for H(+) and metals for binding sites. PMID:20875652

  17. Effects of pyrene exposure and temperature on early development of two co-existing Arctic copepods.

    PubMed

    Grenvald, Julie Cornelius; Nielsen, Torkel Gissel; Hjorth, Morten

    2013-01-01

    Oil exploration is expected to increase in the near future in Western Greenland. At present, effects of exposure to oil compounds on early life-stages of the ecologically important Calanus spp. are unknown. We investigated the effects of the oil compound pyrene, on egg hatching and naupliar development of the calanoid copepods Calanus glacialis and C. finmarchicus, two key species in the Disko Bay, Western Greenland. At low temperature the nauplii of C. glacialis experienced reduced growth when exposed to pyrene, and survival in both species decreased. Naupliar mortality increased with temperature at high pyrene concentration in C. finmarchicus. Both Calanus species were affected by pyrene exposure but C. finmarchicus was more sensitive compared to C. glacialis. Lowered growth rate and increased mortality of the naupliar stages entail reduced recruitment to copepod populations. Exposure to pyrene from an oil spill may reduce the standing stock of Calanus, which can lead to less energy available to higher trophic levels in the Arctic marine food web. PMID:23143803

  18. The need for speed. I. Fast reactions and myelinated axons in copepods.

    PubMed

    Lenz, P H; Hartline, D K; Davis, A D

    2000-04-01

    A rapid and powerful escape response decreases predation risk in planktonic copepods. Calanoid copepods are sensitive to small and brief hydrodynamic disturbances: they respond with multiple nerve impulses to a vibrating sphere. Some species, such as Pleuromamma xiphias and Labidocera madurae, respond with very large spikes (1-4 mV), whereas maximum spike heights are an order of magnitude smaller in others, such as Undinula vulgaris and Neocalanus gracilis. A comparative study of the escape responses showed that all species reacted within 10 ms of the initiation of a hydrodynamic stimulus. However, U. vulgaris and N. gracilis had significantly shorter reaction times (minimum reaction times: 1.5 ms and 1.6 ms) than the other two, P. xiphias (6.6 ms) and L. madurae (3.1 ms). Examination of the first antenna and the central nervous system using transmission electron microscopy revealed extensive myelination of sensory and motor axons in the two species with the shorter reaction times. Axons of the other two species resembled typical crustacean unmyelinated fibers. A survey of 20 calanoids revealed that none of the species in two of the more ancient superfamilies possessed myelin, but myelination was present in the species from three more recently-evolved superfamilies. PMID:10798722

  19. Seasonal variation in the copepod community structure from a tropical Amazon estuary, Northern Brazil.

    PubMed

    Magalhães, André; Leite, Natália da R; Silva, João G S; Pereira, Luci C C; Costa, Rauquírio M da

    2009-06-01

    The main purpose of this study was to investigate the seasonal variation of copepod community structure during the months of July, September and November 2003 (dry season) and January, March and May 2004 (rainy season) in the Curuçá estuary, northern Brazil. Samples were collected during neap tides via gentle 200microm mesh net tows from a small powerboat. Measurements of surface water conductivity were accomplished in situ using an electronic conductivimeter and salinity was later obtained through the transformation of the conductivity values. Salinity varied seasonally from 7.2 +/- 0.1 to 39.2 +/- 1.8 (mean +/- standard deviation) and was influenced mainly by differences in the amount of rainfall between the studied sampling seasons. In total, 30 Copepoda taxa were identified and Acartia tonsa comprised the most representative species throughout the entire studied period followed by Acartia lilljeborgii, Subeucalanus pileatus and Paracalanus quasimodo. In the present study, the density values, ecological indexes and copepod species dominance presented a clear seasonal pattern, showing that the studied area may be considered seasonally heterogeneous in relation to the investigated parameters. PMID:19488623

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

    PubMed

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

    2008-09-01

    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

  1. Egg production rates of two common copepods in the Barents Sea in summer

    NASA Astrophysics Data System (ADS)

    Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

    2014-09-01

    Small copepod species play important roles in the pelagic food webs of the Arctic Ocean, linking primary producers to higher trophic levels. The egg production rates (EPs) and weight-specific egg production rates (SEPs) of two common copepods, Acartia longiremis and Temora longicornis, were studied under experimental conditions in Dalnezelenetskaya Bay (southern Barents Sea) during summer. The average EP and SEP at 5-10 C were 4.7 0.4 eggs female-1 day-1 and 0.025 0.002 day-1, respectively, for A. longiremis and 13.1 0.9 eggs female-1 day-1 and 0.075 0.006 day-1, respectively, for T. longicornis. EP and SEP were significantly higher at 10C than at 5C for both species. The mean egg diameter correlated positively and significantly with female prosome length (PL) in each species. SEP of T. longicornis correlated negatively and significantly with PL. Daily EP and SEP were similar to rates recorded for other Acartia and Temora species in temperate and warm regions. The influence of environmental factors (temperature, salinity, and phytoplankton concentration) on EP of both species is discussed. We conclude that temperature is the main factor determining the reproduction rate and timing in A. longiremis and T. longicornis in the Barents Sea.

  2. Limited feeding on bacteria by two intertidal benthic copepod species as revealed by trophic biomarkers.

    PubMed

    Cnudde, Clio; Moens, Tom; Hoste, Bart; Willems, Anne; De Troch, Marleen

    2013-04-01

    Harpacticoids can discriminate between biofilms of different bacterial strains. We investigated whether assimilation of bacteria is selective and whether harpacticoids select for the most nutritional bacteria. We specifically focused on the role of bacterial characteristics in copepod food selection. Trophic biomarkers (stable isotopes, fatty acids) were used to test selective assimilation of three bacteria by the harpacticoids Platychelipus littoralis and Delavalia palustris, all isolated from a salt marsh. The bacteria Gramella sp., Jannaschia sp. and Photobacterium sp. with contrasting ribosomal protein and fatty acid contents were (13)C-labelled and offered in a food patch choice experiment with monospecific and combination treatments (single and two strains per microcosm respectively). Low assimilation of bacterial carbon and lack of significant fatty acid transfer proved that bacteria were a poor food source for the harpacticoids. Assimilation was copepod species-specific and bacteria strain-specific (preference for Photobacterium). However, only a low degree of selective feeding occurred; it can partly be explained by bacterial extracellular metabolites rather than by biochemical content and densities. Finally, the energetic cost of differential bacterivory resulted in a negative fatty acid balance for Platychelipus, while Delavalia showed an improved fatty acid profile and thus a positive response to the low-quality bacterial food. PMID:23589378

  3. Effects of dispersed oil on reproduction in the cold water copepod Calanus finmarchicus (Gunnerus)

    PubMed Central

    Olsen, Anders Johny; Nordtug, Trond; Altin, Dag; Lervik, Morten; Hansen, Bjørn Henrik

    2013-01-01

    Following a 120-h exposure period to 3 concentrations of oil dispersions (0.022 mg L−1, 1.8 mg L−1, and 16.5 mg L−1, plus controls) generated from a North Sea crude oil and a subsequent 21-d recovery, mortality, and several reproduction endpoints (egg production rates, egg hatching success, and fraction of females participating in reproduction) in Calanus finmarchicus were studied. Concentration-dependent mortality was found during exposure, averaging to 6%, 3%, 15%, and 42% for the controls and 3 exposure levels, respectively. At the start of the recovery period, mean egg production rates of surviving females from the highest concentrations were very low, but reproduction subsequently improved. In a 4-d single female reproduction test starting 13 d postexposure, no significant differences in egg production rates or hatching success were found between reproducing control and exposed copepods. However, a significantly lower portion of the surviving females from the highest exposure participated in egg production. The results indicate that although short-term exposure to oil-polluted water after an oil spill can induce severe mortality and temporarily suspend reproduction, copepods may recover and produce viable offspring soon after exposure. The results might imply that for C. finmarchicus populations, the impact from short-term exposure to an oil spill might be predicted from acute mortality and that delayed effects make only a limited contribution to population decrease. PMID:23661343

  4. Aqueous-, pore-water-, and sediment-phase cadmium: Toxicity relationships for a meiobenthic copepod

    SciTech Connect

    Green, A.S.; Chandler, G.T.; Blood, E.R. . Dept. of Environmental Health Sciences)

    1993-08-01

    Comparative effects of aqueous-, pore-water-, and sediment-phase cadmium on mortality of an infaunal laboratory-cultured copepod, Amphiascus tenuiremis, were determined using acute 96-h bioassays. Experimental design included five cadmium concentrations, three replicates per concentration, and 50 adult copepods per replicate for each of the exposure. Exposures included cadmium solubilized in seawater only, whole sediment, and pore water only. In addition, two whole-sediment bioassays were compared in which pore-water cadmium concentrations were altered experimentally but sediment concentrations remained the same. Results of these experiments showed that for Amphiascus tenuiremis, cadmium is most toxic in the aqueous phase, less toxic in the pore-water phase, and last toxic in the sediment-bound phase. The lowered toxicity of cadmium in the pore water was most likely due to complexation of cadmium with DOC, because concentrations of DOC were six times higher in the pore-water phase than in the aqueous phase. In whole sediments, pore-water-phase cadmium was the primary source of acute toxicity, as sediment-associated cadmium contributed negligible effects.

  5. Effect of chemically contaminated marine sediment on naupliar production of the marine harpacticoid copepod, Tigriopus californicus

    SciTech Connect

    Misitano, D.A.; Schiewe, M.H. )

    1990-04-01

    There is a growing body of evidence indicating that chemically contaminated sediments in urban bays and estuaries pose a significant threat to the productivity of these important marine habitats. Particularly at risk are benthic species which live in direct contact with the sediment. However, nondemersal species are also at risk via the food chain and by direct contact with resuspended sediment particulates. There are substantial data on the lethal and sublethal effects of aqueous contaminants on a variety of aquatic species. In contrast, there is very limited information on the toxic effects of the generally water-insoluble sediment-associated contaminants. In the present communication the authors report a series of experiments in which the harpacticoid copepod, Tigriopus californicus, was exposed to sediments from urban and nonurban bays, and reproductive success was evaluated. This species was selected for study as it is widely distributed along the West Coast of North America, and as a group, copepods are an important component of the marine food chain. In addition, the relatively short reproductive life span of this species makes it particularly amenable for studies of reproductive success. Here, the authors report reduced and irregular naupliar production as a consequence of exposure to chemically contaminated sediments from urban waterways.

  6. A model study with light-dependent mortality rates of copepod stages

    NASA Astrophysics Data System (ADS)

    Neumann, Thomas; Kremp, Christine

    2005-06-01

    This paper is based on an advanced ecosystem model of the Baltic Sea (ERGOM [ J. Mar. Sys. 25 (3-4) (2005) 405]), but with an increased resolution of the zooplankton stage variable [ J. Plankton Res. 23 (2001) 1217; ICES Marine Science 219 (2003) 208]. The model copepods are represented by five stages: eggs, an aggregated variable of nauplii, two aggregated groups of copepodites and adults. The transfer among the stages, i.e., hatching, molting and reproduction, is controlled by food availability and temperature. As usual, the model food web is truncated at the level of zooplankton. The study explores the effects of different parametrization of zooplankton mortality and looks in particular on light-dependent rates. The light climate may serve a proxy for the effects of visual feeding of fish larvae and fish. Different choices of the mortality parameters can result in remarkable differences in abundances and biomass of the model zooplankton and in the timing of its development. It is found that the different choices of mortality affect the development of populations in several ways: Relative small initial differences of abundances at the beginning of the spring bloom are important for the development of the model populations. Higher mortality rates are less important at food rich conditions than at scarce resources. At low phytoplankton levels, the individual development of the copepods through the stages can be faster for elevated mortality rates because then less animals have to share the available food.

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

    PubMed

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

    2014-09-01

    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) g L(-1). In the 12-h avoidance assay, 30% avoidance was recorded at the highest PAH concentration (19.4 g 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

  8. Modeling filtration of dispersed crude oil droplets by the copepod Calanus finmarchicus.

    PubMed

    Nepstad, Raymond; Strdal, Ingvild Fladvad; Brnner, Ute; Nordtug, Trond; Hansen, Bjrn Henrik

    2015-04-01

    Oil droplets may form and disperse in the water column after an accidental spill of crude oil or petroleum products at sea. Micro-sized oil droplets may be available for filter feeding organisms, such as the copepod Calanus finmarchicus, which has been shown to filter oil droplets. In the present paper, a modeling approach was used to estimate potential ingestion amounts by copepod filtration of oil droplets. The new model was implemented in the OSCAR (Oil Spill Contingency and Response) software suite, and tested for a series of oil spill scenarios and key parameters. Among these, the size of the filtered droplets was found to be the most important factor influencing the model results. Given the assumptions and simplifications of the model, filtration of dispersed crude oil by C. finmarchicus was predicted to affect the fate of 1-40% of the total released oil mass, depending on the release scenario and parameter values used, with the lower end of that range being more probable in an actual spill situation. PMID:25636164

  9. Modeling filtration of dispersed crude oil droplets by the copepod Calanus finmarchicus.

    TOXLINE Toxicology Bibliographic Information

    Nepstad R; Strdal IF; Brnner U; Nordtug T; Hansen BH

    2015-04-01

    Oil droplets may form and disperse in the water column after an accidental spill of crude oil or petroleum products at sea. Micro-sized oil droplets may be available for filter feeding organisms, such as the copepod Calanus finmarchicus, which has been shown to filter oil droplets. In the present paper, a modeling approach was used to estimate potential ingestion amounts by copepod filtration of oil droplets. The new model was implemented in the OSCAR (Oil Spill Contingency and Response) software suite, and tested for a series of oil spill scenarios and key parameters. Among these, the size of the filtered droplets was found to be the most important factor influencing the model results. Given the assumptions and simplifications of the model, filtration of dispersed crude oil by C. finmarchicus was predicted to affect the fate of 1-40% of the total released oil mass, depending on the release scenario and parameter values used, with the lower end of that range being more probable in an actual spill situation.

  10. Toxicity of nickel in the marine calanoid copepod Acartia tonsa: Nickel chloride versus nanoparticles.

    PubMed

    Zhou, C; Vitiello, V; Casals, E; Puntes, V F; Iamunno, F; Pellegrini, D; Changwen, W; Benvenuto, G; Buttino, I

    2016-01-01

    Nickel compounds are widely used in industries and have been massively introduced in the environment in different chemical forms. Here we report the effect of two different chemical forms of nickel, NiCl2 and nickel nanoparticles (NiNPs), on the reproduction of the marine calanoid copepod Acartia tonsa. The behavior of nickel nanoparticles was analyzed with different techniques and with two protocols. In the "sonicated experiment" (SON) NiNP solution was sonicated while in the "non-sonicated experiment" (NON-SON) the solution was vigorously shaken by hand. Final nominal concentrations of 5, 10 and 50mgL(-1) and 1, 5 and 10mgL(-1) NiNPs were used for the acute and semichronic tests, respectively. Nanoparticle size did not change over time except for the highest concentration of 50mgL(-1) NiNPs, in which the diameter increased up to 843nm after 48h. The concentration of Ni dissolved in the water increased with NP concentration and was similar for SON and NON-SON solutions. Our results indicate that sonication does not modify toxicity for the copepod A. tonsa. Mean EC50 values were similar for NON-SON (20.2mgL(-1)) and SON experiments (22.14mgL(-1)) in the acute test. Similarly, no differences occurred between the two different protocols in the semichronic test, with an EC50 of 7.45mgL(-1) and 6.97mgL(-1) for NON-SON and SON experiments, respectively. Acute and semichronic tests, conducted exposing A. tonsa embryos to NiCl2 concentrations from 0.025 to 0.63mgL(-1), showed EC50 of 0.164 and 0.039mgL(-1), respectively. Overall, A. tonsa is more sensitive to NiCl2 than NiNPs with EC50 being one order of magnitude higher for NiNPs. Finally, we exposed adult copepods for 4 days to NiCl2 and NiNPs (chronic exposure) to study the effect on fecundity in terms of daily egg production and naupliar viability. Egg production is not affected by either form of nickel, whereas egg viability is significantly reduced by 0.025mgL(-1) NiCl2 and by 8.5mgL(-1) NiNPs. At NiNP concentration below the acute EC50 (17mgL(-1)) only 9% of embryos hatched after 4 days. Interestingly, the percentage of naupliar mortality (>82%) observed in the semichronic test at the nominal concentration of 10mgL(-1) NiNPs corresponding to almost 0.10mgL(-1) of dissolved Ni, was similar to that recorded at the same Ni salt concentration. Electron microscopical analyses revealed that A. tonsa adults ingest NiNPs and excrete them through fecal pellets. To the best of our knowledge, this is the first study investigating the toxicity of two different forms of Ni on the reproductive physiology of the copepod A. tonsa and showing the ability of the calanoid copepod to ingest nanoparticles from seawater. PMID:26562184

  11. UTILITY OF A FULL LIFE-CYCLE COPEPOD BIOASSAY APPROACH FOR ASSESSMENT OF SEDIMENT-ASSOCIATED CONTAMINANT MIXTURES. (R825279)

    EPA Science Inventory

    Abstract

    We compared a 21 day full life-cycle bioassay with an existing 14 day partial life-cycle bioassay for two species of meiobenthic copepods, Microarthridion littorale and Amphiascus tenuiremis. We hypothesized that full life-cycle tests would bette...

  12. 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...

  13. 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...

  14. Effects of the oxylipin-producing diatom Skeletonema marinoi on gene expression levels of the calanoid copepod Calanus sinicus.

    PubMed

    Lauritano, Chiara; Carotenuto, Ylenia; Vitiello, Valentina; Buttino, Isabella; Romano, Giovanna; Hwang, Jiang-Shiou; Ianora, Adrianna

    2015-12-01

    Diatoms are eukaryotic unicellular plants that constitute one of the major components of marine phytoplankton, comprising up to 40% of annual productivity at sea and representing 25% of global carbon-fixation. Diatoms have traditionally been considered a preferential food for zooplankton grazers such as copepods, but, in the last two decades, this beneficial role has been challenged after the discovery that many species of diatoms produce toxic metabolites, collectively termed oxylipins, that induce reproductive failure in zooplankton grazers. Diatoms are the dominant natural diet of Calanus sinicus, a cold-temperate calanoid copepod that supports secondary production of important fisheries in the shelf ecosystems of the Northwest Pacific Ocean, Yellow Sea, Sea of Japan and South China Sea. In this study, the effect of the oxylipin-producing diatom Skeletonema marinoi on C. sinicus has been evaluated by analyzing expression level changes of genes involved in defense and detoxification systems. Results show that C. sinicus is more resistant to a diet of this diatom species in terms of gene expression patterns, compared to the congeneric species Calanus helgolandicus which is an important constituent of the temperate waters of the Atlantic Ocean and northern Mediterranean Sea. These findings contribute to the better understanding of genetic and/or phenotypic flexibility of copepod species and their capabilities to cope with stress by identifying molecular markers (such as stress and detoxification genes) as biosensors for environmental perturbations (e.g. toxins and contaminants) affecting marine copepods. PMID:25666254

  15. Sensitivity of the larvivorous copepod species, Mesocyclops pehpeiensis and Megacyclops viridis, to the insect growth regulator, pyriproxyfen.

    PubMed

    Wang, Shanqing; Phong, Tran Vu; Tuno, Nobuko; Kawada, Hitoshi; Takagi, Masahiro

    2005-12-01

    The effects of the insect growth regulator pyriproxyfen were evaluated on the mortality, fecundity, longevity, and predation capability of 2 species of copepods, Mesocyclops pehpeiensis Hu and Megacyclops viridis (Jurine), under laboratory conditions. Pyriproxyfen showed no significant effects on either the development or reproduction of M. pehpeiensis at 0.1 ppm, which is a 10-fold greater concentration than the reported effective dosage for controlling mosquito larvae (0.01 ppm). In contrast, the development of M. viridis was impaired by pyriproxyfen at 0.1 ppm. An 80% reduction in nauplius survivorship was observed in the experimental (treated) group compared with the control group. Although the application of pyriproxyfen caused high mortality in the nauplius stage of this species, the pyriproxyfen-treated group developed faster, killed more mosquito larvae, yielded more eggs per oviposition event, and survived longer than the control group. These results indicate that pyriproxyfen caused mortality in the earlier stages of this sensitive species but that the surviving individuals were those that were selected for significantly faster development, better predation ability, and greater longevity during their reproductive stage. Therefore, under natural conditions, pyriproxyfen would cause modifications in the characteristics of a copepod population rather than its complete loss. Our results suggest that the combined application of copepods and pyriproxyfen to control Aedes populations is feasible. However, repeated application of pyriproxyfen may cause changes in copepod populations and communities in the affected ecosystem. PMID:16506581

  16. Relationships between copepod community structure, rainfall regimes, and hydrological variables in a tropical mangrove estuary (Amazon coast, Brazil)

    NASA Astrophysics Data System (ADS)

    Magalhães, André; Pereira, Luci Cajueiro Carneiro; da Costa, Rauquírio Marinho

    2015-03-01

    The influence of rainfall and hydrological variables on the abundance and diversity of the copepod community was investigated on a monthly basis over an annual cycle in the Taperaçu mangrove estuary. In general, the results show that there were no clear spatial or tidal patterns in any biological variables during the study period, which was related to the reduced horizontal gradient in abiotic parameters, determined mainly by the morphological and morphodynamic features of the estuary. Nevertheless, seasonal and monthly trends were recorded in both the hydrological data and the abundance of the dominant copepod species. In particular, Pseudodiaptomus marshi (6,004.6 ± 22,231.6 ind m-3; F = 5.0, p < 0.05) and Acartia tonsa (905.6 ± 2,400.9 ind m-3; F = 14.6, p < 0.001) predominated during the rainy season, whereas Acartia lilljeborgii (750.8 ± 808.3 ind m-3; U = 413.0, p < 0.01) was the most abundant species in the dry season. A distinct process of succession was observed in the relative abundance of these species, driven by the shift in the rainfall regime, which affected hydrological, in particular salinity, and consequently the abundance of copepod species. We suggest that this may be a general pattern governing the dynamics of copepod populations in the estuaries of the Brazilian Amazonian region.

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

    SciTech Connect

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

    2000-04-01

    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.

  18. Effects of high CO2 seawater on the copepod (Acartia tsuensis) through all life stages and subsequent generations.

    PubMed

    Kurihara, Haruko; Ishimatsu, Atsushi

    2008-06-01

    We studied the effects of exposure to seawater equilibrated with CO(2)-enriched air (CO(2) 2380 ppm) from eggs to maturity and over two subsequent generations on the copepod Acartia tsuensis. Compared to the control (CO(2) 380 ppm), high CO(2) exposure through all life stages of the 1st generation copepods did not significantly affect survival, body size or developmental speed. Egg production and hatching rates were also not significantly different between the initial generation of females exposed to high CO(2) and the 1st and 2nd generation females developed from eggs to maturity in high CO(2). Thus, the copepods appear more tolerant to increased CO(2) than other marine organisms previously investigated for CO(2) tolerance (i.e., sea urchins and bivalves). However, the crucial importance of copepods in marine ecosystems requires thorough evaluation of the overall impacts of marine environmental changes predicted to occur with increased CO(2) concentrations, i.e., increased temperature, enhanced UV irradiation, and changes in the community structure and nutritional value of phytoplankton. PMID:18455195

  19. Temperature Affects the Use of Storage Fatty Acids as Energy Source in a Benthic Copepod (Platychelipus littoralis, Harpacticoida)

    PubMed Central

    Werbrouck, Eva; Van Gansbeke, Dirk; Vanreusel, Ann; De Troch, Marleen

    2016-01-01

    The utilization of storage lipids and their associated fatty acids (FA) is an important means for organisms to cope with periods of food shortage, however, little is known about the dynamics and FA mobilization in benthic copepods (order Harpacticoida). Furthermore, lipid depletion and FA mobilization may depend on the ambient temperature. Therefore, we subjected the temperate copepod Platychelipus littoralis to several intervals (3, 6 and 14 days) of food deprivation, under two temperatures in the range of the normal habitat temperature (4, 15°C) and under an elevated temperature (24°C), and studied the changes in FA composition of storage and membrane lipids. Although bulk depletion of storage FA occurred after a few days of food deprivation under 4°C and 15°C, copepod survival remained high during the experiment, suggesting the catabolization of other energy sources. Ambient temperature affected both the degree of FA depletion and the FA mobilization. In particular, storage FA were more exhausted and FA mobilization was more selective under 15°C compared with 4°C. In contrast, depletion of storage FA was limited under an elevated temperature, potentially due to a switch to partial anaerobiosis. Food deprivation induced selective DHA retention in the copepod’s membrane, under all temperatures. However, prolonged exposure to heat and nutritional stress eventually depleted DHA in the membranes, and potentially induced high copepod mortality. Storage lipids clearly played an important role in the short-term response of the copepod P. littoralis to food deprivation. However, under elevated temperature, the use of storage FA as an energy source is compromised. PMID:26986852

  20. EFFECTS OF DIET ON GROWTH AND SURVIVAL OF LARVAL WALLYES

    EPA Science Inventory

    The effects of diet quality on larval walleye (Stizostedion vitreum vitreum) growth and survival are described. The cyclopoid copepod Diacyclops thomasi consumed larval walleyes within 10 min at dense copepod concentrations and within 1 day at lower densities (500 organisms/L). A...

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

    NASA Astrophysics Data System (ADS)

    Yi, Xiaoyan; Zhang, Huan; Liu, Guangxing

    2014-05-01

    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.

  2. Observations on a lesser-known monogenean, Udonella myliobati, from a copepod parasite, Lepeophtheirus natalensis, parasitizing the spotted ragged-tooth shark, Carcharias taurus, from South African waters.

    PubMed

    Olivier, P A; Dippenaar, S M; Khalil, L F; Mokgalong, N M

    2000-06-01

    The phylogeny of the genus Udonella has been disputed for quite some time, but recent phylogenetic analysis of molecular data confirms that the genus is a monopisthocotylean monogenean. Specimens of Udonella myliobati parasitizing the copepod Lepeophtheirus natalensis, an ectoparasite of the spotted ragged-tooth shark, (Carcharias taurus), were collected and studied. A total of 771 monogenean specimens were recovered from 54 infected copepods examined, with a mean intensity of 14,3 worms per copepod. Most of the monogeneans were found attached to the dorsal surface of the lateral and frontal marginal membranes of the copepod carapace. Eggs, with filaments and adhesive discs, were found ventrally on the host, mainly attached to the maxillae and maxillipeds, in clusters of 12-14. Observations on the morphology, distribution and behaviour of this monogenean are presented with the aid of light and scanning electron microscopy. PMID:11028750

  3. Summer population structure of the copepods Paraeuchaeta spp. in the Kara Sea

    NASA Astrophysics Data System (ADS)

    Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

    2015-02-01

    High Arctic seas are poorly studied due to difficulties to access and sample seas with extensive sea ice cover. The current study investigated the distribution of the large deepwater copepods Paraeuchaeta spp. (Paraeuchaeta glacialis) in the summer season in the Kara Sea. The total abundance of P. glacialis varied from 10 to 1210 × 10- 2 ind m- 3 sampled with a Juday net and from 2 to 490 × 10- 2 ind m- 3 sampled with a IKS-80 net. The highest abundances were recorded at the deepwater stations. Nauplii dominated the population of Paraeuchaeta spp. comprising 23% of the total abundance. Unimodal size spectra were found for most of the age stages that suggests the presence of one generation during the year. Clutch size and egg size tended to increase with P. glacialis female prosome length and individual biomass.

  4. Hydrodynamics and spatial separation between two clades of a copepod species complex

    NASA Astrophysics Data System (ADS)

    St-Onge-Drouin, Simon; Winkler, Gesche; Dumais, Jean-Franois; Senneville, Simon

    2014-01-01

    The purpose of this study was to explore the importance of hydrodynamics in the spatial distribution of a dominant calanoid copepod, Eurytemora affinis, in the middle St. Lawrence Estuary. To do this, we used a 3D numerical model of the region. We successfully compared modelled trajectories to real trajectories obtained from surface drifters. Multiple trajectories were then generated to compute finite-time Lyapunov exponents (FTLEs). A ridge of high FTLE values, which starts downstream close to the shoal between le-aux-Coudres and Ste-Annes Bay and reaches its upstream extremity on the south shore near Montmagny, separates two groups of modelled particles. This ridge seems to separate two distinct water masses that will not mix together. It appears 1 h after high tide and is persistent for 3 to 4 h during every ebb tide, suggesting that hydrodynamics is an important factor maintaining the separation between the two genetically different E. affinis clades.

  5. Mitochondrial DNA polymorphism (CO1) of three dominant copepod species in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Stupnikova, A. N.; Kulagin, D. N.; Neretina, T. V.; Mugue, N. S.

    2013-07-01

    The Southern Ocean is characterized by the complex system of oceanic fronts that maintain the latitudinal zonality of biotopes. These fronts are boundaries of water masses with different hydrophysical characteristics. We explore the genetic differentiation of the dominant zooplankton species in regards to the complex hydrophysical zonality of the Southern Ocean. The barcoding region of mitochondrial CO1 gene was sequenced for three copepod species, Calanus simillimus, Rhincalanus gigas, and Metridia lucens. These species are the most abundant in the Southern Ocean and form the basis of the zooplankton community. Genetic differentiation was found neither for Calanus simillimus nor for Rhincalanus gigas. The mitochondrial haplotypes of Metridia lucens cluster in two genetically distant groups (Subantarctic and Antarctic) found together only in the Polar Front Zone.

  6. Biosynthesis of coelenterazine in the deep-sea copepod, Metridia pacifica

    SciTech Connect

    Oba, Yuichi; Kato, Shin-ichi; Ojika, Makoto; Inouye, Satoshi

    2009-12-18

    Coelenterazine is an imidazopyrazinone compound (3,7-dihydroimidazopyrazin-3-one structure) that is widely distributed in marine organisms and used as a luciferin for various bioluminescence reactions. We have used electrospray ionization-ion trap-mass spectrometry to investigate whether the deep-sea luminous copepod Metridia pacifica is able to synthesize coelenterazine. By feeding experiments using deuterium labeled amino acids of L-tyrosine and L-phenylalanine, we have shown that coelenterazine can be synthesized from two molecules of L-tyrosine and one molecule of L-phenylalanine in M. pacifica. This is the first demonstration that coelenterazine is biosynthesized from free L-amino acids in a marine organism.

  7. Bacterial exopolymer utilization by a harpacticoid copepod: A methodology and results

    SciTech Connect

    Decho, A.W.; Moriarty, D.J.W. )

    1990-07-01

    Exopolymer mucus secretions of bacteria and diatoms are potential foods for benthic animals. These secretions are coincidently ingested by animals during consumption of microbial cells and sediments. The utilization of microbial secretions was investigated with exopolymer derived from a marine bacterium (pseudomonas sp.) from seagrass beds and a harpacticoid copepod Laophonte sp. from the same habitat. A new technique was developed to examine ingestion, absorption, and absorption efficiencies of these bacterial secretions by consumers. Exopolymer mucus (from the bacterium in stationary phase) was labeled with {sup 14}C, collected, purified, and bound onto bacterium-sized beads. The exopolymer slime coating mimicked the coatings associated with many marine bacteria. Results from feeding experiments where the coated beads were mixed with sediment demonstrated that the mucus-exopolymer secretions of bacteria were ingested and utilized by Laophonte sp. Absorption efficiencies, determined directly, were > 80% in the presence of other food resources, indicating that exopolymer is potentially a highly labile C resource for this animal.

  8. Copepod communities in the estuary and coastal plume of the Hudson River

    NASA Astrophysics Data System (ADS)

    Stepien, Jeanne C.; Malone, Thomas C.; Chervin, Mira B.

    1981-08-01

    Copepods were the most abundant group of macrozooplankton in the estuary and plume of the Hudson River. Seasonal variations in abundance were similar but different species dominated in the two systems. A distinct succession of species was observed in the estuary while the same group of species dominated throughout the year in the plume. Species associations in the estuary were affected by seasonal variations in temperature and salinity while river flow, storms, and large-scale circulation on the continental shelf influenced species associations in the plume. Seasonal increases in abundance during spring and summer within the plume appeared to be primarily due to growth within the system rather than to lateral transport from the estuary or offshore continental shelf environments.

  9. Syltodinium listii gen. et spec. nov., a marine ectoparasitic dinoflagellate on eggs of copepods and rotifers

    NASA Astrophysics Data System (ADS)

    Drebes, Gerhard

    1988-09-01

    Syltodinium listii is described as a new marine ectoparasitic dinoflagellate. In culture experiments the species was found feeding on eggs of planktonic copepods and rotifers. The dinospore penetrates the host by a peduncle, and transforms into a trophont by sucking out the egg contents phagotrophically. After detaching from the host, the mature trophont settles down to become a palmelloid multiplication stage. By repeated binary fission, up to 16 or 32 gymnodinoid, colourless dinospores are formed inside a gelatinous envelope. The parasite retains its dinoflagellate (monadoid) nature throughout its whole vegetative life cycle. Even during the trophic and multiplication phase the species remains latently motile. Despite some resemblance to Dissodinium, there are sufficient reasons for the establishment of the new genus Syltodinium.

  10. Revisiting the octopicolid copepods (Octopicolidae: Octopicola Humes, 1957): comparative morphology and an updated key to species.

    PubMed

    Cavaleiro, Francisca I; Ho, Ju-Shey; Iglesias, Raúl; García-Estévez, José M; Santos, Maria J

    2013-09-01

    A review of the present state of knowledge on the octopicolid copepods (Octopicolidae: Octopicola Humes, 1957) is presented. Characteristic morphological features are illustrated with scanning electron micrographs of Octopicola superba superba Humes, 1957. Comparative morphology analysis led to the conclusion that there is sufficient evidence to justify raising the two subspecies of O. superba to full species rank. A new identification key for the four species of Octopicola Humes, 1957, i.e. O. superba Humes, 1957, O. antillensis Stock, Humes & Gooding, 1963, O. stocki Humes, 1963 and O. regalis Humes, 1974, is proposed after evaluation of the morphological characters which vary more markedly between them. Among other characters, these species differ in the ornamentation of the third antennal segment, maxilla and male maxilliped. They are further distinguished by a combination of several character states concerning the fifth pedigerous somite. PMID:23949652

  11. Changes in Selection Regime Cause Loss of Phenotypic Plasticity in Planktonic Freshwater Copepods

    PubMed Central

    Sereda, Sergej Vitalevi?; Wilke, Thomas; Schulthei, Roland

    2014-01-01

    Rapid phenotypic adaptation is critical for populations facing environmental changes and can be facilitated by phenotypic plasticity in the selected traits. Whereas recurrent environmental fluctuations can favour the maintenance or de novo evolution of plasticity, strong selection is hypothesized to decrease plasticity or even fix the trait (genetic assimilation). Despite advances in the theoretical understanding of the impact of plasticity on diversification processes, comparatively little empirical data of populations undergoing diversification mediated by plasticity are available. Here we use the planktonic freshwater copepod Acanthodiaptomus denticornis from two lakes as model system to study UV stress responses of two phenotypically different populations under laboratory conditions. Our study reveals heritable lake- and sex-specific differences of behaviour, physiological plasticity, and mortality. We discuss specific selective scenarios causing these differences and argue that phenotypic plasticity will be higher when selection pressure is moderate, but will decrease or even be lost under stronger pressure. PMID:24587186

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

    PubMed

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

    2014-09-01

    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

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

    NASA Astrophysics Data System (ADS)

    Hagen, Wilhelm; Schnack-Schiel, Sigrid B.

    1996-02-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Eisfeld, Sonja M.; Niehoff, Barbara

    2007-09-01

    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.

  15. Copepod colonization of natural and artificial substrates in a salt marsh pool

    NASA Astrophysics Data System (ADS)

    Cummings, Eileen; Ruber, Ernest

    1987-12-01

    Pre-weighed packets of Spartina alterniflora and of plastic (polypropylene) twine were placed in a salt marsh pool and recovered on 40 dates spanning 14 months. New packets were placed out regularly to provide a contrast with ageing material. Twelve species of copepods were extracted, counted, and identified. Dry weight and Kjeldahl-nitrogen were determined for Spartina packets. Eight species of copepods, Amphiascus pallidus, Onychocamptus mohammed, Cletocamptus deitersei, Halicyclops sp., Harpacticus chelifer, Mesochra lilljeborgii, Metis jousseaumei and Nitocra sp. were found in higher densities on old grass or plastic packets than on new. The quantity of material was important in that the relative attractiveness of old grass was much lower early in the second year when 7-15% dw and 07% nitrogen remained than early in the first year when over 60% dw and 20% nitrogen remained. Old plastic polypropylene was equally or more attractive than old grass to 7 of 8 species, therefore, nitrogen decline in old grass was not the factor making it less attractive. Once aged, the quantity of substrate was more important than its quality. Apparently, this is due to colonization by microflora or settlement of detritus but these were not studied. The four clear exceptions to these trends were Darcythompsonia fairliensis and Eurytemora affinis which showed highest densities 72% and 50% of the time in new grass, Apocyclops spartinus with 70% in grass and equal numbers between old and new packets and Acartia tonsa a bay calanoid with 82% of highest densities in the water column and only two occurrences out of 40 dates in the packets.

  16. Transgenerational effects alleviate severe fecundity loss during ocean acidification in a ubiquitous planktonic copepod.

    PubMed

    Thor, Peter; Dupont, Sam

    2015-06-01

    Ocean acidification (OA) caused by anthropogenic CO2 emission is projected for thousands of years to come, and significant effects are predicted for many marine organisms. While significant evolutionary responses are expected during such persistent environmental change, most studies consider only short-term effects. Little is known about the transgenerational effects of parental environments or natural selection on the capacity of populations to counter detrimental OA effects. In this study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO2 partial pressures (pCO2 of 400, 900 and 1550 μatm) and grown for two generations at these conditions. Our results show evidence of alleviation of OA effects as a result of transgenerational effects in P. acuspes. Second generation adults showed a 29% decrease in fecundity at 900 μatm CO2 compared to 400 μatm CO2 . This was accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a pCO2 exceeding the natural range experienced by P. acuspes (1550 μatm), fecundity would have decreased by as much as 67% compared to at 400 μatm CO2 as a result of this plasticity. However, transgenerational effects partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900 μatm CO2 . This also relieved the copepods from metabolic stress, and respiration rates were lower than at 900 μatm CO2 . These results highlight the importance of tests for transgenerational effects to avoid overestimation of the effects of OA. PMID:25430823

  17. Cloning and expression of ecdysone receptor (EcR) from the intertidal copepod, Tigriopus japonicus.

    PubMed

    Hwang, Dae-Sik; Lee, Jin-Seon; Lee, Kyun-Woo; Rhee, Jae-Sung; Han, Jeonghoon; Lee, Jehee; Park, Gyung Soo; Lee, Young-Mi; Lee, Jae-Seong

    2010-04-01

    Ecdysteroids are steroid hormones that play an important role in development, growth, molting of larva, and reproduction in the Arthropoda. The effect of ecdysteroids is mediated by its binding to ecdysteroid receptor (EcR). To investigate the role of EcR during development and the effect to environmental stressors on EcR expression in a copepod, we isolated and characterized cDNA and 5'-promoter region of the Tigriopus japonicus EcR (TJ-EcR), and studied mRNA expression pattern. The full-length TJ-EcR cDNA sequence was 1962bp in length and the open reading frame encoded 546 amino acids. The deduced TJ-EcR protein contained well-conserved DNA-binding domain and ligand-binding domain. Phylogenetic analysis revealed that TJ-EcR was clustered with the EcR of other crustaceans. TJ-EcR mRNA was expressed in a developmental stage-specific manner: high in early developmental stages and low in the adult stage. Significantly elevated expression of the TJ-EcR gene in adults was detected at hypersalinity (42ppt) and high temperature (35 degrees C) condition. The 5'-flanking region of TJ-EcR gene contains heat shock protein 70 response elements, implying that the environmental stressors may affect its expression via the stress-sensor. In addition, bisphenol A (100microg/L) repressed TJ-EcR expression. Our results suggest that TJ-EcR could be a biomarker for the monitoring of the impact of environmental stressors in copepods. PMID:20025995

  18. Evidence for ontogenetic feeding strategies in four calanoid copepods in the East Sea (Japan Sea) in summer, revealed by stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Im, Dong-Hoon; Wi, Jin Hee; Suh, Hae-Lip

    2015-09-01

    Deciphering the ontogenetic feeding ecology of copepods is essential to understanding their role in the energy transfer of marine ecosystems. We used stable isotope analysis to examine the ontogenetic feeding strategies of the four coexisting calanoid copepods, Mesocalanus tenuicornis, Metridia pacifica, Calanus sinicus, and Neocalanus plumchrus, in the East Sea (Japan Sea) in summer. Moreover, we used the stable carbon and nitrogen isotope composition of small-sized plankton in three cell size fractions, pico- (< 2 μm), nano- (2-20 μm) and microplankton (20-200 μm), to identify the dietary preference at each developmental stage. The relative carbon masses of pico-, nano- and microplankton were 18, 38, and 44%, respectively, and their δ13C and δ15N values gradually increased with increasing size classes. The ontogenetic trophic position of four copepods were relatively low and ranged from 2.1 to 2.6, indicating that herbivores feed on small-sized phytoplankton, pico- and nanoplankton. Among copepodid stages, the δ13C and δ15N values of M. tenuicornis and C. sinicus differed significantly, while those of M. pacifica and N. plumchrus were not significantly different. In M. tenuicornis, the smallest species among the four copepods examined, the diet preference of CIV for picoplankton changed to nanoplankton in the adult stage. When M. pacifica developed from CIV to adult, the diet preference changed from pico- to microplankton. The proportion of microplankton in the diet of C. sinicus and N. plumchrus increased from CIV to female adult and from CIII to CV, respectively. During the developmental progress in copepodid stages, the smaller copepods significantly changed their dietary preference from pico- to microplankton, while the larger copepods consistently fed on microplankton. We suggest that smaller copepods have an advantage in survival at early copepodid stages compared with larger copepods in summer when microplankton biomass is relatively low.

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

    NASA Astrophysics Data System (ADS)

    Olson, Robert J.; Popp, Brian N.; Graham, Brittany S.; López-Ibarra, Gladis A.; Galván-Magaña, Felipe; Lennert-Cody, Cleridy E.; Bocanegra-Castillo, Noemi; Wallsgrove, Natalie J.; Gier, Elizabeth; Alatorre-Ramírez, Vanessa; Ballance, Lisa T.; Fry, Brian

    2010-07-01

    Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and yellowfin tuna ( Thunnus albacares), and to quantify yellowfin tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ 15N values of several omnivorous copepod species, we examined isotopic spatial relationships among yellowfin tuna and copepods. We found a broad-scale, uniform gradient in δ 15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ 15N values in the white muscle of yellowfin tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ 15N values at the base of the food web, the isotopic difference between these two taxa, “ ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin tuna trophic-position estimates based on their bulk δ 15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore-offshore, east to west gradient in yellowfin tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of yellowfin tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin tuna stomach contents did not show a regular inshore-offshore gradient in trophic position during 2003-2005, but the trophic-position estimates based on both methods had similar scales of variability. We conclude that trophic status of yellowfin tuna increased significantly from east to west over the study area based on the spatial pattern of ΔYFT-COP values and the difference between the δ 15N values of glutamic acid and glycine, “trophic” and “source” amino acids, respectively. These results provide improved depictions of trophic links and biomass flows for food-web models, effective tools to evaluate climate and fishing effects on exploited ecosystems.

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

    PubMed

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

    2014-03-15

    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 10C 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

  1. Association of Vibrio cholerae O1 El Tor and O139 Bengal with the Copepods Acartia tonsa and Eurytemora affinis?

    PubMed Central

    Rawlings, Tonya K.; Ruiz, Gregory M.; Colwell, Rita R.

    2007-01-01

    The association of Vibrio cholerae with zooplankton has been suggested as an important factor in transmission of human epidemic cholera, and the ability to colonize zooplankton surfaces may play a role in the temporal variation and predominance of the two different serogroups (V. cholerae O1 El Tor and O139) in the aquatic environment. To date, interactions between specific serogroups and species of plankton remain poorly understood. Laboratory microcosm experiments were carried out to compare quantitatively the colonization of two copepod species, Acartia tonsa and Eurytemora affinis, by each of the epidemic serogroups. V. cholerae O1 consistently achieved higher abundances than V. cholerae O139 in colonizing adults of each copepod species as well as the multiple life stages of E. affinis. This difference in colonization may be significant in the general predominance of V. cholerae O1 in cholera epidemics in rural Bangladesh where water supplies are taken directly from the environment. PMID:17951440

  2. A new species of copepod (Siphonostomatoida: Caligidae) parasitic on the tiger shark Galeocerdo cuvier (Pron & Lesueur) from Western Australian waters.

    PubMed

    Tang, Danny; Newbound, Dennyse R

    2004-05-01

    A new species of sea-louse (Caligidae, Siphonostomatoida), Caligus oculicola n. sp., is described from the eye surface of the tiger shark Galeocerdo cuvier from off the northwestern coast of Australia. This copepod is distinguished from its congeners by a combination of characters that include: (i) a bifid, dentiform process of the maxillule; (ii) a sternal furca with a box longer than wide and diverging, truncate tines; (iii) terminal spines 1 to 3 on the last segment of leg 1 exopod, each with serrate margins and an accessory process (accessory process on the spines extending beyond the tip of the spine itself); and (iv) a two-segmented exopod of leg 4 with an armature formula of I-0; III. This is the first description of a caligid copepod collected from a shark host in Western Australian waters. The host-parasite relationships between Caligus oculicola and its elasmobranch host are discussed. PMID:15084834

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

    PubMed Central

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

    2012-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Leandro, Srgio Miguel; Morgado, Fernando; Pereira, Fbio; Queiroga, Henrique

    2007-08-01

    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.

  5. Mesoscale structure of copepod assemblages in the coastal transition zone and oceanic waters off central-southern Chile

    NASA Astrophysics Data System (ADS)

    Morales, Carmen E.; Loreto Torreblanca, M.; Hormazabal, Samuel; Correa-Ramrez, Marco; Nuez, Sergio; Hidalgo, Pamela

    2010-03-01

    In the Humboldt Current System, the region off central-southern Chile has relatively high eddy kinetic energy, generating an extensive coastal transition zone (?600 km offshore) in which coastally derived eddies are recurrent features. This energy might promote strong exchanges of water, biogeochemical properties, and plankton between the coastal upwelling band and the adjacent oceanic zone. In this study, the mesoscale structure of epipelagic copepod assemblages and its relationship to environmental variability and the eddy field in the coastal transition zone and oceanic areas off Concepcin (34-39S, 73-84W) were investigated. Zooplankton samples were collected during cruises of opportunity carried out during the 2006 coastal upwelling season and the oceanographic conditions were derived from satellite data on sea surface height, temperature, and chlorophyll a. The use of cluster analyses and indicator species revealed two main copepod assemblages: (i) species with a mainly coastal distribution, the maximum in total abundance being found nearshore and (ii) species with a mainly oceanic distribution (beyond ?500 km from the coast), where a secondary maximum was observed. Both types of assemblages, however, included species widely distributed in the coastal transition zone. An ordination analysis identified sea surface temperature and chlorophyll a as the main factors affecting the distribution of most species and the clustering of stations resembled the distribution of these variables. Some of the large calanoid species that are common in shelf waters were more abundant within nearshore eddies rich in chlorophyll a and other cyclonic eddies far offshore; however, the eddy field alone did not explain the copepod mesoscale distribution. Altogether, the wide distribution of shelf/slope copepod species in this region suggests that physical and biological mechanisms might be acting to extend the productive area of the coastal upwelling zone.

  6. 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)

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

    2012-12-01

    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.

  7. Two new species of parasitic copepods (Crustacea) on two immigrant rabbitfishes (Family Siganidae) from the Red Sea.

    PubMed

    El-Rashidy, H H; Boxshall, G A

    2011-07-01

    Two new species of parasitic copepods, one from each of the families Hatschekiidae and Bomolochidae, are reported from two immigrant species of rabbitfishes (Family Siganidae), both of which originated from the Red Sea but are now established in the Mediterranean. The descriptions of Hatschekia siganicola n. sp. and Nothobomolochus neomediterraneus n. sp. are based on material of both sexes obtained from the gills of Siganus luridus Rppell and S. rivulatus Forsskl, respectively, caught in Egyptian Mediterranean waters off the Alexandrian coast. PMID:21643895

  8. Estuarine calanoid copepod abundance in relation to season, salinity, and land-derived nitrogen loading, Waquoit Bay, MA

    NASA Astrophysics Data System (ADS)

    Lawrence, David; Valiela, Ivan; Tomasky, Gabrielle

    2004-11-01

    Calanoid copepod abundance and distribution were measured by monthly plankton tows from May through November in 1998 and March through August in 1999 in three subestuaries of the Waquoit Bay estuarine system. There was a dramatic seasonal change in the composition of calanoids in Waquoit Bay with a spring community consisting of Acartia hudsonica, Centropages hamatus, and Eurytemora affinis, replaced by Acartia tonsa in the summer. The abundance of A. hudsonica, A. tonsa, and C. hamatus was higher in the saltier reaches of the subestuaries, but the abundance of E. affinis and copepod nauplii was not affected by salinity. Even though different land-derived nitrogen loads created different concentrations of chlorophyll in the water of Waquoit Bay subestuaries, there was no apparent response in the abundance of most calanoid copepods to differences in nitrogen load to the subestuaries. The uncoupling of phytoplankton food from mesozooplankton consumers suggests that other factors such as water residence time, phytoplankton quality and composition, or variations in microzooplankton food play a role in the abundance dynamics of Waquoit Bay calanoid populations.

  9. Towards an internationally harmonized test method for reproductive and developmental effects of endocrine disrupters in marine copepods.

    PubMed

    Kusk, K Ole; Wollenberger, Leah

    2007-02-01

    New and updated methods to detect and characterize endocrine disrupting chemicals (EDCs) are urgently needed for the purpose of environmental risk assessment since these substances are often not detected using existing chronic toxicity tests. Numerous reports on the effects of EDCs on crustacean development and reproduction have been published and the development of life-cycle tests with crustaceans has been prioritized within the OECD work program for endocrine disrupter testing and assessment. As a result, Sweden, and Denmark initiated a proposal for development of a full life-cycle test with marine copepods (Acartia tonsa, Nitocra spinipes, Tisbe battagliai, and Amphiascus tenuiremis). The present paper gives an overview on the endocrine system of crustaceans with special emphasis on development and reproduction, which are targets for endocrine disruption, and reviews available methods for detecting effects on development and reproduction in calanoid and harpacticoid copepods. A draft OECD guideline Copepod Development and Reproduction Test has been developed, and a pre-validation of this draft guideline was completed in 2005. An updated draft guideline, taking into account the results of the pre-validation, is now under validation in an international ring-test, which is running till the end of 2006. PMID:17253162

  10. The metabolic response of marine copepods to environmental warming and ocean acidification in the absence of food

    PubMed Central

    Mayor, Daniel J.; Sommer, Ulf; Cook, Kathryn B.; Viant, Mark R.

    2015-01-01

    Marine copepods are central to the productivity and biogeochemistry of marine ecosystems. Nevertheless, the direct and indirect effects of climate change on their metabolic functioning remain poorly understood. Here, we use metabolomics, the unbiased study of multiple low molecular weight organic metabolites, to examine how the physiology of Calanus spp. is affected by end-of-century global warming and ocean acidification scenarios. We report that the physiological stresses associated with incubation without food over a 5-day period greatly exceed those caused directly by seawater temperature or pH perturbations. This highlights the need to contextualise the results of climate change experiments by comparison to other, naturally occurring stressors such as food deprivation, which is being exacerbated by global warming. Protein and lipid metabolism were up-regulated in the food-deprived animals, with a novel class of taurine-containing lipids and the essential polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid and docosahexaenoic acid, changing significantly over the duration of our experiment. Copepods derive these PUFAs by ingesting diatoms and flagellated microplankton respectively. Climate-driven changes in the productivity, phenology and composition of microplankton communities, and hence the availability of these fatty acids, therefore have the potential to influence the ability of copepods to survive starvation and other environmental stressors. PMID:26364855

  11. The metabolic response of marine copepods to environmental warming and ocean acidification in the absence of food

    NASA Astrophysics Data System (ADS)

    Mayor, Daniel J.; Sommer, Ulf; Cook, Kathryn B.; Viant, Mark R.

    2015-09-01

    Marine copepods are central to the productivity and biogeochemistry of marine ecosystems. Nevertheless, the direct and indirect effects of climate change on their metabolic functioning remain poorly understood. Here, we use metabolomics, the unbiased study of multiple low molecular weight organic metabolites, to examine how the physiology of Calanus spp. is affected by end-of-century global warming and ocean acidification scenarios. We report that the physiological stresses associated with incubation without food over a 5-day period greatly exceed those caused directly by seawater temperature or pH perturbations. This highlights the need to contextualise the results of climate change experiments by comparison to other, naturally occurring stressors such as food deprivation, which is being exacerbated by global warming. Protein and lipid metabolism were up-regulated in the food-deprived animals, with a novel class of taurine-containing lipids and the essential polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid and docosahexaenoic acid, changing significantly over the duration of our experiment. Copepods derive these PUFAs by ingesting diatoms and flagellated microplankton respectively. Climate-driven changes in the productivity, phenology and composition of microplankton communities, and hence the availability of these fatty acids, therefore have the potential to influence the ability of copepods to survive starvation and other environmental stressors.

  12. Detailed surface morphology of the 'lobster louse' copepod, Nicotho astaci, a haematophagous gill parasite of the European lobster, Homarus gammarus.

    PubMed

    Davies, Charlotte E; Thomas, Gethin R; Maffeis, Thierry G G; Wootton, Emma C; Penny, Mark W; Rowley, Andrew F

    2014-10-01

    The ectoparasitic copepod, Nicotho astaci (the 'lobster louse'), infests the gills of the European lobster, Homarus gammarus. There have been limited studies on this haematophagous species; therefore knowledge of this parasite is rudimentary. The current study examines the surface morphology of this parasitic copepod, detached from the host, concentrating on adaptations of the suctorial mouthpart, the oral disc. Cryo-scanning electron microscopy revealed structural adaptations that facilitate attachment of these parasites to the gill filaments of their lobster host. The aperture of the feeding channel, through which host haemolymph is drawn, is only ca. 5?m in diameter. The edge of the oral disc is lined with numerous setae, whilst the surface of the disc is covered with large numbers of small (<1?m in diameter) teeth-like structures, which presumably pierce through, and grip, the cuticle lining of the host's gill. Overall, these structures are thought to provide a 'vacuum seal' to assist in pumping of blood, via peristalsis, into the alimentary canal of the copepod host. PMID:25196471

  13. The metabolic response of marine copepods to environmental warming and ocean acidification in the absence of food.

    PubMed

    Mayor, Daniel J; Sommer, Ulf; Cook, Kathryn B; Viant, Mark R

    2015-01-01

    Marine copepods are central to the productivity and biogeochemistry of marine ecosystems. Nevertheless, the direct and indirect effects of climate change on their metabolic functioning remain poorly understood. Here, we use metabolomics, the unbiased study of multiple low molecular weight organic metabolites, to examine how the physiology of Calanus spp. is affected by end-of-century global warming and ocean acidification scenarios. We report that the physiological stresses associated with incubation without food over a 5-day period greatly exceed those caused directly by seawater temperature or pH perturbations. This highlights the need to contextualise the results of climate change experiments by comparison to other, naturally occurring stressors such as food deprivation, which is being exacerbated by global warming. Protein and lipid metabolism were up-regulated in the food-deprived animals, with a novel class of taurine-containing lipids and the essential polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid and docosahexaenoic acid, changing significantly over the duration of our experiment. Copepods derive these PUFAs by ingesting diatoms and flagellated microplankton respectively. Climate-driven changes in the productivity, phenology and composition of microplankton communities, and hence the availability of these fatty acids, therefore have the potential to influence the ability of copepods to survive starvation and other environmental stressors. PMID:26364855

  14. Genome-wide identification and transcript profile of the whole cathepsin superfamily in the intertidal copepod Tigriopus japonicus.

    PubMed

    Jeong, Chang-Bum; Kim, Bo-Mi; Choi, Hyeon-Jeong; Baek, Inseon; Souissi, Sami; Park, Heum Gi; Lee, Jae-Seong; Rhee, Jae-Sung

    2015-11-01

    Modulation of expression of cathepsins in innate immune response has previously been reported in mollusks and large crustaceans including crabs, lobsters, and shrimps in response to immune challenges. However, similar responses in copepods and the related cathepsin members remain under-investigated. To understand molecular and innate immune responses in the intertidal copepod Tigriopus japonicus, we identified the full spectra of cathepsin members (2 aspartyl proteases, 18 cysteine proteases, and 4 serine proteases) and also analyzed transcriptional expression of cathepsin (Tj-cathepsin) genes in developmental stages, lipopolysaccharide (LPS)- and two Vibrio species-exposed T. japonicus. The transcriptional levels of most Tj-cathepsin genes were highly increased during the molting transition from the nauplius to the copepodid stages. LPS treatment induced innate immune response via significant transcriptional increase of serine cathepsin (e.g., cathepsin As) members with induction of several cysteine cathepsin genes. However, Tj-aspartyl cathepsin E-like and a novel cysteine cathepsin were slightly reduced in response to LPS exposure. Interestingly, Vibrio species showed very low transcriptional sensitivity in the expression of entire cathepsins, while LPS induced several cathepsin gene-involved primitive immune responses in T. japonicus. In this paper, we discuss how whole cathepsin expression profiling can be linked to host defense mechanism to better understand and uncover the underlying mechanism of copepods' innate immunity. PMID:26116442

  15. Mycosporine-like amino acids in freshwater copepods: potential sources and some factors that affect their bioaccumulation.

    PubMed

    Garca, Patricia E; Diguez, Mara C; Ferraro, Marcela A; Zagarese, Horacio E; Prez, Alejandra P

    2010-01-01

    Mycosporine-like amino acids (MAAs) are ubiquitous photoprotective compounds in aquatic environments. MAAs are synthesized by a wide variety of organisms (i.e. bacteria, fungi and algae) and their production is photoinducible by ultraviolet radiation (UVR) (280-400 nm) and/or photosynthetically active radiation (400-750 nm). Most animals however, are unable to synthesize MAAs and must acquire these compounds through their diet or from symbiotic organisms. In this paper, we investigate the possible sources of MAAs and factors (temperature and initial MAA concentration) that may affect their bioaccumulation in freshwater copepods. We found that MAA accumulation may occur even if the copepods are cultured on a MAA-free diet. In addition, we found that the bacteriostatic antibiotic, chloramphenicol, inhibits the bioaccumulation of MAAs. These two pieces of evidence suggest that the source of MAAs in these copepods may be prokaryotic organisms in close association with the animals. The two factors investigated in this study, temperature and initial MAA concentrations, were found to affect the rates at which MAAs are accumulated. Temperature had positive effects on both uptake and elimination rates. On the other hand, the rate of uptake decreased at the highest assayed initial MAA concentration, probably because the concentration of MAAs was already close to saturation. PMID:20003153

  16. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae — can we identify the underlying factors?

    PubMed Central

    van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F.; Kjørsvik, Elin; Hamre, Kristin

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks. PMID:26038712

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

    PubMed

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

    2013-09-01

    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

  18. Herbivorous or omnivorous? On the significance of lipid compositions as trophic markers in Antarctic copepods

    NASA Astrophysics Data System (ADS)

    Graeve, Martin; Hagen, Wilhelm; Kattner, Gerhard

    1994-05-01

    Three dominant Antarctic copepods, Calanoides acutus, Rhincalanus gigas and Metridia gerlachei (copepodite stages V and females), were collected during summer (January/ February) in the southern Weddell Sea south of 70S. Detailed analyses of their lipid and fatty acid/ alcohol compositions were carried out. The trophic positions of these copepods were elucidated by means of the lipid compositions ("marker lipids"). High amounts of wax esters were found in C. acutus (92% of total lipids) and in R. gigas (84-86%). The level of wax esters in M. gerlachei was relatively low (27-42%), while the accumulation of triacylglycerols tended to be higher (19-22%). Characteristic lipid components of C. acutus were the long-chain monounsaturated fatty acids and fatty alcohols 20:1 (n-9) and 22:1 (n-11). These components together with elevated amounts of the 18:4 (n-3) and, to a lesser degree, of the 16:! (n-7) fatty acids, typical of phytoplankton lipids, indicate herbivorous feeding for C. acutus. Other abundant fatty acids were 20:5 (n-3) and 22:6 (n-3). The fatty acid composition of M. gerlachei was characterized by very high amounts of these 22:6 and 20:5 acids. Other important fatty acids were 18:1 (n-9) and 16:0, but only small amounts of 16:1 (n-7) and 18:4 (n-3) occurred. In contrast to C. acutus the fatty alcohols of M. gerlachei consisted almost exclusively of the short-chain components 14:0 and 16:0 M. gerlachei is known as an omnivorous species, which was clearly reflected by its lipid and fatty acid/alcohol pattern. Few data are available on the feeding of R. gigas, but it is usuaally described as an herbivorous small-particle feeder. R. gigas showed fatty acid/alcohol characteristics typical of either C. acutus or M. gerlachei. Higher amounts of the 16:1 (n-7) and 18:4 (n-3) fatty acids suggest herbivorous feeding, whereas the dominance of short-chain alcohols (14:0 and 16:0) resembled the lipid pattern found in the omnivorous M. gerlachei. Hence, the lipid composition of R. gigas showed an intermediate pattern, which implies a tendency towards an opportunistic feeding mode, positioned somewhere between the other two species.

  19. Short-term changes of the mesozooplankton community and copepod gut pigment in the Chukchi Sea in autumn

    NASA Astrophysics Data System (ADS)

    Matsuno, K.; Yamaguchi, A.; Nishino, S.; Inoue, J.; Kikuchi, T.

    2015-03-01

    In the Chukchi Sea, due to the recent drastic reduction of sea-ice during the summer, an increasing formation of atmospheric turbulence has been reported. However, the importance and effects of atmospheric turbulence on the marine ecosystem are not fully understood in this region. To evaluate the effect of atmospheric turbulence on the marine ecosystem, high-frequent sampling (two to four times per day) on the mesozooplankton community and the gut pigment of dominant copepods were made at a fixed station in the Chukchi Sea from 10 to 25 September 2013. During the study period, a strong wind event (SWE) was observed on 18 September. After the SWE, the standing stock of chlorophyll a (chl a) was increased, especially for micro-size (> 10 μm) fractions. Zooplankton abundance ranged 23 610-56 809 ind. m-2 and exhibited no clear changes with SWE. In terms of abundance, calanoid copepods constituted the most dominated taxa (mean: 57%), followed by barnacle larvae (31%). Within the calanoid copepods, small-sized Pseudocalanus spp. (65%) and large-sized Calanus glacialis (30%) dominated. In the population structure of C. glacialis, copepodid stage 5 (C5) dominated, and the mean copepodid stage did not vary with SWE. The dominance of accumulated lipids in C5 and C6 females with immature gonads indicated that they were preparing for seasonal diapause. The gut pigment of C. glacialis C5 was higher at night and was correlated with ambient chl a, and a significant increase was observed after SWE (2.6 vs. 4.5 ng pigment ind.-1). Assuming C : Chl a ratio, the grazing impact by C. glacialis C5 was estimated to be 4.14 mg C m-2 day-1, which corresponded to 0.5-4.6% of the standing stock of micro-size phytoplankton. Compared with the metabolic food requirement, their feeding on phytoplankton accounted for 12.6% of their total food requirement. These facts suggest that C. glacialis could not maintain their population on solely phytoplankton food, and other food sources (i.e., microzooplankton) are important in autumn. As observed for the increase in gut pigment, temporal phytoplankton bloom, which is enhanced by the atmospheric turbulence (SWE) in autumn, may have a positive effect on copepod nutrition. However, because of the relatively long generation length of copepods, a smaller effect was detected for their abundance, population structure, lipid accumulation and gonad maturation within the short-term period (16 days).

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

    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.

  1. Development of acute and chronic sediment bioassays with the harpacticoid copepod Quinquelaophonte sp.

    PubMed

    Stringer, Tristan J; Glover, Chris N; Keesing, Vaughan; Northcott, Grant L; Gaw, Sally; Tremblay, Louis A

    2014-01-01

    Reliable environmentally realistic bioassay methodologies are increasingly needed to assess the effects of environmental pollution. This study describes two estuarine sediment bioassays, one acute (96 h) and one chronic (14 d), with the New Zealand harpacticoid copepod Quinquelaophonte sp. utilising behavioural and reproductive endpoints. Spiked sediments were used to expose Quinquelaophonte sp. to three reference compounds representing important categories of estuarine chemical stressors: zinc (a metal), atrazine (a pesticide), and phenanthrene (a polycyclic aromatic hydrocarbon). Acute-to-chronic ratios (ACR) were used to further characterise species responses. Acute sediment (sandy and low total organic content) 96 h EC50 values for the sublethal inhibition of mobility for zinc, atrazine and phenanthrene were 137, 5.4, and 2.6 g/g, respectively. The chronic EC50 values for inhibition of reproduction (total offspring) were 54.5, 0.0083, and 0.067 g/g for zinc, atrazine, and phenanthrene, respectively. For phenanthrene, a potentially novel mode of action was identified on reproduction. Quinquelaophonte sp. was found to be more sensitive than several other estuarine species indicating choice of test organism is important to characterising the effects of environmentally relevant levels of contamination. The bioassay sediment results demonstrate the sensitivity and suitability of Quinquelaophonte sp. as a tool for the assessment use of estuarine health. PMID:24176293

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

    PubMed

    Avdeev, G V; Sirenko, B I

    2005-01-01

    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

  3. Genotype-by-environment interaction for salinity tolerance in the freshwater-invading copepod Eurytemora affinis.

    PubMed

    Lee, Carol Eunmi; Petersen, Christine H

    2002-01-01

    This study examined the extent of phenotypic plasticity for salinity tolerance and genetic variation in plasticity in the invasive copepod Eurytemora affinis. Euryemora affinis is a species complex inhabiting brackish to hypersaline environments but has invaded freshwater lakes and reservoirs within the past century. Reaction norm experiments were performed on a relatively euryhaline population collected from a brackish lake with fluctuating salinity. Life history traits (hatching rate, survival, and development time) were measured for 20 full-sib clutches that were split and reared at four salinities (fresh, 5, 10, and 27 practical salinity units [PSU]). On average, higher salinities (10 and 27 PSU) were more favorable for larval growth, yielding greater survival and faster development rate. Clutches differed significantly in their response to salinity, with a significant genotype-by-environment interaction for development time. In addition, genetic (clutch) effects were evident in response to low salinity, given that survival in fresh (lake) water was significantly positively correlated with survival at 5 PSU for individual clutches. Clutches raised in fresh water could not survive beyond metamorphosis, suggesting that acclimation to fresh water could not occur in a single generation. Results suggest the importance of natural selection during freshwater invasion events, given the inability of plasticity to generate a freshwater phenotype, and the presence of genetic variation for plasticity upon which natural selection could act. PMID:12324889

  4. Characteristics of suspended solids affect bifenthrin toxicity to the calanoid copepods Eurytemora affinis and Pseudodiaptomus forbesi.

    PubMed

    Parry, Emily; Lesmeister, Sarah; Teh, Swee; Young, Thomas M

    2015-10-01

    Bifenthrin is a pyrethroid pesticide that is highly toxic to aquatic invertebrates. The dissolved concentration is generally thought to be the best predictor of acute toxicity. However, for the filter-feeding calanoid copepods Eurytemora affinis and Pseudodiaptomus forbesi, ingestion of pesticide-bound particles could prove to be another route of exposure. The present study investigated bifenthrin toxicity to E. affinis and P. forbesi in the presence of suspended solids from municipal wastewater effluent and surface water of the San Francisco (CA, USA) Estuary. Suspended solids mitigated the toxicity of total bifenthrin to E. affinis and P. forbesi, but mortality was higher than what would be predicted from dissolved concentrations alone. The results indicate that the toxicity and bioavailability of particle-associated bifenthrin was significantly correlated with counts of 0.5-m to 2-m particle sizes. Potential explanations could include direct ingestion of bifenthrin-bound particles, changes in food consumption and feeding behavior, and physical contact with small particles. The complex interactions between pesticides and particles of different types and sizes demonstrate a need for future ecotoxicological studies to investigate the role of particle sizes on aquatic organisms. PMID:25939857

  5. Diatom/copepod interactions in plankton: the indirect chemical defense of unicellular algae.

    PubMed

    Pohnert, Georg

    2005-06-01

    Numerous coexisting species can be observed in the open oceans. This includes the complex community of the plankton, which comprises all free floating organisms in the sea. Traditionally, nutrient limitation, competition, predation, and abiotic factors have been assumed to shape the community structure in this environment. Only in recent years has the idea arisen that chemical signals and chemical defense can influence species interactions in the plankton as well. Key players at the base of the marine food web are diatoms (unicellular algae with silicified cell walls) and their main predators, the herbivorous copepods. It was assumed that diatoms represent a generally good food source for the grazers but recent work indicates that some species use chemical defenses. Secondary metabolites, released by these algae immediately after wounding, are targeted not against the predators themselves but rather at interfering with their reproductive success. This strategy allows diatoms to reduce the grazer population, thereby influencing the marine food web. This review addresses the chemical ecology of the defensive oxylipins formed by diatoms and the question of how these metabolites can act in such a dilute environment. Aspects of biosynthesis, bioassays, and the possible implications of such a chemical defense for the plankton community structure are also discussed. PMID:15883976

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

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

    PubMed Central

    Kiørboe, Thomas; Jiang, Houshuo

    2013-01-01

    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

  8. Acute and chronic bioassays with New Zealand freshwater copepods using pentachlorophenol

    SciTech Connect

    Willis, K.J.

    1999-11-01

    The suitability for laboratory culture and comparative sensitivity of three species of New Zealand freshwater copepod (Calamoecia lucasi Brady, Boeckella delicata Percival, and Mesocyclops cf. leuckarti Claus) to pentachlorophenol (PCP) was assessed. Acute bioassays used two life stages (nauplii and adults). Acute 48-h lethality tests were conducted at 22 C with laboratory-cultured animals of all species and at varying temperatures with seasonally collected C. lucasi adults. Mean 48-h median lethal concentration values for nauplii ranged from 52 to 227 {micro}g/L PCP for C. lucasi and B. delicata, respectively, and from 106 to 173 {micro}g/L for adult C. Lucasi and M. Leuckarti, respectively. The survival rate in controls was {ge}95% in acute tests, with the exception of C. lucasi nauplii, in which it was 60%. Mean 48-h median lethal concentration values for seasonally collected C. lucasi adults were significantly higher in summer than in all other seasons. Chronic sublethal tests starting with nauplii <24 h old measured time to metamorphosis. Pentachlorophenol delayed metamorphosis in all species. Chronic toxicity values were 14.61, and 104 {micro}g/L PCP for C. lucasi, B. delicata, and M. leuckarti, respectively. The mortality rate in controls was also high in C. lucasi sublethal tests (65%), and of the three species, they were the most difficult to culture.

  9. Functional genomics resources for the North Atlantic copepod, Calanus finmarchicus: EST database and physiological microarray.

    PubMed

    Lenz, Petra H; Unal, Ebru; Hassett, R Patrick; Smith, Christine M; Bucklin, Ann; Christie, Andrew E; Towle, David W

    2012-06-01

    The copepod, Calanus finmarchicus is a keystone species for the North Atlantic. Because of recent changes in the geographic distribution of this species, there are questions as to how this organism responds physiologically to environmental cues. Molecular techniques allow for examination and new understanding of these physiological changes. Here, we describe the development of a microarray for high-throughput studies of the physiological ecology of C. finmarchicus. An EST database was generated for this species using a normalized cDNA library derived from adult and sub-adult individuals. Sequence data were clustered into contigs and annotated using Blastx. Target transcripts were selected, and unique, 50 base-pair, oligomer probes were generated for 995 genes. Blast2GO processing provided detailed information on gene function. The selected targets included broad representation of biological processes, cellular components, and molecular functions. The microarray was tested in two sets of comparisons: adult females maintained at different food concentrations and field-caught sub-adults showing differences in lipid storage. Up-regulated and down-regulated transcripts were identified for both comparisons. Only a small subset of the genes up-regulated in low food individuals were also up-regulated in lipid-poor animals; no overlap was seen between the genes down-regulated in the two comparisons. PMID:22277925

  10. Endosymbiotic copepods may feed on zooxanthellae from their coral host, Pocillopora damicornis

    NASA Astrophysics Data System (ADS)

    Cheng, Y.-R.; Dai, C.-F.

    2010-03-01

    The Xarifiidae is one of the most common families of endosymbiotic copepods that live in close association with scleractinian corals. Previous studies on xarifiids primarily focused on their taxonomy and morphology, while their influence on corals is still unknown. In this study, we collected a total of 1,579 individuals belonging to 6 species of xarifiids from 360 colonies of Pocillopora damicornis at Nanwan Bay, southern Taiwan from July 2007 to May 2008. Furthermore, using optical and electron microscopic observations, we examined the gut contents of Xarifia fissilis, the most abundant species of the Xarifiidae that we collected. We found that the gut of X. fissilis was characterized by a reddish-brown color due to the presence of numerous unicellular algae with diameters of 5-10 μm. TEM observations indicated that the unicellular algae possessed typical characteristics of Symbiodinium including a peripheral chloroplast, stalked pyrenoids, starch sheaths, mesokaryotic nuclei, amphiesmas, an accumulation body, and mitochondria. After starving the isolated X. fissilis in the light and dark (light intensity: 140 μmol photon m-2 s-1; photoperiod: 12 h light/12 h dark) for 2 weeks, fluorescence was clearly visible in its gut and fecal pellets under fluorescent microscopic observations. The cultivation experiment supports the hypothesis that the unicellular algae were beneficial to the survival of X. fissilis under light conditions, possibly through transferring photosynthates to the hosts. These results suggest that X. fissilis may consume and retain unicellular algae for further photosynthesis.

  11. Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic.

    PubMed

    Jónasdóttir, Sigrún Huld; Visser, André W; Richardson, Katherine; Heath, Michael R

    2015-09-29

    Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material ("biological pump") is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal "lipid pump," which is highly efficient at sequestering carbon into the deep ocean. It involves the vertical transport and metabolism of carbon rich lipids by overwintering zooplankton. We show that one species, the copepod Calanus finmarchicus overwintering in the North Atlantic, sequesters an amount of carbon equivalent to the sinking flux of detrital material. The efficiency of the lipid pump derives from a near-complete decoupling between nutrient and carbon cycling—a "lipid shunt," and its direct transport of carbon through the mesopelagic zone to below the permanent thermocline with very little attenuation. Inclusion of the lipid pump almost doubles the previous estimates of deep-ocean carbon sequestration by biological processes in the North Atlantic. PMID:26338976

  12. Parental exposure to elevated pCO2 influences the reproductive success of copepods

    PubMed Central

    Cripps, Gemma; Lindeque, Penelope; Flynn, Kevin

    2014-01-01

    Substantial variations are reported for egg production and hatching rates of copepods exposed to elevated carbon dioxide concentrations (pCO2). One possible explanation, as found in other marine taxa, is that prior parental exposure to elevated pCO2 (and/or decreased pH) affects reproductive performance. Previous studies have adopted two distinct approaches, either (1) expose male and female copepoda to the test pCO2/pH scenarios, or (2) solely expose egg-laying females to the tests. Although the former approach is more realistic, the majority of studies have used the latter approach. Here, we investigated the variation in egg production and hatching success of Acartia tonsa between these two experimental designs, across five different pCO2 concentrations (3856000 atm pCO2). In addition, to determine the effect of pCO2 on the hatching success with no prior parental exposure, eggs produced and fertilized under ambient conditions were also exposed to these pCO2 scenarios. Significant variations were found between experimental designs, with approach (1) resulting in higher impacts; here >20% difference was seen in hatching success between experiments at 1000 atm pCO2 scenarios (2100 year scenario), and >85% at 6000 atm pCO2. This study highlights the potential to misrepresent the reproductive response of a species to elevated pCO2 dependent on parental exposure. PMID:25221371

  13. Biotransformation of petroleum hydrocarbons and microbial communities in seawater with oil dispersions and copepod feces.

    PubMed

    Størdal, Ingvild Fladvad; Olsen, Anders Johny; Jenssen, Bjørn Munro; Netzer, Roman; Altin, Dag; Brakstad, Odd Gunnar

    2015-12-30

    To determine biotransformation of components in crude oil dispersions in the presence of feces from marine copepods, dispersed oil was incubated alone, with the addition of clean or oil-containing feces. We hypothesized that the feces would contribute with nutrients to bacteria, and higher concentrations of oil-degrading bacteria, respectively. Presence of clean feces resulted in higher degradation of aromatic oil compounds, but lower degradation of n-alkanes. Presence of oil-containing feces resulted in higher degradation of n-alkanes. The effect of clean feces on aromatic compounds are suggested to be due to higher concentrations of nutrients in the seawater where aromatic degradation takes place, while the lower degradation of n-alkanes are suggested to be due to a preference by bacteria for feces over these compounds. Large aggregates were observed in oil dispersions with clean feces, which may cause sedimentation of un-weathered lipophilic oil compounds towards the seafloor if formed during oil spills. PMID:26494249

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

    PubMed Central

    Barreto, Felipe S.; Burton, Ronald S.

    2013-01-01

    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

  15. Polychaete-parasitizing copepods from the deep-sea Kuril-Kamchatka Trench (Pacific Ocean), with the description of a new Ophelicola species and comments on the currently known annelidicolous copepods

    NASA Astrophysics Data System (ADS)

    Conradi, Mercedes; Bandera, M. Eugenia; Marin, Ivan; Martin, Daniel

    2015-01-01

    The annelid associated copepods, collectively called annelidicolous, were placed in 21 families. Some genera, such as Ophelicola, are considered phylogenetically isolated and are placed into the order Cyclopoida as incertae sedis. In this paper, we describe Ophelicola kurambia, the second species recorded for the genus and the first for the Pacific Ocean. The single known specimen, a female, was found during the German-Russian deep-sea expedition KuramBio at the deep-sea Kuril-Kamchatka Trench. The new species differs from Ophelicola drachi (known from the Gulf of Biscay, Atlantic Ocean) in being attached to the host through the mandibles instead of maxillae and, specially, in the formula of the antennular armature. The study of the new species contributes to clarify the diagnosis of the genus, which clearly differs from Notomasticola (another incertae sedis genus), and resembles both the most modified clausiids (in the mandibular shape and antennular segmentation) and the clausidiids (in the shape of maxilla). However, it does not contribute to clarify the position of Ophelicola within the order Cyclopoida. The paper includes a list of the known annelidicolous copepods (excluding Monstrilloidae) and summarises the main trends shown in terms of diversity, distribution and relationships. Currently, 168 species of copepods from to 74 genera and 22 families and 7 incertae sedis (excluding Monstrilloida) are known to be involved in 235 parasitic relationships (mostly ectoparasitic) with polychaetes. Host polychaetes include 156 species belonging to 104 genera from 22 families (plus 14 unknown). About 50% of these relationships are known from European waters, mainly from shallow depths.

  16. Impacts of restoration of an uncontrolled phosphogypsum dumpsite on the seasonal distribution of abiotic variables, phytoplankton, copepods, and ciliates in a man-made solar saltern.

    PubMed

    Kobbi-Rebai, Rayda; Annabi-Trabelsi, Neila; Khemakhem, Hajer; Ayadi, Habib; Aleya, Lotfi

    2013-03-01

    The restoration of an uncontrolled phosphogypsum landfill was investigated for its effects on the seasonal distribution of phytoplankton, ciliates, and copepods. Sampling was carried out monthly from September 2007 to August 2008 at four ponds of increasing salinity (A1, 41psu; A5, 46psu; A16, 67psu; and C31, 77psu) in the Sfax solar saltern (southeastern Tunisia). Physicochemical and biological analyses were carried out using standard methods. Results showed drastic reduction of phosphate input and greater diversity of phytoplankton, ciliates, and copepods than before restoration. Pennate diatoms and new ciliates, considered bio-indicators of less-stressed marine ecosystems, proliferated in the A1 pond for the first time after restoration. Copepods appeared to feed on a wide range of prey. Economically, removal of the 1.7 million m(3) of phosphate improved the quality of the site's salt production, enabling the salt company to receive the quality ISO 9001 accreditation. PMID:22628105

  17. Ecotoxicological investigation of the effect of accumulation of PAH and possible impact of dispersant in resting high arctic copepod Calanus hyperboreus.

    PubMed

    Nrregaard, Rasmus Dyrmose; Gustavson, Kim; Mller, Eva Friis; Strand, Jakob; Tairova, Zhanna; Mosbech, Anders

    2015-10-01

    Due to high lipid content and a slow metabolism, there is a higher risk of bioaccumulation of oil compounds in Arctic than in temperate copepods. There is also a concern that the bioavailability of oil compounds is higher when oil is dispersed with dispersants. The purpose of this project was to increase the knowledge on how the use of dispersants on an oil spill may affect the passive uptake of PAHs in resting high arctic copepods using Calanus hyperboreus as a model organism. To evaluate this, resting high arctic C. hyperboreus were caught in Disko Bay at>250 meters depth, November 2013, and subsequent experimental work was initiated immediately after, at nearby Arctic Station at Disko Island Western Greenland. C. hyperboreus females were incubated in phenanthrene (111, 50 and 10 nM), pyrene (57, 28 and 6 nM) and benzo(a) pyrene (10, 5 and 1 nM) for three days in treatments with and without oil (corn oil) and dispersant (AGMA DR372). After exposure, the highest measured concentrations of respectively phenanthrene, pyrene and benzo(a) pyrene in the copepods were 129, 30 and 6 nmol PAH g female(-1). Results showed that with addition of oil and dispersant to the water, the accumulation of PAH was significantly reduced, due to the deposition of the PAHs in the oil phase, decreasing the available PAHs for copepod uptake. While PAH metabolites and a depuration of the PAHs were observed, the copepods still contained PAHs after 77 days of incubation in clean seawater. Differences of treatments with and without oil and dispersant on the egg production were not statistically conclusive, although it is the most likely an effect of the highly variable day-to-day egg production between individual copepods. Equally, although there was an indication that the addition of dispersant and oil increased the mortality rate, there was no statistical difference. PMID:26253790

  18. 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)

    Liu, Guangxing; Xu, Donghui

    2009-12-01

    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.

  19. Laboratory and field efficacy of Pedalium murex and predatory copepod, Mesocyclops longisetus on rural malaria vector, Anopheles culicifacies

    PubMed Central

    Chitra, Thangadurai; Murugan, Kadarkarai; Kumar, Arjunan Naresh; Madhiyazhagan, Pari; Nataraj, Thiyagarajan; Indumathi, Duraisamy; Hwang, Jiang-Shiou

    2013-01-01

    Objective To test the potentiality of the leaf extract of Pedalium murex (P. murex) and predatory copepod Mesocyclops longisetus (M. longisetus) in individual and combination in controlling the rural malarial vector, Anopheles culicifacies (An. culicifacies) in laboratory and field studies. Methods P. murex leaves were collected from in and around Erode, Tamilnadu, India. The active compounds were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus. Laboratory studies on larvicidal and pupicidal effects of methanolic extract of P. murex tested against the rural malarial vector, An. culicifacies were significant. Results Evaluated lethal concentrations (LC50) of P. murex extract were 2.68, 3.60, 4.50, 6.44 and 7.60 mg/L for I, II, III, IV and pupae of An. culicifacies, respectively. Predatory copepod, M. longisetus was examined for their predatory efficacy against the malarial vector, An. culicifacies. M. longisetus showed effective predation on the early instar (47% and 36% on I and II instar) when compared with the later ones (3% and 1% on III and IV instar). Predatory efficacy of M. longisetus was increased (70% and 45% on I and II instar) when the application was along with the P. murex extract. Conclusions Predator survival test showed that the methanolic extract of P. murex is non-toxic to the predatory copepod, M. longisetus. Experiments were also conducted to evaluate the efficacy of methanolic extract of P. murex and M. longisetus in the direct breeding sites (paddy fields) of An. culicifacies. Reduction in larval density was very high and sustained for a long time in combined treatment of P. murex and M. longisetus.

  20. Toxicity of antifouling biocides to the intertidal harpacticoid copepod Tigriopus japonicus (Crustacea, Copepoda): effects of temperature and salinity.

    PubMed

    Kwok, K W H; Leung, K M Y

    2005-01-01

    Intertidal harpacticoid copepods are commonly used in eco-toxicity tests worldwide. They predominately live in mid-high shore rock pools and often experience a wide range of temperature and salinity fluctuation. Most eco-toxicity tests are conducted at fixed temperature and salinity and thus the influence of these environmental factors on chemical toxicity is largely unknown. This study investigated the combined effect of temperature and salinity on the acute toxicity of the copepod Tigriopus japonicus against two common biocides, copper (Cu) and tributyltin (TBT) using a 2 x 3 x 4 factorial design (i.e. two temperatures: 25 and 35 degrees C; three salinities: 15.0 per thousand, 34.5 per thousand and 45.0 per thousand; three levels of the biocide plus a control). Copper sulphate and tributyltin chloride were used as the test chemicals while distilled water and acetone were utilised as solvents for Cu and TBT respectively. 96 h-LC50s of Cu and TBT were 1024 and 0.149 microg l(-1) respectively (at 25 degrees C; 34.5 per thousand) and, based on these results, nominal biocide concentrations of LC0 (i.e. control), LC30, LC50 and LC70 were employed. Analysis of Covariance using 'concentration' as the covariate and both 'temperature' and 'salinity' as fixed factors, showed a significant interaction between temperature and salinity effects for Cu, mortality increasing with temperature but decreasing with elevated salinity. A similar result was revealed for TBT. Both temperature and salinity are, therefore, important factors affecting the results of acute eco-toxicity tests using these marine copepods. We recommend that such eco-toxicity tests should be conducted at a range of environmentally realistic temperature/salinity regimes, as this will enhance the sensitivity of the test and improve the safety margin in line with the precautionary principle. PMID:16291193

  1. Maternal Effects May Act as an Adaptation Mechanism for Copepods Facing pH and Temperature Changes

    PubMed Central

    Vehmaa, Anu; Brutemark, Andreas; Engstrm-st, Jonna

    2012-01-01

    Acidification of the seas, caused by increased dissolution of CO2 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 3C 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 (17C/ambient pH; 17C/low pH; 20C/ambient pH; 20C/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

  2. Spatiotemporal distribution of protozooplankton and copepod nauplii in relation to the occurrence of giant jellyfish in the Yellow Sea

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Xu, Kuidong

    2013-11-01

    The occurrence of the giant jellyfish, Nemopilema nomurai, has been a frequent phenomenon in the Yellow Sea. However, the relationship between the giant jellyfish and protozoa, in particular ciliates, remains largely unknown. We investigated the distribution of nanoflagellates, ciliates, Noctiluca scintillans, and copepod nauplii along the transect 33N in the Yellow Sea in June and August, 2012, during an occurrence of the giant jellyfish, and in October of that year when the jellyfish was absent. The organisms studied were mainly concentrated in the surface waters in summer, while in autumn they were evenly distributed in the water column. Nanoflagellate, ciliate, and copepod nauplii biomasses increased from early June to August along with jellyfish growth, the first two decreased in October, while N. scintillans biomass peaked in early June to 3 571 ?g C/L and decreased in August and October. In summer, ciliate biomass greatly exceeded that of copepod nauplii (4.61-15.04 ?g C/L vs. 0.34-0.89 ?g C/L). Ciliate production was even more important than biomass, ranging from 6.59 to 34.19 ?g C/(Ld) in summer. Our data suggest a tight and positive association among the nano-, micro-, and meso-zooplankton in the study area. Statistical analysis revealed that the abundance and total production of ciliate as well as loricate ciliate biomass were positively correlated with giant jellyfish biomass, indicating a possible predator-prey relationship between ciliates and giant jellyfish. This is in contrast to a previous study, which reported a significant reduction in ciliate standing crops due to the mass occurrence of N. nomurai in summer. Our study indicates that, with its high biomass and, in particular, high production ciliates might support the mass occurrence of giant jellyfish.

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

    PubMed

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

    2014-10-01

    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

  4. Identification of the retinoblastoma (Rb) gene and expression in response to environmental stressors in the intertidal copepod Tigriopus japonicus.

    PubMed

    Kim, Bo-Mi; Jeong, Chang-Bum; Lee, Min Chul; Rhee, Jae-Sung; Lee, Jae-Seong

    2015-12-01

    There have been no reports thus far on the structure or molecular characterization of the retinoblastoma (Rb) gene of aquatic animals. Herein we describe the identification of the Rb gene of the intertidal copepod Tigriopus japonicus. In silico analyses revealed the conserved Rb domains of T. japonicus with those of protostomes. Phylogenetic analysis revealed that orthologs of Rb gene were evolved by an ancient split event in deuterostomes, while only a single Rb gene was conserved in protostomes except for Drosophila. The transcription of the T. japonicus Rb gene continuously increased across the molting transition from nauplius to the copepodid and adult stages, suggesting that it may play a developmental role in the molting process of T. japonicus. Information on Rb's response to environmental stressors, including toxin exposure, is lacking in copepods. To examine the transcriptional response to stressful conditions in laboratory culture conditions, copepods were exposed to UV-B radiation and different concentrations of metals, environmental toxins, and biocides. Transcription of the T. japonicus Rb gene was upregulated in response to about half of the 96h-LD50 of UV-B radiation (12kJ/m(2)) for 48h, while the approximate 96h-LD50 value (24kJ/m(2)) of UV-B and relatively high concentrations of several toxins and biocides induced the downregulation of T. japonicus Rb mRNA expression. Taken together, our findings suggest that the T. japonicus Rb gene is sensitive to environmentally unfavorable conditions that can induce cell cycle alteration. PMID:26474522

  5. Critical body-residues for lethal and sublethal effects of sediment-associated PAH on benthic copepods

    SciTech Connect

    Lotufo, G.R.

    1995-12-31

    Adult females of the meiobenthic copepod Schizopera knabeni were exposed to sediment-associated fluoranthene for 3, 6, 12, 24, 96, and 240 h. Sediment concentrations ranged from 25 to 1,661 nmol (5--336 {micro}g)/gdw and the TOC was 1.5%. Body burden increased to an apparent steady state after only 6 h. Elimination half-lives were 4.6 and 3.2 h in uncontaminated water and sediment, respectively. Toxic effects were only detected after 240 h as increased mortality and decreased offspring production. Significant mortality was observed only at the highest concentration; the LC50 was 1,011 nmol (204 {micro}g)/dgw. In contrast, offspring production was decreased at much lower concentrations, yielding an IC25 value of 148 nmol (30 {micro}g)/dgw. Lethal critical body residue (CBR) was determined as a 10-d LD50 of 15.5 {micro}mol/g dry tissue. By measuring PAH concentrations in the body and eggs of females, CBRs for reproductive output were determined as IC25 values of 2 and 3.1 {micro}mol/gdw, respectively. PAH sublethal effects on feeding rate were also investigated Adult copepods were exposed to {sup 14}C sediment-associated fluoranthene for 24 h were fed {sup 3}H-labeled algae for 3 h. Ingestion rate was significantly decreased at tissue concentrations as low as 1 {micro}mol/gdw and yielded an IC25 value of 0.6 {micro}mol/gdw. Similar findings were obtained using another species of estuarine copepod, Coullana sp. Non-polar narcotic compounds such as PAH cause a nonspecific disturbance of the functioning of cell membrane which results in decreased overall activity. Measurement of CBR associated with decreased feeding is proposed as a direct method to quantify sublethal narcotizing effects of organic compounds.

  6. Effects of sediment-associated phenanthrene and fluoranthene on offspring production, grazing and behavior of an estuarine copepod

    SciTech Connect

    Lotufo, G.R.

    1995-12-31

    Estuarine harpacticoids proved to be excellent toxicity-test organisms due to their ecological importance, small size, short generation time and high fecundity and sensitivity. One acute and three different sublethal sediment-tests were performed using laboratory-cultured Schizopera knabeni, an abundant mud-flat harpacticoid copepod common in US estuaries. All experiments were conducted in the dark and at constant temperature. The sediment TOC was 1.5%. The 96hLC{sub 50} was 524 mg/kg, for phenanthrene and > 2,000 mg/kg for fluoranthene. A strong narcotic effect was observed in the fluoranthene exposures, in which copepods survived exposures of up to 2,100 mg/kg. Effects on offspring production was assessed by exposing either individual mating pairs (male clasping an immature female) or a pool of 20 adult non-ovigerous females and 15 males for 14 days. A significant decrease in the total number of offspring (eggs + juveniles) produced was detected at concentrations as low as 30 mg/kg for both compounds. A stronger reduction was observed on the fraction of the offspring that attained later development stages (copepodite), suggesting that PAHs retard egg hatching and larval development. Effects on grazing activity were detected by feeding starved copepods with {sup 14}C radiolabeled diatoms. A significant decrease in grazing occurred at phenanthrene and fluoranthene concentrations much lower than the 96hLC{sub 50} after a contaminant exposure period of only 48 hours. Behavior experiments performed in an avoidance arena demonstrated that Schizopera displays the ability to detect the presence of PAH in sediment and avoids exposure by selecting and burrowing into uncontaminated over contaminated sediment. This is the first investigation of the effects of PAH single compounds on a meiofaunal organism.

  7. Domestication as a Novel Approach for Improving the Cultivation of Calanoid Copepods: A Case Study with Parvocalanus crassirostris.

    PubMed

    Alajmi, Fahad; Zeng, Chaoshu; Jerry, Dean R

    2015-01-01

    Calanoid copepods are an important food source for most fish larvae. Their role as a natural prey item means that it is important to develop culture technology for copepods to meet the requirements of larvae culture in aquaculture hatcheries. Copepods have been cultured successfully for some time; however, the implications of long-term cultivation or domestication on copepod life history traits have not yet been assessed. Therefore, the aim of this study was to determine if the domesticated and wild populations of Parvocalanus crassirostris are phenotypically or physiologically different. Wild-caught P. crassirostris were compared to a long-held domesticated strain (>2 years) for size of developmental stage, fecundity and lifespan of adult females, culture density, ingestion rates, faecal pellet production and fatty acid profiles. The domesticated strain was significantly different from the wild strain in size (eggs, nauplii, copepodites and adults were larger in the domesticated strain), egg production (112.3 1.8 eggs female(-1) vs. 64.6 3.3 eggs female(-1)) and adult female lifespan (8.8 0.1 days vs., 7.5 0.1 days). At 1, 3 and 5 adults mL(-1), the domesticated strain performed significantly better than the wild strain in egg production (4189.8 61.2, 11224.0 71.7 and 21860.6 103.6 eggs vs. 1319.5 54.3, 2374.5 80.9 and 4933.8 269.5 eggs, respectively) and mean daily mortality rate (5.6% across all densities vs. 22.9 1.6, 29.8 1.2 and 31.3 1.3%, respectively). The domesticated strain had significantly higher ingestion rates than the wild stain (888.4 9.9 ng C l(-1) and 775.3 11.2 ng C l(-1), respectively), while faecal pellet production was not significantly different between strains. Fatty acid profiles indicated higher levels (as % of total fatty acid) of long-chain polyunsaturated fatty acids in the domesticated strain (36.20.4%) than the wild strain (16.10.1%). Overall, this study found that the reproductive capacity and tolerance to the culture environment of the calanoid P. crassirostris have improved significantly due to domestication. PMID:26186526

  8. Domestication as a Novel Approach for Improving the Cultivation of Calanoid Copepods: A Case Study with Parvocalanus crassirostris

    PubMed Central

    Alajmi, Fahad; Zeng, Chaoshu; Jerry, Dean R.

    2015-01-01

    Calanoid copepods are an important food source for most fish larvae. Their role as a natural prey item means that it is important to develop culture technology for copepods to meet the requirements of larvae culture in aquaculture hatcheries. Copepods have been cultured successfully for some time; however, the implications of long-term cultivation or domestication on copepod life history traits have not yet been assessed. Therefore, the aim of this study was to determine if the domesticated and wild populations of Parvocalanus crassirostris are phenotypically or physiologically different. Wild-caught P. crassirostris were compared to a long-held domesticated strain (>2 years) for size of developmental stage, fecundity and lifespan of adult females, culture density, ingestion rates, faecal pellet production and fatty acid profiles. The domesticated strain was significantly different from the wild strain in size (eggs, nauplii, copepodites and adults were larger in the domesticated strain), egg production (112.3 ± 1.8 eggs female-1 vs. 64.6 ± 3.3 eggs female-1) and adult female lifespan (8.8 ± 0.1 days vs., 7.5 ± 0.1 days). At 1, 3 and 5 adults mL-1, the domesticated strain performed significantly better than the wild strain in egg production (4189.8 ± 61.2, 11224.0 ± 71.7 and 21860.6 ± 103.6 eggs vs. 1319.5 ± 54.3, 2374.5 ± 80.9 and 4933.8 ± 269.5 eggs, respectively) and mean daily mortality rate (5.6% across all densities vs. 22.9 ± 1.6, 29.8 ± 1.2 and 31.3 ± 1.3%, respectively). The domesticated strain had significantly higher ingestion rates than the wild stain (888.4 ± 9.9 ng C l-1 and 775.3 ± 11.2 ng C l-1, respectively), while faecal pellet production was not significantly different between strains. Fatty acid profiles indicated higher levels (as % of total fatty acid) of long-chain polyunsaturated fatty acids in the domesticated strain (36.2±0.4%) than the wild strain (16.1±0.1%). Overall, this study found that the reproductive capacity and tolerance to the culture environment of the calanoid P. crassirostris have improved significantly due to domestication. PMID:26186526

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

    SciTech Connect

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

    1998-10-01

    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.

  10. Fatty alcohols in capelin, herring and mackerel oils and muscle lipids: I. Fatty alcohol details linking dietary copepod fat with certain fish depot fats.

    PubMed

    Ratnayake, W N; Ackman, R G

    1979-09-01

    It is shown that the shorter chain (C14-C18) minor fatty alcohols in copepods, fish body lipids, and commercial fish oils are all qualitatively present, and quantitatively similar in proportions to acids found in the depot fats of capelin and mackerel, and in some herring. Although these fatty acids can be formed de novo in fish, copepod alcohols offer an alternative dietary source. Monoethylenic fatty alcohol details, especially for the 22:1 isomers, are reviewed, and the latter are discussed as precursors of the 22:1 fatty acids of fish depot fats, specifically of the dominant 22:1 omega 11 isomer. PMID:491864

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

    PubMed

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

    2012-12-01

    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

  12. Population differentiation in the open sea: insights from the pelagic copepod Pleuromamma xiphias.

    PubMed

    Goetze, Erica

    2011-10-01

    Although a number of recent studies of marine holoplankton have reported significant genetic structure among populations, little is currently known about the biological and oceanographic processes that influence population connectivity in oceanic plankton. In order to examine how depth preferences influence dispersal in oceanic plankton, I characterized the genetic structure of a copepod with diel vertical migration (DVM) (Pleuromamma xiphias), throughout its global distribution, and compared these results to those expected given the interaction of this species' habitat depth with ocean circulation and bathymetry. Mitochondrial COI sequences from 651 individuals from 28 sites in the Indian, Pacific, and Atlantic Oceans revealed highly significant genetic differentiation both within and among ocean basins. Limited dispersal among distinct pelagic provinces seems to have played a major role in population differentiation in this species, with strong genetic breaks observed across known oceanographic fronts or current systems in all three ocean basins. The Indo-West Pacific (IWP) holds a highly distinct genetic population of this species that was sampled in both the western Pacific and eastern Indian Oceans. This suggests that the IWP does not act as a strong barrier to gene flow between basins, as expected, despite the relatively shallow water depth (<200 m) and vertically extensive (>400 m) diel migration of this species. A pattern of isolation by distance was observed in the Indian Ocean with genetic differentiation among samples down to spatial scales of ?800 km, indicating that realized dispersal in P. xiphias occurs over much smaller spatial scales than in previously reported oceanic holoplankton. Given its highly regionalized population genetic structure, P. xiphias may have some capacity to adapt to local oceanographic conditions, and it should not be assumed that populations of this species in distinct pelagic biomes will respond in the same way to shared physical or climatic forcing. PMID:21940778

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

    PubMed

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

    2010-06-01

    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

  14. Alien parasitic copepods in mussels and oysters of the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Elsner, Nikolaus O.; Jacobsen, Sabine; Thieltges, David W.; Reise, Karsten

    2011-09-01

    Molluscan intestinal parasites of the genus Mytilicola, specifically M. intestinalis, were initially introduced into bivalves in the North Sea in the 1930s. It was presumably introduced from the Mediterranean with ship-fouling mussels, then attained epidemic proportions in Mytilus edulis in the 1950s and is now widely established in the North Sea region. Mytilicola orientalis was co-introduced with Pacific oysters to France in the 1970s and in the southern North Sea in the early 1990s. Its main host Crassostrea gigas has massively invaded the Wadden Sea with a concomitant decline in mussels. To explore whether introduced mytilicolid parasites could play a role in the shifting dominance from native mussels to invasive oysters, we analysed 390 mussels and 174 oysters collected around the island of Sylt in the northern Wadden Sea. We show that M. intestinalis has a prevalence >90% and a mean intensity of 4 adult copepods in individual mussels with >50 mm shell length at all sheltered sites. By contrast, none were found in the oysters. However, at one site, we found M. orientalis in C. gigas with a prevalence of 10% and an intensity of 2 per host individual (August 2008). This constitutes the most northern record in Europe for this Pacific parasite until now. Alignments of partial sequences of the mitochondrial cytochrome oxidase I (COI) gene and the nuclear internal transcribed spacers (ITS) and 18S rDNA sequences each show a distinct difference between the two species, which confirms our morphological identification. We suggest that the high parasite load in mussels compared to oysters may benefit the continued expansion of C. gigas in the Wadden Sea.

  15. Habitat usage by the cryptic copepods Pseudocalanus moultoni and P. newmani on Georges Bank (Northwest Atlantic)

    NASA Astrophysics Data System (ADS)

    Bucklin, Ann; McGillicuddy, Dennis J.; Wiebe, Peter H.; Davis, Cabell S.

    2015-12-01

    The cryptic copepod species, Pseudocalanus moultoni and P. newmani, co-occur on Georges Bank and in the Gulf of Maine (Northwest Atlantic); even recent studies have reported results and conclusions based on examination of the combined species. Species-specific PCR (SS-PCR) based on mitochondrial cytochrome oxidase I (COI) sequence divergence was used in this study to discriminate the species. Species-specific descriptions of habitat usage and predicted patterns of transport and retention on Georges Bank were made by mapping distributions and calculating abundances of each species from January to June, 1999 for four vertical strata (0-15 m, 15-40 m, 40-100 m, and 0-100 m) and five regions (Northern Flank, Bank Crest, Northeast Peak, Southern Flank, and Slope Water) identified on the basis of bathymetry and circulation. Patterns of distribution and abundance for the two species during January to June, 1999 were largely consistent with those described based on vertically integrating mapping and analysis for the same period in 1997 by McGillicuddy and Bucklin (2002). The region-specific and depth-stratified analyses allowed further discrimination in habitat usage by the species and confirmed the distinctive patterns for the two species. The observed differences between the species in abundances among the five regions and three depth strata over Georges Bank impact their transport trajectories. The concentration of P. moultoni in deep layers likely explains the higher rates of retention and lower rates of advective loss of this species from the Bank, compared to P. newmani, which may be more subject to wind-driven transport in the surface layer. Accurate identification and discrimination of even closely-related and cryptic species is needed to ensure full understanding and realistic predictions of changes in diversity of zooplankton and the functioning of pelagic ecosystems.

  16. Egg production of a marine planktonic copepod in relation to its food supply: laboratory studies

    SciTech Connect

    Checkley, D.M. Jr.

    1980-05-01

    Egg production by Paracalanus parvus, a particle-grazing copepod, was investigated in relation to its food supply. The concentration of available food (P) and the rates of ingestion (I) and egg production (B) were measured simultaneously at intervals of 6 h to 2 d for periods of 2-10 d. concentration, chemical composition (carbon and nitrogen), and species of phytoplankton were experimental variables. Egg production was related to the food ingested during the previous day. For one food type, I and B were rectilinear functions of P. The average maximum rates of ingestion and egg production were 1.1 ..mu..g N female /sup -1/d/sup -1/ and 53 eggs female /sup -1/d/sup -1/, equivalent to specific rates of 1.5 and 0.37 d/sup -1/. B was proportional to I below a critical ingestion rate, I/sub c/, and independent of I above I/sub c/. For II/sub c/, B.I/sup -1/ declined in terms of both carbon and nitrogen. These results, together with the ratio of C:N in particulate matter in the sea off southern California, suggest that nitrogen (hence protein) potentially limits egg production by adult female Paracalanus and that ingested carbon is used inefficiently.

  17. Predicting the Effects of Coastal Hypoxia on Vital Rates of the Planktonic Copepod Acartia tonsa Dana

    PubMed Central

    Elliott, David T.; Pierson, James J.; Roman, Michael R.

    2013-01-01

    We describe a model predicting the effects of low environmental oxygen on vital rates (egg production, somatic growth, and mortality) of the coastal planktonic copepod Acartia tonsa. Hypoxic conditions can result in respiration rate being directly limited by oxygen availability. We hypothesized that A. tonsa egg production, somatic growth, and ingestion rates would all respond in a similar manner to low oxygen conditions, as a result of oxygen dependent changes in respiration rate. Rate data for A. tonsa egg production, somatic growth, and ingestion under low environmental oxygen were compiled from the literature and from supplementary experiments. The response of these rates to oxygen was compared by converting all to the analogous units in terms of oxygen utilization, which we termed analogous respiration rate. These analogous respiration rates, along with published measurements of respiration rates, were used to parameterize and evaluate the relationship between A. tonsa respiration rate and environmental oxygen. At 18C, our results suggest that A. tonsa experiences sub-lethal effects of hypoxia below an oxygen partial pressure of 8.1 kPa (?3.1 mg L?1?=?2.3 mL L?1). The results of this study can be used to predict the effects of hypoxia on A. tonsa growth and mortality as related to environmental temperature and oxygen partial pressure. Such predictions will be useful as a way to incorporate the effects of coastal hypoxia into population, community, or ecosystem level models that include A. tonsa. This approach can also be used to characterize the effects of hypoxia on other aquatic organisms. PMID:23691134

  18. Microbial colonization of copepod body surfaces and chitin degradation in the sea

    NASA Astrophysics Data System (ADS)

    Kirchner, M.

    1995-03-01

    Next to cellulose, chitin (composed of N-acetyl-D-glucosamine sugar units) is the most frequently occurring biopolymer in nature. Among the most common sources of chitin in the marine environment are copepods and the casings of their fecal pellets. During the mineralization of chitin by microorganisms, which occurs chiefly by means of exoenzymes, nitrogen and carbon are returned to the nutrient cycle. In this study, the microbial colonization of the moults (exuviae), carcasses and fecal pellets of Tisbe holothuriae Humes (Copepoda: Harpacticoida) was examined in the laboratory. Results obtained with DAPI staining indicated that a succession of microorganisms from rodshaped bacteria and cocci to starlike aggregates took place, followed by the yeastlike fungus Aureobasidium pullulans (de Bary) Arnaud. No differences were noted between moults from various developmental stages, from nauplius to adult. The ventral sides and extremities of exuviae and carcasses were more rapidly colonized than other parts of the bodies. The casings of fecal pellets were frequently surrounded by bacteria with fimbriae or slime threads. In situ studies of chitin degradation (practical grade chitin from crustacean shells) with the mesh bag technique showed that about 90% of the original substance was lost after 3 months exposure in seawater at temperatures between 10 and 18C. Chitinase activity was measured in the water at two stations near Helgoland, an island in the North Sea. A higher exoenzymatic activity was found in the rocky intertidal zone, compared to the Station Cable Buoy located between the main and Dne island. These values correspond to the higher bacteria numbers (cfu ml-1) found in the rocky intertidal: 10 to 100 greater than those found at the Cable Buoy Station.

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

    NASA Astrophysics Data System (ADS)

    Cowles, Timothy J.; Fessenden, Lynne M.

    1995-04-01

    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.

  20. Oil droplet ingestion and oil fouling in the copepod Calanus finmarchicus exposed to mechanically and chemically dispersed crude oil.

    PubMed

    Nordtug, Trond; Olsen, Anders J; Salaberria, Iurgi; verjordet, Ida B; Altin, Dag; Strdal, Ingvild F; Hansen, Bjrn Henrik

    2015-08-01

    The rates of ingestion of oil microdroplets and oil fouling were investigated in the zooplankton filter-feeder Calanus finmarchicus (Gunnerus, 1770) at 3 concentrations of oil dispersions ranging from 0.25 mg/L to 5.6 mg/L. To compare responses to mechanically and chemically dispersed oil, the copepods were exposed to comparable dispersions of micron-sized oil droplets made with and without the use of a chemical dispersant (similar oil droplet size range and oil concentrations) together with a constant supply of microalgae for a period of 4 d. The filtration rates as well as accumulation of oil droplets decreased with increasing exposure concentration. Thus the estimated total amount of oil associated with the copepod biomass for the 2 lowest exposures in the range 11 mL/kg to 17 mL/kg was significantly higher than the approximately 6 mL/kg found in the highest exposure. For the 2 lowest concentrations the filtration rates were significantly higher in the presence of chemical dispersant. Furthermore, a significant increase in the amount of accumulated oil in the presence of dispersant was observed in the low exposure group. PMID:25855587

  1. Factors influencing the distribution and abundance of diaptomid copepods in high elevation lakes in the Pacific Northwest, USA

    USGS Publications Warehouse

    Liss, W.J.; Larson, Gary L.; Deimling, E.; Ganio, L.; Hoffman, Robert L.; Lomnicky, G.A.

    1998-01-01

    We investigated the impact of abiotic factors and trout density on distribution and abundance of diaptomid copepods in high-elevation lakes in North Cascades National Park Service Complex (NOCA), Washington, USA. The most common large diaptomid, D. kenai (mean length = 1.88 mm), was able to persist over a wide range of abiotic factors, but the small herbivorous diaptomid, D. tyrrelli (mean length = 1.18 mm), was restricted to shallow lakes (maximum depth 250 fish ha-1) than in fishless lakes, in deep lakes with reproducing trout, or in lakes where trout do not reproduce and are 0periodically stocked with fry at low densities (average 179 fry a-1). In lakes where chemical conditions were suitable for D. tyrrelli, the small diaptomid was often abundant when trout density was high and large diaptomids were either absent or in low abundance. Our research suggests that trout density, nutrient concentration, and lake depth influence the abundance of diaptomid copepods in high lakes in NOCA.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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.

  4. Altered grazing patterns in an experimental copepod-alga ecosystem exposed to naphthalene and Kuwait crude oil

    SciTech Connect

    Vandermeulen, J.H.

    1986-02-01

    The authors became interested in the potential disruption of predator-prey relationships after they observed that naphthalene, as well as a number of oils, changed the swimming behavior of the unicellular flagellate alga Pavlova lutheri (formerly Monochrysis lutheri). Reasoning that alterations in the motility of a prey species would render it more susceptible to predation, the authors examined the hydrocarbon-induced changes in predation success in a simple two-member prey-predator system consisting only of P. lutheri and the marine copepod Calanus finmarchicus. The organisms were exposed, together, to low concentrations of either naphthalene or Kuwait crude oil dissolved in seawater, and the feeding efficiency of the copepods under these conditions was measured by counting the survival of algal cells. Naphthalene was chosen because it is a relatively simple toxic aromatic hydrocarbon, common to all crude oils and most refined products and their aqueous extracts. Kuwait crude oil was used as a representative oil mixture more commonly encountered under spillage conditions.

  5. Dietary Carotenoids Regulate Astaxanthin Content of Copepods and Modulate Their Susceptibility to UV Light and Copper Toxicity

    PubMed Central

    Caramujo, Maria-José; de Carvalho, Carla C. C. R.; Silva, Soraya J.; Carman, Kevin R.

    2012-01-01

    High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal). Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC50 values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers. PMID:22822352

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

    NASA Astrophysics Data System (ADS)

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

    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.

  7. Feeding strategies of tropical and subtropical calanoid copepods throughout the eastern Atlantic Ocean - Latitudinal and bathymetric aspects

    NASA Astrophysics Data System (ADS)

    Bode, Maya; Hagen, Wilhelm; Schukat, Anna; Teuber, Lena; Fonseca-Batista, Debany; Dehairs, Frank; Auel, Holger

    2015-11-01

    The majority of global ocean production and total export production is attributed to oligotrophic oceanic regions due to their vast regional expanse. However, energy transfers, food-web structures and trophic relationships in these areas remain largely unknown. Regional and vertical inter- and intra-specific differences in trophic interactions and dietary preferences of calanoid copepods were investigated in four different regions in the open eastern Atlantic Ocean (38°N to 21°S) in October/November 2012 using a combination of fatty acid (FA) and stable isotope (SI) analyses. Mean carnivory indices (CI) based on FA trophic markers generally agreed with trophic positions (TP) derived from δ15N analysis. Most copepods were classified as omnivorous (CI ∼0.5, TP 1.8 to ∼2.5) or carnivorous (CI ⩾ 0.7, TP ⩾ 2.9). Herbivorous copepods showed typical CIs of ⩽0.3. Geographical differences in δ15N values of epi- (200-0 m) to mesopelagic (1000-200 m) copepods reflected corresponding spatial differences in baseline δ15N of particulate organic matter from the upper 100 m. In contrast, species restricted to lower meso- and bathypelagic (2000-1000 m) layers did not show this regional trend. FA compositions were species-specific without distinct intra-specific vertical or spatial variations. Differences were only observed in the southernmost region influenced by the highly productive Benguela Current. Apparently, food availability and dietary composition were widely homogeneous throughout the mesotrophic oceanic regions of the tropical and subtropical Atlantic. Four major species clusters were identified by principal component analysis based on FA compositions. Vertically migrating species clustered with epi- to mesopelagic, non-migrating species, of which only Neocalanus gracilis was moderately enriched in lipids with 16% of dry mass (DM) and stored wax esters (WE) with 37% of total lipid (TL). All other species of this cluster had low lipid contents (<10% DM) without WE. Of these, the tropical epipelagic Undinula vulgaris showed highest portions of bacterial markers. Rhincalanus cornutus, R. nasutus and Calanoides carinatus formed three separate clusters with species-specific lipid profiles, high lipid contents (⩾41% DM), mainly accumulated as WE (⩾79% TL). C. carinatus and R. nasutus were primarily herbivorous with almost no bacterial input. Despite deviating feeding strategies, R. nasutus clustered with deep-dwelling, carnivorous species, which had high amounts of lipids (⩾37% DM) and WE (⩾54% TL). Tropical and subtropical calanoid copepods exhibited a wide variety of life strategies, characterized by specialized feeding. This allows them, together with vertical habitat partitioning, to maintain high abundance and diversity in tropical oligotrophic open oceans, where they play an essential role in the energy flux and carbon cycling.

  8. ACUTE TOXICITY OF FIVE SEDIMENT-ASSOCIATED METALS, INDIVIDUALLY AND IN A MIXTURE, TO THE ESTUARINE MEIOBENTHIC HARPACTICOID COPEPOD AMPHIASCUS TENUIREMIS. (R825279)

    EPA Science Inventory

    Abstract

    The acute effects of many individual, seawater-solubilized metals on meiobenthic copepods and nematodes are well known. In sediments, however, metals most often occur as mixtures, and it is not known whether such mixtures exhibit simple additive toxicity to me...

  9. Copepod biomass, size composition and production in the Southern Benguela: Spatio-temporal patterns of variation, and comparison with other eastern boundary upwelling systems

    NASA Astrophysics Data System (ADS)

    Huggett, Jenny; Verheye, Hans; Escribano, Rubn; Fairweather, Tracey

    2009-12-01

    Zooplankton sampling has been conducted biannually off the west and south-west coasts of South Africa since 1988, as part of the pelagic fish stock assessment cruises covering the continental shelf (0-200 m). Previously established relationships between body mass and growth rate were used to derive copepod production. Mean copepod biomass and annual production in the Southern Benguela between 1988 and 2003 were 2.1 g C m -2 and 134.4 g C m -2 yr -1, respectively. Biomass and production were higher during summer in four latitudinal areas, but seasonal variability was only significant for the central West Coast. This area, lying downstream from the Cape Columbine upwelling cell, supported the highest levels of copepod biomass (3.1 g C m -2) and production (545 g C m -2 d -1). Production during winter, when upwelling is minimal, contributed over one third of annual production in all four areas. Copepod biomass, daily production and size composition varied with latitude, season and year, and there were no consistent trends in interannual variability over the study period. Although biomass in the four major EBUS was of the same magnitude (usually <5 g C m -2), annual production estimates are an order of magnitude greater than those made four decades ago, with highest values for the Southern Benguela.

  10. First insights into genus level diversity and biogeography of deep sea benthopelagic calanoid copepods in the South Atlantic and Southern Ocean

    NASA Astrophysics Data System (ADS)

    Renz, Jasmin; Markhaseva, Elena L.

    2015-11-01

    Calanoid copepods constitute the most numerous organisms not only in the pelagic realm, but also in the benthic boundary layer, which gives them an important role in the turnover of organic matter in the benthopelagic habitat. During seven expeditions to the South Atlantic and Southern Ocean, the diversity and biogeography of deep-sea benthopelagic calanoid copepods were studied. The communities of calanoids living in the vicinity of the seabed were characterized by high diversity comparable to many pelagic habitats, but low abundance of individuals. Members of the taxon Clausocalanoidea dominated the communities, and within this taxon most individuals belonged to detritivore calanoids characterized by sensory setae on the second maxillae or aetideid copepods. 73% of all genera classified as obligate or predominantly benthopelagic copepods detected during these expeditions were new to science and a vast number of genera and species have been described since then. Comparing the communities of calanoid genera between different regions, the assemblages in the Southern Ocean differed significantly from the Southeast and Southwest Atlantic. A latitudinal diversity gradient could be observed, with highest numbers of genera in the Southwest Atlantic and low numbers at stations in the Southern Ocean. Reviewing the literature, endemism for benthopelagic calanoids appeared to be low on a latitudinal range caused by connectivity in benthopelagic habitats through spreading water masses. However, considering the habitats structuring the water column vertically, a high number of genera are endemic in the benthopelagial and specialized to living within the vicinity of the seabed.

  11. Response of microzooplankton (protists and small copepods) to an iron-induced phytoplankton bloom in the Southern Ocean (EisenEx)

    NASA Astrophysics Data System (ADS)

    Henjes, Joachim; Assmy, Philipp; Klaas, Christine; Verity, Peter; Smetacek, Victor

    2007-03-01

    The dynamics, composition and grazing impact of microzooplankton were studied during the in situ iron fertilisation experiment EisenEx in the Antarctic Polar Frontal Zone in austral spring (November 2000). During the 21 day experiment, protozooplankton and small metazooplankton were sampled from the mixed layer inside and outside the patch using Niskin bottles. Aplastidic dinoflagellates increased threefold in abundance and biomass in the first 10 days of the experiment, but decreased thereafter to values twofold higher than pre-fertilisation values. The decline after day 10 is attributed to increasing grazing pressure by copepods. They also constrained ciliate abundances and biomass which were higher inside the fertilised patch than outside but highly variable. Copepod nauplii abundance remained stable whereas biomass doubled. Numbers of copepodites and adults of small copepod species (<1.5 mm) increased threefold inside the patch, but doubled in surrounding waters. Grazing rates estimated using the dilution method suggest that microzooplankton grazing constrained pico- and nanoplankton populations, but species capable of feeding on large diatoms (dinoflagellates and small copepods including possibly nauplii) were selectively predated by the metazoan community. Thus, iron fertilisation of a developing spring phytoplankton assemblage resulted in a trophic cascade which favoured dominance of the bloom by large diatoms.

  12. Influence of water temperature, salinity, and pH on survival and growth of toxigenic Vibrio cholerae serovar 01 associated with live copepods in laboratory microcosms.

    PubMed Central

    Huq, A; West, P A; Small, E B; Huq, M I; Colwell, R R

    1984-01-01

    The influence of water temperature, salinity, and pH on the multiplication of toxigenic Vibrio cholerae serovar O1 cells and their attachment to live planktonic crustaceans, i.e., copepods, was investigated by using laboratory microcosms. By increasing water temperatures up to 30 degrees C, a pronounced effect on the multiplication of V. cholerae was demonstrated, as was attachment of the cells to live copepods. These were measured by culturable counts on agar plates and direct observation by scanning electron microscopy, respectively. Of the three salinities examined (5, 10, and 15%), maximum growth of V. cholerae and attachment to copepods occurred at 15%. An alkaline pH (8.5) was optimal both for attachment and multiplication of V. cholerae, as compared with pH 6.5 and 7.5. It is concluded that conditions affecting attachment of V. cholerae serovar O1 to live copepods observed under laboratory conditions may also occur in the natural estuarine environment and, thereby, are significant in the epidemiology of cholera. Images PMID:6486784

  13. Acute and chronic toxicity study of the water accommodated fraction (WAF), chemically enhanced WAF (CEWAF) of crude oil and dispersant in the rock pool copepod Tigriopus japonicus.

    PubMed

    Lee, Kyun-Woo; Shim, Won Joon; Yim, Un Hyuk; Kang, Jung-Hoon

    2013-08-01

    We determined the toxicity of the water accommodated hydrocarbon fraction (WAF), two chemically enhanced WAFs (CEWAFs; CEWAF-C, Crude oil+Corexit 9500 and CEWAF-H, Crude oil+Hiclean) of crude oil and two dispersants (Corexit 9500 and Hiclean) to the rock pool copepod Tigriopus japonicus. In the acute toxicity test, Corexit 9500 was the most toxic of all the chemicals studied. The nauplius stage of T. japonicus was more susceptible to the toxic chemicals studied than the adult female. The toxicity data using the nauplius stage was then considered as baseline to determine the spiking concentration of chemicals for chronic toxicity tests on the copepod. As the endpoints in the chronic toxicity test, survival, sex ratio, developmental time and fecundity of the copepod were used. All chemicals used in this study resulted in increased toxicity in the F1 generation. The lowest-observed-adverse-effect (LOAE) concentrations of WAF, CEWAF-H, CEWAF-C, Hiclean and Corexit 9500 were observed to be 50%, 10%, 0.1%, 1% and 1%, respectively. The results in present study imply that copepods in marine may be negatively influenced by spilled oil and dispersant. PMID:23466279

  14. EFFECT OF SALINITY VARIATION AND PESTICIDE EXPOSURE ON AN ESTUARINE HARPACTICOID COPEPOD, MICROARTHRIDION LITTORALE (POPPE), IN THE SOUTHEASTERN US. (R827397)

    EPA Science Inventory

    The harpacticoid copepod Microarthridion littorale (Poppe) was tested for interaction effects between salinity change and acute pesticide exposure on the survival and genotypic composition of a South Carolina population. Previous data suggested a significant link betwee...

  15. Extensive genetic diversity and endemism across the global range of the oceanic copepod Pleuromamma abdominalis

    NASA Astrophysics Data System (ADS)

    Hirai, Junya; Tsuda, Atsushi; Goetze, Erica

    2015-11-01

    Many oceanic zooplankton species have been described as cosmopolitan in distribution; however, recent molecular work has detected species complexity with highly divergent genetic lineages within several of these taxa. To further resolve the species complexity within these ecologically-important and widespread species, we performed both molecular and morphological analyses of the oceanic copepod Pleuromamma abdominalis using a comprehensive collection of material from 944 individuals collected at 46 sites across the global ocean. Phylogenetic analyses of mitochondrial cytochrome oxidase subunit I (mtCOI) sequences detected eighteen divergent evolutionary lineages within P. abdominalis, with an additional four singleton specimens that were also genetically divergent. Two phylogenetically distinct groups, PLAB1 and PLAB2, were supported by concordant sequence variation in the nuclear large subunit ribosomal RNA gene (nLSU). Within PLAB1, two mtCOI clades, 1a-1 and 1b-1 were observed, and each clade contained geographically distinct sub-clades 1a-2 and 1b-2. PLAB2 was composed of sixteen well-supported mtCOI clades (2a-2p) as well as four singletons. High genetic divergence among the mtCOI lineages within both PLAB1 and PLAB2, ranging between 9.2-11.2% and 4.3-18.9% K2P distances respectively, suggests the presence of additional species within these groups. Significant differences were observed in the presence and shape of antennule spines of adult females between sympatric clades with genetic distances greater than 5.7-7.0% (K2P). The biogeographic distributions of mtCOI clades indicated greater specialization to particular oceanographic provinces than observed in the nominal species P. abdominalis, with mtCOI clades ranging from antitropical in subtropical waters of all three ocean basins (Atlantic, Pacific and Indian; clade 1b-1 and 2a) to taxa that are endemic to a particular ocean region, for example restricted to equatorial waters of the Atlantic Ocean (clade 1b-2 and 2b). We hypothesize that many of these mtCOI clades are likely distinct, and currently undescribed species. The well-known high dominance of P. abdominalis across a range of pelagic habitats may occur as a spatial composite of genetically-distinct species with more restricted distributions and greater ecological specialization to particular marine habitats than was previously recognized.

  16. 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

    2011-01-01

    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

  17. No evidence for induction or selection of mutant sodium channel expression in the copepod Acartia husdsonica challenged with the toxic dinoflagellate Alexandrium fundyense.

    PubMed

    Finiguerra, Michael; Avery, David E; Dam, Hans G

    2014-09-01

    Some species in the dinoflagellate genus Alexandrium spp. produce a suite of neurotoxins that block sodium channels, known as paralytic shellfish toxins (PST), which have deleterious effects on grazers. Populations of the ubiquitous copepod grazer Acartia hudsonica that have co-occurred with toxic Alexandrium spp. are better adapted than nave populations. The mechanism of adaptation is currently unknown. We hypothesized that a mutation in the sodium channel could account for the grazer adaptation. We tested two hypotheses: (1) Expression of the mutant sodium channel could be induced by exposure to toxic Alexandrium fundyense; (2) in the absence of induction, selection exerted by toxic A. fundyense would favor copepods that predominantly express the mutant isoform. In the copepod A. hudsonica, both isoforms are expressed in all individuals in varying proportions. Thus, in addition to comparing expression ratios of wild-type to mutant isoforms for individual copepods, we also partitioned copepods into three groups: those that predominantly express the mutant (PMI) isoform, the wild-type (PWI) isoform, or both isoforms approximately equally (EI). There were no differences in isoform expression between individuals that were fed toxic and nontoxic food after three and 6 days; induction of mutant isoform expression did not occur. Furthermore, the hypothesis that mutant isoform expression responds to toxic food was also rejected. That is, no consistent evidence showed that the wild-type to mutant isoform ratios decreased, or that the relative proportion of PMI individuals increased, due to the consumption of toxic food over four generations. However, in the selected line that was continuously exposed to toxic food sources, egg production rate increased, which suggested that adaptation occurred but was unrelated to sodium channel isoform expression. PMID:25535562

  18. No evidence for induction or selection of mutant sodium channel expression in the copepod Acartia husdsonica challenged with the toxic dinoflagellate Alexandrium fundyense

    PubMed Central

    Finiguerra, Michael; Avery, David E; Dam, Hans G

    2014-01-01

    Some species in the dinoflagellate genus Alexandrium spp. produce a suite of neurotoxins that block sodium channels, known as paralytic shellfish toxins (PST), which have deleterious effects on grazers. Populations of the ubiquitous copepod grazer Acartia hudsonica that have co-occurred with toxic Alexandrium spp. are better adapted than nave populations. The mechanism of adaptation is currently unknown. We hypothesized that a mutation in the sodium channel could account for the grazer adaptation. We tested two hypotheses: (1) Expression of the mutant sodium channel could be induced by exposure to toxic Alexandrium fundyense; (2) in the absence of induction, selection exerted by toxic A. fundyense would favor copepods that predominantly express the mutant isoform. In the copepod A. hudsonica, both isoforms are expressed in all individuals in varying proportions. Thus, in addition to comparing expression ratios of wild-type to mutant isoforms for individual copepods, we also partitioned copepods into three groups: those that predominantly express the mutant (PMI) isoform, the wild-type (PWI) isoform, or both isoforms approximately equally (EI). There were no differences in isoform expression between individuals that were fed toxic and nontoxic food after three and 6 days; induction of mutant isoform expression did not occur. Furthermore, the hypothesis that mutant isoform expression responds to toxic food was also rejected. That is, no consistent evidence showed that the wild-type to mutant isoform ratios decreased, or that the relative proportion of PMI individuals increased, due to the consumption of toxic food over four generations. However, in the selected line that was continuously exposed to toxic food sources, egg production rate increased, which suggested that adaptation occurred but was unrelated to sodium channel isoform expression. PMID:25535562

  19. Toxicity effect of Delonix elata (Yellow Gulmohr) and predatory efficiency of Copepod, Mesocyclops aspericornis for the control of dengue vector, Aedes aegypti

    PubMed Central

    Vasugi, Chellamuthu; Kamalakannan, Siva; Murugan, Kadarkarai

    2013-01-01

    Objective To evaluate the toxicity, predatory efficiency of Delonix elata (D. elata) and Mesocyclops aspericornis (M. aspericornis) against dengue vector, Aedes aegypti (Ae. aegypti). Methods A mosquitocidal bioassay was conducted at different concentration of plant extract followed by WHO standard method. The probit analysis of each tested concentration and control were observed by using software SPSS 11 version package. The each tested concentration variable was assessed by DMRT method. The predatory efficiency of copepod was followed by Deo et al., 1988. The predator, M. aspericornis was observed for mortality, abnormalities, survival and swimming activity after 24 h treatment of plant and also predation on the mosquito larvae were observed. Results D. elata were tested for biological activity against the larvae, and pupae of Ae. aegypti. Significant mortality effects were observed in each life stage. The percentage of mortality was 100% in first and second instars whereas 96%, 92% in third and fourth instars. Fitted probit-mortality curves for larvae indicated the median and 90% lethal concentrations of D. elata for instars 1-4 to be 4.91 (8.13), 5.16 (8.44), 5.95 (7.76) and 6.87 (11.23), respectively. The results indicate that leaf extract exhibits significant biological activity against life stages. The present study revealed that D. elata is potentially important in the control of Ae. aegypti. Similar studies were conducted for predatory efficiency of Copepod, M. aspericornis against mosquito vector Ae. Aegypti. This study reported that the predatory copepod fed on 39% and 25% in I and III instar larvae of mosquito and in combined treatment of D. elata and copepod maximum control of mosquito larval states and at 83%, 80%, 75% and 53% in I, II, III and IV instars, respectively. Conclusions The combined action of plant extract and predatory copepod to effectively control mosquito population and reduce the dengue transmitting diseases.

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

    NASA Astrophysics Data System (ADS)

    Ji, Rubao; Ashjian, Carin J.; Campbell, Robert G.; Chen, Changsheng; Gao, Guoping; Davis, Cabell S.; Cowles, Geoffrey W.; Beardsley, Robert C.

    2012-04-01

    Calanus spp. copepods play a key role in the Arctic pelagic ecosystem. Among four congeneric species of Calanus found in the Arctic Ocean and its marginal seas, two are expatriates in the Arctic (Calanus finmarchicus and Calanus marshallae) and two are endemic (Calanus glacialis and Calanus hyperboreus). The biogeography of these species likely is controlled by the interactions of their life history traits and physical environment. A mechanistic understanding of these interactions is critical to predicting their future responses to a warming environment. Using a 3-D individual-based model that incorporates temperature-dependent and, for some cases, food-dependent development rates, we show that (1) C. finmarchicus and C. marshallae are unable to penetrate, survive, and colonize the Arctic Ocean under present conditions of temperature, food availability, and length of the growth season, mainly due to insufficient time to reach their diapausing stage and slow transport of the copepods into the Arctic Ocean during the growing season or even during the following winter at the depths the copepods are believed to diapause. (2) For the two endemic species, the model suggests that their capability of diapausing at earlier copepodite stages and utilizing ice-algae as a food source (thus prolonging the growth season length) contribute to the population sustainability in the Arctic Ocean. (3) The inability of C. hyperboreus to attain their first diapause stage in the central Arctic, as demonstrated by the model, suggests that the central Arctic population may be advected from the surrounding shelf regions along with multi-year successive development and diapausing, and/or our current estimation of the growth parameters and the growth season length (based on empirical assessment or literature) needs to be further evaluated. Increasing the length of the growth season or increasing water temperature by 2 C, and therefore increasing development rates, greatly increased the area of the central Arctic in which the Arctic endemics could reach diapause but had little effect on the regions of successful diapause for the expatriate species.

  1. Qualitative use of Dynamic Energy Budget theory in ecotoxicology. Case study on oil contamination and Arctic copepods

    NASA Astrophysics Data System (ADS)

    Klok, Chris; Hjorth, Morten; Dahllf, Ingela

    2012-10-01

    The Dynamic Energy Budget (DEB) theory provides a logic and consistent framework to evaluate ecotoxicological test results. Currently this framework is not regularly applied in ecotoxicology given perceived complexity and data needs. However, even in the case of low data availability the DEB theory is already useful. In this paper we apply the DEB theory to evaluate the results in three previously published papers on the effects of PAHs on Arctic copepods. Since these results do not allow for a quantitative application we used DEB qualitatively. The ecotoxicological results were thereby set in a wider ecological context and we found a logical explanation for an unexpected decline in hatching success described in one of these papers. Moreover, the DEB evaluation helped to derive relevant ecological questions that can guide future experimental work on this subject.

  2. A new genus and species of hatschekiid copepod (Siphonostomatoida) from groupers (Actinopterygii: Serranidae) collected off the Ryukyu Archipelago, Japan.

    PubMed

    Uyeno, Daisuke

    2013-01-01

    A new genus and species of copepod, Mihbaicola sakamakii n. g., n. sp., belonging to the siphonostomatoid family Hatschekiidae, is described based on the females collected from inside the tissue of the branchiostegal membrane in three species of the groupers, Epinephelus fasciatus (Forsskl) (type-host), E. merra Bloch and Cephalopholis leopardus (Lacpde), collected off Okinawa-jima Island and Iriomote-jima Island, Ryukyu Archipelago, North Pacific Ocean. The new genus can be distinguished from other hatschekiid genera by a combination of the following characters in the female: the head is composed of the cephalosome and the pedigerous somite; the cephalothorax is expanded into a pair of posteroventral lobes carrying leg 1; legs 1 and 2 are biramous and composed of the protopod and both rami are 2-segmented; leg 3 is absent; and leg 4 is represented by a rounded lobe with a chitinous pointed apical process. PMID:23263944

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

    PubMed Central

    2013-01-01

    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

  4. Effects of UV radiation on hatching, lipid peroxidation, and fatty acid composition in the copepod Paracyclopina nana.

    PubMed

    Won, Eun-Ji; Lee, Yeonjung; Han, Jeonghoon; Hwang, Un-Ki; Shin, Kyung-Hoon; Park, Heum Gi; Lee, Jae-Seong

    2014-09-01

    To evaluate the effects of UV radiation on the reproductive physiology and macromolecules in marine zooplankton, several doses of UV radiation were used to treat the copepod Paracyclopina nana, and we analyzed in vivo endpoints of their life cycle such as mortality and reproductive parameters with in vitro biochemical biomarkers such as reactive oxygen species (ROS), the modulated enzyme activity of glutathione S-transferase (GST) and superoxide dismutase (SOD), and the production of a byproduct of peroxidation (e.g. malonedialdehyde, MDA). After UV radiation, the survival rate of P. nana was significantly reduced. Also, egg sac damage and a reduction in the hatching rate of offspring were observed in UV-irradiated ovigerous females. According to the assessed biochemical parameters, we found dose-dependent increases in ROS levels and high levels of the lipid peroxidation decomposition product by 2 kJ m(-2), implying that P. nana was under off-balanced status by oxidative stress-mediated cellular damage. Antioxidant enzyme activities of GST and SOD increased over different doses of UV radiation. To measure UV-induced lipid peroxidation, we found a slight reduction in the composition of essential fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These findings indicate that UV radiation can induce oxidative stress-triggered lipid peroxidation with modulation of antioxidant enzyme activity, leading to a significant effect on mortality and reproductive physiology (e.g. fecundity). These results demonstrate the involvement of UV radiation on essential fatty acids and its susceptibility to UV radiation in the copepod P. nana compared to other species. PMID:24952335

  5. Molecular and functional analysis of three fatty acyl-CoA reductases with distinct substrate specificities in copepod Calanus finmarchicus.

    PubMed

    Teerawanichpan, Prapapan; Qiu, Xiao

    2012-04-01

    The marine copepod Calanus finmarchicus constitutes the substantial amount of biomass in the Arctic and Northern seas. It is unique in that this small crustacean accumulates a high level of wax esters as carbon storage which is mainly comprised of 20:1n-9 and 22:1n-11 alcohols (Alc) linked with various kinds of fatty acids, including n-3 polyunsaturated fatty acids. The absence of 20:1n-9 Alc and 22:1n-11 Alc in diatoms and dinoflagellates, the primary food sources of copepods, suggests the existence of de novo biosynthesis of fatty alcohols in C. finmarchinus. Here, we report identification of three genes, CfFAR1, CfFAR2, and CfFAR3, coding for fatty acyl-CoA reductases involved in the conversion of various fatty acyl-CoAs to their corresponding alcohols. Functional characterization of these genes in yeast indicated that CfFAR1 could use a wide range of saturated fatty acids from C18 to C26 as substrates, CfFAR2 had a narrow range of substrates with only very-long-chain saturated fatty acid 24:0 and 26:0, while CfFAR3 was active towards both saturated (16:0 and 18:0) and unsaturated (18:1 and 20:1) fatty acids producing corresponding alcohols. This finding suggested that these three fatty acyl-CoA reductases are likely responsible for de novo synthesis of a series of fatty alcohol moieties of wax esters in C. finmarchicus. PMID:21918929

  6. Interactive effect of salinity decrease, salinity adaptation, and chlorpyrifos exposure on an estuarine harpacticoid copepod, Mesochra parva, in South Africa.

    PubMed

    Bollmohr, S; Schulz, R; Hahn, T

    2009-03-01

    This study tested the hypothesis: "does adaptation to fluctuating salinities lead to enhanced survival of the harpacticoid copepod M. parva when exposed to a combination of particle associated chlorpyrifos (CPF) exposure and hypoosmotic stress during a 96h sediment toxicity test?" The CPF exposure concentrations of 5.89-5.38mug/kg and the salinity decrease from 15 to 3ppt were based on conditions observed in the temporarily open Lourens River estuary, South Africa, in order to simulate changes during a runoff event. Results of the three-factorial ANOVA showed that pre-adaptation to varying salinities (p=0.02; p=0.001), salinity decrease (p=0.035; p<0.001), and CPF exposure (p<0.001; p<0.001), all had a significant negative impact on the survival rate of female and male M. parva, with a higher sensitivity of males specimens. The significant two-way interaction of salinityxadaptation for females and males (p=0.021; p<0.001), indicate that adaptation to fluctuating salinities was beneficial for male and female copepods, but the hypothesis of a three-way interaction was not supported. However, a trend indicated a lower survival rate of non-adapted females and males exposed to CPF and hypoosomotic stress (38+/-17%; 0+/-0%), compared to pre-adapted organisms (59+/-6.6%; 8.9+/-10%), which requires further elucidation. This study has important implications for the management of temporarily open estuaries in South Africa regarding regulation of freshwater abstraction from rivers. PMID:19081627

  7. Ocular lesions associated with attachment of the copepod Ommatokoita elongata (Lernaeopodidae: Siphonostomatoida) to corneas of Pacific sleeper sharks Somniosus pacificus captured off Alaska in Prince William Sound.

    PubMed

    Benz, George W; Borucinska, Joanna D; Lowry, Lloyd F; Whiteley, Herbert E

    2002-06-01

    Twenty eyes from 10 Pacific sleeper sharks Somniosus pacificus, infected with the copepod Ommatokoita elongata, were collected in Prince William Sound, Alaska, and the eyes of an additional 18 S. pacificus captured in the same area were inspected for copepods. Prevalence of infection by adult female O. elongata was 97% (n = 28); mean intensity of infection was 1.89 (+/-1SD = 0.32) adult female copepods per infected shark and 1.0 (+/- 1SD = 0.0) adult female copepods per infected eye. Five of the 20 collected eyes were infected by O. elongata chalimi, and 9 of 20 eyes had 1 to several remnants of bullae embedded in the cornea. Bullae were each associated with a corneal opacity, and anchoring plugs of chalimi were associated with pinpoint lesions in the cornea or conjunctiva. All eyes exhibited marked edema and erosion of the bulbar conjunctiva, and this torus-shaped lesion corresponded to each O. elongata adult female's presumed feeding and abrasion radius. Histological examinations revealed lesions in the anterior segment of eyes to be generally similar, but graded, in severity, and in all eyes they involved the conjunctiva, cornea, filtration angle, and iris. Epithelial lesions were characterized by corneal ulceration, dysplasia, hyperplasia, and heterophilic keratitis, and by ulcerative conjunctivitis accompanied by epithelial hyperplasia with rete peg formation. Disorganization of fibers, necrosis, mineralization, minimal heterophilic influx, and perilimbic neovascularization were associated with bullae in the corneal stroma. Within the limbus there was diffuse histiocytic and lymphocytic inflammation and marked lymphofollicular hyperplasia. Heterophilic and mononuclear anterior uveitis affecting the filtration angle and anterior surface of the iris was also observed in most eyes. One eye had a partial transcorneal prolapse of a ruptured lens, with degenerative changes in the ruptured lens and severe keratitis associated with the anchoring devices of an adult copepod and several chalimi. Fourteen eyes exhibited 1 to several, randomly distributed, small, round to irregular, corneal opacities or pits that were not associated with copepods, and it is likely that these opacities represented lesions associated with adult female or larval anchoring devices from past infections. The avascular cornea represents a niche that is somewhat shielded from host immune reactions, and this, and the fact that the general body surface of sleeper sharks is covered by tall and sharp placoid scales, may partially explain the corneal attachment of O. elongata adult females. It was concluded that O. elongata infections can lead to severe vision impairment in Pacific sleeper sharks but that these infections do not significantly debilitate hosts because they probably do not need to rely on acute vision for their survival. PMID:12099414

  8. Abundance, distribution and population structure of the copepod Calanus finmarchicus in a springtime right whale feeding area in the southwestern Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Wishner, Karen F.; Schoenherr, Jill R.; Beardsley, Robert; Chen, Changsheng

    Springtime aggregations of the planktivorous right whale ( Eubalaena glacialis) occur in the northern Great South Channel region of the southwestern Gulf of Maine, where they feed upon dense concentrations of the copepod Calanus finmarchicus. This association was studied during the multidisciplinary South Channel Ocean Productivity Experiment (SCOPEX) in 1988 and 1989. The spatial and temporal variability of the abundance, geographic distribution, and population structure of these copepods were analyzed using data from 99 vertically-stratified or horizontally-sequenced MOCNESS plankton tows. Higher water column abundances and higher relative proportion of older copepod lifestages occurred near feeding whales compared to sites without whales, but total water column copepod biomass and Calanus abundance did not always differ between these types of locations. This suggests that the whales seek out aggregations of older copepod lifestages rather than simply the most dense aggregations. Other factors (and perhaps an element of chance) may influence which specific patches, among all patches potentially suitable in terms of copepod abundance and age composition, the whales utilize at a particular time. The times and locations of the highest Calansus water column abundances varied between years, as did the presence of feeding whales, probably because of year-to-year differences in the springtime temperature cycle and current strength. A temporal progression of lifestages occurred within the region in both years during the roughly 3-week duration of each survey, indicative of a growing rather than a diapausing population, at least up to the copepodite 4 (C4) stage. Due in part to a delay in the springtime warming in 1989 compared to 1988, the copepod development cycle, which is largely driven by in situ temperature, was delayed about 1-2 weeks in 1989. Peak abundances of younger Calanus were found in the northwestern part of the region each year, whereas peak abundances of older Calanus were found in the southwestern and northeastern part. This was probably due to the advection of maturing copepods by the regional circulation, especially the near-surface current associated with the movement of the low-salinity surface plume which forms each spring off Cape Cod. The copepod development cycle occurs within a moving frame of reference (i.e. the water itself); thus, peak abundances of the older copepods (those fed on by the whales) occurred later in the spring and further downstream in 1989 (when there were colder springtime temperatures and faster currents) than in 1988 (when the springtime temperatures were warmer and currents slower). Maximum Calanus abundances and biomass and water-colum abundances of older copepodite stages were significantly higher (about double) in 1989 than in 1988, both in the region as a whole and at sites where whales were feeding. Maximum concentrations from the MOCNESS tows were 13,300 m -3 in 1988 and 30,800 m -3 in 1989; however, a thin, visibly-red surface patch of Calanus, sampled in 1989 by a bucket, had a concentration of 331,000 m -3. Copepods were also more aggregated in the vertical (i.e. more highly concentrated at the depth of maximum abundance) in 1989 than in 1988, and samples from whale-feeding areas were more homogeneous in composition (higher proportion of Calanus relative to all zooplankton) in 1989. At smaller spatial and temporal scales, abundances varied by a factor of 1-890 X in samples from horizontal tows spanning about 0.5-1.5 km and by a factor of 1-50 X over 24 h in the same geographic location in whale-feeding areas. Some of this variability was probably due to advection by the semidiurnal tidal currents. Near feeding whales, the copepod spatial distribution was patchy on small scales (with an estimated mean patch "size" of about 500 m), but the patchiness varied in texture interannually. Copepod abundances were much lower in early spring (March 1988) than in later spring (May 1988), with the March population structure dominated by adult females and the May population

  9. Fipronil effects on estuarine copepod (Amphiascus tenuiremis) development, fertility, and reproduction: a rapid life-cycle assay in 96-well microplate format.

    PubMed

    Chandler, G Thomas; Cary, Tawnya L; Volz, David C; Walse, Spencer S; Ferry, John L; Klosterhaus, Susan L

    2004-01-01

    Fipronil is a novel gamma-aminobutyric acid receptor-specific phenylpyrazole insecticide commonly used near estuarine environments for rice production, turf-grass management, and residential insect control. In this study, we evaluated the acute, developmental, and reproductive toxicity of fipronil to the estuarine harpacticoid copepod Amphiascus tenuiremis. Fipronil was highly toxic to A. tenuiremis (adult 96-h median lethal concentration [LC50] = 6.8 microg/L) and was more toxic to male copepods (96-h LC50 = 3.5 microg/L) than to nongravid female copepods (96-h LC50 = 13.0 microg/L). By using a newly developed 96-well microplate-based life-cycle toxicity test, we successfully reared single individuals of A. tenuiremis to adulthood in 200-microl microwells and concurrently assessed developmental and reproductive effects (after paired virginal matings) of environmentally relevant aqueous fipronil concentrations (0.16, 0.22, and 0.42 microg/L measured). Throughout the entire life cycle, copepod survival in all treatments was >90%. However, fipronil at 0.22 microg/L and higher significantly delayed male and female development from stage 1 copepodite to adult by approximately 2 d. More importantly, fipronil significantly halted female egg extrusion by 71% in the 0.22-microg/L fipronil treatment, and nearly eliminated reproduction (94% failure) in the 0.42-microg/L fipronil treatment. A three-generation Leslie matrix-based population growth model of fipronil reproductive and life-cycle impacts predicted a 62% decline in population size of A. tenuiremis relative to controls at only 0.16 microg/L. PMID:14768875

  10. Determining the Advantages, Costs, and Trade-Offs of a Novel Sodium Channel Mutation in the Copepod Acartia hudsonica to Paralytic Shellfish Toxins (PST)

    PubMed Central

    Finiguerra, Michael; Avery, David E.; Dam, Hans G.

    2015-01-01

    The marine copepod Acartia hudsonica was shown to be adapted to dinoflagellate prey, Alexandrium fundyense, which produce paralytic shellfish toxins (PST). Adaptation to PSTs in other organisms is caused by a mutation in the sodium channel. Recently, a mutation in the sodium channel in A. hudsonica was found. In this study, we rigorously tested for advantages, costs, and trade-offs associated with the mutant isoform of A. hudsonica under toxic and non-toxic conditions. We combined fitness with wild-type: mutant isoform ratio measurements on the same individual copepod to test our hypotheses. All A. hudsonica copepods express both the wild-type and mutant sodium channel isoforms, but in different proportions; some individuals express predominantly mutant (PMI) or wild-type isoforms (PWI), while most individuals express relatively equal amounts of each (EI). There was no consistent pattern of improved performance as a function of toxin dose for egg production rate (EPR), ingestion rate (I), and gross growth efficiency (GGE) for individuals in the PMI group relative to individuals in the PWI expression group. Neither was there any evidence to indicate a fitness benefit to the mutant isoform at intermediate toxin doses. No clear advantage under toxic conditions was associated with the mutation. Using a mixed-diet approach, there was also no observed relationship between individual wild-type: mutant isoform ratios and among expression groups, on both toxic and non-toxic diets, for eggs produced over three days. Lastly, expression of the mutant isoform did not mitigate the negative effects of the toxin. That is, the reductions in EPR from a toxic to non-toxic diet for copepods were independent of expression groups. Overall, the results did not support our hypotheses; the mutant sodium channel isoform does not appear to be related to adaptation to PST in A. hudsonica. Other potential mechanisms responsible for the adaptation are discussed. PMID:26075900

  11. Effects of temperature and nutritional state on the toxicity of acridine to the calanoid copepod, Diaptomus clavipes Schacht. [Diaptomus claripes, Daphnia magna

    SciTech Connect

    Cooney, J.D.; Gehrs, C.W.; Bunting, D.L. II

    1983-07-01

    Acute and chronic bioassays were performed on the calanoid copepod, Diaptomus clavipes, using the azaarene, acridine, as the test compound. Tests were performed at three temperatures (16/sup 0/, 21/sup 0/, 26/sup 0/C) and over a range of nutritional conditions. Survival, growth, development, and reproduction were all affected by exposure to acridine. These effects were modified by temperature and nutritional state of the animals.

  12. 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)

    Pepin, Pierre

    2013-05-01

    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.

  13. First record of association of copepods with highly venomous box jellyfish chironex, with description of new species of paramacrochiron (cyclopoida: macrochironidae).

    PubMed

    Ohtsuka, Susumu; Metillo, Ephrime; Boxshall, Geoffrey A

    2015-04-01

    Paramacrochiron chironecicola n. sp. (Copepoda: Cyclopoida: Macrochironidae) is described from the highly venomous box jellyfish Chironex sp. collected from Malampaya Sound, Palawan Island, The Philippines. This is the first record of copepods associated with cubozoan medusae, although other cnidarian groups such scyphozoans, hydrozoans, and anthozoans are common hosts for symbiotic copepods. The infection sites were on the subumbrella, pedalium, and rhopalium, but also rarely on the adradial furrow. The new species is distinguished from other congeners by a combination of the following features: (1) the fifth pedigerous somite dorsally covering the anterior part of the female genital double-somite; (2) the fine structures of the antenna (relative lengths of segments) and maxilliped (positions of terminal elements) of the female; (3) the relatively long outer spines on the exopodal segments of legs 1-4; (4) the relatively long and thick female leg 5 bearing a long protopodal seta which reaches to the distal margin of the exopod; (5) the relatively short caudal ramus in the female; and (6) the plump prosome and short urosome in the male. Since members of the genus typically parasitize scyphozoans, especially rhizostomes, the association of this parasitic copepod on cubozoans may reflect the relatively close phylogenetic relationship between cubozoans and scyphozoans. PMID:25826070

  14. Developmental retardation, reduced fecundity, and modulated expression of the defensome in the intertidal copepod Tigriopus japonicus exposed to BDE-47 and PFOS.

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Lee, Min-Chul; Seo, Jung Soo; Lee, Su-Jae; Lee, Jae-Seong

    2015-08-01

    2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and perfluorooctane sulfonate (PFOS) are widely dispersed persistent organic pollutants (POPs) in the marine ecosystem. However, their toxic effects on marine organisms are still poorly understood. In this study, we investigated the effects of BDE-47 and PFOS on development and reproduction at the organismal level and reactive oxygen species (ROS) production and gene expression patterns of the defensome at the cellular level in the intertidal copepod Tigriopus japonicus. In copepods exposed to BDE-47 and PFOS, we observed developmental retardation and reduced fecundity, suggesting repercussions on in vivo endpoints through alterations to the normal molting and reproduction system of T. japonicus. BDE-47 and PFOS increased levels of ROS in T. japonicus in a concentration-dependent manner, indicating that POPs can induce oxidative stress through the generation of ROS. Additionally, transcript profiles of genes related to detoxification (e.g., CYPs), antioxidant functions (e.g., GST- sigma, catalase, MnSOD), apoptosis (e.g., p53, Rb), and cellular proliferation (e.g., PCNA) were modulated over 72h in response to BDE-47 (120μg/L) and PFOS (1000μg/L). These findings indicate that BDE-47 and PFOS can induce oxidative stress-mediated DNA damage repair systems with transcriptional regulation of detoxification, antioxidant, and apoptosis-related genes, resulting in developmental retardation and reduced fecundity in the copepod T. japonicus. PMID:26037098

  15. Fatty acid utilisation and metabolism in caecal enterocytes of rainbow trout (Oncorhynchus mykiss) fed dietary fish or copepod oil.

    PubMed

    Oxley, Anthony; Tocher, Douglas R; Torstensen, Bente E; Olsen, Rolf E

    2005-12-15

    A combined fatty acid metabolism assay was employed to determine fatty acid uptake and relative utilisation in enterocytes isolated from the pyloric caeca of rainbow trout. In addition, the effect of a diet high in long-chain monoenoic fatty alcohols present as wax esters in oil derived from Calanus finmarchicus, compared to a standard fish oil diet, on caecal enterocyte fatty acid metabolism was investigated. The diets were fed for 8 weeks before caecal enterocytes from each dietary group were isolated and incubated with [1-14C]fatty acids: 16:0, 18:1n-9, 18:2n-6, 18:3n-3, 20:1n-9, 20:4n-6, 20:5n-3, and 22:6n-3. Uptake was measured over 2 h with relative utilisation of different [1-14C]fatty acids calculated as a percentage of uptake. Differences in uptake were observed, with 18:1n-9 and 18:2n-6 showing the highest rates. Esterification into cellular lipids was highest with 16:0 and C18 fatty acids, accounting for over one-third of total uptake, through predominant incorporation in triacylglycerol (TAG). The overall utilisation of fatty acids in phospholipid synthesis was low, but highest with 16:0, the most prevalent fatty acid recovered in intracellular phosphatidylcholine (PC) and phosphatidylinositol (PI), although exported PC exhibited higher proportions of C20/C22 polyunsaturated fatty acids (PUFA). Other than 16:0, incorporation into PC and PI was highest with C20/C22 PUFA and 20:4n-6 respectively. Recovery of labelled 18:1n-9 in exported TAG was 3-fold greater than any other fatty acid which could be due to multiple esterification on the glycerol 'backbone' and/or increased export. Approximately 20-40% of fatty acids taken up were beta-oxidised, and was highest with 20:4n-6. Oxidation of 20:5n-3 and 22:6n-3 was also surprisingly high, although 22:6n-3 oxidation was mainly attributed to retroconversion to 20:5n-3. Metabolic modification of fatty acids by elongation-desaturation was generally low at <10% of [1-14C]fatty acid uptake. Dietary copepod oil had generally little effect on fatty acid metabolism in enterocytes, although it stimulated the elongation and desaturation of 16:0 and elongation of 18:1n-9, with radioactivity recovered in longer n-9 monoenes. The monoenoic fatty acid, 20:1n-9, abundant in copepod oil as the homologous alcohol, was poorly utilised with 80% of uptake remaining unesterified in the enterocyte. However, the fatty acid composition of pyloric caeca was not influenced by dietary copepod oil. PMID:16257262

  16. Chemical composition and energy content of deep-sea calanoid copepods in the Western North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Ikeda, Tsutomu; Yamaguchi, Atsushi; Matsuishi, Takashi

    2006-11-01

    Condition factor index [CFI=1000DW/(PL) 3; DW: dry weight, PL: prosome length], water content, carbon (C), nitrogen (N), ash and energy content were determined on a total of 69 copepod species caught from the mesopelagic (500-1000 m), upper-bathypelagic (1000-2000 m), lower-bathypelagic (2000-3000 m) and abyssopelagic (3000-5000 m) zones of the western subarctic Pacific. Resultant data were grouped into these four sampling zones, four developmental stage/sex categories (C4, C5 and C6 females and males), three feeding types (carnivore, detritivore and suspension feeder), or two reaction speed groups by the presence/absence of myelinated sheath enveloping axons (fast and slow reacting species). Zone-structured data showed the overall ranges were 3.8-4.6 mm for PL, 1.6-2.6 mg for DW, 21.4-25.0 for CFI, 75.0-78.6% of wet weight (WW) for water, 51.3-53.7% of DW for C, 7.7-8.8% of DW for N, 6.2-7.0 (by weight) for C/N, 6.9-9.6% of DW for ash and 25.3-27.4 J mg -1 DW for energy. Among these components, N and ash exhibited significant between-zone differences characterized by gradual decrease downward for the former, and only the upper-bathypelagic zone>abyssopelagic zone for the latter. Stage/sex-structured data showed no significant differences among them, but energy content of C5 was higher than that of C6 females. From the analyses of feeding type-structured data, carnivores were shown to have lower water, N, ash, but higher C, C/N and energy contents than suspension feeders do. Reaction speed-structured data indicated that slow-reacting species have significantly higher water but lower CFI, C, N and energy contents than fast-reacting species. Designating these grouping criteria, PL and DW as independent variables, the attributes of these variables to the CFI, chemical composition or energy contents were evaluated by stepwise-multiple regression analysis, showing the most pronounced effect of suspension-feeder, followed by the presence of myelinated sheath, DW, C6 females and the abyssopelagic zone. Further analysis of zone-structured data, by adding epipelagic copepod data from identical thermal habitats (Arctic/Antarctic waters), revealed a more marked decline in N content from the epipelagic zone to the abyssopelagic zone, accompanied by an increase in C/N ratios downward. The decline in N (=protein or muscle) contents with depth cannot be explained by the "visual interactions" hypotheses being proposed for the metabolism of pelagic visual predators, but is consistent with the "predation-mediated selection" hypothesis for the metabolism of pelagic copepods.

  17. The influence of phytoplankton productivity, temperature and environmental stability on the control of copepod diversity in the North East Atlantic

    NASA Astrophysics Data System (ADS)

    Nogueira, Enrique; Gonzlez-Nuevo, Gonzalo; Valds, Luis

    2012-05-01

    The patterns of copepod species richness (S) and their relationship with phytoplankton productivity, temperature and environmental stability were investigated at climatological, seasonal and year-to-year time scales as well as scales along latitudinal and oceanic-neritic gradients using monthly time series of the Continuous Plankton Recorder (CPR) Survey collected in the North East Atlantic between 1958 and 2006. Time series analyses confirmed previously described geographic patterns. Equatorward and towards neritic environments, the climatological average of S increases and the variance explained by the seasonal cycle decreases. The bi-modal character of seasonality increases equatorward and the timing of the seasonal cycle takes place progressive earlier equatorward and towards neritic environments. In the long-term, the climatological average of S decreased significantly (p < 0.001) between 1958 and 2006 in the Bay of Biscay and North Iberian shelf at a rate of ca. 0.04 year-1, and increased at the same rate between 1991 and 2006 in the northernmost oceanic location. The climatological averages of S correlate positively with those of the index of seasonality of phytoplankton productivity (ratio between the minimum and maximum monthly values of surface chlorophyll) and sea surface temperature, and negatively with those of the proxy for environmental stability (monthly frequency of occurrence of daily averaged wind speed exceeding 10 m s-1). The seasonal cycles of S and phytoplankton productivity (surface chlorophyll as proxy) exhibit similar features in terms of shape, timing and explained variance, but the relationship between the climatological averages of both variables is non-significant. From year-to-year, the annual averages of S correlate negatively with those of phytoplankton productivity and positively with those of sea surface temperature along the latitudinal gradient, and negatively with those of environmental stability along the oceanic-neritic gradient. The annual anomalies of S (i.e. factoring out geographic variation) show a unimodal relationship with those of sea surface temperature and environmental stability, with S peaking at intermediate values of the anomalies of these variables. The results evidence the role of seasonality of phytoplankton productivity on the control of copepod species richness at seasonal and climatological scales, giving support to the species richness-productivity hypothesis. Although sea surface temperature (SST) is indeed a good predictor of richness along the latitudinal gradient, it is unable to predict the increase of richness form oceanic to neritic environments, thus lessening the generality of the species richness-energy hypothesis. Meteo-hydrographic disturbances (i.e. SST and wind speed anomalies as proxies), presumably through its role on mixed layer depth dynamics and turbulence and hence productivity, maximise local diversity when occurring at intermediate frequency and or intensity, thus providing support to the intermediate disturbance hypothesis on the control of copepod diversity.

  18. 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)

    Cass, Christine J.; Daly, Kendra L.

    2014-12-01

    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 μmol 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.

  19. Gamma rays induce DNA damage and oxidative stress associated with impaired growth and reproduction in the copepod Tigriopus japonicus.

    PubMed

    Han, Jeonghoon; Won, Eun-Ji; Lee, Bo-Young; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Leung, Kenneth Mei Yee; Lee, Yong Sung; Lee, Jae-Seong

    2014-07-01

    Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96h, even in response to exposure to a high dose (800Gy) of radiation, but mortality rate was significantly increased 120h (5 days) after exposure to 600 or 800Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma irradiation. Additionally, antioxidant genes, phase II enzyme (e.g. GSTs), and cellular chaperone genes (e.g. Hsps) that are involved in cellular defense mechanisms also showed the same expression patterns for sublethal doses of gamma irradiation (50-200Gy). These findings indicate that sublethal doses of gamma radiation can induce oxidative stress-mediated DNA damage and increase the expression of antioxidant enzymes and proteins with chaperone-related functions, thereby significantly affecting life history parameters such as fecundity and molting in the copepod T. japonicus. PMID:24800869

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

    PubMed

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

    2010-01-01

    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 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 characterized by a pronounced movement of the krill's antennae towards the target, followed by a propulsion and opening of the feeding basket. Frequency distributions of prey detection distances were significantly different in the light vs. the dark, with median values of 26.5 mm and 19.5 mm, respectively. There were no significant differences in the angles at which prey were detected by krill (relative to the predator's longitudinal body axis) in the light vs. the dark. Prey detections were symmetrically distributed on either side of the predator, in both light and dark. However, significant asymmetry was found in the dorsal-ventral direction with 80% of the prey detections located below the midline of the krill's body axis and, given the placement and orientation of the compound eyes, presumably outside its visual field of view. This indicates that, at least under these conditions, vision was not the main sensory modality involved in the detection of active prey by M. norvegica. However, under some circumstances, vision may provide supplemental information. Avoidance responses of copepod prey were nearly twice the velocity of their nominal background swimming speed (153 ± 48 and 85 ± 75 mm s(-1), respectively), on average taking them 43 ± 16 mm away from the predator. This is far beyond the krill's perceptual range, suggesting that the escape reaction provides an effective deterrent to predation (although perhaps less so for free-swimming krill). This information can be used to parameterize models that assess the role of krill as predators in marine ecosystems. PMID:24391246

  1. Golfingicola abyssalis gen. et sp. nov., a new endoparasitic copepod (Crustacea) in a sipunculan from abyssal depths of the Northwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Schwabe, Enrico; Maiorova, Anastassya

    2015-01-01

    Marine copepods, which inhabit the entire water column down to the seafloor, are key contributors to the food web, mainly providing a food source for many organisms in the form of zooplankton. Furthermore, they also play an important ecological role as associates or even parasites with various degrees of harm to their hosts. Copepods are found in almost all habitats and can be associated with virtually every metazoan group. A female and four males of a new endoparasitic copepod genus and species (Golfingicola abyssalis) are described from the trunk celom of the sipunculan Golfingia muricaudata (Southern, 1913), collected from the abyssal depths of the Northwest Pacific Ocean near the Kuril-Kamchatka Trench. This sipunculan species is a typical deep sea representative of the northwestern Pacific region, occurring in the Bering Sea and the abyssal regions east of the Kuril Island chain. Despite numerous records of this species, a copepod association has not been reported prior to this paper. The new parasitic copepod species is tentatively placed in the Akessonia group given its endoparasitic behavior in Sipuncula, the elongated shape, the enlarged egg strings, and the presence of subchelate antenna, as well as lateral processes in males. Golfingicola abyssalis, however, shows some peculiarities that clearly differentiate it from the remaining endoparasites in Sipuncula. As the first abyssal endoparasite in Sipuncula, the species is characterized by the complete lack of any processes in females, the presence of a mandible in females, a weakly defined prosome-urosome boundary in females, the presence of a mouth in males, the free living behavior of males, a distinctly reduced number of trunk processes in males, as well as a more modified male antenna, displaying an endopodite and a highly modified setal element. A detailed review on the morphological characters of the four species currently grouped in the Akessonia group, and systematic and biogeographic information of their relevant host taxa is provided. On the basis of morphological and ecological similarities, the new species seems to be more closely related to the northern Atlantic Akessonia occulta Bresciani and Luetzen, 1962 than to Siphonobius gephyreicola Augener, 1903 and Coelotrophus nudus Ho et al., 1981.

  2. Natural copepods are superior to enriched artemia nauplii as feed for halibut larvae (Hippoglossus hippoglossus) in terms of survival, pigmentation and retinal morphology: relation to dietary essential fatty acids.

    PubMed

    Shields, R J; Bell, J G; Luizi, F S; Gara, B; Bromage, N R; Sargent, J R

    1999-06-01

    Replicate groups of halibut larvae were fed to d 71 post-first feeding (PFF) either the marine copepod, Eurytemora velox, or Artemia nauplii doubly enriched with the marine chromist or golden algae, Schizochytrium sp., (Algamac 2000) and a commercial oil emulsion (SuperSelco). The fatty acid compositions of eyes, brains and livers from larvae fed the two diets were measured, and indices of growth, eye migration and skin pigmentation were recorded along with histological examinations of eye and liver. The docosahexaenoic acid [22:6(n-3); DHA]/eicosapentaenoic acid [20:5(n-3); EPA] ratios in Artemia nauplii enriched with the SuperSelco and Algamac 2000 were 0.4 and 1.0, respectively. The E. velox copepods were divided into two size ranges (125-250 and 250-400 microm) with the smaller size range containing the highest level of (n-3) highly unsaturated fatty acids (HUFA). The DHA/EPA ratios for the two size ranges of copepods were 2.0 and 0.9, respectively. The total lipids of eyes, brains and livers of larvae fed copepods had higher levels of DHA and lower levels of EPA than those of larvae fed enriched Artemia. The percentage of survival of the halibut larvae was significantly higher when copepods rather than enriched Artemia nauplii were fed, but larval specific growth rates did not differ. The indices of eye migration were high and not significantly different in larvae fed the two diets, but the percentage of larvae undergoing successful metamorphosis (complete eye migration and dorsal pigmentation) was higher in larvae fed copepods (40%) than in larvae fed enriched Artemia (4%). The rod/cone ratios in histological sections of the retina were 2.5 +/- 0.7 in larvae fed copepods and 1.3 +/- 0.6 in larvae fed enriched Artemia (P < 0.01). Histological examination of the livers and intestines of the larvae were consistent with better assimilation of lipid from copepods than lipid from Artemia nauplii up to 46 d post-first feeding. Thus, marine copepods are superior to enriched Artemia as food for halibut larvae in terms of survival, eye development and pigmentation, and this superiority can be related to the level of DHA in the feed. PMID:10356085

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

    PubMed Central

    Willett, Christopher S.

    2011-01-01

    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

  4. Multigenerational exposure to ocean acidification during food limitation reveals consequences for copepod scope for growth and vital rates.

    PubMed

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

    2014-10-21

    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

  5. The effect of upwelling filaments and island-induced eddies on indices of feeding, respiration and growth in copepods

    NASA Astrophysics Data System (ADS)

    Yebra, L.; Hernndez-Len, S.; Almeida, C.; Bcogne, P.; Rodrguez, J. M.

    2004-08-01

    Vertical (0-200 m) and horizontal distribution of two calanoid copepod species, Scolecithrix danae and Scottocalanus sp., were studied in relation to physical structures in the transition zone off Northwest Africa during the summer of 1999. Zooplankton biomass and indices of feeding (gut fluorescence, GF), respiration (electron transfer system activity, ETS) and structural growth (aminoacyl-tRNA synthetases activity, AARS) were assessed across (1) upwelling filaments, (2) a cyclonic eddy and (3) three anticyclonic island-induced eddies in the waters south of the Canary Islands. Hydrography was an important influence on the populations studied, enhancing their development by advecting chlorophyll enriched cold waters towards the open ocean. S. danae had highest rates in anticyclonic eddies at the limit of the upwelled waters. However, GF was more than two-fold higher inside the filaments than in the surrounding waters. Scottocalanus sp. occurred only inside the upwelling area and within upwelling filaments that advected them toward oceanic waters. The frontal zone south of Gran Canaria showed the highest AARS activities for both species.

  6. Carotenoid metabolic profiling and transcriptome-genome mining reveal functional equivalence among blue-pigmented copepods and appendicularia.

    PubMed

    Mojib, Nazia; Amad, Maan; Thimma, Manjula; Aldanondo, Naroa; Kumaran, Mande; Irigoien, Xabier

    2014-06-01

    The tropical oligotrophic oceanic areas are characterized by high water transparency and annual solar radiation. Under these conditions, a large number of phylogenetically diverse mesozooplankton species living in the surface waters (neuston) are found to be blue pigmented. In the present study, we focused on understanding the metabolic and genetic basis of the observed blue phenotype functional equivalence between the blue-pigmented organisms from the phylum Arthropoda, subclass Copepoda (Acartia fossae) and the phylum Chordata, class Appendicularia (Oikopleura dioica) in the Red Sea. Previous studies have shown that carotenoid-protein complexes are responsible for blue coloration in crustaceans. Therefore, we performed carotenoid metabolic profiling using both targeted and nontargeted (high-resolution mass spectrometry) approaches in four different blue-pigmented genera of copepods and one blue-pigmented species of appendicularia. Astaxanthin was found to be the principal carotenoid in all the species. The pathway analysis showed that all the species can synthesize astaxanthin from β-carotene, ingested from dietary sources, via 3-hydroxyechinenone, canthaxanthin, zeaxanthin, adonirubin or adonixanthin. Further, using de novo assembled transcriptome of blue A. fossae (subclass Copepoda), we identified highly expressed homologous β-carotene hydroxylase enzymes and putative carotenoid-binding proteins responsible for astaxanthin formation and the blue phenotype. In blue O. dioica (class Appendicularia), corresponding putative genes were identified from the reference genome. Collectively, our data provide molecular evidences for the bioconversion and accumulation of blue astaxanthin-protein complexes underpinning the observed ecological functional equivalence and adaptive convergence among neustonic mesozooplankton. PMID:24803335

  7. Sex without sex chromosomes: genetic architecture of multiple loci independently segregating to determine sex ratios in the copepod Tigriopus californicus.

    PubMed

    Alexander, H J; Richardson, J M L; Edmands, S; Anholt, B R

    2015-12-01

    Sex-determining systems are remarkably diverse and may evolve rapidly. Polygenic sex-determination systems are predicted to be transient and evolutionarily unstable, yet examples have been reported across a range of taxa. Here, we provide the first direct evidence of polygenic sex determination in Tigriopus californicus, a harpacticoid copepod with no heteromorphic sex chromosomes. Using genetically distinct inbred lines selected for male- and female-biased clutches, we generated a genetic map with 39 SNPs across 12 chromosomes. Quantitative trait locus mapping of sex ratio phenotype (the proportion of male offspring produced by an F2 female) in four F2 families revealed six independently segregating quantitative trait loci on five separate chromosomes, explaining 19% of the variation in sex ratios. The sex ratio phenotype varied among loci across chromosomes in both direction and magnitude, with the strongest phenotypic effects on chromosome 10 moderated to some degree by loci on four other chromosomes. For a given locus, sex ratio phenotype varied in magnitude for individuals derived from different dam lines. These data, together with the environmental factors known to contribute to sex determination, characterize the underlying complexity and potential lability of sex determination, and confirm the polygenic architecture of sex determination in T.californicus. PMID:26332493

  8. Acute and chronic toxicity of produced water from a North Sea oil production platform to the calanoid copepod Acartia tonsa

    SciTech Connect

    Girling, A.E. )

    1989-08-01

    The routine operation of offshore oil production platforms results in the discharge to the sea of produced water after it has been separated from oil drawn from the reservoir. Discharge of produced water in the UK sector of the North Sea is given an exemption from the provisions of the 1971 Prevention of Oil Pollution Act providing the monthly average oil-in-water content measured twice per day does not exceed 40 mg kg{sup {minus}1}. To assess the toxic hazard to marine organisms of produced water discharged to the North Sea, within this exemption, Shell UK Exploration and Production has implemented a research program. Methods for determining the acute and chronic toxicity of produced water to the marine calanoid copepod Acartia tonsa have been established and applied at Shell's Sittingbourne Research Centre to samples from the Shell/Esso Dunlin A platform. This paper describes the methods used to assess acute and chronic toxicity and the results of tests performed on a sample of produced water collected in February 1986. Tests were performed on subsamples of the bulk sample which: (a) were untreated (b) had been filtered and (c) biodegraded (i.e., organic substances present in the produced water were degraded by micro-organisms) and then filtered. The results of the tests are discussed in relation to the likely patterns of dilution offshore in the North Sea.

  9. Effects of temperature and nutritional state on the acute toxicity of acridine to the calanoid copepod, Diaptomus clavipes Schacht

    SciTech Connect

    Cooney, J.D.; Beauchamp, J.J.; Gehrs, C.W.

    1983-01-01

    Acute toxicity tests were performed on adult males and females of a freshwater calanoid copepod, Diaptomus clavipes Schacht, using the azaarene acridine as the test compound. Tests were performed at three temperatures (16, 21 and 26/sup 0/C) and over a range of nutritional states (fed, starved and stock). Observations on mortality were made at 24-h intervals for 96 h. Analysis of the data was based on comparisons (using different treatment combinations) of the parameters in a logistic survival function used to describe the mortality data. Median lethal concentrations (using 96-h LC/sub 50/ values) were estimated from the logistic survival function as well as from the probit function, for comparative purposes. The LC/sub 50/ values ranged from 1.64 to 6.70 mg/L, depending on temperature, nutritional state of the animals and sex. The LC/sub 50/ values were highest for animals (fed before testing) at 16/sup 0/C. As food availability decreased and temperature increased, toxicity of acridine increased up to fourfold. No significant differences in LC/sub 50/ values were found between the sexes except in starved animals at 26/sup 0/C, when males were more sensitive than females. This difference in toxicity between the sexes at 26/sup 0/C may be due to differences in nutritional stress between the sexes (at this temperature), since control mortality at this temperature was also higher in males than in females.

  10. Is there a trade-off between fecundity and egg volume in the parasitic copepod Lernanthropus cynoscicola?

    PubMed

    Timi, Juan Toms; Lanfranchi, Ana Laura; Poulin, Robert

    2005-01-01

    Negative relationships between egg number and egg size are commonly seen in many animal taxa, supporting the idea that there is a trade-off between egg number and egg size resulting from the allocation of resources to either one or the other. In parasites, where availability of resources is presumably very high, there may be fewer energetic constraints acting on allocation strategies, and the trade-off may be weakened. We investigated the association between egg number and egg volume among females of the copepod Lernanthropus cynoscicola Timi and Etchegoin, 1996, parasitic on the fish Cynoscion guatucupa (Cuvier). Both egg number and egg volume were strongly correlated with female body size. After controlling for the effects of body size, we found absolutely no evidence of a trade-off, i.e. no negative relationship, between egg number and egg volume. For a given body length, females that produce many eggs do not tend to produce relatively small eggs, and vice versa. In contrast, under conditions in which resources are plentiful, large females produce large quantities of high-quality eggs, and have a marked fitness advantage over small females. PMID:15614582

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

    PubMed

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

    2014-01-01

    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

  12. Acute toxicity of five sediment-associated metals, individually and in a mixture, to the estuarine meiobenthic harpacticoid copepod Amphiascus tenuiremis.

    PubMed

    Hagopian-Schlekat, T; Chandler, G T; Shaw, T J

    2001-04-01

    The acute effects of many individual, seawater-solubilized metals on meiobenthic copepods and nematodes are well known. In sediments, however, metals most often occur as mixtures, and it is not known whether such mixtures exhibit simple additive toxicity to meiobenthos. The estuarine meiobenthic copepod Amphiascus tenuiremis was tested in four acute (96-h) sediment bioassays to determine sediment and pore-water LC50s for single-metal exposures to copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn). Laboratory-cultured copepods were exposed to clean 98% silt:clay sediments spiked with metal chloride solutions to yield five exposure concentrations plus a control. Trimmed Spearman-Karber analysis gave sediment 96-h LC50 values of 4.4 mumole Cu/g, 5.7 mumole Ni/g, 11.9 mumole Pb/g, 10.3 mumole Zn/g, and pore-water 96-h LC50 values of 2 mumole/l, 11.7 mumole/l, and 5.7 mumole/l for Cu, Ni, and Zn, respectively. Male survival after exposure to Cu, Pb, and Ni was significantly less than female survival (alpha = 0.05). Toxicity of a combined USEPA priority metal mixture to A. tenuiremis was assessed using sediment spiked equitoxically with Cd, Cu, Ni, Pb, and Zn. The sum toxic unit that produced a median lethal dose was 0.72. The mixture had a significantly greater than additive effect on A. tenuiremis survival, with the mixture being 1.4x more toxic than that expected by simple additivity. PMID:11468968

  13. Abundance, biomass, vertical migration and estimated development rate of the copepod Calanus finmarchicus in the southern Gulf of Maine during late spring

    NASA Astrophysics Data System (ADS)

    Durbin, Edward G.; Gilman, Sharon L.; Campbell, Robert G.; Durbin, Ann G.

    Abundance, biomass, diel vertical migration and estimated in situ development in the copepod Calanus finmarchicus were investigated during late spring in 1988 and 1989 in the southern Gulf of Maine. This region is an important feeding ground for the planktivorous right whale, Eubalaena glacialis. The 1988 study took place during the declining spring bloom, with phytoplankton biomass variable, but relatively high. The 1989 study occurred after seasonal stratification, and phytoplankton biomass was low. During the 1988 cruise the dominant stage in C. finmarchicus shifted from C1-C2 to C4-C5. Stage durations during 1988 (4.0 days for C3 and 6.6 days for C4), estimated from the temporal change in stage distribution, were similar to maximal values observed in the laboratory. In contrast, during 1989 stages C4 and C5 were dominant throughout the study period and development rate was slow (estimated C4 stage duration about 24 days). Diel vertical migration patterns changed, from an absence of migration at the first two 1988 stations where younger stages predominated (C1-C3), to a very strong diel vertical migration at the later 1988 stations where stages C3-C3 predominated. This was not a simple ontogenetic change in migratory behavior since all copepodite stages at each station showed similar patterns. During 1989 dense aggregations of C. finmarchicus remained in the surface layer both day and night, and no diel vertical migration was observed. A small, nonmigratory population of late-stage C. finmarchicus was found at depth. Individual body size of these copepods was considerably greater than those found at the surface. Differences in development rate between years reflect differences in the food environment, brought about by seasonal hydrographic changes and the development of more intense stratification. Diel vertical migration patterns, however, did not show a simple relation with food availability, and it is suggested that predation may play an important role in regulating the behavior of the copepods.

  14. Effects of some environmental parameters on the reproduction and development of a tropical marine harpacticoid copepod Nitocra affinis f. californica Lang.

    PubMed

    Matias-Peralta, Hazel; Yusoff, Fatimah Md; Shariff, Mohamed; Arshad, Aziz

    2005-01-01

    The effects of salinity, temperature, and light conditions on the reproduction and development of harpacticoid copepod, Nitocra affinis f. californica under controlled laboratory conditions were determined. Seven different salinity levels (5, 10, 15, 20, 25, 30, 35 ppt), four temperatures (20, 25, 30, 35 degrees C), three different light intensities (25, 56, 130 micromol m(-2) s(-1)) and photoperiods (24 h:0 h, 1 h:23 h, 12 h:12 h LD cycle) were employed in this study. The highest (p < 0.05) overall reproduction and fastest development time were achieved by copepods reared under 30-35 ppt salinity. The optimum temperature required for the maximum reproduction was 30 degrees C while under 30 degrees C and 35 degrees C the copepod development time was shortest (p < 0.05) compared to other temperature levels. The overall reproduction was highest (p < 0.05) and development rate of N. affinis was shortest (p < 0.05) under lowest light intensity (25 micromol m(-2) s(-1)). Continuous light (24 h:0 h LD) inhibited the egg production while, continuous darkness (1 h:23 h LD) and 12 h:12 h LD significantly favoured the overall reproductive activity of the female. Photoperiods 1 h:23 h and 12 h:12 h LD yielded highest total (p < 0.05) offspring female(-1) coupled with highest (p < 0.05) survival percentage. This study illustrated that although N. affinis can tolerate wide range of environmental conditions, prolonged exposure to subnormal environments affect its reproduction and development. This study showed that this species can be mass cultured for commercial purposes and has a potential to be used for toxicity studies due to its high reproductive performance fast development and a wide range of tolerance to environmental conditions. PMID:16291188

  15. Short-term changes in the mesozooplankton community and copepod gut pigment in the Chukchi Sea in autumn: reflections of a strong wind event

    NASA Astrophysics Data System (ADS)

    Matsuno, K.; Yamaguchi, A.; Nishino, S.; Inoue, J.; Kikuchi, T.

    2015-07-01

    To evaluate the effect of atmospheric turbulence on a marine ecosystem, high-frequency samplings (two to four times per day) of a mesozooplankton community and the gut pigment of dominant copepods were performed at a fixed station in the Chukchi Sea from 10 to 25 September 2013. During the study period, a strong wind event (SWE) was observed on 18 September. After the SWE, the biomass of chlorophyll a (Chl a) increased, especially for micro-size (> 10 μm) fractions. The zooplankton abundance ranged from 23 610 to 56 809 ind. m-2 and exhibited no clear changes as a result of the SWE. In terms of abundance, calanoid copepods constituted the dominant taxa (mean: 57 %), followed by barnacle larvae (31 %). Within the calanoid copepods, small-sized Pseudocalanus spp. (65 %) and large-sized C. glacialis (30 %) dominated. In the population structure of C. glacialis, copepodid stage 5 (C5) dominated, and the mean copepodid stage did not vary with the SWE. The dominance of accumulated lipids in C5 and C6 females with immature gonads indicated that they were preparing for seasonal diapause. The gut pigment of C. glacialis C5 was higher at night and was correlated with ambient Chl a (Chl a, and a significant increase was observed after the SWE (2.6 vs. 4.5 ng pigment ind.-1). The grazing impact by C. glacialis C5 was estimated to be 4.14 mg C m-2 day-1, which corresponded to 0.5-4.6 % of the biomass of the micro-size phytoplankton. Compared with the metabolic food requirement, C. glacialis feeding on phytoplankton accounted for 12.6 % of their total food requirement. These facts suggest that C. glacialis could not maintain their population by feeding solely on phytoplankton and that other food sources (i.e., microzooplankton) must be important in autumn. As observed by the increase in gut pigment, the temporal phytoplankton bloom, which is enhanced by the atmospheric turbulence (SWE) in autumn, may have a positive effect on copepod nutrition.

  16. The complete mitogenome of the whale shark parasitic copepod Pandarus rhincodonicus norman, Newbound & Knott (Crustacea; Siphonostomatoida; Pandaridae)--a new gene order for the copepoda.

    PubMed

    Austin, Christopher M; Tan, Mun Hua; Lee, Yin Peng; Croft, Laurence J; Meekan, Mark G; Pierce, Simon J; Gan, Han Ming

    2016-01-01

    The complete mitochondrial genome of the parasitic copepod Pandarus rhincodonicus was obtained from a partial genome scan using the HiSeq sequencing system. The Pandarus rhincodonicus mitogenome has 14,480 base pairs (62% A+T content) made up of 12 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a putative 384 bp non-coding AT-rich region. This Pandarus mitogenome sequence is the first for the family Pandaridae, the second for the order Siphonostomatoida and the sixth for the Copepoda. PMID:24779605

  17. 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

    Fell, J.W.; Cefalu, R.

    1984-01-01

    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)

  18. Phylogeography of Calanus helgolandicus and the Black Sea copepod Calanus euxinus, with notes on Pseudocalanus elongatus (Copepoda, Calanoida)

    NASA Astrophysics Data System (ADS)

    Unal, Ebru; Frost, Bruce W.; Armbrust, Virginia; Kideys, Ahmet E.

    2006-08-01

    Calanus helgolandicus is a widespread epipelagic copepod species whose geographical range extends from the temperate Atlantic Ocean to the northern Mediterranean Sea. Calanus euxinus, recently designated as a distinct species though closely related to C. helgolandicus, occurs in the Black Sea. Very subtle morphological differences distinguish the two species. Pseudocalanus elongatus has a similar geographic range including North Atlantic Ocean, Mediterranean Sea and the Black Sea. In this study, population genetic variation of C. helgolandicus, C. euxinus and P. elongatus was investigated using DNA sequence variation of 540 base pair ( Calanus spp.) and 575 base pair ( P. elongatus) regions of mitochondrial cytochrome oxidase I (mtCOI) gene. C. helgolandicus was collected from the English Channel, the Adriatic Sea, and C. euxinus was collected from various regions of the Black Sea. P. elongatus was collected from the English Channel and the Black Sea. Intraspecific differentiation in mtCOI was <1% for all species; mtCOI sequence variation between C. helgolandicus and C. euxinus was <0.5%. The absence of substantial genetic differentiation between C. helgolandicus and C. euxinus is particularly striking in comparison to other close species pairs in these genera. Statistically significant haplotype frequency differences were determined for different locations of the Black Sea, English Channel, and Adriatic Sea Calanus populations ( ?2=3.94, P<0.0001). The haplotype diversity was high for all species: C. euxinus ( h=0.92), C. helgolandicus ( h?0.80), P. elongatus ( h?0.60). No haplotype sharing was reported for different locations of P. elongatus, whereas the presence of haplotype sharing between C. helgolandicus and C. euxinus was remarkable. The size distribution in terms of prosome length measurements was found to be region-specific. The lack of phylogenetic differentiation between the Calanus species pair may suggest ancestral polymorphisms. The morphological and genetic similarities between C. euxinus and C. helgolandicus raise new questions about the status of C. euxinus as a different species.

  19. Effects of methyltestosterone, letrozole, triphenyltin and fenarimol on histology of reproductive organs of the copepod Acartia tonsa.

    PubMed

    Watermann, Burkard T; Albanis, Triantafyllos A; Dagnac, Thierry; Gnass, Katarina; Ole Kusk, K; Sakkas, Vasilios A; Wollenberger, Leah

    2013-07-01

    The marine calanoid copepod Acartia tonsa was exposed to methyltestosterone (MET, 1.6-126 ?g L(-1)), letrozole (LET, 10-1000 ?g L(-1)), triphenyltin chloride (TPT, 0.0014-0.0088 ?g L(-1) TPT-Sn) and fenarimol (FEN, 2.8-105 ?g L(-1)) for 21 d covering a full life-cycle. All four compounds investigated are known to act as androgens in vertebrates. The digestive tract, musculature, nervous system, reproductive organs, gonad and accessory sexual glands were examined by light microscopy after routine staining and immune-labelling for detection of apoptosis and determination of proliferation activities. MET induced an inhibition of oogenesis, oocyte maturation and yolk formation, respectively, which was most pronounced at the lowest concentrations tested. In LET exposed males, spermatogenesis was enhanced with very prominent gamete stages; in some stages apoptosis occurred. The spermatophore was hypertrophied and displayed deformations. In females, LET induced a disorder of oogenesis and disturbances in yolk synthesis. TPT stimulated the male reproductive system at 0.0014 and 0.0035 ?g TPT-SnL(-1), whereas inhibiting effects were observed in the female gonad at 0.0088 ?g TPT-SnL(-1). In FEN exposed females proliferation of gametes was reduced and yolk formation showed irregular features at 2.8-105 ?gL(-1). In FEN exposed males an elevated proliferation activity was observed. No pathological alterations in other organ systems, e.g. the digestive tract including the hindgut acting as respiratory organ, the nervous system, or the musculature were seen. This indicates that the effects on gonads might be caused rather by disturbance of endocrine signalling or interference with hormone metabolism than by general toxicity. PMID:23664474

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

    PubMed Central

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

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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.

  2. Structure determinants for the substrate specificity of acyl-CoA ?9 desaturases from a marine copepod.

    PubMed

    Meesapyodsuk, Dauenpen; Qiu, Xiao

    2014-04-18

    In contrast to soluble acyl-ACP desaturases from plants, little is known about the structure-guiding principle underlying substrate specificity and regioselectivity of membrane-bound acyl-CoA desaturases from animals, mainly due to lack of the three-dimensional structure information. Here we report identification of two homologous membrane-bound acyl-CoA ?9 desaturases (ChDes9-1 and ChDes9-2) from the marine copepod Calanus hyperboreus that accumulates more than 90% of total storage lipids in the form of wax esters. ChDes9-2 is a common ?9 desaturase with substrate specificity to long chain fatty acid 18:0, while ChDes9-1 is a new type of ?9 desaturase introducing a ?9 double bond into a wide range of very long chain fatty acids ranging from 20:0 to 26:0. Reciprocal domain swapping and site-directed mutagenesis guided by the membrane topology revealed that presence or absence of an amphipathic and bulky residue, tyrosine, in the middle of the second transmembrane domain was important in determining the substrate specificity of the two desaturases. To examine the mechanistic structure for the substrate specificity, tyrosine-scanning mutagenesis was employed to systematically substitute the residues in the transmembrane domain of the very long chain desaturase. The results showed that the transmembrane domain formed an ?-helix structure probably involved in formation of the substrate-binding pocket and the corresponding residue of the tyrosine likely resided at the critical position within the pocket mediating the interaction with the substrates, thereby specifying the chain length of the substrates. PMID:24475735

  3. Life history strategies in zooplankton communities: The significance of female gonad morphology and maturation types for the reproductive biology of marine calanoid copepods

    NASA Astrophysics Data System (ADS)

    Niehoff, Barbara

    2007-07-01

    The present review addresses the reproductive strategies of marine calanoid copepods, as affected by their physiological preconditioning, and aims to enhance understanding of their adaptations to specific environmental conditions. Knowledge about oocyte development and internal gonad structure, especially in relation to feeding conditions, is essential for a complete understanding of the reproductive strategies of the copepods. Therefore, the foci of the review are to identify general patterns in oocyte and gonad development in calanoid copepod species from marine ecosystems worldwide and to elucidate the significance of gonad structures for reproductive strategies. Oogenesis is similar in all copepod species. During maturation, the morphology of the oocytes changes distinctly and, according to oocyte size and appearance of ooplasm and nucleus, five oocyte developmental stages are distinguished. In contrast, the gonad structure and its changes during the spawning cycle differ considerably among species, and these differences are related to specific reproductive traits. Four gonad morphology types can be distinguished: the Calanus-type, found in species from all over the world with distinctly different life history traits, is apparently most common in calanoid copepods. In this gonad type, most oocyte developmental stages are present simultaneously, and usually many oocytes mature synchronously, all of which are released in one clutch. The gonad structure allows frequent spawning and large clutches, hence, high egg production rates. This may be a preconditioning for exploiting seasonally high food supply. However, the Calanus-type was also found in species producing eggs at lower rates. In the diverticula of Pseudocalanus-type gonads, only two oocyte developmental stages are present and usually fewer oocytes mature synchronously. Accordingly, the egg production rate is generally lower as compared to the Calanus-type, and apparently only this gonad-type is structurally suitable for ovigerity. Species with Pseudocalanus-type gonads are present from polar seas to the tropics, some of them being key species. The Acartia-type was scarce, found in only one species, Acartia clausi. Here all oocyte developmental stages are present, including intermediate stages, but only a few oocytes mature synchronously and are released together. High spawning frequency compensates for the small clutches, and hence egg production rate may be as high as in Calanus-type gonads. In the Aetidius-type gonad, the total number of oocytes in the diverticula is low as is the number of oocytes maturing synchronously. Less is known about the reproductive biology of species with Aetidius-type gonads; however, their distribution and feeding patterns suggest that this type is common in species inhabiting environments of low food availability. The differences in gonad structures also lead to differences in the egg size:female size ratio, as the space available for each mature oocyte depends on the total number of oocytes. Independent from gonad-type, the eggs are relatively large in species in which the gonads contain only few oocytes, whereas small eggs are produced by species with gonads filled with many oocytes. Since all species carrying their eggs in external sacs until hatching (ovigerous species) have Pseudocalanus-type gonads, the scatter in their egg size:female size ratio is low. The broadcast spawning species are of all gonad-types, and consequently the scatter among them is high. A major factor affecting the timing and magnitude of spawning of calanoid copepods is the energy supply for gonad development. Therefore, part of the review elucidates the role of internal and external resources in fuelling egg production. In many species, freshly assimilated food is transferred into egg material within a short period of time, and clutch size and spawning frequency are the two parameters that allow adjustment of egg production to food availability and temperature. However, internal body reserves may also fuel oocyte development. The extent to which oogenesis depends on ambient feeding conditions varies considerably among species and even within species, apparently reflecting their adaptation to specific environmental conditions. All copepod species continue to release eggs for a short period after the onset of starvation, indicating that a short-term nutrient pool fuels final oocyte maturation. Some species, especially from polar and subpolar regions, are capable of reproducing on internal reserves, either solely or in addition to freshly ingested food, hence, decoupling the reproduction to some extent from the spring bloom. The reproductive strategy of Calanus finmarchicus, which responds with extreme flexibility to variations in food supply, is presented here as an example for the complexity of the reproductive processes in a calanoid copepod. In accordance with their physiological pre-conditioning, the calanoid copepod species exhibit distinctly different reproductive patterns. Polar and sub-polar environments are characterized by strong seasonality in light regime, and hence, phytoplankton concentration. The reproductive activity of many dominant (herbivorous) species peaks during the spring bloom. However, species that utilize internal reserves or food resources other than phytoplankton, reproduce before and after the bloom, or even year-round. In the North Atlantic, presented here as an example for a boreal marine ecosystem, maximum reproduction of the dominant copepod species Calanus finmarchicus occurs during the spring bloom. However, the timing of peak spawning varies between areas, as the onset of the bloom varies with hydrography and climate. The subtropical Gulf of Aqaba, in contrast to other subtropical systems, is characterized by seasonal phytoplankton succession driven by thermal winter convection. These changing environmental conditions, however, did not affect the reproduction of two of the dominant species, Clausocalanus farrani and C. furcatus. In contrast, other calanoid species exhibit reproductive cycles, either related to temperature ( Ctenocalanus vanus) or to ontogenetic migration ( Rhincalanus nasutus). The information gained from studies of morphology and reproductive traits contributes to standardization of methods in reproductive studies. Based on detailed knowledge of gonad morphology and its changes during maturation and due to food supply, classification schemata have been developed allowing the identification of females ready to spawn. In a next step, egg production may be estimated from preserved females by assessing clutch size through the number of maturing oocytes in the gonads. This approach, however, is as yet applicable only to the species best studied, Calanus finmarchicus. The present review shows that morphological studies on gonad maturation processes may provide significant contributions to fundamental ecological questions. Thus, they extend our knowledge of reproductive ecology from simply relating reproductive traits to abiotic and biotic factors toward a mechanistic understanding of how reproduction is regulated in calanoid copepods.

  4. A new genus and family of copepods (Crustacea: Copepoda) parasitic
    on polychaetes of the genus Jasmineira Langerhans, 1880 (family Sabellidae) in the northeastern Atlantic.

    PubMed

    Boxshall, Geoff A; O'reilly, Myles; Sikorski, Andrey; Summerfield, Rebecca

    2015-01-01

    A new genus and species of copepod, Jasmineiricola mackiei n. gen. et n. sp., parasitic on at least three species of the sabellid polychaete genus Jasmineira Langerhans, 1880 is described. The adult female is mesoparasitic, living with part of its body (the endosoma) embedded within the host and part (the ectosoma) protruding through the host's body wall. The endosoma consists of a well defined head region carried anteriorly on the trunk which has paired lateral lobes housing the ovaries. The head bears a rosette-like array of eight slender lobes, which are probably derived from the mouthparts. The only limbs present on the trunk are the subchelate maxillipeds positioned immediately posterior to the head. The ectosoma consists of a posterior genito-abdominal lobe bearing paired genital apertures. The male is unknown. The new genus cannot be placed in any of the five existing families of mesoparasitic copepods on polychaete hosts and is treated as the type of a new monotypic family, the Jasmineiricolidae. The new species occurs over a depth range from 19 to 279 m, and is widely distributed from UK coastal waters to Norwegian waters inside the Arctic Circle. PMID:26624049

  5. 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)

    Noyon, Margaux; William Froneman, P.

    2013-12-01

    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.

  6. Lipid and fatty acid composition of diatoms revisited: rapid wound-activated change of food quality parameters influences herbivorous copepod reproductive success.

    PubMed

    Wichard, Thomas; Gerecht, Andrea; Boersma, Maarten; Poulet, Serge A; Wiltshire, Karen; Pohnert, Georg

    2007-07-01

    Lipid and fatty acid composition are considered to be key parameters that determine the nutritive quality of phytoplankton diets for zooplanktonic herbivores. The fitness, reproduction and physiology of the grazers are influenced by these factors. The trophic transfer of lipids and fatty acids from algal cells has been typically studied by using simple extraction and quantification approaches, which, as we argue here, do not reflect the actual situation in the plankton. We show that cell disruption, as it occurs during a predator's grazing on diatoms can drastically change the lipid and fatty acid content of the food. In some algae, a rapid depletion of polyunsaturated fatty acids (PUFAs) is observed within the first minutes after cell disruption. This fatty acid depletion is directly linked to the production of PUFA-derived polyunsaturated aldehydes (PUA); these are molecules that are thought to be involved in the chemical defence of the algae. PUA-releasing diatoms are even capable of transforming lipids from other sources if these are available in the vicinity of the wounded cells. Fluorescent staining reveals that the enzymes involved in lipid transformation are active in the foregut of copepods, and therefore link the depletion processes directly to food uptake. Incubation experiments with the calanoid copepod Temora longicornis showed that PUFA depletion in PUA-producing diatoms is correlated to reduced hatching success, and can be compensated for by externally added single fatty acids. PMID:17541989

  7. Reverse genetics in the tide pool: knock-down of target gene expression via RNA interference in the copepod Tigriopus californicus.

    PubMed

    Barreto, Felipe S; Schoville, Sean D; Burton, Ronald S

    2015-07-01

    Reverse genetic tools are essential for characterizing phenotypes of novel genes and testing functional hypotheses generated from next-generation sequencing studies. RNA interference (RNAi) has been a widely used technique for describing or quantifying physiological, developmental or behavioural roles of target genes by suppressing their expression. The marine intertidal copepod Tigriopus californicus has become an emerging model for evolutionary and physiological studies, but this species is not amenable to most genetic manipulation approaches. As crustaceans are susceptible to RNAi-mediated gene knock-down, we developed a simple method for delivery of gene-specific double-stranded RNA that results in significant suppression of target gene transcription levels. The protocol was examined on five genes of interest, and for each, at least 50% knock-down in expression was achieved. While knock-down levels did not reach 100% in any trial, a well-controlled experiment with one heat-shock gene showed unambiguously that such partial gene suppression may cause dramatic changes in phenotype. Copepods with suppressed expression of heat-shock protein beta 1 (hspb1) exhibited dramatically decreased tolerance to high temperatures, validating the importance of this gene during thermal stress, as proposed by a previous study. The application of this RNAi protocol in T. californicus will be invaluable for examining the role of genes putatively involved in reproductive isolation, mitochondrial function and local adaptation. PMID:25487181

  8. Identification and developmental expression of the enzymes responsible for dopamine, histamine, octopamine and serotonin biosynthesis in the copepod crustacean Calanus finmarchicus

    PubMed Central

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

    2013-01-01

    Neurochemicals are likely to play key roles in physiological/behavioral control in the copepod crustacean Calanus finmarchicus, the biomass dominant zooplankton for much of the North Atlantic Ocean. Previously, a de novo assembled transcriptome consisting of 206,041 unique sequences was used to characterize the peptidergic signaling systems of Calanus. Here, this assembly was mined for transcripts encoding enzymes involved in amine biosynthesis. Using known Drosophila melanogaster proteins as templates, transcripts encoding putative Calanus homologs of tryptophan-phenylalanine hydroxylase (dopamine, octopamine and serotonin biosynthesis), tyrosine hydroxylase (dopamine biosynthesis), DOPA decarboxylase (dopamine and serotonin biosynthesis), histidine decarboxylase (histamine biosynthesis), tyrosine decarboxylase (octopamine biosynthesis), tyramine ?-hydroxylase (octopamine biosynthesis) and tryptophan hydroxylase (serotonin biosynthesis) were identified. Reverse BLAST and domain analyses show that the proteins deduced from these transcripts possess sequence homology to and the structural hallmarks of their respective enzyme families. Developmental profiling revealed a remarkably consistent pattern of expression for all transcripts, with the highest levels of expression typically seen in the early nauplius and early copepodite. These expression patterns suggest roles for amines during development, particularly in the metamorphic transitions from embryo to nauplius and from nauplius to copepodite. Taken collectively, the data presented here lay a strong foundation for future gene-based studies of aminergic signaling in this and other copepod species, in particular assessment of the roles they may play in developmental control. PMID:24148657

  9. 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

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

    2014-01-01

    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

  10. Pan-North Pacific comparison of long-term variation in Neocalanus copepods based on stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Chiba, Sanae; Sugisaki, Hiroya; Kuwata, Akira; Tadokoro, Kazuaki; Kobari, Toru; Yamaguchi, Atsushi; Mackas, David L.

    2012-05-01

    Regional differences in the mechanisms of temporal variation in the lower trophic levels in the western, central, and eastern subarctic North Pacific were studied using the nitrogen stable isotope ratio (?15N) of the major copepod species, Neocalanus cristatus, Neocalanus flemingeri, and Neocalanus plumchrus. We used formalin-preserved specimens collected in the Oyashio region (OY), three sections from north to south along the 180 longitudinal line (180LineSA, TN, and TS), off Vancouver Island (Off-Van), and at Sta. P, during the periods of 1960-2000, 1979-1997, 1981-2007, and 1996-2007, respectively. The regional mean ?15N of the three species roughly corresponded to the surface nitrate distribution and the extent of its drawdown from winter to spring; it was higher in regions of larger seasonal drawdown as observed in the coastal regions OY and Off-Van (7-10), but lower in regions with less seasonal drawdown, such as in the offshore regions at St. P and stations along the 180Line (3-6). Time series analysis revealed possible region-specific mechanisms for temporal variation in Neocalanus ?15N. First, ?15N indicated shifts in feeding strategies between herbivorous to omnivorous/carnivorous at OY and 180LineSA, where ?15N tended to be lower in the years with warmer winters, suggesting that Neocalanus took advantage of enhanced phytoplankton production under favorable light availability due to increased stratification. Conversely, wind-induced latitudinal advection of surface water was considered to be the initial cause of interannual variation in Neocalanus ?15N at 180LineTN, 180LineTS, and Off-Van, where ?15N was higher in the years with strong southerly or westerly winds at 180LineTN and TS, and the Off-Van site. This suggests that pole-ward transport of relatively oligotrophic, southern water might enhance the uptake of the heavier isotope by phytoplankton, which Neocalanus feed upon. Another possibility at the Off-Van site, where high ?15N was observed (c.a., 8-10), is a switch in the Neocalanus feeding strategy induced by decreased phytoplankton availability. This study demonstrated the usefulness of zooplankton ?15N as an indicator of interannual variation in lower trophic level environments and food web structures, which are caused by region-specific mechanisms.

  11. A critical body residue approach for predicting persistent bioaccumulative toxicant effects on reproduction and population dynamics of meiobenthic copepods.

    PubMed

    Chandler, G Thomas; Ferguson, P Lee; Klauber, W W; Washburn, K M

    2012-05-01

    Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose-response on a dry-weight or lipid-normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E-2317-14) produced biomass sufficient for dry mass and lipid-normalized CBR estimates of reproduction (fertility) and population growth suppression. Significant FS toxic effects were delayed naupliar development (at ≥0.10 µg L(-1)), delayed copepodite development (at 0.85 µg L(-1)), decreased reproductive success (at ≥ 0.39 µg L(-1)), and decreased offspring production (at 0.85 µg L(-1)). A reproductive median effective concentration (EC50) of 0.16 µg L(-1) (95% CI: 0.12-0.21 µg L(-1)) corresponded to an adult all-sex CBR and lipid-normalized CBR of 0.38 pg FS · µg(-1) dry weight (95% CI: 0.27-0.52 pg FS · µg(-1)) or 2.8 pg FS · µg(-1) lipid (95% CI: 2.2-3.6 pg FS · µg(-1)), respectively. Copepod log bioconcentration factor (BCF) = 4.11 ± 0.2. Leslie matrix projections regressed against internal dose predicted fewer than five gravid females in a population by the third generation at 0.39 and 0.85 µg FS · L(-1) (i.e., 9.6-10.2 µg FS · µg(-1) lipid), and 50% population suppression at a CBR of 1.6 pg FS · µg(-1) lipid. This more integrative population CBR as a management tool would fall 1.75 times below the CBR for the single most sensitive endpoint-fertility rate. PMID:22331616

  12. On the surprising lack of differences between two congeneric calanoid copepod species, Calanus finmarchicus and C. helgolandicus

    NASA Astrophysics Data System (ADS)

    Wilson, Robert J.; Speirs, Douglas C.; Heath, Michael R.

    2015-05-01

    The important calanoid copepod species Calanus finmarchicus and C. helgolandicus have distinct geographic ranges which are changing under the influence of climate change. Understanding the mechanisms underlying their distributions is becoming increasingly important as a result of the possible ecological impacts of these range shifts. Here we review inter-species differences in key life cycle traits that influence each species' geographic distribution, in particular development and growth, fecundity, feeding behaviour, vertical migration and overwintering behaviour. The distinct temperature niche of each species leads to an a priori assumption that the response of life cycle traits to temperature is a key determinant of their contrasting geographic distributions. A new development model was created to reconcile published experimental development times for each species. Model output indicates that at temperatures below approximately 12-13 C, C. finmarchicus is the faster developing species, but above these temperatures C. helgolandicus develops more quickly. Conventionally Calanus development time is assumed to decrease monotonically with temperature; however our model indicates that the response of development time to temperature is instead U-shaped. Differences in life cycle aspects such as seasonality and vertical structuring are interpreted in light of this development model. Body size and lipid accumulation abilities could be significant influences on each species' geographic distribution; however evidence is consistent with inter-species differences not existing for these traits. Published evidence shows that inter-species differences in egg production may exist, but do not follow a clear pattern. Diapause is an important and well studied life cycle adaptation of C. finmarchicus, but has received little attention in C. helgolandicus. We reviewed knowledge of diapause and suggest the hypothesis that C. helgolandicus is restricted to continental shelf regions as a result of an inability to diapause for significant periods. This synthesised view of each species' respective life cycle traits is that response of growth and development to temperature is the only known difference between each species, which indicates a promising direction for the extension of population models of C. finmarchicus to C. helgolandicus.

  13. Characterisation of iron regulatory protein 1A and 1B in the blood-feeding copepod Lepeophtheirus salmonis.

    PubMed

    Tre, Christiane; Kongshaug, Heidi; Dondrup, Michael; Nilsen, Frank

    2015-10-01

    During its parasitic life stages, the marine ectoparasitic copepod Lepeophtheirus salmonis ingests large amounts of host blood, which contains high amounts of iron. Iron is an essential micronutrient, but also toxic in high dosages, and blood-feeding parasites like the salmon louse must thus possess an efficient system to handle the excess iron. Iron regulatory protein 1 and 2 (IRP1 and IRP2) are known to play crucial roles in this process, by regulating several proteins involved in iron transport and storage, depending on the cellular iron concentration. To gain knowledge about the regulation of the iron metabolism in salmon lice, two IRP homologues (LsIRP1A and LsIRP1B) were identified by sequence and predicted structure similarity to known IRPs in other species. In situ hybridisation revealed that LsIRP1A and LsIRP1B mRNAs were expressed in the ovaries, oviducts and vitellogenic oocytes of adult females. Transcription levels of LsIRP1A and LsIRP1B mRNAs did not differ significantly between the different developmental stages of the salmon louse. Adults in the absence of blood as a feed source had decreased levels of LsIRP1A, but not LsIRP1B mRNA. RNA binding experiments indicated the presence of functioning IRP in salmon lice. In order to explore the biological functions of LsIRP1A and LsIRP1B, the mRNAs of both proteins were knocked down by RNA interference (RNAi) in preadult females. The knockdown was confirmed by qRT-PCR. LsIRP1B knockdown lice produced less offspring than control lice due to slightly shorter egg strings and had decreased levels of transcripts involved in egg development. Knockdown of both LsIRP1A and LsIRP1B caused increased expression of a salmon louse Ferritin (LsFer). These results confirm that salmon lice have two IRP1 homologues, LsIRP1A and LsIRP1B, and might suggest a function in cellular iron regulation in the reproductive organs and eggs. PMID:26115940

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

    NASA Astrophysics Data System (ADS)

    Unal, Ebru; Bucklin, Ann

    2010-10-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Auel, Holger; Hagen, Wilhelm

    2005-07-01

    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.

  16. 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)

    Gowing, Marcia M.; Wishner, Karen F.

    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.

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

    USGS Publications Warehouse

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

    2013-01-01

    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.

  18. Spatial distribution of the copepod Centropages typicus in Ligurian Sea (NW Mediterranean). Role of surface currents estimated by Topex-Poseidon altimetry.

    PubMed

    Molinero, Juan Carlos; Nival, Paul

    2004-12-01

    A particle-tracking model was used to simulate the dispersion and development of the planktonic copepod Centropages typicus during spring in Ligurian Sea. We show that mesoscale current structure, with a coastal jet and eddies, plays a key role in the transport and dispersion of C. typicus during its life cycle. Although, in the north, offshore Nice, cohorts can be advected southwestward out of Ligurian basin, more to the south others are retained in the central eddy and may give the start to the spring bloom of this species. However, input of individuals from the south through the Corsican Channel and along the west coast of Corsica may also be important in spring. This study shows that the ambit of C. typicus population is larger than the Ligurian Sea. PMID:15656353

  19. 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)

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

    2012-09-01

    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.

  20. 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)

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

    2014-04-01

    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.

  1. A new parasitic copepod (Cyclopoida: Bomolochidae) from a ponyfish (Leiognathidae) caught in Egyptian Mediterranean waters, with a review of hosts and key to species of Nothobomolochus.

    PubMed

    El-Rashidy, Hoda Hassan; Boxshall, Geoffrey Allan

    2014-02-01

    A new bomolochid copepod belonging to the genus Nothobomolochus Vervoort, 1962 is described from a Red Sea fish species, a ponyfish of the family Leiognathidae that has become established in the Eastern Mediterranean. The new species, N. leiognathicola n. sp., is based on material obtained from the gill chamber of the Red Sea immigrant ponyfish Leiognathus klunzingeri (Steindachner), caught in Egyptian waters off the Alexandria coast at Abuqir. A second new species, N. monodi n. sp., is established to accommodate some material previously described as N. denticulatus (Bassett-Smith, 1898), from the host Hemiramphus far Forsskl. A review of host records reveals that Nothobomolochus species utilise hosts representing five different orders, but are most commonly found on beloniform, clupeiform and perciform fishes. A newly constructed key to the 37 valid species of Nothobomolochus is presented. PMID:24474035

  2. Gyrodinium undulans Hulburt, a marine dinoflagellate feeding on the bloom-forming diatom Odontella aurita, and on copepod and rotifer eggs

    NASA Astrophysics Data System (ADS)

    Drebes, G.; Schnepf, E.

    1998-03-01

    The marine dinoflagellate Gyrodinium undulans was discovered as a feeder on the planktonic diatom Odontella aurita. Every year, during winter and early spring, a certain percentage of cells of this bloom-forming diatom, in the Wadden Sea along the North Sea coast, was regularly found affected by the flagellate. Supplied with the food diatom O. aurita the dinoflagellate could be maintained successfully in clonal culture. The vegetative life cylce was studied, mainly by light microscopy on live material, with special regard to the mode of food uptake. Food is taken up by a so-called phagopod, emerging from the antapex of the flagellate. Only fluid or tiny prey material could be transported through the phagopod. Larger organelles like the chloroplasts of Odontella are not ingested and are left behind in the diatom cell. Thereafter, the detached dinoflagellate reproduces by cell division, occasionally followed by a second division. As yet, stages of sexual reproduction and possible formation of resting cysts could not be recognized, neither from wild material nor from laboratory cultures. Palmelloid stages (sometimes with a delicate wall) occurring in ageing cultures may at least partly function as temporary resting stages. The winter species G. undulans strongly resembles Syltodinium listii, a summer species feeding on copepod and rotifer eggs. Surprisingly, in a few cases this prey material was accepted by G. undulans as well, at least under culture conditions. When fed with copepod eggs, the dinoflagellate developed into a large trophont, giving rise thereafter by repeated binary fission to 4, 8 or 16 flagellates, as a result of a single feeding act. A re-examination of both species under simultaneous culture conditions is planned.

  3. 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

    2012-01-01

    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