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Sample records for cyclopoid copepod paracyclopina

  1. 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

  2. Identification of Hox genes and rearrangements within the single homeobox (Hox) cluster (192.8 kb) of the cyclopoid copepod (Paracyclopina nana).

    PubMed

    Kim, Hui-Su; Kim, Bo-Mi; Lee, Bo-Young; Souissi, Sami; Park, Heum Gi; Lee, Jae-Seong

    2016-03-01

    We report the first identification of the entire complement of the eight typical homeobox (hox) genes (lab, pb, Dfd, scr, antp, ubx, Abd-A, and Abd-B) and the ftz gene in a 192.8 kb region in the cyclopoid copepod Paracyclopina nana. A Hox3 gene ortholog was not present in the P. nana hox gene cluster, while the P. nana Dfd gene was transcribed in the opposite direction to the Daphnia pulex Dfd gene, but in the same direction as the Dfd genes of the fruit fly Drosophila melanogaster and red flour beetle Tribolium castaneum. The location of the lab and pb genes was switched in the P. nana hox cluster, while the order of the remaining hox genes was generally conserved with those of other arthropods. J. Exp. Zool. (Mol. Dev. Evol.) 9999B:XX-XX, 2016. © 2016 Wiley Periodicals, Inc. PMID:26833546

  3. 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.

  4. Origin and evolution of the parasitic cyclopoid copepods.

    PubMed

    Ho, J S

    1994-12-01

    Six of the 10 recognised families of the order Cyclopoida are parasitic, with 4 of them occurring on marine invertebrates and the remaining 2 on freshwater gastropods and fishes, respectively. A cladistic analysis of the 10 families indicates that evolution of parasitism occurred twice in the history of the cyclopoids. The first attempt was made by the marine epibenthic ancestors seeking food and shelter in sessile tunicates--the ascidians. This event led to the evolution of 2 ascidicolous families: Archinotodelphyidae and Notodelphyidae. The descendant of this lineage had also invaded the mantle cavity of marine bivalve molluscs, eventually leading to the evolution of the Mantridae. The second attempt for the parasitic mode of life was launched by the ancestor which was the sister group of the ancestral cyclopoids--the most successful family of freshwater copepods. This ancestral stock, while living in the coastal zone, split into 2 groups: one group stayed behind in the ocean and colonised again the ascidians; the other groups invaded freshwater and evolved into the fish-parasitising Lernaeidae and the gastropod-parasitising Ozmanidae. PMID:7729982

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

    PubMed

    Won, Eun-Ji; Lee, Jae-Seong

    2014-05-01

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

  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 35.2±6.6 (range 20-52) for O. media and 24.4±4.5 (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 8.05±3.78 days for O. media and 7.9±0.89 days for O. scottodicarloi. The interclutch period for the females that produced new egg sacs was 2.2±1.3 days for O. media and 3±2.7 days for O. scottodicarloi. The average recruitment of O. media was 7.6±3.7 nauplii f-1 d-1, with the minimum

  7. In vivo effects of UV radiation on multiple endpoints and expression profiles of DNA repair and heat shock protein (Hsp) genes in the cycloid copepod Paracyclopina nana.

    PubMed

    Won, Eun-Ji; Han, Jeonghoon; Lee, Yeonjung; Kumar, K Suresh; Shin, Kyung-Hoon; Lee, Su-Jae; Park, Heum Gi; Lee, Jae-Seong

    2015-08-01

    To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0-3kJ/m(2)) of UV. After UV radiation, we measured the re-brooding success, growth pattern of newly hatched nauplii, ingestion rate, and assimilation of diet. In addition, we checked the modulated patterns of DNA repair and heat shock protein (hsp) chaperoning genes of P. nana. UV-B radiation induced a significant reduction (7-87%) of the re-brooding rate of ovigerous females, indicating that UV-induced egg sac damage is closely correlated with a reduction in the hatching rate of UV-irradiated ovigerous female offspring. Using chlorophyll a and stable carbon isotope incubation experiments, we found a dose-dependent decrease (P<0.05) in food ingestion and the rate of assimilation to the body in response to UV radiation, implying that P. nana has an underlying ability to shift its balanced-energy status from growth and reproduction to DNA repair and adaptation. Also, expression of P. nana base excision repair (BER)-associated genes and hsp chaperoning genes was significantly increased in response to UV radiation in P. nana. These findings indicate that even 1kJ/m(2) of UV radiation induces a reduction in reproduction and growth patterns, alters the physiological balance and inhibits the ability to cope with UV-induced damage in P. nana. PMID:26001085

  8. 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

  9. Ten new species of parasitic cyclopoid copepods (Crustacea) belonging to the families Bomolochidae, Philichthyidae, and Taeniacanthidae from marine fishes in Korea

    NASA Astrophysics Data System (ADS)

    Kim, Il-Hoi; Moon, Seong Yong

    2013-12-01

    Ten new species of cyclopoid copepods are described as parasites of marine fishes from Korea. Three new species of the family Bomolochidae are described as gill parasites: Orbitacolax pteragogi n. sp. from Pteragogus flagellifer (Valenciennes), Orbitacolax trichiuri n. sp. from Trichurus lepturus Linnaeus, and Orbitacolax unguifer n. sp. from Evynnis japonica Tanaka. Four species of the genus Colobomatus Hesse, 1873 of the family Philichthyidae are described as internal parasites: Colobomatus unimanus n. sp. from Pseudolabrus eoethinus (Richardson), Colobomatus recticaudatus n. sp. from Halichoeres poecilopterus (Temminck and Schlegel), Colobomatus floridus n. sp. from Hapalogenys mucronatus (Eydoux and Souleyet), and Colobomatus orientalis n. sp. from Johnius grypotus (Richardson). Three new species of the family Taeniacanthidae, including a new species belonging to a new genus, are described as gill parasites: Taeniacanthus singularis n. sp. from Halieutaea fumosa Alcock, Triacanthus luteus n. gen. n. sp. from Odontamblyopus lacepedii (Temminck and Schlegel), and Umazuracola geminus n. sp. from Stephonolepis cirrhifer (Temminck and Schlegel).

  10. Giselinidae fam. nov., a new monophyletic group of cyclopoid copepods (Copepoda, Crustacea) from the Atlantic deep sea

    NASA Astrophysics Data System (ADS)

    Martínez Arbizu, Pedro

    2000-12-01

    Four new species of Cyclopoida from deep-sea waters are described and placed in two new genera: Giselina gen. n. and Sensogiselina gen. n. The new genera and species belong to a new monophyletic group within the cyclopinid cyclopoids. A new name, Giselinidae, is proposed for this monophylum. The new family is characterised by the combination of the following characters: (1) tergite of leg 1 fused to cephalosome dorsally, but incompletely fused laterally, (2) absence of aesthetascs on ancestral antennulary segments XVI, XXI and XXV, (3) absence of antennary exopodal setae, (4) presence of only three spines on distal exopodal segment of leg 1, (5) absence of inner setae on first endopodal segments of legs 1-4, (6) outer terminal and distal inner elements of distal endopodal segment of leg 4 transformed into spines, (7) distal outer element of leg 5 exopod transformed into a spine, (8) leg 6 with only one seta, and (9) furcal setae I and III located on dorsal margin.

  11. Copepods Oithona similis and Oithona davisae: Two strategies of ecological-physiological adaptation in the Black Sea

    NASA Astrophysics Data System (ADS)

    Hubareva, E. S.; Svetlichny, L. S.

    2016-03-01

    Salinity tolerance, energy metabolism, buoyancy, and passive sinking and swimming speeds have been studied for comparative assessment of the adaptive potential of two species of cyclopoid copepods in the Black Sea, the native Oithona similis and new invader Oithona davisae. Both species were considered marine euryhaline copepods, but the range of salinity tolerance of O. davisae was much broader (5-55‰). The energy metabolism, locomotor activity, mean body mass density, and speed of passive sinking at the same temperature were significantly higher in O. davisae than in O. similis. The relationship between the physiological and behavioral parameters and ecological characteristics of the species are discussed.

  12. 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

    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

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

    PubMed Central

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

    2015-01-01

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

  14. The introduced Asian parasitic copepod Neoergasilus japonicus (Harada) (Cyclopoida: Ergasilidae) from endangered cichlid teleosts in Mexico.

    PubMed

    Suárez-Morales, Eduardo; Paredes-Trujillo, Amelia; González-Solís, David

    2010-11-01

    The cyclopoid copepod Neoergasilus japonicus ( Harada, 1930 ) is recorded from three endangered or threatened fish species from southeast Mexico: the tailbar cichlid Vieja hartwegi (Taylor and Miller, 1980); the Angostura cichlid V. breidohri (Werner and Stawikowski, 1987); and the sieve cichlid C. grammodes (Taylor and Miller, 1980). This ectoparasitic copepod is considered, together with most other members of Neoergasilus, an Eastern Asian form. N. japonicus is one of the most widespread parasitic Asian copepods, as it has rapidly invaded Europe and North America, including Mexico. We estimated the prevalence, mean abundance, and intensity of infection of N. japonicus in these cichlid teleosts; our data agree with previous works stating the high prevalence of this ectoparasite. This copepod has a wide range of hosts among freshwater fish taxa, but this is only the second published report from cichlids in the Neotropical region. The three cichlids surveyed, V. hartwegi, V. breidohri, and C. grammodes, are new hosts of this copepod. Its occurrence in Mexico is attributed to different events of introduction by human agency. This is the southernmost record of N. japonicus in continental America. It is a matter of concern that this copepod is parasitizing endangered or threatened endemic cichlids in the Neotropical region. Because its high infective efficiency and ability to shift hosts, this Asian parasite is expected to spread farther southwards into Central and South America. PMID:21039123

  15. 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

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

    PubMed

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

    2015-01-01

    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

  17. 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.

  18. 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.

  19. What factors drive copepod community distribution in the Gulf of Gabes, Eastern Mediterranean Sea?

    PubMed

    Drira, Zaher; Bel Hassen, Malika; Ayadi, Habib; Aleya, Lotfi

    2014-02-01

    The spatial and temporal variations in copepod communities were investigated during four oceanographic cruises conducted between July 2005 and March 2007 aboard the R/V Hannibal. A close relationship was observed between the temperature, salinity, hydrographic properties and water masses characterising the Gulf of Gabes. Indeed, water thermal stratification began in May-June, and a thermocline was established at a 20-m depth, but ranged from 25 m in July to more than 30 m in September. The zooplankton community is dominated by copepods representing 69 % to 83 % of total zooplankton. Spatial and temporal variation of copepods in relation to environmental factors shows their close relationship with the hydrodynamic features of the water column. Thermal stratification in the column, established in summer, supports copepod development. In fact, copepod abundance increases gradually with rising water temperature and salinity, starting from the beginning of thermal stratification (May-June 2006) and lasting until its completion (July 2005 and September 2006). When the water column is well mixed (March 2007), copepod abundance decreased. Our finding shows that temperature and salinity seem to be the most important physical factors and thus strongly influence the taxonomic diversity and distribution of the copepod population. They are characterised by the dominance of Oithona nana, representing 75-86 % of total cyclopoid abundance. The most abundant species during the stratification period were O. nana, Acartia clausi and Stephos marsalensis in July 2005 and September 2006. However, during the mixing period, Euterpina acutifrons was more abundant, representing 21 % of the total. Unlike the copepod community, which is more abundant during the period of high stratification, phytoplankton proliferates during semi-mixed conditions. PMID:24170503

  20. Billions of basepairs of recently expanded, repetitive sequences are eliminated from the somatic genome during copepod development

    PubMed Central

    2014-01-01

    Background Chromatin diminution is the programmed deletion of DNA from presomatic cell or nuclear lineages during development, producing single organisms that contain two different nuclear genomes. Phylogenetically diverse taxa undergo chromatin diminution — some ciliates, nematodes, copepods, and vertebrates. In cyclopoid copepods, chromatin diminution occurs in taxa with massively expanded germline genomes; depending on species, germline genome sizes range from 15 – 75 Gb, 12–74 Gb of which are lost from pre-somatic cell lineages at germline – soma differentiation. This is more than an order of magnitude more sequence than is lost from other taxa. To date, the sequences excised from copepods have not been analyzed using large-scale genomic datasets, and the processes underlying germline genomic gigantism in this clade, as well as the functional significance of chromatin diminution, have remained unknown. Results Here, we used high-throughput genomic sequencing and qPCR to characterize the germline and somatic genomes of Mesocyclops edax, a freshwater cyclopoid copepod with a germline genome of ~15 Gb and a somatic genome of ~3 Gb. We show that most of the excised DNA consists of repetitive sequences that are either 1) verifiable transposable elements (TEs), or 2) non-simple repeats of likely TE origin. Repeat elements in both genomes are skewed towards younger (i.e. less divergent) elements. Excised DNA is a non-random sample of the germline repeat element landscape; younger elements, and high frequency DNA transposons and LINEs, are disproportionately eliminated from the somatic genome. Conclusions Our results suggest that germline genome expansion in M. edax reflects explosive repeat element proliferation, and that billions of base pairs of such repeats are deleted from the somatic genome every generation. Thus, we hypothesize that chromatin diminution is a mechanism that controls repeat element load, and that this load can evolve to be divergent

  1. Hydrodynamics of Copepods: A Review

    NASA Astrophysics Data System (ADS)

    Jiang, Houshuo; Osborn, Thomas R.

    2004-07-01

    This paper reviews the hydrodynamics of copepods, guided by results obtained from recent theoretical and numerical studies of this topic to highlight the key concepts. First, we briefly summarize observational studies of the water flows (e.g., the feeding currents) created by copepods at their body scale. It is noticed that the water flows at individual copepod scale not only determine the net currents going around and through a copepod’s hair-bearing appendages but also set up a laminar flow field around the copepod. This laminar flow field interacts constantly with environmental background flows. Theoretically, we explain the creation of the laminar flow field in terms of the fact that a free-swimming copepod is a self-propelled body. This explanation is able to relate the various flow fields created by copepods to their complex swimming behaviors, and relevant results obtained from numerical simulations are summarized. Finally, we review the role of hydrodynamics in facilitating chemoreception and mechanoreception in copepods. As a conclusion, both past and current research suggests that the fluid mechanical phenomena occurring at copepod body scale play an important role in copepod feeding, sensing, swarming, mating, and predator avoidance.

  2. 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 34°49.5'N to 27°28.1'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

  3. 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.

  4. On the relation of structure, perception and activity in marine planktonic copepods

    NASA Astrophysics Data System (ADS)

    Paffenhöfer, G.-A.

    1998-06-01

    The goal of this paper is to illustrate how in juvenile and adult subtropical marine planktonic copepods various structures or morphological features function in concert to detect prey and predators. Without motion by either food (e.g. flagellate, ciliate) or feeder (e.g. feeding current) or both (e.g. Acartia spp. and ciliate) few feeding activities will occur. Through motion a food particle is either perceived mechanically or chemically to be followed by appendage activities. A combination of mechano- and chemosensors on their cephalic appendages (and probably on other extremities) serve juvenile and adult copepods to perceive signals. Perception is followed by alternation of motion and sensing by these appendages, or by no motion at all (e.g. behavior by Eucalanus pileatus when perceiving a weak hydrodynamic signal). Non-moving and extended sensors (setae) are best suited for mechanical/hydrodynamic perceptions in those copepods which lack a feeding current and hardly move. Numerous mechanosensors arranged in three dimensions on the first antennae (A1) are required to perceive the precise location of moving prey at a distance (e.g. Oithona feeding on ciliates but also sinking particles). Those copepods which create a weak or intermittent feeding current can supplement nutrition with carnivory, which requires perception by the A1 (e.g. Centropages velificatus adults). These two groups require, in addition to perception of prey motion/location, rapid motion by their appendages (A1, second maxillae M2, etc.) to capture the prey. Nauplii, which satiate at far lower food levels than adults, have one of several means of food acquisition: encounter through forward motion, perception through feeding current, or perception of a moving food particle. The nearly continuous motion of most calanoid nauplii makes them vulnerable to predation because all three pairs of appendages are usually moving. Opposite are nauplii of cyclopoid and a few calanoid species which move only

  5. 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

  6. 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.

  7. 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

  8. Internal Wave Apparatus for Copepod Behavior Assays

    NASA Astrophysics Data System (ADS)

    Jung, S.; Haas, K. A.; Webster, D. R.

    2015-11-01

    Internal waves are ubiquitous features in coastal marine environments and have been observed to mediate vertical distributions of zooplankton in situ. Internal waves are generated through oscillations of the pycnocline in stratified waters and thereby create fine-scale hydrodynamic cues that copepods and other zooplankton are known to sense, such as fluid density gradients and velocity gradients (quantified as shear deformation rate). The role of copepod behavior in response to cues associated with internal waves is largely unknown. Thus, a coupled quantification of copepod behavior and hydrodynamic cues will provide insight to the bio-physical interaction and the role of biological versus physical forcing in mediating organism distributions. We constructed a laboratory-scale internal wave apparatus to facilitate fine-scale observations of copepod behavior in flows that replicate in situ conditions of internal waves in a two-layer stratification. Three cases are chosen with density jump ranging between 0.75 - 1.5 kg/m3. Analytical analysis of the two-layer system provides guidance of the target forcing frequency to generate a standing internal wave with a single dominate frequency of oscillation. Flow visualization and signal processing of the interface location are used to quantify the wave characteristics. A copepod behavior assay is conducted, and sample trajectories are analyzed to identify copepod response to internal wave structure.

  9. 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

  10. 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

  11. 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. 

  12. 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

  13. Copepods and fishes in the Brazilian Amazon

    NASA Astrophysics Data System (ADS)

    Thatcher, Vernon E.

    1998-06-01

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

  14. 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.

  15. 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.

  16. 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

  17. Copepod Behavioral Response to Simulated Frontal Flows

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    When presented with a fine-scale upwelling or downwelling shear flow in a laboratory flume, two tropical copepods from the Red Sea, Acartia negligens and Clausocalanus furcatus, performed a set of behaviors that resulted in apparent depth-keeping and the potential for producing patchiness. Analyses of free-swimming trajectories revealed a behavioral threshold shear deformation rate value of 0.05 s-1 for both species. This threshold triggered statistically significant changes in path kinematics (i.e., relative swimming speed and turn frequency) in the shear layer versus out-of-layer. Gross path characteristics (i.e., net-to-gross displacement ratio, NGDR, and proportional vicinity time, PVT) were also significantly different in the shear layer treatments compared to controls. The vertical net-to-gross displacement ratio (VNGDR) was introduced here to explain a spectrum of depth-keeping behaviors. The mean value of VNGDR significantly increased in the shear layer treatments and, coupled with excited relative swimming speeds, suggested the potential to induce large vertical transport (at the 10 cm scale of the observation). However, histograms of VNGDR revealed a bimodality, which indicated a sizable portion of the population was also displaying depth-keeping behavior. Those copepod trajectories displaying large VNGDR predominately consisted of copepods swimming against the flow, thereby resisting vertical advection, which is another potential depth-keeping mechanism.

  18. A Lagrangian model of Copepod dynamics in turbulent flows

    NASA Astrophysics Data System (ADS)

    Ardeshiri, Hamidreza; Benkeddad, Ibtissem; Schmitt, Francois G.; Souissi, Sami; Toschi, Federico; Calzavarini, Enrico

    2016-04-01

    Planktonic copepods are small crustaceans that have the ability to swim by quick powerful jumps. Such an aptness is used to escape from high shear regions, which may be caused either by flow perturbations, produced by a large predator such as fish larave, or by the inherent highly turbulent dynamics of the ocean. Through a combined experimental and numerical study, we investigate the impact of jumping behaviour on the small-scale patchiness of copepods in a turbulent environment. Recorded velocity tracks of copepods displaying escape response jumps in still water are used to define and tune a Lagrangian Copepod (LC) model. The model is further employed to simulate the behaviour of thousands of copepods in a fully developed hydrodynamic turbulent flow obtained by direct numerical simulation of the Navier-Stokes equations. First, we show that the LC velocity statistics is in qualitative agreement with available experimental observations of copepods in turbulence. Second, we quantify the clustering of LC, via the fractal dimension D2. We show that D2 can be as low as 2.3, corresponding to local sheetlike aggregates, and that it critically depends on the shear-rate sensitivity of the proposed LC model. We further investigate the effect of jump intensity, jump orientation and geometrical aspect ratio of the copepods on the small-scale spatial distribution. Possible ecological implications of the observed clustering on encounter rates and mating success are discussed.

  19. Numerical simulation of a self-propelled copepod during escape

    NASA Astrophysics Data System (ADS)

    Sotiropoulos, Fotis; Borazjani, Iman; Malkiel, Edwin; Katz, Josef

    2008-11-01

    Obtaining the 3D flow field, forces, and power is essential for understanding the high accelerations of a copepod during the escap. We carry out numerical simulations to study a free swimming copepod using the sharp-interface immersed boundary, fluid-structure interaction (FSI) approach of Borazjani et al. (J Compu Phys, 2008, 227, p 7587-7620). We use our previous tethered copepod model with a realistic copepod-like body, including all the appendages with the appendages motion prescribed from high-resolution, cinematic dual digital holography. The simulations are performed in a frame of reference attached to the copepod whose velocity is calculated by considering the forces acting on the copepod. The self-propelled simulations are challenging due to the destabilizing effects of the large added mass resulting from the low copepod mass and fast acceleration during the escape. Strongly-coupled FSI with under-relaxation and the Aitken acceleration technique is used to obtain stable and robust FSI iterations. The computed results for the self-propelled model are analyzed and compared with our earlier results for the tethered model.

  20. 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.

  1. Molecular and microscopic evidence of viruses in marine copepods

    PubMed Central

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

    2013-01-01

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

  2. DNA Barcoding of Metazoan Zooplankton Copepods from South Korea

    PubMed Central

    Ryu, Shi Hyun; Kim, Sang Ki; Lee, Jin Hee; Lim, Young Jin; Lee, Jimin; Jun, Jumin; Kwak, Myounghai; Lee, Young-Sup; Hwang, Jae-Sam; Venmathi Maran, Balu Alagar; Chang, Cheon Young; Kim, Il-Hoi; Hwang, Ui Wook

    2016-01-01

    Copepods, small aquatic crustaceans, are the most abundant metazoan zooplankton and outnumber every other group of multicellular animals on earth. In spite of ecological and biological importance in aquatic environment, their morphological plasticity, originated from their various lifestyles and their incomparable capacity to adapt to a variety of environments, has made the identification of species challenging, even for expert taxonomists. Molecular approaches to species identification have allowed rapid detection, discrimination, and identification of cryptic or sibling species based on DNA sequence data. We examined sequence variation of a partial mitochondrial cytochrome C oxidase I gene (COI) from 133 copepod individuals collected from the Korean Peninsula, in order to identify and discriminate 94 copepod species covering six copepod orders of Calanoida, Cyclopoida, Harpacticoida, Monstrilloida, Poecilostomatoida and Siphonostomatoida. The results showed that there exists a clear gap with ca. 20 fold difference between the averages of within-specific sequence divergence (2.42%) and that of between-specific sequence divergence (42.79%) in COI, suggesting the plausible utility of this gene in delimitating copepod species. The results showed, with the COI barcoding data among 94 copepod species, that a copepod species could be distinguished from the others very clearly, only with four exceptions as followings: Mesocyclops dissimilis–Mesocyclops pehpeiensis (0.26% K2P distance in percent) and Oithona davisae–Oithona similis (1.1%) in Cyclopoida, Ostrincola japonica–Pseudomyicola spinosus (1.5%) in Poecilostomatoida, and Hatschekia japonica–Caligus quadratus (5.2%) in Siphonostomatoida. Thus, it strongly indicated that COI may be a useful tool in identifying various copepod species and make an initial progress toward the construction of a comprehensive DNA barcode database for copepods inhabiting the Korean Peninsula. PMID:27383475

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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

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

    PubMed

    Di Lorenzo, T; Di Marzio, W D; Sáenz, 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 μg l(-1), significantly lower than the HC computed

  11. 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

  12. Detecting in situ copepod diet diversity using molecular technique: development of a copepod/symbiotic ciliate-excluding eukaryote-inclusive PCR protocol.

    PubMed

    Hu, Simin; Guo, Zhiling; 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

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

    PubMed

    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

  14. Dissolution of coccolithophorid calcite by microzooplankton and copepod grazing

    NASA Astrophysics Data System (ADS)

    Antia, A. N.; Suffrian, K.; Holste, L.; Müller, 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.

  15. 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.

  16. 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

  17. Chemoreceptors and feeding in calanoid copepods (Arthropoda: Crustacea).

    PubMed Central

    Friedman, M M; Strickler, J R

    1975-01-01

    Ultrastructural studies of the mouthparts of the calanoid copepod Diaptomus pallidus have revealed the presence of numerous chemoreceptors, and the apparent absence of mechanoreceptors. The setae contain no muscles, and the setules are noncellular extensions of their chitin wall. This allows a new insight into the selective feeding of zooplankters. Images PMID:1060099

  18. Vibrio elicits targeted transcriptional responses from copepod hosts.

    PubMed

    Almada, Amalia A; Tarrant, Ann M

    2016-06-01

    Copepods are abundant crustaceans that harbor diverse bacterial communities, yet the nature of their interactions with microbiota are poorly understood. Here, we report that Vibrio elicits targeted transcriptional responses in the estuarine copepod Eurytemora affinis We pre-treated E. affinis with an antibiotic cocktail and exposed them to either a zooplankton specialist (Vibrio sp. F10 9ZB36) or a free-living species (Vibrio ordalii 12B09) for 24 h. We then identified via RNA-Seq a total of 78 genes that were differentially expressed following Vibrio exposure, including homologs of C-type lectins, chitin-binding proteins and saposins. The response differed between the two Vibrio treatments, with the greatest changes elicited upon inoculation with V. sp. F10 We suggest that these differentially regulated genes play important roles in cuticle integrity, the innate immune response, and general stress response, and that their expression may enable E. affinis to recognize and regulate symbiotic vibrios. We further report that V. sp. F10 culturability is specifically altered upon colonization of E. affinis These findings suggest that rather than acting as passive environmental vectors, copepods discriminately interact with vibrios, which may ultimately impact the abundance and activity of copepod-associated bacteria. PMID:27056917

  19. Converting copepod vital rates into units appropriate for biogeochemical models

    NASA Astrophysics Data System (ADS)

    Frangoulis, C.; Carlotti, F.; Eisenhauer, L.; Zervoudaki, S.

    2010-01-01

    The conversion of units is one of the difficulties of model parameterisation. Conversion errors may result not only from incorrect choices of conversion factors, but also from incorrect choices of the value itself. In biogeochemical models, mesozooplankton, is the highest trophic level of the food web, and it is very often reduced to a single variable generally considered as a representation of the copepod community, the dominant taxa in mesozooplankton. If this simplifies the information to be obtained for the stock, a correct parameterisation of the processes related to the copepod community is already a tricky task due to the wide range of copepod species, sizes, stages and behaviour. The goal of this paper is to improve the communication between experimentalists and modellers by giving indications for the conversion of copepod vital rates from experimental to biogeochemical model units. This includes the choice of values, conversion factors, terminology distinction and the scale transfer. To begin with, we briefly address the common problem of the conversion of a rate per individual to a rate per mass. Then, we focus on unit conversion problems for each specific rate and give recommendations. Finally, we discuss the problem of scale transfer between the level of organisation at which the rate value is measured at characteristic time and space-scales versus the level of representation of the corresponding process in the model, with its different characteristic time and space-scales .

  20. Copepod carcasses in a tropical estuary during different hydrographical settings.

    PubMed

    Jyothibabu, R; Jagadeesan, L; Lallu, K R

    2015-10-01

    Dead copepods (carcasses) are widespread in aquatic systems, but their scientific quantification is rare due to the difficulty in discriminating them from live ones. In this paper, we hypothesized that due to large spatial and temporal changes in hydrography in the Cochin backwaters, the percentage of copepod carcasses in the system could also change significantly on a spatial and temporal scale. In order to understand this aspect, we quantified the live and dead copepods in the Cochin backwaters under different hydrographical settings based on live and mortal staining technique. The most prominent temporal hydrographical feature during the study period was the large decline in salinity across the system, which was more pronounced downstream (15-20 units) and was caused by the large freshwater influx associated with the southwest monsoon. During the entire sampling period, copepod carcasses were pervasive all over the study area with large spatial and temporal variations in their percentage contribution (2.5-35.8 %) to the total community abundance. During all sampling, carcasses concentrated more in the downstream region, with maximum turbidity (16.5-35.8 %), than in the upstream region (2.5-14.5 %). The percentage of carcasses was the highest during the onset of the southwest monsoon (av. 23.64 ± 8.09 %), followed by the pre-southwest monsoon (av. 13.59 ± 6.72 %) and southwest monsoon (av. 8.75 ± 4.14 %). During the onset of the southwest monsoon, copepod carcasses in the downstream were contributed by ∼80 % high saline and ∼15 % low saline species, indicating a salinity shock-induced mortality. On the other hand, the cumulative effect of the long residence time of the Cochin backwaters and high partial predation rate of carnivores contributed to the high abundance of carcasses during the pre-monsoon. PMID:27614959

  1. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering and Chukchi seas

    NASA Astrophysics Data System (ADS)

    Sasaki, Hiroko; Matsuno, Kohei; Fujiwara, Amane; Onuka, Misaki; Yamaguchi, Atsushi; Ueno, Hiromichi; Watanuki, Yutaka; Kikuchi, Takashi

    2016-08-01

    The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed habitat models explaining the spatial patterns of large and small Arctic and Pacific copepods separately. Copepods were sampled using NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle component analysis scores, satellite-derived timing of sea ice retreat, bottom depth and chlorophyll a concentration were integrated into generalized additive models as explanatory variables. The adequate models for all copepods exhibited clear continuous relationships between the abundance of copepods and the indexed water masses. Large Arctic copepods were abundant at stations where the bottom layer was saline; however they were scarce at stations where warm fresh water formed the upper layer. Small Arctic copepods were abundant at stations where the upper layer was warm and saline and the bottom layer was cold and highly saline. In contrast, Pacific copepods were abundant at stations where the Pacific-origin water mass was predominant (i.e. a warm, saline upper layer and saline and a highly saline bottom layer). All copepod groups showed a positive relationship with early sea ice retreat. Early sea ice retreat has been reported to initiate spring blooms in open water, allowing copepods to utilize more food while maintaining their high activity in warm water without sea ice and cold water. This finding indicates that early sea ice retreat has positive effects on the abundance of all copepod groups in the northern Bering and Chukchi seas, suggesting a change from a pelagic-benthic-type ecosystem to a pelagic-pelagic type.

  2. 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

  3. 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 δ15N ratios, as compared to δ15N 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.

  4. 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

  5. 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

  6. 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

  7. The insidious effect of diatoms on copepod reproduction

    NASA Astrophysics Data System (ADS)

    Miralto, A.; Barone, G.; Romano, G.; Poulet, S. A.; Ianora, A.; Russo, G. L.; Buttino, I.; Mazzarella, G.; Laabir, M.; Cabrini, M.; Giacobbe, M. G.

    1999-11-01

    The productive regions of the ocean are characterized by seasonal blooms of phytoplankton which are generally dominated by diatoms. This algal class has, therefore, traditionally been regarded as providing the bulk of the food that sustains the marine food chain to top consumers and important fisheries. However, this beneficial role has recently been questioned on the basis of laboratory studies showing that although dominant zooplankton grazers such as copepods feed extensively on diatoms, the hatching success of eggs thus produced is seriously impaired. Here we present evidence from the field showing that the hatching success of wild copepods feeding on a diatom-dominated bloom is also heavily compromised, with only 12% of the eggs hatching compared with 90% in post-bloom conditions. We report on the structure of the three aldehydes isolated from diatoms that are responsible for this biological activity, and show that these compounds arrest embryonic development in copepod and sea urchin bioassays and have antiproliferative and apoptotic effects on human carcinoma cells.

  8. Hydrodynamics and energetics of jumping copepod nauplii and copepodids.

    PubMed

    Wadhwa, Navish; Andersen, Anders; Kiørboe, Thomas

    2014-09-01

    Within its life cycle, a copepod goes through drastic changes in size, shape and swimming mode. In particular, there is a stark difference between the early (nauplius) and later (copepodid) stages. Copepods inhabit an intermediate Reynolds number regime (between ~1 and 100) where both viscosity and inertia are potentially important, and the Reynolds number changes by an order of magnitude during growth. Thus we expect the life stage related changes experienced by a copepod to result in hydrodynamic and energetic differences, ultimately affecting the fitness. To quantify these differences, we measured the swimming kinematics and fluid flow around jumping Acartia tonsa at different stages of its life cycle, using particle image velocimetry and particle tracking velocimetry. We found that the flow structures around nauplii and copepodids are topologically different, with one and two vortex rings, respectively. Our measurements suggest that copepodids cover a larger distance compared to their body size in each jump and are also hydrodynamically quieter, as the flow disturbance they create attenuates faster with distance. Also, copepodids are energetically more efficient than nauplii, presumably due to the change in hydrodynamic regime accompanied with a well-adapted body form and swimming stroke. PMID:24948628

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

    NASA Astrophysics Data System (ADS)

    Raibaut, André; Combes, Claude; Benoit, Françoise

    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: taxonomy—fish families, genera and species; biometry—maximal size of the adult fish; eco-ethology—mode 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

  10. 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 (δ13C and δ15N) 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.

  11. 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...

  12. 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

  13. 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...

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

    NASA Astrophysics Data System (ADS)

    Van Nieuwerburgh, Lies; Wänstrand, 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.

  15. Macroevolutionary patterns of sexual size dimorphism in copepods.

    PubMed

    Hirst, Andrew G; Kiørboe, 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

  16. Feeding behavior of the poecilostomatoid copepods Oncaea spp. on chaetognaths

    NASA Astrophysics Data System (ADS)

    Go, You-Bong; Oh, Bong-Cheol; Terazaki, Makoto

    1998-06-01

    Feeding behaviors of the poecilostomatoid copepods Oncaea venusta, O. mediterranea and O. conifera were examined in the coastal area of Cheju Island, south of the Korean Peninsula, from April 1993 to November 1995. Late copepodid stages (CV, adult female and male) showed a high frequency of association with larger zooplankton such as Sagitta spp. (Chaetognatha), Oikopleura spp. (Appendicularia), and Salpa spp. (Thaliacea) in a coastal upwelling zone and around the small Munsum Island. Attack behaviors on Sagitta observed under the microscope and in the field showed that Oncaea approached Sagitta using their swimming legs, and then crawled chiefly to the neck regions and caudal septum (around the tail) of Sagitta spp. using their second antennae. They pierced the body of Sagitta with their sharp maxillipeds, and moved their maxillae and mandibles repeatedly. Midgut contents of Oncaea spp. consisted mainly of unidentified fine particles, and the greater part of the gut was empty. Their mouthpart structure is remarkably different from other pelagic copepods. Such differences of the mouthpart structures and the feeding habits in the genus Oncaea around Cheju Island are discussed in terms of feeding behavior and ecology in this coastal upwelling area.

  17. 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.

  18. 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 360×10-3 (with a density of 1 320 individuals/m3) and Arctodiaptomus salinus at salinity 300×10-3 (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.

  19. Lagrangian model of copepod dynamics: Clustering by escape jumps in turbulence

    NASA Astrophysics Data System (ADS)

    Ardeshiri, H.; Benkeddad, I.; Schmitt, F. G.; Souissi, S.; Toschi, F.; Calzavarini, E.

    2016-04-01

    Planktonic copepods are small crustaceans that have the ability to swim by quick powerful jumps. Such an aptness is used to escape from high shear regions, which may be caused either by flow perturbations, produced by a large predator (i.e., fish larvae), or by the inherent highly turbulent dynamics of the ocean. Through a combined experimental and numerical study, we investigate the impact of jumping behavior on the small-scale patchiness of copepods in a turbulent environment. Recorded velocity tracks of copepods displaying escape response jumps in still water are here used to define and tune a Lagrangian copepod (LC) model. The model is further employed to simulate the behavior of thousands of copepods in a fully developed hydrodynamic turbulent flow obtained by direct numerical simulation of the Navier-Stokes equations. First, we show that the LC velocity statistics is in qualitative agreement with available experimental observations of copepods in turbulence. Second, we quantify the clustering of LC, via the fractal dimension D2. We show that D2 can be as low as ˜2.3 and that it critically depends on the shear-rate sensitivity of the proposed LC model, in particular it exhibits a minimum in a narrow range of shear-rate values. We further investigate the effect of jump intensity, jump orientation, and geometrical aspect ratio of the copepods on the small-scale spatial distribution. At last, possible ecological implications of the observed clustering on encounter rates and mating success are discussed.

  20. 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.

  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. 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.

  3. 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.

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

    PubMed

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

    2012-11-01

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

  5. Lipid sac area as a proxy for individual lipid content of arctic calanoid copepods

    PubMed Central

    Vogedes, Daniel; Varpe, Øystein; Søreide, Janne E.; Graeve, Martin; Berge, Jørgen; Falk-Petersen, Stig

    2010-01-01

    We present an accurate, fast, simple and non-destructive photographic method to estimate wax ester and lipid content in single individuals of the calanoid copepod genus Calanus and test this method against gas-chromatographic lipid measurements. PMID:20824043

  6. 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).

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

    PubMed

    Voordouw, Maarten J; Anholt, Bradley R

    2002-09-01

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

  8. 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 (Rüppell) 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 (Forsskål). 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

  9. Improving ecological forecasts of copepod community dynamics using genetic algorithms

    NASA Astrophysics Data System (ADS)

    Record, N. R.; Pershing, A. J.; Runge, J. A.; Mayo, C. A.; Monger, B. C.; Chen, C.

    2010-08-01

    The validity of computational models is always in doubt. Skill assessment and validation are typically done by demonstrating that output is in agreement with empirical data. We test this approach by using a genetic algorithm to parameterize a biological-physical coupled copepod population dynamics computation. The model is applied to Cape Cod Bay, Massachusetts, and is designed for operational forecasting. By running twin experiments on terms in this dynamical system, we demonstrate that a good fit to data does not necessarily imply a valid parameterization. An ensemble of good fits, however, provides information on the accuracy of parameter values, on the functional importance of parameters, and on the ability to forecast accurately with an incorrect set of parameters. Additionally, we demonstrate that the technique is a useful tool for operational forecasting.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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 50 nm. 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 72 h exposure to 200 nM 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

  15. Response of marine copepods to a changing tropical environment: winners, losers and implications.

    PubMed

    Chew, Li Lee; Chong, Ving Ching

    2016-01-01

    Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the extent to which tropical copepods can adapt to rising temperature of already warm waters remains unknown. We hypothesize that sea warming and other anthropogenic disturbances over the long term will have the greatest impact on the copepod community in nearshore waters where their effects are accentuated, and therefore vulnerable and resilient species could be identified. Methods. Zooplankton samples were collected during two time periods (1985-86 and 2014-15) interposed by marked anthropogenic disturbances, and at the same five stations located progressively from inshore to offshore in Klang Strait, Malaysia, following the asymmetrical before-after-control-impact (BACI) design. Copepods were identified to species, and results were interpreted by univariate (ANOVA) and multivariate (PERMANOVA, PCO) analyses of the computed species abundance and diversity measures. Results. Copepod total abundance was not significantly different among stations but higher after disturbance than before disturbance. However, changes in the abundance of particular species and the community structure between time periods were dramatic. Coastal large-bodied calanoid species (e.g., Acartia spinicauda, Calanopia thompsoni, Pseudodiaptomus bowmani and Tortanus forcipatus) were the most vulnerable group to disturbance. This however favored the opportunistic species (e.g., Oithona simplex, O. attenuata, Hemicyclops sp., Pseudomacrochiron sp. and Microsetella norvegica). Small-bodied copepods (e.g., Paracalanus sp., Parvocalanus crassirostris and Euterpina acutifrons) were unaffected. Centropages

  16. Response of marine copepods to a changing tropical environment: winners, losers and implications

    PubMed Central

    Chew, Li Lee

    2016-01-01

    Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the extent to which tropical copepods can adapt to rising temperature of already warm waters remains unknown. We hypothesize that sea warming and other anthropogenic disturbances over the long term will have the greatest impact on the copepod community in nearshore waters where their effects are accentuated, and therefore vulnerable and resilient species could be identified. Methods. Zooplankton samples were collected during two time periods (1985–86 and 2014–15) interposed by marked anthropogenic disturbances, and at the same five stations located progressively from inshore to offshore in Klang Strait, Malaysia, following the asymmetrical before-after-control-impact (BACI) design. Copepods were identified to species, and results were interpreted by univariate (ANOVA) and multivariate (PERMANOVA, PCO) analyses of the computed species abundance and diversity measures. Results. Copepod total abundance was not significantly different among stations but higher after disturbance than before disturbance. However, changes in the abundance of particular species and the community structure between time periods were dramatic. Coastal large-bodied calanoid species (e.g., Acartia spinicauda, Calanopia thompsoni, Pseudodiaptomus bowmani and Tortanus forcipatus) were the most vulnerable group to disturbance. This however favored the opportunistic species (e.g., Oithona simplex, O. attenuata, Hemicyclops sp., Pseudomacrochiron sp. and Microsetella norvegica). Small-bodied copepods (e.g., Paracalanus sp., Parvocalanus crassirostris and Euterpina acutifrons) were unaffected. Centropages

  17. 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; 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

  18. 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.

  19. 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 α-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

  20. 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

  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. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-07-01

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

  4. Small copepods structuring mesozooplankton community dynamics in a tropical estuary-coastal system

    NASA Astrophysics Data System (ADS)

    Rakhesh, M.; Raman, A. V.; Ganesh, T.; Chandramohan, P.; Dehairs, F.

    2013-07-01

    It is important to know the ultimate role of small copepods in structuring mesozooplankton community pattern and diversity on an estuary-coastal gradient. Here multivariate analyses were used to elucidate this in the Godavari estuary, on the east coast of India. During May 2002, corresponding to the spring intermonsoon, mesozooplankton were sampled from 4 GPS fixed stations in the estuarine reaches of River Godavari and 19 in the coastal waters where Godavari enters the Bay of Bengal. There were 91 mesozooplankton taxa represented by 23 divergent groups. Copepods were by far the most prominent in terms of species richness, numerical abundance, and widespread distribution followed by appendicularians. Small copepods of families Paracalanidae, Acartiidae, Oithonidae, Corycaeidae, Oncaeidae, and Euterpinidae dominated. There were differing regional mesozooplankton/copepod communities, that segregated the estuary-coastal sites into different biotic assemblages: Group-I representing the estuary proper, Group-II estuary mouth and near shore, Group-III the intermediate coastal stations and Group-IV the coastal-offshore waters. Alpha (SRp, H', J', Δ*) and beta diversity (MVDISP, β, β-dissimilarity) measures varied noticeably across these assemblages/areas. The significant correlation of small copepod abundance with total mesozooplankton abundance and biomass (mgDM.m-3) in the estuarine (r: 0.40) and coastal (r: 0.46-0.83) waters together with a regression analysis of diversity measures have revealed the importance of small copepods in the overall mesozooplankton/copepod community structure. There were 'characterizing' and 'discriminating' species, responsible for the observed assemblage patterns. Mesozooplankton/copepod community structure and the size-spectra observed during this study indicate an estuarine-coastal gradient in plankton tropho-dynamics that may shift between a microbial dominated system inside the estuary and mixotrophy in the coastal waters. The

  5. Temporal Stability of Genetic Structure in a Mesopelagic Copepod.

    PubMed

    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

  6. 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

  7. Copepod Behavior in ``Cryptic Blooms'' of Toxic Algae

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    Copepods,Acartia tonsa and Temora longicornis, were exposed to thin layers of exudates from the toxic dinoflagellate Karenia brevis (1 - 10,000 cells/mL) (i.e. models of ``cryptic blooms'' of toxic phytoplankton). Planar laser-induced fluorescence (PLIF) was used to quantify the spatiotemporal structure of the layer allowing for correlation of behavioral responses with toxin levels. Both species explicitly avoided the exudate layer and the vicinity of the layer. Measures of path kinematics (swimming speed, turn frequency) by location (in-layer vs. out-of-layer) and exposure (pre-contact vs. post-contact) revealed some similarities, but also significant differences, in trends for each species. A. tonsa significantly increases swimming speed and swimming speed variability in the exudate layer and post-contact, whereas T. longicornis slightly increases both in-layer and slightly reduces both post-contact. Both species increase turn frequency in-layer and post-contact with increasing K. brevis exudate concentration. Path fracticality indicates that A. tonsatrajectories became more diffuse/sinuous and T. longicornis trajectories became more linear/ballistic (trending effects). Regression analyses revealed that the rate of change of behavior with increasing exudate concentration for A. tonsa was thrice to fifty times that of T. longicornis. Toxic K. brevis can essentially eliminate top-down grazer control ,another sinister means by which it gains a competitive advantage over the local phytoplankton taxa.

  8. 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.

  9. The Relationship between Phytoplankton Evenness and Copepod Abundance in Lake Nansihu, China.

    PubMed

    Tian, Wang; Zhang, Huayong; Zhao, Lei; Xu, Xiang; Huang, Hai

    2016-01-01

    The relationship between biodiversity and ecosystem functioning is a central issue in ecology. Previous studies have shown that producer diversity can impact the consumer community via predator-prey interactions. However, direct observations of this relationship remain rare, in particular for aquatic ecosystems. In this research, the relationship between phytoplankton diversity (species richness and evenness) and the abundance of copepods was analyzed in Lake Nansihu, a meso-eutrophic lake in China. The results showed that copepods abundance was significantly decreased with increasing phytoplankton evenness throughout the year. However, both species richness and phytoplankton biomass showed no significant relationship with the abundance of copepods. Canonical correspondence analysis revealed that phytoplankton evenness was negatively correlated with Thermocyclops kawamurai, Cyclops vicinus, Eucyclops serrulatus, Mesocyclops leuckarti, Sinocalanus tenellus, Sinocalanus dorrii, Copepods nauplius, but positively correlated with many Cyanophyta species (Chroococcus minutus, Dactylococcopsis acicularis, Microcystis incerta, Merismopedia tenuissima, Merismopedia sinica and Lyngbya limnetica). Based on our results, phytoplankton evenness was a better predictor of copepods abundance in meso-eutrophic lakes. These results provide new insights into the relationship between diversity and ecosystem functioning in aquatic ecosystems. PMID:27589782

  10. Turbulence triggers vigorous swimming but hinders motion strategy in planktonic copepods

    PubMed Central

    Michalec, François-Gaël; Souissi, Sami; Holzner, Markus

    2015-01-01

    Calanoid copepods represent a major component of the plankton community. These small animals reside in constantly flowing environments. Given the fundamental role of behaviour in their ecology, it is especially relevant to know how copepods perform in turbulent flows. By means of three-dimensional particle tracking velocimetry, we reconstructed the trajectories of hundreds of adult Eurytemora affinis swimming freely under realistic intensities of homogeneous turbulence. We demonstrate that swimming contributes substantially to the dynamics of copepods even when turbulence is significant. We show that the contribution of behaviour to the overall dynamics gradually reduces with turbulence intensity but regains significance at moderate intensity, allowing copepods to maintain a certain velocity relative to the flow. These results suggest that E. affinis has evolved an adaptive behavioural mechanism to retain swimming efficiency in turbulent flows. They suggest the ability of some copepods to respond to the hydrodynamic features of the surrounding flow. Such ability may improve survival and mating performance in complex and dynamic environments. However, moderate levels of turbulence cancelled gender-specific differences in the degree of space occupation and innate movement strategies. Our results suggest that the broadly accepted mate-searching strategies based on trajectory complexity and movement patterns are inefficient in energetic environments. PMID:25904528

  11. 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 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

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

    PubMed

    Tammilehto, Anna; Nielsen, Torkel Gissel; Krock, Bernd; Møller, 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

  13. 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 +4 °C, ambient -4 °C) 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

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

    PubMed

    Mieczan, Tomasz; Niedźwiecki, Michał; 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

  15. 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.; Örek, H.; Gucu, A. C.; Giannakourou, A.; Pitta, P.; Terbiyik, T.; Yϋcel, N.; Moutsopoulos, T.; Pagou, K.; Psarra, S.; Özsoy, 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.

  16. 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...

  17. Eco-friendly drugs from the marine environment: spongeweed-synthesized silver nanoparticles are highly effective on Plasmodium falciparum and its vector Anopheles stephensi, with little non-target effects on predatory copepods.

    PubMed

    Murugan, Kadarkarai; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Madhiyazhagan, Pari; Hwang, Jiang-Shiou; Wang, Lan; Dinesh, Devakumar; Suresh, Udaiyan; Roni, Mathath; Higuchi, Akon; Nicoletti, Marcello; Benelli, Giovanni

    2016-08-01

    Mosquitoes act as vectors of devastating pathogens and parasites, representing a key threat for millions of humans and animals worldwide. The control of mosquito-borne diseases is facing a number of crucial challenges, including the emergence of artemisinin and chloroquine resistance in Plasmodium parasites, as well as the presence of mosquito vectors resistant to synthetic and microbial pesticides. Therefore, eco-friendly tools are urgently required. Here, a synergic approach relying to nanotechnologies and biological control strategies is proposed. The marine environment is an outstanding reservoir of bioactive natural products, which have many applications against pests, parasites, and pathogens. We proposed a novel method of seaweed-mediated synthesis of silver nanoparticles (AgNP) using the spongeweed Codium tomentosum, acting as a reducing and capping agent. AgNP were characterized by UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). In mosquitocidal assays, the 50 % lethal concentration (LC50) of C. tomentosum extract against Anopheles stephensi ranged from 255.1 (larva I) to 487.1 ppm (pupa). LC50 of C. tomentosum-synthesized AgNP ranged from 18.1 (larva I) to 40.7 ppm (pupa). In laboratory, the predation efficiency of Mesocyclops aspericornis copepods against A. stephensi larvae was 81, 65, 17, and 9 % (I, II, III, and IV instar, respectively). In AgNP contaminated environment, predation was not affected; 83, 66, 19, and 11 % (I, II, III, and IV). The anti-plasmodial activity of C. tomentosum extract and spongeweed-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. Fifty percent inhibitory concentration (IC50) of C. tomentosum were 51.34 μg/ml (CQ-s) and 65.17 μg/ml (CQ-r); C. tomentosum-synthesized AgNP achieved IC50 of 72.45 μg/ml (CQ-s) and 76.08

  18. Sex ratio and reproductive activity of benthic copepods in bathyal Sagami Bay (1430 m), central Japan

    NASA Astrophysics Data System (ADS)

    Shimanaga, Motohiro; Shirayama, Yoshihisa

    2003-04-01

    Sex ratios and reproductive activity of benthic copepod assemblages were investigated at the bathyal site (depth 1430 m) in Sagami Bay, central Japan. The ratio of adult females to adult males was approximately 3.5:1, significantly different from 1:1, although this parameter did not show a seasonal pattern. On the other hand, the percentage of ovigerous females among adult females and the ratio of nauplii to total copepods appeared to fluctuate seasonally in 1997 and 1998. Statistical tests, however, could not detect significant difference in either parameter. We discuss the possibility that the reproductive activity of copepods was enhanced by the increased supply of fresh phytodetritus to the sea floor.

  19. 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 (6.9-17.7°C) 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

  20. Climate alters intraspecific variation in copepod effect traits through pond food webs.

    PubMed

    Charette, Cristina; Derry, Alison M

    2016-05-01

    Essential fatty acids (EFAs) are primarily generated by phytoplankton in aquatic ecosystems, and can limit the growth, development, and reproduction of higher consumers. Among the most critical of the EFAs are highly unsaturated fatty acids (HUFAs), which are only produced by certain groups of phytoplankton. Changing environmental conditions can alter phytoplankton community and fatty acid composition and affect the HUFA content of higher trophic levels. Almost no research has addressed intraspecific variation in HUFAs in zooplankton, nor intraspecific relationships of HUFAs with body size and fecundity. This is despite that intraspecific variation in HUFAs can exceed interspecific variation and that intraspecific trait variation in body size and fecundity is increasingly recognized to have an important role in food web ecology (effect traits). Our study addressed the relative influences of abiotic selection and food web effects associated with climate change on intraspecific differences and interrelationships between HUFA content, body size, and fecundity of freshwater copepods. We applied structural equation modeling and regression analyses to intraspecific variation in a dominant calanoid copepod, Leptodiatomus minutus, among a series of shallow north-temperate ponds. Climate-driven diurnal temperature fluctuations favored the coexistence of diversity of phytoplankton groups with different temperature optima and nutritive quality. This resulted in unexpected positive relationships between temperature, copepod DHA content and body size. Temperature correlated positively with diatom biovolume, and mediated relationships between copepod HUFA content and body size, and between copepod body size and fecundity. The presence of brook trout further accentuated these positive effects in warm ponds, likely through nutrient cycling and stimulation of phytoplankton resources. Climate change may have previously unrecognized positive effects on freshwater copepod DHA content

  1. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

    PubMed

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

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts. PMID:27224476

  2. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content

    PubMed Central

    Hansen, Thomas; Ismar, Stefanie M. H.; Sommer, Ulrich

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1–5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts. PMID:27224476

  3. 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.

  4. Life cycle strategies of epipelagic copepods in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Atkinson, Angus

    1998-06-01

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

  5. 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.

  6. 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

  7. 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 α,β,γ,δ-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

  8. 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

  9. 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

  10. 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

  11. 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 α,β,γ,δ-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

  12. 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

  13. 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.

  14. Life in the extreme environment at a hydrothermal vent: haemoglobin in a deep-sea copepod.

    PubMed Central

    Sell, A F

    2000-01-01

    This is the first study, to my knowledge, quantifying the respiratory pigment haemoglobin discovered in a deep-sea copepod. Haemoglobin in copepods has previously been documented in only one other species from the deep water of an Italian lake. Specimens of the siphonostomatoid Scotoecetes introrsus Humes were collected during submersible dives at 2500 m depth near a hydrothermal vent at the East Pacific Rise (9 degrees N). The haemoglobin content in the copepods' haemolymph was 4.3 +/- 0.6 micrograms per individual female (n = 6) and 1.8 +/- 0.1 micrograms per individual male (n = 6). Weight-specific concentrations of haemoglobin were identical for females and males (0.25 +/- 0.04 and 0.26 +/- 0.02 microgram per microgram dry weight, respectively). These haemoglobin concentrations are higher than those found in other small crustaceans. Activity of the electron transport system indicated that the respiration rates in S. introrsus (13.7 +/- 7.7 microliters O2 per milligram dry weight per hour) were similar to those in the shallow-water copepod Acartia tonsa (9.1 +/- 1.3 microliters O2 per milligram dry weight per hour). It was concluded that the possession of highly concentrated haemoglobin allows S. introrsus to colonize a geologically young, thermally active site such as the vicinity of a hydrothermal vent, despite the prevailing oxygen depletion. PMID:11413650

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. The use of chlorine dioxide for the inactivation of copepod zooplankton in drinking water treatment.

    PubMed

    Lin, Tao; Chen, Wei; Cai, Bo

    2014-01-01

    The presence of zooplankton in drinking water treatment system may cause a negative effect on the aesthetic value of drinking water and may also increase the threat to human health due to they being the carriers of bacteria. Very little research has been done on the effects of copepod inactivation and the mechanisms involved in this process. In a series of bench-scale experiments we used a response surface method to assess the sensitivity of copepod to inactivation when chlorine dioxide (ClO₂) was used as a disinfectant. We also assessed the effects of the ClO₂dosage, exposure time, organic matter concentration and temperature. Results indicated that the inactivation rate improved with increasing dosage, exposure time and temperature, whereas it decreased with increasing organic matter concentration. Copepod inactivation was more sensitive to the ClO₂dose than that to the exposure time, while being maintained at the same Ct-value conditions. The activation energy at different temperatures revealed that the inactivation of copepods with ClO₂was temperature-dependent. The presence of organic matter resulted in a lower available dose as well as a shorter available exposure time, which resulted in a decrease in inactivation efficiency. PMID:25176489

  2. Calanoid Copepod Behavior in Thin Layer Shear Flows: Freshwater Versus Marine

    NASA Astrophysics Data System (ADS)

    Skipper, A. N.; Webster, D. R.; Yen, J.

    2015-11-01

    Marine copepods have been shown to behaviorally respond to vertical gradients of horizontal velocity and aggregate around thin layers. The current study addresses whether a freshwater copepod from an alpine lake demonstrates similar behavior response. Hesperodiaptomus shoshone is often the greatest biomass in alpine lakes and is the dominant zooplankton predator within its environment. The hypothesis is that H. shoshone responds to vertical gradients of horizontal velocity, which are associated with river outflows from alpine lakes, with fine-scale changes in swimming kinematics. The two calanoid copepods studied here, H. shoshone (freshwater) and Calanus finmarchicus(marine), are of similar size (2 - 4 mm), have similar morphologies, and utilize cruising as their primary swimming mode. The two animals differ not only in environment, but also in diet; H. shoshone is a carnivore, whereas C. finmarchicusis an herbivore. A laminar, planar jet (Bickley) was used in the laboratory to simulate a free shear flow. Particle image velocimetry (PIV) quantified the flow field. The marine species changed its swimming behavior significantly (increased swimming speed and turning frequency) and spent more time in the layer (40% vs. 70%) from control to treatment. In contrast, the freshwater species exhibited very few changes in either swimming behavior or residence time. Swimming kinematics and residence time results were also similar between males and females. Unlike the marine copepod, the results suggest the environmental flow structure is unimportant to the freshwater species.

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

    PubMed

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

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. Factors controlling the summer development of copepod populations in the southern bight of the North Sea

    NASA Astrophysics Data System (ADS)

    Daan, Rogier

    In two consecutive years an intensive sampling programmed was implemented at a fixed station in Dutch coastal waters to obtain a detailed record of the summer development of copepod populations in relation to phytoplankton and macroplankton abundance. The central question was whether densities of copepods are controlled by predation, in particular by invertebrate pelagic carnivores, or by food limitation. Methods applied to estimate daily predation by observed stocks of carnivores included analysis of gut contents and digestion rate, extrapolation of experimental feeding rates and of literature data on daily rations and maintenance needs. Chlorophyll- a and cell concentrations served as a rough measure for algal food supply. Since a decline in copepod densities manifested itself most clearly in decreasing naupliar numbers in both years, populations were assumed to be regulated mainly by recruitment or survival of these early life stages. Naupliar declines coincided with maximum densities of the hydromedusa Phialidium hemisphaericum, which dominated the macroplankton both in abundance and in biomass and reached a maximum density of 467 specimens·m -3 or 7 mg C·m -3. Copepod eggs appeared by far the most frequent prey item in their guts. However, these eggs are digested very slowly, if at all, and may often be ejected without any visible damage. The effect of egg predation on naupliar recruitment seems therefore relatively unimportant. Predation on swimming copepod stages was generally low. There was no evidence of selective feeding on nauplii. The maximum values of calculated predation pressure exerted by Phialidium populations matched daily copepod production only by way of exception. Impact of other invertebrate carnivores was negligible. As predation did not play a significant role, food availability seems the key factor underlying copepod population dynamics. The consequences of food limitation (reduced egg production, production of diapause eggs and enhanced

  9. 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 (7°C), July (15.5°C) and September (17°C). In July and September labile POC concentrations were low (44 and 77 mg·m -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

  10. 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

  11. 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 μm. 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

  12. 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 μm. 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

  13. 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.

  14. Non-limiting food conditions for growth and production of the copepod community in a highly productive upwelling zone

    NASA Astrophysics Data System (ADS)

    Escribano, Rubén; Bustos-Ríos, Evelyn; Hidalgo, Pamela; Morales, Carmen E.

    2016-09-01

    Zooplankton production is critical for understanding marine ecosystem dynamics. This work estimates copepod growth and production in the coastal upwelling and coastal transition zones off central-southern Chile (~35 to 37°S) during a 3-year time series (2004, 2005, and 2006) at a fixed shelf station, and from spring-summer spatial surveys during the same period. To estimate copepod production (CP), we used species-biomasses and associated C-specific growth rates from temperature dependent equations (food-saturated) for the dominant species, which we assumed were maximal growth rates (gmax). Using chlorophyll-a concentrations as a proxy for food conditions, we determined a size-dependent half-saturation constant with the Michaelis-Menten equation to derive growth rates (g) under the effect of food limitation. These food-dependent C-specific growth rates were much lower (<0.1 d-1) than those observed in the field for the dominant species, while gmax for same species, in the range of 0.19-0.23 d-1 better represented the necessary growth to attain observed adult sizes of at least two copepods, Paracalanus cf. indicus and Calanus chilensis. Copepod biomass (CB) and rates of maximal copepod production (CPmax) obtained with gmax were higher in the coastal upwelling zone (<50 km from shore), and correlated significantly to oceanographic variables associated with upwelling conditions. Both CPmax and gmax exhibited negative trends at the fixed station from 2004 to 2006 in association with increased duration of upwelling in the latter year. Annual CPmax ranged between 24 and 52 g C m-2 y-1 with a mean annual P/B ratio of 7.3. We concluded that interannual variation in copepod production resulted from factors and processes regulating copepod abundance and biomass in the absence of bottom-up control, allowing copepods to grow without limitation due to food resources.

  15. 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.

  16. 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

  17. 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

  18. 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 (∼75-78°N; 77-69°W). 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

  19. 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.

  20. 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

  1. Transcriptomic responses of the calanoid copepod Calanus finmarchicus to the saxitoxin producing dinoflagellate Alexandrium fundyense

    PubMed Central

    Roncalli, Vittoria; Cieslak, Matthew C.; Lenz, Petra H.

    2016-01-01

    In the Gulf of Maine, the copepod Calanus finmarchicus co-occurs with the neurotoxin-producing dinoflagellate, Alexandrium fundyense. The copepod is resistant to this toxic alga, but little is known about other effects. Gene expression profiles were used to investigate the physiological response of females feeding for two and five days on a control diet or a diet containing either a low or a high dose of A. fundyense. The physiological responses to the two experimental diets were similar, but changed between the time points. At 5-days the response was characterized by down-regulated genes involved in energy metabolism. Detoxification was not a major component of the response. Instead, genes involved in digestion were consistently regulated, suggesting that food assimilation may have been affected. Thus, predicted increases in the frequency of blooms of A. fundyense could affect C. finmarchicus populations by changing the individuals’ energy budget and reducing their ability to build lipid reserves. PMID:27181871

  2. 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

  3. Transcriptomic responses of the calanoid copepod Calanus finmarchicus to the saxitoxin producing dinoflagellate Alexandrium fundyense.

    PubMed

    Roncalli, Vittoria; Cieslak, Matthew C; Lenz, Petra H

    2016-01-01

    In the Gulf of Maine, the copepod Calanus finmarchicus co-occurs with the neurotoxin-producing dinoflagellate, Alexandrium fundyense. The copepod is resistant to this toxic alga, but little is known about other effects. Gene expression profiles were used to investigate the physiological response of females feeding for two and five days on a control diet or a diet containing either a low or a high dose of A. fundyense. The physiological responses to the two experimental diets were similar, but changed between the time points. At 5-days the response was characterized by down-regulated genes involved in energy metabolism. Detoxification was not a major component of the response. Instead, genes involved in digestion were consistently regulated, suggesting that food assimilation may have been affected. Thus, predicted increases in the frequency of blooms of A. fundyense could affect C. finmarchicus populations by changing the individuals' energy budget and reducing their ability to build lipid reserves. PMID:27181871

  4. 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.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Escribano, R.; Bustos-Ríos, 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.

  7. Influence of Kuroshio water on the annual copepod community structure in an estuary in the northwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Tseng, Li-Chun; Hsiao, Shih-Hui; Sarkar, Santosh Kumar; Bhattacharya, Bhaskar Deb; Chen, Qing-Chao; Hwang, Jiang-Shiou

    2016-04-01

    The influence of Kuroshio water on temporal distribution and copepod diversity was investigated in the Lanyang River estuary (LRE), the longest river in northeast Taiwan, to assess secondary productivity. Zooplankton samples were collected bimonthly from the surface waters (0-2 m) of the estuary during cruises in 2006. Hydrological parameters indicated that the water in the LRE was an admixture of the Lanyang River water and seawater. Among the different genera, 47 copepod species (including 10 species that were identified only to the generic level) belonging to 28 genera, 16 families, and 4 orders were identified. The abundance and proportion of copepods to the total zooplankton counts range from 0 to 3683.42 (304.9±692.7 individuals m-3) and from 0 to 100 (55.09±34.84%) respectively. The copepod community structure revealed a distinct seasonal succession and showed significant differences among the sampling cruises (p<0.05, One-way ANOVA). The 5 most abundant species were Parvocalanus crassirostris (relative abundance [RA]: 50.93%), Pseudodiaptomus serricaudatus (RA: 16.85%), Euterpina acutifrons (RA: 7.34%), Cyclops vicinus (RA: 4.82%), and Microcyclops tricolor (RA: 3.15%). The abundance, species number, indices of richness, evenness, and copepod diversity varied significantly (p<0.05, One-way ANOVA) for all the cruises. Pearson correlation analysis results demonstrated that salinity was positively correlated with the copepod species number (r=0.637), total copepod abundance (r=0.456), and Shannon-Wiener diversity index (r=0.375) with a 1% level of significance. By contrast, the evenness index was negatively correlated with salinity (r=-0.375, p=0.01), indicating that copepod diversity in the LRE was influenced mainly by seawater. The Kuroshio Current played a major role in transporting and distributing warm-water copepods to its affected area. Copepod species assemblages showed seasonal succession and varied drastically with tidal change. The latter

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. Sublethal exposure to crude oil enhances positive phototaxis in the calanoid copepod Calanus finmarchicus.

    PubMed

    Miljeteig, Cecilie; Olsen, Anders Johny; Nordtug, Trond; Altin, Dag; Jenssen, Bjørn Munro

    2013-12-17

    We investigated the effects of exposure to sublethal concentrations of the water accommodated fraction (WAF) of fresh crude oil on phototactic behavior of the calanoid copepod Calanus finmarchicus (Gunnerus) copepodite stage 5 (C5). Exposure was conducted in closed bottle systems, and behavior was tested in a tailored setup. Exposure times were 24, 48, 72, and 96 h, and the chosen exposure concentration was 25% of the recorded LC50 value for the WAF (309 ± 32 μg/L total hydrocarbon, including 20.37 ± 0.51 μg/L total PAH). The exposure significantly increased the positive phototactic behavior of the copepods after 24 h exposure and a similar significant effect was observed for all exposure durations. Additionally, experiments were conducted with nonexposed copepods with low lipid reserves. The main effect of the exposure was a shift in the response to light toward a more positive phototaxis, similar to that observed in nonexposed C. finmarchicus with low lipid reserves. The observed change in phototactic behavior observed in these studies suggests that the depth distribution of this species could be altered following an oil spill. Thus, further research is warranted to determine the possible interactive effects of light and oil spill exposures on Calanus population dynamics under field conditions. PMID:24219329

  13. Habitat temperature is an important determinant of cholesterol contents in copepods

    PubMed Central

    Hassett, R. Patrick; Crockett, Elizabeth L.

    2009-01-01

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

  14. Label-free microscopy and stress responses reveal the functional organization of Pseudodiaptomus marinus copepod myofibrils.

    PubMed

    Ibrahim, Ali; Hage, Charles Henri; Souissi, Anissa; Leray, Aymeric; Héliot, Laurent; Souissi, Sami; Vandenbunder, Bernard

    2015-08-01

    Pseudodiaptomus marinus copepods are small crustaceans living in estuarine areas endowed with exceptional swimming and adaptative performances. Since the external cuticle acts as an impermeable barrier for most dyes and molecular tools for labeling copepod proteins with fluorescent tags are not available, imaging cellular organelles in these organisms requires label free microscopy. Complementary nonlinear microscopy techniques have been used to investigate the structure and the response of their myofibrils to abrupt changes of temperature or/and salinity. In contrast with previous observations in vertebrates and invertebrates, the flavin autofluorescence which is a signature of mitochondria activity and the Coherent Anti-Stokes Raman Scattering (CARS) pattern assigned to T-tubules overlapped along myofibrils with the second harmonic generation (SHG) striated pattern generated by myosin tails in sarcomeric A bands. Temperature jumps from 18 to 4 °C or salinity jumps from 30 to 15 psu mostly affected flavin autofluorescence. Severe salinity jumps from 30 to 0 psu dismantled myofibril organization with major changes both in the SHG and CARS patterns. After a double stress (from 18 °C/30 psu to 4° C/0 psu) condensed and distended regions appeared within single myofibrils, with flavin autofluorescence bands located between sarcomeric A bands. These results shed light on the interactions between the different functional compartments which provide fast acting excitation-contraction coupling and adequate power supply in copepods muscles. PMID:26057347

  15. Comparison of Turbulence-Copepod Interaction: Temora longicornis vs. Acartia tonsa

    NASA Astrophysics Data System (ADS)

    de Jesus-Villanueva, N. H.; Young, D. L.; Webster, D. R.; Yen, J.

    2014-11-01

    The purpose of this study is to examine the behavioral response of the marine copepod Temora longicornisto 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. Copepod behavioral assays were conducted for two turbulence levels corresponding to mean turbulent dissipation rates of 0.009 (Level 2) and 0.096 (Level 3) cm2/s3. The Burgers' vortex parameters (i.e., circulation and axial strain rate) are specified to match a vortex corresponding to the median viscous dissipation rate for each target turbulence level. The behavioral response of T. longicornis compared to Acartia tonsa is of particular interest due to differences in swim style (cruiser vs. hop-sinker, respectively) and mechanosensory array morphology (planar vs. 3D, respectively). When exposed to these vortex flow treatments, T. longicornis exhibited a minimal behavioral response to the Level 2 vortex, but significantly altered their swimming behavior in the presence of the Level 3 vortex. Specifically, in the Level 3 vortex treatment T. longicornis increased relative swim speed, turn frequency, and escape acceleration while decreasing angle of alignment with the vortex axis and escape frequency (relative to stagnant control conditions). Histograms of escape jump location as a function of radius reveals no preferential escape location for T. longicornis, which contrasts the preferential escape location of A. tonsa in the vortex core.

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

    USGS Publications Warehouse

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

    2002-01-01

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

  17. Differential protein expression in the estuarine copepod Eurytemora affinis after diuron and alkylphenol exposures.

    PubMed

    Boulangé-Lecomte, Céline; Rocher, Béatrice; Cailleaud, Kévin; Cosette, Pascal; Legrand, Eléna; Devreker, David; Budzinski, Hélène; Souissi, Sami; Forget-Leray, Joëlle

    2016-07-01

    Proteomics was used in the calanoid copepod Eurytemora affinis for screening of protein expression modifications induced by organic contaminants. The copepods were exposed in a continuous flow-through system for 86 h to environmentally relevant concentrations of contaminants representative of the pollution in the Seine Estuary (Haute-Normandie, France; diuron, 500 ng L(-1) ; alkylphenol mixture, 1000 ng L(-1) ). Proteome analysis of whole-body copepod extracts by 2-dimensional gel electrophoresis revealed that the contaminants induced modifications in protein expression, with the highest quantitative variations occurring after diuron exposure. Specifically, 88 and 41 proteins were differentially expressed after diuron and alkylphenol treatments, respectively. After mass spectrometry analysis, 51 (diuron exposure) and 15 (alkylphenol exposure) proteins were identified. The identified proteins were potentially related to energy metabolism, cell growth, nervous signal conductivity, excitotoxicity, oxidative stress response, and antioxidant defense. The data suggest a massive general disturbance of physiological functions of E. affinis after diuron exposure, whereas alkylphenols induced an alteration of a few targeted physiological functions. The protein expression signatures identified after contaminant exposure deserve further investigation in terms of the development of novel potential biomarkers for water quality assessment. Environ Toxicol Chem 2016;35:1860-1871. © 2015 SETAC. PMID:26677818

  18. The effects of a parasitic copepod on the recent larval growth of a fish inhabiting rocky coasts.

    PubMed

    Palacios-Fuentes, Pamela; Landaeta, Mauricio F; Muñoz, Gabriela; Plaza, Guido; Ojeda, F Patricio

    2012-10-01

    Parasites can infect larval, juvenile or adult marine fishes; however, the effects of parasites on the growth and condition of fish larvae have seldom been investigated. This study analysed the effects of a parasitic copepod on the larval growth of the Chilean triplefin Helcogrammoides chilensis (Tripterygiidae) based on the microstructure of the sagittal otoliths. Fish larvae were collected during the austral spring of 2010 off central Chile. Their body length ranged from 5.1 to 16.6 mm (2 to 57 days old). They were parasitised by a penellid larval copepod that was always externally attached to the ventral side of the fish's gut. The prevalence of the copepod ranged from 2.7% to 20.8%, with one to four parasites per fish larva. Relationships between otolith size (radius, perimeter) and larval size were equal for parasitised and unparasitised fish larvae (P > 0.05). Larval growth was also similar for unparasitised (0.21 mm/day) and parasitised fish larvae (0.19 mm/day) (P > 0.05). However, a comparison of same-aged larvae showed that the larvae with copepods were smaller in both length and estimated body volume than the larvae without copepods. The Recent Otolith Growth Index, indicated that larval H. chilensis with copepods showed a reduction in recent growth and condition compared with those without evidence of copepods (P < 0.05). Nevertheless, a higher parasite load (two vs. one pennellids) did not decrease the condition of the larval fish. The infestation of pennellids on coastal fish larvae may therefore induce an increase in the pelagic larval duration and potentially affect the settlement rates of this intertidal fish. PMID:22752746

  19. 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

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

    PubMed Central

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

    1998-01-01

    Within laboratory-induced swarms of the marine copepod Temora longicornis, the male exhibits chemically mediated trail-following behaviour, concluding with fluid mechanical provocation of the mate-capture response. The location and structure of the invisible trail were determined by examining the specific behaviour of the female copepods creating the signal, the response of the male to her signal, and the fluid physics of signal persistence. Using the distance of the mate-tracking male from the ageing trail of the female, we estimated that the molecular diffusion coefficient of the putative pheromonal stimulant was 2.7 x 10(-5) cm2 s-1, or 1000 times slower than the diffusion of momentum. Estimates of signal strength levels, using calculations of diffusive properties of odour trails and attenuation rates of fluid mechanical signals, were compared to the physiological and behavioural threshold detection levels. Males find trails because of strong across-plume chemical gradients; males sometimes go the wrong way because of weak along-plume gradients; males lose the trail when the female hops because of signal dilution; and mate-capture behaviour is elicited by suprathreshold flow signals. The male is stimulated by the female odour to accelerate along the trail to catch up with her, and the boundary layer separating the signal from the chemosensitive receptors along the copepod antennule thins. Diffusion times, and hence reaction times, shorten and behavioural orientation responses can proceed more quickly. While 'perceptive' distance to the odour signal in the trail or the fluid mechanical signal from the female remains within 1-2 body lengths (< 5 mm), the 'reactive' distance between males and females was an order of magnitude larger. Therefore, when nearest-neighbour distances are 5 cm or less, as in swarms of 10(4) copepods m-3, mating events are facilitated. The strong similarity in the structure of mating trails and vortex tubes (isotropic, millimetre

  1. 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 μg/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

  2. 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

  3. Control of diapause by acidic pH and ammonium accumulation in the hemolymph of Antarctic copepods.

    PubMed

    Schründer, 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

  4. 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

  5. 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.

  6. Response of Copepods to Elevated pCO2 and Environmental Copper as Co-Stressors – A Multigenerational Study

    PubMed Central

    Fitzer, Susan C.; Caldwell, Gary S.; Clare, Anthony S.; Upstill-Goddard, Robert C.; Bentley, Matthew G.

    2013-01-01

    We examined the impacts of ocean acidification and copper as co-stressors on the reproduction and population level responses of the benthic copepod Tisbe battagliai across two generations. Naupliar production, growth, and cuticle elemental composition were determined for four pH values: 8.06 (control); 7.95; 7.82; 7.67, with copper addition to concentrations equivalent to those in benthic pore waters. An additive synergistic effect was observed; the decline in naupliar production was greater with added copper at decreasing pH than for decreasing pH alone. Naupliar production modelled for the two generations revealed a negative synergistic impact between ocean acidification and environmentally relevant copper concentrations. Conversely, copper addition enhanced copepod growth, with larger copepods produced at each pH compared to the impact of pH alone. Copepod digests revealed significantly reduced cuticle concentrations of sulphur, phosphorus and calcium under decreasing pH; further, copper uptake increased to toxic levels that lead to reduced naupliar production. These data suggest that ocean acidification will enhance copper bioavailability, resulting in larger, but less fecund individuals that may have an overall detrimental outcome for copepod populations. PMID:23951121

  7. 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

  8. Patterns in diversity and community structure of epipelagic copepods from the Brazil Malvinas Confluence area, south-western Atlantic

    NASA Astrophysics Data System (ADS)

    Berasategui, A. D.; Ramírez, F. C.; Schiariti, A.

    2005-06-01

    Diversity and structure of epipelagic copepod communities were investigated using 70 zooplankton samples collected from the top 50 m of the Brazil-Malvinas Confluence area between 35° and 55°S. Biogeographic patterns were investigated using multivariate analysis. Biodiversity patterns were examined using different univariate indexes. Representatives of 35 species of copepods from 23 genera and 13 families were found. Two zones were delimited based on their copepod composition, one in the subtropical waters of the Brazil current, and the other in the subantarctic waters of the Malvinas current. Both environments displayed contrasting patterns of biodiversity depending upon which element is measured (regional species richness as well as mean point species richness were significantly higher in the subtropical group of stations, whereas taxonomic distinctness was significantly higher in the subantarctic community). Based on these contrasting results, we suggest the use of both kind of indexes when defining priority areas for conservation.

  9. 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

  10. An enzyme-linked immunosorbent assay for lipovitellin quantification in copepods: a screening tool for endocrine toxicity.

    PubMed

    Volz, David C; Chandler, G Thomas

    2004-02-01

    Vitellogenin (VTG) has been widely used as a biomarker of estrogenic exposure in fish, leading to the development of standardized assays for VTG quantification. However, standardized quantitative assays for invertebrate, particularly crustacean, lipovitellin (also known as vitellin [VTN]) are lacking. In this study, a fluorescence-based VTN enzyme-linked immunosorbent assay (ELISA) was developed to quantify microquantities of VTN in the estuarine, sediment-dwelling copepod Amphiascus tenuiremis. This ELISA utilizes a VTN-specific polyclonal antibody developed against amphipod (Leptocheirus plumulosus) embryo VTN and exhibits specificity toward female copepod proteins. In routine assays, the working range of the ELISA was 31.25 to 1,000 ng/ml (75-25% specific binding/maximum antibody binding [B/B0]) with a 50% B/B0 intra- and interassay variation of 3.9% (n = 9) and 12.5% (n = 26), respectively. This ELISA is capable of detecting VTN as low as 2 ng/ml, and can accurately detect VTN in as few as four copepods. The ELISA significantly discriminated positive (gravid female) and negative (male) samples, and was suitable for screening endocrine toxicity in copepods. Stage-I juvenile copepods were individually reared to adults in aqueous microvolumes of the phenylpyrazole insecticide, fipronil, and whole-body homogenate extracts were assayed for VTN levels. Fipronil-exposed virgin adult females, but not males, exhibited significantly higher levels of VTN relative to control males and females. This crustacean VTN ELISA is likely useful for evaluating endocrine activity of environmental toxicants in copepods and other crustacean species. PMID:14982375

  11. 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

  12. 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 µmol 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

  13. 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

  14. 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

  15. 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 (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 µmol 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

  16. 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

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

    PubMed

    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

  18. 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

  19. 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

  20. From local adaptation to ecological speciation in copepod populations from neighboring lakes.

    PubMed

    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

  1. Acute toxicity testing with the tropical marine copepod Acartia sinjiensis: optimisation and application.

    PubMed

    Gissi, F; Binet, M T; Adams, M S

    2013-11-01

    Globally there is limited toxicity data for tropical marine species, and there has been a call for further research and development in the area of tropical marine ecotoxicology. An increase in developmental pressures in northern tropical Australia is causing a higher demand for toxicity test protocols with ecologically relevant species. Copepods are a diverse group of zooplankton that are major components of marine food webs. The calanoid copepod Acartia sinjiensis is widely distributed across tropical and sub-tropical brackish to marine waters of Australia and was identified in a recent comprehensive review of marine tropical toxicity testing in Australia as a suitable test organism. Through a number of optimisation steps including feeding trials, changes to culture and test conditions; a 48-h acute toxicity test with A. sinjiensis was modified to become a highly reliable and reproducible standard test protocol. Control mobility was improved significantly, and the sensitivity of A. sinjiensis to copper (EC50 of 33µg/L), ammonia (EC50 of 10mg/L) and phenol (EC50 of 13mg/L) fell within the ranges of those reported previously, indicating that the modifications did not alter its sensitivity. In a comprehensive literature search we found that this species was the most sensitive to copper out of a range of marine copepods. The test was also successfully applied in toxicity assessments of four environmental samples: two produced formations waters (PFWs) and two mine tailing liquors (MTLs). The toxicity assessments utilised toxicity data from a suite of marine organisms (bacteria, microalgae, copepods, sea urchins, oysters, prawns, and fish). For the PFWs, which were predominantly contaminated with organic chemicals, A. sinjiensis was the most sensitive species (EC50 value 2-17 times lower than for any other test species). For the predominantly metal-contaminated mine tailing liquors, its sensitivity was similar to that of other test species used. The modified 48-h acute

  2. Toxicity of ZnO nanoparticles to the copepod Acartia tonsa, exposed through a phytoplankton diet.

    PubMed

    Jarvis, Tayler A; Miller, Robert J; Lenihan, Hunter S; Bielmyer, Gretchen K

    2013-06-01

    Zinc oxide (ZnO) nanoparticles are being increasingly utilized in a variety of products and applications and are therefore commonly discharged into aquatic environments, increasing exposure and potentially impacting aquatic organisms. Zinc oxide nanoparticles can depress growth of some marine phytoplankton, and several examples of nanoparticle trophic transfer have been documented, although not within planktonic communities. The authors test whether feeding on ZnO-exposed phytoplankton could cause toxic effects in a widespread and ecologically important marine grazer, the copepod Acartia tonsa. The authors exposed the diatom Thalassiosira weissflogii to ZnO nanoparticles for 7 d and measured growth, zinc accumulation, and zinc distribution within the algal cells to elucidate bioavailability to grazing copepods. Thalassiosira weissflogii cultured with nano-ZnO were continuously fed to A. tonsa for 7 d, and reproduction and survival were quantified. A dose-dependent growth reduction was observed in T. weissflogii exposed to nano-ZnO, with a 20% effective concentration (EC20) of 70 µg/L Zn and a lowest observed effect concentration (LOEC) of 99 µg/L Zn. Zinc accumulation in the algae occurred dose-dependently over time, with the majority of the zinc partitioning into the cell wall fraction. Feeding on ZnO-exposed diatoms led to a decrease in copepod survival and reproduction. The EC20s corresponding to the dissolved zinc concentration in the T. weissflogii exposure media were 112 µg/L (13 µg/g dry wt) and 143 µg/L (16 µg/g dry wt), and the LOECs were 168 µg/L (17 µg/g dry wt) and 263 µg/L (21 µg/g dry wt) for copepod survival and reproduction, respectively. These results provide evidence of trophic transfer of metal contaminants associated with metal oxide nanomaterials within a marine plankton community, leading to a reduction in individual demographic performance of an important coastal marine grazer. PMID:23417698

  3. 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.

  4. Evolutionary mechanisms of habitat invasions, using the copepod Eurytemora affinis as a model system.

    PubMed

    Lee, Carol Eunmi

    2016-01-01

    The study of the copepod Eurytemora affinis has provided unprecedented insights into mechanisms of invasive success. In this invited review, I summarize a subset of work from my laboratory to highlight key insights gained from studying E. affinis as a model system. Invasive species with brackish origins are overrepresented in freshwater habitats. The copepod E. affinis is an example of such a brackish invader, and has invaded freshwater habitats multiple times independently in recent years. These invasions were accompanied by the evolution of physiological tolerance and plasticity, increased body fluid regulation, and evolutionary shifts in ion transporter (V-type H(+) ATPase, Na(+), K(+)-ATPase) activity and expression. These evolutionary changes occurred in parallel across independent invasions in nature and in laboratory selection experiments. Selection appears to act on standing genetic variation during invasions, and maintenance of this variation is likely facilitated through 'beneficial reversal of dominance' in salinity tolerance across habitats. Expression of critical ion transporters is localized in newly discovered Crusalis leg organs. Increased freshwater tolerance is accompanied by costs to development time and greater requirements for food. High-food concentration increases low-salinity tolerance, allowing saline populations to invade freshwater habitats. Mechanisms observed here likely have relevance for other taxa undergoing fundamental niche expansions. PMID:27087851

  5. 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.

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

    PubMed

    Nepstad, Raymond; Størdal, Ingvild Fladvad; Brönner, Ute; Nordtug, Trond; Hansen, Bjørn 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

  7. Copepod behavior in thin layers of attractive and deterrent chemical cues

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  8. 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

  9. 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

  10. The hydrodynamics of two species of copepods: temperate and subtropical Euchaeta

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; Catton, K. B.; Yen, J.

    2009-11-01

    Different species of the copepod genera Euchaeta live in polar, temperate, and subtropical ocean environments. Euchaeta elongata is a species found in temperate waters and is roughly double the size of the subtropical species Euchaeta rimana. The kinematic viscosity of the ocean water in the temperate latitude (8 deg C) is roughly 50% greater than that of subtropical environments (23 deg C). We hypothesize that these species have adapted to the local fluid environment to create flow disturbances that facilitates optimal prey capture and predator avoidance. Particle Image Velocimetry (PIV) was used to quantify the flow surrounding each copepod species during cruising and escaping behaviors. Seven to nine replicates for each species were collected for free swimming specimens during both cruise and escape behavior. The average Reynolds number of both species was found to be on the order of 10 for cruising behavior and 1000 for escapes. During cruising, the spatial extent of the region of flow disturbance, defined by a threshold of the maximum principle rate of deformation, was not significantly different between species. In contrast, the spatial extent of the region of flow disturbance during escapes was larger for E. elongata. Further, the viscous dissipation rate was similar for the species during cruising, whereas E. elongata had a significantly greater viscous dissipation rate during escape behavior.

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

    NASA Astrophysics Data System (ADS)

    Calbet, Albert; Carlotti, François; 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 μm 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. 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

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

    NASA Astrophysics Data System (ADS)

    Kiko, Rainer; Hauss, Helena; Buchholz, Friedrich; Melzner, Frank

    2016-04-01

    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 could fuel bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean considerably. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a down-regulation of ammonium excretion. We exposed calanoid copepods from the Eastern Tropical North Atlantic (ETNA; Undinula vulgaris and Pleuromamma abdominalis) and euphausiids from the Eastern Tropical South Pacific (ETSP; Euphausia mucronata) and the ETNA (Euphausia gibboides) to different temperatures, carbon dioxide and oxygen levels to study their survival, respiration and excretion rates at these conditions. An increase in temperature by 10 °C led to an approximately 2-fold increase of the respiration and excretion rates of U. vulgaris (Q10, respiration = 1.4; Q10, NH4-excretion = 1.6), P. abdominalis (Q10, respiration = 2.0; Q10, NH4-excretion = 2.4) and

  14. Feeding response in marine copepods as a measure of acute toxicity of four anti-sea lice pesticides.

    PubMed

    Van Geest, Jordana L; Burridge, Les E; Fife, Frederick J; Kidd, Karen A

    2014-10-01

    Anti-sea lice pesticides used in salmon aquaculture are released directly into the environment where non-target organisms, including zooplankton, may be exposed. The toxicity of four pesticides to field-collected copepods was examined in 1-h exposures with lethality and feeding endpoints determined 5-h post-exposure using staining techniques. Copepods were immobilized within 1 h, at aquaculture treatment concentrations of deltamethrin (AlphaMax), cypermethrin (Excis), and hydrogen peroxide (InteroxParamove50). All organisms showed vital staining, indicating immobilized organisms were still alive, thus LC50s were not determined. Feeding on carmine particles was inhibited and EC50s ranged from 0.017 to 0.067 μg deltamethrin/L, 0.098-0.36 μg cypermethrin/L, and 2.6-10 mg hydrogen peroxide/L, representing 30- to 117-fold, 13- to 51-fold, and 120- to 460-fold dilutions of the respective aquaculture treatments. No effects were observed in copepods exposed to azamethiphos (Salmosan) at 5-times the aquaculture treatment. Acute exposure to three of the four pesticides affected feeding and mobility of copepods at environmentally-realistic concentrations. PMID:25440784

  15. Temperature impact on the trophic transfer of fatty acids in the congeneric copepods Acartia tonsa and Acartia clausi

    NASA Astrophysics Data System (ADS)

    Werbrouck, Eva; Tiselius, Peter; Van Gansbeke, Dirk; Cervin, Gunnar; Vanreusel, Ann; De Troch, Marleen

    2016-06-01

    Copepods of the genus Acartia occur worldwide and constitute an important link to higher trophic levels in estuaries. However, biogeographical shifts in copepod assemblages and colonization of certain European estuaries by the invader A. tonsa, both driven or enhanced by increasing ocean temperature, raise the pressure on autochthonous copepod communities. Despite the profound effect of temperature on all levels of biological organization, its impact on the fatty acid (FA) dynamics of Acartia species is understudied. As certain FAs exert a bottom-up control on the trophic structure of aquatic ecosystems, temperature-induced changes in FA dynamics of Acartia species may impact higher trophic levels. Therefore, this study documents the short-term temperature responses of A. tonsa and A. clausi, characterized by their warm- versus cold-water preference respectively, by analyzing the FA profiles of their membrane and storage lipids under 5 and 15 °C. Copepods that were fed an ad libitum diet of the diatom Thalassiosira weissflogii (bloom conditions) under 15 °C increased their storage FA content substantially. Furthermore, the membrane FA composition of A. tonsa showed a more profound temperature response compared with A. clausi which might be linked with the eurythermal character of the former.

  16. Copepods attain high abundance, biomass and production in the absence of large predators but suffer cannibalistic loss

    NASA Astrophysics Data System (ADS)

    Uye, Shin-ichi; Liang, Dong

    1998-06-01

    Zooplankton samples were collected at intervals of 3-5 days for a year in Fukuyama Harbor, a eutrophic inlet of the Inland Sea of Japan, using a 62-μm-mesh plankton net. The copepod community, which consisted of twelve species, had a very high abundance, biomass and production rate. Acartia omorii, Centropages abdominalis, Oithona davisae and Paracalanus sp. were the most abundant species. The annual average abundance and biomass of adults and copepodites were 1.10×10 5 ind. m -3 and 39.1 mg C m -3, respectively, one of the highest values so far reported in coastal marine waters. The annual average production rate was 6.85 mg C m -3 d -1, of which Paracalanus sp., O. davisae, A. omorii and C. abdominalis accounted for 27, 26, 25 and 13%, respectively. The combination of an abundant food supply and scarce large predators, except for the ctenophore Bolinopsis mikado which was abundant only in mid-summer, allowed the high abundance, biomass and production of copepods. However, predation on copepod eggs and early nauplii by adults and late copepodites reduced the population recruitment rate and copepod production.

  17. 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

  18. 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.

  19. Influence of UVB radiation on the lethal and sublethal toxicity of dispersed crude oil to planktonic copepod nauplii.

    PubMed

    Almeda, Rodrigo; Harvey, Tracy E; Connelly, Tara L; Baca, Sarah; Buskey, Edward J

    2016-06-01

    Toxic effects of petroleum to marine zooplankton have been generally investigated using dissolved petroleum hydrocarbons and in the absence of sunlight. In this study, we determined the influence of natural ultraviolet B (UVB) radiation on the lethal and sublethal toxicity of dispersed crude oil to naupliar stages of the planktonic copepods Acartia tonsa, Temora turbinata and Pseudodiaptomus pelagicus. Low concentrations of dispersed crude oil (1 μL L(-1)) caused a significant reduction in survival, growth and swimming activity of copepod nauplii after 48 h of exposure. UVB radiation increased toxicity of dispersed crude oil by 1.3-3.8 times, depending on the experiment and measured variables. Ingestion of crude oil droplets may increase photoenhanced toxicity of crude oil to copepod nauplii by enhancing photosensitization. Photoenhanced sublethal toxicity was significantly higher when T. turbinata nauplii were exposed to dispersant-treated oil than crude oil alone, suggesting that chemical dispersion of crude oil may promote photoenhanced toxicity to marine zooplankton. Our results demonstrate that acute exposure to concentrations of dispersed crude oil and dispersant (Corexit 9500) commonly found in the sea after oil spills are highly toxic to copepod nauplii and that natural levels of UVB radiation substantially increase the toxicity of crude oil to these planktonic organisms. Overall, this study emphasizes the importance of considering sunlight in petroleum toxicological studies and models to better estimate the impact of crude oil spills on marine zooplankton. PMID:27003367

  20. 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

  1. Reproductive and developmental effects of atrazine on the estuarine meiobenthic copepod Amphiascus tenuiremis.

    PubMed

    Bejarano, Adriana C; Chandler, G Thomas

    2003-12-01

    Atrazine is one of the most widely used herbicides in the United States. Atrazine concentrations in coastal environments chronically range from 90 ng/L to 46 microg/L, with rare but measured concentrations near 60 microg/L at edge-of-field conditions. Chronic atrazine effects on estuarine benthos exposed to environmentally relevant concentrations are unknown. The purpose of this research was to assess atrazine reproductive and developmental effects over multiple-generation exposures of the copepod Amphiascus tenuiremis. Copepods were chronically exposed to two environmentally relevant nominal atrazine concentrations (2.5 and 25 microg/L, and to an environmentally unrealistic concentration (250 microg/L). Chronic exposures were performed using a 96-well microplate life cycle bioassay. Individual stage I copepodites (C1, n = 60/treatment) were reared through two generations (F0 and F1) to sexual maturity and individually mated in microwells containing 200 microl of atrazine solution. Copepod survival across all treatments and generations was >95%. Atrazine did not affect development to reproductive maturity, time to egg extrusion, or time to egg hatch (p > 0.05). However, reproductive failures increased across generations with increasing atrazine concentrations. Reproductive failures in the 0-, 2.5-, 25-, and 250-microg/L atrazine treatments were 11, 11, 20, and 24% for the F0 and 4, 9, 26, and 38% for the F1, respectively. Compared to controls, total nauplii production per female was reduced by approximately 22% in F0 females exposed to 250 microg/L atrazine (p < 0.05), and by approximately 23%, approximately 27%, and approximately 32% in F1 females exposed to 2.5-, 25-, and 250-microg/L atrazine treatments, respectively (p < 0.05). The combined effect of reproductive failure and reduced offspring production significantly reduced total population growth in the F1 generation (p < 0.05) even at atrazine concentrations lower than that considered safe for seawater

  2. 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.

  3. 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.

  4. Life cycle of Schizochytriodinium calani nov. gen. nov. spec., a dinoflagellate parasitizing copepod eggs

    NASA Astrophysics Data System (ADS)

    Elbrächter, Malte

    1988-09-01

    During the Polarstern-cruise ARK IV/2 June 1987, in the Fram Strait, dinophytes parasitizing copepod eggs were observed. In the laboratory on board, vegetative reproduction was documented and re-infection of Calanus glacialis and C. hyperboreus eggs was experimentally established. During food uptake, a primary cyst produces successively several secondary cysts, all separating immediately after formation from the primary cyst. In every one of these free floating secondary cysts up to 256 dinospores are formed by palintomy. Re-infection only occurred after a “maturation time” of at least 2 days after formation of the dinospores. The life cycle is compared to that of other similar parasitic dinophyte genera: Apodinium Chatton, Chytriodinium Chatton, Dissodinium Klebs in Pascher and Myxodinium Cachon, Cachon & Bouquaheux. As the taxon under discussion does not fit in with any species or genus known so far, it is described as Schizochytriodinium calani nov. gen. nov. spec.

  5. 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.

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

    PubMed

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

    2012-02-01

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

  7. 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

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

    PubMed Central

    Sereda, Sergej Vital’evič; Wilke, Thomas; Schultheiß, 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

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

    PubMed Central

    2011-01-01

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

  10. 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

  11. 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

  12. Egg size and reproductive adaptations among Arctic deep-sea copepods (Calanoida, Paraeuchaeta)

    NASA Astrophysics Data System (ADS)

    Auel, Holger

    2004-10-01

    Reproductive strategies of the four congeneric and sympatric calanoid copepods Paraeuchaeta glacialis, P. norvegica, P. barbata, and P. polaris were studied in the Arctic Greenland Sea. Females of all species produce egg sacs and carry their brood attached to the genital opening until the offspring hatch. However, egg size and lipid content as well as clutch size and the fraction of females carrying egg masses show characteristic differences among the four species. P. glacialis and P. norvegica produce large numbers (37 to more than 50) of relatively small eggs, whereas P. barbata and P. polaris rely on small numbers (10 to 19 and 4 to 6, respectively) of large eggs with a high energy content. There is no correlation between female body size and egg size or clutch size, respectively. Females of the smallest species, P. polaris, produce relatively large eggs and show the highest energetic investment per egg. In contrast, energetic investment per clutch is highest in P. glacialis. Reproductive adaptations appear to be strongly related to the depth range inhabited by the respective species. In the central Greenland Sea P. glacialis and P. norvegica occur in the epipelagial and upper mesopelagial, whereas the other two species inhabit lower mesopelagic to bathypelagic depths. Thus, egg size increases with depth of occurrence, whereas clutch size is inversely correlated with depth. This observation leads to the hypothesis that the evolution of large eggs in deep-sea copepods may enable hatchlings to rely on a lecithotrophic development and thus represents a successful adaptation to cope with the limited food supply at great depths, whereas high offspring numbers in epipelagic species compensate for higher predation risks in the euphotic zone.

  13. Following the invisible trail: kinematic analysis of mate-tracking in the copepod Temora longicornis.

    PubMed Central

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

    1998-01-01

    We have analysed the fine-scale kinematics of movement of male and female copepods, Temora longicornis, to resolve how these small animals find their mates. Location of the trail initially involves rapid random turning and high rates of directional change. Males subsequently increase their rate of movement as they follow the trail, and execute a regular pattern of counter turns in both x,z and y,z planes to stay near or within the central axis of the odour field. Pursuit behaviour of males is strongly associated with female swimming behaviour, suggesting that quantifiable variations in the structure of the odour signal released by females affects male tracking. The behavioural components of mate tracking in Temora are very similar to those of other animals that employ chemically mediated orientation in their search for mates and food, and we conclude that male Temora find their mates using chemoperception. The kinematic analysis indicates both sequential and simultaneous taxis mechanisms are used by Temora to follow the odour signal. This, in turn, indicates that rather than responding to a diffuse plume, males are following a signal more accurately characterized as a chemical trail, and copepods appear to use mechanisms that are similar to those employed by trail-following terrestrial insects such as ants. While Temora expresses similar behaviours to those of a variety of chemosensory organisms, the ability to track a three-dimensional odour trail appears unique, and possibly depends on the persistence of fluid-borne odour signals created in low Reynolds number hydrodynamic regimes. PMID:9652125

  14. 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.

  15. Plankton distribution and the impact of copepod grazing on primary production in Fram Strait, Greenland Sea

    NASA Astrophysics Data System (ADS)

    Hirche, H.-J.; Baumann, M. E. M.; Kattner, G.; Gradinger, R.

    1991-08-01

    Two hydrobiological transects across the East Greenland Shelf and the open waters of Fram Strait in summer were chosen to illustrate the distribution and production of phyto- and zooplankton in relation to water masses and ice cover. The parameters used were temperature and salinity, inorganic nutrients, chlorophyll a, primary production, phytoplankton species composition, abundance of the dominant herbivorous copepods Calanus finmarchicus, C. glacialis, C. hyperboreus, Metridia longa and egg production of C. finmarchicus and C. glacialis. Grazing impact of copepodites and adults of these four species was modelled for each station by using egg production rates as an index of growth. Seasonal development of plankton communities was closely associated with the extent of the ice cover, hydrographic conditions and the water masses typical of the different hydrographic domains. Four regions were identified from their biological activities and physical environment: The Northeast Water polynya on the East Greenland Shelf, with a springbloom of diatoms and active reproduction of herbivorous copepods. The pack ice region, dominated by small flagellates and negligible grazing activities. The marginal ice zone, with high variability and strong gradients of autotroph production related to eddies and ice tongues, an active microbial loop and low egg production. The open water, with high station-to-station variability of most of the parameters, probably related to hydrographic mesoscale activities. Here, Phaeocystis pouchetii was a prominent species in the phytoplankton communities. Its presence may at least partly be responsible for the generally low egg production in the open waters. Grazing impact on primary production was always small, due to low zooplankton biomass in the polynya and due to low ingestion in the remaining regions.

  16. 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...

  17. 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.

  18. 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

  19. Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants.

    PubMed

    Michalec, François-Gaël; Holzner, Markus; Menu, Dominique; Hwang, Jiang-Shiou; Souissi, Sami

    2013-08-15

    Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L⁻¹, cadmium at 45 n gL⁻¹ and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L⁻¹ all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The increase in speed and activity resembles an escape reaction permitting copepods to evade stressful conditions. Overall, these results indicate that environment-relevant concentrations of pollutants can induce rapid changes in copepod behavior. Since behavioral processes represent a fundamental element in the ecology of copepods, our results raise concern about the effects of background levels of pollution on a

  20. Effect of the copepod parasite Nicothoë 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 Nicothoë 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

  1. 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.

  2. 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

  3. Ecotoxicity of triphenyltin on the marine copepod Tigriopus japonicus at various biological organisations: from molecular to population-level effects.

    PubMed

    Yi, Andy Xianliang; Han, Jeonghoon; Lee, Jae-Seong; Leung, Kenneth M Y

    2014-09-01

    Triphenyltin compounds (TPTs), as effective biocides for different industrial and agricultural purposes, have been detected in coastal marine environments worldwide, in particular in Asian countries. However, little is known about their toxicity to marine organisms. This study comprehensively investigated the molecular, individual and population responses of the marine copepod, Tigriopus japonicus upon waterborne exposure to TPT chloride (TPTCl). Our results indicated that TPTCl was highly toxic to adult T. japonicus, with a 96-h LC50 concentration at 6.3 μg/L. As shown in a chronic full life-cycle test, T. japonicus exposed to 1.0 μg/L TPTCl exhibited a delay in development and a significant reduction of population growth, in terms of the intrinsic rate of increase (r m ). Based on the negative relationship between the r m and exposure concentration, a critical effect concentration was estimated at 1.6 μg/L TPTCl; at or above which population extinction could occur. At 0.1 μg/L TPTCl or above, the sex ratio of the second generation of the copepod was significantly altered and changed to a male-biased population. At molecular level, the inhibition of the transcriptional expression of glutathione S-transferase related genes might lead to dysfunction of detoxification, and the inhibition of retinoid X receptor mRNA expression implied an interruption of the growth and moulting process in T. japonicus. As the only gene that observed up-regulated in this study, the expression of heat shock protein 70 (hsp70) increased in a concentration-dependent manner, indicating its function in protecting the copepod from TPT-mediated oxidative stress. The study advances our understanding on the ecotoxicity of TPT, and provides some initial data on its toxic mechanisms in small crustaceans like copepods. PMID:24981692

  4. 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

  5. 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.

  6. Acute toxicity of dispersed crude oil on the cold-water copepod Calanus finmarchicus: Elusive implications of lipid content.

    PubMed

    Hansen, Bjørn Henrik; Jager, Tjalling; Altin, Dag; Øverjordet, Ida B; Olsen, Anders J; Salaberria, Iurgi; Nordtug, Trond

    2016-01-01

    In this investigation, acute toxicity data were used from two previously reported studies where cold-water copepods were exposed to mechanically dispersed (MD) and chemically (CD) dispersed oil. In one of these studies, concentration-dependent mortality was observed, whereas no apparent relationship between exposure concentration and mortality was found in the other. The only marked difference between the studies is that copepods in the first experiment displayed a lower lipid sac volume (on average) than in the second one. In this study additional biometric data on lipid content were utilized and observed effects and toxicokinetics modeling applied in order to investigate whether differences in sensitivity between copepod cohorts might be explained by differences in lipid content. Results suggest that although a considerable lipid sac might retard toxicokinetics, the observed differences in lipid volume are not sufficient to explain differences in toxicity. Further, there are no apparent indications that acute toxic stress leads to lipid depletion, or that acute increased mortality rate selectively affects lipid-poor individuals. It is conceivable that other potential explanations exist, but the causal relationship between lipid content and increased mortality frequency remains elusive. PMID:27484137

  7. 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

  8. The toxicity of the three antifouling biocides DCOIT, TPBP and medetomidine to the marine pelagic copepod Acartia tonsa.

    PubMed

    Wendt, Ida; Backhaus, Thomas; Blanck, Hans; Arrhenius, Åsa

    2016-07-01

    Copepods, the largest group of pelagic grazers, are at risk from exposure to antifouling biocides. This study investigated the toxicity of the antifouling biocides 4,5-dichloro-2-octyl-1,2-thiazol-3(2H)-one (DCOIT), triphenylborane pyridine (TPBP) and 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (medetomidine) to the copepod Acartia tonsa, using mortality and egg production as endpoints. The toxicity ranking for mortality was as follows: DCOIT (LC50 57 nmol l(-1)) = TPBP (LC50 56 nmol l(-1)) > medetomidine (LC50 241 nmol l(-1)). Egg production was more sensitive than mortality to TPBP (EC50 3.2 nmol l(-1)), while DCOIT and medetomidine inhibited egg production at roughly the same concentrations (72 and 186 nmol l(-1) respectively). Furthermore, TPBP seems to affect egg hatching directly which was not the case for DCOIT and medetomidine. DCOIT and medetomidine might pose an environmental risk as they have been reported to occur in different exposure scenarios or analytical surveys at concentrations only 2-3 times lower than the respective EC10. Reported environmental concentrations of TPBP are few but clearly lower than the EC10 values reported here, suggesting current risk of TPBP to copepods to be moderate. PMID:26984312

  9. 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

  10. 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