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1

Trophic role of small cyclopoid copepod nauplii in the microbial food web: a case study in the coastal upwelling system off central Chile  

Microsoft Academic Search

Copepod grazing impact on planktonic communities has commonly been underestimated due to the lack of information on naupliar\\u000a feeding behaviour and ingestion rates. That is particularly true for small cyclopoid copepods, whose nauplii are mainly in\\u000a the microzooplankton size range (Oithona spp. nauplii was investigated off Concepción (central Chile, ~36°S) during the highly productive upwelling season, when maximum\\u000a abundances of

Daniela BottjerCarmen; Carmen E. Morales; Ulrich Bathmann

2010-01-01

2

Cyclopoid copepods associated with antipatharian coelenterates in Madagascar  

Microsoft Academic Search

Previous work (in i960) at Nosy Bé, in northwestern Madagascar, resulted in the collection by dredging of the antipatharian Stichopathes echinulata Brook parasitized by the copepod Vahinius petax Humes, 1967. More recently (in 1964 and 1967) I have obtained by SCUBA diving several other antipatharians with which the copepods described below were associated. The collection in 1964 was made as

A. G. Humes

1969-01-01

3

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)

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).

Kim, Il-Hoi; Moon, Seong Yong

2013-12-01

4

Feeding strategies of planktonic cyclopoids in lacustrine ecosystems  

NASA Astrophysics Data System (ADS)

Present knowledge of feeding tactics and behaviour, food composition and consumption, and feeding strategies of planktonic cyclopoid copepods is synthesized. Planktonic freshwater cyclopoids consume both plant and animal food. Predatory feeding is highly selective: prey species differ in their size, defense structures, the distance at which they are recognized by the cyclopoid, defensive behaviour when attacked, and their occurrence in the same space as the predator. Within a prey species, cyclopoids select for smaller individuals. The impact of cyclopoid predation on the other zooplankton may be an important source of mortality. However, algal material is consumed to a large extent by the adult and later developmental stages and is a necessary food source for the youngest stages, which have to compete with other planktonic herbivores. Some implications of these food requirements for life strategies of planktonic cyclopoid species in the seasonally changing environments are discussed.

Brandl, Zden?k

1998-06-01

5

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

PubMed

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

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

2014-02-01

6

DAMAGE TO FISH FRY BY CYCLOPOID COPEPODS  

Microsoft Academic Search

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

CHARLES C. DAVIS

7

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

NASA Astrophysics Data System (ADS)

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 occasionally. Copepodid stages and adults use non-moving and often extended setae on the tips of their A1 to perceive predators at a distance. This structure and their pronounced escape motion may reduce their vulnerability to predation as compared to nauplii.

Paffenhöfer, G.-A.

1998-06-01

8

The effect of temperature, and food quantity and quality on the growth and development rates in laboratory-cultured copepods and cladocerans from a Sri Lankan reservoir  

Microsoft Academic Search

Length growth, instar durations, fecundity and mortality rates of five species of microcrustacean zooplankton from a tropical reservoir were measured in relation to food quantity and temperature in laboratory cultures. Three cladocerans (Ceriodaphnia cornuta, Moina micrura, Diaphanosoma excisum), one calanoid copepod (Heliodiaptomus viduus), and one cyclopoid copepod (Mesocyclops thermocyclopoides) were studied. Filtered seston (45 mu m mesh) from a local

P. Bandu Amarasinghe; M. Boersma; J. Vijverberg

1997-01-01

9

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

PubMed Central

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

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

2013-01-01

10

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

USGS Publications Warehouse

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.

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

2000-01-01

11

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

12

Copepod Web Portal  

NSDL National Science Digital Library

The Copepod Web Portal, from the Department of Environmental Sciences at the University of L'Aquila in Italy, provides a comprehensive and nicely designed set of online resources for those interested in this "largest and most diversified group of crustaceans." The site includes a detailed review of copepod systematics; an international directory of copepodologists; a sizeable list of references; and numerous links to related books, journals, papers, and other resources -- including downloadable version of Monoculus: The Copepod Newsletter. A small number of links lead to sites not accessible without special permission.

Pesce, G. L.

1999-01-01

13

Parasitic copepods on immigrant and native clupeid fishes caught in Egyptian coastal waters off Alexandria.  

PubMed

Three species of parasitic copepods, one each from the siphonostomatoid families Lernanthropidae and Lernaeopodidae and one from the cyclopoid family Bomolochidae, are redescribed based on material collected from the gills of four fish species belonging to the family Clupeidae caught from coastal waters off Alexandria, Egypt. The recorded parasites are: Mitrapus oblongus (Pillai, 1964), found on Etrumeus teres (Dekay), an immigrant species from the Red Sea, and on Sardinella aurita Valenciennes, a native Mediterranean species; Clavellisa ilishae Pillai, 1962 found only on S. aurita; and Nothobomolochus fradei Marques, 1965 found on Herklotsichthys punctatus (Rüppell), an immigrant species from the Red Sea, and on Sardina pilchardus (Walbaum), a native Mediterranean species. The first two of these copepods have been reported before on clupeid hosts from the Indian Ocean. The third was known from the eastern South Atlantic and the Arabian Gulf. None of the copepods has previously been recorded in the Mediterranean. All of the parasites reported here constitute new records for these hosts. Two of the hosts are Erythrean (=Lessepsian) immigrants and were caught in Mediterranean waters off the Egyptian coast. The original description of N. fradei (Marques, 1965) is inadequate by modern standards. This species is fully described here for the first time. The male of M. oblongus was briefly described by Pillai (1964), but its mouthparts are described in detail here for the first time. PMID:20401576

El-Rashidy, Hoda; Boxshall, Geoff A

2010-05-01

14

Impacts of an uncontrolled phosphogypsum dumpsite on summer distribution of phytoplankton, copepods and ciliates in relation to abiotic variables along the near-shore of the southwestern Mediterranean coast.  

PubMed

In connection with the Taparura Project, studies of spatial distribution of the crustacean zooplankton community, nutrients, phytoplankton and ciliates were conducted in July 2007 at 45 stations spread over fifteen transects along the coast north of Sfax. The results showed that the N/P ratio was lower than the Redfield ratio, suggesting potential N limitation. Phytoplankton was characterised by the proliferation of several diatoms, while ciliates were largely dominated by spirotrichs. Copepods were the most abundant zooplankton present during the entire study period, comprising 61% of the total zooplankton community. Twelve copepod families were identified at every station, with a high percentage of Oithonidae (77% of copepods) dominated by Oithona nana. The abundance of this species was correlated with that of diatoms, Cocoolithophorideae and ciliated Colpodea, suggesting that O. nana may feed on a wide range of prey. Despite human pressure and industrial activities, the coastal waters north of Sfax showed a wide diversity of phytoplankton, ciliates and zooplankton. PMID:22154276

Rekik, Amira; Drira, Zaher; Guermazi, Wassim; Elloumi, Jannet; Maalej, Sami; Aleya, Lotfi; Ayadi, Habib

2012-02-01

15

The Kinematics of Swimming and Relocation Jumps in Copepod Nauplii  

PubMed Central

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

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

2012-01-01

16

The kinematics of swimming and relocation jumps in copepod nauplii.  

PubMed

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

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

2012-01-01

17

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

NASA Astrophysics Data System (ADS)

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

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

1998-06-01

18

Senescence and Sexual Selection in a Pelagic Copepod  

PubMed Central

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

Ceballos, Sara; Kiørboe, Thomas

2011-01-01

19

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

USGS Publications Warehouse

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

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

2001-01-01

20

Evolution of bioluminescence in marine planktonic copepods.  

PubMed

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

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

2012-06-01

21

Molecular Systematic of Three Species of Oithona (Copepoda, Cyclopoida) from the Atlantic Ocean: Comparative Analysis Using 28S rDNA  

PubMed Central

Species of Oithona (Copepoda, Cyclopoida) are highly abundant, ecologically important, and widely distributed throughout the world oceans. Although there are valid and detailed descriptions of the species, routine species identifications remain challenging due to their small size, subtle morphological diagnostic traits, and the description of geographic forms or varieties. This study examined three species of Oithona (O. similis, O. atlantica and O. nana) occurring in the Argentine sector of the South Atlantic Ocean based on DNA sequence variation of a 575 base-pair region of 28S rDNA, with comparative analysis of these species from other North and South Atlantic regions. DNA sequence variation clearly resolved and discriminated the species, and revealed low levels of intraspecific variation among North and South Atlantic populations of each species. The 28S rDNA region was thus shown to provide an accurate and reliable means of identifying the species throughout the sampled domain. Analysis of 28S rDNA variation for additional species collected throughout the global ocean will be useful to accurately characterize biogeographical distributions of the species and to examine phylogenetic relationships among them. PMID:22558245

Cepeda, Georgina D.; Blanco-Bercial, Leocadio; Bucklin, Ann; Berón, Corina M.; Viñas, María D.

2012-01-01

22

Algal Toxins Alter Copepod Feeding Behavior  

PubMed Central

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

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

2012-01-01

23

Observing copepods through a genomic lens  

PubMed Central

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

2011-01-01

24

The microbiome of North Sea copepods  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

25

Algal Toxins Alter Copepod Feeding Behavior  

Microsoft Academic Search

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

Jiarong Hong; Siddharth Talapatra; Joseph Katz; Patricia A. Tester; Rebecca J. Waggett

2012-01-01

26

Components of mating behavior in planktonic copepods  

Microsoft Academic Search

Successful mating behavior is essential to the survival of all sexually reproducing organisms. To explore the components of a successful mating interaction for planktonic copepods, mating behavior can be compared to predatory behavior using the “components of predation” framework of C.S. Holling. As the components of predation can be considered to include encounter, attack, capture and ingestion, analogously, mating behavior

Edward J Buskey

1998-01-01

27

Algal toxins alter copepod feeding behavior.  

PubMed

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

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

2012-01-01

28

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

NASA Astrophysics Data System (ADS)

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

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

29

Occurrence of heavy copepod infestation on Hemiramphus lutkei and double parasitisms on Hemiramphus far with copepod (Lernaeenicus hemiramphi) and isopod (Mothocya plagulophora).  

PubMed

In the present study about, 66 copepod parasites of Lernaeenicus hemiramphi of two Hemiramphus sp., H. far (17 copepod) and H. lutkei (49 copepod), and an isopod (Mothocya plagulophora) on the gill chamber were observed. H. lutkei was added as a new host for L. hemiramphi. The copepod infestation was almost on the ventral side of the hosts. PMID:25035596

Vijayakumar, R; Raja, K; Velvizhi, S; Sinduja, K; Gopalakrishnan, A

2014-09-01

30

Mobiline peritrich riders on Australian calanoid copepods  

Microsoft Academic Search

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

John D. Green; Russell J. Shiel

2000-01-01

31

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

PubMed Central

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

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

2013-01-01

32

Copepod hatching success in marine ecosystems with high diatom concentrations  

Microsoft Academic Search

Diatoms dominate spring bloom phytoplankton assemblages in temperate waters and coastal upwelling regions of the global ocean. Copepods usually dominate the zooplankton in these regions and are the prey of many larval fish species. Recent laboratory studies suggest that diatoms may have a deleterious effect on the success of copepod egg hatching. These findings challenge the classical view of marine

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

2002-01-01

33

Sexual dimorphism in calanoid copepods: morphology and function  

Microsoft Academic Search

Mate location and recognition are essentially asymmetrical processes in the reproductive biology of calanoid copepods with the active partner (the male) locating and catching the largely passive partner (the female). This behavioural asymmetry has led to the evolution of sexual dimorphism in copepods, playing many pivotal roles during the various successive phases of copulatory and post-copulatory behaviour. Sexually dimorphic appendages

Susumu Ohtsuka; Rony Huys

2001-01-01

34

Relative sensitivity of hyporheic copepods to chemicals.  

PubMed

The sensitivity of harpacticoid copepods was tested against selected pollutants. Acute toxicity tests were carried out for five hyporheic species exposed to pesticides, ammonia, and metals. The stygoxene Bryocamptus zschokkei, B. minutus, B. pygmaeus and Attheyella crassa; and the stygophilous B. echinatus were sampled and cultured during 8 months in controlled conditions. A first test protocol is presented. The acute endpoints among species fell within one order of magnitude. The sensitivity among various species evaluated in this study is consistent and the choice of species for further sediment/groundwater assessment is not specific to a chemical class. These potential test organisms would be more suitable to protect meiofaunal communities. PMID:19005609

Di Marzio, W D; Castaldo, D; Pantani, C; Di Cioccio, A; Di Lorenzo, T; Sáenz, M E; Galassi, D M P

2009-04-01

35

Copepod diffusion within multifractal phytoplankton fields  

NASA Astrophysics Data System (ADS)

Oceanic turbulence has been considered for a while as one of the main sources of the heterogeneity of the phytoplankton field over a wide range of scales. However, it is only recently that the intermittency of turbulence has been taken into account, although it is rather indispensable in the explanation of the observed patchiness of the plankton field. In order to improve the understanding and characterization of the diffusion of copepods within an heterogeneous phytoplankton field, we developed a model based on particle diffusion in a multifractal field. After discussing this model with some detail, we used it and the corresponding numerical simulations in order to investigate the fundamental question: does the strong heterogeneity of the phytoplankton generate a anomalous diffusion of the copepods? Although a positive answer is obtained in a rather straightforward manner for a one-dimensional multifractal field of phytoplankton concentration, the answer is rather more involved for a greater (topological) dimension of the field, contrary to some previous claims.

Marguerit, C.; Schertzer, D.; Schmitt, F.; Lovejoy, S.

1998-09-01

36

Molecular and microscopic evidence of viruses in marine copepods.  

PubMed

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

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

2013-01-22

37

Molecular and microscopic evidence of viruses in marine copepods  

PubMed Central

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

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

2013-01-01

38

LABORATORY STUDIES OF PREDATION BY MARINE COPEPODS ON FISH LARVAE  

E-print Network

. Caloric requirements were calculated from oxygen consumption measurements and showed that only 1 to 4 anchovy larvae are required per day per copepod to satisfy the metabolic needs of Labidocera, depending

39

Circular Polarization of Transmitted Light by Sapphirinidae Copepods  

E-print Network

, in other animals it was suggested to take part in mate choice, species recognition, and other forms of communication. Highlights: Planktonic Sapphirinidae copepods were found to circularly polarize the light passing

Rosen, Joseph

40

Physical controls on copepod aggregations in the Gulf of Maine  

E-print Network

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

Woods, Nicholas W

2013-01-01

41

Imidazolopyrazine bioluminescence in copepods and other marine organisms  

Microsoft Academic Search

The aim of this work was to establish the role of imidazolopyrazines in the bioluminescence of copepods and other marine organisms. A highly sensitive assay (down to 10-17 mol) for coelenterazine was established using reactivation of the Ca2+-activated photoprotein obelin, and for vargulin usingVargula hilgendorfi luciferase. Coelenterazine and its luciferase was found in all (8 species) the luminous copepods examined.

A. K. Campbell; P. J. Herring

1990-01-01

42

Differential dormancy of co-occurring copepods  

NASA Astrophysics Data System (ADS)

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

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

1998-08-01

43

Copepod Population-Specific Response to a Toxic Diatom Diet  

PubMed Central

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

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

2012-01-01

44

Histological Characteristics of Abnormal Protrusions on Copepods from Lake Michigan, USA  

E-print Network

314 Histological Characteristics of Abnormal Protrusions on Copepods from Lake Michigan, USA. Cavaletto and Suzanne S. Tyler (2004) Histological characteristics of abnormal protrusions on copepods from histologically identified as ellobiopsid parasites. Other protrusions had a histology that suggested ellobiopsid

45

Hydrocarbon Contamination Decreases Mating Success in a Marine Planktonic Copepod  

PubMed Central

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

Seuront, Laurent

2011-01-01

46

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

Microsoft Academic Search

Large-scale variability in copepod abundance, size structure, and ingestion rates on phytoplankton was investigated during the cruise Atlantic Meridional Transect-13. The main aim of the study was to assess the relative importance of small copepods and copepod nauplii in different regions (Temperate N and S, Oligotrophic N and S, Equatorial and Mauritanian upwelling). Samples were fractionated into four size fractions

Eva López; Ricardo Anadón

2008-01-01

47

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

48

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

PubMed Central

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

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

2014-01-01

49

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

PubMed

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

Hu, Simin; Guo, Zhiling; Li, Tao; Carpenter, Edward J; Liu, Sheng; Lin, Senjie

2014-01-01

50

KARYOLOGICAL STUDY OF THE CALANOID COPEPOD 'EURYTEMORA AFFINIS'  

EPA Science Inventory

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

51

Accumulation of trace elements in a marine copepod  

Microsoft Academic Search

We measured assimilation efficiencies (AEs) from ingested algal food, uptake rates from the dissolved phase, and efflux rate constants of five trace elements (Ag, Cd, Co, Se and Zn) in the marine copepod Temora longicornis. AEs of Ag, Cd, Co, Se, and Zn from two diatom diets were 13, 35, 14, 59, and 61%, respectively. AEs of metals from ingested

Wen-Xiong Wang; Nicholas S. Fisher

1998-01-01

52

Chemosensory Grazing by Marine Calanoid Copepods (Arthropoda: Crustacea)  

Microsoft Academic Search

In laboratory experiments, mixed populations of two marine copepods (Acartia clausi and Eurytemora herdmani) when fed artificial food particles consisting of microcapsules that were either enriched with an encapsulated homogenate of naturally occurring phytoplankton or nonenriched preferentially ingested the enriched capsules. Beads or nonenriched capsules were either seldom ingested or not ingested at all. The observations demonstrate that filter-feeding in

S. A. Poulet; P. Marsot

1978-01-01

53

Chemoreceptors and Feeding in Calanoid Copepods (Arthropoda: Crustacea)  

Microsoft Academic Search

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.

Marc M. Friedman; J. Rudi Strickler

1975-01-01

54

Dissolution of coccolithophorid calcite by microzooplankton and copepod grazing  

NASA Astrophysics Data System (ADS)

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.

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

2008-01-01

55

1999 Macmillan Magazines Ltd Copepods, the small planktonic crus-  

E-print Network

cope- pod populations that inhabit dangerous oceanic ecosystems. Using transmission electron microscopy. The dark layers appear to represent a fusion of the apposed intracellular surfaces of sheath- cell of cytoplasm between the membranous layers7 . Sheaths in copepods have extensive radial attach- ment zones

Lenz, Petra H.

56

Linkagesbetweenchemical andphysicalresponsesand  

E-print Network

,heterotrophic flagellates, ciliates, rotifers, small cyclopoid copepods, and Chaoborus. Heterotrophic activity, HPLC chlo, summer heterotrophic production, and microbial components of the food web, . Acknowledgments In addition

Wisenden, Brian D.

57

Human forcing of the copepod–fish–jellyfish triangular trophic relationship  

Microsoft Academic Search

Copepods, the most abundant planktonic metazoans, constitute an intermediate trophic position between phytoplankton and higher\\u000a trophic-level animals such as fish and jellyfish. Fish and jellyfish are adversaries because they often compete for prey copepods\\u000a and also can be prey of each other. The classical food chain represented by phytoplankton–copepod–fish is the main process\\u000a leading to efficient and sustainable production of

Shin-ichi Uye

2011-01-01

58

Spatial and Temporal Distributions of Live and Dead Copepods in the Lower Chesapeake Bay (Virginia, USA)  

Microsoft Academic Search

Hydrography and copepod abundances (Acartia tonsa, Eurytemora affinis, and nauplii) were regularly monitored for 2 years in sub-estuaries of the lower Chesapeake Bay. Copepod vital status was\\u000a determined using neutral red. Abundances of A. tonsa copepodites and nauplii peaked in late summer and were related to water temperature. E. affinis was present in early fall and winter–spring. Copepod carcasses were a

David T. Elliott; Kam W. Tang

2011-01-01

59

Circular Polarization of Transmitted Light by Sapphirinidae Copepods  

PubMed Central

Circularly polarized light, rare in the animal kingdom, has thus far been documented in only a handful of animals. Using a rotating circular polarization (CP) analyzer we detected CP in linearly polarized light transmitted through epipelagic free living Sapphirina metallina copepods. Both left and right handedness of CP was detected, generated from specific organs of the animal's body, especially on the dorsal cephalosome and prosome. Such CP transmittance may be generated by phase retardance either in the muscle fibers or in the multilayer membrane structure found underneath the cuticle. Although the role, if any, played by circularly polarized light in Sapphirinidae has yet to be clarified, in other animals it was suggested to take part in mate choice, species recognition, and other forms of communication. Highlights Planktonic Sapphirinidae copepods were found to circularly polarize the light passing through them. Circular polarization may be created by unique, multilayered features of the membrane structure found under their cuticle or by organized muscle fibers. PMID:24465916

Baar, Yuval; Rosen, Joseph; Shashar, Nadav

2014-01-01

60

Copepods induce paralytic shellfish toxin production in marine dinoflagellates  

PubMed Central

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

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

2006-01-01

61

Complex trophic interactions of calanoid copepods in the Benguela upwelling system  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

62

New evidence of the copepod maternal food effects on reproduction  

Microsoft Academic Search

Failure of female reproductive capacity in the copepod Calanus helgolandicus was related to number and combination of the phytoplankton species in the diets. The maternal food effects were detectable at different levels: fecundity, oogenesis and hatching. Fecundity and hatching were normal with two single (ca. Isochrysis galbana and Prorocentrum minimum) and one mixed (Phaeodactylum tricornutum+Dunaliella tertiolecta+Pavlova lutherii+I. galbana+P. minimum) diets.

Arnaud Lacoste; Serge A. Poulet; Anne Cueff; Gerhard Kattner; Adrianna Ianora; Mohamed Laabir

2001-01-01

63

Contrasting Ecosystem-Effects of Morphologically Similar Copepods  

PubMed Central

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

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

2011-01-01

64

Hydrodynamics and energetics of jumping copepod nauplii and copepodids.  

PubMed

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

Wadhwa, Navish; Andersen, Anders; Kiørboe, Thomas

2014-09-01

65

The insidious effect of diatoms on copepod reproduction  

NASA Astrophysics Data System (ADS)

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.

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

66

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...

67

Seasonal feeding and fecundity of the calanoid copepod Acartia tonsa in Long Island Sound: is omnivory important to egg production?  

Microsoft Academic Search

Many suspension-feeding copepods show omnivorous feeding behavior. However, the relative contribution to egg production of herbivorous and heterotrophic feeding in copepods remains an open question. In this study, we quantified pigment ingestion rates and egg production rates of the planktonic calanoid copepod Acartia tonsa from July to November of 1986 in Long Island Sound, a large temperate estuary. Pigment ingestion

Hans G. Dam; William T. Peterson; Diane C. Bellantoni

1994-01-01

68

Ergasilid copepods (Poecilostomatoida) from the gills of primitive Mugilidae (grey mullets)  

Microsoft Academic Search

All representatives of the subfamily Agonostominae of grey mullets in the collections of The Natural History Museum in London were examined for parasitic copepods. Agonostomus monticola, Joturus pichardi, Aldrichetta forsteri and Cestraeus goldiei were all infected by copepods. Three new species of Acusicola and two new species of Ergasilus were found: E. parabahiensis n. sp. on A. monticola from Guyana

H. El-Rashidy; G. A. Boxshall

1999-01-01

69

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

70

Survival of copepods passing through a nuclear power station on northeastern Long Island Sound, USA  

Microsoft Academic Search

About 70% of the copepods entering the cooling water system of a nuclear power plant on northeastern Long Island Sound (USA) are not returned to the Sound in the effluent. Copepod mortalities are caused by the mechanical or hydraulic stresses of passage, although our experimental design could not determine whether heat or chlorination could cause mortality in the absence of

E. J. Carpenter; B. B. Peck; S. J. Anderson

1974-01-01

71

Active swimming in meiobenthic copepods of seagrass beds: geographic comparisons of abundances and reproductive characteristics  

Microsoft Academic Search

The entry of meiobenthic copepods from sediments or seagrass blades into the water column and reproductive characteristics of actively migrating fauna were investigated from 1981–1986 in a temperate intertidal Zostera capricorni seagrass bed in Pautahanui Inlet, New Zealand and in a subtidal Thalassia testudinum bed in Tampa Bay, Florida, USA. Emergence of copepods in New Zealand varied over a tidalcycle,

S. S. Bell; G. R. F. Hicks; K. Walters

1988-01-01

72

Local Recreational Parks as Hospitable Habitats for Small Aquatic Animals: Examples of Copepod Crustaceans in Virginia  

Microsoft Academic Search

Copepod microcrustaceans were collected from wetlands in five county parks and one privately managed neighborhood park in the Piedmont region of Virginia. A total of 43 species was found, 9 to 19 copepod species in each park. First state records were established for 16 species: Acanthocyclops brevispinosus, A. exilis, A. parasensitivus, A. robustus, Ectocyclops phaleratus, Eucyclops conrowae, Itocyclops yezoensis, Megacyclops

Janet W. Reid

73

COPEPODS AND SCOMBRID FISHES: A STUDY IN HOST-PARASITE RELATIONSHIPS  

E-print Network

COPEPODS AND SCOMBRID FISHES: A STUDY IN HOST-PARASITE RELATIONSHIPS ROGER F. CRESSEY,I BRUCE B. COLLE'ITE,' AND JOSEPH L. Russo' ABSTRACT Host specificity ofthe copepods parasitic on scombrid fishes is the basis for an analysis ofthe host-parasite relationship. A total of 46 different species of parasitic

74

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

NASA Astrophysics Data System (ADS)

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

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

75

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

76

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

77

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

NASA Astrophysics Data System (ADS)

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

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

2005-02-01

78

Invertebrate predation on planktonic rotifers  

Microsoft Academic Search

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

Craig E. Williamson

1983-01-01

79

Macroevolutionary patterns of sexual size dimorphism in copepods.  

PubMed

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

Hirst, Andrew G; Kiørboe, Thomas

2014-09-22

80

Escape strategies in co-occurring calanoid copepods  

Microsoft Academic Search

Abstract We show,how,four co-occurring calanoid,copepod,species modulate,their responses,to two,contrasting hydrodynamic,stimuli. Species-specific patterns,in escape,behavior,included,quantitative,differences,in performance to each stimulus type. Using high-speed video, we compared escape reactions in Acartia hudsonica, Centropages hamatus, Tortanus discaudatus, and Temora longicornis. Responses to a flow field created by a suction tube involved,reorientation away,from,the source of suction followed,by a series of vigorous,power,strokes. Responses,to brief computer-controlled hydrodynamic,stimuli had,short latencies

Daniel S. Burdick; Daniel K. Hartline; Petra H. Lenz

81

Assimilation and regeneration of trace elements by marine copepods  

USGS Publications Warehouse

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

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

1996-01-01

82

Marine copepod diversity patterns and the metabolic theory of ecology.  

PubMed

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

Rombouts, Isabelle; Beaugrand, Grégory; Iba?ez, Frédéric; Chiba, Sanae; Legendre, Louis

2011-06-01

83

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

USGS Publications Warehouse

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

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

2003-01-01

84

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

85

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

PubMed Central

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

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

2012-01-01

86

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

87

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

PubMed

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

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

2012-11-01

88

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

89

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

PubMed Central

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

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

2010-01-01

90

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

PubMed

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

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

2014-04-01

91

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

PubMed

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

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

2010-01-01

92

Feeding ecology of Spinocalanus antarcticus , a mesopelagic copepod with a looped gut  

Microsoft Academic Search

Spinocalanus antarcticus, an abundant mesopelagic copepod in polar seas, has a greatly elongated and looped midgut, contrary to most other copepod species. The total gut length is 1.77, 1.86 and 1.90 times the total body length in adult females, CV and CIV, respectively. Gross morphology of the midgut is similar in all copepodite stages and adults. It is described here

K. Kosobokova; H.-J. Hirche; T. Scherzinger

2002-01-01

93

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

E-print Network

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

Brown, Eric Kingsbury

1986-01-01

94

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

Microsoft Academic Search

Marine zooplanktic organisms, such as copepods, are usually associated with large numbers of bacteria. Some of these bacteria\\u000a live attached to copepods’ exoskeleton, while others prevail in their intestine and faecal pellets. Until now, general conclusions\\u000a concerning the identity of these bacteria are problematic since the majority of previous studies focused on cultivable bacteria\\u000a only. Hence, to date little is

Gunnar Gerdts; Maarten Boersma; Karen H. Wiltshire; Antje Wichels

2010-01-01

95

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

PubMed

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

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

2011-10-01

96

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

PubMed Central

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

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

2012-01-01

97

Effect of algal and animal diets on life history of the freshwater copepod Eucyclops serrulatus (Fischer, 1851)  

Microsoft Academic Search

We studied the survivorship and reproduction of the cyclopoid Eucyclops serrulatus using four diet types: algae Chlorella vulgaris and Scenedesmus acutus separately and each together with the rotifer Brachionus havanaensis. We used equal biomass (3.9 mg C l?1) of C. vulgaris and S. acutus while B. havanaensis was offered at a density of 0.5 ind. ml?1. Regardless of the food type, the average lifespan of

S. Nandini; S. S. S. Sarma

2007-01-01

98

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

PubMed

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

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

2014-01-01

99

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...

100

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

NASA Astrophysics Data System (ADS)

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', ?*) and beta diversity (MVDISP, ?, ?-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 functional diversity of copepods revealed features of an effective niche sharing and efficient utilization of the coastal resources by the resident zooplankton some of which are brought out for the first time showing a tropical estuary under the influence of monsoons. The present study also illustrates the importance of, and advocates the need for, incorporating complementary or additional biodiversity measures while describing biotic communities vis-à-vis environmental gradients.

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

2013-07-01

101

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

PubMed

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

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

2014-08-01

102

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

PubMed

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

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

2015-02-01

103

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

PubMed

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

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

2014-11-21

104

On the role of copepod antennae in the production of hydrodynamic force during hopping.  

PubMed

We integrate high-resolution experimental observations of a freely hopping copepod with three-dimensional numerical simulations to investigate the role of the copepod antennae in production of hydrodynamic force during hopping. The experimental observations revealed a distinctive asymmetrical deformation of the antennae during the power and return strokes, which lead us to the hypothesis that the antennae are active contributors to the production of propulsive force with kinematics selected in nature in order to maximize net thrust. To examine the validity of this hypothesis we carried out numerical experiments using an anatomically realistic, tethered, virtual copepod, by prescribing two sets of antenna kinematics. In the first set, each antenna moves as a rigid, oar-like structure in a reversible manner, whereas in the second set, the antenna is made to move asymmetrically as a deformable structure as revealed by the experiments. The computed results show that for both cases the antennae are major contributors to the net thrust force during hopping, and the results also clearly demonstrate the significant hydrodynamic benefit in terms of thrust enhancement and drag reduction derived from the biologically realistic, asymmetric antenna motion. This finding is not surprising given the low local Reynolds number environment within which the antenna operates, and points to striking similarities between the copepod antenna motion and ciliary propulsion. Finally, the simulations provide the first glimpse into the complex, highly 3-D structure of copepod wakes. PMID:20709931

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

2010-09-01

105

Evaluating Satiated Copepod Behavioral Responses to Thin Layer Flow Structure  

NASA Astrophysics Data System (ADS)

Zooplankton exploit a variety of chemical and fluid mechanical cues in foraging, mate-seeking, and habitat partitioning contexts. To examine the influence of environmental cues on zooplankton aggregations in coastal marine thin layers, a laboratory thin layer mimic was built. The apparatus uses a laminar, planar jet (the Bickley jet) to produce ecologically-relevant layers of chemical (beneficial and harmful phytoplankton) and fluid mechanical (shear strain rate) cues for zooplankton behavioral assays. Particle image velocimetry (PIV) and laser-induced fluorescence (LIF) were employed to fully quantify the spatial structure of the chemical and fluid mechanical cues, ensuring a close match to in situ conditions and allowing for investigations into threshold cue levels responsible for inducing behavioral responses. Evaluating the effect of hunger level on behavioral responses is particularly important for producing accurate individual-based simulations of zooplankton population dynamics. Behavioral assays with the calanoid copepod Temora longicornis have produced digitized trajectories and, subsequently, path kinematics. Observed behaviors include increased turn frequency and decreased relative swimming speed, which result in increased residence time in the free jet shear layer. Cue-induced individual behaviors have the potential to produce population-scale aggregations.

True, Aaron C.; Webster, Donald R.; Weissburg, Marc J.; Yen, Jeannette

2011-11-01

106

Trampling on coral reefs: tourism effects on harpacticoid copepods  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

107

Impacts of copepods on marine seston, and resulting effects on Calanus finmarchicus RNA:DNA ratios in mesocosm experiments  

Microsoft Academic Search

We investigated the impact of copepods on the seston community in a mesocosm set-up, and assessed how the changes in food quantity, quality and size affected the condition of the grazers, by measuring the RNA:DNA ratios in different developmental stages of Calanus finmarchicus. Manipulated copepod densities did not affect the particulate carbon concentration in the mesocosms. On the other hand,

C. Becker; D. Brepohl; H. Feuchtmayr; E. Zöllner; F. Sommer; C. Clemmesen; U. Sommer; M. Boersma

2005-01-01

108

Copepod biodiversity as an indicator of changes in ocean and climate conditions of the northern California current ecosystem  

Microsoft Academic Search

We evaluated copepod taxonomic diversity as a potential biological indicator of ocean conditions in the northeast Pacific Ocean using data collected biweekly between May 1996 and December 2004 and from 1969 to 1973 and 1983 off Newport, Oregon. During the summer, low copepod biodiversity is accompanied by high biomass, with the opposite patterns prevailing in the winter. High biodiversity, and

Rian C. Hooff; William T. Peterson

2006-01-01

109

Salinity tolerance of the copepod Apocyclops dengizicus (Lepeschkin, 1900), a key food chain organism in the Salton Sea, California  

Microsoft Academic Search

The copepod Apocyclops dengizicus is a key item in the food chain of the Salton Sea where the salinity is currently 45 g 1-1. The salinity of the Salton Sea may reach 90 g 1 -1 within the next 20 years. This study examined the salinity tolerance of this copepod.

Deborah M. Dexter

1993-01-01

110

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

E-print Network

Life history and biogeography of Calanus copepods in the Arctic Ocean: An individual-based modeling to penetrate, survive, and colonize the Arctic Ocean under present conditions of temperature, food availability transport of the copepods into the Arctic Ocean during the growing season or even during the following

Chen, Changsheng

111

Wax esters in tropical zooplankton and nekton and the geographical distribution of wax esters in marine copepods  

Microsoft Academic Search

Analyses of zooplankton and nekton from the central South Pacific showed that surface an d epipclagic zooplankton had small amounts of neutral lipids, mainly triglyccridcs, while deep-water tropical copepods had wax esters as the major lipid type, presumed to function as a rcscrvc srtoragc. The total lipid content and wax esters of tropical copepods captured at about 500 m were

RICHARD F. LEE; JED HIROTA

1973-01-01

112

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...

113

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

NASA Astrophysics Data System (ADS)

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.

Shimanaga, Motohiro; Shirayama, Yoshihisa

2003-04-01

114

Food quality effects on copepod growth and development: implications for bioassays in ecotoxicological testing.  

PubMed

We evaluated effects of six algal species in 25 combinations on growth and reproduction of the harpacticoid copepod Nitocra spinipes. In the first lifecycle test, Rhodomonas salina, Phaeodactylum tricornutum, and Dunaliella tertiolecta were used. The results showed that R. salina was the best food, whereas P. tricornutum (0% development success) and D. tertiolecta (41.7% malformations) were poor food items. In the second lifecycle test, a mixture of R. salina, Tetraselmis suecica, and Thalassiosira weisflogii (selected from screening tests) was tested together with a mono-diet of R. salina. Also in this test, copepods fed R. salina performed better (i.e. had higher survival and reproductive success) compared with the other treatment. We conclude that R. salina is appropriate to use as food in toxicity testing with N. spinipes, whereas some of the algae commonly used as feed in ecotoxicological tests with other copepods had detrimental effects on the development, reproduction, and survival of N. spinipes. PMID:18514311

Dahl, Ulrika; Lind, Charlotta Rubio; Gorokhova, Elena; Eklund, Britta; Breitholtz, Magnus

2009-02-01

115

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

116

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

PubMed Central

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

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

2014-01-01

117

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

USGS Publications Warehouse

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.

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

2004-01-01

118

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

PubMed

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

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

2014-06-01

119

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

PubMed Central

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

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

2012-01-01

120

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

PubMed

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

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

2014-02-01

121

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

PubMed

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

Hirose, Euichi; Uyeno, Daisuke

2014-08-01

122

PHYSICAL CONTROLS ON DENSE COPEPOD AGGREGATIONS IN THE GREAT SOUTH CHANNEL  

E-print Network

WHOI PHYSICAL OCEANOGRAPHY 3 WHOI BIOLOGY 4 NORTH CAROLINA STATE UNIVERSITY CONTACT INFO: NWOODS@WHOI.EDU 1 INTRODUCTION Each spring many important fish and whale species, including the endangered North Atlantic right whale, feed on dense aggregations of copepods in the Great South Channel (GSC

Fratantoni, David

123

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

124

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

PubMed

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 (ClO?) was used as a disinfectant. We also assessed the effects of the ClO?dosage, 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 ClO?dose 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 ClO?was 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

Lin, Tao; Chen, Wei; Cai, Bo

2014-01-01

125

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

EPA Science Inventory

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

126

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

EPA Science Inventory

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

127

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

128

Genetic Consequences of Many Generations of Hybridization Between Divergent Copepod Populations  

Microsoft Academic Search

Crosses between populations of the copepod Tigriopus californicus typically result in outbreeding depression. In this study, replicate hybrid populations were initiated with first generation backcross hybrids between two genetically distinct populations from California: Royal Palms (RP) and San Diego (SD). Reciprocal F1 were backcrossed to SD, resulting in expected starting frequencies of 25% RP\\/75% SD nuclear genes on either a

S. EDMANDS; H. V. FEAMAN; J. S. HARRISON; C. C. TIMMERMAN

2005-01-01

129

Importance of wax esters and other lipids in the marine food chain: Phytoplankton and copepods  

Microsoft Academic Search

Wax esters, which function as reserve fuels, account for 25 to 40% of the lipid of the pelagic copepod Calanus helgolandicus (Copepoda, Calanoida). In laboratory experiments with these crustaceans, diatoms (Lauderia borealis, Chaetoceros curvisetus, and Skeletonema costatum) and dinoflagellates (Gymnodinium splendens), which contained no wax esters, were used as food. Changes in the food concentration affected both the amount of

R. F. Lee; J. C. Nevenzel; G.-A. Paffenhöfer

1971-01-01

130

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

131

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

132

Effect of salinity variation and pesticide exposure on an estuarine harpacticoid copepod, Microarthridion  

E-print Network

Effect of salinity variation and pesticide exposure on an estuarine harpacticoid copepod worse than females in all treatments, with none surviving pesticide exposure at 45 Ag/l CHPY and 6 Ag Microarthridion littorale (Poppe) was tested for interaction effects between salinity change and acute pesticide

Staton, Joe

133

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

PubMed Central

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

Sell, A F

2000-01-01

134

A Review of the Biology of the Parasitic Copepod Lernaeocera branchialis (L., 1767) (Copepoda: Pennellidae)  

Microsoft Academic Search

This review concerns the parasitic marine copepod Lernaeocera branchialis (L., 1767) and provides an overview of current knowledge concerning its biology and host–parasite interactions. The large size and distinctive appearance of the metamorphosed adult female stage, coupled with the wide exploitation and commercial importance of its final gadoid hosts, means that this species has long been recognised in the scientific

Adam J. Brooker; Andrew P. Shinn; James E. Bron

2007-01-01

135

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

PubMed Central

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

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

2013-01-01

136

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

Microsoft Academic Search

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

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

2001-01-01

137

The copepods associated with the coral Astroides calycularis (Scleractinia, Dendrophyllidae) in the Strait of Gibraltar  

Microsoft Academic Search

This paper describes and provides new records of the copepods hosted by the ahermatypic scleractinian Astroides calycularis (Pallas, 1766). This coral species is endemic to the Mediterranean Sea and protected by the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). The coral colonies were collected at both sides of the Strait of Gibraltar. Two new

Mercedes Conradi; Ma Eugenia Bandera

2006-01-01

138

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

PubMed

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

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

2003-05-01

139

?-Naphthoflavone induces oxidative stress in the intertidal copepod, Tigriopus japonicus.  

PubMed

?-Naphtoflavone (?-NF) is a flavonoid and enhances oxidative stress in vertebrates with little information from aquatic invertebrates as yet. In this study, we investigated the effects of ?-NF on the antioxidant defense systems of the intertidal copepod Tigriopus japonicus. To measure the ?-NF-triggered changes in oxidative stress markers, such as intracellular reactive oxygen species (ROS), glutathione (GSH) concentration, residual glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR), and superoxide dismutase (SOD) activity, T. japonicus were exposed to ?-NF (0.5 and 1 mg/L) for 72 h. Significant (P?

Rhee, Jae-Sung; Lee, Young-Mi; Kim, Bo-Mi; Leung, Kenneth Mei Yee; Kim, Il-Chan; Yim, Joung Han; Lee, Jae-Seong

2015-03-01

140

Vertical zonation and distributions of calanoid copepods through the lower oxycline of the Arabian Sea oxygen minimum zone  

NASA Astrophysics Data System (ADS)

This paper provides the first comprehensive analysis of calanoid copepod vertical zonation and community structure at midwater depths (300-1000 m) through the lower oxygen gradient (oxycline) (0.02 to ?0.3 ml/L) of an oxygen minimum zone (OMZ). Feeding ecology was also analyzed. Zooplankton were collected with a double 1 m 2 MOCNESS plankton net in day and night vertically-stratified oblique tows from 1000 m to the surface at six stations during four seasons as part of the 1995 US Joint Global Ocean Flux Study (JGOFS) Arabian Sea project. The geographic comparison between a eutrophic more oxygenated onshore station and an offshore station with a strong OMZ served as a natural experiment to elucidate the influence of depth, oxygen concentration, season, food resources, and predators on the copepod distributions. Copepod species and species assemblages of the Arabian Sea OMZ differed in their spatial and vertical distributions relative to environmental and ecological characteristics of the water column and region. The extent and intensity of the oxycline at the lower boundary of the OMZ, and its spatial and temporal variability over the year of sampling, was an important factor affecting distributional patterns. Calanoid copepod species showed vertical zonation through the lower OMZ oxycline. Clustering analyses defined sample groups with similar copepod assemblages and species groups with similar distributions. No apparent diel vertical migration for either calanoid or non-calanoid copepods at these midwater depths was observed, but some species had age-related differences in vertical distributions. Subzones of the OMZ, termed the OMZ Core, the Lower Oxycline, and the Sub-Oxycline, had different copepod communities and ecological interactions. Major distributional and ecological changes were associated with surprisingly small oxygen gradients at low oxygen concentrations. The calanoid copepod community was most diverse in the most oxygenated environments (oxygen >0.14 ml/L), but the rank order of abundance of species was similar in the Lower Oxycline and Sub-Oxycline. Some species were absent or much scarcer in the OMZ Core. Two copepod species common in the Lower Oxycline were primarily detritivorous but showed dietary differences suggesting feeding specialization. The copepod Spinocalanus antarcticus fed primarily on components of the vertical particulate flux and suspended material, a less versatile diet than the co-occurring copepod Lucicutia grandis. Vertical zonation of copepod species through the lower OMZ oxycline is probably a complex interplay between physiological limitation by low oxygen, potential predator control, and potential food resources. Pelagic OMZ and oxycline communities, and their ecological interactions in the water column and with the benthos, may become even more widespread and significant in the future ocean, if global warming increases the extent and intensity of OMZs as predicted.

Wishner, Karen F.; Gelfman, Celia; Gowing, Marcia M.; Outram, Dawn M.; Rapien, Mary; Williams, Rebecca L.

2008-08-01

141

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

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

142

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

NASA Astrophysics Data System (ADS)

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.

Homma, Tomoe; Yamaguchi, Atsushi

2010-08-01

143

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

144

Vertical distribution of mesozooplankton in the coastal Canadian Beaufort Sea in summer  

NASA Astrophysics Data System (ADS)

This paper contributes to baseline knowledge of lower trophic levels that is necessary to monitor the impact of oil and gas development on the Canadian Beaufort Sea ecosystem. As part of the Nahidik Program, the vertical distribution of mesozooplankton was studied along two transects in the coastal Canadian Beaufort Sea in the summer of 2009. Mesozooplankton was collected with 153 ?m conical net in two hydrologically distinct layers - the upper layer which was fresher and warmer due to the Mackenzie River runoff, and the lower layer which was colder and more saline. Two separate mesozooplankton assemblages were distinguished in the individual layers. The average zooplankton abundance in the two layers was 3120 ± 2860 ind. m- 3 and 4200 ± 5550 ind. m- 3 in the upper and lower layer, respectively. The upper layer was largely inhabited by meroplanktonic Polychaeta (752 ± 1038 ind. m- 3) and Bivalvia larvae (228 ± 307 ind. m- 3) as well as by youngest stages of Pseudocalanus spp. (245 ± 499 ind. m- 3). Conversely, the lower layer was mainly occupied by typical marine taxa such as Calanus glacialis (95 ± 76 ind. m- 3), C. hyperboreus (27 ± 12 ind. m- 3) and Triconia borealis (111 ± 81 ind. m- 3). Oithona similis, a widely distributed eurytopic cyclopoid copepod, showed no consistent pattern of vertical distribution (280 and 291 ind. m- 3, in the lower and upper layer, respectively).

Walkusz, Wojciech; Williams, William J.; Kwasniewski, Slawomir

2013-11-01

145

Attack or attacked: the sensory and fluid mechanical constraints of copepods' predator-prey interactions.  

PubMed

Many animals are predator and prey at the same time. This dual position represents a fundamental dilemma because gathering food often leads to increased exposure to predators. The optimization of the tradeoff between eating and not being eaten depends strongly on the sensing, feeding, and mechanisms for mobility of the parties involved. Here, I describe the mechanisms of sensing, escaping predators, and capturing prey in marine pelagic copepods. I demonstrate that feeding tradeoffs vary with feeding mode, and I describe simple fluid mechanical models that are used to quantify these tradeoffs and review observations and experiments that support the assumptions and test the predictions. I conclude by presenting a mechanistically underpinned model that predicts optimal foraging behaviors and the resulting size-scaling and magnitude of copepods' clearance rates. PMID:23613321

Kiørboe, Thomas

2013-11-01

146

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

147

Harpacticoid copepods (Thalestridae) infesting the cultivated Wakame (brown alga, Undaria pinnatifida) in Korea  

Microsoft Academic Search

Two species of thalestrid harpacticoid: Amenophia orientalis n. sp. and Parathalestris infestus n. sp., are described based on specimens collected from Soando Island in Korea. These copepods infest the cultivated brown alga, Wakame, Undaria pinnatifida (Harvey), producing galls with pinholes (0·5–1·1.5 mm in diameter) on the fronds, midribs, and sporophylls. A. orientalis outnumbered P. infestus in all of the observed

Ju-Shey Ho; Jae-Sang Hong

1988-01-01

148

Day\\/night differences in the grazing impact of marine copepods  

Microsoft Academic Search

Day\\/night differences in the removal rate of phytoplankton can occur as a result of increased copepod grazing rates at certain times of the day and diel vertical migration of animals. We conducted shipboard grazing experiments and fine-scale vertical zooplankton sampling to resolve these behaviors. Day\\/night feeding differences were compared in the center of several warm-core Gulf Stream rings, under conditions

Michael R. Roman; Kathyrn A. Ashton; Anne L. Gauzens

1988-01-01

149

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

Microsoft Academic Search

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

Ulrich Sommer; Frank Sommer

2006-01-01

150

Copepod Community Changes in the Southern East China Sea between the Early and Late Northeasterly Monsoon  

Microsoft Academic Search

Yang-Chi Lan, Ming-An Lee, Cheng-Hsin Liao, Wen-Yu Chen, Ding-An Lee, Deng-Cheng Liu, and Wei- Cheng Su (2008) Copepod community changes in the southern East China Sea between the early and late northeasterly monsoon. Zoological Studies 47(1): 61-74. Weather conditions in our study area during the northeasterly (NE) monsoon season are usually rough, and it is difficult to sample on board

Yang-Chi Lan; Ming-An Lee; Cheng-Hsin Liao; Wen-Yu Chen; Ding-An Lee; Deng-Cheng Liu; Wei-Cheng Su

2008-01-01

151

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

PubMed Central

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

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

2011-01-01

152

SubLethal Effects of Elevated Concentration of CO 2 on Planktonic Copepods and Sea Urchins  

Microsoft Academic Search

Data concerning the effects of high CO2 concentrations on marine organisms are essential for both predicting future impacts of the increasing atmospheric CO2 concentration and assessing the effects of deep-sea CO2sequestration. Here we review our recent studies evaluating the effects of elevated CO2 concentrations in seawater on the mortality and egg production of the marine planktonic copepod, Acartia steueri, and

Haruko Kurihara; Shinji Shimode; Yoshihisa Shirayama

2004-01-01

153

Effects of elevated CO2 on the reproduction of two calanoid copepods.  

PubMed

Some planktonic groups suffer negative effects from ocean acidification (OA), although copepods might be less sensitive. We investigated the effect of predicted CO2 levels (range 480-750ppm), on egg production and hatching success of two copepod species, Centropages typicus and Temora longicornis. In these short-term incubations there was no significant effect of high CO2 on these parameters. Additionally a very high CO2 treatment, (CO2=9830ppm), representative of carbon capture and storage scenarios, resulted in a reduction of egg production rate and hatching success of C. typicus, but not T. longicornis. In conclusion, reproduction of C. typicus was more sensitive to acute elevated seawater CO2 than that of T. longicornis, but neither species was affected by exposure to CO2 levels predicted for the year 2100. The duration and seasonal timing of exposures to high pCO2, however, might have a significant effect on the reproduction success of calanoid copepods. PMID:23490345

McConville, Kristian; Halsband, Claudia; Fileman, Elaine S; Somerfield, Paul J; Findlay, Helen S; Spicer, John I

2013-08-30

154

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

155

Better red than dead? Potential aposematism in a harpacticoid copepod, Metis holothuriae.  

PubMed

The conspicuous, red harpacticoid Metis holothuriae grows to a large size (?600 ?m length) and accounts for 29.51% of the numerical meiofaunal abundance within blooms of the toxic, benthic cyanobacterium Lyngbya majuscula. Despite this, the meiobenthic juvenile trumpeter whiting, Sillago maculata, consume M. holothuriae at only 2.16% of numerical meiofaunal biomass within simulated blooms, despite their apparent ease of predation. We compared the predation rates of copepods that had been dyed red (primarily Canuellidae and not known to be toxic) to M. holothuriae by S. maculata, to assess whether avoidance by predators is possibly a response to an aposematic signal conveyed by the colouration of the copepods and reinforced by their potential toxicity from exposure to L. majuscula. M. holothuriae were again strongly avoided, with only 6.25% of M. holothuriae consumed, whereas dyed copepods were consumed with relative alacrity, indicating that predation was not deterred by colouration alone. M. holothuriae copepodites were consumed in preference to adult individuals, supporting the idea that toxin accumulation or other factors relating to maturation might explain avoidance by benthivorous fishes. PMID:22209520

Gilby, Ben L; Burfeind, Dana D; Tibbetts, Ian R

2012-03-01

156

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

PubMed

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

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

2013-10-01

157

Habitat temperature is an important determinant of cholesterol contents in copepods  

PubMed Central

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

Hassett, R. Patrick; Crockett, Elizabeth L.

2009-01-01

158

Sublethal stress: Impact of solar UV radiation on protein synthesis in the copepod Acartia tonsa  

PubMed Central

Aquatic organisms respond to environmental challenges such as thermal stress with the rapid induction of highly conserved polypeptides known as stress proteins or heat shock proteins (Hsps). Solar ultraviolet radiation (UVR, 280–400 nm) is an important environmental stressor in marine ecosystems. Here, we present results of experiments conducted with the marine copepod Acartia tonsa to follow the de novo protein synthesis and measure the level of constitutive and inducible isoforms of the Hsp70 gene family of stress proteins after UV exposure. Animals were collected from Tampa Bay, Florida (USA), and exposed to solar radiation (full spectrum), UV-A (320–400 nm) and PAR (400–700 nm), or PAR only, for periods of 0.5–4 h. Controls were kept in the dark. Protein synthesis was robust under all treatments when the copepods were exposed to low solar radiation intensities. Conversely, high solar radiation intensities (both UV-B and UV-A) caused an overall suppression in the protein synthesis of the copepods with no detectable induction of stress-inducible isoforms of Hsps. Immunochemical assays (western blotting) showed that UVR increased levels (3.5–4-fold increase compared to the dark control) of the constitutively expressed 70 kDa heat-shock (Hsc70) protein in A. tonsa, without indication of inducible isoform upregulation. PMID:21258623

Tartarotti, Barbara; Torres, Joseph J.

2011-01-01

159

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

PubMed

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

Hudson, Patrick L; Bowen, Charles A

2002-08-01

160

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

PubMed

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

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

2014-12-01

161

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

PubMed Central

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

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

2013-01-01

162

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

PubMed Central

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

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

2013-01-01

163

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

PubMed Central

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

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

2013-01-01

164

Latitudinal differentiation in the effects of the toxic dinoflagellate Alexandrium spp. on the feeding and reproduction of populations of the copepod Acartia hudsonica  

Microsoft Academic Search

Blooms of the dinoflagellate Alexandrium spp. increase in their frequency, toxicity and historical presence with increasing latitude from New Jersey (USA) to the Gaspé peninsula (Canada). Biogeographic variation in these blooms results in differential exposure of geographically separate copepod populations to toxic Alexandrium. We hypothesize that the ability of copepods to feed and reproduce on toxic Alexandrium should be higher

Sean P. Colin; Hans G. Dam

2002-01-01

165

The effect of temperature, and food quantity and quality on the growth and development rates in laboratory-cultured copepods and cladocerans from a Sri Lankan reservoir  

Microsoft Academic Search

Length growth, instar durations, fecundity and mortality rates of fivespecies of microcrustacean zooplankton from a tropical reservoir weremeasured in relation to food quantity and temperature in laboratorycultures. Three cladocerans (Ceriodaphnia cornuta, Moina micrura,Diaphanosoma excisum), one calanoid copepod (Heliodiaptomus viduus), and onecyclopoid copepod (Mesocyclops thermocyclopoides) were studied. Filteredseston (45 µm mesh) from a local pond was used for food. Two foodconcentrations

P. Bandu Amarasinghe; Maarten Boersma; Jacobus Vijverberg

1997-01-01

166

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

NASA Astrophysics Data System (ADS)

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

Seuront, L.

2010-12-01

167

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

PubMed Central

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

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

2013-01-01

168

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

PubMed Central

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

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

2013-01-01

169

A metagenetic approach for revealing community structure of marine planktonic copepods.  

PubMed

Marine planktonic copepods are an ecologically important group with high species richness and abundance. Here, we propose a new metagenetic approach for revealing the community structure of marine planktonic copepods using 454 pyrosequencing of nuclear large subunit ribosomal DNA. We determined an appropriate similarity threshold for clustering pyrosequencing data into molecular operational taxonomic units (MOTUs) using an artificial community containing 33 morphologically identified species. The 99% similarity threshold had high species-level resolution for MOTU clustering but overestimated species richness. The artificial community was appropriately clustered into MOTUs at 97% similarity, with little inflation in MOTU numbers and with relatively high species-level resolution. The number of sequence reads of each MOTU was correlated with dry weight of that taxon, suggesting that sequence reads could be used as a proxy for biomass. Next, we applied the method to field-collected samples, and the results corresponded reasonably well with morphological analysis of these communities. Numbers of MOTUs were well correlated with species richness at 97% similarity, and large numbers of sequence reads were generally observed in MOTUs derived from species with large biomass. Further, MOTUs were successfully classified into taxonomic groups at the family level at 97% similarity; similar patterns of species richness and biomass were revealed within families with metagenetic and morphological analyses. At the 99% similarity threshold, MOTUs with high proportions of sequence reads were identified as biomass-dominant species in each field-collected sample. The metagenetic approach reported here can be an effective tool for rapid and comprehensive assessment of copepod community structure. PMID:24943089

Hirai, J; Kuriyama, M; Ichikawa, T; Hidaka, K; Tsuda, A

2015-01-01

170

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

PubMed

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 toxicity test with A. sinjiensis proved to be a valuable tool in these toxicity assessments, and is recommended for use in tropical marine toxicity assessments for northern Australia. PMID:23932510

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

2013-11-01

171

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

Microsoft Academic Search

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

Adriana C. Bejarano; G. Thomas Chandler

2003-01-01

172

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

PubMed

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

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

2014-09-01

173

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

PubMed Central

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

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

2013-01-01

174

Aldehyde suppression of copepod recruitment in blooms of a ubiquitous planktonic diatom  

NASA Astrophysics Data System (ADS)

The growth cycle in nutrient-rich, aquatic environments starts with a diatom bloom that ends in mass sinking of ungrazed cells and phytodetritus. The low grazing pressure on these blooms has been attributed to the inability of overwintering copepod populations to track them temporally. We tested an alternative explanation: that dominant diatom species impair the reproductive success of their grazers. We compared larval development of a common overwintering copepod fed on a ubiquitous, early-blooming diatom species with its development when fed on a typical post-bloom dinoflagellate. Development was arrested in all larvae in which both mothers and their larvae were fed the diatom diet. Mortality remained high even if larvae were switched to the dinoflagellate diet. Aldehydes, cleaved from a fatty acid precursor by enzymes activated within seconds after crushing of the cell, elicit the teratogenic effect. This insidious mechanism, which does not deter the herbivore from feeding but impairs its recruitment, will restrain the cohort size of the next generation of early-rising overwinterers. Such a transgenerational plant-herbivore interaction could explain the recurringly inefficient use of a predictable, potentially valuable food resource-the spring diatom bloom-by marine zooplankton.

Ianora, Adrianna; Miralto, Antonio; Poulet, Serge A.; Carotenuto, Ylenia; Buttino, Isabella; Romano, Giovanna; Casotti, Raffaella; Pohnert, Georg; Wichard, Thomas; Colucci-D'Amato, Luca; Terrazzano, Giuseppe; Smetacek, Victor

2004-05-01

175

Morphology of the deep-sea copepod Bobkabata kabatabobbus (Lernaeosoleidae: Poecilostomatoida) and amended diagnosis of Lernaeosoleidae.  

PubMed

New morphological information on the deep-sea parasitic copepod Bobkabata kabatabobbus Hogans and Benz, 1990 (Lernaeosoleidae: Poecilostomatoida) is provided based on 2 newly discovered, complete specimens collected from a pallid sculpin, Cottunculus thomsoni (Gunther, 1882), captured in water 1,463 m deep in Welker Canyon off Rhode Island (western North Atlantic). The first antennae of both specimens were tiny, indistinctly segmented, and armed with spiniform setae. Terminal segments of the second antennae were robust hooks and were impossible to disengage from the host without severing them from their basal sockets. A simple orifice without any associated appendages may have represented the mouth. Both specimens were transformed adult females and each was embedded in the flesh of their scaleless host up to where the pregenital trunk began to broaden into its characteristic horseshoe shape. Whereas each copepod's bulbous cephalothorax appeared to be the primary attachment device, the powerfully hooked second antennae seemed positioned to facilitate the application of the presumed mouth to the host. A revised family diagnosis for Lernaeosoleidae Hogans and Benz, 1990 is provided that primarily differentiates Lernaeosoleidae from the closely allied Chondracanthidae H. Milne-Edwards, 1840 and other poecilostomatoids based on the absence of mandibles, first and second maxillae, maxillipeds, and thoracic legs 1-4 in lernaeosoleids. PMID:9488347

Benz, G W; Braswell, J S

1998-02-01

176

Optimal foraging by a suspension-feeding copepod: responses to short-term and seasonal variation in food resources  

Microsoft Academic Search

Laboratory radioisotope experiments were used to investigate the effects of phytoplankton seasonal succession on the selectivity and clearance rates of a suspension-feeding copepod in two Indiana lakes. Responses to particle size and quality were tested by allowing adult female Diaptomus birgei feeding in natural seston to select between a small (6×7 µm) flagellate (Chlamydomonas reinhardii) and a large, poor quality

William R. DeMott

1995-01-01

177

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

Microsoft Academic Search

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

Mariana Reissig; Beatriz Modenutti; Esteban Balseiro; Claudia Queimaliños

2004-01-01

178

Ingestion of 15 N 2 -labelled Trichodesmium spp. and ammonium regeneration by the harpacticoid copepod Macrosetella gracilis  

Microsoft Academic Search

The pelagic harpacticoid copepod, Macrosetella gracilis (A. Scott), is found in association with colonies of the nitrogen-fixing (diazotrophic), bloomforming cyanobacterium Trichodesmium spp. in tropical and subtropical waters. M. gracilis is one of the few direct grazers of these often toxic cyanobacteria. Experiments investigating NH+4regeneration by M. gracilis were conducted in the Caribbean in September 1992 and the Coral Sea, Australia

J. M. O'Neil; P. M. Metzler; P. M. Glibert

1996-01-01

179

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

PubMed

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 ?g deltamethrin/L, 0.098-0.36 ?g 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

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

2014-10-01

180

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

181

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

EPA Science Inventory

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

182

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

SciTech Connect

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

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

2000-04-01

183

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

EPA Science Inventory

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

184

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

E-print Network

, transparency, vertical migration, spines, bioluminescent discharges, and in the case of marine copepods in the oceans and constitute a major trophic link in oceanic food webs. Calanoids respond to threats.g., Drenner et al. 1978; Viitasalo et al. 1998) and hence in their numerical success in the oceans. The motor

Hartline, Daniel K.

185

Toxin accumulation and feeding behaviour of the planktonic copepod Calanus finmarchicus exposed to the red-tide dinoflagellate Alexandrium excavatum  

Microsoft Academic Search

The planktonic copepod Calanus finmarchicus is a dominant member of the zooplankton community in the lower St. Lawrence Estuary in eastern Canada. Blooms of the toxic marine dinoflagellate Alexandrium excavatum which produces high cellular levels of paralytic shellfish poisoning (PSP) toxins, occur during the period of high C. finmarchicus production in summer in this region. To study the feeding behaviour

N. Turriff; J. A. Runge; A. D. Cerebella

1995-01-01

186

Colloidal organic carbon and trace metal (Cd, Fe, and Zn) releases by diatom exudation and copepod grazing  

Microsoft Academic Search

Colloidal macromolecular organic compounds are important intermediaries between solution and particle phases and play a critical role in the biogeochemistry of trace metals and organic carbon. The releases of colloidal organic carbon and trace metals (Cd, Fe, and Zn) mediated by copepod grazing and decomposition, and direct diatom exudation, were examined using a radiotracer approach. The colloidal phase was operationally

Wuchang Zhang; Wen-Xiong Wang

2004-01-01

187

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

EPA Science Inventory

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

188

The mesopelagic copepod Gaussia princeps (Scott) (Calanoida: Metridinidae) from the Western Caribbean with notes on integumental pore patterns  

Microsoft Academic Search

The mesopelagic calanoid copepod Gaussia princeps (Scott, 1894) was originally described from the eastern Atlantic. It has been recorded in tropical and subtropical latitudes of the world, but has been reported only occasionally from the northwestern tropical Atlantic (NWTA). Comparative morphological studies, particularly of males, have not included specimens from the NWTA. Based on a collection of zooplankton from the

EDUARDO SUÁREZ-MORALES

189

Prey capture of pike Esox lucius larvae in turbid water.  

PubMed

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

Salonen, M; Engström-Ost, J

2010-06-01

190

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

NASA Astrophysics Data System (ADS)

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

Yi, Xiaoyan; Zhang, Huan; Liu, Guangxing

2014-05-01

191

EFFECT OF SALINITY VARIATION AND PESTICIDE EXPOSURE ON AN ESTUARINE HARPACTICOID COPEPOD, MICROARTHRIDION LITTORALE (POPPE), IN THE SOUTHEASTERN US. (R827397)  

EPA Science Inventory

The harpacticoid copepod Microarthridion littorale (Poppe) was tested for interaction effects between salinity change and acute pesticide exposure on the survival and genotypic composition of a South Carolina population. Previous data suggested a significant link betwee...

192

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

NASA Astrophysics Data System (ADS)

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.

Elbrächter, Malte

1988-09-01

193

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

194

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

195

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

NASA Astrophysics Data System (ADS)

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

Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

2015-02-01

196

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

PubMed Central

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

Sereda, Sergej Vital’evi?; Wilke, Thomas; Schultheiß, Roland

2014-01-01

197

An assessment of three harpacticoid copepod species for use in ecotoxicological testing.  

PubMed

The relatively short life cycles of harpacticoid copepods makes them appropriate animals for use in tests that rapidly assess the acute, sublethal, or chronic effects of sediment contaminants. In this study, four harpacticoid copepod species (Nitocra spinipes, Tisbe tenuimana, Robertgurneya hopkinsi, and Halectinosoma sp.) were isolated from clean marine sediments, and procedures for laboratory culturing were developed. Halectinosoma sp. was abandoned due to handling difficulties. For the remaining species, the influence of food type and quantity on life-cycle progression was assessed. A mixed diet, comprising two species of algae (Tetraselmis sp. and Isochrysis sp.) and fish food (Sera Micron) was found to maintain healthy cultures and was fed during laboratory tests. Water-only exposure to dissolved copper (Cu) showed that the times (range) required to cause 50% lethality (LT(50)) were 24 (22-27) h at 50 ?g Cu/l for T. tenuimana; 114 (100-131) and 36 (32-40) h for 200 and 400 ?g Cu/l, respectively, for N. spinipes; and 119 (71-201) and 25 (18-33) h for 200 and 400 ?g Cu/l, respectively, for R. hopkinsi. 96-h LC(50) (concentration causing 50% lethality) were also determined for adult N. spinipes exposed to cadmium, copper, zinc, ammonia, and phenol. A ranking system was generated based on the ease handling and culturing, rate of maturity, food selectivity and sensitivity to Cu. From this ranking, N. spinipes was determined to be the most suitable species for use in developing sediment-toxicity tests. The measurement of total reproductive output of N. spinipes during 10-day exposure to whole sediment was found to provide a useful end point for assessing the effects of sediment contamination. PMID:21305275

Ward, Daniel J; Perez-Landa, Victor; Spadaro, David A; Simpson, Stuart L; Jolley, Dianne F

2011-10-01

198

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

PubMed

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

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

2014-09-01

199

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

NASA Astrophysics Data System (ADS)

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

Eisfeld, Sonja M.; Niehoff, Barbara

2007-09-01

200

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

NASA Astrophysics Data System (ADS)

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 ? 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 ? 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 ? 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 ? 15N values at the base of the food web, the isotopic difference between these two taxa, “ ?YFT-COP,” was interpreted as a trophic-position offset. Yellowfin tuna trophic-position estimates based on their bulk ? 15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore-offshore, east to west gradient in yellowfin tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of yellowfin tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin tuna stomach contents did not show a regular inshore-offshore gradient in trophic position during 2003-2005, but the trophic-position estimates based on both methods had similar scales of variability. We conclude that trophic status of yellowfin tuna increased significantly from east to west over the study area based on the spatial pattern of ?YFT-COP values and the difference between the ? 15N values of glutamic acid and glycine, “trophic” and “source” amino acids, respectively. These results provide improved depictions of trophic links and biomass flows for food-web models, effective tools to evaluate climate and fishing effects on exploited ecosystems.

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

201

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

PubMed

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 ?g/L. As shown in a chronic full life-cycle test, T. japonicus exposed to 1.0 ?g/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 ?g/L TPTCl; at or above which population extinction could occur. At 0.1 ?g/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

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

2014-09-01

202

Vulnerability of the copepod Acartia tonsa to predation by the scyphomedusa Chrysaora quinquecirrha?: effect of prey size and behavior  

Microsoft Academic Search

Although scyphomedusae have received increased attention in recent years as important predators in coastal and estuarine\\u000a environments, the factors affecting zooplankton prey vulnerability to these jellyfish remain poorly understood. Current models\\u000a predicting feeding patterns of cruising entangling predators, such as Chrysaora quinquecirrha (Desor, 1948), fail to account for the selection of fast-escaping prey such as copepods. Nevertheless, our analysis of

C. L. Suchman; B. K. Sullivan

1998-01-01

203

Linkage relationships among five enzyme-coding gene loci in the copepod Tigriopus californicus: A genetic confirmation of achiasmatic meiosis  

Microsoft Academic Search

Linkage relationships among five polymorphic enzyme-coding gene loci in the marine copepod Tigriopus californicus have been determined using electrophoretic analysis of progeny from laboratory matings. Phosphoglucose isomerase (PGI; EC 5.3.1.9) was found to be tightly linked to glutamate-pyruvate transaminase (GPT; EC 2.6.1.2), with only one recombinant observed in 364 progeny; glutamate-oxaloacetate transaminase (GOT; EC 2.6.1.1) is linked to the PGI-GPT

Ronald S. Burton; Marcus W. Feldman; Stephen G. Swisher

1981-01-01

204

Effects of toxic cyanobacteria and purified toxins on the survival and feeding of a copepod and three species of Daphnia  

Microsoft Academic Search

Acute toxicity experiments with purified toxins show that four species of zooplankton differ markedly in their physiological sensitivity to cyclic peptide hepatotoxins from Microcystis ueru- ginosu (microcystin-LR1 and Noduluria spumigenu (nodularin). The copepod Diaptomus birgei was most sensitive (48-h LC,, for microcystin-LR ranged from 0.45 to 1.00 pg ml-l), Daphnia pulicuriu was least sensitive (48-h LCsO, 21.4 pg ml-l), and

WILLIAM R. DEMOTT; QING-XUE ZHANG; WAYNE W. CARMICHAEL

1991-01-01

205

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

Microsoft Academic Search

Two new species of parasitic copepods, one from each of the families Hatschekiidae and Bomolochidae, are reported from two\\u000a immigrant species of rabbitfishes (Family Siganidae), both of which originated from the Red Sea but are now established in\\u000a the Mediterranean. The descriptions of Hatschekia\\u000a siganicola n. sp. and Nothobomolochus neomediterraneus n. sp. are based on material of both sexes obtained

H. H. El-Rashidy; G. A. Boxshall

2011-01-01

206

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

PubMed

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

El-Rashidy, H H; Boxshall, G A

2011-07-01

207

Assessment of the roles of copepod Apocyclops royi and bivalve mollusk Meretrix lusoria in white spot syndrome virus transmission.  

PubMed

Here, we investigate the roles of copepods and bivalve mollusks in the transmission of white spot syndrome virus (WSSV), which is the causative pathogen of an acute, contagious disease that causes severe mortalities in cultured shrimp. Copepods are common components in seawater ponds and are often eaten as live food by shrimp post-larvae. WSSV has been detected in these animals, but it is unknown whether this was due to contamination or infection. Meanwhile, the bivalve mollusk Meretrix lusoria is often used as live food for brooders, and in Taiwan, this hard clam is sometimes co-cultured with shrimp in farming ponds. However, mollusks' ability to accumulate, or allow the replication of, shrimp viruses has not previously been studied. In this study, WSSV, the copepod Apocyclops royi and bivalve mollusk M. lusoria were experimentally challenged with WSSV and then assayed for both the presence of the virus and for viral gene expression. Results showed that the WSSV genome could be detected and that the viral loads were increased in a time-dependent manner after challenge both in A. royi and M. lusoria. Reverse transcriptase PCR monitoring of WSSV gene expression showed that WSSV could replicate in A. royi but not in M. lusoria, which suggested that WSSV, while could infect A. royi, was only accumulated in M. lusoria. A bioassay further showed that the WSSV accumulated in M. lusoria could be transmitted to Litopenaeus vannamei and cause severe infection. PMID:21279409

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

2011-10-01

208

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

209

Infection dynamics of Marteilia refringens in flat oyster Ostrea edulis and copepod Paracartia grani in a claire pond of Marennes-Oléron Bay.  

PubMed

The protozoan parasite Marteilia refringens has been partly responsible for the severe decrease in the production of the European flat oyster Ostrea edulis Linnaeus in France since the 1970s. The calanoid copepod Paracartia grani Sars was recently found to be a host for M. refringens in French shallow-water oyster ponds ('claires'). This study reconsidered M. refringens transmission dynamics in the light of this finding, taking into account not only oyster infection dynamics and environmental factors but also data concerning the copepod host. P. grani population dynamics in the claire under study revealed that this species is the dominant planktonic copepod in this confined ecosystem. During winter, M. refringens overwintered in O. edulis, with P. grani existing only as resting eggs in the sediment. The increase in temperature in spring controlled and synchronized both the release of M. refringens sporangia in the oyster feces, and the hatching of the benthic resting eggs of the copepod. Infection of oysters by M. refringens was limited to June, July and August, coinciding with (1) the highest temperature recorded in the claire, and (2) the highest abundance of P. grani. PCR detection of M. refringens in P. grani during the summer period was linked to the release of parasite sporangia by the oyster. Our results are supported by previous results on the effective transmission of this parasite from the oyster to the copepod. PMID:15584417

Audemard, Corinne; Sajus, Marie-Céline; Barnaud, Antoine; Sautour, Benoit; Sauriau, Pierre-Guy; Berthe, Frank J C

2004-10-21

210

Bioaccumulation of 14C-PCB 101 and 14C-PBDE 99 in the marine planktonic copepod Calanus finmarchicus under different food regimes.  

PubMed

Bioaccumulation factors (BAFs) were determined for (14)C-PCB 101 and (14)C-PBDE 99 in the pelagic copepod Calanus finmarchicus after exposure to either contaminated water or after being fed contaminated phytoplankton (the dinoflagellate Prorocentrum minimum or the diatom Thalassiosira weissflogii). BAFs in algae range from 7.6 to 8.0 for PCB 101 and from 8.5 to 8.6 for PBDE 99. BAFs in copepods were significantly lower, 6.3-6.8 for PCB 101 and 7.6 for PBDE 99. For each compound, the BAFs in copepods were independent of what algal species they had consumed, even though the bioaccumulation of both compounds were higher in P. minimum than in T. weissflogii. The ratios between BAF and the K(ow) for PCB 101 and PBDE 99 were similar within each of the three species, but varied between species. For copepods the ratios were 2-4, for T. weissfloggii 15-22 and for P. minimum 32-40. The data strongly suggest that the two compounds bioaccumulate in a similar manner and that there is no biomagnification in the transfer between phytoplankton and herbivorous copepods. PMID:16949662

Magnusson, K; Magnusson, M; Ostberg, P; Granberg, M; Tiselius, P

2007-02-01

211

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

PubMed

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

Avdeev, G V; Sirenko, B I

2005-01-01

212

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

PubMed

Substantial variations are reported for egg production and hatching rates of copepods exposed to elevated carbon dioxide concentrations (pCO2). One possible explanation, as found in other marine taxa, is that prior parental exposure to elevated pCO2 (and/or decreased pH) affects reproductive performance. Previous studies have adopted two distinct approaches, either (1) expose male and female copepoda to the test pCO2/pH scenarios, or (2) solely expose egg-laying females to the tests. Although the former approach is more realistic, the majority of studies have used the latter approach. Here, we investigated the variation in egg production and hatching success of Acartia tonsa between these two experimental designs, across five different pCO2 concentrations (385-6000 µatm pCO2). In addition, to determine the effect of pCO2 on the hatching success with no prior parental exposure, eggs produced and fertilized under ambient conditions were also exposed to these pCO2 scenarios. Significant variations were found between experimental designs, with approach (1) resulting in higher impacts; here >20% difference was seen in hatching success between experiments at 1000 µatm pCO2 scenarios (2100 year scenario), and >85% at 6000 µatm pCO2. This study highlights the potential to misrepresent the reproductive response of a species to elevated pCO2 dependent on parental exposure. PMID:25221371

Cripps, Gemma; Lindeque, Penelope; Flynn, Kevin

2014-09-01

213

Acclimation and adaptation to common marine pollutants in the copepod Tigriopus californicus.  

PubMed

Establishing water quality criteria using bioassays is complicated by variation in chemical tolerance between populations. Two major contributors to this variation are acclimation and adaptation, which are both linked to exposure history, but differ in how long their effects are maintained. Our study examines how tolerance changes over multiple generations of exposure to two common marine pollutants, copper (Cu) and tributyltin oxide (TBTO), in a sexually reproducing marine copepod, Tigriopus californicus. Lines of T. californicus were chronically exposed to sub-lethal levels of Cu and TBTO for 12 generations followed by a recovery period of 3 generations in seawater control conditions. At each generation, the average number of offspring produced and survived to 28 d was determined and used as the metric of tolerance. Lines exposed to Cu and TBTO showed an overall increase in tolerance over time. Increased Cu tolerance arose by generation 3 in the chronically exposed lines and was lost after 3 generations in seawater control conditions. Increased TBTO tolerance was detected at generation 7 and was maintained even after 3 generations in seawater control conditions. It was concluded from this study that tolerance to Cu is consistent with acclimation, a quick gain and loss of tolerance. In contrast, TBTO tolerance is consistent with adaptation, in which onset of tolerance was delayed relative to an acclimation response and maintained in the absence of exposure. These findings illustrate that consideration of exposure history is necessary when using bioassays to measure chemical tolerance. PMID:25048941

Sun, Patrick Y; Foley, Helen B; Handschumacher, Lisa; Suzuki, Amanda; Karamanukyan, Tigran; Edmands, Suzanne

2014-10-01

214

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

PubMed

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

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

2014-09-01

215

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

PubMed Central

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

Barreto, Felipe S.; Burton, Ronald S.

2013-01-01

216

A review of the biology of the parasitic copepod Lernaeocera branchialis (L., 1767) (Copepoda: Pennellidae).  

PubMed

This review concerns the parasitic marine copepod Lernaeocera branchialis (L., 1767) and provides an overview of current knowledge concerning its biology and host-parasite interactions. The large size and distinctive appearance of the metamorphosed adult female stage, coupled with the wide exploitation and commercial importance of its final gadoid hosts, means that this species has long been recognised in the scientific literature. The fact that the Atlantic cod, Gadus morhua L., is one of its key host species, and has itself had a major impact on the social and economic development of many countries bordering the North Atlantic for more than 10 centuries is also a factor in its widespread recognition. L. branchialis is recognised as a pathogen that could have major effects on the aquaculture industry and with gadoid (especially cod) farming expanding in several North Atlantic countries, there is considerable potential for this parasite to become a serious problem for commercial mariculture. The main subject areas covered are the parasite's taxonomy; the life history of the parasite including its life cycle, reproduction and host associations; parasite physiology; parasite seasonality and distribution; and the pathogenic effects of the parasite on its host. PMID:18063099

Brooker, Adam J; Shinn, Andrew P; Bron, James E

2007-01-01

217

Very Bright Green Fluorescent Proteins from the Pontellid Copepod Pontella mimocerami  

PubMed Central

Background Fluorescent proteins (FP) homologous to the green fluorescent protein (GFP) from the jellyfish Aequorea victoria have revolutionized biomedical research due to their usefulness as genetically encoded fluorescent labels. Fluorescent proteins from copepods are particularly promising due to their high brightness and rapid fluorescence development. Results Here we report two novel FPs from Pontella mimocerami (Copepoda, Calanoida, Pontellidae), which were identified via fluorescence screening of a bacterial cDNA expression library prepared from the whole-body total RNA of the animal. The proteins are very similar in sequence and spectroscopic properties. They possess high molar extinction coefficients (79,000 M?1 cm?) and quantum yields (0.92), which make them more than two-fold brighter than the most common FP marker, EGFP. Both proteins form oligomers, which we were able to counteract to some extent by mutagenesis of the N-terminal region; however, this particular modification resulted in substantial drop in brightness. Conclusions The spectroscopic characteristics of the two P. mimocerami proteins place them among the brightest green FPs ever described. These proteins may therefore become valuable additions to the in vivo imaging toolkit. PMID:20644720

Hunt, Marguerite E.; Scherrer, Michael P.; Ferrari, Frank D.; Matz, Mikhail V.

2010-01-01

218

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

PubMed

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

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

2013-02-01

219

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

PubMed Central

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

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

2012-01-01

220

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

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

221

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

PubMed

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

Pohnert, Georg

2005-06-01

222

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

PubMed Central

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

Kiørboe, Thomas; Jiang, Houshuo

2013-01-01

223

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

PubMed

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

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

2013-03-01

224

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

225

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

NASA Astrophysics Data System (ADS)

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

Liu, Guangxing; Xu, Donghui

2009-12-01

226

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

PubMed

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

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

2015-01-01

227

Functional characterization of P-glycoprotein in the intertidal copepod Tigriopus japonicus and its potential role in remediating metal pollution.  

PubMed

The intertidal copepod Tigriopus japonicus has been widely used in aquatic toxicity testing for diverse environmental pollutants including metals. Despite relatively well-characterized in vivo physiological modulations in response to aquatic pollutants, the molecular mechanisms due to toxicity and detoxification are still unclear. To better understand the mechanisms of metal transport and further detoxification, T. japonicus P-glycoprotein (TJ-P-gp) with conserved motifs/domains was cloned and measured for protein activity against the transcript and protein expression profiles in response to metal exposure. Specifically, we characterized the preliminary efflux activity and membrane topology of TJ-P-gp protein that supports a transport function for chemicals. To uncover whether the efflux activity of TJ-P-gp protein would be modulated by metal treatment, copepods were exposed to three metals (Cd, Cu, and Zn), and were observed for both dose- and time-dependency on the efflux activity of TJ-P-gp protein with or without 10?M of P-gp-specific inhibitors verapamil and zosuquidar (LY335979) for 24h over a wide range of metal concentrations. In particular, treatment with zosuquidar induced metal accumulation in the inner body of T. japonicus. In addition, three metals significantly induced the transporting activity of TJ-P-gp in a concentration-dependent manner in both transcript and protein levels within 24h. Together these data indicate that T. japonicus has a conserved P-gp-mediated metal defense system through the induction of transcriptional up-regulation of TJ-P-gp gene and TJ-P-gp protein activity. This finding provides further understanding of the molecular defense mechanisms involved in P-glycoprotein-mediated metal detoxification in copepods. PMID:25198425

Jeong, Chang-Bum; Kim, Bo-Mi; Kim, Rae-Kwon; Park, Heum Gi; Lee, Su-Jae; Shin, Kyung-Hoon; Leung, Kenneth Mei Yee; Rhee, Jae-Sung; Lee, Jae-Seong

2014-11-01

228

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

PubMed

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

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

2014-10-01

229

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

NASA Astrophysics Data System (ADS)

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

Wang, Lu; Xu, Kuidong

2013-11-01

230

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

PubMed Central

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

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

2013-01-01

231

Microbial colonization of copepod body surfaces and chitin degradation in the sea  

NASA Astrophysics Data System (ADS)

Next to cellulose, chitin (composed of N-acetyl-D-glucosamine sugar units) is the most frequently occurring biopolymer in nature. Among the most common sources of chitin in the marine environment are copepods and the casings of their fecal pellets. During the mineralization of chitin by microorganisms, which occurs chiefly by means of exoenzymes, nitrogen and carbon are returned to the nutrient cycle. In this study, the microbial colonization of the moults (exuviae), carcasses and fecal pellets of Tisbe holothuriae Humes (Copepoda: Harpacticoida) was examined in the laboratory. Results obtained with DAPI staining indicated that a succession of microorganisms from rodshaped bacteria and cocci to starlike aggregates took place, followed by the yeastlike fungus Aureobasidium pullulans (de Bary) Arnaud. No differences were noted between moults from various developmental stages, from nauplius to adult. The ventral sides and extremities of exuviae and carcasses were more rapidly colonized than other parts of the bodies. The casings of fecal pellets were frequently surrounded by bacteria with fimbriae or slime threads. In situ studies of chitin degradation (practical grade chitin from crustacean shells) with the mesh bag technique showed that about 90% of the original substance was lost after 3 months exposure in seawater at temperatures between 10 and 18°C. Chitinase activity was measured in the water at two stations near Helgoland, an island in the North Sea. A higher exoenzymatic activity was found in the rocky intertidal zone, compared to the Station Cable Buoy located between the main and Düne island. These values correspond to the higher bacteria numbers (cfu ml-1) found in the rocky intertidal: 10 to 100× greater than those found at the Cable Buoy Station.

Kirchner, M.

1995-03-01

232

Egg production in three species of Antarctic Calanoid Copepods during an austral summer  

NASA Astrophysics Data System (ADS)

Egg production in three species of calanoid copepods Rhincalanus gigas, Calanoides acutus and Calanus simillimus was investigated via incubations of females and recovery of eggs from net hauls made around South Georgia during January 1993. Average daily egg production was highest for the sub-Antarctic C. simillimus, (15.5 eggs female -1 d -1). This species normally spawns in the spring in the central part of its geographical range but was apparently delayed by the colder waters found around South Georgia. For R. gigas and C. acutus egg production averaged 8.9 and 6.0 eggs female -1 d -1, respectively. The former species appeared to be undergoing protracted recruitment while the population of the latter was preparing to overwinter. Considerable interstation variability existed, although no relationships were apparent between surface chlorophyll concentrations and either egg production in experiments or in the numbers of eggs recovered by the nets. Clutch size (eggs produced spawning female -1 d -1) did not differ significantly between the three species although the maximum clutch size recorded for R. gigas (94 eggs) was almost twice that of C. simillimus. Samples taken from the Bellingshausen Sea during the latter part of 1992 indicated that recruitment of R. gigas and C. acutus commenced in early December in this region when adult females were concentrated in the surface 250 m and a diatom bloom was developing. Egg numbers were highest in the surface 50 m (up to 350 m --3) at both the Bellingshausen and South Georgia stations. At the latter site females migrated into these surface layers at night; thus it would appear that spawning is largely nocturnal and linked to diurnal migratory behaviour.

Ward, Peter; Shreeve, Rachael S.

1995-05-01

233

Alien parasitic copepods in mussels and oysters of the Wadden Sea  

NASA Astrophysics Data System (ADS)

Molluscan intestinal parasites of the genus Mytilicola, specifically M. intestinalis, were initially introduced into bivalves in the North Sea in the 1930s. It was presumably introduced from the Mediterranean with ship-fouling mussels, then attained epidemic proportions in Mytilus edulis in the 1950s and is now widely established in the North Sea region. Mytilicola orientalis was co-introduced with Pacific oysters to France in the 1970s and in the southern North Sea in the early 1990s. Its main host Crassostrea gigas has massively invaded the Wadden Sea with a concomitant decline in mussels. To explore whether introduced mytilicolid parasites could play a role in the shifting dominance from native mussels to invasive oysters, we analysed 390 mussels and 174 oysters collected around the island of Sylt in the northern Wadden Sea. We show that M. intestinalis has a prevalence >90% and a mean intensity of 4 adult copepods in individual mussels with >50 mm shell length at all sheltered sites. By contrast, none were found in the oysters. However, at one site, we found M. orientalis in C. gigas with a prevalence of 10% and an intensity of 2 per host individual (August 2008). This constitutes the most northern record in Europe for this Pacific parasite until now. Alignments of partial sequences of the mitochondrial cytochrome oxidase I (COI) gene and the nuclear internal transcribed spacers (ITS) and 18S rDNA sequences each show a distinct difference between the two species, which confirms our morphological identification. We suggest that the high parasite load in mussels compared to oysters may benefit the continued expansion of C. gigas in the Wadden Sea.

Elsner, Nikolaus O.; Jacobsen, Sabine; Thieltges, David W.; Reise, Karsten

2011-09-01

234

Factors influencing the distribution and abundance of diaptomid copepods in high elevation lakes in the Pacific Northwest, USA  

USGS Publications Warehouse

We investigated the impact of abiotic factors and trout density on distribution and abundance of diaptomid copepods in high-elevation lakes in North Cascades National Park Service Complex (NOCA), Washington, USA. The most common large diaptomid, D. kenai (mean length = 1.88 mm), was able to persist over a wide range of abiotic factors, but the small herbivorous diaptomid, D. tyrrelli (mean length = 1.18 mm), was restricted to shallow lakes (maximum depth 250 fish ha-1) than in fishless lakes, in deep lakes with reproducing trout, or in lakes where trout do not reproduce and are 0periodically stocked with fry at low densities (average 179 fry a-1). In lakes where chemical conditions were suitable for D. tyrrelli, the small diaptomid was often abundant when trout density was high and large diaptomids were either absent or in low abundance. Our research suggests that trout density, nutrient concentration, and lake depth influence the abundance of diaptomid copepods in high lakes in NOCA.

Liss, W.J.; Larson, Gary L.; Deimling, E.; Ganio, L.; Hoffman, Robert L.; Lomnicky, G.A.

1998-01-01

235

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

NASA Astrophysics Data System (ADS)

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

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

2007-10-01

236

Dietary Carotenoids Regulate Astaxanthin Content of Copepods and Modulate Their Susceptibility to UV Light and Copper Toxicity  

PubMed Central

High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal). Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC50 values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers. PMID:22822352

Caramujo, Maria-José; de Carvalho, Carla C. C. R.; Silva, Soraya J.; Carman, Kevin R.

2012-01-01

237

RNA:DNA ratios of Baltic Sea herring larvae and copepods in embayment and open sea habitats  

NASA Astrophysics Data System (ADS)

Elucidation of important nursery habitats for young fish can aid in the management and assessment of fish stocks. Herring ( Clupea harengus) in the Baltic Sea primarily spawn in coastal areas, but larvae are also present in off-shore, open sea areas. To investigate if sheltered coastal habitats provide a better growth environment for larval herring, we compared short-term growth (as indexed by whole body RNA:DNA ratios) of larval herring from three habitat types of the northwest Baltic proper (sheltered inner bay, exposed outer bay, and open sea). In addition, we compared individual RNA content of adult female Eurytemora affinis (a common Baltic copepod) among these different habitats. High RNA levels in these copepods indicate high production of nauplii, which are important food for larval herring. Both RNA:DNA ratios of larval herring and RNA content of E. affinis were significantly greater in embayment habitats, suggesting that the sheltered coastal areas are high quality nursery habitats for young Baltic herring.

Höök, Tomas O.; Gorokhova, Elena; Hansson, Sture

2008-01-01

238

Photoenhanced toxicity of weathered Alaska North Slope crude oil to the calanoid copepods Calanus marshallae and Metridia okhotensis.  

PubMed

This study investigated the synergistic toxicity of aqueous polyaromatic compounds (PAC) dissolved from crude oil and ultraviolet radiation (UV) in natural sunlight to the calanoid copepods Calanus marshallae and Metridia okhotensis. These copepods were first exposed to low doses (approximately 2 microg of total PAC/L) of the water-soluble fraction of weathered Alaska North Slope crude oil for 24 h and subsequently to low or high levels of natural sunlight. Responses included mortality, impairment of swimming ability, and discoloration of lipid sacs. There was 80-100% mortality and morbidity of C. marshallae exposed to UV and oil as compared to less than 10% effect in oil-only or UV-only treatments. In M. okhotensis, 100% mortality occurred in the UV and oil treatment, 43% mortality and 27% morbidity in the UV-only treatment, and less than 5% effect in the oil-only treatment. Bioaccumulation factors were approximately 8000 for C. marshallae and approximately 2000 for M. okhotensis. The interaction of the effect of PAC and UV radiation was highly significant (P < 0.005) in both experiments. PMID:12269748

Duesterloh, Switgard; Short, Jeffrey W; Barron, Mace G

2002-09-15

239

Acute and chronic toxicity study of the water accommodated fraction (WAF), chemically enhanced WAF (CEWAF) of crude oil and dispersant in the rock pool copepod Tigriopus japonicus.  

PubMed

We determined the toxicity of the water accommodated hydrocarbon fraction (WAF), two chemically enhanced WAFs (CEWAFs; CEWAF-C, Crude oil+Corexit 9500 and CEWAF-H, Crude oil+Hiclean) of crude oil and two dispersants (Corexit 9500 and Hiclean) to the rock pool copepod Tigriopus japonicus. In the acute toxicity test, Corexit 9500 was the most toxic of all the chemicals studied. The nauplius stage of T. japonicus was more susceptible to the toxic chemicals studied than the adult female. The toxicity data using the nauplius stage was then considered as baseline to determine the spiking concentration of chemicals for chronic toxicity tests on the copepod. As the endpoints in the chronic toxicity test, survival, sex ratio, developmental time and fecundity of the copepod were used. All chemicals used in this study resulted in increased toxicity in the F1 generation. The lowest-observed-adverse-effect (LOAE) concentrations of WAF, CEWAF-H, CEWAF-C, Hiclean and Corexit 9500 were observed to be 50%, 10%, 0.1%, 1% and 1%, respectively. The results in present study imply that copepods in marine may be negatively influenced by spilled oil and dispersant. PMID:23466279

Lee, Kyun-Woo; Shim, Won Joon; Yim, Un Hyuk; Kang, Jung-Hoon

2013-08-01

240

The effects of Orimulsion and Fuel Oil #6 on the hatching success of copepod resting eggs in the seabed of Tampa Bay, Florida  

Microsoft Academic Search

A 3-month microcosm study was conducted to observe the potential effects of two fuels, Orimulsion and Fuel Oil #6, on the hatching success of copepod resting eggs in the seabed of Tampa Bay, Florida. Microcosms were dosed with one of five hydrocarbon treatments via hydrocarbon-coated sand and compared with controls. Acartia tonsa eggs were nonviable in all treatments after only

Barbara L. Suderman; Nancy H. Marcus

2002-01-01

241

Effect of UVB radiation on the survival, feeding, and egg production of the brackish-water copepod, Sinocalanus tenellus, with notes on photoreactivation  

Microsoft Academic Search

We examined the effects of UVB radiation on hatching success of eggs, survival of various naupliar and copepodite stages, and feeding and egg production of adult females of the brackish-water copepod, Sinocalanus tenellus, by exposure to varying doses of UVB irradiance in the laboratory. Artificial UVB radiation resulted in an increased mortality of eggs, nauplii and copepodites with increasing UVB

Dorothy G. Lacuna; Shin-ichi Uye

2000-01-01

242

ACUTE TOXICITY OF FIVE SEDIMENT-ASSOCIATED METALS, INDIVIDUALLY AND IN A MIXTURE, TO THE ESTUARINE MEIOBENTHIC HARPACTICOID COPEPOD AMPHIASCUS TENUIREMIS. (R825279)  

EPA Science Inventory

Abstract The acute effects of many individual, seawater-solubilized metals on meiobenthic copepods and nematodes are well known. In sediments, however, metals most often occur as mixtures, and it is not known whether such mixtures exhibit simple additive toxicity to me...

243

No evidence for induction or selection of mutant sodium channel expression in the copepod Acartia husdsonica challenged with the toxic dinoflagellate Alexandrium fundyense  

PubMed Central

Some species in the dinoflagellate genus Alexandrium spp. produce a suite of neurotoxins that block sodium channels, known as paralytic shellfish toxins (PST), which have deleterious effects on grazers. Populations of the ubiquitous copepod grazer Acartia hudsonica that have co-occurred with toxic Alexandrium spp. are better adapted than naïve populations. The mechanism of adaptation is currently unknown. We hypothesized that a mutation in the sodium channel could account for the grazer adaptation. We tested two hypotheses: (1) Expression of the mutant sodium channel could be induced by exposure to toxic Alexandrium fundyense; (2) in the absence of induction, selection exerted by toxic A. fundyense would favor copepods that predominantly express the mutant isoform. In the copepod A. hudsonica, both isoforms are expressed in all individuals in varying proportions. Thus, in addition to comparing expression ratios of wild-type to mutant isoforms for individual copepods, we also partitioned copepods into three groups: those that predominantly express the mutant (PMI) isoform, the wild-type (PWI) isoform, or both isoforms approximately equally (EI). There were no differences in isoform expression between individuals that were fed toxic and nontoxic food after three and 6 days; induction of mutant isoform expression did not occur. Furthermore, the hypothesis that mutant isoform expression responds to toxic food was also rejected. That is, no consistent evidence showed that the wild-type to mutant isoform ratios decreased, or that the relative proportion of PMI individuals increased, due to the consumption of toxic food over four generations. However, in the selected line that was continuously exposed to toxic food sources, egg production rate increased, which suggested that adaptation occurred but was unrelated to sodium channel isoform expression. PMID:25535562

Finiguerra, Michael; Avery, David E; Dam, Hans G

2014-01-01

244

No evidence for induction or selection of mutant sodium channel expression in the copepod Acartia husdsonica challenged with the toxic dinoflagellate Alexandrium fundyense.  

PubMed

Some species in the dinoflagellate genus Alexandrium spp. produce a suite of neurotoxins that block sodium channels, known as paralytic shellfish toxins (PST), which have deleterious effects on grazers. Populations of the ubiquitous copepod grazer Acartia hudsonica that have co-occurred with toxic Alexandrium spp. are better adapted than naïve populations. The mechanism of adaptation is currently unknown. We hypothesized that a mutation in the sodium channel could account for the grazer adaptation. We tested two hypotheses: (1) Expression of the mutant sodium channel could be induced by exposure to toxic Alexandrium fundyense; (2) in the absence of induction, selection exerted by toxic A. fundyense would favor copepods that predominantly express the mutant isoform. In the copepod A. hudsonica, both isoforms are expressed in all individuals in varying proportions. Thus, in addition to comparing expression ratios of wild-type to mutant isoforms for individual copepods, we also partitioned copepods into three groups: those that predominantly express the mutant (PMI) isoform, the wild-type (PWI) isoform, or both isoforms approximately equally (EI). There were no differences in isoform expression between individuals that were fed toxic and nontoxic food after three and 6 days; induction of mutant isoform expression did not occur. Furthermore, the hypothesis that mutant isoform expression responds to toxic food was also rejected. That is, no consistent evidence showed that the wild-type to mutant isoform ratios decreased, or that the relative proportion of PMI individuals increased, due to the consumption of toxic food over four generations. However, in the selected line that was continuously exposed to toxic food sources, egg production rate increased, which suggested that adaptation occurred but was unrelated to sodium channel isoform expression. PMID:25535562

Finiguerra, Michael; Avery, David E; Dam, Hans G

2014-09-01

245

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

246

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

247

Toxicity effect of Delonix elata (Yellow Gulmohr) and predatory efficiency of Copepod, Mesocyclops aspericornis for the control of dengue vector, Aedes aegypti  

PubMed Central

Objective To evaluate the toxicity, predatory efficiency of Delonix elata (D. elata) and Mesocyclops aspericornis (M. aspericornis) against dengue vector, Aedes aegypti (Ae. aegypti). Methods A mosquitocidal bioassay was conducted at different concentration of plant extract followed by WHO standard method. The probit analysis of each tested concentration and control were observed by using software SPSS 11 version package. The each tested concentration variable was assessed by DMRT method. The predatory efficiency of copepod was followed by Deo et al., 1988. The predator, M. aspericornis was observed for mortality, abnormalities, survival and swimming activity after 24 h treatment of plant and also predation on the mosquito larvae were observed. Results D. elata were tested for biological activity against the larvae, and pupae of Ae. aegypti. Significant mortality effects were observed in each life stage. The percentage of mortality was 100% in first and second instars whereas 96%, 92% in third and fourth instars. Fitted probit-mortality curves for larvae indicated the median and 90% lethal concentrations of D. elata for instars 1-4 to be 4.91 (8.13), 5.16 (8.44), 5.95 (7.76) and 6.87 (11.23), respectively. The results indicate that leaf extract exhibits significant biological activity against life stages. The present study revealed that D. elata is potentially important in the control of Ae. aegypti. Similar studies were conducted for predatory efficiency of Copepod, M. aspericornis against mosquito vector Ae. Aegypti. This study reported that the predatory copepod fed on 39% and 25% in I and III instar larvae of mosquito and in combined treatment of D. elata and copepod maximum control of mosquito larval states and at 83%, 80%, 75% and 53% in I, II, III and IV instars, respectively. Conclusions The combined action of plant extract and predatory copepod to effectively control mosquito population and reduce the dengue transmitting diseases.

Vasugi, Chellamuthu; Kamalakannan, Siva; Murugan, Kadarkarai

2013-01-01

248

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

PubMed Central

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

2011-01-01

249

Diel changes in vertical distribution and feeding activity of copepods in ice-covered Resolute Passage, Canadian Arctic, in spring 1992  

NASA Astrophysics Data System (ADS)

To examine the role of copepods in the marine ecosystem under sea ice, diel changes in their vertical distribution and feeding activity were observed in May 1992 in Resolute Passage, Canadian Arctic. Copepods were numerically abundant, making up 98% of the zooplankton assemblage. Pseudocalanus was the dominant copepod, accounting for 92% of the copepods in number. All stages, particularly copepodid stages IV and V of Pseudocalanus, showed upward migration at night, concentrating just below the ice between 2000 and 2300 h and descending into the deeper water around midnight. Gut pigment content of Pseudocalanus just below the ice showed diel changes, with higher values in the day than at night. Gut evacuation rates were independent of the initial gut pigment contents. The ingestion rate of the Pseudocalanus population was high at 2000 h in the top 0-1 m layer under the ice, reaching more than 20 ?g pig m -3 h -1. In the layers deeper than 3 m, the ingestion rates of the population was relatively high around 1800-8000 h and 0600 h, with a maximum of nearly 0.5 ?g pig.m -3 h -1. These higher ingestion rates did not extend throughout the night in the whole water column. Cumulative daily ingestion rates for the population in the top 0-3 m and the whole water column were calculated to be 0.30 and 2.57 mg pig.m -2 d -1, respectively. Similarly, consumption of the daily ice algal production was estimated to be 4.2% in the upper water column and 36.8% for the total water column. Scanning electron microscopic observations of in situ gut contents revealed that ice algal diatoms were not the nutritive sources for Pseudocalanus. We suggest that naked autotrophs could be an important food source for copepods under the ice in Resolute Passage in the spring.

Hattori, Hiroshi; Saito, Hiroaki

1997-02-01

250

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

PubMed

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

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

2013-08-30

251

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

PubMed

Irgarol 1051 has been widely used as a booster biocide in combination with copper (Cu) in antifouling paints. The combined toxicity of Irgarol with Cu on marine organisms, however, has not been fully investigated. This study investigated the acute and chronic toxicities of binary mixtures of Irgarol and CuSO(4) to the marine copepod Tigriopus japonicus. The acute combined toxicity of Irgarol and Cu was simple additive as revealed by two response surface models and their contours. However, based on chronic full life-cycle tests, when Irgarol was combined with Cu at an environmentally realistic concentration (10 ?g L(-1)), a slightly synergistic effect was observed at a high Irgarol concentration (940 ?g L(-1)), as shown by a significant increase in larval mortality. As Cu contamination is widespread in coastal environments, our results entail the importance of considering the combined toxic effect of the booster biocide and Cu for setting ecologically realistic water quality criteria. PMID:23069205

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

2013-01-01

252

Effects of UV radiation on hatching, lipid peroxidation, and fatty acid composition in the copepod Paracyclopina nana.  

PubMed

To evaluate the effects of UV radiation on the reproductive physiology and macromolecules in marine zooplankton, several doses of UV radiation were used to treat the copepod Paracyclopina nana, and we analyzed in vivo endpoints of their life cycle such as mortality and reproductive parameters with in vitro biochemical biomarkers such as reactive oxygen species (ROS), the modulated enzyme activity of glutathione S-transferase (GST) and superoxide dismutase (SOD), and the production of a byproduct of peroxidation (e.g. malonedialdehyde, MDA). After UV radiation, the survival rate of P. nana was significantly reduced. Also, egg sac damage and a reduction in the hatching rate of offspring were observed in UV-irradiated ovigerous females. According to the assessed biochemical parameters, we found dose-dependent increases in ROS levels and high levels of the lipid peroxidation decomposition product by 2 kJ m(-2), implying that P. nana was under off-balanced status by oxidative stress-mediated cellular damage. Antioxidant enzyme activities of GST and SOD increased over different doses of UV radiation. To measure UV-induced lipid peroxidation, we found a slight reduction in the composition of essential fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These findings indicate that UV radiation can induce oxidative stress-triggered lipid peroxidation with modulation of antioxidant enzyme activity, leading to a significant effect on mortality and reproductive physiology (e.g. fecundity). These results demonstrate the involvement of UV radiation on essential fatty acids and its susceptibility to UV radiation in the copepod P. nana compared to other species. PMID:24952335

Won, Eun-Ji; Lee, Yeonjung; Han, Jeonghoon; Hwang, Un-Ki; Shin, Kyung-Hoon; Park, Heum Gi; Lee, Jae-Seong

2014-09-01

253

Life-table evaluation of sediment-associated chlorpyrifos chronic toxicity to the benthic copepod, Amphiascus tenuiremis.  

PubMed

A partial life-cycle experiment was conducted to assess chronic effects of sediment-associated chlorpyrifos, an organophosphate pesticide, on a marine, benthic copepod population. The static-renewal experiment was initiated with 4 treatments including control, 13 replicates per treatment with one female (bearing first clutch of eggs) per replicate. No males were added because one fertilization is sufficient for several clutches. Once weekly, all replicate chamber contents (10-ml culture tubes with 1.5 ml of sediment and 5 ml of seawater) were sieved and enumerated to determine survival and fecundity. Surviving adult females were placed back into chambers with newly spiked sediments. This process was repeated for 7 weeks until all initial females were dead or reproduction had ceased for at least two weeks. Survival and fecundity data were then used to determine population dynamic parameters such as r (intrinsic rate of natural increase) for each treatment. Results revealed a chronic toxicity response with significant population effects (p<0.05) in all pesticide treatments versus the control; concentrations that represent 7-32% of the 96-hr LC50. The control treatment had an r value 26-52% higher than the pesticide treatments. This translated into a control population rate increase of up to twice that of pesticide treatments. In addition, significant reductions in weekly and total fecundity were found in all chlorpyrifos treatments. Based on these results, usage of population parameters with benthic copepods allows for an integrative measurement of population effects from chronic exposure to sediment-associated contaminants. PMID:8687993

Green, A S; Chandler, G T

1996-07-01

254

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

PubMed Central

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

2013-01-01

255

Research On Zooplankton in the Gulf of Rapallo  

Microsoft Academic Search

Zooplankton samples, collected in autumn 1996 from two stations in the Gulf of Rapallo, Ligurian Sea (Rapallo Harbour and Prelo Bay, which is a more open site with lower human impacts) were analysed. at both stations, the community was dominated by copepods (mainly juveniles and adults of different species of Acartia and Oithona) and meroplankton (mainly polychaete larvae). Total zooplankton

S. Sei; P. Licandro; Zunini Sertorio; I. Ferrari

1999-01-01

256

Zooplankton swarms: characteristics, proximal cues and proposed advantages  

Microsoft Academic Search

This review focuses on monospecific swarms of four taxonomic groups of small crustaceans: three groups are marine copepods: oithonids (Oithona and Dioithona), Acartia species and Calanus species; and the fourth group includes freshwater cladoceran species in the Order Anomopoda. For each of these groups there is a substantial literature on swarming behavior from field studies and laboratory experiments. Swarming characteristics

Julie W. Ambler

2002-01-01

257

Toxicity of blooms of the cyanobacterium Trichodesmium to zooplankton  

Microsoft Academic Search

The marine filamentous bloom-forming cyanobacteria Trichodesmium thiebautii and T. erythraeum were collected at locations in the Carribean during Jan.–Feb. 1991. They were screened for toxicity using Artemia salina and several species of copepods, which were harpacticoid grazers, filter-feeding calanoids, or cyclopoid copepods. Approximately\\u000a 50% of the 89 T. thiebautii samples caused> 50% lethality of A. salina, though none of the

S. P. Hawser; J. M. O'Neil; M. R. Roman; G. A. Coddl

1992-01-01

258

The effects of temperature and salinity on reproductive success of Temora longicornis in the Baltic Sea: a copepod coping with a tough situation  

Microsoft Academic Search

At specific locations within the Baltic Sea, thermoclines and haloclines can create rapid spatial and temporal changes in\\u000a temperature (T) and salinity (S) exceeding 10°C and 9 psu with seasonal ranges in temperature exceeding 20°C. These wide ranges in abiotic factors affect\\u000a the distribution and abundance of Baltic Sea copepods via species-specific, physiological-based impacts on vital rates. In\\u000a this laboratory study,

Linda Holste; Michael A. St. John; Myron A. Peck

2009-01-01

259

Determining Demographic Effects of Cypermethrin in the Marine Copepod Acartia tonsa : Stage-Specific Short Tests Versus Life-Table Tests  

Microsoft Academic Search

Short-term lethal and sublethal responses of the calanoid copepod Acartia tonsa to cypermethrin were compared with life-table responses to assess whether or not it is necessary to use exposure periods\\u000a longer than 5 days to estimate demographic responses to stress. More specifically, by limiting exposure periods to sensitive\\u000a age classes (eggs, nauplii, copepodids, and adults) and including measurements on survival,

C. Barata; M. Medina; T. Telfer; D. J. Baird

2002-01-01

260

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

NASA Astrophysics Data System (ADS)

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

Pepin, Pierre

2013-05-01

261

Diversity and community structure of harpacticoid copepods associated with cold-water coral substrates in the Porcupine Seabight (North-East Atlantic)  

Microsoft Academic Search

The influence of microhabitat type on the diversity and community structure of the harpacticoid copepod fauna associated with\\u000a a cold-water coral degradation zone was investigated in the Porcupine Seabight (North-East Atlantic). Three substrate types\\u000a were distinguished: dead fragments of the cold-water coral Lophelia\\u000a pertusa, skeletons of the glass sponge Aphrocallistes bocagei and the underlying sediment. At the family level, it

Hendrik Gheerardyn; Marleen De Troch; Magda Vincx; Ann Vanreusel

2010-01-01

262

The impact of metazooplankton on the structure of the microbial food web in a shallow, hypertrophic lake  

Microsoft Academic Search

Shallow, hypertrophic Lake Søbygård is characterized by strong fluctuations in the plankton community structure over short time scales, and cascading predation effects from higher to lower trophic levels. We examined the coupling between the classical and microbial food web for a 1 month period, during which the typical zooplankton summer succession from rotifers (mainly Brachionus spp.) to cyclopoid copepods and

Klaus Jürgens; Erik Jeppesen

2000-01-01

263

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

Microsoft Academic Search

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

John C. McGovern; John E. Olney

1988-01-01

264

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

Microsoft Academic Search

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

Lee A. Kissick

1987-01-01

265

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

PubMed

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

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

2014-11-01

266

Chemical composition and energy content of deep-sea calanoid copepods in the Western North Pacific Ocean  

NASA Astrophysics Data System (ADS)

Condition factor index [CFI=1000×DW/(PL) 3; DW: dry weight, PL: prosome length], water content, carbon (C), nitrogen (N), ash and energy content were determined on a total of 69 copepod species caught from the mesopelagic (500-1000 m), upper-bathypelagic (1000-2000 m), lower-bathypelagic (2000-3000 m) and abyssopelagic (3000-5000 m) zones of the western subarctic Pacific. Resultant data were grouped into these four sampling zones, four developmental stage/sex categories (C4, C5 and C6 females and males), three feeding types (carnivore, detritivore and suspension feeder), or two reaction speed groups by the presence/absence of myelinated sheath enveloping axons (fast and slow reacting species). Zone-structured data showed the overall ranges were 3.8-4.6 mm for PL, 1.6-2.6 mg for DW, 21.4-25.0 for CFI, 75.0-78.6% of wet weight (WW) for water, 51.3-53.7% of DW for C, 7.7-8.8% of DW for N, 6.2-7.0 (by weight) for C/N, 6.9-9.6% of DW for ash and 25.3-27.4 J mg -1 DW for energy. Among these components, N and ash exhibited significant between-zone differences characterized by gradual decrease downward for the former, and only the upper-bathypelagic zone>abyssopelagic zone for the latter. Stage/sex-structured data showed no significant differences among them, but energy content of C5 was higher than that of C6 females. From the analyses of feeding type-structured data, carnivores were shown to have lower water, N, ash, but higher C, C/N and energy contents than suspension feeders do. Reaction speed-structured data indicated that slow-reacting species have significantly higher water but lower CFI, C, N and energy contents than fast-reacting species. Designating these grouping criteria, PL and DW as independent variables, the attributes of these variables to the CFI, chemical composition or energy contents were evaluated by stepwise-multiple regression analysis, showing the most pronounced effect of suspension-feeder, followed by the presence of myelinated sheath, DW, C6 females and the abyssopelagic zone. Further analysis of zone-structured data, by adding epipelagic copepod data from identical thermal habitats (Arctic/Antarctic waters), revealed a more marked decline in N content from the epipelagic zone to the abyssopelagic zone, accompanied by an increase in C/N ratios downward. The decline in N (=protein or muscle) contents with depth cannot be explained by the "visual interactions" hypotheses being proposed for the metabolism of pelagic visual predators, but is consistent with the "predation-mediated selection" hypothesis for the metabolism of pelagic copepods.

Ikeda, Tsutomu; Yamaguchi, Atsushi; Matsuishi, Takashi

2006-11-01

267

Gamma rays induce DNA damage and oxidative stress associated with impaired growth and reproduction in the copepod Tigriopus japonicus.  

PubMed

Nuclear radioisotope accidents are potentially ecologically devastating due to their impact on marine organisms. To examine the effects of exposure of a marine organism to radioisotopes, we irradiated the intertidal copepod Tigriopus japonicus with several doses of gamma radiation and analyzed the effects on mortality, fecundity, and molting by assessing antioxidant enzyme activities and gene expression patterns. No mortality was observed at 96h, even in response to exposure to a high dose (800Gy) of radiation, but mortality rate was significantly increased 120h (5 days) after exposure to 600 or 800Gy gamma ray radiation. We observed a dose-dependent reduction in fecundity of ovigerous females; even the group irradiated with 50Gy showed a significant reduction in fecundity, suggesting that gamma rays are likely to have a population level effect. In addition, we observed growth retardation, particularly at the nauplius stage, in individuals after gamma irradiation. In fact, nauplii irradiated with more than 200Gy, though able to molt to copepodite stage 1, did not develop into adults. Upon gamma radiation, T. japonicus showed a dose-dependent increase in reactive oxygen species (ROS) levels, the activities of several antioxidant enzymes, and expression of double-stranded DNA break damage genes (e.g. DNA-PK, Ku70, Ku80). At a low level (sub-lethal dose) of gamma irradiation, we found dose-dependent upregulation of p53, implying cellular damage in T. japonicus in response to sub-lethal doses of gamma irradiation, suggesting that T. japonicus is not susceptible to sub-lethal doses of gamma irradiation. Additionally, antioxidant genes, phase II enzyme (e.g. GSTs), and cellular chaperone genes (e.g. Hsps) that are involved in cellular defense mechanisms also showed the same expression patterns for sublethal doses of gamma irradiation (50-200Gy). These findings indicate that sublethal doses of gamma radiation can induce oxidative stress-mediated DNA damage and increase the expression of antioxidant enzymes and proteins with chaperone-related functions, thereby significantly affecting life history parameters such as fecundity and molting in the copepod T. japonicus. PMID:24800869

Han, Jeonghoon; Won, Eun-Ji; Lee, Bo-Young; Hwang, Un-Ki; Kim, Il-Chan; Yim, Joung Han; Leung, Kenneth Mei Yee; Lee, Yong Sung; Lee, Jae-Seong

2014-07-01

268

Natural copepods are superior to enriched artemia nauplii as feed for halibut larvae (Hippoglossus hippoglossus) in terms of survival, pigmentation and retinal morphology: relation to dietary essential fatty acids.  

PubMed

Replicate groups of halibut larvae were fed to d 71 post-first feeding (PFF) either the marine copepod, Eurytemora velox, or Artemia nauplii doubly enriched with the marine chromist or golden algae, Schizochytrium sp., (Algamac 2000) and a commercial oil emulsion (SuperSelco). The fatty acid compositions of eyes, brains and livers from larvae fed the two diets were measured, and indices of growth, eye migration and skin pigmentation were recorded along with histological examinations of eye and liver. The docosahexaenoic acid [22:6(n-3); DHA]/eicosapentaenoic acid [20:5(n-3); EPA] ratios in Artemia nauplii enriched with the SuperSelco and Algamac 2000 were 0.4 and 1.0, respectively. The E. velox copepods were divided into two size ranges (125-250 and 250-400 microm) with the smaller size range containing the highest level of (n-3) highly unsaturated fatty acids (HUFA). The DHA/EPA ratios for the two size ranges of copepods were 2.0 and 0.9, respectively. The total lipids of eyes, brains and livers of larvae fed copepods had higher levels of DHA and lower levels of EPA than those of larvae fed enriched Artemia. The percentage of survival of the halibut larvae was significantly higher when copepods rather than enriched Artemia nauplii were fed, but larval specific growth rates did not differ. The indices of eye migration were high and not significantly different in larvae fed the two diets, but the percentage of larvae undergoing successful metamorphosis (complete eye migration and dorsal pigmentation) was higher in larvae fed copepods (40%) than in larvae fed enriched Artemia (4%). The rod/cone ratios in histological sections of the retina were 2.5 +/- 0.7 in larvae fed copepods and 1.3 +/- 0.6 in larvae fed enriched Artemia (P < 0.01). Histological examination of the livers and intestines of the larvae were consistent with better assimilation of lipid from copepods than lipid from Artemia nauplii up to 46 d post-first feeding. Thus, marine copepods are superior to enriched Artemia as food for halibut larvae in terms of survival, eye development and pigmentation, and this superiority can be related to the level of DHA in the feed. PMID:10356085

Shields, R J; Bell, J G; Luizi, F S; Gara, B; Bromage, N R; Sargent, J R

1999-06-01

269

Multigenerational exposure to ocean acidification during food limitation reveals consequences for copepod scope for growth and vital rates.  

PubMed

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

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

2014-10-21

270

A new species of parasitic copepod Nothobomolochus and redescription of Orbitacolax hapalogenyos (Yamaguti and Yamasu, 1959) (Cyclopoida: Bomolochidae) off Iraq.  

PubMed

A new species of bomolochid copepod Nothobomolochus ilhoikimi sp. n., (Cyclopoida), is described based on adult females collected from the gills of hilsa shad Tenualosa ilisha (Hamilton) (Actinopterygii, Clupeidae) captured in waters off Iraq. The new species differs from its congeners by having the following combination of characters in the adult female: 1) anal somite not spinulate; 2) paragnath blunt and robust; 3) maxilla with slender proximal segment and distal segment with 2 accessory processes terminally; 4) the distal exopodal segment of leg 1 with 3 small spines; and 5) the terminal endopodal segment of leg 4 carrying one long and one short spine. It closely resembles N. triceros (Bassett-Smith, 1898) but prominently differs in above features and also in host specificity. In addition, another bomolochid Orbitacolax hapalogenyos (Yamaguti and Yamasu, 1959) is redescribed based on material collected from Japanese threadfin bream Nemipterus japonicus (Bloch) (Perciformes, Nemipteridae) captured in waters off Iraq. Two species clusters, the hapalogenyos and the analogus groups are recognized in this genus. PMID:25236279

Maran, Balu Alagar Venmathi; Moon, Seong Yong; Adday, Thamir K; Khamees, Najim R; Myoung, Jung-Goo

2014-10-01

271

Infestation of gill copepod Lernanthropus latis (Copepoda: Lernanthropidae) and its effect on cage-cultured Asian sea bass Lates calcarifer.  

PubMed

Twenty Asian sea bass Lates calcarifer from a floating cage in Bt. Tambun, Penang were examined for the presence of parasitic gill copepod, Lernanthropus latis. The prevalence of L. latis was 100% with the intensity of infection ranging from 1 to 18 parasites per host or 3.75 of mean intensity. Female parasites having oblong cephalothorax and egg-strings were seen mainly on the entire gill of examined Asian sea bass. The infected gill of Asian sea bass was pale and had eccessive mucus production. Under light and scanning electron microscopies (SEM), L. latis was seen grasping or holding tightly to the gill filament using their antenna, maxilla and maxilliped. These structures are characteristically prehensile and uncinate for the parasite to attach onto the host tissue. The damage was clearly seen under SEM as the hooked end of the antenna was embedded into the gill filament. The parasite also has the mandible which is styliform with eight teeth on the inner margin. The pathological effects such as erosion, haemorrhages, hyperplasia and necrosis along the secondary lamellae of gill filaments were seen and more severe at the attachment site. The combined actions of the antenna, maxilla and maxilliped together with the mandible resulted in extensive damage as L. latis attached and fed on the host tissues. PMID:23018508

Kua, B C; Noraziah, M R; Nik Rahimah, A R

2012-09-01

272

Carotenoid metabolic profiling and transcriptome-genome mining reveal functional equivalence among blue-pigmented copepods and appendicularia.  

PubMed

The tropical oligotrophic oceanic areas are characterized by high water transparency and annual solar radiation. Under these conditions, a large number of phylogenetically diverse mesozooplankton species living in the surface waters (neuston) are found to be blue pigmented. In the present study, we focused on understanding the metabolic and genetic basis of the observed blue phenotype functional equivalence between the blue-pigmented organisms from the phylum Arthropoda, subclass Copepoda (Acartia fossae) and the phylum Chordata, class Appendicularia (Oikopleura dioica) in the Red Sea. Previous studies have shown that carotenoid-protein complexes are responsible for blue coloration in crustaceans. Therefore, we performed carotenoid metabolic profiling using both targeted and nontargeted (high-resolution mass spectrometry) approaches in four different blue-pigmented genera of copepods and one blue-pigmented species of appendicularia. Astaxanthin was found to be the principal carotenoid in all the species. The pathway analysis showed that all the species can synthesize astaxanthin from ?-carotene, ingested from dietary sources, via 3-hydroxyechinenone, canthaxanthin, zeaxanthin, adonirubin or adonixanthin. Further, using de novo assembled transcriptome of blue A. fossae (subclass Copepoda), we identified highly expressed homologous ?-carotene hydroxylase enzymes and putative carotenoid-binding proteins responsible for astaxanthin formation and the blue phenotype. In blue O. dioica (class Appendicularia), corresponding putative genes were identified from the reference genome. Collectively, our data provide molecular evidences for the bioconversion and accumulation of blue astaxanthin-protein complexes underpinning the observed ecological functional equivalence and adaptive convergence among neustonic mesozooplankton. PMID:24803335

Mojib, Nazia; Amad, Maan; Thimma, Manjula; Aldanondo, Naroa; Kumaran, Mande; Irigoien, Xabier

2014-06-01

273

Meiobenthic diversity in space and time: The case of harpacticoid copepods in two Mediterranean microtidal sandy beaches  

NASA Astrophysics Data System (ADS)

Meiobenthic data from two microtidal sandy beaches of the eastern Mediterranean (Crete, Greece) were used to investigate patterns of both alpha and beta diversity in space and time. Copepod assemblages and environmental variables related to sediment characteristics, morphodynamics and food were studied over a year at four distinct habitats at each beach; the retention, resurgence and saturation zones of Salvat's intertidal scheme (midlittoral zone), and the surf zone of the sublittoral. ?lpha diversity analysis indicated similar species richness at both beaches when the whole 13-month data set was considered but was higher at the sheltered site when each sampling period was examined separately. Both beaches supported higher diversity in the sublittoral zone. Species richness increased seawards at the midlittoral zone of the sheltered site whereas, no pattern was evident at the exposed site, where the intense hydrodynamic conditions homogenized the sediments. Beta diversity increased markedly towards the sublittoral, indicating greater differences in alpha diversity between the sublittoral and the midlittoral zone. Species turnover was more variable at the exposed beach and at the most landward stations, where environmental conditions change often between extremes. A proportion of the variation in alpha diversity was explained by food availability at both beaches and additionally by grain size at the sheltered site. However, no environmental variable explained beta diversity patterns. Although the results of our study support the hypothesis of Multicausal Environmental Severity proposed for sandy beach macrofauna, we believe the classic Intermediate Disturbance Hypothesis is a more appropriate framework for the meiofauna communities of the studied sites.

Sevastou, Katerina; Lampadariou, Nikolaos; Eleftheriou, Anastasios

2011-10-01

274

The jet off Point Arena, California: Its role in aspects of secondary production in the copepod Eucalanus californicus Johnson  

NASA Astrophysics Data System (ADS)

The most abundant large herbivorous copepod in the jet off Point Arena, California, was Eucalanus californicus. In July 1988, females were actively laying eggs and also had a sac of stored lipid. If egg production is a function of present food supply, food concentrations within the jet become the primary factor governing egg laying. However, if stored lipid is the nutritive source for egg production, the critical food supply governing egg laying can be quite distant in space and time from the actual egg laying. In this jet, present food concentration was the factor governing egg production. The size of the lipid sac was also positively correlated with egg production, suggesting that lipid was not being used for oogenesis. Such a life history strategy, in which egg laying and lipid storage are proceeding concurrently in females, has not been described before. Reproductive females were found primarily nearshore and along the southern edge of the jet; highest rates of egg laying and largest lipid reserves were also in these areas. We speculate that temperature affinities of Eucalanus californicus result in maximized abundance, egg production, and lipid sequestration at temperatures below approximately 13°C. In the Point Arena region, this results in a nearshore portion of the population inhabiting surface layers and showing potential for very high rates of secondary production. The jet acts to transport E. californicus from the nearshore zone into its offshore habitat on a regular basis. Eddies in the region may be the mechanism by which E. californicus is returned to the nearshore zone.

Smith, Sharon L.; Lane, Peter V. Z.

1991-08-01

275

Life history strategies in zooplankton communities: The significance of female gonad morphology and maturation types for the reproductive biology of marine calanoid copepods  

NASA Astrophysics Data System (ADS)

The present review addresses the reproductive strategies of marine calanoid copepods, as affected by their physiological preconditioning, and aims to enhance understanding of their adaptations to specific environmental conditions. Knowledge about oocyte development and internal gonad structure, especially in relation to feeding conditions, is essential for a complete understanding of the reproductive strategies of the copepods. Therefore, the foci of the review are to identify general patterns in oocyte and gonad development in calanoid copepod species from marine ecosystems worldwide and to elucidate the significance of gonad structures for reproductive strategies. Oogenesis is similar in all copepod species. During maturation, the morphology of the oocytes changes distinctly and, according to oocyte size and appearance of ooplasm and nucleus, five oocyte developmental stages are distinguished. In contrast, the gonad structure and its changes during the spawning cycle differ considerably among species, and these differences are related to specific reproductive traits. Four gonad morphology types can be distinguished: the Calanus-type, found in species from all over the world with distinctly different life history traits, is apparently most common in calanoid copepods. In this gonad type, most oocyte developmental stages are present simultaneously, and usually many oocytes mature synchronously, all of which are released in one clutch. The gonad structure allows frequent spawning and large clutches, hence, high egg production rates. This may be a preconditioning for exploiting seasonally high food supply. However, the Calanus-type was also found in species producing eggs at lower rates. In the diverticula of Pseudocalanus-type gonads, only two oocyte developmental stages are present and usually fewer oocytes mature synchronously. Accordingly, the egg production rate is generally lower as compared to the Calanus-type, and apparently only this gonad-type is structurally suitable for ovigerity. Species with Pseudocalanus-type gonads are present from polar seas to the tropics, some of them being key species. The Acartia-type was scarce, found in only one species, Acartia clausi. Here all oocyte developmental stages are present, including intermediate stages, but only a few oocytes mature synchronously and are released together. High spawning frequency compensates for the small clutches, and hence egg production rate may be as high as in Calanus-type gonads. In the Aetidius-type gonad, the total number of oocytes in the diverticula is low as is the number of oocytes maturing synchronously. Less is known about the reproductive biology of species with Aetidius-type gonads; however, their distribution and feeding patterns suggest that this type is common in species inhabiting environments of low food availability. The differences in gonad structures also lead to differences in the egg size:female size ratio, as the space available for each mature oocyte depends on the total number of oocytes. Independent from gonad-type, the eggs are relatively large in species in which the gonads contain only few oocytes, whereas small eggs are produced by species with gonads filled with many oocytes. Since all species carrying their eggs in external sacs until hatching (ovigerous species) have Pseudocalanus-type gonads, the scatter in their egg size:female size ratio is low. The broadcast spawning species are of all gonad-types, and consequently the scatter among them is high. A major factor affecting the timing and magnitude of spawning of calanoid copepods is the energy supply for gonad development. Therefore, part of the review elucidates the role of internal and external resources in fuelling egg production. In many species, freshly assimilated food is transferred into egg material within a short period of time, and clutch size and spawning frequency are the two parameters that allow adjustment of egg production to food availability and temperature. However, internal body reserves may also fuel oocyte development. The extent to which oogene

Niehoff, Barbara

2007-07-01

276

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

SciTech Connect

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

Fell, J.W.; Cefalu, R.

1984-01-01

277

A new species of parasitic copepod, Sarcotretes umitakae sp. n. (Siphonostomatoida, Pennellidae), on the rattail (Actinopterygii, Macrouridae) from the East China Sea, Japan.  

PubMed

A new species of copepod, Sarcotretes umitakaesp. n., of the siphonostomatoid family Pennellidae is described based on female specimens from the rattail Coelorinchus jordani Smith and Pope (Actinopterygii: Gadiformes: Macrouridae) caught in the East China Sea. This species is characterized by exhibiting the following characters: the large proboscis projects strongly; the head bears paired lateral processes which are bulbous and taper into a slender horn; the twisting neck is significantly longer than the trunk; and the trunk bears an anterior constriction with a reduced abdomen. PMID:23275747

Uyeno, Daisuke; Wakabayashi, Kaori; Nagasawa, Kazuya

2012-01-01

278

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

PubMed Central

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

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

2014-01-01

279

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

280

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

NASA Astrophysics Data System (ADS)

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

Noyon, Margaux; William Froneman, P.

2013-12-01

281

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

PubMed Central

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

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

2014-01-01

282

Identification and developmental expression of the enzymes responsible for dopamine, histamine, octopamine and serotonin biosynthesis in the copepod crustacean Calanus finmarchicus  

PubMed Central

Neurochemicals are likely to play key roles in physiological/behavioral control in the copepod crustacean Calanus finmarchicus, the biomass dominant zooplankton for much of the North Atlantic Ocean. Previously, a de novo assembled transcriptome consisting of 206,041 unique sequences was used to characterize the peptidergic signaling systems of Calanus. Here, this assembly was mined for transcripts encoding enzymes involved in amine biosynthesis. Using known Drosophila melanogaster proteins as templates, transcripts encoding putative Calanus homologs of tryptophan-phenylalanine hydroxylase (dopamine, octopamine and serotonin biosynthesis), tyrosine hydroxylase (dopamine biosynthesis), DOPA decarboxylase (dopamine and serotonin biosynthesis), histidine decarboxylase (histamine biosynthesis), tyrosine decarboxylase (octopamine biosynthesis), tyramine ?-hydroxylase (octopamine biosynthesis) and tryptophan hydroxylase (serotonin biosynthesis) were identified. Reverse BLAST and domain analyses show that the proteins deduced from these transcripts possess sequence homology to and the structural hallmarks of their respective enzyme families. Developmental profiling revealed a remarkably consistent pattern of expression for all transcripts, with the highest levels of expression typically seen in the early nauplius and early copepodite. These expression patterns suggest roles for amines during development, particularly in the metamorphic transitions from embryo to nauplius and from nauplius to copepodite. Taken collectively, the data presented here lay a strong foundation for future gene-based studies of aminergic signaling in this and other copepod species, in particular assessment of the roles they may play in developmental control. PMID:24148657

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

2013-01-01

283

Sinking particles as a possible source of nutrition for the large calanoid copepod Neocalanus cristatus in the subarctic Pacific Ocean  

NASA Astrophysics Data System (ADS)

Shipboard incubations of Neocalanus cristatus CV in natural seawater from the subarctic Pacific Ocean near Ocean Station "P" (50°N, 145°W) indicate that ingestion of uniformly suspended phytoplankton averages 6.3 ?gC cop -1 day -1 and ingestion of protozoan microzooplankton is 3.0-4.6 ?gC cop -1 day -1. Metazoan microzooplankton may contribute an additional 2.1-4.3 ?gC cop -1 day -1. Total ingestion from these sources is considerably less than the 34-92 ?gC cop -1 day -1 required for a growth rate of only 2% body C day -1. Levels of gut chlorophyll and pheopigments indicate ingestion rates of pigment containing materials were approximately four times greater than determined by in vitro incubations. Microscopic examination of gut contents suggests that aggregated particulate material was being ingested, and the morphology, behavior and vertical distribution of N. cristatus CV further suggest that sinking aggregates may be a significant source of nutrition: (a) N. cristatus CV has a large perceptive volume. It is a large copepod, 7-9 mm long from the apex of the head to the apex of the caudal rami, and its first antennae are disproportionately long relative to its body size. In addition, it has elaborate plumose setulation at the end of its antennae and its caudal furcae; (b) N. cristatus CV is a stationary suspension feeder. It hangs motionless in the water column for long periods and uses a feeding current to bring particles within the working range of its mouthparts. It is not an efficient carnivore; (c) N. cristatus CV is concentrated below the surface mixed layer (upper 30-50 m), in the depth stratum of maximum particulate flux. Measured levels of gut pigment in N. cristatus CV could be obtained by ingestion of the particulate flux from only a few cm 2 day -1. This would provide sufficient nutrition to maintain a growth rate consistent with known rates in this region.

Dagg, Michael

1993-07-01

284

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

NASA Astrophysics Data System (ADS)

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

Gowing, Marcia M.; Wishner, Karen F.

285

A new genus of speleophriid copepod (Copepoda: Misophrioida) from a cenote in the Yucatan, Mexico with a phylogenetic analysis at the species level.  

PubMed

A new genus and species of speleophriid copepod, Mexicophria cenoticola gen. et sp. nov., is described based on material collected from a cenote in the Yucatan Peninsula of Mexico. It is characterised by relatively reduced fifth legs that are located adjacent to the ventral midline in both sexes, by the possession of a bulbous swelling on the first antennulary segment in both sexes, and by the reduced setation of the swimming legs. The presence of just one inner margin seta on the second endopodal segment of legs 2 to 4 is a unique feature for the family. A phylogenetic analysis places the new genus on a basal lineage of the family together with its sister taxon, Boxshallia Huys, 1988, from Lanzarote in the Canary Islands, and recovers the existing genera as monophyletic units. The zoogeography is discussed at local, regional, ocean basin  and global scales. PMID:24989747

Boxshall, Geoff A; Zylinski, Sarah; Jaume, Damià; Iliffe, Thomas M; Suárez-Morales, Eduardo

2014-01-01

286

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

287

The effects of Orimulsion and Fuel Oil #6 on the hatching success of copepod resting eggs in the seabed of Tampa Bay, Florida.  

PubMed

A 3-month microcosm study was conducted to observe the potential effects of two fuels, Orimulsion and Fuel Oil #6, on the hatching success of copepod resting eggs in the seabed of Tampa Bay, Florida. Microcosms were dosed with one of five hydrocarbon treatments via hydrocarbon-coated sand and compared with controls. Acartia tonsa eggs were nonviable in all treatments after only a few weeks of incubation, as evidenced by a marked decline in the abundance of nauplii. However, there was no evidence that exposure to simulated spills of 700 or 7000 ppm of either fuel led to significant increases in resting egg mortality as compared with controls. The results further indicate that, regardless of environmental conditions, resting eggs of A. tonsa do not remain viable in the sediment for extended periods of time. PMID:12442802

Suderman, Barbara L; Marcus, Nancy H

2002-01-01

288

Isolation and characterization of bacteria from the copepod Pseudocaligus fugu ectoparasitic on the panther puffer Takifugu pardalis with the emphasis on TTX.  

PubMed

A total of 50 bacterial isolates was obtained from the copepod Pseudocaligus fugu, which is a common parasite, collected from the body surface of the panther puffer Takifugu pardalis. On the basis of colony characteristics, these bacterial isolates were grouped into six types, of which only two (Types-I and -II) showed a high affinity for adhesion to the carapace of the banana shrimp Penaeus merguiensis. These two types of adhesive bacteria were identified through 16S rRNA sequence analysis as Shewanella woodyi (Type-I) and Roseobacter sp. (Type-II). Representative isolates of these two adhesive bacteria were examined for tetrodotoxin (TTX) production by high-performance liquid chromatography (HPLC)-fluorometric system, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). It was rather unexpectedly revealed that TTX and anhydroTTX were present in the supernatant of culture of the Type-II isolate Roseobacter sp. PMID:17698158

Maran, B A Venmathi; Iwamoto, Emi; Okuda, Jun; Matsuda, Shuhei; Taniyama, Shigeto; Shida, Yasuo; Asakawa, Manabu; Ohtsuka, Susumu; Nakai, Toshihiro; Boxshall, Geoffrey A

2007-11-01

289

Three new records of copepods (Siphonostomatoida) parasitic on marine fishes of Iraq, including the relegation of two species of Lernanthropinus to Lernanthropinus temminckii (von Nordmann, 1864).  

PubMed

Three parasitic copepods (Siphonostomatoida) belonging to three different genera were recovered from marine fishes of Iraq, and are listed here as new records. The sea lice Caligus epinepheli Yamaguti, 1936 (Caligidae) was collected from the Japanese threadfin bream, Nemipterus japonicus (Bloch). It had been frequently reported from teleost fishes around the world. The second record, comprising male and female, was another caligid, rarely caught from fishes - Hermilius longicornis Bassett-Smith, 1898, collected from the giant catfish, Netuma thalassina (Rüppell). This paper features the first description of the male of the latter species. The third record was the lernanthropid, Lernanthropinus temminckii (von Nordmann, 1864) (Lernanthropidae), redescribed based on the specimens collected from the greater lizard fish, Saurida tumbil (Bloch) (Synodontidae). In order to clarify its taxonomic status, our specimen was compared with the holotype of L. gibbosus (Pillai, 1964) from the collections of Zoological Survey of India, Kolkata, and the syntypes of L. sauridae Do in Ho and Do, 1985 and L. temminckii from the collections of the Smithsonian Institution, Washington D.C. We found similarities in the morphology of the body, mouthparts, and legs 1-4 in three above-mentioned species. The prominent feature, the setation pattern of legs 1 and 2 was similar in all the female specimens examined. In the light of this, we formally relegate L. gibbosus and L. sauridae to synonymy with L. temminckii. Another important similarity is that Lernanthropinus gibbosus, L. sauridae, and L. temminckii have exclusively been parasitic on lizardfishes (Synodontidae). The attachment site of all three copepods reported form Iraq were the gill filaments. PMID:24570061

Venmathi Maran, B A; Moon, Seong Yong; Adday, Thamir Katea; Khamees, Najim Rijab; Myoung, Jung-Goo

2014-03-01

290

A common-garden experiment to quantify evolutionary processes in copepods: the case of emamectin benzoate resistance in the parasitic sea louse Lepeophtheirus salmonis  

PubMed Central

Background The development of pesticide resistance represents a global challenge to food production. Specifically for the Atlantic salmon aquaculture industry, parasitic sea lice and their developing resistance to delousing chemicals is challenging production. In this study, seventeen full sibling families, established from three strains of Lepeophtheirus salmonis displaying differing backgrounds in emamectin benzoate (EB) tolerance were produced and quantitatively compared under a common-garden experimental design. Lice surviving to the preadult stage were then exposed to EB and finally identified through the application of DNA parentage testing. Results With the exception of two families (19 and 29%), survival from the infectious copepod to preadult stage was very similar among families (40-50%). In contrast, very large differences in survival following EB exposure were observed among the families (7.9-74%). Family survival post EB exposure was consistent with the EB tolerance characteristics of the strains from which they were established and no negative effect on infection success were detected in association with increased EB tolerance. Two of the lice families that displayed reduced sensitivity to EB were established from a commercial farm that had previously used this chemical. This demonstrates that resistant alleles were present on this farm even though the farm had not reported treatment failure. Conclusions To our knowledge, this represents the first study where families of any multi-cellular parasite have been established and compared in performance under communal rearing conditions in a common-garden experiment. The system performed in a predictable manner and permitted, for the first time, elucidation of quantitative traits among sea lice families. While this experiment concentrated on, and provided a unique insight into EB sensitivity among lice families, the experimental design represents a novel methodology to experimentally address both resistance development and other evolutionary questions in parasitic copepods. PMID:24885085

2014-01-01

291

Gene expression analyses of immune responses in Atlantic salmon during early stages of infection by salmon louse ( Lepeophtheirus salmonis ) revealed bi-phasic responses coinciding with the copepod-chalimus transition  

Microsoft Academic Search

Background  The salmon louse (Lepeophtheirus salmonis Krøyer), an ectoparasitic copepod with a complex life cycle causes significant losses in salmon aquaculture. Pesticide treatments\\u000a against the parasite raise environmental concerns and their efficacy is gradually decreasing. Improvement of fish resistance\\u000a to lice, through biological control methods, needs better understanding of the protective mechanisms. We used a 21 k oligonucleotide\\u000a microarray and RT-qPCR

Tariku Markos Tadiso; Aleksei Krasnov; Stanko Skugor; Sergey Afanasyev; Ivar Hordvik; Frank Nilsen

2011-01-01

292

Transmission Ecology and Larval Behaviour of Camallanus cotti (Nematoda, Camallanidae) Under Aquarium Conditions  

Microsoft Academic Search

The parasitic fish nematode Camallanus cotti has been reported from a number of freshwater fish species around the world. Its wide geographical distribution seems mainly\\u000a to be the result of anthropogenic dissemination due to extensive ornamental fish trade. In most reports it is assumed that\\u000a C. cotti's life cycle involves cyclopoid copepods as intermediate host and various freshwater fishes as

Arne Levsen

2001-01-01

293

Food habits of small fishes in a common reed Phragmites australis belt in Lake Shinji, Shimane, Japan  

Microsoft Academic Search

To clarify the feeding habits of reed fishes, the gut contents of 13 fish species collected in a Phragmites australis belt in Lake Shinji were examined. Six species showed ontogenetic and\\/or seasonal changes in food use patterns. Smaller individuals\\u000a generally preyed on small planktonic items (e.g., calanoid and cyclopoid copepods) or small crustaceans (gammaridean amphipods),\\u000a subsequently changing to other prey

Masahiro Horinouchi; Gen Kume; Atsuko Yamaguchi; Kenji Toda; Kengo Kurata

2008-01-01

294

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

295

Successful colonization of the calanoid copepod Acartia tonsa in the oligo-mesohaline area of the Gironde estuary (SW France) Natural or anthropogenic forcing?  

NASA Astrophysics Data System (ADS)

The copepod Acartia tonsa appeared in Europe in the first half of the 20th century and colonized progressively European seas and estuaries, possibly transferred from North Atlantic Coast of America. It had been reported in the polyhaline area of the Gironde estuary for a long time but was first recorded in the oligo-mesohaline area in 1983. Its abundance has been increasing significantly. High abundances of A. tonsa were reported since 1999, supplanting the abundances of its autochthonous congeneric species, Acartia bifilosa. This colonization was characterized by analyzing the mean seasonal variability: (1) for three 5-year periods corresponding to three different steps of A. tonsa appearance (1978-1982, A. tonsa was absent; 1988-1992, low abundances of the species; and 1999-2003, high abundances of A. tonsa) in the oligo-mesohaline area and (2) for three stations distributed along the salinity gradient during the recent period. The aim of this work was to define if this colonization was due to natural or anthropogenic forcing and to evaluate its possible impact on autochthonous zooplanktonic community. Both natural and anthropogenic forcings seem to explain the colonization of Acartia tonsa in the oligo-mesohaline area of the Gironde estuary. First records (1983-1988) could be due to marine water inputs caused by high values of the North Atlantic Oscillation index. The global warming which caused the increase of the summer warm period, the marinisation of the system and the local decrease of the turbidity should have been the key factors favoring the establishment of the species. Anthropogenic forcings as the establishment of the nuclear power plant which locally causes warmer conditions are also important factors explaining the differences of seasonal cycle observed between oligo-mesohaline area and other stations: the seasonal pattern of A. tonsa in the oligo-mesohaline area was indeed characterized by an autumnal peak of abundances which has been observed in other stations and in many North European estuaries, and by a second spring peak that had only been observed in Southern estuaries. The introduction of Acartia tonsa in the Gironde estuary significantly changed the seasonal pattern of autochthonous copepods, by limiting their seasonal abundances without affecting their long-term population stability. Finally, the successful colonization of A. tonsa had led to the spread of the seasonal zooplanktonic production which could have had an impact on fish and shrimp productions.

David, Valérie; Sautour, Benoît; Chardy, Pierre

2007-02-01

296

Cloning and expression of cDNA for a luciferase from the marine copepod Metridia longa. A novel secreted bioluminescent reporter enzyme.  

PubMed

Metridia longa is a marine copepod from which a blue bioluminescence originates as a secretion from epidermal glands in response to various stimuli. We demonstrate that Metridia luciferase is specific for coelenterazine to produce blue light (lambda(max) = 480 nm). Using an expression cDNA library and functional screening, we cloned and sequenced the cDNA encoding the Metridia luciferase. The cDNA is an 897-bp fragment with a 656-bp open reading frame, which encodes a 219-amino acid polypeptide with a molecular weight of 23,885. The polypeptide contains an N-terminal signal peptide of 17 amino acid residues for secretion. On expression of the Metridia luciferase gene in mammalian Chinese hamster ovary cells the luciferase is detected in the culture medium confirming the existence of a naturally occurring signal peptide for secretion in the cloned luciferase. The novel secreted luciferase was tested in a practical assay application in which the activity of A2a and NPY2 G-protein-coupled receptors was detected. These results clearly suggest that the secreted Metridia luciferase is well suited as a reporter for monitoring gene expression and, in particular, for the development of novel ultrahigh throughput screening technologies. PMID:14583604

Markova, Svetlana V; Golz, Stefan; Frank, Ludmila A; Kalthof, Bernd; Vysotski, Eugene S

2004-01-30

297

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

PubMed

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

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

2014-11-01

298

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

299

Needle in a haystack: involvement of the copepod PARACARTIA grani in the life-cycle of the oyster pathogen Marteilia refringens.  

PubMed

Marteilia refringens is a major pathogen of the European flat oyster, Ostrea edulis Linnaeus. Since its description, the life-cycle of this protozoan parasite has eluded discovery. Attempts to infect oysters experimentally have been unsuccessful and led to the hypothesis of a complex life-cycle involving several hosts. Knowledge of this life-cycle is of central importance in order to manage oyster disease. However, the exploration of M. refringens life-cycle has been previously limited by the detection tools available and the tremendous number of species to be screened in enzootic areas. In this study, these two restrictions were circumvented by the use of both molecular detection tools and a mesocosm with low biodiversity. Screening of the entire fauna of the pond for M. refringens DNA was systematically undertaken using PCR. Here, we show that the copepod Paracartia (Acartia) grani is a host of M. refringens. Not only was DNA of M. refringens consistently detected in P. grani but also the presence of the parasite in the ovarian tissues was demonstrated using in situ hybridization. Finally, successful experimental transmissions provided evidence that P. grani can be infected from infected flat oysters. PMID:11922433

Audemard, C; Le, Roux F; Barnaud, A; Collins, C; Sautour, B; Sauria, P G; de, Montaudouin X; Coustau, C; Combes, C; Berthe, F

2002-03-01

300

Medium-term exposure of the North Atlantic copepod Calanus finmarchicus (Gunnerus, 1770) to CO2-acidified seawater: effects on survival and development  

NASA Astrophysics Data System (ADS)

The impact of medium-term exposure to CO2-acidified seawater on survival, growth and development was investigated in the North Atlantic copepod Calanus finmarchicus. Using a custom developed experimental system, fertilized eggs and subsequent development stages were exposed to normal seawater (390 ppm CO2) or one of three different levels of CO2-induced acidification (3300, 7300, 9700 ppm CO2). Following the 28-day exposure period, survival was found to be unaffected by exposure to 3300 ppm CO2, but significantly reduced at 7300 and 9700 ppm CO2. Also, the proportion of copepodite stages IV to VI observed in the different treatments was significantly affected in a manner that may indicate a CO2-induced retardation of the rate of ontogenetic development. Morphometric analysis revealed a significant increase in size (prosome length) and lipid storage volume in stage IV copepodites exposed to 3300 ppm CO2 and reduced size in stage III copepodites exposed to 7300 ppm CO2. Together, the findings indicate that a pCO2 level ?2000 ppm (the highest CO2 level expected by the year 2300) will probably not directly affect survival in C. finmarchicus. Longer term experiments at more moderate CO2 levels are, however, necessary before the possibility that growth and development may be affected below 2000 ppm CO2 can be ruled out.

Pedersen, S. A.; Hansen, B. H.; Altin, D.; Olsen, A. J.

2013-11-01

301

Chronic exposure of the North Atlantic copepod Calanus finmarchicus (Gunnerus, 1770) to CO2-acidified seawater; effects on survival, growth and development  

NASA Astrophysics Data System (ADS)

The impact of chronic exposure to CO2-acidified seawater on survival, growth and development was investigated in the North Atlantic copepod Calanus finmarchicus. Using a custom developed microcosm system fertilized eggs and subsequent development stages were exposed to normal seawater (390 ppm CO2) or one of three different levels of CO2-induced acidification (3300, 7300, 9700 ppm CO2). Following the 28 day exposure period survival was found to be unaffected by exposure to 3300 ppm CO2, but significantly reduced at 7300 and 9700 ppm CO2. Also, the proportion of copepodite stages IV to VI observed in the different treatments was significantly affected in a manner that may indicate a CO2-induced retardation of the rate of ontogenetic development. Morphometric analysis revealed a significant increase in size (prosome length) and lipid storage volume in stage IV copepodites exposed to 3300 ppm CO2 and reduced size in stage III copepodites exposed to 7300 ppm CO2. Together, the findings indicate that a pCO2 level ?2000 ppm (the highest CO2 level expected within year 2300) will probably not directly affect survival in C. finmarchicus. Long-term experiments at more moderate CO2 levels are however necessary before the possibility that growth and development may be affected below ?2000 ppm CO2 can be ruled out.

Pedersen, S. A.; Hansen, B. H.; Altin, D.; Olsen, A. J.

2013-03-01

302

The smallest natural high-active luciferase: Cloning and characterization of novel 16.5-kDa luciferase from copepod Metridia longa.  

PubMed

Coelenterazine-dependent copepod luciferases containing natural signal peptide for secretion are a very convenient analytical tool as they enable monitoring of intracellular events with high sensitivity, without destroying cells or tissues. This property is well suited for application in biomedical research and development of cell-based assays for high throughput screening. We report the cloning of cDNA gene encoding a novel secreted non-allelic 16.5-kDa isoform (MLuc7) of Metridia longa luciferase, which, in fact, is the smallest natural luciferase of known for today. Despite the small size, isoform contains 10 conservative Cys residues suggesting the presence of up to 5 SS bonds. This hampers the efficient production of functionally active recombinant luciferase in bacterial expression systems. With the use of the baculovirus expression system, we produced substantial amounts of the proper folded MLuc7 luciferase with a yield of ?3mg/L of a high purity protein. We demonstrate that MLuc7 produced in insect cells is highly active and extremely thermostable, and is well suited as a secreted reporter when expressed in mammalian cells ensuring higher sensitivity of detection as compared to another Metridia luciferase isoform (MLuc164) which is widely employed in real-time imaging. PMID:25543059

Markova, Svetlana V; Larionova, Marina D; Burakova, Ludmila P; Vysotski, Eugene S

2015-01-30

303

High resolution vertical distribution of the copepod Calanus chilensis in relation to the shallow oxygen minimum zone off northern Peru using LOKI, a new plankton imaging system  

NASA Astrophysics Data System (ADS)

The vertical distribution of copepodite stage V and adult Calanus chilensis was studied on two transects across the Humboldt Current System off northern Peru using the LOKI system. LOKI is an optical plankton recorder, which simultaneously collects images of zooplankton and environmental data such as temperature, salinity, oxygen, and fluorescence. Image quality allowed determination of CV, females and males and identification of C. chilensis from 3 co-occurring Calanid copepods. C. chilensis was inhabiting the upper 250 m. Highest abundances with a maximum of ca. 44.000 Ind. m-2 were observed in a narrow band within Cold Coastal Water at stations closest to the coast, coinciding with the Poleward Undercurrent. This raises questions for the life cycle closure within the Humboldt Current system. In contrast to observations in the southern part of the Humboldt Current System, the three stages studied were most abundant in hypoxic waters at oxygen concentrations between 5 and 50 ?M. Thus C. chilensis seems to be the only species of the family Calanidae where not only a resting stage can tolerate hypoxia, but also both adult stages. This impacts availability to predators, as despite a locally high biomass only part of the population is available to anchovy and other important fish species which are restricted to waters with higher oxygen concentrations.

Hirche, H. J.; Barz, K.; Ayon, P.; Schulz, J.

2014-06-01

304

Community structure of mesozooplankton in the western part of the Sea of Okhotsk in summer  

NASA Astrophysics Data System (ADS)

We investigated the community structure of mesozooplankton in the western part of the Sea of Okhotsk in late summer, 2006. We recognized four communities belonging to two assemblages. A coastal assemblage dominated by the arctic planktonic snail Limacina helicina consisted of a gulf community characterized by brackish copepods and a continental shelf community characterized by the hydrozoan medusa Aglantha digitale and the arctic copepod Calanus glacialis. The other assemblage, characterized by the oceanic copepod Neocalanus plumchrus, consisted of a continental slope community characterized by a diverse species composition and a basin community characterized by the oceanic copepod N. cristatus. The continental slope community contained species from the coastal waters and was distributed along the course of the East Sakhalin current. This community may have been assembled by the incorporation of coastal water into the oceanic waters by the strong current. Small coastal copepods such as Oithona similis and Pseudocalanus spp. were the main components in all communities in terms of numbers, but larger copepods such as Neocalanus spp. and Metridia okhotensis were important in terms of weight, especially in the continental slope and basin communities. The population structures of the dominant species suggest that overall biological production is maintained by continuous reproduction or growth (or both) of L. helicina and small coastal copepods after the onset of seasonal dormancy of the large oceanic copepods in late summer.

Itoh, Hiroshi; Nishioka, Jun; Tsuda, Atsushi

2014-08-01

305

Copepods in ice-covered seas—Distribution, adaptations to seasonally limited food, metabolism, growth patterns and life cycle strategies in polar seas  

NASA Astrophysics Data System (ADS)

While a seasonal ice cover limits light penetration into both polar seas for up to ten months a year, its presence is not entirely negative. The mixed layer under sea ice will generally be shallower than in open water at the same latitude and season. Ice forms a substrate on which primary production can be concentrated, a condition which contrasts with the generally dilute nutritional conditions which prevail in the remaining ocean. The combination of a shallow, generally stable mixed layer with a close proximity to abundant food make the under-ice zone a suitable nursery for both pelagic and benthic species, an upside-down benthos for opportunistic substrate browsers, and a rich feeding environment for species often considered to be neritic in temperate environments. Where the ice cover is not continuous there may be a retreating ice edge that facilitates the seasonal production of phytoplankton primarily through increased stability from the melt water. Ice edge blooms similarly encourage secondary production by pelagic animals. Pseudocalanus acuspes, which may be the most abundant and productive copepod in north polar latitudes, initiates growth at the start of the "spring bloom" of epontic algae, reaching sexual maturity at breakup or slightly before. In the Southern Hemisphere, the small neritic copepod Paralabidocera antarctica and adult krill have been observed to utilize ice algae. Calanus hyperboreus breeds in the dark season at depth and its buoyant eggs, slowly developing on the ascent, reach the under-ice layer in April as nauplii ready to benefit from the primary production there. On the other hand, C. glacialis may initiate ontogenetic migrations and reproduction in response to increased erosion of ice algae due to solar warming and melting at the ice-water interface. While the same species in a phytoplankton bloom near the ice edge reproduces actively, those under still-consolidated ice nearby can have immature gonads. Diel migration and diel feeding rhythms under or near the ice have also been observed for several species. In the Northern Hemisphere larger zooplanktonic species may take two, three, or possibly more years to reach maturity, but the grand strategy, apparently used by all, is to assure that their young have reached active feeding stages by the time of maximum primary production in the water column so that maximum growth, often, but not always, with emphasis on lipid storage, can occur during the often brief, but usually intense, summer bloom. The rate of growth of arctic or antarctic zooplankton is not so important as assuring a high level of fecundity when maturity comes. Overwintering is probably not a great hardship and diapause may not be a useful strategy because the environmental temperature is constantly near the freezing point of sea water, and basal metabolism accordingly low. Nonetheless, feeding behaviour and metabolic rates have strong seasonal signals. In the absence of other stimuli, light must be involved in the transformation from winter to summer metabolism and visa versa but the mechanisms still remain obscure.

Conover, R. J.; Huntley, M.

1991-07-01

306

Gene expression analyses of immune responses in Atlantic salmon during early stages of infection by salmon louse (Lepeophtheirus salmonis) revealed bi-phasic responses coinciding with the copepod-chalimus transition  

PubMed Central

Background The salmon louse (Lepeophtheirus salmonis Krøyer), an ectoparasitic copepod with a complex life cycle causes significant losses in salmon aquaculture. Pesticide treatments against the parasite raise environmental concerns and their efficacy is gradually decreasing. Improvement of fish resistance to lice, through biological control methods, needs better understanding of the protective mechanisms. We used a 21 k oligonucleotide microarray and RT-qPCR to examine the time-course of immune gene expression changes in salmon skin, spleen, and head kidney during the first 15 days after challenge, which encompassed the copepod and chalimus stages of lice development. Results Large scale and highly complex transcriptome responses were found already one day after infection (dpi). Many genes showed bi-phasic expression profiles with abrupt changes between 5 and 10 dpi (the copepod-chalimus transitions); the greatest fluctuations (up- and down-regulation) were seen in a large group of secretory splenic proteases with unknown roles. Rapid sensing was witnessed with induction of genes involved in innate immunity including lectins and enzymes of eicosanoid metabolism in skin and acute phase proteins in spleen. Transient (1-5 dpi) increase of T-cell receptor alpha, CD4-1, and possible regulators of lymphocyte differentiation suggested recruitment of T-cells of unidentified lineage to the skin. After 5 dpi the magnitude of transcriptomic responses decreased markedly in skin. Up-regulation of matrix metalloproteinases in all studied organs suggested establishment of a chronic inflammatory status. Up-regulation of putative lymphocyte G0/G1 switch proteins in spleen at 5 dpi, immunoglobulins at 15 dpi; and increase of IgM and IgT transcripts in skin indicated an onset of adaptive humoral immune responses, whereas MHCI appeared to be down-regulated. Conclusions Atlantic salmon develops rapid local and systemic reactions to L. salmonis, which, however, do not result in substantial level of protection. The dramatic changes observed after 5 dpi can be associated with metamorphosis of copepod, immune modulation by the parasite, or transition from innate to adaptive immune responses. PMID:21385383

2011-01-01

307

Effects of elevated carbon dioxide (CO2) concentrations on early developmental stages of the marine copepod Calanus finmarchicus Gunnerus (Copepoda: Calanoidae).  

PubMed

Ocean acidification poses an ongoing threat to marine organisms, and early life stages are believed to be particularly sensitive. The boreal calanoid copepod Calanus finmarchicus seasonally dominates the standing stock of zooplankton in the northern North Sea and North Atlantic, and due to its size and abundance is considered an ecological key species linking energy from primary producers to higher trophic levels. To examine whether the early stages of C. finmarchicus are particularly vulnerable to elevated levels of CO2, eggs and nauplii were subjected to different levels of CO2-acidified seawater for 1 wk. The first experiment, with eggs as the starting point, revealed no marked effect on hatching success, but a significant reduction in nauplii survival during incubation at 8800 ppm CO2. In addition, a significant decrease in ontogenetic development rate during incubation at 8800 ppm CO2 was observed in this experiment. In the second experiment, where third-stage nauplii represented the starting point, no significant effects on ontogenetic development and survival following exposure to pCO2 ? 7700 ppm were observed. Data suggest that the two first nauplii stages, which are fed endogenously, may be more vulnerable and therefore likely to represent the "bottleneck" for this species in a more acidic ocean. However, the absence of significant effects in the most sensitive stages during exposure to 2800 ppm CO2, a level that is well above worst-case scenario predictions for year 2300 (approximately 2000 ppm CO2), suggests that this species may be generally robust to direct effects of ocean acidification. PMID:24754390

Pedersen, Sindre Andre; Våge, Vegard Thorset; Olsen, Anders Johny; Hammer, Karen Marie; Altin, Dag

2014-01-01

308

Distribution of C-type allatostatin (C-AST)-like immunoreactivity in the central nervous system of the copepod Calanus finmarchicus  

PubMed Central

The C-type Allatostatins (C-ASTs) are a family of highly pleiotropic arthropod neuropeptides. In crustaceans, transcriptomic/mass spectral studies have identified C-ASTs in the nervous systems of many species; the cellular distributions of these peptides remain unknown. Here, the distribution of C-AST was mapped in the nervous system of the copepod Calanus finmarchicus, the major contributor to the North Atlantic’s zooplanktonic biomass; C-AST-immunopositive neurons were identified in the protocerebrum, in several peripheral ganglia associated with feeding appendages, and in the ganglia controlling the swimming legs, with immunopositive axons present throughout the ventral nerve cord. In addition, axons innervating the dorsal longitudinal and ventral longitudinal muscles of the body wall of the metasome were labeled by the C-AST antibody. While the distribution of C-AST-like immunoreactivity was similar between sexes, several differences were noted, i.e. two pair of somata located at the deutocerebral/tritocerbral border in males and immunopositive fibers that surround the genital opening in females. To place the C-AST-like labeling into context with those of several previously mapped peptides, i.e. A-type allatostatin (A-AST) and tachykinin-related peptide (TRP), we conducted double-labeling studies; the C-AST-like immunopositive neurons appear distinct from those expressing either A-AST or TRP (and through extrapolation, pigment dispersing hormone). Collectively, our data represent the first mapping of C-AST in crustacean neural tissue, show that sex-specific differences in the distribution of C-AST exist in the C. finmarchicus CNS, and suggest that the peptide may be involved in the modulation of both feeding and postural control/locomotion. PMID:20338176

Wilson, Caroline H.; Christie, Andrew E.

2010-01-01

309

Seasonal changes in zooplankton abundance, biomass, size structure and dominant copepods in the Oyashio region analysed by an optical plankton counter  

NASA Astrophysics Data System (ADS)

To identify seasonal patterns of change in zooplankton communities, an optical plankton counter (OPC) and microscopic analysis were utilised to characterise zooplankton samples collected from 0 to 150 m and 0 to 500 m in the Oyashio region every one to three months from 2002 to 2007. Based on the OPC measurements, the abundance and biomass of zooplankton peaked in June (0-150 m) or August (150-500 m), depending on the depth stratum. The peak periods of the copepod species that were dominant in terms of abundance and biomass indicated species-specific patterns. Three Neocalanus species (Neocalanus cristatus, Neocalanus flemingeri and Neocalanus plumchrus) exhibited abundance peaks that occurred before their biomass peaks, whereas Eucalanus bungii and Metridia pacifica experienced biomass peaks before their abundance peaks. The abundance peaks corresponded to the recruitment periods of early copepodid stages, whereas the biomass peaks corresponded to the periods when the dominant populations reached the late copepodid stages (C5 or C6). Because the reproduction of Neocalanus spp. occurred in the deep layer (>500 m), their biomass peaks were observed when the major populations reached stage C5 after the abundance peaks of the early copepodid stages. The reproduction of E. bungii and M. pacifica occurred near the surface layer. These species first formed biomass peaks of C6 and later developed abundance peaks of newly recruited early copepodid stages. From the comparison between OPC measurements and microscopic analyses, seasonal changes in zooplankton biomass at depths of 0-150 m were governed primarily by E. bungii and M. pacifica, whereas those at depths of 150-500 m were primarily caused by the three Neocalanus species.

Yamaguchi, Atsushi; Matsuno, Kohei; Abe, Yoshiyuki; Arima, Daichi; Ohgi, Kohei

2014-09-01

310

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

SciTech Connect

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

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

1994-09-01

311

Comparing seasonal dynamics of the Lake Huron zooplankton community between 1983-1984 and 2007 and revisiting the impact of Bythotrephes planktivory  

USGS Publications Warehouse

Zooplankton community composition can be influenced by lake productivity as well as planktivory by fish or invertebrates. Previous analyses based on long-term Lake Huron zooplankton data from August reported a shift in community composition between the 1980s and 2000s: proportional biomass of calanoid copepods increased while that of cyclopoid copepods and herbivorous cladocerans decreased. Herein, we used seasonally collected data from Lake Huron in 1983–1984 and 2007 and reported similar shifts in proportional biomass. We also used a series of generalized additive models to explore differences in seasonal abundance by species and found that all three cyclopoid copepod species (Diacyclops thomasi, Mesocylops edax, Tropocyclops prasinus mexicanus) exhibited higher abundance in 1983–1984 than in 2007. Surprisingly, only one (Epischura lacustris) of seven calanoid species exhibited higher abundance in 2007. The results for cladocerans were also mixed with Bosmina spp. exhibiting higher abundance in 1983–1984, while Daphnia galeata mendotae reached a higher level of abundance in 2007. We used a subset of the 2007 data to estimate not only the vertical distribution of Bythotrephes longimanus and their prey, but also the consumption by Bythotrephes in the top 20 m of water. This epilimnetic layer was dominated by copepod copepodites and nauplii, and consumption either exceeded (Hammond Bay site) or equaled 65% (Detour site) of epilimnetic zooplankton production. The lack of spatial overlap between Bythotrephes and herbivorous cladocerans and cyclopoid copepod prey casts doubt on the hypothesis that Bythotrephes planktivory was the primary driver underlying the community composition changes in the 2000s.

Bunnell, David B.; Keeler, Kevin M.; Puchala, Elizabeth A.; Davis, Bruce M.; Pothoven, Steven A.

2012-01-01

312

Gene expression in Atlantic salmon skin in response to infection with the parasitic copepod Lepeophtheirus salmonis, cortisol implant, and their combination  

PubMed Central

Background The salmon louse is an ectoparasitic copepod that causes major economic losses in the aquaculture industry of Atlantic salmon. This host displays a high level of susceptibility to lice which can be accounted for by several factors including stress. In addition, the parasite itself acts as a potent stressor of the host, and outcomes of infection can depend on biotic and abiotic factors that stimulate production of cortisol. Consequently, examination of responses to infection with this parasite, in addition to stress hormone regulation in Atlantic salmon, is vital for better understanding of the host pathogen interaction. Results Atlantic salmon post smolts were organised into four experimental groups: lice + cortisol, lice + placebo, no lice + cortisol, no lice + placebo. Infection levels were equal in both treatments upon termination of the experiment. Gene expression changes in skin were assessed with 21 k oligonucleotide microarray and qPCR at the chalimus stage 18 days post infection at 9°C. The transcriptomic effects of hormone treatment were significantly greater than lice-infection induced changes. Cortisol stimulated expression of genes involved in metabolism of steroids and amino acids, chaperones, responses to oxidative stress and eicosanoid metabolism and suppressed genes related to antigen presentation, B and T cells, antiviral and inflammatory responses. Cortisol and lice equally down-regulated a large panel of motor proteins that can be important for wound contraction. Cortisol also suppressed multiple genes involved in wound healing, parts of which were activated by the parasite. Down-regulation of collagens and other structural proteins was in parallel with the induction of proteinases that degrade extracellular matrix (MMP9 and MMP13). Cortisol reduced expression of genes encoding proteins involved in formation of various tissue structures, regulators of cell differentiation and growth factors. Conclusions These results suggest that cortisol-induced stress does not affect the level of infection of Atlantic salmon with the parasite, however, it may retard repair of skin. The cortisol induced changes are in close concordance with the existing concept of wound healing cascade. PMID:22480234

2012-01-01

313

Population modeling using harpacticoid copepods  

E-print Network

statistical power for reproductive endpoints, but at high labor and cost. Therefore were developed and applied to life-history data of Nitocra spinipes measuring life-history data. Additional experimental animals would improve

314

The zooplankton community in the Greenland Sea: Composition and role in carbon turnover  

NASA Astrophysics Data System (ADS)

The micro- and mesozooplankton communities in surface waters of the Greenland Sea are described based on data from five cruises covering an annual cycle. Special emphasis is given to the summer period (June and August), prior to and after the descent of Calanus spp. Calanus spp. dominated the copepod community during the spring bloom and in the beginning of the summer. However, during the summer, there was a pronounced shift in the zooplankton composition in the euphotic zone. In contrast to what has been observed in other Arctic systems, smaller genera such as Pseudocalanus spp., O ncaea spp. and Oithona spp. became abundant and the total copepod biomass remained high after the Calanus spp. descended for hibernation. The peak protozooplankton biomass in the Greenland Sea (June) co-occurred with the peak in Calanus spp. Protozooplankton biomass then decreased during the summer. Growth of protozooplankton and grazing rates of the two dominating non- Calanus genera, Oithona and Pseudocalanus, were measured. For both copepod genera, protozooplankton constituted 40% or more of the diet, and maximum clearance was on prey items with an equivalent spherical diameter between 15 and 30 ?m. The non- Calanus components of the zooplankton community were responsible for 70-99% of the total zooplankton grazing on phytoplankton during summer and were crucial for the recycling and respiration of primary production.

Møller, Eva Friis; Nielsen, Torkel Gissel; Richardson, Katherine

2006-01-01

315

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

PubMed

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

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

2012-01-01

316

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

317

Dose- and time-dependent expression of aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (ARNT) in PCB-, B[a]P-, and TBT-exposed intertidal copepod Tigriopus japonicus.  

PubMed

The aryl hydrocarbon receptor (AhR) and aryl hydrocarbon nuclear translocator (ARNT) genes from the copepod Tigriopus japonicus (Tj) were cloned to examine their potential functions in the invertebrate putative AhR-CYP signaling pathway. The amino acid sequences encoded by the Tj-AhR and Tj-ARNT genes showed high similarity to homologs of Daphnia and Drosophila, ranging from 68% and 70% similarity for the AhR genes to 56% for the ARNT genes. To determine whether Tj-AhR and Tj-ARNT are modulated by environmental pollutants, transcriptional expression of Tj-AhR and Tj-ARNT was analyzed in response to exposure to five concentrations of polychlorinated biphenyl (PCB 126) (control, 10, 50, 100, 500?gL(-1)), benzo[a]pyrene (B[a]P) (control, 5, 10, 50, 100?gL(-1)), and tributyltin (TBT) (control, 1, 5, 10, 20?gL(-1)) 24h after exposure. A time-course experiment (0, 3, 6, 12, 24h) was performed to analyze mRNA expression patterns after exposure to PCB, B[a]P, and TBT. T. japonicus exhibited dose-dependent and time-dependent upregulation of Tj-AhR and Tj-ARNT in response to pollutant exposure, and the degree of expression was dependent on the pollutant, suggesting that pollutants such as PCB, B[a]P, and TBT modulate expression of Tj-AhR and Tj-ARNT genes in the putative AhR-CYP signaling pathway. PMID:25216468

Kim, Bo-Mi; Rhee, Jae-Sung; Hwang, Un-Ki; Seo, Jung Soo; Shin, Kyung-Hoon; Lee, Jae-Seong

2015-02-01

318

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

PubMed

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

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

2014-06-01

319

Early winter mesozooplankton of the coastal south-eastern Barents Sea  

NASA Astrophysics Data System (ADS)

The south-eastern Barents Sea (Pechora Sea) is a little studied region of the Russian Arctic. We investigated mesozooplankton community of this area in early winter period for the first time. The study was based on collections performed with a Juday net (168 ?m) in November 2010. Three types of stations differing in mesozooplankton composition and abundance were revealed by non-metric multidimensional scaling analyses. Taxa richness and diversity of the mesozooplankton were high. The total abundance and biomass varied from 931 to 4360 individuals m-3 and from 4.0 to 64.2 mg dry mass m-3, respectively. Maximum density of mesozooplankton was located in the hydrographical frontal zone where cold and warm waters interacted. Copepods dominated in terms of the total abundance. Abundances of major taxa were strongly correlated with environmental variables, of which temperature, salinity and depth were the most important. Previous studies showed that many mesozooplankton are in a dormant state during the Arctic winter from October to April. However, our investigation found young copepodites to be present for many of the common copepod species, which suggests successful reproduction of some opportunistic taxa (Pseudocalanus, Acartia, Temora, Oithona) and that the small copepod community was in an active phase. The main factor influencing possible development of the copepods in the south-eastern Barents Sea was river run-off which supplied plankton with detritus and suspended organic matter.

Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

2015-01-01

320

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

NASA Astrophysics Data System (ADS)

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

Kumar, Ram; Ramakrishna Rao, T.

2003-11-01

321

Bioaccumulation of polonium-210 in marine copepods  

Microsoft Academic Search

Po, a naturally occurring radioisotope that is ubiquitous in seawater, is especially enriched in proteinaceous tissues of marine organisms and may therefore be useful as a tracer of organic carbon flux in marine systems. Due in part to its biomagnification in marine food chains, 210 Po provides the largest radiation dose to any organism under natural conditions. To better understand

Gillian M. Stewart; Nicholas S. Fisher

2003-01-01

322

The Copepods of the Mississippi Delta region  

E-print Network

with the method of Clarke and Bumpus (1950) at a swimming pool. It was found that approximately 4. 6 liters of water were filtered for every turn of the small propeller within the sampler. This factor was nearly identical in the two instruments generally used... covered with short hairs. The right ventral process on the urosome that is observed from a dorsal view is spine-like and small. These two characteristics distinguish the species from E. marina for in the latter the urosome is smooth and the right...

Gonzalez, Juan Gerardo

1957-01-01

323

Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review  

PubMed Central

Abstract The studies on marine copepods of Costa Rica started in the 1990’s and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance of the inland copepod fauna of Costa Rica requires more detailed surveys.

Morales-Ramírez, Álvaro; Suárez-Morales, Eduardo; Corrales-Ugalde, Marco; Garrote, Octavio Esquivel

2014-01-01

324

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

PubMed Central

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

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

2010-01-01

325

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

PubMed

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

Khandeparker, Lidita; Anil, Arga Chandrashekar

2013-09-01

326

Predatory Promesostoma species (Plathelminthes, Rhabdocoela) in the Wadden Sea  

NASA Astrophysics Data System (ADS)

Laboratory experiments were performed on the food ecology of four congeneric species of free-living plathelminths, Promesostoma caligulatum, P. marmoratum, P. rostratum, and P. meixneri, all inhabiting an intertidal sandflat near the island of Sylt (North Sea). Their prey spectrum is within the microcrustaceans: P. caligulatum preferred ostracods, while the other three species favoured copepods, with species-specific differences for copepod species and size classes. Daily consumption of prey species varied with the size of both the predator and the prey. On average, P. marmoratum consumed 0.76 Harpacticus flexus per day while this rate decreased to 0.06 in P. meixneri, the smallest predator. When these Promesostoma species were fed with Tachidius discipes, a smaller prey species, their predation rates were about 25% higher. While the larger predators preferred the larger harpacticoids as prey, the small P. meixneri preferred small cyclopoids over larger harpacticoids. In terms of biomass, P. marmoratum's mean consumption of T. discipes per day was about half the predator's own weight. This average varied with prey density and temperature. A comparison of these consumption rates with the field densities of the predators and their prey shows that the plathelminth predators may consume as much as 10% per day of their copepod prey populations, thus strongly influencing these prey populations on these sandflats. The predation pressure of P. caligulatum on ostracods was about 1% per day of the prey population. Since ostracods usually have fewer generations per year, the total effect on the population dynamics may be similar to that on copepods. Therefore, nocturnal swimming of copepods in the water column may be interpreted as an attempt to escape plathelminth predators.

Menn, Iris; Armonies, Werner

1999-06-01

327

Dispersion and feeding of larval herring ( Clupea harengus L.) in the Moray Firth during September 1985  

NASA Astrophysics Data System (ADS)

A plume of herring larvae dispersing from a spawning site at Clythness in the Moray Firth (northern Scotland) was surveyed during early September 1985. Several cohorts of larvae were evident from the length distributions, and these were arranged in order of increasing length (age) towards the south-west. The spacing of cohort centres indicated a drift rate of 1-2 km day -1. Calanoid copepod nauplii constituted the major proportion of the diet of larvae <10 mm sampled during the study. Cyclopoid copepod nauplii and gastropod veligers were not found in the diet although they were present in the water. The distribution of nauplii in the region was inversely correlated with the concentration of phytoplankton chlorophyll, and nauplii concentrations were above average in the vicinity of the herring spawning site. The drift trajectory of the herring larvae took them towards an area of high copepodite and adult copepod concentration—items which formed an increasing part of the diet of larger (older) larvae.

Heath, M.; Leaver, M.; Matthews, A.; Nicoll, N.

1989-06-01

328

Effects of inorganic turbidity and reservoir floods on the feeding and population dynamics of Cladoceran zooplankton  

SciTech Connect

Clearance rates of {sup 32}P-labeled yeast cell tracer particles and gravimetric seston analysis were used to estimate in situ seston ingestion rates of Daphnia parvula and Bosmina along the seston gradient in Tuttle Creek Reservoir, near Manhattan, Kansas. An ingestion rate depression occurred for both species at the highest seston concentration. The smallest animals, Bosmina, had a lower incipient limiting concentration and exhibited a stronger ingestion rate depression. The fecundity and abundance of Daphnia parvula, grown in enclosures along the seston gradient prior to the ingestion rate measurements, were highest at the river inflow region. Reservoir Bosmina, however, were least abundant and had the lowest fecundity at the river inflow region. The abundance of Bosmina, calanoid copepods, and cyclopoid copepods were lower following large storm inflows in the late spring of 1983 and 1984, while the abundance of Diaphanosoma and Moina were similar. Both open reservoir and in situ enclosure populations of Daphnia pulex were reduced following the storm inflow, while only enclosure populations of Daphnia parvula were lower. Diaphanosoma and calanoid copepods dominated the zooplankton during sampling from spring through fall 1984, particularly in midsummer when temperatures were greater than 25{degree}C. Daphnids dominated numerically during the fall baseflow period.

Shuman, J.R.

1988-01-01

329

Zooplankton distribution in the western Arctic during summer 2002: Hydrographic habitats and implications for food chain dynamics  

NASA Astrophysics Data System (ADS)

Global warming is presently a widely accepted phenomenon with a broad range of anticipated impacts on marine ecosystems. Alterations in temperature, circulation and ice cover in Arctic seas may result in changes in food chain dynamics, beginning with planktonic processes. As part of the Shelf-Basin Interactions (SBI) program, we conducted zooplankton surveys during summer 2002 to assess the biomass, distribution and abundance of copepods and other pelagic zooplankton over the Chukchi and Beaufort shelves, slope regions and the adjacent Canada Basin. The motivation for our fieldwork was the question, "Will global change, particularly warming, result in more large-sized zooplankton which support a pelagic food web of fish, birds, and certain mammals over the Chukchi and Beaufort shelves or in more smaller-sized zooplankton which will diminish the fish, birds and mammals and favor sedentary benthic organisms?" The objectives of the present study were 1) to census the regional zooplankton community and establish a baseline for comparisons with historical and future studies and 2) to determine whether large-bodied copepods associated with deep waters of the Bering Sea or the Canada Basin were transported to the shelves in sufficient numbers to modify the food web in a region where smaller copepods often dominate the zooplankton numerically. Spatial distributions of zooplankton communities were clearly associated with hydrographic habitats determined by the chemical, physical and biological characteristics of the upper water layer. Smaller taxa dominated the shelf communities while offshore zooplankton assemblages were characterized by large-bodied copepods. The mesozooplankton community was numerically dominated by copepod nauplii and small-bodied juveniles, including Pseudocalanus spp. and Oithona similis. We observed very few large-bodied copepods from the Bering Sea. However, much of the shelf region surveyed included relatively numerous Calanus glacialis juveniles and adults, suggesting that these copepods were advected onto the shelf and possibly reproducing there. Juvenile stages of the large-bodied copepod Calanus hyperboreus were found in relative abundance on the Chukchi shelf in the vicinity of Hanna Canyon. These observations suggest that large-bodied, deep-water species from the basin are advected onto the Chukchi Shelf where they may impact the fate of shelf-derived primary production and alter the food webs of the shelves. Regional comparisons of abundances of selected taxa enumerated in the present study with sample data from the early 1950s suggested that some taxa were more abundant in the SBI region in 2002 than ca. 50 years ago. Long-term changes in planktonic populations are expected to have significant implications for shelf-basin exchange of biogenic material in the Chukchi and Beaufort Seas and the adjacent Arctic Basin.

Lane, Peter V. Z.; Llinás, Leopoldo; Smith, Sharon L.; Pilz, Dora

330

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

PubMed

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

Silva, W M; Matsumura-Tundisi, T

2005-08-01

331

Community structure of mesozooplankton in coastal waters of Sundarban mangrove wetland, India: A multivariate approach  

NASA Astrophysics Data System (ADS)

Spatial and temporal distribution of community structure and seasonal distribution of mesozooplankton (MZ; 20-200 ?m) in the context of environmental parameters were studied in the coastal waters of Indian Sundarban wetland formed at the confluence of Hugli (Ganges) River estuary, India. The work has been aimed for better understanding of its ecological characteristics in terms of the most dominant mesozooplankton group in a tropical mesomacrotidal setting. Samples were collected from four sampling sites of different hydrodynamic set up using a ring trawl net (Hydro-Bios No. 438 700, mesh size 200 ?m) equipped with a calibrated flowmeter and both water and plankton samples were analyzed by standard methods. Distribution of MZ showed bimodality with two peak periods, primary peak during April coinciding with maximum number of copepod species (974 ind. m- 3) and the secondary one during August. Copepod was the most dominant taxon where the calanoids formed bulk of the biomass representing 33 species of 7 genera, while cyclopoids formed the next dominant group comprising 4 species of 3 genera followed by 4 monogeneric harpacticoid species. Results of correlation matrix revealed that two copepod families Acartiidae and Pseudodiaptomidae maintain negative relationship with other six families indicating that they form a group by themselves. Results of multiple regression analysis reveal that salinity, chlorophyll-a and transparency are the potential hydrological factors in the distribution and existence of the dominant copepods and total chaetognaths. An overall high diversity index values (max. 3.21) was associated with high richness index (4.39) and high evenness index (0.96) at the site of the mouth of the estuary. In terms of feeding guild, the herbivore copepods were dominant followed by omnivores. Cluster analysis confirmed an overall dominance of the calanoid copepod Bestiolina similis as a solitary group for all the sites. The chaetognath Sagitta bedoti was perennial in distribution where the contribution of juvenile form (recognized as Stage I) was dominant. Among the other MZ, hydromedusae, ctenophore, sergestid and mysid were also encountered contributing insignificant part of the total density. A long-term decadal change in copepod community was pronounced which might be due to climate-induced environmental changes which also modulate the physicochemical characteristics of water.

Bhattacharya, Bhaskar Deb; Hwang, Jiang-Shiou; Sarkar, Santosh Kumar; Rakhsit, Dibyendu; K, Murugan; Tseng, Li-Chun

2015-01-01

332

Restoration impact of an uncontrolled phosphogypsum dump site on the seasonal distribution of abiotic variables, phytoplankton and zooplankton along the near shore of the south-western Mediterranean coast.  

PubMed

'In connection with the Taparura Project, we studied the distribution of phytoplankton and zooplankton communities in relation to environmental variables at 18 stations sampled during four coastal cruises conducted between October 2009 and July 2010 on the north coast of Sfax (Tunisia, western Mediterranean Sea). The inshore location was largely dominated by diatoms (66 %) represented essentially by members of the genera Navicula, Grammatophora, and Licmophora. Dinophyceae were numerically the second largest group and showed an enhanced species richness. Cyanobacteriae developed in association with an important proliferation of colonial Trichodesmium erythraeum, contributing 39.4 % of total phytoplankton abundances. The results suggest that phytoplankters are generally adapted to specific environmental conditions. Copepods were the most abundant zooplankton group (82 %) of total zooplankton. A total of 21 copepod species were identified in all stations, with an overwhelming abundance of Oithona similis in autumn and summer, Euterpina acutifrons in winter, and Oncaea conifera in spring. The phosphogypsum restoration had been acutely necessary allowing dominant zooplankton species to exploit a wide range of food resources including phytoplankton and thus improving water quality. PMID:23149925

Rekik, Amira; Maalej, Sami; Ayadi, Habib; Aleya, Lotfi

2013-06-01

333

Predation impact of carnivorous macrozooplankton in the vicinity of the Prince Edward Island archipelago (Southern Ocean) in austral autumn 1998  

NASA Astrophysics Data System (ADS)

The composition, biomass, feeding and predation impact of carnivorous macrozooplankton (>2 cm) on mesozooplankton (0.2-2 cm) in the sub-Antarctic waters of the southwest Indian Ocean were investigated at 19 stations in austral autumn (April/May) 1998. Zooplankton abundances and biomass ranged from 6.9 to 95.2 ind m -3 and between 1.8 and 18.1 mg Dwt m -3, respectively. Throughout the investigation, mesozooplankton comprising mainly copepods numerically and by biomass dominated net samples. Among the copepods, Calanus simillimus, Clausocalanus brevipes, Ctenocalanus vanus, and Oithona spp. dominated. The carnivore component of the macrozooplankton consisted mainly of five groups: decapods, amphipods, chaetognaths, euphausiids and gelatinous zooplankton. Among these, chaetognaths ( Eukrohnia hamata and Sagitta gazellae) and euphausiids ( Nematoscelis megalops and Euphausia longirostris) were the most prominent. Collectively, the carnivorous macrozooplankton comprised between 11% and 72% of total zooplankton biomass. Total predation impact of the carnivorous macrozooplankton varied considerably but generally accounted for <5% (range 0.7-44%) of the total mesozooplankton standing stock. Tentative calculations suggest that carnivorous macrozooplankton may contribute, via vertical migrations and production of fast sinking faecal pellets, to a downward flux of carbon equivalent to up to 9% of the total mesozooplankton stock per day within the Antarctic Polar Frontal Zone. As a consequence, carnivorous macrozooplankton may increase the localised efficiency of the biological pump.

Froneman, P. W.; Pakhomov, E. A.; Gurney, L. J.; Hunt, B. P. V.

334

Scaling-up anti-predator phenotypic responses of prey: impacts over multiple generations in a complex aquatic community  

PubMed Central

Non-consumptive effects (NCEs) of predators owing to induced changes in prey traits are predicted to influence the structure of ecological communities. However, evidence of the importance of NCEs is limited primarily to simple systems (e.g. two to four species) over relatively short periods (e.g. less than one generation). We examined the NCEs of a fish predator, arising from phenotypic plasticity in zooplankton prey traits, over multiple generations of a diverse zooplankton community. The presence of fish, caged to remove consumptive effects, strongly influenced zooplankton community structure, through both direct and indirect NCE pathways, altering the abundance of many taxa by magnitudes as large as 3 to 10-fold. Presence of fish affected different species of cladocerans and copepods both positively and negatively. A particularly striking result was the reversal of dominance in copepod taxa: presence of fish reduced the ratio of calanoids to cyclopoids from 6.3 to 0.43. Further, the NCE of fish had a strong negative trophic cascade to zooplankton resources (phytoplankton). To our knowledge, this is the first experiment to show that NCEs can influence the abundance of multiple prey species over time spans of multiple prey generations. Our findings demonstrate that adaptive phenotypic plasticity of individuals can scale-up to affect the structure of ecological communities. PMID:21593036

Peacor, Scott D.; Pangle, Kevin L.; Schiesari, Luis; Werner, Earl E.

2012-01-01

335

Effects of alewife predation on zooplankton populations in Lake Michigan  

USGS Publications Warehouse

The zooplankton populations in southeastern Lake Michigan underwent striking, size-related changes between 1954 and 1966. Forms that decline sharply were the largest cladocerans (Leptodora kindtii, Daphnia galeata, and D. retrocurva), the largest calanoid copepods (Limnocalanus macrurus, Epischura lacustris, and Diaptomus sicilis), and the largest cyclopoid copepod (Mesocyclops edax). Two of these, D. galeata and M. edax (both abundant in 1954), became extremely rare. Certain medium-sized or small species increased in numbers: Daphnia longiremis, Holopedium gibberum, Polyphemus pediculus, Bosmina longirostris, Bosmina coregoni, Ceriodaphnia sp., Cyclops bicuspidatus, Cyclops vernalis, and Diaptomus ashlandi. Evidence is strong that the changes were due to selective predation by alewives. The alewife was uncommon in southeastern Lake Michigan in 1954 but had increased to enormous proportions by 1966; there was a massive dieoff in spring 1967, and abundance remained relatively low in 1968. The composition of zooplankton populations in 1968 generally had shifted back toward that of 1954, although D. galeata and M. edax remained rare. The average size, and size at onset of maturity, of D. retrocurva decreased noticeably between 1954 and 1966 but increased between 1966 and 1968.

Wells, LaRue

1970-01-01

336

Phylogenetic Information Content of Copepoda Ribosomal DNA Repeat Units: ITS1 and ITS2 Impact  

PubMed Central

The utility of various regions of the ribosomal repeat unit for phylogenetic analysis was examined in 16 species representing four families, nine genera, and two orders of the subclass Copepoda (Crustacea). Fragments approximately 2000?bp in length containing the ribosomal DNA (rDNA) 18S and 28S gene fragments, the 5.8S gene, and the internal transcribed spacer regions I and II (ITS1 and ITS2) were amplified and analyzed. The DAMBE (Data Analysis in Molecular Biology and Evolution) software was used to analyze the saturation of nucleotide substitutions; this test revealed the suitability of both the 28S gene fragment and the ITS1/ITS2 rDNA regions for the reconstruction of phylogenetic trees. Distance (minimum evolution) and probabilistic (maximum likelihood, Bayesian) analyses of the data revealed that the 28S rDNA and the ITS1 and ITS2 regions are informative markers for inferring phylogenetic relationships among families of copepods and within the Cyclopidae family and associated genera. Split-graph analysis of concatenated ITS1/ITS2 rDNA regions of cyclopoid copepods suggested that the Mesocyclops, Thermocyclops, and Macrocyclops genera share complex evolutionary relationships. This study revealed that the ITS1 and ITS2 regions potentially represent different phylogenetic signals. PMID:25215300

Zagoskin, Maxim V.; Lazareva, Valentina I.; Grishanin, Andrey K.; Mukha, Dmitry V.

2014-01-01

337

Feeding ecology of lake whitefish larvae in eastern Lake Ontario  

USGS Publications Warehouse

We examined the feeding ecology of larval lake whitefish (Coregonus clupeaformis) in Chaumont Bay, Lake Ontario, during April and May 2004-2006. Larvae were collected with towed ichthyoplankton nets offshore and with larval seines along the shoreline. Larval feeding periodicity was examined from collections made at 4-h intervals over one 24-h period in 2005. Inter-annual variation in diet composition (% dry weight) was low, as was spatial variation among collection sites within the bay. Copepods (81.4%), primarily cyclopoids (59.1%), were the primary prey of larvae over the 3-year period. Cladocerans (8.1%; mainly daphnids, 6.7%) and chironomids (7.3%) were the other major prey consumed. Larvae did not exhibit a preference for any specific prey taxa. Food consumption of lake whitefish larvae was significantly lower at night (i.e., 2400 and 0400 h). Substantial variation in diet composition occurred over the 24-h diel study. For the 24-h period, copepods were the major prey consumed (50.4%) and their contribution in the diet ranged from 29.3% (0400 h) to 85.9% (1200 h). Chironomids made up 33.4% of the diel diet, ranging from 8.0% (0800 h) to 69.9% (0400 h). Diel variation in the diet composition of lake whitefish larvae may require samples taken at several intervals over a 24-h period to gain adequate representation of their feeding ecology.

Johnson, James H.; McKenna, James E.; Chalupnicki, Marc A.; Wallbridge, Tim; Chiavelli, Rich

2009-01-01

338

Population Consequences of Fipronil and Degradates to Copepods at  

E-print Network

. F E R R Y Department of Environmental Health Sciences, Norman J. Arnold School of Public Health and degradates of the phenylpyrazole insecticide fipronil. Survival, development rates, sex ratio change threshold density is of highest value to management. As articulated in two recent papers in this Journal (1

Coull, Bruce C.

339

Development of a Halotolerant Community in the St. Lucia Estuary (South Africa) during a Hypersaline Phase  

PubMed Central

Background The St. Lucia Estuary, Africa's largest estuarine lake, is currently experiencing unprecedented freshwater deprivation which has resulted in a northward gradient of drought effects, with hypersaline conditions in its northern lakes. Methodology/Principal Findings This study documents the changes that occurred in the biotic communities at False Bay from May 2010 to June 2011, in order to better understand ecosystem functioning in hypersaline habitats. Few zooplankton taxa were able to withstand the harsh environmental conditions during 2010. These were the flatworm Macrostomum sp., the harpacticoid copepod Cletocamptus confluens, the cyclopoid copepod Apocyclops cf. dengizicus and the ciliate Fabrea cf. salina. In addition to their exceptional salinity tolerance, they were involved in a remarkably simple food web. In June 2009, a bloom of an orange-pigmented cyanobacterium (Cyanothece sp.) was recorded in False Bay and persisted uninterruptedly for 18 months. Stable isotope analysis suggests that this cyanobacterium was the main prey item of F. cf. salina. This ciliate was then consumed by A. cf. dengizicus, which in turn was presumably consumed by flamingos as they flocked in the area when the copepods attained swarming densities. On the shore, cyanobacteria mats contributed to a population explosion of the staphylinid beetle Bledius pilicollis. Although zooplankton disappeared once salinities exceeded 130, many taxa are capable of producing spores or resting cysts to bridge harsh periods. The hypersaline community was disrupted by heavy summer rains in 2011, which alleviated drought conditions and resulted in a sharp increase in zooplankton stock and diversity. Conclusions/Significance Despite the current freshwater deprivation crisis, the False Bay region has shown to be resilient, harboring a unique biodiversity with species that are capable of enduring harsh environmental conditions. However, further freshwater deprivation may extend beyond the physiological thresholds of this community, as well as other unique biodiversity components which this system sustains. PMID:22238676

Carrasco, Nicola K.; Perissinotto, Renzo

2012-01-01

340

Latitudinal and taxonomic patterns in the feeding ecologies of fish larvae: A literature synthesis  

NASA Astrophysics Data System (ADS)

The longtime focus on factors that influence the survival of marine fish larvae has yielded an extensive number of studies on larval fish diets and feeding success. In light of a recent increase in such studies within lower latitudes, results from the peer-reviewed literature were synthesized to examine both latitudinal and taxonomic differences in several trophic-related categories, including feeding incidence, trophic niche breadth, ontogenetic diet shifts, dominant prey types, diet broadness, and larval piscivory. A total of 204 investigations (taxon-article combinations) contained suitable results for at least one of these categories. Feeding incidences (proportions of larvae containing food) were significantly higher in lower latitudes with all taxa combined, as well as only within the order Perciformes. Feeding incidences also differed among orders, with Perciformes and Scorpaeniformes having the highest values. The number of larval taxa exhibiting a significantly increasing niche breadth (SD of the log of prey sizes) with larval size decreased toward lower latitudes, with some taxa in lower latitudes exhibiting a decrease in niche breadth with size. The frequency of exhibiting ontogenetic diets shifts decreased with decreasing latitude, as did relative diet broadness (a function of prey types). The most common dominant prey types in the diets of higher latitude larvae were nauplii and calanoid copepods, with cyclopoids being rare in higher latitudes. Dominant prey types in lower latitudes were more diverse, with nauplii, calanoids, and cyclopoids being equally important. Appendicularians increased in importance with decreasing latitude, and one of the clearest latitudinal distinctions was the display of larval piscivory (almost exclusively by scombroid taxa), which was highly concentrated in lower latitudes. Overall, the latitudinal differences observed for multiple trophic-related factors highlight inherent distinctions in larval fish feeding ecologies, likely reflecting differences in the overall structure of planktonic food webs over large latitudinal gradients.

Llopiz, Joel K.

2013-01-01

341

Temporal changes in the sensitivity of coastal Antarctic zooplankton communities to diesel fuel: a comparison between single- and multi-species toxicity tests.  

PubMed

Despite increasing human activity and risk of fuel spills in Antarctica, little is known about the impact of fuel on Antarctic marine fauna. The authors performed both single- and multi-species (whole community) acute toxicity tests to assess the sensitivity of an Antarctic coastal zooplankton community to the water-accommodated fraction of Special Antarctic Blend diesel. Single-species tests using abundant copepods Oncaea curvata, Oithona similis, and Stephos longipes allowed comparisons of sensitivity of key taxa and of sensitivity estimates obtained from traditional single-species and more novel multi-species tests. Special Antarctic Blend diesel caused significant mortality and species compositional change in the zooplankton community within 4 d to 7 d. The sensitivity of the community also increased across the summer sampling period, with decreasing 7-d median lethal concentration (LC50) values for total petroleum hydrocarbons (TPH): 1091 µg TPH/L in early January 2011, 353 µg TPH/L in mid January 2011, and 186 µg TPH/L in early February 2011. Copepods showed similar sensitivities to Special Antarctic Blend diesel in single-species tests (7-d LC50s: O. curvata, 158 µg TPH/L; O. similis, 176 µg TPH/L; S. longipes, 188 µg TPH/L). The combined use of single- and multi-species toxicity tests is a holistic approach to assessing the sensitivity of key species and the interactions and interdependence between species, enabling a broader understanding of the effects of fuel exposure on the whole zooplankton community. PMID:24590679

Payne, Sarah J; King, Catherine K; Zamora, Lara Marcus; Virtue, Patti

2014-04-01

342

How does mesh-size selection reshape the description of zooplankton community structure in coastal lakes?  

NASA Astrophysics Data System (ADS)

To provide evidence of the inadequacy of using conventional sampling methods to study mesozooplankton community structure in confined environments, samples from a Mediterranean meromictic coastal lake were taken using 80-?m and 200-?m mesh nets towed at three different depths (0-18 m). Mesh size significantly affected the description of the community structure of the collected zooplankton. The 80-?m-mesh catch revealed for the first time in such an environment the overwhelming abundance of the copepod species Oithona brevicornis, as two orders of magnitude greater than recorded for the 200-?m-mesh catch. The other dominant species were Paracartia latisetosa and Pseudodiaptomus marinus, which were more efficiently sampled with the 200-?m mesh. These showed a summer abundance peak for P. latisetosa near the surface layer, and for P. marinus in the deepest stratum, close to the anoxic layer. Copepod nauplii and bivalve larvae were more efficiently caught with the 80-?m-mesh, and accounted for most of the zooplankton in winter, and showed the highest loss percentage of abundance between the two mesh-size catches. The differences in the assemblages reflect different diversity patterns, with peaks in summer and winter for the communities collected with the 80-?m-mesh and 200-?m-mesh, respectively. These findings imply the need for the development of a commonly used sampling method with paired nets, to correctly take into account both the large and small fractions of the mesozooplankton in the study of closed and semi-enclosed coastal environments, and to obtain data that can be better compared across studies.

Pansera, Marco; Granata, Antonia; Guglielmo, Letterio; Minutoli, Roberta; Zagami, Giacomo; Brugnano, Cinzia

2014-12-01

343

The distribution and vertical flux of fecal pellets from large zooplankton in Monterey bay and coastal California  

NASA Astrophysics Data System (ADS)

We sampled zooplankton and fecal pellets in the upper 200 m of Monterey Bay and nearby coastal regions in California, USA. On several occasions, we observed high concentrations of large pellets that appeared to be produced during night-time by dielly migrating euphausiids. High concentrations of pellets were found in near-surface waters only when euphausiids co-occurred with high concentrations of large (>10 ?m) phytoplankton. Peak concentrations of pellets at mid-depth (100 or 150 m) during the day were consistent with the calculated sinking speeds of pellets produced near the surface at night. At these high flux locations (HI group), pellet concentrations declined below mid-depth. In contrast, at locations where the phytoplankton assemblage was dominated by small phytoplankton cells (<10 ?m), pellet production and flux were low (LO group) whether or not euphausiid populations were high. Protozooplankton concentrations did not affect this pattern. We concluded that the day and night differences in pellet concentration and flux in the HI profiles were mostly due to sinking of dielly-pulsed inputs in the surface layer, and that small zooplankton (Oithona, Oncaea), heterotrophic dinoflagellates, and bacterial activity probably caused some pellet degradation or consumption below 100 m. We estimated that consumption of sinking pellets by large copepods was insignificant. High fluxes of pellets were episodic because they required both high concentrations of large phytoplankton and large stocks of euphausiids. Under these conditions, flux events overwhelmed retention mechanisms, resulting in large exports of organic matter from the upper 200 m.

Dagg, Michael J.; Jackson, George A.; Checkley, David M.

2014-12-01

344

Sea ice and the onshore offshore gradient in pre-winter zooplankton assemblages in southeastern Beaufort Sea  

NASA Astrophysics Data System (ADS)

Zooplankton communities were studied in southeastern Beaufort Sea (Arctic Ocean) in September-October 2002. Cluster analysis and non-metric multidimensional scaling revealed three distinct mesozooplankton assemblages. A neritic assemblage occurred on the Mackenzie Shelf and in Franklin Bay, while distinct off-shelf assemblages prevailed in the Cape Bathurst Polynya and on the Beaufort Slope respectively. Over 95% of the mesozooplankton was comprised of eight copepod taxa. Pseudocalanus spp. contributed predominantly to the discrimination of the three assemblages and was the only significant indicator of the Shelf assemblage. Oithona similis, Oncaea borealis, Metridia longa and Calanus hyperboreus were indicators of the Polynya assemblage. Cyclopina sp. and Microcalanus pygmaeus were indicative of the overall off-shelf community (Polynya and Slope assemblages). The importance of omnivores and carnivores increased from the shelf to the polynya and the slope. Station depth and duration of reduced ice conditions during summer (< 50% ice concentration) underpinned the distribution of the assemblages ( r2 = 0.71 and 0.45 respectively). The abundance of Pseudocalanus spp. was independent of depth and increased with the duration of reduced ice conditions ( rs = 0.438). The abundance of Cyclopina sp., M. pygmaeus and other indicators of the offshore assemblages followed the opposite trend ( rs = - 0.467 and - 0.5 respectively). Under continued climate warming, a reduction of the ice cover will affect the biogeography of mesozooplankton on and around the Mackenzie Shelf, to the potential advantage of Pseudocalanus spp. and other calanoid herbivores.

Darnis, Gérald; Barber, David G.; Fortier, Louis

2008-12-01

345

Diet overlap in larval lake herring (Coregonus artedi) and bloaters (Coregonus hoyi)  

USGS Publications Warehouse

The food preferences of larval lake herring (Coregonus artedi) and bloater (C.hoyi) were compared in a small mesotrophic lake in southeastern Michigan. Diets of the two were increasingly similar as the experiment progressed until, by the end of 6.5 weeks, they were identical; Schoener's Index of diet overlap averaged 0.35 in the first week and reached 0.96 by the end of the study. In the first few weeks, lake herring ate mostly small cladocerans (Bosmia longirostris) and bloaters ate mostly large cladocerans (Eurycercus lamellatus). Strauss's selection index confirmed that lake herring actively fed on small cladocerans throughout the study and that bloaters relied more on cyclopoid copepods during the early part of the study and shifted to eating small and large cladocerans by the end. Both species had similar growth rates throughout the study and amount of consumed food was identical. The diet similarities of lake herring and bloater larvae could make them competitors for food in the Great Lakes, relieved only by a dissimilarity in hatching times and locations.

Davis, Bruce M.; Todd, Thomas N.

1992-01-01

346

A new species of Halicyclops (Copepoda, Cyclopoida, Cyclopidae) from a lagoon system of the Caribbean coast of Colombia  

PubMed Central

Abstract Plankton samples obtained from the lagoon system Laguna Navío Quebrado, in northern Colombia, yielded male and female specimens of an undescribed cyclopoid copepod of the genus Halicyclops. The new species belongs to the highly diverse and widely distributed thermophilus-complex. It closely resembles Halicyclops clarkei Herbst, 1982 from Louisiana and Halicyclops bowmani Rocha & Iliffe, 1993 from Bermuda. These species share the same armature of P1-P4EXP3, with a 3443 spine formula and the terminal antennary segment with 5 setae. However, Halicyclops gaviriai sp. n. can be separated from both Halicyclops clarkei and Halicyclops bowmani by the morphology of the anal pseudoperculum, the proportions of the fourth antennulary segment, the length of the inner basipodal spine of P1, the P1EXP/inner basipodal spine inner length ratio and the length/width ratio of the caudal rami. This is the third species of Halicyclops recorded from Colombia and the first one described from this country. With the addition of Halicyclops gaviriai sp. n., the number of species of Halicyclops known from the Neotropics increases to 19. The regional diversity of the genus is probably underestimated. PMID:25561852

Suárez-Morales, Eduardo; Fuentes-Reinés, Juan M.

2014-01-01

347

Competition between larval lake herring (Coregonus artedi) and lake whitefish (Coregonus clupeaformis) for zooplankton  

USGS Publications Warehouse

Diet and growth of larval lake herring (Coregonus artedi) and lake whitefish (Coregonus clupeaformis) were compared in mesocosm experiments in a small mesotrophic lake in southeastern Michigan. Fish were sampled from single-species and mixed assemblages in 2-m3 cages for 8 weeks during April and May. Both species initially ate mostly cyclopoid copepodites and small cladocerans (Bosmia spp.). Schoener's index of diet overlap showed considerable overlap (70-90%). Lake whitefish ate Daphnia spp. and adult copepods about 2 weeks earlier than did lake herring, perhaps related to their larger mean mouth gape. Lake whitefish were consistently larger than lake herring until the eighth week, especially in the sympatric treatments. Lake whitefish appeared to have a negative effect on the growth of lake herring, as lake herring in mixed-species treatments were smaller and weighed less than lake herring reared in single-species treatments. The diet similarities of lake whitefish and lake herring larvae could make them competitors for food in the Great Lakes. The greater initial size of lake whitefish could allow them to eat larger prey earlier and thereby limit availability of these prey to lake herring at a crucial period of development.

Davis, Bruce M.; Todd, Thomas N.

1998-01-01

348

Change and recovery of coastal mesozooplankton community structure during the Deepwater Horizon oil spill  

NASA Astrophysics Data System (ADS)

The response of mesozooplankton community structure to the Deepwater Horizon oil spill in the northern Gulf of Mexico was investigated using data from a long-term plankton survey off the coast of Alabama (USA). Environmental conditions observed in the study area during the oil spill (2010) were compared to historical observations (2005–2009), to support the contention that variations observed in zooplankton assemblage structure may be attributed to the oil spill, as opposed to natural climatic or environmental variations. Zooplankton assemblage structure observed during the oil spill period (May–August) in 2010 was then compared to historical observations from the same period (2005–2009). Significant variations were detected in assemblage structure in May and June 2010, but these changes were no longer significant by July 2010. The density of ostracods, cladocerans and echinoderm larvae were responsible for most of the differences observed, but patterns differed depending on taxa and months. Many taxa had higher densities during the oil spill year, including calanoid and cyclopoid copepods, ostracods, bivalve larvae and cladocerans, among others. Although this result is somewhat surprising, it is possible that increased microbial activity related to the infusion of oil carbon may have stimulated secondary production through microbial-zooplankton trophic linkages. Overall, results suggest that, although changes in zooplankton community composition were observed during the oil spill, variations were weak and recovery was rapid.

Carassou, L.; Hernandez, F. J.; Graham, W. M.

2014-12-01

349

The structure of the benthic macrofaunal assemblages and sediments characteristics of the Paraguaçu estuarine system, NE, Brazil  

NASA Astrophysics Data System (ADS)

The structure of the benthic macrofaunal assemblages of the estuarine portion of Paraguaçu River, NE, Brazil, and its relationship with surface sediment characteristics (trace metals, PAHs, nutrients and grain size) and physical variables were investigated at ten stations on two contrasting occasions, summer (dry season) and winter (rainy season). A total of 1258 individuals (632 in winter and 626 in summer) and 62 taxa representing polychaetes, crustaceans, bivalves, echinoderms, bryozoans, sponges, cnidarians and cephalochordates were collected. Benthic assemblages in the upper estuary were unlike those in the lower estuary and a clear substitution of benthic taxa along the estuary was observed. Macrofaunal invertebrates in the low salinity region, composed of coarse sediments, were dominated by tellinids, venerids (bivalves), cirolanids (isopods), cyclopoids (copepods), and nereidids (polychaetes). While the high salinity region, composed of fine sediments, were dominated by nuculids (bivalves), cirratulids (polychaetes), and by amphiurids (ophiuroids). The Paraguaçu estuarine system is not severely affected by anthropogenic activities. In the great majority of the study sites, concentrations of trace metals and PAHs in the sediments were near background values. Nutrients values were also low. We formulated new models of taxon distribution and suggested detailed studies on the effects of salinity variation and studies using functional approaches to better understand the processes causing the spatial patterns in tropical estuarine benthic assemblages.

Barros, Francisco; Hatje, Vanessa; Figueiredo, Maria Betânia; Magalhães, Wagner Ferreira; Dórea, Haroldo Silveira; Emídio, Elissandro Soares

2008-07-01

350

Postcyclic transmission and its effect on the distribution of Paulisentis missouriensis (Acanthocephala) in the definitive host Semotilus atromaculatus.  

PubMed

The relationship of fish age class to parasitism by Paulisentis missouriensis was determined by sampling at least 29 creek chubs, Semotilus atromaculatus, from Easly Creek, Richardson County, Nebraska, every month from February 1996 to March 1997. In general, mean abundance and prevalence of the acanthocephalans increased with the age or length of chubs. It is unlikely that this distribution is explained by increased consumption of intermediate hosts by older, larger fish or by predatory fish acquiring parasites from paratenic hosts. The intermediate host for P. missouriensis is the cyclopoid copepod Acanthocyclops robustus, and creek chubs do not consume more microscopic crustaceans as they age or grow. Instead, the percentage of fish in the diet of creek chubs increases. Furthermore, P. missouriensis apparently does not use paratenic hosts. In laboratory infections, P. missouriensis survived predation of its original definitive host and transferred to the predator. Postcyclically transmitted P. missouriensis survived at least 14 days in the intestine of creek chubs, where they localized around the first flexure beyond the stomach. All stages of development of both sexes were transferred successfully. Postcyclic transmission is a plausible explanation, in some cases, for the greater worm burden frequently observed in older, larger hosts and for the occurrence in top carnivores of parasites not known to have paratenic hosts. This method of transmission appears to result in distribution of acanthocephalans to groups of animals that otherwise would be inaccessible. PMID:15040674

McCormick, Aaron L; Nickol, Brent B

2004-02-01

351

Condition of larval and early juvenile Japanese temperate bass Lateolabrax japonicus related to spatial distribution and feeding in the Chikugo estuarine nursery ground in the Ariake Bay, Japan  

NASA Astrophysics Data System (ADS)

The present study investigates feeding and condition of larval and juvenile Japanese temperate bass Lateolabrax japonicus in relation to spatial distribution in the Chikugo estuary (Japan). Larvae were collected in a wide area covering the nursery grounds of the species in 2002 and 2003. Food habits of the fish were analysed by examining their gut contents. Fish condition was evaluated by using morphometric (the length-weight relationship and condition factor) and biochemical (the RNA:DNA ratio and other nucleic acid based parameters) indices and growth rates. The nucleic-acid contents in individually frozen larvae and juveniles were quantified by standard fluorometric methods. Two distinct feeding patterns, determined by the distribution of prey copepods, were identified. The first pattern showed dependence on the calanoid copepod Sinocalanus sinensis, which was the single dominant prey in low-saline upper river areas. The second pattern involved a multi-specific dietary habit mainly dominated by Acartia omorii, Oithona davisae, and Paracalanus parvus. As in the gut contents analyses, two different sets of values were observed for RNA, DNA, total protein, growth rates and for all the nucleic acid-based indices: one for the high-saline downstream areas and a second for the low-saline upstream areas, which was significantly higher than the first. The proportion of starving fish was lower upstream than downstream. Values of the allometric coefficient ( b) and the condition factor ( K) obtained from the length-weight relationships increased gradually from the sea to the upper river. Clearly, fish in the upper river had a better condition than those in the lower estuary. RNA:DNA ratios correlated positively with temperature and negatively with salinity. We hypothesise that by migration to the better foraging grounds of the upper estuary (with higher prey biomass, elevated temperature and reduced salinity), the fish reduce early mortality and attain a better condition. We conclude that utilisation of the copepod S. sinensis in the upstream nursery grounds is one of the key early survival strategies in Japanese temperate bass in the Chikugo estuary.

Islam, Md. Shahidul; Hibino, Manabu; Nakayama, Kouji; Tanaka, Masaru

2006-02-01

352

Plankton dynamics due to rainfall, eutrophication, dilution, grazing and assimilation in an urbanized coastal lagoon  

NASA Astrophysics Data System (ADS)

After a prolonged summer dry period, the effects of a distinctive and continuing rainfall on the nutrients and plankton of an urban coastal lagoon were investigated over 2 months. The lagoon filled up over 5 weeks from <10% of its maximum volume until it broke open to the sea. Nutrients (ammonia and oxidised nitrogen) significantly increased the day after initial rainfall, before returning to pre-rainfall conditions within 5 days. Phytoplankton biomass grew 10 fold within a week after initial rainfall in the 25-30 °C water and declined to near initial levels 2 weeks later. The assemblage of phytoplankton and zooplankton changed dramatically after 1 day and again by 6 days later, gradually returning to the original community by 2 weeks after the initial rainfall. Zooplankton responded within a day with a two fold increase in the adult stages of the calanoid copepod Oithona sp., followed a week later by nauplii and adult Acartia bispinosa. The influx of adult Oithona indicates resting populations that were previously under sampled by our plankton net. The plankton community returned to the initial state by 2 weeks, to being dominated by a centric diatom and A. bispinosa after 5 weeks. Dilution of the lagoon reached a maximum of 0.25 d -1, while growth rates of the phytoplankton population reached a maximum of 1 d -1, and A. bispinosa nauplii growth of 2.5 d -1. Declines in chlorophyll biomass from the maximum 10 ?g l -1, at a rate of approximately 10% d -1 are consistent with the modelled uptake by zooplankton. The nutrients from runoff, growth and the influx of new zooplankton into the water column, resulted in a depleted ?13C and ?15N stable isotope signature of A. bispinosa by 2-4 ppt within 1-2 weeks, consistent with diatom growth and the terrestrial supply of depleted nutrients. ?34S of A. bispinosa was enriched by 2 ppt for 1-2 weeks after rainfall, but unlike C and N, returned to pre-rainfall levels by the end of the study period. We suggest that plankton studies in coastal lakes with variable water levels that are not tidally driven, should account for the influence of changes in water levels to help explain data variability.

Rissik, David; Shon, Edward Ho; Newell, Brooke; Baird, Mark E.; Suthers, Iain M.

2009-08-01

353

Endemism of subterranean Diacyclops in Korea and Japan, with descriptions of seven new species of the languidoides-group and redescriptions of D. brevifurcus Ishida, 2006 and D. suoensis Ito, 1954 (Crustacea, Copepoda, Cyclopoida)  

PubMed Central

Abstract Copepods have been poorly studied in subterranean habitats in Korea. Previous records have indicated mostly the presence of species already described from Japan, with very few endemic elements. This commonality has usually been explained by repeated dispersal across the land bridges that connected the two countries several times during the Pleistocene glacial cycles. However, the Korean Peninsula is known for pockets of Cambrian and Ordovician carbonate rocks, with more than 1,000 caves already having been explored. The relative isolation of these carbonate pockets makes for an enormous speciation potential, and the development of a high level of short-range endemism of subterranean copepods should be expected. Representatives of the genus Diacyclops Kiefer, 1927 are here investigated from a range of subterranean habitats in South Korea, with comparative material sampled from central Honshu in Japan. Morphological analyses of microcharacters, many of which are used in cyclopoid taxonomy for the first time herein, reveal high diversity in both countries. No subterranean species is found in common, although the existence of four sibling species pairs in Korea and Japan may be indicative of relatively recent speciation. We describe seven new stygobiotic species, including three from Korea (Diacyclops hanguk sp. n., Diacyclops leeae sp. n., and Diacyclops parasuoensis sp. n.) and four from Japan (Diacyclops hisuta sp. n., Diacyclops ishidai sp. n., Diacyclops parahanguk sp. n., and Diacyclops pseudosuoensis sp. n.). Diacyclops hanguk, Diacyclops parasuoensis, Diacyclops ishidai, and Diacyclops parahanguk are described from newly collected material, while the other three new species are proposed for specimens previously identified as other, widely distributed species. Diacyclops brevifurcus Ishida, 2006 is redescribed from the holotype female, and Diacyclops suoensis Ito, 1954 is redescribed from material newly collected near the ancient Lake Biwa in Japan. This research provides evidence for the importance of subterranean habitats as reservoirs of biodiversity, and also demonstrates the inadequacy of current morphological methods of identifying closely related species of copepods. The disproportionately high diversity discovered around Lake Biwa provides further evidence in support of the hypothesis about the role of ancient lakes as biodiversity pumps for subterranean habitats. A key to the East Asian species of the languidoides-group is provided. PMID:23653520

Karanovic, Tomislav; Grygier, Mark J.; Lee, Wonchoel

2013-01-01

354

Optical-digital measurements of energy reserves in Calanoid copepods: Intersegmental distribution and seasonal patterns  

Microsoft Academic Search

We present a simple optical-digital method to measure visible energy reserves in calanoid CO- pepods. Seasonal patterns (spring-fall) of triacylglycerol energy reserves in Diaptomus sicilis were determined in a hypereutrophic and in a saline prairie lake. In addition to optical measurement of energy reserves, two well-established chemical techniques (microgravirnetric and Iatroscan TLC- FID analyses) were used over the same period.

MICHAEL T. ARTS; MARLENE S. EVANS

1991-01-01

355

Storage lipids of the copepod Calanus finmarchicus from Georges Bank and the Gulf of Maine  

Microsoft Academic Search

Storage lipids of fifth copepodites (C5) of Culanus$nmarchicus from Georges Bank and the Gulf of Maine were quantified from video images and by Iatroscan (thin-layer chromatography with flame-ionization detection, FID). Oil withdrawn from the oil sac by micropipette was pure wax ester (WE); triacylglycerols (TAG) were elsewhere in the body. Video images indicated more WE than could be demonstrated by

Charles B. Miller; Cheryl A. Morgan; Fredrick G. Prahl; Margaret A. Sparrow

1998-01-01

356

Chromatin Diminution Process Regulates rRNA Gene Copy Number in Freshwater Copepods  

PubMed Central

The results of quantitative PCR (qPCR) presented in the paper clearly demonstrate that the sixteen-fold genome reduction inCyclops kolensisduring chromatin diminution (from 15.3 pg to 0.98 pg) results in a dramatic decrease in ribosomal RNA gene copy numbers in the genome of a somatic cell line by more than two orders of magnitude. The results presented allow for the consideration of the chromatin diminution as a mechanism of rDNA copy number regulation. PMID:22649664

Zagoskin, M. V.; Marshak, T. L.; Mukha, D. V.; Grishanin, A. K.

2010-01-01

357

Testing for resistance of pelagic marine copepods to a toxic dinoflagellate  

Microsoft Academic Search

With few exceptions, the evolutionary consequences of harmful algae to grazers in aquatic systems remain unexplored. To examine both the ecological and evolutionary consequences of harmful algae on marine zooplankton, we used a two-fold approach. In the first approach, we examined the life history responses of two geographically separate Acartia hudsonica (Copepoda Calanoida) populations reared on diets containing the toxic

Sean P. Colin; Hans G. Dam

2005-01-01

358

The invasive predator Bythotrephes induces changes in the vertical distribution of native copepods in Lake Michigan  

Microsoft Academic Search

Invasive predators can have large negative effects on native prey populations. The susceptibility of native prey to invasive\\u000a predators may depend on their ability to respond behaviorally to the presence of these non-native predators. In a field survey\\u000a conducted in Lake Michigan over several years, we found that high densities of the invasive predatory cladoceran Bythotrephes were correlated with lower

Paul E. Bourdeau; Kevin L. Pangle; Scott D. Peacor

359

FIPRONIL-INDUCED MALE INFERTILITY IN THE MEIOBENTHIC HARPACTICOID COPEPOD, AMPHIASCUS TENUIREMIS. (R827397)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

360

Acute and sub-lethal response to mercury in Arctic and boreal calanoid copepods.  

PubMed

Acute lethal toxicity, expressed as LC50 values, is a widely used parameter in risk assessment of chemicals, and has been proposed as a tool to assess differences in species sensitivities to chemicals between climatic regions. Arctic Calanus glacialis and boreal Calanus finmarchicus were exposed to mercury (Hg(2+)) under natural environmental conditions including sea temperatures of 2° and 10°C, respectively. Acute lethal toxicity (96 h LC50) and sub-lethal molecular response (GST expression; in this article gene expression is used as a synonym of gene transcription, although it is acknowledged that gene expression is also regulated, e.g., at translation and protein stability level) were studied. The acute lethal toxicity was monitored for 96 h using seven different Hg concentrations. The sub-lethal experiment was set up on the basis of nominal LC50 values for each species using concentrations equivalent to 50, 5 and 0.5% of their 96 h LC50 value. No significant differences were found in acute lethal toxicity between the two species. The sub-lethal molecular response revealed large differences both in response time and the fold induction of GST, where the Arctic species responded both faster and with higher mRNA levels of GST after 48 h exposure. Under the natural exposure conditions applied in the present study, the Arctic species C. glacialis may potentially be more susceptible to mercury exposure on the sub-lethal level. PMID:25036619

Overjordet, Ida Beathe; Altin, Dag; Berg, Torunn; Jenssen, Bjørn Munro; Gabrielsen, Geir Wing; Hansen, Bjørn Henrik

2014-10-01

361

Suitability of cuticular pores and sensilla for harpacticoid copepod species delineation and phylogenetic reconstruction.  

PubMed

Cuticular organs have not been described systematically in harpacticoids until recently, and they haven ever been used as characters for reconstructing phylogenetic relationships in any crustacean group. We survey cuticular pores and sensilla on somites in ten Miraciidae species, belonging to six genera, from Korea, Australia, and Russia. Nine species belong to the subfamily Stenheliinae, while the outgroup belongs to the subfamily Diosaccinae. We aim to compare phylogenetic trees reconstructed for these harpactioids based on: 1) cuticular organs (with 76 characters scored, 71% of them phylogenetically informative); 2) traditionally used macro-morphological characters (66 scored, 77% of them informative);and 3) mtCOI DNA data. All analyses suggest that cuticular organs are useful characters for harpacticoid species delineation, although not as sensitive as some fast-evolving molecular markers. Reconstructed cladograms based on all three datasets show very high bootstrap values for clades representing distinct genera, suggesting that cuticular organs are suitable characters for studying phylogenetic relationships. Bootstrap values for the more basal nodes differ among the different cladograms,as do the sister-group relationships they suggest, indicating that cuticular organs probably have different evolutionary constraints from macro-morphological characters. Cuticular organs could be quite useful in the study of old museum specimens and fossil crustaceans. PMID:25264078

Karanovic, Tomislav; Kim, Kichoon

2014-11-01

362

REPRODUCTIVE AND DEVELOPMENTAL EFFECTS OF ATRAZINE ON THE ESTUARINE MEIOBENTHIC COPEPOD, AMPHIASCUS TENUIREMIS. (R827397)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

363

EFFECT OF HUMIC ACID ON UPTAKE AND TRANSFER OF COPPER FROM MICROBES TO CILIATES TO COPEPODS  

EPA Science Inventory

This research is part of an ongoing project designed to determine the effect of humic acid on the uptake and transfer of metals by marine organisms at the lower end of the food chain. Binding affinities for Cu, Cd, Zn, and Cr to Suwannee River humic acid were determined at variou...

364

Studies on harpacticoid copepod populations of two transects across the south Texas outer continental shelf  

E-print Network

C3 N QJ M tn I cu I I C3 N (3 u3 ICI O n I CQ? 0 e C I- V' 0 Ufd 0 C ( Vl 0 0 ?0 C I- N E L Q o Q 0 I Ql N I Gl I 0 V C L tlJ Ct V C Ql GJ (J (J I. 0- 0 :3 O 0 I/I O C C 'Cl 01 I dJ L + 0 0 E 0 Gl Vl L ( V Gf... C (C ' 04? E E N (3 Pj L - 0 (U\\/ U (3 J 0 I? ( Vj 47 Qt + 0 Cl 0 E I Ql C E. 'I C. 0 4 I- Cl Qt C 0 '(7 Ql C 0 CU Qt 0 3 Ql 4- C O 0 0 C: '0 D Ql F D C Et 4 + Jl 1 3 (7 C: 0 4- 0 U 0 0 C D I...

Venn, Cynthia

2012-06-07

365

Seasonal growth and lipid storage of the circumglobal, subantarctic copepod, Neocalanus tonsus (Brady)  

NASA Astrophysics Data System (ADS)

Neocalanus tonsus (Brady) was sampled between October 1984 and September 1985 in the upper 1000 m of the water column off southeastern New Zealand. The apparent spring growth increment of copepodid stage V (CV) differed depending upon the constituent considered: dry mass increased 208 ?g, carbon 162 ?g, wax esters 143 ?g, but nitrogen only 5 ?g. Sterols and phospholipids remained relatively constant over this interval. Wax esters were consistently the dominant lipid class present in CV's, increasing seasonally from 57 to 90% of total lipids. From spring to winter, total lipid content of CV's increased from 22 to 49% of dry mass. Nitrogen declined from 10.9 to 5.4% of CV dry mass as storage compounds (wax esters) increased in importance relative to structural compounds. Egg lipids were 66% phospholipids. Upon first appearance of males and females in deep water in winter, lipid content and composition did not differ from co-occuring CV's, confirming the importance of lipids rather than particulate food as an energy source for deep winter reproduction of this species. Despite contrasting life histories, N. tonsus and subarctic Pacific Neocalanus plumchrus CV's share high lipid content, a predominance of wax esters over triacylglycerols as storage lipids, and similar wax ester fatty acid and fatty alcohol composition.

Ohman, Mark D.; Bradford, Janet M.; Jillett, John B.

1989-09-01

366

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

E-print Network

'i 96822 ABSTRACT Meninges, the connective tissue of the vertebrate cen- tral nervous system (CNS), have in the most external connective tissues (dura mater and epineurium) versus electron-lucent cells in the more internal connective tissues (pia-arachnoid and endoneurium-perineurium) was also found in the cope- pod CNS

Hartline, Daniel K.

367

Reproduction of the Arctic copepod Calanus hyperboreus in the Greenland Sea-field and laboratory observations  

Microsoft Academic Search

The seasonal vertical migration of adultCalanus hyperboreus Kryer and their female reproductive biology have been studied in the central Greenland Sea, based on 7-month coverage during\\u000a one annual cycle. Females dwelled in surface waters only between April and July. Gonad maturation began after the summer descent\\u000a into deeper waters between September and October in the absence of food. Breeding was

Hans-Jürgen Hirche; Barbara Niehoff

1996-01-01

368

Thin layers of bioluminescent copepods found at density discontinuities in the water column  

Microsoft Academic Search

To learn how organisms apportion space in the open ocean, biological oceanographers have sought to improve temporal and spatial\\u000a resolution of ocean sampling systems. Their objectives are to simultaneously measure physical, chemical and biological structure\\u000a in the water column in order to find significant correlations that may reveal underlying processes. Here we report one such\\u000a correlation between intense peaks of

E. A. Widder; S. Johnsen; S. A. Bernstein; J. F. Case; D. J. Neilson

1999-01-01

369

Long-term monitoring of fish farms: application of Nematode/Copepod index to oligotrophic conditions.  

PubMed

Interannual variability (2003-2008) of meiofaunal assemblages were analyzed in sediments beneath fish cages (Impact group) and in areas not affected by aquaculture activities (Control group). Organisms responded with spatial and seasonal variation in meiofauna assemblages, with an abrupt increase of abundances in locations beneath fish cages throughout the study period. This increase was greater during the last sampling year (2008) and mainly due to high abundances of nematodes. Univariate analyses showed differences between control and impacted sites at both sites, however, only significant variations were found in Los Gigantes, which are consistent with seasonal meiofauna variations throughout the study period. These results are partially explained by differences in current velocity between both sampling areas. The Ne/Co index showed the same trend and it seems to be a reliable index in sediment slightly affected by aquaculture wastes. This index is especially recommended in oligotrophic areas (e.g. Canary Islands) where meiofaunal assemblages are poorly represented in terms of abundances. PMID:22317790

Riera, Rodrigo; Sanchez-Jerez, Pablo; Rodríguez, Myriam; Monterroso, Oscar; Ramos, Eva

2012-04-01

370

Factors influencing the induction of diapausing egg production in the calanoid copepod Diaptomus leptopus  

Microsoft Academic Search

Field and laboratory studies were carried out between 1995 and 1997 on four populations of Diaptomus leptopus found in seasonally temporary, occasionally temporary, and a permanent environment to assess the relative importance of photoperiod and temperature regimes versus other proximate local cues in inducing diapause egg production. Patterns of diapausing and subitaneous egg production were determined by observation of individual

David W. Piercey; Edward J. Maly

2000-01-01

371

Bioactive Compounds Offered in Microcapsules to Determine the Nutritional Value of Copepods’ Natural Diet  

PubMed Central

Experiments were performed, feeding Calanus pacificus seston and a food consisting of seston and microcapsules (?-caps), i.e., protein and lipid ?-caps to test for potential biochemical limitation. Seston was collected off Scripps Pier (La Jolla, CA, USA). Whereas protein ?-caps were too small to be efficiently ingested, lipid ?-caps rich in ?3-highly-unsaturated fatty acids (?3-HUFA) were ingested similarly to natural seston and lipids were assimilated. However, egg production experiments exhibited that animals fed with lipid ?-caps didn’t produce significantly more eggs than with seston of equal carbon concentration and egg production even declined when the diet consisted of 50% lipid ?-caps. Thus, the content of certain ?3-HUFA seemed to have been sufficiently high in seston to prevent limitation. Algal counts revealed that seston consisted mainly of plankton rich in those fatty acids, such as cryptophytes, dinoflagellates, diatoms, and ciliates in the edible size range. This might be characteristic for upwelling systems like the area off Southern California which are known for high trophic transfer efficiency. PMID:23857112

Müller-Navarra, Dörthe C.; Huntley, Mark E.

2013-01-01

372

Variation in Body Shape across Species and Populations in a Radiation of Diaptomid Copepods  

PubMed Central

Inter and intra-population variation in morphological traits, such as body size and shape, provides important insights into the ecological importance of individual natural populations. The radiation of Diaptomid species (~400 species) has apparently produced little morphological differentiation other than those in secondary sexual characteristics, suggesting sexual, rather than ecological, selection has driven speciation. This evolutionary history suggests that species, and conspecific populations, would be ecologically redundant but recent work found contrasting ecosystem effects among both species and populations. This study provides the first quantification of shape variation among species, populations, and/or sexes (beyond taxonomic illustrations and body size measurements) to gain insight into the ecological differentiation of Diaptomids. Here we quantify the shape of five Diaptomid species (family Diaptomidae) from four populations each, using morphometric landmarks on the prosome, urosome, and antennae. We partition morphological variation among species, populations, and sexes, and test for phenotype-by-environment correlations to reveal possible functional consequences of shape variation. We found that intraspecific variation was 18-35% as large as interspecific variation across all measured traits. Interspecific variation in body size and relative antennae length, the two traits showing significant sexual dimorphism, were correlated with lake size and geographic location suggesting some niche differentiation between species. Observed relationships between intraspecific morphological variation and the environment suggest that divergent selection in contrasting lakes might contribute to shape differences among local populations, but confirming this requires further analyses. Our results show that although Diaptomid species differ in their reproductive traits, they also differ in other morphological traits that might indicate ecological differences among species and populations. PMID:23826384

Hausch, Stephen; Shurin, Jonathan B.; Matthews, Blake

2013-01-01

373

Effect of solar ultraviolet radiation on survival of krill larvae and copepods in Antarctic Ocean  

Microsoft Academic Search

The effect of solar ultraviolet radiation on the survival rate of Antarctic zooplankton was examined in February–March in\\u000a 2002. We investigated survival rate of calyptopis larvae of Euphausia superba and late copepodite stages (IV and V) of large dominant calanoid species, Calanoides acutus and Calanus propinquus reared in quartz jars with three different radiation regimes (total radiation, exclusion of UVB,

Syuhei Ban; Nobuaki Ohi; Sandric Chee Yew Leong; Kunio T. Takahashi; Christian W. Riser; Satoru Taguchi

2007-01-01

374

Copepod life cycle adaptations and success in response to phytoplankton spring bloom phenology  

Microsoft Academic Search

In a seasonal environment, the timing of reproduction is usually scheduled to maximize the survival of offspring. Within deep water bodies, the phytoplankton spring bloom provides a short time window of high food quantity and quality for herbivores. The onset of algal bloom development, however, varies strongly from year to year due to interannual variability in meteorological conditions. Furthermore, the

HANNO S EEBENS; U LRICH

2009-01-01

375

Copepod communities related to water masses in the southwest East China Sea  

Microsoft Academic Search

The East China Sea is characterized by a complex hydrographic regime and high biological productivity and diversity. This\\u000a environmental setting in particular challenged a case study on the use of mesozooplankton community parameters as indicators\\u000a of water masses. In order to reveal spatial patterns of zooplankton communities during summer, a large scale oceanic transect\\u000a study was conducted. Two transects were

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

2008-01-01

376

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

Microsoft Academic Search

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

L. Seuront

2010-01-01

377

Zooplankton community structure and dynamics in the Arctic Canada Basin during a period of intense environmental change (2004-2009)  

NASA Astrophysics Data System (ADS)

were sampled in the Canada Basin in the summers of 2004, 2006, 2007, 2008, and fall 2009. Six taxa (Calanus hyperboreus, Calanus glacialis, Oithona similis, Limacina helicina, Microcalanus pygmaeus, and Pseudocalanus spp.) accounted for 77-91% of the abundance in all years, and 70-80% of biomass in 2004-2008. The biomass of C. hyperboreus and C. glacialis was reduced in 2009, likely due to seasonal migration below the sampling depth. Mean abundance was consistent across surveys while biomass increased from 18.92 to 32.56 mg dry weight m-3 between 2004 and 2008. Multivariate analysis identified a clear separation between shelf and deep basin (>1000 m) assemblages. Within the deep basin abundance and biomass were higher in the west, associated with a higher chlorophyll maximum. In 2007 and 2008 considerable heterogeneity developed in the assemblage structure, associated with variability in the contribution of the short-lived (<1 year) copepod species O. similis and M. pygmaeus. Conversely, the long lived (?2 years) C. hyperboreus and C. glacialis showed an increasingly consistent spatial distribution of high biomass from 2004 to 2008. We propose that a greater dependence on autochthonous basin production by the short-lived species resulted in their decreased secondary production in the freshening Beaufort Gyre in 2007 and 2008. Conversely, long-lived species were supported by high allochthonous production on the Beaufort and Chukchi shelves and lipid stores accumulated from this source enabled them to persist in the low chlorophyll a biomass conditions of the Canada Basin.

Hunt, Brian P. V.; Nelson, R. John; Williams, Bill; McLaughlin, Fiona A.; Young, Kelly V.; Brown, Kristina A.; Vagle, Svein; Carmack, Eddy C.

2014-04-01

378

Ecological interactions affecting population-level responses to chemical stress in Mesocyclops leuckarti.  

PubMed

Higher tiers of ecological risk assessment (ERA) consider population and community-level endpoints. At the population level, the phenomenon of density dependence is one of the most important ecological processes that influence population dynamics. In this study, we investigated how different mechanisms of density dependence would influence population-level ERA of the cyclopoid copepod Mesocyclops leuckarti under toxicant exposure. We used a combined approach of laboratory experiments and individual-based modelling. An individual-based model was developed for M. leuckarti to simulate population dynamics under triphenyltin exposure based on individual-level ecological and toxicological data from laboratory experiments. The study primarily aimed to-(1) determine which life-cycle processes, based on feeding strategies, are most significant in determining density dependence (2) explore how these mechanisms of density dependence affect extrapolation from individual-level effects to the population level under toxicant exposure. Model simulations showed that cannibalism of nauplii that were already stressed by TPT exposure contributed to synergistic effects of biotic and abiotic factors and led to a twofold stress being exerted on the nauplii, thereby resulting in a higher population vulnerability compared to the scenario without cannibalism. Our results suggest that in population-level risk assessment, it is easy to underestimate toxicity unless underlying ecological interactions including mechanisms of population-level density regulation are considered. This study is an example of how a combined approach of experiments and mechanistic modelling can lead to a thorough understanding of ecological processes in ecotoxicology and enable a more realistic ERA. PMID:25048925

Kulkarni, Devdutt; Hommen, Udo; Schäffer, Andreas; Preuss, Thomas G

2014-10-01

379

Impact of zooplankton grazing on Alexandrium blooms in the offshore Gulf of Maine  

NASA Astrophysics Data System (ADS)

Zooplankton grazing was investigated by shipboard experiments during natural blooms of Alexandrium spp. in the offshore Gulf of Maine in spring and/or summer of 1998, 2000, and 2001. Grazing studies were done in conjunction with studies of accumulation of Alexandrium toxins in the zooplankton, as part of the ECOHAB-Gulf of Maine regional program. Several species of copepods, marine cladocerans, and appendicularians were allowed to graze upon natural phytoplankton assemblages, at ambient temperatures (14-17 °C). Grazing was measured by quantitative microscopic analyses of disappearance of phytoplankton cells in initial, control, and experimental food suspensions. Thus, we were able to examine grazing upon Alexandrium in comparison to grazing on other co-occurring phytoplankton taxa. Even during Alexandrium "blooms," this dinoflagellate was a minor component of the overall phytoplankton assemblage. It was present at stations where grazing experiments were conducted at levels of 0.12-7.57×10 3 cells l -1, or 0.03-3.93% of total phytoplankton cells. Maximum ingestion of Alexandrium accounted for only up to 3.2% of total cells ingested. Phytoplankton assemblages were dominated by athecate microflagellates, and to a lesser extent by diatoms and non-toxic dinoflagellates. Microflagellates were present at abundances of 159.62-793.93 cells ml -1, or 60.6-95.56% of total cells. Grazing on microflagellates accounted for 35.59-98.21% of total grazing. Grazing on Alexandrium spp. and microflagellates was generally non-selective, with these taxa being ingested in similar proportions to their availability in food assemblages. Grazing on diatoms was selective, with diatoms being disproportionately ingested, compared to their proportions in food assemblages. There were no apparent adverse effects of Alexandrium on grazers during incubations of 18-24 h, and grazer survival was 100%. Estimated daily zooplankton grazing impact on Alexandrium spp. field populations by field populations of experimental grazers averaged 5.79% (range=0-117%). Extrapolating experimentally determined grazing rates to total zooplankton assemblages increased potential grazing impact to 0-667.77% (mean=114.7%). However, these potential impacts are likely overestimations, because toxin accumulation data indicated that many of the most-abundant zooplankters ( Oithona similis copepodites and copepod nauplii) likely graze only minimally upon Alexandrium spp. Thus, antipredation effects of high concentrations of Alexandrium on some grazers reported from some laboratory studies may only occur rarely in nature, because of low individual zooplankter grazing rates on Alexandrium, and dilution of grazing upon it by grazing on other food sources such as abundant microflagellates and diatoms.

Turner, Jefferson T.; Borkman, David G.

2005-09-01

380

Mesoscale distribution and community composition of zooplankton in the Mozambique Channel  

NASA Astrophysics Data System (ADS)

Recent studies have shown the Mozambique Channel to exhibit high mesoscale variability, but how mesoscale features influence the zooplankton community in this region is not known. The biovolume, biomass, vertical distribution and community composition of mesozooplankton (>200 µm) associated with mesoscale eddies in the Mozambique Channel was investigated during four cruises in September 2007, December 2008, November 2009 and April/May 2010. Stations were categorized according to their location in cyclonic (cold-core) or anticyclonic (warm-core) eddies, frontal, divergence or shelf regions. Mean mesozooplankton biovolume in the upper 200 m was 0.33 ml m-3, with zooplankton largely concentrated in the upper 100 m during all four cruises (weighted mean depth=66.6 m). Sampling depth was the most important predictor of biovolume, which was greatest for net samples with a mid-depth of 0-40 m, but declined deeper in the water column. Biovolume at the shelf (0.37 ml m-3), divergence and cyclonic eddy stations (0.31 ml m-3) was significantly greater than at frontal and anticyclonic eddy stations (0.20 ml m-3). Mean biovolume was significantly higher during 2008 and 2010 compared to 2007 and 2009, and was also significantly higher for samples collected at night (and twilight) than during the day. The mesozooplankton community in 2007 was strongly dominated by small copepods (~70-80% abundance) followed by appendicularians (10%), ostracods (8%) and chaetognaths (7%). The most abundant copepods were the Paracalanids, Oncaea spp., Oithona spp. and Corycaeus spp. Multivariate analysis showed that the communities in 2007 and 2008 were most strongly structured by depth, but classification (cyclonic/anticyclonic) was also important in 2007 when mesoscale features were more strongly developed. Zooplankton assemblages showed a high degree of homogeneity, with differences between mesoscale features largely due to differing abundances of similar taxa. These observations suggest that mesoscale eddy and shelf interactions play a fundamental role in shaping the Mozambique Channel pelagic ecosystem through the concentration, enhanced growth and redistribution of zooplankton communities. Although frontal areas between eddies were poor in zooplankton biomass, the extensive inter-eddy divergence areas were as rich in biomass as the small cyclonic eddy core regions. These patterns are important for understanding the favorability of observed foraging areas for higher trophic levels.

Huggett, Jenny A.

2014-02-01

381

Physical and biological characteristics of the pelagic system across Fram Strait to Kongsfjorden  

NASA Astrophysics Data System (ADS)

The Fram Strait is very important with regard to heat and mass exchange in the Arctic Ocean, and the large quantities of heat carried north by the West Spitsbergen Current (WSC) influence the climate in the Arctic region as a whole. A large volume of water and ice is transported through Fram Strait, with net water transport of 1.7-3.2 Sv southward in the East Greenland Current and a volume ice flux in the range of 0.06-0.11 Sv. The mean annual ice flux is about 866,000 km 2 yr -1. The Kongsfjorden-Krossfjorden fjord system on the coast of Spitsbergen, or at the eastern extreme of Fram Strait, is mainly affected by the northbound transport of water in the WSC. Mixing processes on the shelf result in Transformed Atlantic Water in the fjords, and the advection of Atlantic water also carries boreal fauna into the fjords. The phytoplankton production is about 80 g C m -2 yr -1 in Fram Strait, and has been estimated both below and above this for Kongsfjorden. The zooplankton fauna is diverse, but dominated in terms of biomass by calanoid copepods, particularly Calanus glacialis and C. finmarchicus. Other important copepods include C. hyperboreus, Metridia longa and the smaller, more numerous Pseudocalanus ( P. minutus and P. acuspes), Microcalanus ( M. pusillus and M. pygmaeus) and Oithona similis. The most important species of other taxa appear to be the amphipods Themisto libellula and T. abyssorum, the euphausiids Thysanoessa inermis and T. longicaudata and the chaetognaths Sagitta elegans and Eukrohnia hamata. A comparison between the open ocean of Fram Strait and the restricted fjord system of Kongsfjorden-Krossfjorden can be made within limitations. The same species tend to dominate, but the Fram Strait zooplankton fauna differs by the presence of meso- and bathypelagic copepods. The seasonal and inter-annual variation in zooplankton is described for Kongsfjorden based on the record during July 1996-2002. The ice macrofauna is much less diverse, consisting of a handful of amphipod species and the polar cod. The ice-associated biomass transport of ice-amphipods was calculated, based on the ice area transport, at about 3.55 × 10 6 ton wet weight per year or about 4.2 × 10 5 t C yr -1. This represents a large energy input to the Greenland Sea, but also a drain on the core population residing in the multi-year pack ice (MYI) in the Arctic Ocean. A continuous habitat loss of MYI due to climate warming will likely reduce dramatically the sympagic food source. The pelagic and sympagic food web structures were revealed by stable isotopes. The carbon sources of particulate organic matter (POM), being Ice-POM and Pelagic-POM, revealed different isotopic signals in the organisms of the food web, and also provided information about the sympagic-pelagic and pelagic-benthic couplings. The marine food web and energy pathways were further determined by fatty acid trophic markers, which to a large extent supported the stable isotope picture of the marine food web, although some discrepancies were noted, particularly with regard to predator-prey relationships of ctenophores and pteropods.

Hop, Haakon; Falk-Petersen, Stig; Svendsen, Harald; Kwasniewski, Slawek; Pavlov, Vladimir; Pavlova, Olga; Søreide, Janne E.

2006-10-01

382

The study on highly expressed proteins as a function of an elevated ultraviolet radiation in the copepod, Tigriopus japonicus  

NASA Astrophysics Data System (ADS)

The objective of the study was to analyze constantlyhighly expressed proteins as a function of elevated midultraviolet (UVB, 280-315 nm) radiation in Tigriopus japonicus sensu lato ( T. japonicus s.l). We also analyzed associations between kinetics of radiation avoidance, measured as a covered distance per time unit, and highly expressed proteins. The obtained results indicate an increase in T. japonicus s.l. mobility between the control (no radiation) and mild UV radiation levels (15 kJ·m-2). Two-dimensional gel electrophoresis combined with MALDI-MS-MS resulted in 2D protein map comprising of 686 protein spots, of which 19 were identified as highly expressed proteins across all experimental conditions. Obtained results indicate that calpain, vitellogenin, and collagenase are housekeeping protein that are expressed at a constant level independently of environmental changes and that adoption of a locomotive system for the avoidance of a UV source may be, at least partially, supported by hepatopancreas-driven metabolism.

Zubrzycki, Igor Z.; Lee, Seunghan; Lee, Kanghyun; Wiacek, Magdalena; Lee, Wonchoel

2012-06-01

383

Inhibitory effects of biocides on transcription and protein activity of acetylcholinesterase in the intertidal copepod Tigriopus japonicus.  

PubMed

Acetlycholinesterase (AChE) is a serine esterase that plays an important role in the hydrolytic degradation of acetylcholine. We investigated the modulatory potential of T. japonicus-AChE (TJ-AChE) for biocide response by cloning, sequencing, and characterizing the full-length genomic DNA of the TJ-AChE1 and TJ-AChE2 genes. The deduced TJ-AChE proteins were highly conserved across species and were distinctively separated into two subtypes, AChE1 and AChE2. Each TJ-AChE protein was closely phylogenetically clustered with invertebrate AChE1 and AChE2 proteins. Transcriptional level of TJ-AChE1 was higher than TJ-AChE2 in all developmental stages. TJ-AChE1 mRNA decreased in response to five biocides (alachlor, chlorpyrifos, dimethoate, endosulfan, lindane,) but not in the molinate-exposed group. TJ-AChE2 decreased significantly only in response to chlorpyrifos and lindane. TJ-AChE enzymatic activity was significantly inhibited when exposed to alachlor, chlorpyrifos, endosulfan, or lindane for 24 h. This study elucidates potential endogenous mechanisms of biocide-induced neurotoxicity in T. japonicas. PMID:25468639

Lee, Jin Wuk; Kim, Bo-Mi; Jeong, Chang-Bum; Won, Eun-Ji; Rhee, Jae-Sung; Lee, Jae-Seong

2015-01-01

384

SYMPATRY OF DISTINCT MITOCHONDRIAL DNA LINEAGES IN A COPEPOD INHABITING ESTUARINE CREEKS IN THE SOUTHEASTERN USA. (R827397)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

385

THE EFFECT OF NUTRITION ON THE RESPONSE OF FIELD POPULATIONS OF THE CALANOID COPEPOD 'ACARTIA TONSA' TO COPPER  

EPA Science Inventory

Continuous flow toxicity tests were conducted on field populations of adult Acartia tonsa collected from Narragansett Bay. Potential algal food at the collection site was estimated from ATP and chlorophyll analysis. There was positive correlation (P < 0.01) between chlorophyll a ...

386

MAINTENANCE OF DISTINCT MITOCHONDRIAL DNA LINEAGES IN SYMPATRY IN COPEPOD INHABITING ESTUARINE CREEKS IN THE SOUTHEASTERN USA. (R825439)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

387

High cryptic diversity across the global range of the migratory planktonic copepods Pleuromamma piseki and P. gracilis.  

PubMed

Although holoplankton are ocean drifters and exhibit high dispersal potential, a number of studies on single species are finding highly divergent genetic clades. These cryptic species complexes are important to discover and describe, as identification of common marine species is fundamental to understanding ecosystem dynamics. Here we investigate the global diversity within Pleuromamma piseki and P. gracilis, two dominant members of the migratory zooplankton assemblage in subtropical and tropical waters worldwide. Using DNA sequence data from the mitochondrial gene cytochrome c oxidase subunit II (mtCOII) from 522 specimens collected across the Pacific, Atlantic and Indian Oceans, we discover twelve well-resolved genetically distinct clades in this species complex (Bayesian posterior probabilities >0.7; 6.3-17% genetic divergence between clades). The morphologically described species P. piseki and P. gracilis did not form monophyletic groups, rather they were distributed throughout the phylogeny and sometimes co-occurred within well-resolved clades: this result suggests that morphological characters currently used for taxonomic identification of P. gracilis and P. piseki may be inaccurate as indicators of species' boundaries. Cryptic clades within the species complex ranged from being common to rare, and from cosmopolitan to highly restricted in distribution across the global ocean. These novel lineages appear to be ecologically divergent, with distinct biogeographic distributions across varied pelagic habitats. We hypothesize that these mtDNA lineages are distinct species and suggest that resolving their systematic status is important, given the ecological significance of the genus Pleuromamma in subtropical-tropical waters worldwide. PMID:24167556

Halbert, Kristin M K; Goetze, Erica; Carlon, David B

2013-01-01

388

Comprehensive Transcriptome Study to Develop Molecular Resources of the Copepod Calanus sinicus for Their Potential Ecological Applications  

PubMed Central

Calanus sinicus Brodsky (Copepoda, Crustacea) is a dominant zooplanktonic species widely distributed in the margin seas of the Northwest Pacific Ocean. In this study, we utilized an RNA-Seq-based approach to develop molecular resources for C. sinicus. Adult samples were sequenced using the Illumina HiSeq 2000 platform. The sequencing data generated 69,751 contigs from 58.9 million filtered reads. The assembled contigs had an average length of 928.8?bp. Gene annotation allowed the identification of 43,417 unigene hits against the NCBI database. Gene ontology (GO) and KEGG pathway mapping analysis revealed various functional genes related to diverse biological functions and processes. Transcripts potentially involved in stress response and lipid metabolism were identified among these genes. Furthermore, 4,871 microsatellites and 110,137 single nucleotide polymorphisms (SNPs) were identified in the C. sinicus transcriptome sequences. SNP validation by the melting temperature (Tm)-shift method suggested that 16 primer pairs amplified target products and showed biallelic polymorphism among 30 individuals. The present work demonstrates the power of Illumina-based RNA-Seq for the rapid development of molecular resources in nonmodel species. The validated SNP set from our study is currently being utilized in an ongoing ecological analysis to support a future study of C. sinicus population genetics. PMID:24982883

Yang, Qing; Sun, Fanyue; Yang, Zhi; Li, Hongjun

2014-01-01

389

First record of harpacticoid copepods from Lake Tahoe, United States: two new species of Attheyella (Harpacticoida, Canthocamptidae)  

PubMed Central

Abstract Benthic harpacticoids were collected for the first time at Lake Tahoe, California-Nevada, United States. Two species were identified as members of the genus Attheyella Brady, 1880. The genus Attheyella comprises about 150 species within six subgenera, but only twelve species have previously been reported from North American freshwater habitats. The two new species of Attheyella described here have a 3-segmented endopod on P1 and 2-segmented P2–P4 endopods, the distal segment of exopod of P2–P4 has three outer spines, and the P5 has five setae on the exopod and six setae on the baseoendopod. Attheyella (Attheyella) tahoensis sp. n. most closely resembles Attheyella (Attheyella) idahoensis (Marsh, 1903) from Idaho, Montana, and Alaska (United States) and Attheyella (Attheyella) namkungi Kim, Soh & Lee, 2005 from Gosu Cave in South Korea. They differ mainly by the number of setae on the distal endopodal segment of P2–P4. In addition, intraspecific variation has been observed on the caudal rami. Attheyella (Neomrazekiella) tessiae sp. n. is characterized by the extension of P5 baseoendopod, 2-segmented endopod of female P2–P3, and naked third seta of male P5 exopod. The two new species are likely endemic to Lake Tahoe, an isolated alpine lake within the Great Basin watershed in the western United States.

Bang, Hyun Woo; Baguley, Jeffrey G.; Moon, Heejin

2015-01-01

390

An Example of How Barcodes Can Clarify Cryptic Species: The Case of the Calanoid Copepod Mastigodiaptomus albuquerquensis (Herrick)  

PubMed Central

Background The freshwater calanoid Mastigodiaptomus is a genus with high richness in the Americas and is composed of nine species, seven recorded in Mexico and four that are apparently endemic to small areas. Mastigodiaptomus albuquerquensis is a common, widely distributed species ranging from the southern USA to Central America. This species can be easily identified by a notable butterfly-like sclerotization on the basis of the right fifth leg of males. Nevertheless, morphological differences observed among populations throughout this species distributional range have led to the description of several related species or subspecies, such as M. albuquerquensis patzcuarensis from Lake Pátzcuaro in the Central Plateau of Mexico. Methods Genetic results based on barcodes, morphology based on scanning electron and light microscopy images, and morphometric analyses were used to describe cryptic species within the M. albuquerquensis complex. Results The morphological analyses coincided partially with the genetic markers, suggesting the existence of at least two sibling species: M. albuquerquensis s. str. and M. patzcuarensis. A third species was genetically separated but was morphologically indistinguishable from the M. patzcuarensis group. Conclusions Hidden diversity has been a major problem in establishing real patterns of species distribution and genetic acquisition from megadiverse hotspots such as Mexico, where the Nearctic and the Neotropical regions of the Americas meet. Barcodes can help taxonomists to reveal and formally name these new species. Here, we describe two of three potential species highlighted by the use of barcodes: M. albuquerquensis s. str. in the northern semi-desert and M. patzcuarensis on the Central Plateau at more than 2000 m above sea level. PMID:24465470

Gutiérrez-Aguirre, Martha Angélica; Cervantes-Martínez, Adrián; Elías-Gutiérrez, Manuel

2014-01-01

391

Effects of pressure, temperature and oxygen on the oxygen consumption rate of the Midwater copepod Gaussia princeps  

Microsoft Academic Search

Gaussia princeps is shown to be a diurnal vertical migrator which spends its days below 400 m in the oxygen minimum layer and migrates to shallower depths (200 to 300 m) at night. This species consumption was measured at 3.5°, 7° and 10°C and 1, 14, 28, 61, 121 and 181 atm of hydrostatic pressure (1 atm corresponds to approximately

J. J. Childress

1976-01-01

392

Production, oxygen respiration rates, and sinking velocity of copepod fecal pellets: Direct measurements of ballasting by opal and calcite  

E-print Network

measurements of ballasting by opal and calcite Helle Ploug1 Alfred Wegener Institute for Polar and Marine independent on diet (range: 0.08­ 0.21 d21). Because of ballasting of opal and calcite, sinking velocities

Matthews, Adrian

393

Comprehensive transcriptome study to develop molecular resources of the copepod Calanus sinicus for their potential ecological applications.  

PubMed

Calanus sinicus Brodsky (Copepoda, Crustacea) is a dominant zooplanktonic species widely distributed in the margin seas of the Northwest Pacific Ocean. In this study, we utilized an RNA-Seq-based approach to develop molecular resources for C. sinicus. Adult samples were sequenced using the Illumina HiSeq 2000 platform. The sequencing data generated 69,751 contigs from 58.9 million filtered reads. The assembled contigs had an average length of 928.8?bp. Gene annotation allowed the identification of 43,417 unigene hits against the NCBI database. Gene ontology (GO) and KEGG pathway mapping analysis revealed various functional genes related to diverse biological functions and processes. Transcripts potentially involved in stress response and lipid metabolism were identified among these genes. Furthermore, 4,871 microsatellites and 110,137 single nucleotide polymorphisms (SNPs) were identified in the C. sinicus transcriptome sequences. SNP validation by the melting temperature (T m )-shift method suggested that 16 primer pairs amplified target products and showed biallelic polymorphism among 30 individuals. The present work demonstrates the power of Illumina-based RNA-Seq for the rapid development of molecular resources in nonmodel species. The validated SNP set from our study is currently being utilized in an ongoing ecological analysis to support a future study of C. sinicus population genetics. PMID:24982883

Yang, Qing; Sun, Fanyue; Yang, Zhi; Li, Hongjun

2014-01-01

394

Climate-mediated changes in zooplankton community structure for the eastern Bering Sea  

NASA Astrophysics Data System (ADS)

Zooplankton are critical to energy transfer between higher and lower trophic levels in the eastern Bering Sea ecosystem. Previous studies from the southeastern Bering Sea shelf documented substantial differences in zooplankton taxa in the Middle and Inner Shelf Domains between warm and cold years. Our investigation expands this analysis into the northern Bering Sea and the south Outer Domain, looking at zooplankton community structure during a period of climate-mediated, large-scale change. Elevated air temperatures in the early 2000s resulted in regional warming and low sea-ice extent in the southern shelf whereas the late 2000s were characterized by cold winters, extensive spring sea ice, and a well-developed pool of cold water over the entire Middle Domain. The abundance of large zooplankton taxa such as Calanus spp. (C. marshallae and C. glacialis), and Parasagitta elegans, increased from warm to cold periods, while the abundance of gelatinous zooplankton (Cnidaria) and small taxa decreased. Biomass followed the same trends as abundance, except that the biomass of small taxa in the southeastern Bering Sea remained constant due to changes in abundance of small copepod taxa (increases in Acartia spp. and Pseudocalanus spp. and decreases in Oithona spp.). Statistically significant changes in zooplankton community structure and individual species were greatest in the Middle Domain, but were evident in all shelf domains, and in both the northern and southern portions of the eastern shelf. Changes in community structure did not occur abruptly during the transition from warm to cold, but seemed to begin gradually and build as the influence of the sea ice and cold water temperatures persisted. The change occurred one year earlier in the northern than the southern Middle Shelf. These and previous observations demonstrate that lower trophic levels within the eastern Bering Sea respond to climate-mediated changes on a variety of time scales, including those shorter than the commonly accepted quasi-decadal time periods. This lack of resilience or inertia at the lowest trophic levels affects production at higher trophic levels and must be considered in management strategy evaluations of living marine resources.

Eisner, Lisa B.; Napp, Jeffrey M.; Mier, Kathryn L.; Pinchuk, Alexei I.; Andrews, Alexander G.

2014-11-01

395

The ice fauna in the shallow southwestern Beaufort Sea, Arctic Ocean  

NASA Astrophysics Data System (ADS)

Sympagic fauna were studied in seasonal fast ice adjacent to Narwhal Island during the spring of 1979 and 1980, with emphasis on the origin of the fauna and its relationship to contiguous pelagic and benthic communities. The results of five subprojects are reviewed and compared with recent literature. Within Stefansson Sound, inshore of Narwhal Island, total sympagic meiofaunal densities and species diversity were low. In March 1979, the dominant taxa were polychaete larvae and crustacean nauplii, while in May the dominant group was Nematoda. Total numerical densities were low, ranging from 4500 to 8000 per m 2. During the spring of 1980 large numbers of invertebrate fauna concentrated at the undersurface of seasonal sea ice on the inner western Beaufort Sea continental shelf, seaward of Narwhal Island. The sympagic meiofauna were comprised primarily of benthic harpacticoid and cyclopoid copepods, turbellarians, nematode worms, and polychaete worm larvae. Total meiofaunal densities increased from about 6000 per m 2 in April to about 482,000 per m 2 in June. All life stages of Cyclopina gracilis (Copepoda: Cyclopoida) were present in the ice. This species appeared to reproduce continuously from early April to early June during the study period. The Harpacticus sp. (Copepoda: Harpaticoida) population consisted of one cohort whose individuals grew in size from April to early June. The sympagic macrofauna consisted entirely of amphipod crustaceans, primarily comprised of benthic species. Population size structure of the amphipod Pseudalibrotus (= Onisimus) litoralis was bimodal and there was a lack of intermediate growth stages. These characteristics indicate that this species has a two-year life cycle in the Beaufort Sea. The highest growth rate for P. litoralis coincided with maximal ice algal production. P. litoralis fed largely on meiofaunal Crustacea and amphipod fragments in April, but its diet switched to ice algae during the height of the bloom in late May-early June. Results indicate that P. litoralis, normally a shallow benthic species, uses the ice undersurface as a spawning site and a temporary nursery ground for its young during the spring. Beneath the ice, the input of total organic carbon to the bottom remained at fairly constant low levels from April through early June, 1980. Little carbon, exported from the ice community beneath the sea ice, reached the shallow sea floor. However, this food source is available to the benthos earlier than that from phytoplanktonic or benthic microalgal production that occurs later in the season after ice breakup.

Carey, Andrew G.

1992-06-01

396

DIFFERENTIAL SURVIVAL OF THREE MITOCHONDRIAL LINEAGES OF A MARINE BENTHIC COPEPOD EXPOSED TO A PESTICIDE MIXTURE. (R825279,R825439,R827397)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

397

DEVELOPMENT-STAGE SPECIFIC LIFE-CYCLE BIOASSAY FOR ASSESSMENT OF SEDIMENT-ASSOCIATED TOXICANT EFFECTS ON BENTHIC COPEPOD PRODUCTION. (R825279)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

398

DEVELOPMENTAL STAGE-SPECIFIC LIFE-CYCLE BIOASSAY FOR ASSESSMENT OF SEDIMENT-ASSOCIATED TOXICANT EFFECTS ON BENTHIC COPEPOD PRODUCTION. (R827397)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

399

TOLERANCE AND GENETIC RELATEDNESS OF THREE MEIOBENTHIC COPEPOD POPULATIONS EXPOSED TO SEDIMENT-ASSOCIATED CONTAMINANT MIXTURES: ROLE OF ENVIRONMENTAL HISTORY. (R825439)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

400

ECDYSTEROID CONCENTRATIONS THROUGH VARIOUS LIFE-STAGES OF THE MEIOBENTHIC HARPACTICOID COPEPOD, AMPHIASCUS TENUIREMIS AND THE BENTHIC ESTUARINE AMPHIPOD, LEPTOCHEIRUS PLUMULOSUS. (R827397)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

401

MOLECULAR POPULATION STRUCTURE OF THE BENTHIC COPEPOD MICROARTHRIDION LITTORALE ALONG THE SOUTHEASTERN AND GULF COASTS OF THE UNITED STATES. (R825439)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

402

SARGENT, J. R., AND S. FALK-PETERSEN. 1988. The lipid biochem-istry of Calanoid copepods. Hydrobiol. 167/168: 101-114.  

E-print Network

depletion of dissolved trace elements in oceans and lakes also coincides with increased phytoplankton. Biol. Ecol. 110: 53-68. STDTTRUP, J. G., AND J. J. JENSEN. 1990. The influence of algal diet on feeding- and Ni-rich sediments. Trace metal concentrations in many of the world's estu- aries are enriched

van Geen, Alexander

403

Without Gills: Localization of Osmoregulatory Function in the Copepod Eurytemora affinis Author(s): Kelsey Elizabeth Johnson, Lucile Perreau, Guy Charmantier, Mireille Charmantier-  

E-print Network

(s): Kelsey Elizabeth Johnson, Lucile Perreau, Guy Charmantier, Mireille Charmantier- Daures and Carol Eunmi reserved. 1522-2152/2014/8702-3058$15.00. DOI: 10.1086/674319 Kelsey Elizabeth Johnson1 Lucile Perreau2 Guy

Lee, Carol Eunmi