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1

Cyclopoid and harpacticoid copepods of the Laurentian Great Lakes  

USGS Publications Warehouse

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

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

1998-01-01

2

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

THE SARCOPLASMIC RETICULUM OF STRIATED MUSCLE OF A CYCLOPOID COPEPOD  

PubMed Central

The fine structure of the abdominal musculature of the copepod Macrocyclops albidus was investigated by electron microscopy. Tubules penetrate into the muscle fibers from the sarcolemma, continuity between the wall of the tubules and the sarcolemma being clear. A dense network of tubules envelops the myofibrils, its interstices being occupied by cisternal elements. At the Z lines the tubules traverse the interior of myofibrils, giving off branches which course longitudinally within the substance of the myofibrils. These branches are also accompanied by elongate, non-intercommunicating cisternae. Comparison of this fast acting copepod muscle with other vertebrate and invertebrate muscles indicates that the complexity of the tubular system is a function of the myofibrillar geometry, whereas the degree of development of the cisternal system is related to the contraction speed of the muscle. PMID:19866629

Fahrenbach, Wolf H.

1963-01-01

4

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

5

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

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

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

8

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

PubMed

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

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

2010-11-01

9

Observing free-swimming copepods mating  

PubMed Central

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

Strickler, J. R.

1998-01-01

10

Species composition of Black Sea marine planktonic copepods  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

11

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

PubMed

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

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

2013-12-17

12

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

13

Composite forces shape population dynamics of copepod crustaceans.  

PubMed

Understanding the processes that control species abundance and distribution is a major challenge in ecology, yet for a large number of potentially important organisms, we know little about the biotic and abiotic factors that influence population size. One group of aquatic organisms that defies traditional demographic analyses is the Crustacea, particularly those with complex life cycles. We used likelihood techniques and information theoretics to evaluate a suite of models representing alternative hypotheses on factors controlling the abundance of two copepod crustaceans in a small, tropical floodplain lake. Quantitative zooplankton samples were collected at three stations in a Venezuelan floodplain lake from June through December 1984; the average sampling interval was two days. We constructed a series of models with stage structure that incorporated six biotic and abiotic covariates in various combinations to account for temporal changes in abundance of these target species and in their population growth rates. Our analysis produced several novel insights into copepod population dynamics. We found that multiple forces affected the abundance of particular stages, that these factors differed between species as well as among stages within each species, and that biotic processes had the largest effects on copepod population dynamics. Density dependence had a large effect on the survival of Oithona amazonica copepodites and on population growth rate of Diaptomus negrensis. PMID:17503594

Twombly, S; Wang, Guiming; Hobbs, N Thompson

2007-03-01

14

Ecology and role of benthic copepods in northern lakes  

NASA Astrophysics Data System (ADS)

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

Sarvala, J.

1998-06-01

15

Prey Detection and Prey Capture in Copepod Nauplii  

PubMed Central

Copepod nauplii are either ambush feeders that feed on motile prey or they produce a feeding current that entrains prey cells. It is unclear how ambush and feeding-current feeding nauplii perceive and capture prey. Attack jumps in ambush feeding nauplii should not be feasible at low Reynolds numbers due to the thick viscous boundary layer surrounding the attacking nauplius. We use high-speed video to describe the detection and capture of phytoplankton prey by the nauplii of two ambush feeding species (Acartia tonsa and Oithona davisae) and by the nauplii of one feeding-current feeding species (Temora longicornis). We demonstrate that the ambush feeders both detect motile prey remotely. Prey detection elicits an attack jump, but the jump is not directly towards the prey, such as has been described for adult copepods. Rather, the nauplius jumps past the prey and sets up an intermittent feeding current that pulls in the prey from behind towards the mouth. The feeding-current feeding nauplius detects prey arriving in the feeding current but only when the prey is intercepted by the setae on the feeding appendages. This elicits an altered motion pattern of the feeding appendages that draws in the prey. PMID:23144712

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

2012-01-01

16

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.

17

Diel vertical migration of copepods in a Brazilian lake: a mechanism for decreasing risk of Chaoborus predation?  

PubMed

A comparison between two studies on diel vertical migration of two cyclopoid copepod species, in Lake Monte Alegre, undertaken in 1985/86 and 1999, revealed a change in their migratory behavior. In summer, during a period of marked stratification with low dissolved oxygen near the bottom, the organisms avoided the deepest layers, and migration was nocturnal or undetectable, in both periods. On other occasions, with partial or total circulation in the lake, a weak twilight migration of copepodites and adults in 1985 was replaced by the reverse in 1999. Differences were found among stages, with the weakest or undetectable migration being observed for nauplii. The migratory pattern change for copepodites and adults might be related with a recent predation pressure increase by Chaoborus larvae on copepods, after the virtual disappearance of their main cladoceran prey. PMID:15462303

Perticarrari, A; Arcifa, M S; Rodrigues, R A

2004-05-01

18

Abundance and spatial distribution of copepods on Georges Bank during the winter/spring period  

NASA Astrophysics Data System (ADS)

Abundant copepods on Georges Bank during the winter-spring period (January-June) 1995-1999 were Calanus finmarchicus, Metridia spp. (primarily M. lucens), Pseudocalanus spp., Oithona spp (primarily O. similis), Temora longicornis, Centropages typicus, and C. hamatus. The first four taxa had off-bank sources (Group I) while the last three (Group II) had on-bank sources. All Group I taxa were relatively low in abundance in January and then increased in abundance throughout the sampling period. C. finmarchicus and Metridia spp. showed similar changes in age structure with large numbers of nauplii initially, a maturation of the population in April, followed by a decline in nauplii in May and a resurgence in their numbers in June. These species never achieved high abundance on the shallow crest region of the Bank and became very low in abundance there during May and June. By contrast Pseudocalanus spp. and Oithona spp. increased in abundance throughout the sampling period and, although they were lower in abundance on the crest during winter (January-March) and early spring (April), were able to establish populations there and became abundant during May and June. Group II taxa were low in abundance during winter ( C. typicus was abundant initially but declined through April) and did not begin to increase until spring (April-June). Their populations were centered over the crest of the bank indicating a local source, either from resting eggs, or because of high egg production rates due to the higher chlorophyll levels there.

Durbin, Edward G.; Casas, Maria C.

2006-11-01

19

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

20

Copepod Response Behavior in Turbulence  

NASA Astrophysics Data System (ADS)

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

Krizan, Daniel

21

Sensitivity and response time of three common Antarctic marine copepods to metal exposure.  

PubMed

Understanding the sensitivity of Antarctic marine organisms to metals is essential in order to manage environmental contamination risks. To date toxicity studies conducted on Antarctic marine species are limited. This study is the first to examine the acute effects of copper and cadmium on three common coastal Antarctic copepods: the calanoids Paralabidocera antarctica and Stephos longipes, and the cyclopoid Oncaea curvata. These copepods responded slowly to metal exposure (4-7d) emphasising that the exposure period of 48-96 h commonly used in toxicity tests with temperate and tropical species is not appropriate for polar organisms. We found that a longer 7 d exposure period was the minimum duration appropriate for Antarctic copepods. Although sensitivity to metal exposure varied between species, copper was more toxic than cadmium in all three species. P.antarctica was the most sensitive with 7d LC50 values for copper and cadmium of 20 ?g L(-1) and 237 ?g L(-1) respectively. Sensitivities to copper were similar for both O. curvata (LC50=64 ?g L(-1)) and S. longipes (LC50=56 ?g L(-1)), while O. curvata was more sensitive to cadmium (LC50=901 ?g L(-1)) than S. longipes (LC50=1250 ?g L(-1)). In comparison to copepods from lower latitudes, Antarctic copepods were more sensitive to copper and of similar sensitivity or less sensitive to cadmium. This study highlights the need for longer exposure periods in toxicity tests with slow responding Antarctic biota in order to generate relevant sensitivity data for inclusion in site-specific environmental quality guidelines for Antarctica. PMID:25128632

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

2015-02-01

22

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

23

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

24

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

PubMed

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

Pombo, Maíra; Turra, Alexander; Paschoal, Fabiano; Luque, José Luis

2015-01-01

25

Advanced recruitment and accelerated population development in Arctic calanoid copepods of the North Water  

NASA Astrophysics Data System (ADS)

The timing of copepodite recruitment and population development of copepods in spring and early summer (April-July) were compared between the North Water polynya and Barrow Strait, a non-polynya region in the Canadian Archipelago. In the North Water, young copepodites (CI-CIII) of calanoid herbivores were concentrated in the cold and chlorophyll-rich water at the base of the Arctic surface layer, while later stages (CIV-CV) invaded the warmer surface layer. The phytoplankton bloom and the recruitment of the first cohort of copepodites of Calanus hyperboreus, C. glacialis, and Pseudocalanus spp started in May-June, some 1.5-3 months earlier than in Barrow Strait. Consistent with a precocious summer recruitment, population stage structure of these species in early spring (April-May) was more advanced in the North Water than in Barrow Strait. The recruitment in June of CI of the omnivore Metridia longa was advanced by at least 5 weeks in the polynya relative to Barrow Strait. We found no evidence for an acceleration of the population development of the small Microcalanus pygmaeus, Oithona similis or Oncaea borealis in the polynya. Once the recruitment of young copepodites had started, recruitment success (i.e. % of young copepodites in the population) increased primarily with Chl a concentration for C. hyperboreus, with both sea-surface temperature and Chl a for C. glacialis, and with temperature only for Pseudocalanus spp. Hence, depending on the species, both greater food availability and higher temperature resulting from reduced ice cover contributed to improve reproductive success in herbivorous copepods in the North Water relative to Barrow Strait. A climate-induced reduction of ice cover duration is predicted to favour the population growth of the predominant large calanoid copepods and Pseudocalanus on Arctic shelves.

Ringuette, Marc; Fortier, Louis; Fortier, Martin; Runge, Jeffrey A.; Bélanger, Simon; Larouche, Pierre; Weslawski, Jan-Marcin; Kwasniewski, Slawek

26

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

27

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

NASA Astrophysics Data System (ADS)

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

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

1998-08-01

28

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

29

PREDICTING DEVELOPMENT RATE OF COPEPOD EGGS  

Microsoft Academic Search

This paper is part of a continuing study of intrinsic controls of growth. develop ment and, implicitly, productivity of marine zooplankton. Copepods are particularly suitable for comparative studies of embryonic development rate because most spe cies hatch at a morphologically equivalent first naupliar stage. The effect of tem perature on size varies markedly among different geographical populations of the copepod

30

Production and Collection of Copepod Nauplii from Brackish Water Ponds  

Microsoft Academic Search

Copepod nauplii are a nutritious food item for first-feeding marine fish larvae. Unfortunately, mass culture techniques for producing copepod nauplii are not well established. Copepod nauplii can be collected from wild zooplankton populations or specially prepared ponds and transferred to larval fish tanks for feeding. This study evaluated the use of two trapping methods for harvesting zooplankton, particularly copepod nauplii,

Laban C. Lindley; Ronald P. Phelps

2009-01-01

31

PREPARATION OF COPEPODS FOR HISTOPATHOLOGICAL EXAMINATIONS  

EPA Science Inventory

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

32

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

33

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

34

Freshwater Copepods and Rotifers: Predators and their Prey  

Microsoft Academic Search

Three main groups of planktonic animals inhabit the limnetic zone of inland waters and compete for common food resources: rotifers, cladocerans and copepods. In addition to competition, their mutual relationships are strongly influenced by the variable, herbivorous and carnivorous feeding modes of the copepods. Most copepod species, at least in their later developmental stages, are efficient predators. They exhibit various

Zdenek Brandl

2005-01-01

35

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

36

Evidence for sex pheromones in planktonic copepods  

Microsoft Academic Search

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

STEVEN K. KATONA

1973-01-01

37

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

38

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

39

Have chondracanthid copepods co-speciated with their teleost hosts?  

Microsoft Academic Search

Chondracanthid copepods parasitise many teleost species and have a mobile larval stage. It has been suggested that copepod parasites, with free-living infective stages that infect hosts by attaching to their external surfaces, will have co-evolved with their hosts. We examined copepods from the genus Chondracanthusand their teleost hosts for evidence of a close co-evolutionary association by comparing host and parasite

Adrian M. Paterson; Robert Poulin

1999-01-01

40

Have chondracanthid copepods co-speciated with their teleost hosts?  

Microsoft Academic Search

Chondracanthid copepods parasitise many teleost species and have a mobile larval stage. It has been suggested that copepod parasites, with free-living infective stages that infect hosts by attaching to their external surfaces, will have co-evolved with their hosts. We examined copepods from the genus Chondracanthus and their teleost hosts for evidence of a close co-evolutionary association by comparing host and

Adrian M. Paterson; Robert Poulin

1999-01-01

41

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

42

Quantifying copepod kinematics in a laboratory turbulence apparatus  

NASA Astrophysics Data System (ADS)

We describe application of a new apparatus that permits simultaneous detailed observations of plankton behavior and turbulent velocities. We are able to acquire 3D trajectories amenable to statistical analyses for comparisons of copepod responses to well-quantified turbulence intensities that match those found in the coastal ocean environment. The turbulence characteristics consist of nearly isotropic and homogeneous velocity fluctuation statistics in the observation region. In the apparatus, three species of copepods, Acartia hudsonica, Temora longicornis, and Calanus finmarchicus were exposed separately to stagnant water plus four sequentially increasing levels of turbulence intensity. Copepod kinematics were quantified via several measures, including transport speed, motility number, net-to-gross displacement ratio, number of escape events, and number of animals phototactically aggregating per minute. The results suggest that these copepods could control their position and movements at low turbulence intensity. At higher turbulence intensity, the copepods movement was dominated by the water motion, although species-specific modifications due to size and swimming mode of the copepod influenced the results. Several trends support a dome-shaped variation of copepod kinematics with increasing turbulence. These species-specific trends and threshold quantities provide a data set for future comparative analyses of copepod responses to turbulence of varying duration as well as intensity.

Yen, J.; Rasberry, K. D.; Webster, D. R.

43

Photoprotection by carotenoid pigments in the copepod Diaptomus nevadensis.  

PubMed Central

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

Hairston, N C

1976-01-01

44

Copepods under turbulence: grazing, behavior and metabolic rates  

Microsoft Academic Search

SUMMARY: This review focuses on the effects of small-scale turbulence on the rate processes of copepods, an important group of planktonic animals, and on their consequences for the dynamics of pelagic ecosystems. Turbulent water motion enhances the encounter rates between planktonic organisms and their food, changing the perception of the food environment for copepods and other planktonic animals. As a

C. TURBULENCE; E. SAIZ MARRASÉ; J. M. REDONDO; MIGUEL ALCARAZ

45

Photoprotection by carotenoid pigments in the copepod Diaptomus nevadensis.  

PubMed

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

Hairston, N C

1976-03-01

46

Photoprotection by Carotenoid Pigments in the Copepod Diaptomus nevadensis  

Microsoft Academic Search

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

Nelson G. Hairston

1976-01-01

47

Photoprotection by carotenoid pigments in the copepod Diaptomus nevadensis  

Microsoft Academic Search

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

N. G. Hairston; N. G. Jr

1976-01-01

48

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

49

Novel Organization and Development of Copepod Myelin. I. Ontogeny  

E-print Network

report of copepod myelin based on light microscopy (Lowe, 1935) was confirmed in passing in several in general terms (Zalc and Colman, 2000). By going beyond a single instance of this innova- tion, analyzing

Hartline, Daniel K.

50

Nuclear genes from the copepod Calanus finmarchicus.  

PubMed

For biological oceanography it is important to understand the coupling between physical and biological processes in pelagic systems. The calanoid copepod Calanus finmarchicus dominates the zoo-plankton biomass and is an important link between primary producers and higher trophic levels in the northern Atlantic. Thus understanding how the physical environment affects gene expression or population genetics in this species is important. However, very few nuclear genes have been characterized from this species, making it difficult to perform these types of studies. Four cDNAs encoding actin, hexokinase, phosphoglucose isomerase, and phosphofructokinase, as well as a hexokinase genomic DNA, have been isolated and characterized. These sequences constitute important molecular tools for biological oceanographers. PMID:7670600

Crawford, D L

1995-09-01

51

The ontogeny and phylogeny of copepod antennules  

PubMed Central

Comparative analysis of the development of antennulary segmentation and setation patterns across six orders of copepods revealed numerous common features. These features are combined to produce a hypothetical general model for antennulary development in the Copepoda as a whole. In this model most compound segments result from the failure of expression of articulations separating ancestral segments. In adult males, however, compound segments either side of the neocopepodan geniculation are typically formed by secondary fusion at the last moult from CoV (stage 5). The array of segments distal to the articulation separating segments XX and XXI is highly conserved both in ontogeny and phylogeny: typically the distal segmentation of the adult female is already present in the CoI. A maximum of three setae is added to the distal array during the entire copepodid phase. This morphological conservatism is interpreted as evidence of the functional continuity of the distal setal array as a mechanosensory system providing early warning of approaching predators. Sexual dimorphism typically appears late in development; the male undergoing modifications especially at the final moult to sexual maturity. These modifications include the formation of the neocopepodan geniculation at the XX to XXI articulation and, in some orders, the formation of a proximal geniculation at the XV to XVI articulation. A proximal geniculation is reported here from the Calanoida for the first time. The geniculations allow the male to grasp the female during any mate guarding and during spermatophore transfer. Particular setae on segments either side of the neocopepodan geniculation are modified as basally fused spines in at least some representatives of the Calanoida, Misophrioida, Cyclopoida, Harpacticoida and Siphonostomatoida. The antennulary chemosensory system, comprising primarily the aesthetascs, is enhanced at the final moult in many male copepods. In planktonic copepods this enhancement may take the form of a doubling of the aesthetascs on almost every antennulary segment, as in the eucalanid calanoids, or of an increase in size of existing aesthetascs, as in the siphonostomatoid Pontoeciella, or of the transformation of possibly originally bimodal, seta-like elements into distally thin-walled, more aesthetasc-like elements, as in some calanoids, harpacticoids and poecilostomatoids. Enhancement of the chemosensory capacity of adult males appears to be linked with their mate-locating role. Copepods inhabiting the open-pelagic water column are more likely to exhibit enhancement of the chemosensory system than neritic or benthic forms. Enhancement may confer a greater sensitivity to chemosensory signals, such as pheromones produced by receptive females, which may retain their directional information at lower concentrations and, therefore, for longer periods, in oceanic waters than in more turbulent neritic waters. Aesthetascs appear to be more evolutionarily labile than other setation elements, apparently being lost and regained within well-defined lineages. Caution is urged in the use of aesthetasc patterns in phylogenetic analysis. The ontogenetic analyses suggest that the timing of expression of intersegmental articulations during development may in future provide the most informative characters for phylogenetic study, rather than either segment numbers or the patterns of fused or undivided segments.

Boxshall, G. A.

1998-01-01

52

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

53

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

54

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

55

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

56

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

57

Diel changes in gut-cell morphology and digestive activity of the marine copepod Acartia tonsa  

Microsoft Academic Search

Morphometric measurements of the gut cells of the marine calanoid copepod Acartia tonsa were made over a 24 h diel cycle to test the hypothesis that feeding rhythms in this copepod are limited by the cycles of blishter-like cells (B-cells) in the gut. Copepods were collected from Long Island Sound, New York, USA, in June 1991. Experimental treatments included low

R. P. Hassett; P. Blades-Eckelbarger

1995-01-01

58

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

59

Rapid Enzymatic Response to Compensate UV Radiation in Copepods  

PubMed Central

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

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

2012-01-01

60

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

61

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

PubMed Central

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

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

2014-01-01

62

Abundance, distribution and patch formation of zooplankton  

NASA Astrophysics Data System (ADS)

The goal of studies described here was to determine the responses of zooplankton taxa to phytoplankton patches which develop in and near intrusions of cold, nutrient-rich Gulf Stream water. To achieve this goal we determined the horizontal and vertical distributions of abundant mesozooplankton taxa on the south-eastern continental shelf of the USA between 29°30? and 31°N. The study period was from June 23 to August 16, 1981. Highest concentrations of zooplankton usually occurred in and near patches of phytoplankton. Increased phytoplankton appeared to trigger the formation of patches of the calanoid copepod Temora turbinata and the cyclopoid copepods Oithona spp. and Oncaea spp. The patches of zooplankton had greater alongshore than cross-shelf dimensions. T. turbinata responded rapidly to increased concentrations of phytoplankton by reproducing and aggregating in and above intruded waters. Oithonidae which were often, but not always, abundant in phytoplankton patches eventually attained high concentrations over most of the middle and part of the inner shelf. Their concentration and that of Oncaeidae increased steadily. Oncaeidae were not abundant in recently upwelled waters, as was T. turbinata but reached high concentrations in older intrusions when the abundance of T. turbinata remained level or decreased slowly. Both cyclopoid taxa are thought to reproduce slowly (egg sacs) compared to T. turbinata. Another taxon, the doliolids, became abundant far more rapidly in intruded waters (by asexual reproduction) than did the other three taxa. Doliolids were the most opportunistic intrusion zooplankton form. They do not regularly occur in low abundance on the shelf, as do the three copepod taxa, but develop in pulses in regions where T. turbinata and Oncaea are not abundant. Of the four taxa studied the abundance of doliolids increased and decreased most rapidly, whereas Oithona and Oncaea increased slowly and did not decrease during the study period. T. turbinata and Oncaea were most abundant at 60% of all stations in the intruding water. Doliolids and Oithona on the other hand, were mostly in the thermocline and intrusion. Whereas phytoplankton patches, which developed in intrusions, were physically induced (PAFFENHÖFER and LEE, 1988), patches of zooplankton were biologically induced.

Paffenhöfer, Gustav-Adolf; Sherman, Byron K.; Lee, Thomas N.

63

Zebra Mussel Dreissena polymorpha  

E-print Network

pseudoharengus Bluespotted Sunfish Enneacanthus gloriosus Amphipod (Gammarid) Gammarus tigrinus Cyclopoid Copepod Diatom Thallassiosira lacustris Starry Stonewort Nitellopsis obtusa Furunculosis Aeromonas salmonicida

64

Temperature impact on reproduction and development of congener copepod populations  

Microsoft Academic Search

The goal of this study was to relate the temperature response of all developmental stages and reproductive biology of two congener copepod pairs inhabiting different biogeographic regions to their geographic distribution patterns. Survival of adult females and egg production, embryonic development and hatching success of the genera Centropages and Temora from two stations, in the North Sea and the Mediterranean,

Claudia Halsband-Lenk; Hans-Jürgen Hirche; François Carlotti

2002-01-01

65

Production and use of copepods in marine fish larviculture  

Microsoft Academic Search

Batch and continuous cultures of the harpacticoid copepod Tisbe holothuriae have been run for numerous generations in the laboratory at the North Sea Centre and the harvested nauplii used as food in preliminary trials with first-feeding turbot (Psetta maxima syn. Scophthalmus maximus). The naupliar swimming behaviour in terms of vertical distribution in a typical fish larval tank and the use

J. G. Støttrup; N. H. Norsker

1997-01-01

66

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

67

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

68

Calanoid Copepods, Feeding Currents, and the Role of Gravity  

Microsoft Academic Search

Feeding currents of free-swimming calanoid copepods, observed through an expanded krypton laser beam and a back-focus dark-field optical system, show that these planktonic animals generate a double shear field to help in detecting food. The interrelation between flow field, perception of food items, and body orientation explains why these animals are generally negatively buoyant.

J. Rudi Strickler

1982-01-01

69

PRIMARY RESEARCH PAPER Variation in calanoid copepod resting egg abundance  

E-print Network

by historical acidification and had compar- atively constant, but different pH over time. We also testedPRIMARY RESEARCH PAPER Variation in calanoid copepod resting egg abundance among lakes this, no other study has described basic characteristics of zooplankton egg banks among lakes

Arnott, Shelley

70

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

PubMed

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. PMID:1060099

Friedman, M M; Strickler, J R

1975-10-01

71

Vertical and temporal distribution of two copepod species, Cyclops scutifer  

E-print Network

Vertical and temporal distribution of two copepod species, Cyclops scutifer and Diaptomus and Diaptomus pribilofensis, in Toolik Lake, Alaska, a site within the Arctic Long Term Ecological Research area temperatures increased. Diaptomus pribilofensis exhibited a strong preference for warmer water and were

California at Santa Barbara, University of

72

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

PubMed Central

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

Friedman, M M; Strickler, J R

1975-01-01

73

DEBATE Open Access Observing copepods through a genomic lens  

E-print Network

genomic tools have transformed many areas of biological and biomedical research, their power to elucidate that will be invaluable in assisting further efforts to provide genomics tools for copepods. Summary: Genomics research , Erica Goetze3 , Stewart C Johnson4 , Carol Eunmi Lee5 and Grace A Wyngaard6 Abstract Background

Lee, Carol Eunmi

74

Some effects of patch food environments on copepods  

Microsoft Academic Search

Laboratory determinations of the time taken for copepods to starve to death and of the effects of discontinuous food availability on egg production are used to demonstrate that different species are adapted to different scales of patchiness in their food environment. Acartia tonsa and Centropages typicus depend on constant food availability and are therefore sensitive to small scales of patchiness,

MICHAEL DAGG

1977-01-01

75

Depth structuring of pelagic copepod biodiversity in waters adjacent to an Eastern Indian Ocean coral reef  

Microsoft Academic Search

We compared pelagic copepod communities at three (400+ m) stations adjacent to Scott Reef (14°S), a shelf-break reef in Australia's Indian Ocean territory, with those within the shallow (c.50 m) atoll lagoon. The metazooplankton assemblage sampled by our 100-?m multinet system was dominated by small (< 1.0 mm) copepods. We identified over 220 copepod species, belonging to five of the nine orders. Of

A. D. McKinnon; S. Duggan; R. Böttger-Schnack; L. F. M. Gusmão; R. A. OLeary

2012-01-01

76

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

77

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

78

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

79

The three-dimensional flow field generated by a feeding calanoid copepod measured using digital holography.  

PubMed

Digital in-line holography is used for measuring the three-dimensional (3-D) trajectory of a free-swimming freshwater copepod Diaptomus minutus, and simultaneously the instantaneous 3-D velocity field around this copepod. The optical setup consists of a collimated He-Ne laser illuminating a sample volume seeded with particles and containing several feeding copepods. A time series of holograms is recorded at 15 Hz using a lensless 2Kx2K digital camera. Inclined mirrors on the walls of the sample volume enable simultaneous recording of two perpendicular views on the same frame. Numerical reconstruction and matching of views determine the 3-D trajectories of a copepod and the tracer particles to within pixel accuracy (7.4 microm). The velocity field and trajectories of particles entrained by the copepod have a recirculating pattern in the copepod's frame of reference. This pattern is caused by the copepod sinking at a rate that is lower than its terminal sinking speed, due to the propulsive force generated by its feeding current. Consequently, the copepod sees the same fluid, requiring it to hop periodically to scan different fluid for food. Using Stokeslets to model the velocity field induced by a point force, the measured velocity distributions enable us to estimate the excess weight of the copepod (7.2x10(-9) N), its excess density (6.7 kg m(-3)) and the propulsive force generated by its feeding appendages (1.8x10(-8) N). PMID:12966057

Malkiel, Edwin; Sheng, Jian; Katz, Joseph; Strickler, J Rudi

2003-10-01

80

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

81

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

82

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...

83

Transport and retention of dormant copepods in the Gulf of Maine  

NASA Astrophysics Data System (ADS)

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

Johnson, Catherine; Pringle, James; Chen, Changsheng

2006-11-01

84

Analysis of the parasitic copepod species richness among Mediterranean fish  

NASA Astrophysics Data System (ADS)

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

Raibaut, André; Combes, Claude; Benoit, Françoise

1998-06-01

85

Increasing Production of Copepod Nauplii in a Brown-Water Zooplankton Culture with Supplemental Feeding and Increased Harvest Levels  

Microsoft Academic Search

Two experiments were performed to investigate increasing the number of copepod nauplii obtained from a brown-water zooplankton culture for feeding to larval red snapper Lutjanus campechanus. Brown-water zooplankton cultures rely on the regular exchange of (brown) estuarine water to nourish and harvest the copepods. The majority of copepods in both experiments were Acartia tonsa. The goal of the first experiment

Jason T. Lemus; John T. Ogle; Jeffrey M. Lotz

2004-01-01

86

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

87

Comparison of Marine Copepod Outfluxes: Nature, Rate, Fate and Role in the Carbon and Nitrogen Cycles  

Microsoft Academic Search

We compare the nature of copepod outfluxes of nonliving matter, the factors controlling their rate and their fate, and finally their role, particularly their relative importance in the carbon and nitrogen cycle. Copepods release dissolved matter through excretion and respiration and particulate matter through production of faecal pellets, carcasses, moults, and dead eggs. Excretion liberates several organic C, N, and

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

2004-01-01

88

Impact of copepod grazing on the red-tide flagellate Chattonella antiqua  

Microsoft Academic Search

Although planktonic copepods are major suspension feeders in the sea, the impact of their grazing pressure upon red-tide flagellates has not been fully investigated. In the present study, the grazing of adult females of several copepod species is examined using three food types: viz. natural suspended particles, natural suspended particles mixed with cultured Chattonella antiqua, and cultured C. antiqua. The

S. Uye

1986-01-01

89

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

90

Performance of Larval Florida Pompano Fed Nauplii of the Calanoid Copepod Pseudodiaptomus pelagicus  

Microsoft Academic Search

The Florida pompano Trachinotus carolinus is a highly prized marine fish species, the larviculture of which currently includes the feeding of live rotifers and nauplii of brine shrimp Artemia spp. However, no previous studies have evaluated the feeding of copepod nauplii. In this study, the growth and survival of Florida pompano larvae fed nauplii of the calanoid copepod Pseudodiaptomus pelagicus

Eric J. Cassiano; Cortney L. Ohs; Charles R. Weirich; Nancy E. Breen; Andrew L. Rhyne

2011-01-01

91

Use of life tables in analyzing the dynamics of copepod populations. [Diaptomus clavipes  

Microsoft Academic Search

The population parameters have been characterized for the generations that developed during a complete reproduction year of a population of the calanoid copepod Diaptomus clavipes Schacht. A model is presented to calculate the numbers of each of the various instars of a copepod produced during any previous interval of time. Life tables were constructed from laboratory data and for the

C. W. Gehrs; A. Robertson

2009-01-01

92

Predation on rotifers by the suspension-feeding Calanoid copepod Diaptomus pallidus  

Microsoft Academic Search

Predation on rotifers by the small suspension-feeding Calanoid copepod Diaptomus pallidus was examined in order to quantify the effects of prey density, prey type, and the presence of algal food resources on ingestion rates, and to determine whether ingested rotifer biomass could be utilized to enhance the survival and reproduction of the copepods. Clearance and ingestion rates of D. pallidus

CRAIG E. WILLIAMSON; NANCY M. BUTLER

1986-01-01

93

PARTIAL PHOTOPERIODIC CONTROL OF DIAPAUSE IN THREE POPULATIONS OF THE FRESHWATER COPEPOD DIAPTOMUS SANGUINEUS  

Microsoft Academic Search

ABSTRACr Populations ofthe freshwater calanoid copepod Diaptomus sanguineus inhabiting three Rhode Island ponds switch from making subitaneous (immediately hatching) to diapausing eggs on different dates. From results of previous research the timing of diapause appears to correspond closely to the individual causes of seasonally harsh conditions in each pond. The results ofrearing copepods from each pond in controlled laboratory environments

NELSON G. HAIRSTON; EMILY J. OLDS

94

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

95

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

96

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

97

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

98

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

99

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

100

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

101

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

102

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

103

Chemical Communication Between Copepods: Finding the Mate in a Fluid Environment  

Microsoft Academic Search

\\u000a Copepods are small heterosexual aquatic microcrustaceans (1–10 mm, moving at ~1–10 bodylengths\\/s) that must mate to reproduce.\\u000a Living in a low Reynolds regime (Re1,000), copepods in some families exhibit an unusual mate-seeking behavior using\\u000a a guidance system not found elsewhere in the animal kingdom. When copepods move through water, they leave a hydrodynamic wake\\u000a whose structure varies with swimming style.

Jeannette Yen; Rachel Lasley

104

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

105

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

106

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

PubMed

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

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

2014-06-01

107

Effects of acute ionizing radiation on selected life stages of the calanoid copepod Diaptomus clavipes schacht  

Microsoft Academic Search

Results are reported from an investigation of the effects of cobalt-60 gamma rays on selected life stages of the calanoid copepod Diaptomus clavipes Schacht following acute doses of ionizing radiation ranging from 0 to 100 krad.

E. A. Bardill; B. G. Blaylock; C. W. Gehrs; J. R. Trabalka

1977-01-01

108

Improving ecological forecasts of copepod community dynamics using genetic algorithms  

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

109

Copepod Aggregations: Influences of Physics and Collective Behavior  

NASA Astrophysics Data System (ADS)

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

Flierl, Glenn R.; Woods, Nicholas W.

2015-02-01

110

Indicator Microorganisms and Pathogens Removal Function Performed by Copepods in Constructed Wetlands  

Microsoft Academic Search

Removal efficiency of indicator and pathogenic microorganisms in constructed wetlands were analyzed, and microorganisms removal\\u000a function performed by copepods was determined. The results showed that the constructed wetlands effectively reduced Escherichia coli, fecal streptococci, total coliforms, and fecal coliforms, the Salmonella spp. removal efficiency was relatively low and the Clostridium perfringens removal was the least. At copepods concentrations of 3.0 × 102\\/L,

Z. W. Song; L. Wu; G. Yang; M. Xu; S. P. Wen

2008-01-01

111

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

PubMed Central

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

Gorb, Stanislav N

2015-01-01

112

Trophic upgrading of food quality by protozoans enhancing copepod growth: role of essential lipids  

Microsoft Academic Search

Protozoa are known for their intermediary trophic role in transferring organic matter from small size planktonic particles\\u000a to mesozooplankton. This study concentrates on the possible addition of biochemical value during this transfer, by new production\\u000a of compounds that are essential in copepod food. In laboratory experiments, copepods could not be raised on a diet of the\\u000a chlorophycean Dunaliella sp., though

W. C. M. Klein Breteler; N. Schogt; M. Baas; S. Schouten; G. W. Kraay

1999-01-01

113

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

PubMed

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

Michels, Jan; Gorb, Stanislav N

2015-01-01

114

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

PubMed

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

115

The use of the copepod Mesocyclops longisetus as a biological control agent for Aedes aegypti in Cali, Colombia.  

PubMed

We present data on the efficacy of Mesocyclops longisetus as a biocontrol agent in controlling Aedes aegypti larvae in catch basins in Cali, Colombia. Additionally, we determined some of the features that facilitated the establishment of the copepods in catch basins. Between June 1999 and February 2000, 201 catch basins were treated with an average of 500 adult copepods. The copepods had established in 49.2% of all the basins and they maintained Ae. aegypti larvae at low densities until the end of the 8-month study. The corrected efficacy percent was 90.4%. The copepods established in basins located in a flat area as opposed to those in steep areas, exposed to sunlight and with 0-10% of floating organic matter. When the catch basins were contaminated with synthetic washing agents, like detergents, the copepods did not survive. The copepod M. longisetus could be incorporated as a biological control agent in an integrated Ae. aegypti control program. PMID:15669381

Suárez-Rubio, Marcela; Suárez, Marco E

2004-12-01

116

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

117

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

PubMed Central

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

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

2014-01-01

118

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...

119

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

120

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

NASA Astrophysics Data System (ADS)

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

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

2008-07-01

121

Evaluating pyrene toxicity on Arctic key copepod species Calanus hyperboreus.  

PubMed

Calanus hyperboreus is a key species in the Arctic regions because of its abundance and role in the Arctic food web. Exploitation of the off shore oil reserves along Western Greenland is expected in the near future, and it is important to evaluate the acute and chronic effects of oil emissions to the ecosystem. In this study C. hyperboreus females were exposed to concentrations of 0, 0.1, 1, 10 and 100 nM pyrene and saturated concentrations measured to ~300 nM. Daily quantification of egg and faecal pellet production showed significant decreases in the pellet production, while the egg production was unaffected. The hatching success was also unaffected, although the total reproductive output was reduced with increased pyrene concentrations. Accumulation of pyrene in the copepods was higher in feeding than starving females and only trace amounts of the phase I metabolite 1-hydroxypyrene, were found. Lowered reproductive output, reduced grazing, and reduced ability to metabolize pyrene suggest that oil contamination may constitute a risk to C. hyperboreus recruitment, energy transfer in the food web and transfer of pyrene to higher trophic levels. PMID:24337827

Nørregaard, Rasmus Dyrmose; Nielsen, Torkel Gissel; Møller, Eva Friis; Strand, Jakob; Espersen, Laila; Møhl, Malene

2014-03-01

122

The lunule of caligid copepods: an evolutionarily novel structure.  

PubMed

Nearly half of the genera of the family Caligidae possess an evolutionarily novel structure called the "lunule" on the ventral surface of the frontal plate. Lunules are paired cup-like suckers that assist in securing attachment of the copepod parasite to its host. Although present in genera such as Caligus and Pseudocaligus, lunules are absent in other caligid genera such as Lepeophtheirus as well as in more primitive caligiforms such as members of the families Trebiidae and Dissonidae. We compared the morphology and development of the anterior margin of the frontal plates between two caligids, Pseudocaligus fugu and Lepeophtheirus sekii, and a more basal caligiform, Dissonus heronensis (a dissonid), using scanning electron, transmission electron, and laser confocal microscopes. Our observations suggest that the lunules originated as a modification of the marginal membranes of the ancestral frontal plates. We also demonstrated the presence of an anlagen cell population for the lunule and marginal membrane in the developing frontal plate. These primordial cells can be detected as early as the first stage of the chalimus phase. Based on these observations, an evolutionary scenario for the lunule is proposed based on cytological evidence. This case study enhances our understanding of "evolutionary novelty," which is a main focus of contemporary evolutionary developmental biology. PMID:23134205

Kaji, Tomonari; Venmathi Maran, B A; Kondoh, Yuusuke; Ohtsuka, Susumu; Boxshall, Geoff A; Tsukagoshi, Akira

2012-01-01

123

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

124

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

125

Density-dependent mortality in an oceanic copepod population.  

PubMed

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

Ohman, M D; Hirche, H J

2001-08-01

126

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

127

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

128

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

2015-03-01

129

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

PubMed

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

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

2014-05-20

130

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

PubMed

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

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

2015-05-01

131

Reading the copepod personal ads: increasing encounter probability with hydromechanical signals  

PubMed Central

Females of the calanoid copepod Temora longicornis react to chemical exudates of male conspecifics with little hops, quite distinct from their normal smooth uniform swimming motion. These hops possibly serve to create a hydrodynamical signal in the surrounding water, to increase encounter probability with potential mates. Laser sheet particle image velocimetry was used to investigate the flow fields associated with these hops and to compare them to the flow of the feeding current of an adult female. During, and immediately after a hop, the flow field around the copepod showed a marked difference from that of a foraging animal. During foraging, the highest velocity gradients were located around the feeding appendages of the copepod. During a hop, high velocity gradients are located behind the animal. About 0.5 seconds after the start of swimming leg movement, effects of the hop had virtually dissipated and the flow field resembled that around a foraging animal. The estimated volume of influence (i.e. the volume around the copepod where the animal has a significant influence on the water) increased about 12-fold during the hop compared with the situation around a foraging animal. Furthermore, the rate of viscous energy dissipation within the copepods' volume of influence increased nearly 80-fold. Hops may serve to increase encounter probability, but due to the short duration of the effect and the high energetic costs they would only be adaptive when other cues have indicated that suitable sexual partners are in the vicinity.

Duren, L. A. van

1998-01-01

132

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...

133

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

134

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

NASA Astrophysics Data System (ADS)

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

Sandulli, R.; Pinckney, J.

1999-05-01

135

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

Microsoft Academic Search

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

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

2009-01-01

136

Identification of the copepod intermediate host of the introduced broad fish tapeworm, Diphyllobothrium latum, in Southern Chile.  

PubMed

The broad fish tapeworm, Diphyllobothrium latum, is an exotic species in both Chile and Argentina, and until now, its copepod host has remained unknown in South American waters. The objective of this study was to identify calanoid copepod species that may be intermediate hosts for D. latum in Lake Panguipulli, Chile. In this lake, the highest levels of infection by this tapeworm occur in the introduced rainbow trout, Oncorhynchus mykiss. Of the 2 calanoid copepods found in Lake Panguipulli, Diaptomus diabolicus and Boeckella gracilipes, only D. diabolicus became infected on experimental exposure to coracidia. Prevalence (mean intensity) of experimental infection in adult copepods was 73.2% (2.8 procercoids per host). Diaptomus diabolicus has been demonstrated to be a new intermediate host; this is the first record of a copepod host for D. latum in South America. PMID:15562630

Torres, P; Villalobos, L; Woelfl, S; Puga, S

2004-10-01

137

Mortalities induced by the copepod Sinergasilus polycolpus in farmed silver and bighead carp in a reservoir.  

PubMed

The frequency distributions of the parasitic copepod Sinergasilus polycolpus were examined in silver carp Hypophthalmichthys molitrix and bighead carp Aristichthys nobilis during a disease outbreak of the 2 species of fish in a reservoir in China. The mean abundance of the copepod was positively related with host length and age, and the overdispersion of the copepod in both silver and bighead carp was fitted well with negative binomial distribution. Although parasite-induced host mortality was observed, a peaked age-parasite abundance curve was not detected in the present parasite-host system. It is also proposed that this peaked age-abundance curve is unlikely to be observed in its natural host populations. PMID:12033711

Wang, Gui T; Li, Wen X; Yao, Wei J; Nie, P

2002-04-01

138

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

PubMed

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

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

2014-12-01

139

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

140

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

141

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

142

Dispersal of Udonella australis (Monogenea: Udonellidae) between caligid copepods Caligus rogercresseyi and Lepeophtheirus mugiloidis on Chilean rock cod.  

PubMed

Udonella australis is a platyhelminth that lives on the surface of the ectoparasite copepods Caligus rogercresseyi and Lepeophtheirus mugiloidis, which coexist on the Chilean rock cod Eleginops maclovinus. The absence of a planktonic oncomiracidium stage in the life cycle of udonellids may limit their dispersal ability. However, the high prevalence and intensity of U. australis on C. rogercresseyi suggest they have developed dispersal strategies to compensate for the lack of a free-living larval stage. The goals of this study were to determine the main dispersal mechanisms of U. australis in 1 copepod species and to compare the dispersal ability of U. australis between 2 different copepod species. Chilean rock cods were infected with female (without udonellids) and male (with and without udonellids) C. rogercresseyi. Other fishes were also infected with this copepod (with U. australis) and with L. mugiloidis (without U. australis). The dispersal of udonellids among copepods occurs through both intraspecific and interspecific processes. The main dispersal mechanism appears to be copepod mating; contact between same-sex individuals is less important. Intraspecific dispersal seems to be more dependent on the number of udonellids per fish than on copepod abundance, as observed for interspecific dispersal. PMID:17539406

Marin, Sandra L; Carvajal, Juan; George-Nascimento, Mario

2007-04-01

143

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

PubMed Central

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

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

2014-01-01

144

Synopsis of lichomolgid copepods (Poecilostomatoida) associated with soft corals (Alcyonacea) in the tropical Indo-Pacific  

Microsoft Academic Search

A synopsis of the 97 species of lichomolgid copepods known to be associated with tropical IndoPacific shallow-water alcyonaceans is given (Madagascar, New Caledonia, Moluccas, Philippines, and Enewetak Atoll). One new genus and 29 new species are included, distributed among the lichomolgid genera Acanthomolgus (2 new species), Alcyonomolgus (1), Colobomolgus (2), Critomolgus (3), Doridicola (5), Paradoridicola (7), Paramolgus (8), and Telestacicola

A. G. Humes

1990-01-01

145

WINTER-TIME DISTRIBUTION AND ABUNDANCE OF COPEPOD NAUPLII IN THE NORTHERN GULF OF MEXICO  

E-print Network

WINTER-TIME DISTRIBUTION AND ABUNDANCE OF COPEPOD NAUPLII IN THE NORTHERN GULF OF MEXICO M. J concentration was correlated with chlorophyll concentration in 4 of 5 comparisons. Maximum concentrations of nauplii (number per m3) within a water column were 2-10 times greater at stations influenced

146

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

PubMed

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

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

2013-11-01

147

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

148

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

149

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

150

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....

151

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

152

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

153

Independent life cycles: an alternative to the asynchronism hypothesis for antarctic Calanoid copepods  

Microsoft Academic Search

Previous analyses of the life cycles and distributions of large antarctic copepods have concluded that competitive exclusion is the most important causal factor. It has been suggested that these species have asynchronous life cycles, their reproduction differing in time as a result of their interspecific interaction. I have analyzed these ideas by studying zooplankton samples collected by six expeditions in

Victor Marin; Alfred Wegener

1988-01-01

154

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...

155

Cross-shelf variation in calanoid copepod production during summer 1996 off the Oregon coast, USA  

Microsoft Academic Search

The fecundity of nine species of adult female calanoid copepods, and molting rates for copepodite stages of Calanus marshallae were measured in 24 h shipboard incubations from samples taken during the upwelling season off the Oregon coast. Hydrographic and chlorophyll measurements were made at approximately 300 stations, and living zooplankton were collected at 36 stations on the continental shelf (150

W. Peterson; J. Gómez-Gutiérrez; Cheryl A. Morgan

2002-01-01

156

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

157

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

158

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

EPA Science Inventory

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

159

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

Microsoft Academic Search

Reproductive strategies of the four congeneric and sympatric calanoid copepods Paraeuchaeta glacialis, P. norvegica, P. barbata, and P. polaris were studied in the Arctic Greenland Sea. Females of all species produce egg sacs and carry their brood attached to the genital opening until the offspring hatch. However, egg size and lipid content as well as clutch size and the fraction

Holger Auel

2004-01-01

160

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

PubMed Central

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

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

2012-01-01

161

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

162

Summer egg production rates of paracalanid copepods in subtropical waters adjacent to Australia's North West Cape  

Microsoft Academic Search

The biological oceanography of waters adjacent to Australia's North West Cape (21° 49' S, 114° 14' E) was studied during the austral summers of 1997\\/98 and 1998\\/99. We measured egg production rate (EPR) by the small paracalanid copepods that dominated the calanoid community. Bottle incubation experiments were conducted at a shallow (~20 m) station in the mouth of Exmouth Gulf,

A. D. McKinnon; S. Duggan

2001-01-01

163

Mechanoreceptors in calanoid copepods: designed for high sensitivity T.M. Weatherbya  

E-print Network

; Scolopidia; Zooplankton 1. Introduction Planktonic organisms inhabit an environment character- ized by a lack of cover, yet an abundance of predators. Many planktonic organisms, including most marine copepods, the sensory environment of these animals is distinct from the more commonly studied arthropods. Behavioral

Lenz, Petra H.

164

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

Microsoft Academic Search

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

JOHN D. COONEY; CARL W. GEHRS

1980-01-01

165

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

SciTech Connect

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

Not Available

1980-05-01

166

Proline biosynthesis genes and their regulation under salinity stress in the euryhaline copepod Tigriopus californicus  

Microsoft Academic Search

Diverse organisms regulate concentrations of intracellular organic osmolytes in response to changes in environmental salinity or desiccation. In marine crustaceans, accumulation of high concentrations of proline is a dominant component of response to hyperosmotic stress. In the euryhaline copepod Tigriopuscalifornicus, synthesis of proline from its metabolic precursor glutamate is tightly regulated by changes in environmental salinity. Here, for the first

Christopher S. Willett; Ronald S. Burton

2002-01-01

167

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

E-print Network

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

Hartline, Daniel K.

168

?-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

169

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

NASA Astrophysics Data System (ADS)

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

Daan, Rogier

170

Horizontal and vertical copepod distribution and abundance on the Mid-Atlantic Ridge in June 2004  

NASA Astrophysics Data System (ADS)

Copepod composition, abundance and distribution were studied in June 2004 on the Mid-Atlantic Ridge, along a transect extending from Iceland (60°N) to the Azores (41°N). The samples were depth-stratified from the surface down to a maximum depth of 2500 m. The transect covered relatively warm and relatively saline Modified North Atlantic Water (MNAW) on the Reykjanes Ridge in the northern part, colder and less-saline Sub-Arctic Intermediate Water (SAIW) further south to the Charlie-Gibbs Fracture Zone (CGFZ), and warm high-salinity North Atlantic Central Water (NACW) in the southern part. In total, 68 copepod genera and 117 species were identified. Calanoid copepods dominated the generic richness with 57 genera. There was a clear increase in the number of genera southwards, from 30 in the northern region to 57 in the south. The total copepod number was variable between stations, ranging from 45,000 to 178,000 m -2; however, the variability did not show any clear north-south trend, and the lowest abundance was observed close to the Sub-Polar Front, located near the CGFZ. Cluster analysis divided the transect into three main regions as based on copepod community structure: one in the northern part (containing MNAW and SAIW) where Calanus finmarchicus and Pareuchaea tonsa characterized the region; one in the Frontal Region (SAIW/NACW) where C. hyperboreus was more abundant than in the other two regions and one southern region (containing NACW), characterized by several species, e.g., Calanus helgolandicus, Mecynocera clausi and Pleuromamma gracialis. Vertically, the copepods mainly occurred in the upper part of the water column. In total, 53% of the individuals occurred above 100 m and 75% above 500 m depth. Below 1000 m depth, only low numbers were recorded (˜10% of the total copepod abundance). There were large differences in vertical distribution between genera/species, with M. clausi, Acartia spp. and Pseudocalanus spp. showing the shallowest distribution and Oncaea spp., Pleuromamma spp. and Microcalanus spp. the deepest distribution. Depth distribution, however, was also affected by hydrographic differences between stations. In the deepest samples, there was a tendency for a higher total abundance close to the bottom than at greater distances from bottom.

Gaard, E.; Gislason, A.; Falkenhaug, T.; Søiland, H.; Musaeva, E.; Vereshchaka, A.; Vinogradov, G.

2008-01-01

171

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

172

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

173

Meningeal-like organization of neural tissues in calanoid copepods (Crustacea).  

PubMed

Meninges, the connective tissue of the vertebrate central nervous system (CNS), have not been recognized in invertebrates. We describe the ultrastructure of the adult brain, antennules, and cord in five marine copepods: Calanus finmarchicus, Gaussia princeps, Bestiolina similis, Labidocera madurae, and Euchaeta rimana. In all of these locations we identified cell types with characteristics of the typical cells of vertebrate meninges and of their peripheral nervous system (PNS) connective tissue counterpart: fibroblasts, having flattened twisting processes with labyrinthine cavities communicating with the extracellular space, and macrophages, containing prominent lysosomes, well-developed endoplasmic reticulum, Golgi apparatus, and indented heterochromatin. The vertebrate distinction between electron-dense cells 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 copepod CNS and PNS. Similar to the vertebrate organization, electron-dense cell networks penetrated from the outer layer (subcuticle) to surround inner substructures of the copepod nervous systems, and electron-lucent networks penetrated deeply from the brain and nerve surfaces to form intertwined associations with neural cells. Moreover, the association of these cells with basement membranes, glycocalyx, and fibrils of collagen in copepods conforms to a meningeal organization. The primary deviation from the vertebrate ultrastructural organization was the often tight investment of axons by the meningeal-like cells, with an intercalated basement membrane. Together, these data suggest that the tissues investing the copepod nervous system possess an organization that is analogous in many respects to that of vertebrate meninges. PMID:22740424

Mercier, Frederic; Weatherby, Tina M; Hartline, Daniel K

2013-03-01

174

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

175

Physiological effects of copper in the euryhaline copepod Acartia tonsa: waterborne versus waterborne plus dietborne exposure.  

PubMed

The physiological effects of waterborne and waterborne plus dietborne copper exposure were determined in the euryhaline copepod Acartia tonsa at different salinities (5, 15 and 30ppt). Copepods were exposed (48h) to a reported 48-h LC50 for copper (CuCl(2)), which had been previously determined under the same experimental conditions. Whole body copper accumulation, ion concentrations (Na(+), Cl(-), Mg(2+)), and Na(+), K(+)-ATPase activity were the endpoints measured in all experimental groups. Feeding rate was also measured in fed experimental groups. In copper-exposed copepods, whole body copper accumulation was dependent on salinity, decreasing as salinity increased. However, it was similar in copepods exposed to waterborne and waterborne plus dietborne copper, irrespective the salinity tested. Waterborne copper exposure induced a disturbance of the whole body Na(+) concentration in all salinities tested. This effect was characterized by an increased whole body Na(+) concentration in seawater (salinity 30ppt) and a decreased whole body Na(+) concentration at lower salinities (5 and 15ppt). The ionoregulatory imbalance in low salinity (5ppt) was associated with an inhibition of the whole body Na(+), K(+)-ATPase activity, as observed in freshwater fish and crustaceans. When copepods were exposed to waterborne plus dietborne copper, the physiological effects described were only observed at a low salinity (5ppt) and were associated with a marked inhibition of the feeding rate. Taken altogether, the data suggest that the physiological effects induced by waterborne copper exposure in A. tonsa acclimated to higher salinities (15 and 30ppt) are due to a combined effect of food restriction and copper exposure. Differential physiological responses to waterborne and waterborne plus dietborne copper cannot be ascribed to differences in whole body copper burden. PMID:17659357

Pinho, Grasiela Lopes Leães; Pedroso, Mariana Saia; Rodrigues, Sandra Carvalho; Souza, Sandra Silvestre de; Bianchini, Adalto

2007-08-15

176

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

PubMed

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

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

2014-01-01

177

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

178

Ciliate epibiont effects on feeding, energy reserves, and sensitivity to hydrocarbon contaminants in an estuarine harpacticoid copepod  

Microsoft Academic Search

Although epibiotic protozoans are commonly observed on the chitinous exoskeleton of aquatic crustaceans, relatively little\\u000a is known about their ecological significance. The significance of protozoan epibionts on benthic copepods has never been examined.Coullana sp., a meiobenthic harpacticoid copepod, is abundant in Louisiana salt marshes and has high incidence (?50%) of ciliate epibionts.\\u000a Field and laboratory grazing experiments indicated that ciliate

Gwyn L. Puckett; Kevin R. Carman

2002-01-01

179

Oxygen consumption rates of fecal pellets produced by three coastal copepod species fed with a diatom Thalassiosira pseudonana  

Microsoft Academic Search

Fecal pellet production rate and oxygen consumption rate of copepod fecal pellets egested by Paracalanus sp., Acartia spinicauda and Centropages orsinii feeding on a diatom Thalassiosira pseudonana were measured. Fecal pellet production rates varied between 3.6 and 80.6 pellets ind?1d?1 among three species, with fecal pellet production of Paracalanus sp. significantly higher than the other two copepod species. Average pellet

Loklun Shek; Hongbin Liu

2010-01-01

180

Feeding, Respiration and Excretion of the Copepod Calanus hyperboreus from Baffin Bay, Including Waters Contaminated by Oil Seeps  

Microsoft Academic Search

Metabolic processes in eastern arctic copepods Culunus hyperboreus were analyzed during the post-bloom period (August-September). Mixed adult and subadult copepods were collected from 12 stations in Baffin Bay (Davis Strait to Lancaster Sound) by trawling from 0-300 m. Measurements were made of clearance rate, 02-consumption and NH3 excretion. The cruise track included 6 stations in oil-seep contaminated waters of Scott

EDWARD S. GILFILLAN; JOHN H. VANDERMEULEN

1986-01-01

181

First record in Mediterranean Sea and redescription of the bentho-planktonic calanoid copepod species Pseudocyclops xiphophorus Wells, 1967  

NASA Astrophysics Data System (ADS)

The bentho-planktonic calanoid copepod Pseudocyclops xiphophorus Wells, 1967, previously recorded only in coastal waters of Mozambique, has been found in the brackish Lake Faro (eastern Sicily, central Mediterranean). The copepods were collected from fouling attached to submerged mooring posts and ropes in the Lake. Both sexes of P. xiphophorus are redescribed. This interesting zoogeographic distribution suggests that the Mozambican and Mediterranean Pseudocyclops populations exhibit a complete Tethyan pattern.

Zagami, Giacomo; Costanzo, Giuseppe; Crescenti, Nunzio

2005-03-01

182

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

NASA Astrophysics Data System (ADS)

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

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

1990-12-01

183

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

184

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

Microsoft Academic Search

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

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

2010-01-01

185

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

186

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

NASA Astrophysics Data System (ADS)

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

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

2004-11-01

187

Stable isotopic compositions of overwintering copepods in the arctic and subarctic waters and implications to the feeding history  

NASA Astrophysics Data System (ADS)

Highly abundant zooplankton dominated by copepods was found in the upper 200 m water column off the west of Spitsbergen in winter, although copepods in high-latitude environments during the overwintering period are known to reside in deep waters. We examined the possible feeding activities of these surface dwelling, overwintering copepods through their stable isotope compositions ( ?15N and ?13C), and their internal lipids. The differences in the ?15N values ( ?15N enrichment factor) between the particulate organic matter (POM) at the surface layers and the dominant copepods in winter showed that the averaged ?15N enrichment factor in Calanus glacialis (+2.7‰) and Metridia longa (+2.8‰) were higher than that in Calanus finmarchicus (+1.7‰). This suggests that C. glacialis and M. longa might be occasional omnivorous feeders, because the ?15N enrichment factor of these two copepods were relatively close to the previously reported value (e.g. +3.4±1.1‰, [Geochim. Cosmochim. Acta 48 (1984) 1135]) for a stepwise increase of the value with the food chain. The estimated lipid isotopic ratios ( ?13C) of C. finmarchicus and M. longa tended to decrease with the decreasing lipid contents (lipid carbon/total carbon), suggesting that some lipid components with heavy isotopes were removed from the total lipids. The isotopic changes of lipids with the lipid contents probably reflect the metabolic processes of lipid utilization of arctic and subarctic copepods during the overwintering period.

Sato, Megumi; Sasaki, Hiroshi; Fukuchi, Mitsuo

2002-12-01

188

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

SciTech Connect

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

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

1980-04-01

189

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

PubMed

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

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

2015-03-01

190

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

191

[Copepods distribution in relation to a Cape Ghir upwelling filament (Moroccan Atlantic coast)].  

PubMed

The study of the Cape Ghir upwelling filament (31°N) focalizes to describe the dispersive mechanism, caused by the upwelling. The zooplankton was sampled during five oceanographic cruises conducted between 2008 and 2009. Surface temperature and chlorophyll "a" were also measured along with sampling. The distribution of environmental parameters accused extensions that show the path of the filament. Copepods constitute the largest fraction of zooplankton community and represented by 86 species, majorly dominated by Acartia clausi and Oncaea venusta. A number of species of deep or cold waters have been recorded in the area corresponding to a net resurgence of cold water. The analysis of the copepods distribution allowed to view the path of the filament at different times of the year. The distribution of the species A. clausi, neritic specie was observed in the open ocean, shows a result of this dynamic. PMID:22325569

Salah, Siham; Ettahiri, Omar; Berraho, Amina; Benazzouz, Aïssa; Elkalay, Khalid; Errhif, Ahmed

2012-02-01

192

First principles of copepod development help explain global marine diversity patterns.  

PubMed

A major goal of modern ecology is to understand macroecological patterns based on their mechanistic underpinnings. The metabolic theory of ecology predicts a monotonic increase of biodiversity with temperature based on the principles of metabolism. For marine copepods, observations have shown that while biodiversity does increase with temperature, the theory's prediction overestimates the slope of this relationship by a factor of two. By relaxing the theory's assumption that size is invariant with respect to temperature, and by incorporating a mechanistic description of copepod development into the theory, we provide an adjusted prediction that agrees with the observed relationship. The addition of development into the theory adds the potential to refine the prediction for a wider range of taxa, to account for discrepancies between prediction and observations, and to describe a wider variety of temperature-richness relationships. PMID:22476710

Record, Nicholas R; Pershing, Andrew J; Maps, Frédéric

2012-10-01

193

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

194

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

195

Interactions between two closely related phytal harpacticoid copepods, asymmetric positive and negative effects  

Microsoft Academic Search

Competition for food is generally thought to exert a strong evolutionary pressure, driving trophic niche separation, either by specialization and\\/or by widening the choice of potential food resources. Harpacticoid copepods are common inhabitants of phytal assemblages, where several closely related species of the so-called phytal dwelling families often co-occur. However, direct competition among phytal harpacticoids has been thought to be

Nina Larissa Arroyo; Katri Aarnio; Emil Ólafsson

2007-01-01

196

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

Microsoft Academic Search

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

R. F. Lee

1974-01-01

197

Microbial decomposition of proteins and lipids in copepod versus rotifer carcasses  

Microsoft Academic Search

Zooplankton carcasses are common within aquatic systems and potentially serve as organic-rich substrates for bacteria. We\\u000a compared the microbial decomposition of representative crustacean (copepod) and non-crustacean (rotifer) zooplankton carcasses\\u000a and monitored changes in carcass protein and lipid contents. Our results showed that carcass decomposition was mainly driven\\u000a by bacteria colonizing from the surrounding water. Carcass-associated bacteria displayed higher protease and

Samantha L. BickelKam; Kam W. Tang

2010-01-01

198

Ingestion, fecundity, growth rates and culture of the harpacticoid copepod, Tisbe furcata, in the laboratory  

Microsoft Academic Search

The ingestion, fecundity, growth rates and culture of theharpacticoid copepod, Tisbe furcata, fed different algalspecies at different cell densities were studied. It was foundthat Tisbe furcata initiated feeding at an algalconcentration of 2.5 cells µl-1 for Rhinomonasreticulata and 8 cells µl-1 for Skeletonemacostatum but a higher concentration of 30 cells µl-1was needed for the flagellate, Pavlova lutheri. Althoughthe larval growth

Tawfiq S. Abu-Rezq; A. B. Yule; S. K. Teng

1997-01-01

199

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

PubMed Central

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

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

2010-01-01

200

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

Microsoft Academic Search

Ecdysteroids are steroid hormones that play an important role in development, growth, molting of larva, and reproduction in the Arthropoda. The effect of ecdysteroids is mediated by its binding to ecdysteroid receptor (EcR). To investigate the role of EcR during development and the effect to environmental stressors on EcR expression in a copepod, we isolated and characterized cDNA and 5?-promoter

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

2010-01-01

201

Phylogeography of the copepod Acartia hudsonica in estuaries of the northeastern United States  

Microsoft Academic Search

Copepods of the genus Acartia dominate zooplankton assemblages in northwestern Atlantic estuaries, many of which originated after the last glacial maximum\\u000a 10,000–18,000 years ago. Acartia hudsonica occurs, at least seasonally, in estuaries from Chesapeake Bay to Labrador\\/Newfoundland. We sequenced the mitochondrial gene\\u000a Cytochrome B (CytB) of 75 individuals of A. hudsonica from 26 estuaries from New Jersey to Maine, covering four

Peter J. Milligan; Eli A. Stahl; Nikolaos V. Schizas; Jefferson T. Turner

2011-01-01

202

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

203

New records of parasitic copepods (Crustacea, Copepoda) from marine fishes in the Argentinean Sea.  

PubMed

Increasing knowledge of the biodiversity of parasitic copepods in the Argentinean Sea will provide a baseline against which changes in the distribution of marine biota can be detected. We provide new information on the distribution of 13 known species of parasitic copepods gathered from 11 species of marine fishes from Argentinean Sea, including 7 new host records and 9 new locality records. These species are: Bomolochus globiceps (Vervoort et Ramírez, 1968) and Nothobomolochus cresseyi Timi et Sardella, 1997 (Bomolochidae Sumpf, 1871); Brasilochondria riograndensis Thatcher et Pereira, 2004 (Chondracanthidae Milne Edwards, 1840); Taeniacanthus lagocephali Pearse, 1952 (Taeniacanthidae Wilson, 1911); Caligus rogercresseyi Boxshall et Bravo, 2000 and Metacaligus uruguayensis (Thomsen, 1949) (Caligidae Burmeister, 1835); Hatschekia conifera Yamaguti, 1939 (Hatschekiidae Kabata, 1979); Clavellotis pagri (Krøyer, 1863), Clavella adunca (Strøm, 1762), Clavella bowmani Kabata, 1963 and Parabrachiella amphipacifica Ho, 1982 (Lernaeopodidae Milne Edwards, 1840), and Lernanthropus leidyi Wilson, 1922 and Lernanthropus caudatus Wilson, 1922 (Lernanthropidae Kabata, 1979). A list of host species lacking parasitic copepods, for which large samples were investigated by the authors, is also provided in order to compare in future surveys. PMID:22807018

Paula, Cantatore Delfina María; Elizabeth, Braicovich Paola; Julia, Alarcos Ana; Laura, Lanfranchi Ana; Alejandra, Rossin María; Gustavo, Vales Damián; Tomás, Timi Juan

2012-03-01

204

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

PubMed

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 degrees C) than at the cooler temperature (6 degrees 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

205

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

PubMed

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

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

2013-12-17

206

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

PubMed

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

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

2011-05-01

207

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

PubMed

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

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

2015-03-17

208

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

209

The Northeast Water Polynya during summer 1992: Distribution and aspects of secondary production of copepods  

NASA Astrophysics Data System (ADS)

Zooplankton ecology in the Northeast Water Polynya was investigated from July 15 to August 15, 1992. The initial hypotheses were that the polynya would be a site of enhanced secondary production and that the copepod community would be composed of varying proportions of North Atlantic and Arctic species advected onto the Greenland shelf through the Northern and Southern Troughs. Striking contrasts were observed between the northern and southern regions of the shelf. The southern region was dominated numerically by the North Atlantic species Calanus finmarchicus, while species of Arctic origin (C. glacialis, C. hyperboreus, Metridia longa) dominated in the northern region. The polynya itself contained few of the herbivorous Calanus species but, instead, was dominated by the omnivore M. longa. Secondary production of C. glacialis, represented by egg production rates, was high in all regions (55-88 eggs/female/day). However, because of low abundances of the large bodied Calanus species within the polynya, it is estimated that the herbivorous copepods were not significant consumers of primary production in the polynya. Fundamentally different pathways for the cycling of carbon may exist in the northern and southern regions. Copepod communities may utilize much of the primary production in the south but only a small proportion of the primary production in the polynya, where significant proportions may be unconsumed.

Ashjian, Carin J.; Smith, Sharon L.; Lane, Peter V. Z.

1995-03-01

210

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

PubMed Central

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

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

2013-01-01

211

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

212

Influence of projected ocean warming on population growth potential in two North Atlantic copepod species  

NASA Astrophysics Data System (ADS)

Copepods of the genera Pseudocalanus and Centropages play an important role in the North Atlantic ecosystems and have distinctive spatial and temporal patterns depending on physiological adaptation to different environmental conditions. To examine the possible impact of climate change on these biogeographic patterns, potential population growth rate was computed for each species using IPCC projections of sea surface temperature together with chlorophyll distributions from SeaWiFS climatology and published laboratory data on temperature and food-dependent life-history parameters. The results indicate that the predicted temperature increase throughout the North Atlantic will cause temporal and spatial shifts in copepod species population growth potential. The Centropages population is projected to increase in mid-latitudinal shelf areas, e.g. the Gulf of Maine and the North Sea, due to shorter generation times and a longer growing season, while Pseudocalanus is predicted to be less abundant in these regions after 2050. These shifts potentially have a significant impact on the future demographics of pelagic fish species for which the copepods are the major food source.

Stegert, Christoph; Ji, Rubao; Davis, Cabell S.

2010-10-01

213

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

214

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

PubMed

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

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

2006-03-01

215

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

PubMed Central

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

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

1998-01-01

216

Distribution and importance of wax esters in marine copepods and other zooplankton  

NASA Astrophysics Data System (ADS)

Zooplankton were captured for detailed lipid analyses from known depth intervals in opening-closing nets and in midwater trawls to 2500m at a station in the subtropical Pacific. Copepods were also collected from the upper 500 m of a second subtropical and a temperate station in the Pacific, and a station in the Arctic. At the subtropical station wax esters were a minor part of the total lipid (less than 10%) and triglycerides were the most important lipid of many copepods inhabiting the upper 325 m, whereas wax esters were the main lipid constituent (over 50% of the lipid) and triglycerides were a minor lipid component for all copepods examined from depths below 625 m. The 325-625 m depth interval appeared to be a transition zone. Wax esters also comprised over 40% of the lipid in most of the temperate and polar calanoids examined. Triglycerides tended to be replaced by wax esters as the main lipid component in copepods from deep water or cold water. All genera examined belonging to the families Calanidae, Euchaetidae, Lucicutiidae, Heterorhabdidae, and Augaptilidae had greater than 20% of their lipid as wax esters. The genera examined from these families generally occur in deep water or near-surface cold waters. Members of the families Candaciidae and Pontellidae contained less than 10% wax ester. They are primarily found at shallow depths from tropical to temperate waters. The families Eucalanidae, Aetideidae, Scolecithtricidae, and Metridiidae contained genera with varying amounts of wax esters. These families have both genera and species which inhabit various depth and temperature ranges. Experiments on the rate of lipid utilization for periods up to one week generally showed a slow decrease in the percentage lipid of the dry weight. Detailed lipid analysis of Gaussia princeps during starvation showed triglyceride was utilized while wax esters remained relatively unchanged. The depth and latitudinal distribution of lipid in marine copepods may generally be explained on the basis of temperature or the temporal distribution, relative abundance, and rate of supply of food. However, there some exceptions, and the importance of taxonomic affinity cannot be ignored.

Lee, Richard F.; Hirota, Jed; Barnett, Arthur M.

217

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

218

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

NASA Astrophysics Data System (ADS)

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

Gowing, Marcia M.; Wishner, Karen F.

1986-07-01

219

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

PubMed Central

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

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

2014-01-01

220

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

221

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

222

Effects of food quality on growth and biochemical composition of a calanoid copepod, Argyrodiaptomus furcatus , and its importance as a natural food source for larvae of two tropical fishes  

Microsoft Academic Search

Growth, reproduction and biochemical composition were analyzed for the copepod Argyrodiaptomus furcatus fed on the alga Ankistrodesmus gracilis grown in different media. The ingestion of this copepod by larvae of two species of tropical fishes was also evaluated. The mean peak density of the copepod population was 1369 individuals 1-1 for all four diets used, and the highest was 1387

Lúcia Helena Sipaúba-Tavares; Maria Adriana Bachion; Francisco Manoel de Souza Braga

223

Effects of food quality on growth and biochemical composition of a calanoid copepod, Argyrodiaptomus furcatus, and its importance as a natural food source for larvae of two tropical fishes  

Microsoft Academic Search

Growth, reproduction and biochemical composition were analyzed for the copepod Argyrodiaptomus furcatus fed on the alga Ankistrodesmus gracilis grown in different media. The ingestion of this copepod by larvae of two species of tropical fishes was also evaluated. The mean peak density of the copepod population was 1369 individuals l-1 for all four diets used, and the highest was 1387

Lúcia Helena Sipaúba-Tavares; Maria Adriana Bachion; Francisco Manoel de Souza Braga

2001-01-01

224

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  

Microsoft Academic Search

Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that\\u000a 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

Guangxing Liu; Donghui Xu

2009-01-01

225

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

226

Seasonality of parasitic copepods on bullseye puffer, Sphoeroides annulatus (Pisces: Tetraodontidae), from the northwestern coast of Mexico.  

PubMed

Seasonal occurrence of parasitic copepods in wild bullseye puffer, Sphoeroides annulatus (Pisces: Tetraodontidae), was analyzed in conjunction with variation of biotic and abiotic factors. Eleven samples were taken between February 2007 and February 2008 in Santa María La Reforma lagoon (northwestern coast of México). In total, 337 fish was examined; 5 parasitic copepod species were observed, including Acantholochus zairae , Caligus serratus , Lepeophtheirus simplex , Pseudochondracanthus diceraus , and Parabrachiella sp. The most common species were L. simplex , P. diceraus, and C. serratus (overall prevalence, 59, 53, and 35%, respectively), which significantly varied in prevalence and mean intensity between sampling months. A seasonal pattern was only observed for L. simplex, with higher infection levels in the warmest month than in the coldest month. Statistical analyses indicated that the intensity of L. simplex was positively correlated with water temperature. There were no significant differences in prevalence and intensity of infection among female and male hosts. At the component community level, species richness ranged between 4 and 5 during most of the study period, and no seasonality was observed in the number of individuals, Shannon diversity index, evenness index, or the Berger-Parker dominance index. At the infracommunity level, 4 descriptors used (mean species richness, mean number of individuals, mean Brillouin's diversity index, and mean Berger-Parker index) varied significantly between sampling months, but no seasonality was observed, except for a slight increase in the number of individuals during the warmest month. A significant positive association was detected between number of individuals and water temperature and between host size and both species richness and number of individuals. This is the first account of the ecology of these 5 parasitic copepods. Although no significant association was detected between fish condition factor and the burden of parasitic copepods, given the high occurrence of the caligid copepod L. simplex , we suggest that this copepod could represent a threat for the culture of S. annulatus . PMID:21506849

Morales-Serna, Francisco Neptalí; Rubio-Godoy, Miguel; Gómez, Samuel

2011-08-01

227

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

228

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

229

The copepod fauna of the Gulf of Carpentaria, and its Indo-West Pacific affinities  

NASA Astrophysics Data System (ADS)

Copepods from the Gulf of Carpentaria, the tropical, northern Australian waters adjacent to the Arafura Sea, were collected from 23 sites spanning the entire Gulf during 10 cruises in the period August 1975 to May 1977. Samples were taken using plankton nets with mesh size of 142 ?m. One hundred and two species of copepods were identified, 68 species belonging to the sub-order Calanoida, 30 to the Cyclopoida and four to the Harpacticoida. Thirteen of these species were new to science; descriptions of seven have so far been published. Ninety five of the species collected in this study are new records for the Gulf region, and 23 are new records for waters of the Australian continent. The faunal composition is characteristically warm water neritic, and shows similarity to that of Southeast Asia, having at least 88 species in common. Comparisons of copepod species records from the Gulf of Carpentaria with those from the northeastern Pacific coast of Australia (Great Barrier Reef and Moreton Bay) show 79 species to be common to these areas. Of all the species collected in the Gulf, three have been previously recorded from the Indian Ocean but not the Pacific, and five are otherwise only known from the Pacific Ocean. The Gulf is regarded as forming the southeasternmost region of the Indo-pacific marine domain, within which most of the 13 new species encountered in this study appear to be endemic. Species distribution patterns are discussed in relation to post-glacial and present-day hydrodynamics of the region.

Othman, B. H. R.; Greenwood, J. G.; Rothlisberg, P. C.

230

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

Microsoft Academic Search

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

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

2003-01-01

231

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

SciTech Connect

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

Kusk, K.O.; Wollenberger, L.

1999-07-01

232

A preliminary study of the distribution of some copepods in upper Laguna Madre  

E-print Network

protected waters. Its abundance tended to repeat in a general way from year to year. Deevey also noted that salinity in the area varied nnly about 3;, o but stated that even this small change showed 'mportant effects on the plankton community... of the differences between stations and tr'ps. Acartia tonsa was generally the most abundant species of copepod found, being present in every plankton tow throughout the survey. The number per cubic meter in each tow was compared to chlorinity (from Table III...

Henderson, John C

1958-01-01

233

Wax ester biosynthesis in calanoid copepods in relation to vertical migration  

NASA Astrophysics Data System (ADS)

Lipid analyses of Calanus fimmarchicus caught at different depths of the North Sea during the night hours of late May to early June reveal that the % total lipid tends to be positively correlated with depth. An assay for the biosynthesis of wax esters in calanoid copepods is described. Application of this assay under field conditions has shown that during the night in late May to early June the rate of wax ester biosynthesis in C. finmarchicus and Acartia sp. tends to be negatively correlated with depth. The results are discussed in terms of vertical migration of calanoids.

Gatten, R. R.; Sargent, J. R.

234

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

PubMed

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

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

2015-04-01

235

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

PubMed

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

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

2010-12-01

236

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

PubMed

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

Thor

2000-03-15

237

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

238

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

PubMed

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

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

2013-01-01

239

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

PubMed

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

2013-09-01

240

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

NASA Astrophysics Data System (ADS)

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

Dvoretsky, Vladimir G.; Dvoretsky, Alexander G.

2014-09-01

241

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

242

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

243

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

Microsoft Academic Search

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

Sharon L. Smith

1991-01-01

244

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

245

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

246

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...

247

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...

248

Calanoid copepods assemblages in Pearl River Estuary of China in summer: Relationships between species distribution and environmental variables  

NASA Astrophysics Data System (ADS)

To study the relationships between species distribution and environmental variables, calanoid copepods were classified and enumerated, and environmental variables were analyzed along 91 sites of the Pearl River Estuary (China) and adjacent waters. The 91 sites were divided into 3 groups based on surface salinity: the Inner area had salinity level below 10‰ and was mostly located in the Pearl River Estuary, the Coastal area had salinity between 10‰ and 32‰ and was almost located along the coastline, while the Offshore area had salinity level higher than 32‰ and was mainly located in the open area. Indicator Species Analysis was conducted to identify the indicator species within each group from among all calanoid copepods taxa. We found that the Inner area was characterized by Acartiella sinensis, Pseudodiaptomus poplesia and Pseudodiaptomus inopinus, the coastal area was characterized by Temora turbinata and Subeucalanus subcrassus, and the Offshore area was characterized by Paracandacia truncata, Subeucalanus subtenuis, Euchaeta rimana, Pareucalanus attenuatus, Rhincalanus cornutus, Cosmocalanus darwini, Centropages gracilis, Undinula vulgaris, Nannocalanus minor and Paraeuchaeta russelli. Canonical Correspondence Analysis (CCA) was used to identify relevant biotic and abiotic parameters that can best explain the distribution of calanoid copepods. CCA showed that during the summer of 2006, salinity, nutrient variables, especially SiO 3-Si, NO 3-N and DTN, Depth and Chl a were the environmental variables that strongly impacted the distribution and community structure of calanoid copepods.

Lin, Duan; Li, XiuQin; Fang, HongDa; Dong, YanHong; Huang, ZhuoXuan; Chen, JiaHui

2011-07-01

249

The risk of parasite transfer to juvenile fishes by live copepod food with the example Triaenophorus crassus and Triaenophorus nodulosus  

Microsoft Academic Search

Natural zooplankton is a potential food resource for juvenile fish in fish farms as it is a good source of fats, carbohydrates, and protein. However, it is also a potential source of parasites and pathogens. The present study was conducted (1) to estimate the risk of parasite transfer by live copepod food under intensive farming conditions using the parasites Triaenophorus

Franz Lahnsteiner; Manfred Kletzl; Thomas Weismann

2009-01-01

250

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

251

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...

252

Predator-prey interactions between omnivorous diaptomid copepods and rotifers: The role of prey morphology and behavior  

Microsoft Academic Search

Suspension-feeding diaptomid copepods feed selectively on several rotifer species. Predator-prey interactions between Diaptomus pallidus and seven species of rotifers were quantified and behav- ioral probabilities computed. Prey size was a good predictor of the probability of Diaptomus avoiding a prey following an encounter but had little or no predictive value in subsequent levels of interaction (capture, ingestion). Three of the

CRAIG E. WILLIAMSON

1987-01-01

253

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

254

On the lipid biochemistry of polar copepods: compositional differences in the Antarctic calanoids Euchaeta antarctica and Euchirella rostromagna  

Microsoft Academic Search

During austral summer of 1985 different developmental stages (CIII, CIV, CV, females, males) of the Antarctic copepod Euchaeta antarctica and females of Euchirella rostromagna were collected in the southeastern Weddell Sea to determine their lipid contents and compositions. For E. antarctica the analyses revealed a strong ontogenetic accumulation of lipids towards the older copepodids with highest lipid contents in late

W. Hagen; G. Kattner; M. Graeve

1995-01-01

255

Effects of temperature and nutritional state on the acute toxicity of acridine to the calanoid copepod, Diaptomus clavipes Schacht  

Microsoft Academic Search

Acute toxicity tests were performed on adult males and females of a freshwater calanoid copepod, Diaptomus clavipes Schacht, using the azaarene acridine as the test compound. Tests were performed at three temperatures (16, 21 and 26°C) and over a range of nutritional states (fed, starved and stock). Observations on mortality were made at 24-h intervals for 96 h. Analysis of

John D. Cooney; John J. Beauchamp; Carl W. Gehrs

1983-01-01

256

Acetylcholinesterase activity in copepods (Tigriopus brevicornis) from the Vilaine River estuary, France, as a biomarker of neurotoxic contaminants  

Microsoft Academic Search

From April 1997 to June 1998, 14 measurements of acetylcholinesterase (AChE) enzymatic activity were performed with the copepod, Tigriopus brevicornis, collected at five stations in the Vilaine River estuary (South Brittany, France). Simultaneously, four chemical analyses of triazines and one analysis of total pesticides in water were undertaken. AChE activity levels in T. brevicornis were compared to the levels measured

B. Beliaeff

257

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

258

EFFECTS OF DIET ON GROWTH AND SURVIVAL OF LARVAL WALLYES  

EPA Science Inventory

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

259

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...

260

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

261

Sinergasilus polycolpus, a new copepod species in the ichthyoparasitofauna of Serbia and Montenegro.  

PubMed

The parasitic copepod Sinergasilus polycolpus was identified on the gills of bighead carp Aristichthys nobilis from 2 localities (Kladovo and Slankamen) in the Serbian part of the River Danube. This parasite is species-specific for 2 Chinese carp, the bighead carp and the silver carp Hypophthalmichthys molitrix. It was accidentally introduced into Serbia and Montenegro together with fry of these herbivorous carp intended for aquaculture and control of phytoplankton blooms. There is no record in the available literature of this parasite for European freshwaters. Our identification of S. polycolpus signals the possible spread of the infectious disease sinergasilosis in natural freshwaters and in fishponds, similar to bothriocephalosis, caused by Bothriocephalus opsariichthydis, which was introduced with the fry of various herbivorous species from the Amour River basin (USSR) into almost all countries throughout the world. PMID:15109152

Cakic, P; Lenhardt, M; Kolarevic, J

2004-03-10

262

Parasitic copepods of the common sole, Solea solea (L.), from the Eastern Mediterranean coast of Turkey.  

PubMed

There is increasing interest in the common sole, Solea solea (Linnaeus), as an alternative fish species in aquaculture in the Mediterranean region, and parasitic copepods are a potential hazard for farmed finfish. This paper provides taxonomic information on two species of sea lice (family Caligidae) collected from S. solea in eastern Mediterranean waters off the Turkish coast. Caligus brevicaudatus A. Scott, 1901 and Caligus apodus (Brian, 1924) were both found and this is the first report of C. brevicaudatus in Turkish waters. The discovery of C. apodus on S. solea is a new host record. Key diagnostic characters of both species are reported, supported by light and scanning electron microscopy observations. During a 12-month survey a prevalence of 28% was recorded for C. brevicaudatus, whereas for C. apodus peak prevalence was much lower (3%). PMID:24048749

Özak, Argun Akif; Demirkale, Ibrahim; Boxshall, Geoffrey Allan; Etyemez, Miray

2013-10-01

263

Unusual ribosomal RNA gene organization in copepods of the genus Calanus.  

PubMed

Ribosomal RNA genes in the nuclear genomes of eukaryotes are generally found in tandemly repeated units encoding 18 S, 5.8 S and 28 S rRNA (in that order). 5 S rRNA genes typically lie outside these units, most often in tandem clusters coding exclusively for 5 S rRNA. Inclusion of 5 S genes within the 18 S-5.8 S-28 S repeat unit is known only for certain protozoa and fungi. Here we report that, in the copepod Calanus finmarchicus, single 5 S genes are included within many or all of the 18 S-5.8 S-28 S repeat units. Sequence analyses of regions cloned from two of these repeat units show that they indeed include 5 S genes (which are distal to 28 S genes) and that these are transcribed from opposite strands. PMID:3681983

Drouin, G; Hofman, J D; Doolittle, W F

1987-08-20

264

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

265

Changes in selection regime cause loss of phenotypic plasticity in planktonic freshwater copepods.  

PubMed

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

266

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

267

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

PubMed

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

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

2013-09-01

268

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

269

Grazing of the copepod Diaptomus connexus on purple sulphur bacteria in a meromictic salt lake.  

PubMed

A meromictic lake ecosystem (Mahoney Lake, BC, Canada) was investigated to elucidate the significance of chemocline bacteria in the total carbon cycle under natural conditions. In this lake, primary production by oxygenic phototrophs was insufficient to support the observed net secondary production of the calanoid copepod Diaptomus connexus and the rotifer Brachionus plicatilis, indicating the presence of additional food sources for consumers. Mahoney Lake harbours the densest population of phototrophic sulphur bacteria ever reported in a natural body of water. This layer is located at the interface between oxic and anoxic water layers and is dominated by the purple sulphur bacterium Amoebobacter purpureus. The transfer rates of A. purpureus carbon to D. connexus determined in stratified mesocosms were very low (0.71 ngC copepod(-1) day(-1)) and accounted for only 0.6% of the observed net biomass increase in the zooplankter. Stable stratification within the mesocosms prevented an upwelling of A. purpureus into the oxic part. However, measurements of carbon fluxes, infrared fluorescence microscopy and stable carbon analysis provided cumulative evidence that, under in situ conditions, the cell carbon of purple sulphur bacteria indeed enters the aerobic food chain via the grazing activity of D. connexus. Based on a two-source isotopic mixing model, A. purpureus represents at least 75-85% of the diet of D. connexus. Autumnal upwelling into oxic water layers and aggregation of A. purpureus cells appear to be the main factors determining the high carbon flux from purple sulphur bacteria to zooplankton under natural conditions, and most probably also play a key role in other aquatic ecosystems. Through this pathway, over 53% of the reduced organic matter of purple sulphur bacteria trapped in anoxic bottom waters is returned to the oxic realm. PMID:11207740

Overmann, J; Hall, K J; Northcote, T G; Beatty, J T

1999-06-01

270

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

PubMed Central

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

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

1998-01-01

271

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

PubMed

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

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

2010-04-01

272

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

273

Fatty alcohols in capelin, herring and mackerel oils and muscle lipids: I. Fatty alcohol details linking dietary copepod fat with certain fish depot fats  

Microsoft Academic Search

It is shown that the shorter chain (C14-C18) minor fatty alcohols in copepods, fish body lipids, and commercial fish oils are all qualitatively present, and quantitatively\\u000a similar in proportions to acids found in the depot fats of capelin and mackerel, and in some herring. Although these fatty\\u000a acids can be formed de novo in fish, copepod alcohols offer an alternative

W. N. Ratnayake; R. G. Ackman

1979-01-01

274

[Effect of the parasitic dinoflagellate Ellobiopsis chattoni (Protozoa: Mastigophora) on the winter mortality of the calanoid copepod Calanus finmarchicus (Crustacea: Copepoda) in the Norwegian Sea].  

PubMed

We studied the effects of the parasitic dinoflagellate Ellobiopsis chattoni on the winter mortality of natural population of the calanoid copepod Calanus finmarchicus in the Norwegian Sea (materials was collected in March-April 1989 and September 1990). Dinoflagellate infection occurred during autumn (the infection rates of copepods with E. chattoni was 15%, as average). Average mortality rate in C. finmarchicus was about 0.08% per day, or about one-tenth of total mortality in winter period. PMID:12070964

Timofeev, S F

2002-01-01

275

Insoluble detoxification of trace metals in a marine copepod Tigriopus brevicornis (Müller) exposed to copper, zinc, nickel, cadmium, silver and mercury  

Microsoft Academic Search

The marine harpacticoid copepods Tigriopus brevicornis were collected along the French Atlantic Coast (Loire Atlantique) and subsequently exposed to different lethal and sublethal\\u000a concentrations of various metals (copper, zinc, nickel, cadmium, silver and mercury) for varying lengths of time. Ultrastructural\\u000a investigations of control and experimentally exposed copepods were performed to investigate the intracellular localization\\u000a of metals using transmission electronic microscopy

Sabria Barka

2007-01-01

276

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

277

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

NASA Astrophysics Data System (ADS)

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

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

1998-06-01

278

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

PubMed

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

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

2014-03-15

279

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

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

280

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

Microsoft Academic Search

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

F. Chen; N. H. Marcus

1997-01-01

281

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

282

Reproducibility of bacterial and copepod density assessment in bathing and artisanal fishing water of the Eastern Mediterranean.  

PubMed

Faecal bacteriological indicators and copepod density assessment are used to predict the environmental health of seawater for recreational bathing and artisanal fishing, respectively. The reproducibility of bacterial culture-count and copepod-microscopic density assessment after respective capturing of the sampled seawater on 0.22 microm Millipore filter and 150 microm mesh sieve copepod net, is determined. The paired t-test was performed to evaluate the reproducibility of each obtained parameter-mean in first and second simultaneous water samplings of a total of 10 sites selected along a 200 km distance, at about 500-1000 m offshore. The means of each bacterial indicator in colony forming units/100 ml of sea water in first versus (vs.) second sampling of the 10 sites, followed by the P values were: total bacterial count (6.3 x 10(2) vs. 6.2 x 10(2), P=0.958), Coliform count (3.9 x 10(2) vs. 2.6 x 10(2), P=0.212), Staphylococcus aureus (3.0 x 10(2) vs. 2.4 x 10(2), P=0.551), and Clostridium perfringens (1.4 x 10 vs. 0.4 x 10, P=0.298). However, the average copepod density in five microscopic fields at magnification of 100x in sample 1 vs. sample 2 were: (1.40 vs. 1.60 respectively, P=0.267). This sampling design along the 200 km coast, the used technique for capturing the indicators, and the quantitative laboratory assessment of the indicator densities resulted in high reproducibility with a non-significant difference between the first and second sampling within the 95% confidence limits (P>0.05), a data in support of future monitoring protocol of the environmental health of the coastal water of the Mediterranean sea. PMID:15369996

Barbour, Elie; Codsi, Renee; Zurayk, Rami

2004-08-01

283

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

Microsoft Academic Search

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 (500–1000m), upper-bathypelagic (1000–2000m), lower-bathypelagic (2000–3000m) and abyssopelagic (3000–5000m) zones of the western subarctic Pacific. Resultant data were grouped into these four sampling zones, four developmental stage\\/sex categories

Tsutomu Ikeda; Atsushi Yamaguchi; Takashi Matsuishi

2006-01-01

284

Diets of calanoid copepods on the West Florida continental shelf: Relationships between food concentration, food composition and feeding activity  

Microsoft Academic Search

Bottle incubations were conducted in March, July\\/August and October 1992. to measure the daily rations (R) and objectively characterize the diets of the calanoid copepodsEucalanus elongatus, Undinula vulgaris, Centropages velificatus andTemora stylifera from the west Florida continental shelf. Daily rations,R, were clustered around two, order-of-magnitude different means, 1.3 and 11.2% of body C d-1, representative of quiescent and active feeding

G. S. Kleppel; C. A. Burkart; K. Carter; C. Tomas

1996-01-01

285

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

286

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

287

Summer egg production rates of paracalanid copepods in subtropical waters adjacent to Australia’s North West Cape  

Microsoft Academic Search

The biological oceanography of waters adjacent to Australia’s North West Cape (21° 49?S, 114° 14?E) was studied during the\\u000a austral summers of 1997\\/98 and 1998\\/99. We measured egg production rate (EPR) by the small paracalanid copepods that dominated\\u000a the calanoid community. Bottle incubation experiments were conducted at a shallow (?20 m) station in the mouth of Exmouth\\u000a Gulf, and at

A. D. McKinnon; S. Duggan

288

An all-conquering ecological journey: from the sea, calanoid copepods mastered brackish, fresh, and athalassic saline waters  

Microsoft Academic Search

Although it is commonly acknowledged that calanoid copepods inhabiting fresh water evolved from marine ancestors via the brackish\\u000a water of estuaries, it is less well appreciated that a restricted number of species with freshwater affinities have conquered\\u000a athalassic saline waters. The global importance of the latter habitat has been under-estimated and, with climate change and\\u000a human population growth, it is

Ian A. E. Bayly; Geoffrey A. Boxshall

2009-01-01

289

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

PubMed

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

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

2014-10-01

290

Overlooked cryptic endemism in copepods: systematics and natural history of the calanoid subgenus Occidodiaptomus Borutzky 1991 (Copepoda, Calanoida, Diaptomidae).  

PubMed

Our comprehension of the phylogeny and diversity of most inland-water crustaceans is currently hampered by their pronounced morphological bradytely, which contributed to the affirmation of the "Cosmopolitanism Paradigm" of freshwater taxa. However, growing evidence of the existence of cryptic diversity and molecular regionalism is available for calanoid copepods, thus stressing the need for careful morphological and molecular studies in order to soundly investigate the systematics, diversity and distribution patterns of the group. Diaptomid copepods were here chosen as model taxa, and the morphological and molecular diversity of the species belonging to the west-Mediterranean diaptomid subgenus Occidodiaptomus were investigated with the aim of comparing the patterns of morphological and molecular evolution in freshwater copepods. Three species currently lumped under the binomen Hemidiaptomus (Occidodiaptomus) ingens and two highly divergent clades within H. (O.) roubaui were distinguished, thus showing an apparent discordance between the molecular distances recorded and Occidodiaptomus morphological homogeneity, and highlighting a noteworthy decoupling between the morphological and molecular diversity in the subgenus. Current Occidodiaptomus diversity pattern is ascribed to a combined effect of ancient vicariance and recent dispersal events. It is stressed that the lack of sound calibration points for the molecular clock makes it difficult to soundly temporally frame the diversification events of interest in the taxon studied, and thus to asses the role of morphological bradytely and of accelerated molecular evolutionary rates in shaping the current diversity of the group. PMID:23026809

Marrone, Federico; Lo Brutto, Sabrina; Hundsdoerfer, Anna K; Arculeo, Marco

2013-01-01

291

Gene conversion yields novel gene combinations in paralogs of GOT1 in the copepod Tigriopus californicus  

PubMed Central

Background Gene conversion of duplicated genes can slow the divergence of paralogous copies over time but can also result in other interesting evolutionary patterns. Islands of genetic divergence that persist in the face of gene conversion can point to gene regions undergoing selection for new functions. Novel combinations of genetic variation that differ greatly from the original sequence can result from the transfer of genetic variation between paralogous genes by rare gene conversion events. Genetically divergent populations of the copepod Tigriopus californicus provide an excellent model to look at the patterns of divergence among paralogs across multiple independent evolutionary lineages. Results In this study the evolution of a set of paralogous genes encoding putative aspartate transaminase proteins (called GOT1 here) are examined in populations of the copepod T. californicus. One pair of duplicated genes, GOT1p1 and GOT1p2, has regions of high divergence between the copies in the face of apparent on-going gene conversion. The GOT1p2 gene also has unique haplotypes in two populations that appear to have resulted from a transfer of genetic variation via inter-paralog gene conversion. A second pair of duplicated genes GOT1Sr and GOT1Sd also shows evidence of gene conversion, but this gene conversion does not appear to have maintained each as a functional copy in all populations. Conclusions The patterns of conservation and sequence divergence across this set of paralogous genes among populations of T. californicus suggest that some interesting evolutionary patterns are occurring at these loci. The results for the GOT1p1/GOT1p2 paralogs illustrate how gene conversion can factor in the creation of a mosaic pattern of regions of high divergence and low divergence. When coupled with rare gene conversion events of divergent regions, this pattern can result in the formation of novel proteins differing substantially from either original protein. The evolutionary patterns across these paralogs show how gene conversion can both constrain and facilitate diversification of genetic sequences. PMID:23845062

2013-01-01

292

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

NASA Astrophysics Data System (ADS)

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

Graeve, Martin; Hagen, Wilhelm; Kattner, Gerhard

1994-05-01

293

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

PubMed

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

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

2013-09-01

294

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

295

Temporal transcription of two antennapedia class homeobox genes in the marine copepod Calanus helgolandicus.  

PubMed

DNA sequence information has been obtained for 2 genes implicated in playing critical roles in copepod development. The first ( Cal-antp) was obtained by screening a Calanus helgolandicus genomic library. It shows homology to Antennapedia homeobox genes from a number of organisms including the centipede (76.8% over 250 bp) and the brine shrimp (75.5% over 220 bp). A second sequence (Hox 12) was obtained through reverse transcription polymerase chain reaction (PCR) of a solid-phase cDNA library constructed from Calanus eggs, and subsequent inverse PCR using a genomic DNA template. The Hox 12 sequence is homologous to the Antennapedia class of genes and shares homology with the chicken HoxB3 gene (71% over 187 bp) and with the fruit fly Sex Combs Reduced ( Scr) homeotic gene (66% identity over 223 bp). Using sequence data from Cal-Antp and Hox 12, specific primers were designed to investigate the temporal expression of these genes by PCR analysis of 10 stage-specific cDNA libraries. PMID:14583812

Lindeque, Penelope K; Smerdon, Gary R

2003-01-01

296

Cryptic speciation on the high seas; global phylogenetics of the copepod family Eucalanidae.  

PubMed Central

Few genetic data are currently available to assess patterns of population differentiation and speciation in planktonic taxa that inhabit the open ocean. A phylogenetic study of the oceanic copepod family Eucalanidae was undertaken to develop a model zooplankton taxon in which speciation events can be confidently identified. A global survey of 20 described species (526 individuals) sampled from 88 locations worldwide found high levels of cryptic diversity at the species level. Mitochondrial (16S rRNA, CO1) and nuclear (ITS2) DNA sequence data support 12 new genetic lineages as highly distinct from other populations with which they are currently considered conspecific. Out of these 12, at least four are new species. The circumglobal, boundary current species Rhincalanus nasutus was found to be a cryptic species complex, with genetic divergence between populations unrelated to geographic distance. 'Conspecific' populations of seven species exhibited varying levels of genetic differentiation between Atlantic and Pacific basins, suggesting that continental landmasses form barriers to dispersal for a subset of circumglobal species. A molecular phylogeny of the family based on both mitochondrial (16S rRNA) and nuclear (ITS2, 18S rRNA) gene loci supports monophyly of the family Eucalanidae, all four eucalanid genera and the 'pileatus' and 'subtenuis' species groups. PMID:14667347

Goetze, Erica

2003-01-01

297

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

298

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

299

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

300

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

PubMed

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

2012-06-01

301

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

PubMed

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

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

2013-02-01

302

Temperature compensation in the escape response of a marine copepod, Calanus finmarchicus (Crustacea).  

PubMed

Calanus finmarchicus, the dominant mesozooplankter of the North Atlantic, is an important food source for many fishes and other planktivores. This species, which has limited diel vertical migration, depends on its fast-start escape response to evade predators. It has myelinated neuronal axons, which contribute to its rapid and powerful escape response. The thermal environment that C. finmarchicus inhabits ranges from below 0 degrees C to 16 degrees C. Previous studies have shown that respiration, growth, and reproductive rates are strongly dependent on temperature, with Q10 > 2.5. A comparable dependence of the escape response could place the animal at higher risk for cold-compensated predators. Our work focused on the temperature dependence of the behavioral response to stimuli that mimic predatory attacks. We found that in contrast to other biological processes, all aspects of the escape response showed a low dependence on temperature, with Q10 values below 2. This low temperature dependence was consistent for escape parameters that involved neural as well as muscle components of the behavioral response. These findings are discussed in the contexts of the predator-prey relations of copepods and the thermal dependence of behavior in other taxa. PMID:16110095

Lenz, P H; Hower, A E; Hartline, D K

2005-08-01

303

Parental exposure to elevated pCO2 influences the reproductive success of copepods  

PubMed Central

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

2014-01-01

304

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

305

Copepod reproductive strategies: life-history theory, phylogenetic pattern and invasion of inland waters  

NASA Astrophysics Data System (ADS)

Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven by tradeoffs that are mediated by the environment in which the organisms live. At the same time, phylogenetic history may circumscribe natural selection by dictating the range of phenotypes upon which selection can act, or by limiting the range of environments encountered. Comparisons of life-history patterns in related organisms provide a powerful tool for understanding both the nature of selection on life-history characters and the diversity of life-history patterns observed in nature. Here, we explore reproductive strategies of the Copepoda, a well defined group with many phylogenetically independent transitions from free-living to parasitic life styles, from marine to inland waters, and from active development to diapause. Most species are iteroparous annuals, and most (with the exception of some parasitic taxa) develop through a relatively restricted range of life-history stages (nauplii and copepodids, or some modification thereof). Within these bounds, we suggest that there may be a causal relationship between the success of numerous copepod taxa in inland waters and the prevalence of either diapause or parasitism within these groups. We hypothesize that inland waters are more variable spatially and temporally than marine habitats, and accordingly, we interpret diapause and parasitism as mechanisms for coping with environmental variance.

Hairston, Nelson G.; Bohonak, Andrew J.

1998-06-01

306

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

307

[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

308

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

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

309

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

310

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

NASA Astrophysics Data System (ADS)

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

Gemmell, Brad; Sheng, Jian; Buskey, Ed

2008-11-01

311

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

312

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

313

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

314

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

315

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 96 h 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 24 h 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 (9 kJ m(-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

316

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

317

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

PubMed

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

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

2012-01-01

318

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

319

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

PubMed Central

Acidification of the seas, caused by increased dissolution of CO2 into surface water, and global warming challenge the adaptation mechanisms of marine organisms. In boreal coastal environments, temperature and pH vary greatly seasonally, but sometimes also rapidly within hours due to upwelling events. We studied if copepod zooplankton living in a fluctuating environment are tolerant to climate change effects predicted for 2100, i.e., a temperature increase of 3°C and a pH decrease of 0.4. Egg production of the copepod Acartia sp. was followed over five consecutive days at four temperature and pH conditions (17°C/ambient pH; 17°C/low pH; 20°C/ambient pH; 20°C/low pH). Egg production was higher in treatments with warmer temperature but the increase was smaller when copepods were simultaneously exposed to warmer temperature and lowered pH. To reveal if maternal effects are important in terms of adaptation to a changing environment, we conducted an egg transplantation experiment, where the produced eggs were moved to a different environment and egg hatching was monitored for three days. When pH changed between the egg production and hatching conditions, it resulted in lower hatching success, but the effect was diminished over the course of the experiment possibly due to improved maternal provisioning. Warmer egg production temperature induced a positive maternal effect and increased the egg hatching rate. Warmer hatching temperature resulted also in earlier hatching. However, the temperature effects appear to be dependent on the ambient sea temperature. Our preliminary results indicate that maternal effects are an important mechanism in the face of environmental change. PMID:23119052

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

2012-01-01

320

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

321

Acute toxicity of cadmium to fish Labeo rohita and copepod Diaptomus forbesi pre-exposed to CaO and KMnO 4  

Microsoft Academic Search

96-h LC50 values of cadmium (Cd) to fish Labeo rohita and the copepod Diaptomus forbesi, determined by static bioassays, were, respectively, 89.5 and 10.2 mg\\/l. LC50 values increased significantly when fish pre-exposed to 100–350 mg\\/l CaO or 0.5–1.5 mg\\/l KMnO4 for 4 d and the copepod to 20–70 mg\\/l CaO or 0.25–1.0 mg\\/l KMnO4 for same period. The LC50 values

Tapas Kumar Dutta; Anilava Kaviraj

2001-01-01

322

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

PubMed

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

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

2010-06-01

323

Characteristics of egg production of the planktonic copepod, Calanus finmarchicus, on Georges Bank: 1994 1999  

NASA Astrophysics Data System (ADS)

We present here a synthesis of observations of egg production rates (EP) of the planktonic copepod, Calanus finmarchicus, carried out during process cruises of the US GLOBEC Northwest Atlantic/Georges Bank program between January and June 1995, 1997 and 1999. Female C. finmarchicus produced eggs at relatively high rates in at least some regions of Georges Bank during all months between January and June. Median, monthly EP varied between 24 eggs female -1 d -1 in January to 50 eggs female -1 d -1 in April-June; the highest mean EP was 86 eggs female -1 d -1. Mean egg diameter was negatively related to ambient mean water-column temperature (0-100 m or bottom), decreasing from 149 to 142 ?m between January and June. Direct measurements of body C or N or prosome length-mass relationships were used to determine mass-specific egg production rates. The relationships between estimates of chlorophyll a standing stock (mg chl. a m -2) and both C- and N-specific rates (% d -1) are reasonably well ( r2=0.42) described by Ivlev curves. It is likely that chlorophyll standing stock serves as a proxy of both phytoplankton and microzooplankton food concentrations available to adult females. Chlorophyll standing stocks were below the critical concentration (at which EP is 95% of the calculated maximum) at approximately 55% of stations occupied over the study period, indicating frequent food limitation to varying extent. There were periods (e.g., over at least 6 d in April, 1997 on the southern flank) during which food limitation was severe. There was no detectable influence of mean water-column temperature on mass-specific EP. Hatching success varied between 50% and 95% without any seasonal trend. Our qualitative observations suggest the possibility that a significant proportion of hatching nauplii incubations were non-viable, meriting further study.

Runge, J. A.; Plourde, S.; Joly, P.; Niehoff, B.; Durbin, E.

2006-11-01

324

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

PubMed

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

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

2012-12-01

325

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

326

Population differentiation in the open sea: insights from the pelagic copepod Pleuromamma xiphias.  

PubMed

Although a number of recent studies of marine holoplankton have reported significant genetic structure among populations, little is currently known about the biological and oceanographic processes that influence population connectivity in oceanic plankton. In order to examine how depth preferences influence dispersal in oceanic plankton, I characterized the genetic structure of a copepod with diel vertical migration (DVM) (Pleuromamma xiphias), throughout its global distribution, and compared these results to those expected given the interaction of this species' habitat depth with ocean circulation and bathymetry. Mitochondrial COI sequences from 651 individuals from 28 sites in the Indian, Pacific, and Atlantic Oceans revealed highly significant genetic differentiation both within and among ocean basins. Limited dispersal among distinct pelagic provinces seems to have played a major role in population differentiation in this species, with strong genetic breaks observed across known oceanographic fronts or current systems in all three ocean basins. The Indo-West Pacific (IWP) holds a highly distinct genetic population of this species that was sampled in both the western Pacific and eastern Indian Oceans. This suggests that the IWP does not act as a strong barrier to gene flow between basins, as expected, despite the relatively shallow water depth (<200 m) and vertically extensive (>400 m) diel migration of this species. A pattern of isolation by distance was observed in the Indian Ocean with genetic differentiation among samples down to spatial scales of ?800 km, indicating that realized dispersal in P. xiphias occurs over much smaller spatial scales than in previously reported oceanic holoplankton. Given its highly regionalized population genetic structure, P. xiphias may have some capacity to adapt to local oceanographic conditions, and it should not be assumed that populations of this species in distinct pelagic biomes will respond in the same way to shared physical or climatic forcing. PMID:21940778

Goetze, Erica

2011-10-01

327

Mating behaviours of Daphnia pulicaria, a cyclic parthenogen: comparisons with copepods  

PubMed Central

The pre-and post-contact mating behaviours of Daphnia pulicaria are investigated by direct observations of vertical distributions, swimming behaviours and male-female interactions. Analysis of vertical distributions in a 1 m deep, thermally stratified migration chamber reveals that females were always located in the upper layer of the water column but males exhibited a bimodal depth distribution, in which an individual's depth was a function of body length and water temperature. The observed distributions of males may be the result of several interacting pressures; predation avoidance, life-history optimization, and avoidance of assortative mating. Male swimming behaviour was faster and orthogonal to that of females, which is in agreement with the predictions of encounter-rate maximization models. Video recordings of males and females interacting in a 1-litre vessel showed that males both pursued and contacted other males more often than females. Thus, there was no evidence that Daphnia are able to use water-borne chemical signals to locate and identify potential mates. However, the average duration of male-female contacts (13.8 s) was much longer than those between males (1.6 s), suggesting that males can determine the sex of contacted individuals.Daphnia mating behaviour is significantly more complex than previously acknowledged. In contrast to the conventional view of Daphnia males swimming more-or-less randomly and mating with any individual encountered, they exhibit behaviours which increase the potential of mating with females while reducing the risk of predation. Several male behaviours, such as 'scanning' and the performance of area-restricted spirals upon encounter, are similar to those reported for some copepods and may be common to zooplankton that lack sophisticated chemosensory abilities. The possibility that Daphnia may also be able to assess such important female attributes as species and reproductive status is discussed.

Brewer, M. C.

1998-01-01

328

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

329

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

330

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

331

Identification and expression of the ecdysone receptor in the harpacticoid copepod, Amphiascus tenuiremis, in response to fipronil.  

PubMed

The marine copepod, Amphiascus tenuiremis (A. tenuiremis), is a well characterized invertebrate model for the screening and evaluation of endocrine and reproductive toxins using life-cycle assays. These tests evaluate phenotypic endpoints related to development and reproduction, which are utilized to predict population outcomes. Some of these endpoints in arthropods, including sexual maturation and molting, are controlled by the hormone ecdysone which acts through its cognate receptor, the ecdysone receptor. The purpose of this research was to obtain and characterize sequence information for the A. tenuiremis ecdysone receptor and investigate modulation of expression levels by fipronil, an insecticide that causes infertility in males and reduced egg extrusion in female copepods, and ponasterone, a natural ecdysone receptor agonist. Results show successful cloning and phylogenetic analysis of the ecdysone receptor for A. tenuiremis, providing the first genetic information for a hormone receptor in this species. Exposure of copepodites to fipronil for 1, 2, 4, 18 and 30 h caused a significant increase in ecdysone receptor transcriptional expression at 30 h compared to control unexposed animals. This work illustrates a potential mechanism whereby exposure to fipronil, and potentially other endocrine disrupting compounds, results in impacted reproduction. Furthermore, this exemplifies the potential utility of ecdysone receptor transcriptional measurement as a sensitive and rapid biomarker of ecological relevance when linked to traditional A. tenuiremis bioassays. PMID:22000904

Gaertner, Karin; Chandler, G Thomas; Quattro, Joseph; Ferguson, P Lee; Sabo-Attwood, Tara

2012-02-01

332

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

333

Suppression subtractive hybridization library prepared from the copepod Calanus finmarchicus exposed to a sublethal mixture of environmental stressors.  

PubMed

A library of expressed sequence tags (ESTs) was constructed by the use of suppression subtractive hybridization polymerase chain reaction (SSH PCR) technique from the marine copepod Calanus finmarchicus. Samples used were from controls (seawater, 10 degrees C) and exposed (sublethal mixture) individuals. The sublethal exposure regime consisted of a mixture of mono ethanol amine (MEA), water-soluble fractions of oil (WSFs), copper (Cu) and elevated temperature (17 degrees C). The resulting 189 unique ESTs consisted of 127 putatively up-regulated genes and 54 putatively down-regulated genes. Annotation analyses revealed altered expression of a wide variety of genes, among these putative heat shock protein 90 (HSP-90), antioxidants (thioredoxin reductase, glutathione peroxidase) and cytochrome P450 enzymes. In addition, sequences showing high similarity to enzymes involved in fatty acid metabolism, energy metabolism and amine handling were found further confirming the effects of the exposure. The annotated sequences are discussed in relation to the present exposure as well as known physiological mechanisms known in C. finmarchicus and related copepod species. The sequenced ESTs from our C. finmarchicus library will provide an excellent tool for future studies on this species, both from a toxicogenomic and systems biology point of view. PMID:20483299

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

2007-09-01

334

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

335

SARGENT, J. R., AND S. FALK-PETERSEN. 1988. The lipid biochem-istry of Calanoid copepods. Hydrobiol. 167/168: 101-114.  

E-print Network

that the equivalent of -60% of the total annual input of Cd, Ni, and Zn from local waste-water treatment plants. O'Hara [eds.], The biological chemistry of marine copepods. Oxford. STOECKER, D. K., AND J. M when the bloom was predicted. Factors that might confound observations of biological influ- ences

van Geen, Alexander

336

Parasitic Copepod (Lernaea cyprinacea) Outbreaks in Foothill Yellow-legged Frogs (Rana boylii) Linked to Unusually Warm Summers and Amphibian Malformations in Northern California  

Microsoft Academic Search

How climate change may affect parasite-host assemblages and emerging infectious diseases is an important question in amphibian decline research. We present data supporting a link between periods of unusually warm summer water temperatures during 2006 and 2008 in a northern California river, outbreaks of the parasitic copepod Lernaea cyprinacea, and malformations in tadpoles and young of the year Foothill Yellow-legged

Sarah J. Kupferberg; Alessandro Catenazzi; Kevin Lunde; Amy J. Lind; Wendy J. Palen

2009-01-01

337

Journal of Plankton Research Vol.19 no.9 pp.1289-1304, 1997 The escape behavior of marine copepods in response to a  

E-print Network

Journal of Plankton Research Vol.19 no.9 pp.1289-1304, 1997 The escape behavior of marine copepods within a single species. In general, animals captured from more energetic regimes required a higher values with 51.5 s~' for 50% of the animals tested to elicit an escape reac- tion (5jo). Acartia tonsa

Yen, Jeannette

338

Acute toxicity of cadmium to fish Labeo rohita and copepod Diaptomus forbesi pre-exposed to CaO and KMnO4.  

PubMed

96-h LC50 values of cadmium (Cd) to fish Labeo rohita and the copepod Diaptomus forbesi, determined by static bioassays, were, respectively, 89.5 and 10.2 mg/l. LC50 values increased significantly when fish pre-exposed to 100-350 mg/l CaO or 0.5-1.5 mg/l KMnO4 for 4 d and the copepod to 20-70 mg/l CaO or 0.25-1.0 mg/l KMnO4 for same period. The LC50 values also increased when the pre-exposure period of CaO was increased to 12 d at concentration 100 mg/l for fish and 20 mg/l for copepod. All fish died when pre-exposed to 1.5 mg/l KMnO4 for 8 d. But LC50 values of Cd to copepod increased when pre-exposure period of 0.5 mg/l KMnO4 was increased from 4 to 8 d. PMID:11272918

Dutta, T K; Kaviraj, A

2001-03-01

339

Responses of the chaetognath, Sagitta elegans, and larval Pacific hake, Merluccius productus, to spring diatom and copepod blooms in a temperate fjord (Dabob Bay, Washington)  

NASA Astrophysics Data System (ADS)

As part of a broader field study examining the potentially deleterious effects of diatoms on planktonic food webs, we examined the abundance, stage composition, diet, and feeding success of the chaetognath, Sagitta elegans, and the abundance and morphometric condition of larval Pacific hake, Merluccius productus. Our objective was to look for a relationship between spring phytoplankton blooms and planktonic predators, as mediated by their copepod prey, with special reference to possible deleterious effects of diatoms. Zooplankton were collected weekly during February-May and in mid-summer of 2002 and 2003 in Dabob Bay, Washington State, USA. S. elegans abundance was high in summer of both years and was higher in spring 2003 than spring 2002. Larval chaetognaths dominated the population in early spring and remained present throughout sampling. S. elegans consumed mostly copepods. The abundance of larval S. elegans was correlated with the abundance of copepodites, although no relationship between chaetognath feeding success and prey abundance was found. Larval Pacific hake abundance was high (1200 larvae per square meter) in late February and early March of 2002 and 2003 and decreased rapidly in late spring. The morphometric condition of M. productus was not significantly related to copepod abundance. These results indicate that any deleterious effects of diatoms on copepod abundance, at the scale seen during spring 2002 and 2003 in Dabob Bay, did not greatly affect the next higher trophic level.

Fulmer, Julia H.; Bollens, Stephen M.

2005-11-01

340

Downward carbon transport by diel vertical migration of the copepods Metridia pacifica and Metridia okhotensis in the Oyashio region of the western subarctic Pacific Ocean  

Microsoft Academic Search

Seasonal change in the downward carbon transport due to respiration and mortality through diel vertical migration (DVM) of the calanoid copepods Metridia pacifica and Metridia okhotensis was estimated in the Oyashio region, western subarctic Pacific during six cruises from June 2001 to June 2002. M. pacifica (C4, C5 and adult females) was an active migratory species throughout the year though

Kazutaka Takahashi; Akira Kuwata; Hiroya Sugisaki; Kazuhisa Uchikawa; Hiroaki Saito

2009-01-01

341

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

342

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

343

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

344

A study of zooplankton in the Corpus Christi ship channel area near Ingleside, Texas  

E-print Network

tonsa. Oithona spp. Copepod nauplii. Ophiopluteus larvae. O~kl p. 54 61 66 66 69 69 TABLE OF CONTENTS Page Barnacle nauplii. Paracalanus crassirostris. Gastropod larvae. Polychaete larvae. Pseudodiaptomus coronatus Bivalve larvae Fish... to the estuarine zoo- plankton assemblage. The larval stages of fish, shrimp, crabs and oysters belong to the meroplankton as to polychaete and barnacle larvae, whereas Copepods, Cladocerans, Larvaceans, Chaetognaths and Ctenophores belong to the holoplankton...

Ansari, Fahmida

1979-01-01

345

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

NASA Astrophysics Data System (ADS)

Calanus spp. copepods play a key role in the Arctic pelagic ecosystem. Among four congeneric species of Calanus found in the Arctic Ocean and its marginal seas, two are expatriates in the Arctic (Calanus finmarchicus and Calanus marshallae) and two are endemic (Calanus glacialis and Calanus hyperboreus). The biogeography of these species likely is controlled by the interactions of their life history traits and physical environment. A mechanistic understanding of these interactions is critical to predicting their future responses to a warming environment. Using a 3-D individual-based model that incorporates temperature-dependent and, for some cases, food-dependent development rates, we show that (1) C. finmarchicus and C. marshallae are unable to penetrate, survive, and colonize the Arctic Ocean under present conditions of temperature, food availability, and length of the growth season, mainly due to insufficient time to reach their diapausing stage and slow transport of the copepods into the Arctic Ocean during the growing season or even during the following winter at the depths the copepods are believed to diapause. (2) For the two endemic species, the model suggests that their capability of diapausing at earlier copepodite stages and utilizing ice-algae as a food source (thus prolonging the growth season length) contribute to the population sustainability in the Arctic Ocean. (3) The inability of C. hyperboreus to attain their first diapause stage in the central Arctic, as demonstrated by the model, suggests that the central Arctic population may be advected from the surrounding shelf regions along with multi-year successive development and diapausing, and/or our current estimation of the growth parameters and the growth season length (based on empirical assessment or literature) needs to be further evaluated. Increasing the length of the growth season or increasing water temperature by 2 °C, and therefore increasing development rates, greatly increased the area of the central Arctic in which the Arctic endemics could reach diapause but had little effect on the regions of successful diapause for the expatriate species.

Ji, Rubao; Ashjian, Carin J.; Campbell, Robert G.; Chen, Changsheng; Gao, Guoping; Davis, Cabell S.; Cowles, Geoffrey W.; Beardsley, Robert C.

2012-04-01

346

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

347

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

348

Molecular and functional analysis of three fatty acyl-CoA reductases with distinct substrate specificities in copepod Calanus finmarchicus.  

PubMed

The marine copepod Calanus finmarchicus constitutes the substantial amount of biomass in the Arctic and Northern seas. It is unique in that this small crustacean accumulates a high level of wax esters as carbon storage which is mainly comprised of 20:1n-9 and 22:1n-11 alcohols (Alc) linked with various kinds of fatty acids, including n-3 polyunsaturated fatty acids. The absence of 20:1n-9 Alc and 22:1n-11 Alc in diatoms and dinoflagellates, the primary food sources of copepods, suggests the existence of de novo biosynthesis of fatty alcohols in C. finmarchinus. Here, we report identification of three genes, CfFAR1, CfFAR2, and CfFAR3, coding for fatty acyl-CoA reductases involved in the conversion of various fatty acyl-CoAs to their corresponding alcohols. Functional characterization of these genes in yeast indicated that CfFAR1 could use a wide range of saturated fatty acids from C18 to C26 as substrates, CfFAR2 had a narrow range of substrates with only very-long-chain saturated fatty acid 24:0 and 26:0, while CfFAR3 was active towards both saturated (16:0 and 18:0) and unsaturated (18:1 and 20:1) fatty acids producing corresponding alcohols. This finding suggested that these three fatty acyl-CoA reductases are likely responsible for de novo synthesis of a series of fatty alcohol moieties of wax esters in C. finmarchicus. PMID:21918929

Teerawanichpan, Prapapan; Qiu, Xiao

2012-04-01

349

Comparison of molecular species identification for North Sea calanoid copepods (Crustacea) using proteome fingerprints and DNA sequences.  

PubMed

Calanoid copepods play an important role in the pelagic ecosystem making them subject to various taxonomic and ecological studies, as well as indicators for detecting changes in the marine habitat. For all these investigations, valid identification, mainly of sibling and cryptic species as well as early life history stages, represents a central issue. In this study, we compare species identification methods for pelagic calanoid copepod species from the North Sea and adjacent regions in a total of 333 specimens. Morphologically identified specimens were analysed on the basis of nucleotide sequences (i.e. partial mitochondrial cytochrome c oxidase subunit I (COI) and complete 18S rDNA) and on proteome fingerprints using the technology of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). On all three molecular approaches, all specimens were classified to species level indicated by low intraspecific and high interspecific variability. Sequence divergences in both markers revealed a second Pseudocalanus species for the southern North Sea identified as Pseudocalanus moultoni by COI sequence comparisons to GenBank. Proteome fingerprints were valid for species clusters irrespective of high intraspecific variability, including significant differences between early developmental stages and adults. There was no effect of sampling region or time; thus, trophic effect, when analysing the whole organisms, was observed in species-specific protein mass spectra, underlining the power of this tool in the application on metazoan species identification. Because of less sample preparation steps, we recommend proteomic fingerprinting using the MALDI-TOF MS as an alternative or supplementary approach for rapid, cost-effective species identification. PMID:23848968

Laakmann, S; Gerdts, G; Erler, R; Knebelsberger, T; Martínez Arbizu, P; Raupach, M J

2013-09-01

350

Feeding, egg production, and egg hatching success of the copepods Acartia tonsa and Temora longicornis on diets of the toxic diatom Pseudo-nitzschia multiseries and the non-toxic diatom Pseudo-nitzschia pungens  

Microsoft Academic Search

In 1987, there was an episode of shellfish poisoning in Canada with human fatalities caused by the diatom Pseudonitzschia multiseries, which produced the toxin domoic acid. In order to examine whether domoic acid in this diatom serves as a grazing deterrent\\u000a for copepods, we compared feeding rates, egg production rates, egg hatching success and mortality of the calanoid copepods\\u000a Acartia

Jean A. Lincoln; Jefferson T. Turner; Stephen S. Bates; Claude Léger; David A. Gauthier

2001-01-01

351

Patterns in the distribution of Arctic freshwater zooplankton related to glaciation history  

Microsoft Academic Search

We analysed circumpolar samples from 68 lakes within the 10°C-July isotherm from Arctic Canada, Nunavut, Greenland, Svalbard,\\u000a Eastern Siberia, the Beringia region, and Alaska. In total, we found 3 species of Anostraca, 17 of Diplostraca, 1 species\\u000a of cyclopoid and 14 species of calanoid copepods. Our study identifies a wider distribution for some copepods—e.g. Eurytemora\\u000a pacifica, Leptodiaptomus sicilis, Arctodiaptomus novosibiricus,

Larysa Samchyshyna; Lars-Anders Hansson; Kirsten Christoffersen

2008-01-01

352

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

353

Fish-flamingo-plankton interactions in the Peruvian Andes  

Microsoft Academic Search

The zooplankton and flamingo populations of 20 high elevation (3,700-4,700 m) lakes in the Andes of southern Peru were assessed on one to three occasions each. Some of these lakes have cyprinodont fish (Orestias spp.), others do not. Lakes with fish usually have a sparse zooplankton dominated by cyclopoid copepods and chydorid cladocerans; the others tend to have an abundant

STUART H. HURLBERT; WASHINGTON LOAYZA; TOMAS MORENO

1986-01-01

354

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

355

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

356

The effects of temperature and oxygen partial pressure on the rate of oxygen consumption of the high-shore rock pool copepod Tigriopus brevicornis  

Microsoft Academic Search

Inhabitants of littoral rock pools such as the copepod Tigriopus brevicornis are subjected to highly variable physico-chemical conditions. The effect of temperature and PO2 on the rate of oxygen consumption of T. brevicornis from a Scottish population was studied. As expected, VO2 increased with increasing temperature over the range 5–30°C. However, at 0 and 35°C the rates of oxygen consumption

Rob McAllen; Alan C. Taylor; John Davenport

1999-01-01

357

Diel variations of copepod feeding and grazing impact in the high-nutrient, low-chlorophyll zone of the equatorial Pacific Ocean (0°; 3°S, 180°)  

Microsoft Academic Search

Diel variations of copepod biomass and feeding were studied at two time series stations in the high-nutrient, low-chlorophyll region of the central equatorial Pacific (0° and 3°S, 180°). During 48-hour studies at each station, samples were taken at 3-hour frequency in the neuston layer (0–1 m) and over the 0–100 m depth range. Feeding rates were assessed through the spectrofluorometric

Gisèle Champalbert; Jacques Neveux; Raymond Gaudy; Robert Le Borgne

2003-01-01

358

Diel variations of copepod feeding and grazing impact in the high-nutrient, low-chlorophyll zone of the equatorial Pacific Ocean (0° 3°S, 180°)  

Microsoft Academic Search

Diel variations of copepod biomass and feeding were studied at two time series stations in the high-nutrient, low-chlorophyll region of the central equatorial Pacific (0° and 3°S, 180°). During 48-hour studies at each station, samples were taken at 3-hour frequency in the neuston layer (0-1 m) and over the 0-100 m depth range. Feeding rates were assessed through the spectrofluorometric

Gisèle Champalbert; Jacques Neveux; Raymond Gaudy; Robert Le Borgne

2003-01-01

359

Effects of temperature and nutritional state on the toxicity of acridine to the calanoid copepod, Diaptomus clavipes Schacht. [Diaptomus claripes, Daphnia magna  

SciTech Connect

Acute and chronic bioassays were performed on the calanoid copepod, Diaptomus clavipes, using the azaarene, acridine, as the test compound. Tests were performed at three temperatures (16/sup 0/, 21/sup 0/, 26/sup 0/C) and over a range of nutritional conditions. Survival, growth, development, and reproduction were all affected by exposure to acridine. These effects were modified by temperature and nutritional state of the animals.

Cooney, J.D.; Gehrs, C.W.; Bunting, D.L. II

1983-07-01

360

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

361

First record of association of copepods with highly venomous box jellyfish chironex, with description of new species of paramacrochiron (cyclopoida: macrochironidae).  

PubMed

Paramacrochiron chironecicola n. sp. (Copepoda: Cyclopoida: Macrochironidae) is described from the highly venomous box jellyfish Chironex sp. collected from Malampaya Sound, Palawan Island, The Philippines. This is the first record of copepods associated with cubozoan medusae, although other cnidarian groups such scyphozoans, hydrozoans, and anthozoans are common hosts for symbiotic copepods. The infection sites were on the subumbrella, pedalium, and rhopalium, but also rarely on the adradial furrow. The new species is distinguished from other congeners by a combination of the following features: (1) the fifth pedigerous somite dorsally covering the anterior part of the female genital double-somite; (2) the fine structures of the antenna (relative lengths of segments) and maxilliped (positions of terminal elements) of the female; (3) the relatively long outer spines on the exopodal segments of legs 1-4; (4) the relatively long and thick female leg 5 bearing a long protopodal seta which reaches to the distal margin of the exopod; (5) the relatively short caudal ramus in the female; and (6) the plump prosome and short urosome in the male. Since members of the genus typically parasitize scyphozoans, especially rhizostomes, the association of this parasitic copepod on cubozoans may reflect the relatively close phylogenetic relationship between cubozoans and scyphozoans. PMID:25826070

Ohtsuka, Susumu; Metillo, Ephrime; Boxshall, Geoffrey A

2015-04-01

362

Fatty acid utilisation and metabolism in caecal enterocytes of rainbow trout (Oncorhynchus mykiss) fed dietary fish or copepod oil.  

PubMed

A combined fatty acid metabolism assay was employed to determine fatty acid uptake and relative utilisation in enterocytes isolated from the pyloric caeca of rainbow trout. In addition, the effect of a diet high in long-chain monoenoic fatty alcohols present as wax esters in oil derived from Calanus finmarchicus, compared to a standard fish oil diet, on caecal enterocyte fatty acid metabolism was investigated. The diets were fed for 8 weeks before caecal enterocytes from each dietary group were isolated and incubated with [1-14C]fatty acids: 16:0, 18:1n-9, 18:2n-6, 18:3n-3, 20:1n-9, 20:4n-6, 20:5n-3, and 22:6n-3. Uptake was measured over 2 h with relative utilisation of different [1-14C]fatty acids calculated as a percentage of uptake. Differences in uptake were observed, with 18:1n-9 and 18:2n-6 showing the highest rates. Esterification into cellular lipids was highest with 16:0 and C18 fatty acids, accounting for over one-third of total uptake, through predominant incorporation in triacylglycerol (TAG). The overall utilisation of fatty acids in phospholipid synthesis was low, but highest with 16:0, the most prevalent fatty acid recovered in intracellular phosphatidylcholine (PC) and phosphatidylinositol (PI), although exported PC exhibited higher proportions of C20/C22 polyunsaturated fatty acids (PUFA). Other than 16:0, incorporation into PC and PI was highest with C20/C22 PUFA and 20:4n-6 respectively. Recovery of labelled 18:1n-9 in exported TAG was 3-fold greater than any other fatty acid which could be due to multiple esterification on the glycerol 'backbone' and/or increased export. Approximately 20-40% of fatty acids taken up were beta-oxidised, and was highest with 20:4n-6. Oxidation of 20:5n-3 and 22:6n-3 was also surprisingly high, although 22:6n-3 oxidation was mainly attributed to retroconversion to 20:5n-3. Metabolic modification of fatty acids by elongation-desaturation was generally low at <10% of [1-14C]fatty acid uptake. Dietary copepod oil had generally little effect on fatty acid metabolism in enterocytes, although it stimulated the elongation and desaturation of 16:0 and elongation of 18:1n-9, with radioactivity recovered in longer n-9 monoenes. The monoenoic fatty acid, 20:1n-9, abundant in copepod oil as the homologous alcohol, was poorly utilised with 80% of uptake remaining unesterified in the enterocyte. However, the fatty acid composition of pyloric caeca was not influenced by dietary copepod oil. PMID:16257262

Oxley, Anthony; Tocher, Douglas R; Torstensen, Bente E; Olsen, Rolf E

2005-12-15

363

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

364

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

365

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

NASA Astrophysics Data System (ADS)

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

Cass, Christine J.; Daly, Kendra L.

2014-12-01

366

Toxicity of estuarine sediments using a full life-cycle bioassay with the marine copepod Robertsonia propinqua.  

PubMed

Estuarine sediment contamination is a growing significant ecological issue in New Zealand. Methods of assessing toxicity and ecological impacts in a cost effective way are currently limited. Further to that is a need to develop bioassays that generate data quickly and cost effectively and have ecological relevance to the wider community. A chronic full life-cycle bioassay to assess the toxicity of New Zealand estuarine sediments using the marine harpacticoid copepod Robertsonia propinqua has been investigated. Sediment samples were collected from the Bay of Plenty region and included two polluted and one reference site. Sources of pollutants in the contaminated field sites originated from a variety of sources and generally include nutrients, pesticides and herbicides and the pollutants zinc, copper, lead and polycyclic aromatic hydrocarbons (PAHs). Conversely, the reference site was exposed to low levels of contaminants due to the relatively undeveloped catchment. Adult male and female copepods were exposed to field collected sediments for 24 days under flow-through conditions at 21 degrees C and 12h L:D cycles. Five endpoints were recorded: male and female survival, fecundity (number of gravid females per replicate at the end of the test), clutch size per female, number of eggs per sample and juvenile survival (number of nauplii and copepodites per replicate at the end of the test). Adult mortality was observed in all sediment samples but the number of males, gravid females, clutch size per female and number of eggs produced were not affected by either the contaminated or reference sediment samples. However, the contaminated sediments did reduce reproductive output (i.e. nauplii and copepodite production). Therefore, we conclude that reproductive endpoints provide a good measure of sediment-associated contaminant effects compared with adult R. propinqua survivorship. It may be that a change in focus from chemical thresholds without ecological relevance or lethal dose threshold methods, to more subtle but ecologically significant elements of faunal life, such as reproductive success, are a more sensitive and a long term ecologically informative method. PMID:18242700

Hack, Lisa A; Tremblay, Louis A; Wratten, Steve D; Forrester, Guy; Keesing, Vaughan

2008-07-01

367

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

368

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

369

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

PubMed

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

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

2014-11-01

370

Unusually high numbers of ribosomal RNA genes in copepods (Arthropoda: Crustacea) and their relationship to genome size.  

PubMed

We report on copy numbers of 18S ribosomal RNA genes in three species of copepods (Crustacea: Copepoda), two of which possess an unusual arrangement in which 5S genes are included within the 18S-5.8S-28S repeat unit. Slot blots of genomic and standard DNA were hybridized with an 18S rRNA gene probe constructed from one of the marine species and hybridization was quantified using chemiluminescence. Diploid 18S rRNA gene copy numbers are estimated as ca. 15 300 and 33 500 in the marine species Calanus finmarchicus (13.0 pg DNA in 2C adult nuclei) and C. glacialis (24.2 pg DNA), respectively, and ca. 840 and 730 in two freshwater populations of Mesocyclops edax (both ca. 3 pg DNA) from Virginia and Nova Scotia, respectively. The roughly proportional relationship between 2C somatic nuclear DNA contents and rRNA gene copy number in the sibling species C. finmarchicus and C. glacialis may reflect polytenic replication of entire genomes during abrupt speciation events. Copy numbers may also reflect differential losses during embryonic chromatin diminution. PMID:18470156

Wyngaard, G A; McLaren, I A; White, M M; Sévigny, J M

1995-02-01

371

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

PubMed

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

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

2014-01-01

372

Immunohistochemical mapping of histamine, dopamine, and serotonin in the central nervous system of the copepod Calanus finmarchicus (Crustacea; Maxillopoda; Copepoda).  

PubMed

Calanoid copepods constitute an important group of marine planktonic crustaceans that often dominate the metazoan biomass of the world's oceans. In proportion to their ecological importance, little is known about their nervous systems. We have used immunohistochemical techniques in a common North Atlantic calanoid to localize re-identifiable neurons that putatively contain the biogenic amines histamine, dopamine, and serotonin. We have found low numbers of such cells and cell groups (approximately 37 histamine pairs, 22 dopamine pairs, and 12 serotonin pairs) compared with those in previously described crustaceans. These cells are concentrated in the anterior part of the central nervous system, the majority for each amine being located in the three neuromeres that constitute the brain (protocerebrum, deutocerebrum, and tritocerebrum). Extensive histamine labeling occurs in several small compact protocerebral neuropils, three pairs of larger, more posterior, paired, dense neuropils, and one paired diffuse tritocerebral neuropil. The most concentrated neuropil showing dopamine labeling lies in the putative deutocerebrum, associated with heavily labeled commissural connections between the two sides of the brain. The most prominent serotonin neuropil is present in the anterior medial part of the brain. Tracts of immunoreactive fibers of all three amines are prominent in the cephalic region of the nervous system, but some projections into the most posterior thoracic regions have also been noted. PMID:20532915

Hartline, Daniel K; Christie, Andrew E

2010-07-01

373

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

374

High dispersal potential has maintained long-term population stability in the North Atlantic copepod Calanus finmarchicus.  

PubMed

The cool-water copepod Calanus finmarchicus is a key species in North Atlantic marine ecosystems since it represents an important food resource for the developmental stages of several fish of major economic value. Over the last 40 years, however, data from the Continuous Plankton Recorder survey have highlighted a 70 per cent reduction in C. finmarchicus biomass, coupled with a gradual northward shift in the species's distribution, which have both been linked with climate change. To determine the potential for C. finmarchicus to track changes in habitat availability and maintain stable effective population sizes, we have assessed levels of gene flow and dispersal in current populations, as well as using a coalescent approach together with palaeodistribution modelling to elucidate the historical population demography of the species over previous changes in Earth's climate. Our findings indicate high levels of dispersal and a constant effective population size over the period 359,000-566,000 BP and suggest that C. finmarchicus possesses the capacity to track changes in available habitat, a feature that may be of crucial importance to the species's ability to cope with the current period of global climate change. PMID:18812293

Provan, Jim; Beatty, Gemma E; Keating, Sianan L; Maggs, Christine A; Savidge, Graham

2009-01-22

375

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

376

High dispersal potential has maintained long-term population stability in the North Atlantic copepod Calanus finmarchicus  

PubMed Central

The cool-water copepod Calanus finmarchicus is a key species in North Atlantic marine ecosystems since it represents an important food resource for the developmental stages of several fish of major economic value. Over the last 40 years, however, data from the Continuous Plankton Recorder survey have highlighted a 70 per cent reduction in C. finmarchicus biomass, coupled with a gradual northward shift in the species's distribution, which have both been linked with climate change. To determine the potential for C. finmarchicus to track changes in habitat availability and maintain stable effective population sizes, we have assessed levels of gene flow and dispersal in current populations, as well as using a coalescent approach together with palaeodistribution modelling to elucidate the historical population demography of the species over previous changes in Earth's climate. Our findings indicate high levels of dispersal and a constant effective population size over the period 359?000–566?000?BP and suggest that C. finmarchicus possesses the capacity to track changes in available habitat, a feature that may be of crucial importance to the species's ability to cope with the current period of global climate change. PMID:18812293

Provan, Jim; Beatty, Gemma E.; Keating, Sianan L.; Maggs, Christine A.; Savidge, Graham

2008-01-01

377

? 1999, by the American Society of Limnology and Oceanography, Inc. First evidence of some dinoflagellates reducing male copepod fertilization capacity  

E-print Network

Evidence is presented that hatching failure in Temora stylifera eggs can depend on poor sperm quality. Three dinoflagellate diets, Prorocentrum micans, Gymnodinium sanguinium, and Gonyaulax polyedra, significantly modified spermatophore production and reduced the fertilization capacity of male sperm after 6–12 d of continuous feeding. Two other diets, the dinoflagellate P. minimum and the prymnesiophycean Isochrysis galbana, had no effect on hatching success, which remained high (?89%) and stable with time. A reduction in fertilization capacity was neither due to maternal effects nor to male age since hatching success returned to normal upon the introduction of freshly caught wild males or males conditioned with a good diet such as P. minimum for the same length of time as couples fed with the poor diets, P. micans, G. sanguinium, and G. polyedra. Confocal microscope images of unhatched eggs colored with a nucleus-specific fluorescent dye confirmed that these eggs had not been fertilized. Experiments with Calanus helgolandicus females, which did not require reinsemination and which were fed the same diets that induced hatching failure in T. stylifera, showed no change in hatching success with time. Copepod fecundity has been shown to be strongly related to food type, with some foods that are better than others for promoting higher egg production. High production has been

A. Ianora; A. Miralto; I. Buttino; G. Romano; S. A. Poulet

378

Effects of temperature and nutritional state on the acute toxicity of acridine to the calanoid copepod, Diaptomus clavipes Schacht  

SciTech Connect

Acute toxicity tests were performed on adult males and females of a freshwater calanoid copepod, Diaptomus clavipes Schacht, using the azaarene acridine as the test compound. Tests were performed at three temperatures (16, 21 and 26/sup 0/C) and over a range of nutritional states (fed, starved and stock). Observations on mortality were made at 24-h intervals for 96 h. Analysis of the data was based on comparisons (using different treatment combinations) of the parameters in a logistic survival function used to describe the mortality data. Median lethal concentrations (using 96-h LC/sub 50/ values) were estimated from the logistic survival function as well as from the probit function, for comparative purposes. The LC/sub 50/ values ranged from 1.64 to 6.70 mg/L, depending on temperature, nutritional state of the animals and sex. The LC/sub 50/ values were highest for animals (fed before testing) at 16/sup 0/C. As food availability decreased and temperature increased, toxicity of acridine increased up to fourfold. No significant differences in LC/sub 50/ values were found between the sexes except in starved animals at 26/sup 0/C, when males were more sensitive than females. This difference in toxicity between the sexes at 26/sup 0/C may be due to differences in nutritional stress between the sexes (at this temperature), since control mortality at this temperature was also higher in males than in females.

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

1983-01-01

379

Cytochrome oxidase I sequences reveal possible cryptic diversity in the cosmopolitan symbiotic copepod Nesippus orientalis Heller, 1868 (Pandaridae: Siphonostomatoida) on elasmobranch hosts from the KwaZulu-Natal coast of South Africa.  

PubMed

Over the past decade, numerous molecular phylogenetic studies uncovered cryptic diversity within the Copepoda, yet very few investigations focused on symbiotic copepods. Here we report mitochondrial DNA cytochrome oxidase I diversity in the cosmopolitan elasmobranch symbiont Nesippus orientalis off the KwaZulu-Natal coast of South Africa. Analysis of partial COI sequences of copepods sampled from a diversity of shark hosts, revealed the presence of two divergent clades. Diversity within the clades does not appear to be structured based on host species, host individual, geographic locality or time of sampling. However, divergence between the two clades seems to be related to host species. Phylogenetic analyses of representatives from the two clades, along with Nesippus spp., Caligus spp. and Lepeophtheirus spp. outgroups, further supports the distinction between the two clades. Future molecular phylogenetic investigations of widespread copepod symbionts most likely will reveal far greater levels of biodiversity than currently recognized. PMID:19723521

Dippenaar, Susan M; Mathibela, Rosaline B; Bloomer, Paulette

2010-05-01

380

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

381

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

PubMed Central

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

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

2014-01-01

382

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

PubMed

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

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

2014-01-01

383

Acidophilic granulocytes in the gills of gilthead seabream Sparus aurata: evidence for their responses to a natural infection by a copepod ectoparasite.  

PubMed

Immunohistochemical and ultrastructural studies were conducted on the gills of gilthead seabream, Sparus aurata L., naturally infected with the copepod ectoparasite Ergasilus lizae (Krøyer, 1863) in order to assess pathology and the host immune cell response. Gills of 56 gilthead seabream were screened for ectoparasites; 36 specimens (64.3%) harbored E. lizae. Intensity of infection was 32.7 ± 8.7 (mean ± SE). Pathological alterations to the gills of the host were more pronounced in close proximity to the copepod site of attachment. The parasite attached to the gills by means of its modified second antennae, occluded the arteries, provoked epithelial hyperplasia and hemorrhages and most often caused lamellar disruption. Numerous granular cells were encountered near the site of E. lizae attachment. In both infected and uninfected gills, the granular cells lay within the filaments and frequently occurred within the connective tissue inside and outside the blood vessels of the filaments. The type of granular cell was identified by immunohistochemical staining by using the monoclonal antibody G7 (mAb G7), which specifically recognizes acidophilic granulocytes (AGs) of S. aurata and with an anti-histamine antibody (as a marker for mast cells, MCs) on sections from 13 uninfected gills and 21 parasitized gills. The use of mAb G7 revealed that, in gills harboring copepods, the number of G7-positive cells (i.e., AGs; 32.9 ± 3.9, mean number of cells per 45,000 ?m2 ± SE) was significantly higher than the density of the same cells in uninfected gills (15.3 ± 3.8; ANOVA, P < 0.05). Few histamine-positive granular cells (i.e., MCs) were found in the uninfected and parasitized gills. Here, we show, for the first time in S. aurata infected gills, that AGs rather than MCs are recruited and involved in the response to E. lizae infection in seabream. PMID:23644766

Lui, Alice; Manera, Maurizio; Giari, Luisa; Mulero, Victoriano; Dezfuli, Bahram Sayyaf

2013-09-01

384

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

385

Genomic characterization and phylogenetic position of two new species in Rhabdoviridae infecting the parasitic copepod, salmon louse (Lepeophtheirus salmonis).  

PubMed

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

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

2014-01-01

386

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

387

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

388

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

389

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

390

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

PubMed

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

2014-01-01

391

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

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

392

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

393

Assessing the in situ fertilization status of two marine copepod species, Temora longicornis and Eurytemora herdmani; how common are unfertilized eggs in nature?  

PubMed

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

394

Suitability of the copepod, Acartia clausi as a live feed for Seabass larvae ( Lates calcarifer Bloch): Compared to traditional live-food organisms with special emphasis on the nutritional value  

Microsoft Academic Search

Though artificial propagation of Asian seabass Lates calcarifer (Bloch) in captivity through induced breeding techniques is standardized under Indian conditions, larval and nursery rearing techniques including suitable nursery feeds have to be standardized to obtain better survival and growth. Feeding experiments in triplicate were conducted to evaluate the suitability of the marine copepod Acartia clausi as live prey for fourteen

M. Rajkumar; K. P. Kumaraguru vasagam

2006-01-01

395

The fate of lipids during development and cold-storage of eggs in the laboratory-reared calanoid copepod, Acartia tonsa Dana, and in response to different algal diets  

Microsoft Academic Search

The calanoid copepod Acartia tonsa was sampled throughout one generation to examine the fate of lipids during development in culture. Effects of dietary input were examined by feeding A. tonsa for at least one generation with specific monoalgal cultures. Four different algae were tested: the cryptophyte Rhodomonas baltica, the haptophyte Isochrysis galbana clone T-iso, the diatom Thalassiosiraweissflogii and the dinoflagellate

J. G Støttrup; J. G Bell; J. R Sargent

1999-01-01

396

Transcriptional profiles of Rel/NF-?B, inhibitor of NF-?B (I?B), and lipopolysaccharide-induced TNF-? factor (LITAF) in the lipopolysaccharide (LPS) and two Vibrio sp.-exposed intertidal copepod, Tigriopus japonicus.  

PubMed

The immune system and the role of immunity-related genes have rarely been studied in copepods, even though copepods have a primitive immune response system and also have a potential in pathogen transport higher trophic levels. In this study, we firstly cloned and characterized three core immune genes such as nuclear factor ?B (NF-?B), inhibitor of NF-?B (I?B), and lipopolysaccharide-induced TNF-? factor (LITAF) genes in the intertidal copepod Tigriopus japonicus. Several in silico analyses based on conserved domains, motifs, and phylogenetic relationships were supporting their annotations. To investigate the immune-related role of three genes, we exposed lipopolysaccharide (LPS) and two Vibrio sp. to T. japonicus. After exposure of different concentrations of LPS and two Vibrio sp., transcripts of TJ-I?B and TJ-LITAF genes were significantly elevated during the time course in a dose-dependent manner, while TJ-NF-?B transcripts were not significantly changed during exposure. These findings demonstrated that the copepod T. japonicus has a conserved immunity against infection. PMID:24096153

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

2014-02-01

397

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.

398

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

NASA Astrophysics Data System (ADS)

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

Unal, Ebru; Bucklin, Ann

2010-10-01

399

Diel variations of copepod feeding and grazing impact in the high-nutrient, low-chlorophyll zone of the equatorial Pacific Ocean (0°; 3°S, 180°)  

NASA Astrophysics Data System (ADS)

Diel variations of copepod biomass and feeding were studied at two time series stations in the high-nutrient, low-chlorophyll region of the central equatorial Pacific (0° and 3°S, 180°). During 48-hour studies at each station, samples were taken at 3-hour frequency in the neuston layer (0-1 m) and over the 0-100 m depth range. Feeding rates were assessed through the spectrofluorometric analysis of gut pigment contents. During the cycles, significant variations of biomass and gut pigment contents were found in both the neuston layer and the 0-100 depth strata. However, the amplitude of day-night variations of feeding was larger and more clearly related to the day-night cycle in the neuston layer than in the water column. Maxima in biomass and gut pigment contents did not coincide in either the surface or the water column. The differences in the mean copepod feeding activities at the equator and at 3°S were related to the mean standing stocks of chl a and to the pattern of undegraded pigments, which were different at the surface and in the water column, especially at the equator. In the surface layer, gut pheopigment minima were observed during the day, and maxima at night. This pattern clearly followed the periodicity of diel vertical migration, with intense feeding observed after the main upward ascent around sunset. Conversely, the feeding pattern in the integrated water column was more related to food abundance with a higher feeding during the day and around sunset, especially at the equator. Gut pigment contents in the water column displayed late afternoon maxima and dawn minima, coinciding with the maxima and minima of depth-integrated chlorophyll a (chl a). On the basis of standing stocks of chl a containing particles larger than 3 ?m, mean grazing pressure (i.e., specific grazing rates multiplied by copepod dry weights and divided by in situ chl a) varied between 3.0 and 4.0% in the upper 100 m and between 3.5 and 3.8% in the neuston layer. Because of the cyclical nature of feeding activities, short-term variability in grazing pressure estimates were substantial, with individual estimates ranging from a high of 17.5% d-1 to a low of 0.2% d-1 in the neuston layer and from 0.9 to 7.8% d-1 in the 0-100 m water column.

Champalbert, GisèLe; Neveux, Jacques; Gaudy, Raymond; Le Borgne, Robert

2003-12-01

400

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

401

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

402

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

403

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

PubMed

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

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

2014-07-01

404

Distribution of pigment dispersing hormone- and tachykinin-related peptides in the central nervous system of the copepod crustacean Calanus finmarchicus.  

PubMed

Peptides represent the largest class of signaling molecules used by nervous systems, functioning as locally-released paracrines and circulating hormones in both invertebrates and vertebrates. While many studies have focused on elucidating pepti