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Trophic impact, metabolism, and biogeochemical role of the marine cladoceran Penilia avirostris and the co-dominant copepod Oithona nana in NW Mediterranean coastal waters  

Microsoft Academic Search

In this work we studied the trophic ecology and feeding impact of the cladoceran Penilia avirostris and the cyclopoid copepod Oithona nana, the two dominant zooplankters in the summer communities of the coastal NW Mediterranean, on the naturally occurring microbial communities. In order to ascertain carbon surplus for growth and reproduction and the contribution to carbon and nitrogen recycling of

Dacha Atienza; Albert Calbet; Enric Saiz; Miquel Alcaraz; Isabel Trepat



Community structure and vertical distribution of cyclopoid copepods in the Red Sea  

Microsoft Academic Search

The species abundance, vertical distribution and diurnal vertical migration of cyclopoid copepods was analyzed in the central Red Sea in October–November 1980. Samples were taken to a depth of 450 m with a multiple opening — closing plankton net with 0.1-mm mesh-size. Selected important species were allocated to five different groups according to their depth distributions during daytime. The greatest

R. Böttger-Schnack




Microsoft Academic Search

Zooplankton samples from the Sacramento-San Joaquin Estuary collected by the California Department of Fish and Game and the United States Geological Survey were examined for cyclopoid copepods of the family Oithonidae. Of the three species found, Limnoithona sinensis, Oithona davisae, new species, and O. similis, the first two are described here, Lim- noithona sinensis, like its congener L. telraspina, has

Frank D. Ferrari; James Orsi


The effect of temperature on the development, reproduction, and longevity of two common cyclopoid copepods — Eucyclops serrulatus (Fischer) and Cyclops strenuus (Fischer)  

Microsoft Academic Search

The embryonic and postembryonic development times, time interval between clutches, and longevity of two common cyclopoid copepods — Eucyclops serrulatus and Cyclops strenuus — were studied at constant temperatures (5°, 10°, 15°, 20° and 25 °C), using algae and protozoans as food.

Gerhard Maier



Effect of culture density and antioxidants on naupliar production and gene expression of the cyclopoid copepod, Paracyclopina nana.  


Although attempts have been made to use mass cultures of marine copepods as live foods in marine aquaculture, some limitations such as low density culture still exist. The brackish water cyclopoid copepod, Paracyclopina nana has the potential for mass culturing as live food. In this study, we not only investigated the effect of culture density on the naupliar production and specific gene expressions of P. nana, but also the effect of several antioxidants under the conditions of a high density culture. The naupliar production of the copepod decreased with increasing culture density. The expression of glutathione reductase (GR), selenium-dependent glutathione peroxidase (SeGPx), glutathione S-transferase kappa (GST kappa), heat shock protein 40 (Hsp40), and Hsp70 genes of P. nana increased in the high density treatment but vitellogenin genes (Vg1 and Vg2) showed downregulation. In the condition with 20 inds./mL, vitamin C had a significant decrease but sodium selenite induced the naupliar production of P. nana greatly. The expressions of GR, SeGPx, Hsp70, and Vg genes increased with the vitamin C treatment. Sodium selenite caused a decrease of SeGPx and Hsp40 but GST kappa increased in the treatment with 20 inds./mL. These results suggest that sodium selenite is a positive antioxidant which can increase the culture efficiency of the copepod. PMID:22062798

Lee, Kyun-Woo; Rhee, Jae-Sung; Han, Jeonghoon; Park, Heum Gi; Lee, Jae-Seong



Intrahost distribution and transmission of a new species of cyclopoid copepod endosymbiotic to a freshwater snail, Pomacea canaliculata (Caenogastropoda, Ampullariidae), from Argentina.  


A new species of cyclopoid copepod, Ozmana huarpium, is described as a symbiont to Pomacea canaliculata (Lamarck 1822) (Caenogastropoda, Ampullariidae). Rather large numbers (about one hundred copepods per snail) were found, although there was no evidence of harm to the host. To our knowledge, O. haemophila (symbiont to P. maculata), and the currently described species, O. huarpium, are the only copepod species ever recorded as endosymbionts to freshwater invertebrates. While O. haemophila is restricted to the haemocoel of its host, O. huarpium predominate in the penis sheath, the ctenidium and the mantle cavity, figuring in these pallial organs 63-65% of total mature forms. The sex ratio of the symbiont is skewed to the female side in these organs, specially in male hosts. The hypothesis that a special female tropism for the male host's pallial organs might ensure interindividual transmission of the symbiont was tested, with indications that the symbiont is mainly transmitted during copulation. PMID:15462567

Gamarra-Luques, C D; Vega, I A; Koch, E; Castro-Vazquez, A




Microsoft Academic Search

3 San Juan Laboratories, P.O. Box 364532, San Juan, PR 00936-4532 ABSTRACT. A simple method for indoor and outdoor cultivation of Mesocyclops aspericornis, Macrocyclops albidus and Mesocyclops n. sp. copepods is presented. This method utilizes Chilomonas sp., Paramecium caudatum and fresh lettuce as food sources for copepod cultures. Steps for initiating and maintaining copepod cultures are provided. Cyclopoid copepods (planktonic



Feeding of copepods on natural suspended particles in Tokyo Bay  

Microsoft Academic Search

Community grazing rates of copepods were estimated from data taken during three cruises in Tokyo Bay, based on bottle incubations and a temporal variation of gut fluorescence. Special attention was paid to the feeding selectivity in the estimations. Differential grazing was observed in the copepod communities:Acartia omorii, abundant in February, selectively fed on the particles of dominant size classes, whileOithona

Atsushi Tsuda; Takahisa Nemoto



Life cycle strategies of free-living copepods in fresh waters  

Microsoft Academic Search

Freshwater copepods live in habitats characterized by a high degree of instability. To survive occasional deterioration of their environment copepods have evolved adaptive mechanisms like dormancy or migration in order to avoid lethal conditions and to synchronize growth and reproduction with favourable abiotic and biotic conditions. Typical life cycles of harpacticoid, calanoid and cyclopoid copepods are presented to show strategies

Barbara Santer



The relationship between genome size, development rate, and body size in copepods  

Microsoft Academic Search

Freshwater cyclopoid copepods exhibit at least a fivefold range in somatic genome size and a mechanism, chromatin diminution, which could account for much of this interspecific variation. These attributes suggest that copepods are well suited to studies of genome size evolution. We tested the nucleotypic hypothesis of genome size evolution, which poses that variation in genome size is adaptive due

Grace A. Wyngaard; Ellen M. Rasch; Nicole M. Manning; Kathryn Gasser; Rickie Domangue



The sequential taxonomic key: an application to some copepod genera  

Microsoft Academic Search

A new key based on sequentially numbered statements and alphanumeric words has been developed for the adults of North American freshwater calanoid and cyclopoid copepod genera. This sequential key is easy to use because the main characters being used for separating subgroups are expressed by alphanumeric words. Thus, shorter and fewer sentences are necessary than with the conventional dichotomous key.

Zinntae Zo



Production of tropical copepods in Kingston Harbour, Jamaica: the importance of small species  

Microsoft Academic Search

The copepod community observed during an 18-month period at the mouth of eutrophic Kingston Harbour, Jamaica, was dominated\\u000a by small species of Parvocalanus, Temora, Oithona, and Corycaeus. Mean copepod biomass was 22.1 mg AFDW m?3 (331 mg m?2). Annual production was 1679 kJ m?2, partitioned as 174 kJ m?2 naupliar, 936 kJ m?2 copepodite, 475 kJ m?2 egg and 93

R. R. Hopcroft; J. C. Roff; D. Lombard



The potential of certain indigenous copepod species as live food for commercial fish larval rearing  

Microsoft Academic Search

In the search for potential indigenous live food organisms for fish larval rearing, Zooplankton samples were collected from a shallow coastal lagoon, facing the South China Sea during the dry monsoon (May–September 1991) and the wet monsoon (November–April 1992) seasons. The dominant copepod in the Zooplankton community, Oithona sp., accounted for more than 70% of the total Zooplankton during the

Lokman Shansudin; M. Yusof; A. Azis; Y. Shukri



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


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

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



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

Microsoft Academic Search

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

R. C. Hart



The effect of temperature on reproduction in three species of cyclopoid copepods  

Microsoft Academic Search

Megacyclops viridis (Jurine), Macrocyclops albidus (Jurine), and Acanthocyclops vernalis (Fischer) were raised in the laboratory at six temperatures (5, 8, 10, 12, 15 and 20°) and fed a mixture of ciliates (Paramecium caudatum and Colpidium campylum). Data were taken on clutch size, embryonic development time, interclutch period, time to first clutch, sex ratio and longevity.

Bukar A. Abdullahi



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

USGS Publications Warehouse

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

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



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

NASA Astrophysics Data System (ADS)

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

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



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.



How coastal upwelling influences spatial patterns of size-structured diversity of copepods off central-southern Chile (summer 2009)  

NASA Astrophysics Data System (ADS)

This study assessed the structure of the copepod community in the upper 200 m of the coastal upwelling region off central-southern Chile in late summer 2009. Vertically stratified zooplankton samples and hydrographic variables were obtained from 42 stations over the continental shelf and oceanic areas. The survey took place during active upwelling, reflected by a cold upwelling plume extending out to 150 km offshore. A total of 62 copepod species were found. Of these, Oithona similis and Paracalanusindicus accounted for ca. 60% of the whole community. Species richness (R) and the Shannon-Wiener diversity index (H?) were estimated, and the latter was additionally modified to incorporate the effect of copepod size on diversity (H?s). Samples were analyzed for two depth strata (0-50, 50-200 m) and for day vs. night conditions. Significant effects of day vs. night and strata on R, H? and H?s indicated that diel vertical migration between these two layers was an important source of variation in the zooplankton community. H?s seemed to represent copepod diversity better than R and H? over the spatial scale. H?s was also closely linked to colder upwelled water and the depth of the oxygen minimum zone following a principal component analysis. A positive relationship was even detected between depth of the oxygen minimum zone and H?s when strata and day/night effects were excluded. Our findings suggested that the coastal upwelling process could be an important driver of copepod diversity in this region. Upwelling leads to changes in the depth of the oxygen minimum zone and these changes impact the community composition due to species-dependent tolerances to low oxygen water.

Hidalgo, Pamela; Escribano, Ruben; Fuentes, Marcelo; Jorquera, Erika; Vergara, Odette



Harpacticoid and cyclopoid fauna of groundwater and springs in southern Finland  

Microsoft Academic Search

The groundwater fauna, of which scarcely anything has previously been studied in formerly glaciated areas, was richest close to the water table and diminished markedly at greater depths. However, few individuals were generally recorded per 1 m3 of water. Bryocamptus minutus was the most abundant species of copepod at an esker site, the other species recorded being Attheyella crassa, Bryocamptus

Jukka Särkkä; Leena Levonen; Jorma Mäkelä



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.

Ceballos, Sara; Ki?rboe, Thomas



Senescence and sexual selection in a pelagic copepod.  


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



A new genus of endoparasitic copepods (Cyclopoida: Enterognathidae), forming a gall in the calyx of deep-sea crinoids.  


A new genus and species of cyclopoid copepod belonging to the family Enterognathidae, Parenterognathus troglodytes, is described from a gall on the calyx of the deep-sea crinoid Glyptometra crassa (Clark, 1912) collected at depths of 775-787 m off Kumano-nada, middle Japan. The new genus can be distinguished from the three known genera of the family by body tagmosis and by the segmentation and armature of the appendages. This is the first record of this family from the Pacific Ocean. This family seems to be host-specific to relatively basal deuterostomes, such as echinoderms and hemichordates. The evolutionary transformation and history of the Enterognathidae are briefly discussed. PMID:20695785

Ohtsuka, Susumu; Kitazawa, Kota; Boxshall, Geoffrey A



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

NASA Astrophysics Data System (ADS)

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

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



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.



A new species of the rare endoparasitic copepod Entobius (Copepoda: Entobiidae) from Mexico with a key to the species of the genus.  


Abstract: In a study of the benthic polychaete fauna of the southern Gulf of Mexico and the Caribbean Sea, several specimens of the terebellid polychaete Scionides reticulata (Ehlers) were found to host endoparasitic copepods that represent an undescribed species of the rare cyclopoid genus Entobius Dogiel, 1948. The new species, E. scionides sp. n., can be distinguished from its congeners by a combination of characters including a genital region without constrictions, three-segmented antennules, a reduced antenna with a blunt terminal process, reduced ornamentation of endopods of legs 1-4 and its relatively small size (2.3-2.7 mm). It is the smallest species of the genus. Comments on immature females are also provided, but males of this species remain unknown. It has a high prevalence (53%) in populations of the terebellid S. reticulata in the southern Gulf of Mexico, but it is absent from the Caribbean. This is the first occurrence of this copepod genus in the Americas. The finding of the new species of Entobius in S. reticulata confirms the strict specificity of most members of the genus and expands the host range of this copepod genus. A key for the identification of the species of Entobius is provided. PMID:23136803

Suárez-Morales, Eduardo; Carrera-Parra, Luis F



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.



Checklist of copepods from Gulf of Nicoya, Coronado Bay and Golfo Dulce, Pacific coast of Costa Rica, with comments on their distribution.  


A list of 54 copepod species (Crustacea) in 23 families is presented for the Pacific coast of Costa Rica. Identifications are from zooplankton samples of the Victor Hensen Expedition during December 1993 and February 1994. Samples were taken with a Bongo net (0.60 m net opening, 2.50 m net length) with 200 microns mesh size. Oblique hauls were done from the surface to the ground at a towing speed of aprox. 1 knot. 37 species (68.5%) were found in the Gulf of Nicoya, 36 in Golfo Dulce (66.6%) and 17 (31.4%) species were common to both gulfs, while only twelve species (22.2%) were found in Coronado Bay. Four species (7.4%) were distributed along the coast and were common to the three regions: Paracalanus parvus, Euchaeta sp., Oithona plumifera and O. similis. Eleven species of calanoids found normally in the Costa Rica Dome show the influence of typical oceanic waters principally at the mouth of Gulf of Nicoya. Differences were observed in the composition and presence of the copepod species when the inner and outer (upper and lower) parts of both gulfs were compared. Gulf of Nicoya was dominated in its upper part by typical neritic estuarine species like Acartia lilljenborgii, Paracalanus parvus and, Hemyciclops thalassius as well as species of Pseudodiaptomus. On the other hand a more oceanic composition of copepods was observed in the lower part of the gulf. Both small species, like Oncaea venusta, as well as larger species, such as Pleuromamma robusta, Eucalanus attenuatus, E. elongatus and Rhincalanus nasutus, were typical of these waters. Oithona plumifera and O. similis were found in the lower part too; and both species are typical from oceanic water. Coronado Bay was characterized by the presence of typical oceanic species like Neocalanus gracilis, Euchaeta longicornis, Eucalanus attenuatus and Haloptilus ornatus with more transitional species like Clausocalanus pergens and C. furcatus near the coast. In the Golfo Dulce differences in copepod composition were also observed, but the separation of the species was not so evident. Outer stations were represented by oceanic species like Paracalanus aculeatus, Pleuromamma gracilis, Lucicutia ovalis, Candacia catula, Euchaeta wolfendeni and Oncaea mediterranea, while the inner station, located at the upper part of the Gulf, was more characterized by a mixed copepod group, with both neritic species like Pseudodiaptomus wrigthi, Acartia danae, A. clausi, Canthocalanus pauper as well as oceanic species like Scolicithricella marginata, Saphirina nicromaculata or Oncaea conifera. Two species of Coryceaus, C. flaccus and C. speciosus, were identified in the outer stations of Golfo Dulce, while C. brehmi was found in inner stations of Gulf of Nicoya. The majority of copepods found are typical of the east Pacific. This paper constitutes an additional work about the copepods in the Gulf of Nicoya and the first report of copepod species for Coronado Bay and Golfo Dulce. PMID:9393648

Morales-Ramírez, A



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

PubMed Central

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

Cepeda, Georgina D.; Blanco-Bercial, Leocadio; Bucklin, Ann; Beron, Corina M.; Vinas, Maria D.



Optimal mate choice patterns in pelagic copepods.  


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

Heuschele, Jan; Eliassen, Sigrunn; Kiørboe, Thomas



Hydrocarbon Contamination Decreases Mating Success in a Marine Planktonic Copepod  

Microsoft Academic Search

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

Laurent Seuront



A plea for the use of copepods in freshwater ecotoxicology.  


Standard species used in ecological risk assessment are chosen based on their sensitivity to various toxicants and the ease of rearing them for laboratory experiments. However, this mostly overlooks the fact that species in the field that may employ variable life-history strategies, which may have consequences concerning the vulnerability of such species to exposure with contaminants. We aimed to highlight the importance of copepods in ecology and to underline the need to include freshwater copepods in ecotoxicology. We carried out a literature search on copepods and Daphnia in ecology and ecotoxicology to compare the recognition given to these two taxa in these respective fields. We also conducted a detailed analysis of the literature on copepods and their current role in ecotoxicology to characterize the scale and depth of the studies and the ecotoxicological information therein. The literature on the ecology of copepods outweighed that in ecotoxicology when compared with daphnids. Copepods, like other zooplankton, were found to be sensitive to toxicants and important organisms in aquatic ecosystems. The few studies that were conducted on the ecotoxicology of copepods mainly focused on marine copepods. However, very little is known about the ecotoxicology of freshwater copepods. To enable a more realistic risk higher tier environmental risk assessment, we recommend considering freshwater copepods as part of the hazard assessment process. This could include the establishment of laboratory experiments to analyse the effects of toxicants on copepods and the development of individual-based models to extrapolate effects across species and scenarios. PMID:22899440

Kulkarni, Devdutt; Gergs, André; Hommen, Udo; Ratte, Hans Toni; Preuss, Thomas G



Algal Toxins Alter Copepod Feeding Behavior  

Microsoft Academic Search

Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of

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



Copepod hatching success in marine ecosystems with high diatom concentrations  

Microsoft Academic Search

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

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



Copepod feeding currents: Food capture at low Reynolds number1  

Microsoft Academic Search

High-speed motion pictures of dye streams around feeding Calanoid copepods revealed that these important planktonic herbivores do not strain algae out of the water as previously described. Rather, a copepod flaps four pairs of feeding appendages to propel water past itself and uses its second maxillae to actively capture parcels of that water containing food particles. The feeding appendages of

M. A. R. Koehl; J. Rudi Strickler



Respiration in marine pelagic copepods: a global-bathymetric model  

Microsoft Academic Search

Historical global respiration datasets of epipelagic copepods and recent bathymetric respiration datasets of mesopelagic, upper- and lower-bathypelagic and abyssopelagic copepods were combined to build a global-bathymetric respiration model by adopting 2 regression models (theoretical and empirical ones). Designated independent variables including body mass (expressed as dry mass, carbon or nitrogen), habitat temperature, ambient oxygen saturation and the depth of occurrence

Tsutomu Ikeda; Fumikazu Sano; Atsushi Yamaguchi



Microbial food partitioning by three species of benthic copepods  

Microsoft Academic Search

Using radioactively labeled bacteria and photoautotrophs in undisturbed sediment cores, we show that three cooccurring species of benthic copepods feed on different microbial food sources in their natural environment. Specifically, Thompsonula hyaenae feeds on photoautotrophs, Halicyclops coulli feeds on bacteria, and Zausodes arenicolus feeds on both photoautotrophs and bacteria. Species of benthic copepods feed differently from one another in the

K. R. Carman; D. Thistle



Locomotion in copepods: pattern of movements and energetics of Cyclops  

Microsoft Academic Search

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

M. Alcaraz; J. R. Strickler



Sexual dimorphism in calanoid copepods: morphology and function  

Microsoft Academic Search

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

Susumu Ohtsuka; Rony Huys



Molecular and microscopic evidence of viruses in marine copepods.  


As dominant members of marine mesozooplankton communities, copepods play critical roles in oceanic food webs and biogeochemical cycling. Despite the ecological significance of copepods, little is known regarding the causes of copepod mortality, and up to 35% of total copepod mortality cannot be accounted for by predation alone. Viruses have been established as ecologically important infectious agents in the oceans; however, viral infection has not been investigated in mesozooplankton communities. Here we used molecular and microscopic techniques to document viral infection in natural populations of the calanoid copepods Acartia tonsa (Dana) and Labidocera aestiva (Wheeler) in Tampa Bay, FL. Viral metagenomics revealed previously undocumented viruses in each species, named Acartia tonsa copepod circo-like virus (AtCopCV) and Labidocera aestiva copepod circo-like virus (LaCopCV). LaCopCV was found to be extremely prevalent and abundant in L. aestiva populations, with up to 100% prevalence in some samples and average viral loads of 1.13 × 10(5) copies per individual. LaCopCV transcription was also detected in the majority of L. aestiva individuals, indicating viral activity. AtCopCV was sporadically detected in A. tonsa populations year-round, suggesting temporal variability in viral infection dynamics. Finally, virus-like particles of unknown identity were observed in the connective tissues of A. tonsa and L. aestiva by transmission electron microscopy, demonstrating that viruses were actively proliferating in copepod connective tissue as opposed to infecting gut contents, parasites, or symbionts. Taken together, these results provide strong independent lines of evidence for active viral infection in dominant copepod species, indicating that viruses may significantly influence mesozooplankton ecology. PMID:23297243

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



Copepods grazing on Coscinodiscus wailesii: a question of size?  

NASA Astrophysics Data System (ADS)

Grazing of female copepods, Acartia clausi and Temora longicornis, on the large centric diatom Coscinodiscus wailesii, was studied in the laboratory. While A. clausi females did not feed on C. wailesii, T. longicornis showed a skilful handling of these large algae. The cells were not completely ingested but copepods bit a small piece out of the silica wall and then ingested the cell content only. Faecal pellet analyses showed little remains of the silica walls, and most of the content could only be classified as undefined matter. Therefore the general analyses of faecal pellets and gut content of copepods from the field must be interpreted with caution.

Jansen, Sandra



The Distribution of Calanoid Copepods in the Great Lakes.  

National Technical Information Service (NTIS)

The geographical distribution of the ten calanoid copepods in the Great Lakes has been studied through a synthesis of the previously published identifications with a limited number of original determinations. Six species, Diaptomus ashlandi, D. minutus, D...

A. Robertson



A continuous recirculating culture system for planktonic copepods  

Microsoft Academic Search

The calanoid copepods, Acartia clausiGiesbrecht and Acartia tonsaDana, are maintained at high densities in continuous culture at 15°C. Synthetic sea-water medium is recirculated through filters and a foam tower which limits accumulation of dissolved wastes and various metabolites. The ciliate Euplotes vannusMüller is associated in culture with the copepods, and effectively controls bacterial population and accumulation of algal debris. The

E. J. Zillioux



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.

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



Hydrocarbon contamination decreases mating success in a marine planktonic copepod.  


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



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.

Seuront, Laurent



What Copepods Can Tell us About Epikarst Hydrology  

NASA Astrophysics Data System (ADS)

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

Culver, D. C.; Pipan, T.



A simple method for cultivating freshwater copepods used in biological control of Aedes aegypti.  


A simple method for indoor and outdoor cultivation of Mesocyclops aspericornis, Macrocyclops albidus and Mesocyclops n. sp. copepods is presented. This method utilizes Chilomonas sp., Paramecium caudatum and fresh lettuce as food sources for copepod cultures. Steps for initiating and maintaining copepod cultures are provided. PMID:1474389

Suarez, M F; Marten, G G; Clark, G G



Rearing West Australian seahorse, Hippocampus subelongatus, juveniles on copepod nauplii and enriched Artemia  

Microsoft Academic Search

Improved captive breeding techniques are required for seahorses. Artemia nauplii are generally considered a poor first feeding diet for many seahorse species. This study compared growth and survival of newborn Hippocampus subelongatus reared on cultured copepod nauplii and Artemia nauplii enriched with Super Selco®. Early growth and survival of seahorses were significantly greater when fed copepod nauplii. Copepod nauplii were

M. F Payne; R. J Rippingale



Gene expression patterns and stress response in marine copepods.  


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

Lauritano, Chiara; Procaccini, Gabriele; Ianora, Adrianna



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.

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



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



Dissolution of coccolithophorid calcite by microzooplankton and copepod grazing  

NASA Astrophysics Data System (ADS)

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

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



Ecological significance of individual variability in copepod bioenergetics  

Microsoft Academic Search

High interstage variability in body length and mass, reproductive state, and metabolic activity is characteristic of copepod populations from the Barents Sea and coastal waters in Sweden and Norway. The dry weight of a given copepodite stage, sampled at a given time from a homogeneous water mass, may vary by a factor of 4–5 between extreme individuals, protein and particularly

Ulf Båmstedt



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

Friedman, M M; Strickler, J R



Colonization of the pelagic realm by calanoid copepods  

Microsoft Academic Search

The evolution of calanoid copepods probably extends back into the mid-Paleozoic. Environmental change from the Paleozoic through to the Tertiary is reviewed. Turbidity, water clarity, oxygen, pelagic primary production, and tectonically induced changes in the morphology of the oceans are probably all important drivers of calanoid evolution and their invasion of the pelagic realm. Current views of the phylogeny of

Janet M. Bradford-Grieve



Extent and Nature of Stress on Copepod Populations.  

National Technical Information Service (NTIS)

Among populations of the copepod Eurytemora affinis grown in three constant (10, 15, 23C) and three variable environments, more genetic adaptation occurred in a temperature regime cycling at 1 degree per day than in a regime cycling at 1 degree per week o...

B. P. Bradley



Responses of Copepod Individuals and Populations to Increased Temperature Variability.  

National Technical Information Service (NTIS)

Emphasis in this study was placed on field studies of populations of two species of copepods, Eurytemora affinis (EA) and Acartia tonsa (AT), in the vicinity of two power plants. The study sought to identify the effects of waste heat on local population d...

B. P. Bradley



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



High Speed Tomographic PIV Measurements of Copepod Sensory Cues  

NASA Astrophysics Data System (ADS)

A steady siphon flow is commonly used to mimic the aquatic suction feeding of piscine predators in studies of zooplankton sensory ecology. The sensory and escape behavior of copepods, with their long, highly enervated, setae-bearing antennules, has been investigated using this prescribed flow field, modeled analytically as a point sink. The position of the animal when it escapes provides a threshold for the species-specific strain rate value (as low as 0.4 s-1) that evokes this ecologically-important behavior. Understanding the actual mechanics of copepod sensing, however, requires more than just correlation analysis based on position in the strain rate field. Knowledge of the setae-bending flow field along the length of the antennules during the time leading up to the escape jump is needed to fully understand the sensory mechanism. Measurements of this type have not been practical using traditional planar PIV techniques. We present time-resolved tomographic PIV measurements of the flow around the sensory appendages of Acartia spp. copepods responding to siphon flow and provide insight into copepod behavior in response to fluid mechanical stimuli.

Webster, Donald R.; Murphy, David; Yen, Jeannette



Do Inactivated Microbial Preparations Improve Life History Traits of the Copepod Acartia tonsa ?  

Microsoft Academic Search

We have tested a microbial preparation with probiotic effects (PSI; Sorbial A\\/S DANISCO) on the calanoid copepod Acartia tonsa (Dana) development time and reproduction effectiveness in culture. The hypotheses were that PSI increases the productivity\\u000a and quality of copepods in culture (increased egg production and hatching success, HS). This was carried out because the use\\u000a of copepods as live prey

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


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



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

Microsoft Academic Search

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

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



Production and fate of copepod fecal pellets across the Southern Indian Ocean  

Microsoft Academic Search

The vertical distribution of copepods, fecal pellets and the fecal pellet production of copepods were measured at seven stations\\u000a across the Southern Indian Ocean from productive areas off South Africa to oligotrophic waters off Northern Australia during\\u000a October\\/November 2006. We quantified export of copepod fecal pellet from surface waters and how much was retained. Furthermore,\\u000a the potential impact of Oncaea

Eva Friis Møller; Christian Marc Andersen Borg; Sigrún H. Jónasdóttir; Suree Satapoomin; Cornelia Jaspers; Torkel Gissel Nielsen



Copepods induce paralytic shellfish toxin production in marine dinoflagellates  

PubMed Central

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

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



The assimilation of elements ingested by marine copepods  

SciTech Connect

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

Reinfelder, J.R.; Fisher, N.S. (State Univ. of New York, Stony Brook (United States))



Horizontal distribution of calanoid copepods in the western Arctic Ocean during the summer of 2008  

NASA Astrophysics Data System (ADS)

The horizontal distribution of the epipelagic zooplankton communities in the western Arctic Ocean was studied during August-October 2008. Zooplankton abundance and biomass were higher in the Chukchi Sea, and ranged from 3,000 to 274,000 ind. m-2 and 5-678 g WM m-2, respectively. Copepods were the most dominant taxa and comprised 37-94% of zooplankton abundance. For calanoid copepods, 30 species belonging to 20 genera were identified. Based on the copepod abundance, their communities were classified into three groups using a cluster analysis. The horizontal distribution of each group was well synchronized with depth zones, defined here as Shelf, Slope and Basin. Neritic Pacific copepods were the dominant species in the Shelf zone. Arctic copepods were substantially greater in the Slope zone than the other regions. Mesopelagic copepods were greater in the Basin zone than the other regions. Stage compositions of large-sized Arctic copepods (Calanus glacialis and Metridia longa) were characterized by the dominance of late copepodid stages in the Basin. Both the abundance and stage compositions of large copepods corresponded well with Chl. a concentrations in each region, with high Chl. a in the Shelf and Slope supporting reproduction of copepods resulting in high abundance dominated by early copepodid stages.

Matsuno, Kohei; Yamaguchi, Atsushi; Shimada, Koji; Imai, Ichiro




Microsoft Academic Search

Eight ~pecic~ of ealanoid copepods ha,'c now been rcported from Oklahoma. Two of thl'5C, Diaptomlls a\\/buqllcrqucmis and D. dorsalis, are reported here for the fiut time. The Ii ~pccies arc all mcmocrs of thc genus Diaptomlls, but 6 differcnt subgenera arc rcprl'5ellted. No sp<:c;e5 ha~ been fonnd throughout thc state, although D. pal\\/idu5 ~cm, to OCCIl1 cn:rywherc exeept in a

Andrew Robertson


The insidious effect of diatoms on copepod reproduction  

NASA Astrophysics Data System (ADS)

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

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



The need for speed. II. Myelin in calanoid copepods.  


Speed of nerve impulse conduction is greatly increased by myelin, a multi-layered membranous sheath surrounding axons. Myelinated axons are ubiquitous among the vertebrates, but relatively rare among invertebrates. Electron microscopy of calanoid copepods using rapid cryofixation techniques revealed the widespread presence of myelinated axons. Myelin sheaths of up to 60 layers were found around both sensory and motor axons of the first antenna and interneurons of the ventral nerve cord. Except at nodes, individual lamellae appeared to be continuous and circular, without seams, as opposed to the spiral structure of vertebrate and annelid myelin. The highly organized myelin was characterized by the complete exclusion of cytoplasm from the intracellular spaces of the cell generating it. In regions of compaction, extracytoplasmic space was also eliminated. Focal or fenestration nodes, rather than circumferential ones, were locally common. Myelin lamellae terminated in stepwise fashion at these nodes, appearing to fuse with the axolemma or adjacent myelin lamellae. As with vertebrate myelin, copepod sheaths are designed to minimize both resistive and capacitive current flow through the internodal membrane, greatly speeding nerve impulse conduction. Copepod myelin differs from that of any other group described, while sharing features of every group. PMID:10798723

Weatherby, T M; Davis, A D; Hartline, D K; Lenz, P H



Global latitudinal variations in marine copepod diversity and environmental factors.  


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

Rombouts, Isabelle; Beaugrand, Grégory; Ibanez, Frédéric; Gasparini, Stéphane; Chiba, Sanae; Legendre, Louis



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.

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



Identification of immune genes in grass carp Ctenopharyngodon idella in response to infection of the parasitic copepod Sinergasilus major  

Microsoft Academic Search

The parasitic copepod Sinergasilus major is an important pathogen of grass carp Ctenopharyngodon idella. To understand the immune response of grass carp to the copepod infection, suppression subtractive hybridization method was employed to characterize genes up-regulation during the copepod infection in liver and gills of the fish. One hundred and twenty-two dot blot positive clones from infected subtracted library were

M. X. Chang; P. Nie; G. Y. Liu; Y. Song; Q. Gao



Feeding of calanoid copepods in relation to Phaeocystis pouchetii blooms in the German Wadden Sea area off Sylt  

Microsoft Academic Search

Population dynamics of the dominant calanoid copepods Acartia spp. and Tempora longicornis were followed during a dense spring bloom of Phaeocystis pouchetii in the northern Wadden Sea off Sylt. Positive correlations between algal concentration and abundance of the copepod species suggest that P. pouchetii constitutes an important food organism for the copepods in spring and early summer. In laboratory experiments,

T. Weiße



Survival and diapause egg production of the copepod Centropages hamatus raised on dinoflagellate diets  

Microsoft Academic Search

Copepods are often said to require a mixed diet to maximize their survival and reproduction potential. Copepods may be forced to feed nonselectively in food limited environments, but this does not mean they require a diverse diet. In this study, we show that the right single food item, at the right stage, can be as good or better than a

Margaret M Murray; Nancy H Marcus



Temporal control of DNA replication and the adaptive value of chromatin diminution in copepods  

Microsoft Academic Search

Chromatin diminution is a precisely controlled, highly repeatable, genome-wide deletion of noncoding heterochromatic segments from the presomatic line. The somatic line is reduced in size and reorganized; the germ line remains unaltered. Little is understood about its mechanistic underpinnings and adaptive significance in the nematodes, copepods, and hagfish in which it occurs. Here, we propose that microcrustacean copepods, whose cytology,

Grace A. Wyngaard; T. Ryan Gregory



Asterocheres crinoidicola n. sp., a copepod (Siphonostomatoida: Asterocheridae) parasitic on crinoids in Belize.  


A new species of siphonostomatoid copepod, Asterocheres crinoidicola, is parasitic on two closely related comasterid crinoids (Nemaster grandis and Davidaster rubiginosus) in Belize, Central America. An unusually long terminal prolongation of the third segment of the endopod of leg 1 distinguishes this species from all congeners. This is the first report of a copepod parasitic on a crinoid in the Caribbean. PMID:10966217

Humes, A G



Egg production of the copepod Acartia tonsa: The influence of hypoxia and food concentration  

Microsoft Academic Search

Low dissolved oxygen conditions, or hypoxia, occur in estuaries and impact more than just the obvious commercially important species. Copepods are an important link in the food web, and the influence of hypoxia upon them is relatively unstudied. Using the copepod Acartia tonsa, a study of the impact of hypoxia on egg production was conducted. A. tonsa had reduced egg

Chris Sedlacek; Nancy H. Marcus



Status and recommendations on marine copepod cultivation for use as live feed  

Microsoft Academic Search

Copepods are important crustaceans studied because of their key role in ecology, trophic biology, fisheries management, in modeling the flow of energy and matter, ecotoxicology, aquaculture and aquarium trade. This paper discusses various aspects of the state of knowledge of copepod culture at large scales and provides the scientific community with ideas and concepts that could improve and quicken the

Guillaume Drillet; Stéphane Frouël; Mie H. Sichlau; Per M. Jepsen; Jonas K. Højgaard; Almagir K. Joarder; Benni W. Hansen



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

Microsoft Academic Search

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

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



Dissolved solids do not induce diapause in the calanoid copepod Aglaodiaptomus leptopus  

Microsoft Academic Search

The effect of different total dissolved solid levels (TDS) was investigated as a predictor of diapause induction in the calanoid copepod Aglaodiaptomus leptopus. We collected adult copepods in the field and monitored seasonal changes in diapause egg production. We determined total dissolved solid levels, conductivity and temperature values from five ponds. In experimental work, females bearing clutches, collected from the

Steve S. Di Lonardo; Edward J. Maly



Copepod feeding behaviour and egg production during a dinoflagellate bloom in the North Sea  

Microsoft Academic Search

Feeding strategies of copepods were studied during a dinoflagellate-dominated bloom in the North Sea in August 2001. The aim of this study was to evaluate the importance of mesozooplankton grazing as a biological loss factor of harmful algal blooms under natural conditions. Therefore, ingestion, egestion and egg production experiments were performed with the most abundant copepod species Calanus helgolandicus, Temora

Sandra Jansen; Christian Wexels Riser; Paul Wassmann; Ulrich Bathmann



The use of egg shells to infer the historical presence of copepods in alpine lakes  

Microsoft Academic Search

Copepods (Class Crustacea, Order Copepoda) are rarely included in paleoecological studies of lakes because they lack long-lasting exoskeletal remains. We describe the remains of eggs (egg shells) from Hesperodiaptomus copepods that are well preserved and abundant in alpine lake sediments. We demonstrate that the egg shells are the remains of Hesperodiaptomus eggs based on (i) the similar size and morphology

Roland A. Knapp; Jodi A. Garton; Orlando Sarnelle



Hg bioaccumulation in marine copepods around hydrothermal vents and the adjacent marine environment in northeastern Taiwan.  


The Hg concentration in seawater and copepod samples collected from the area around hydrothermal vents at Kueishan Island and the adjacent marine environment in northeastern Taiwan were analyzed to study Hg bioaccumulation in copepods living in polluted and clean marine environments. The seawater collected from the hydrothermal vent area had an extremely high concentration of dissolved Hg, 50.6-256 ng l(-1). There was slightly higher Hg content in the copepods, 0.08-0.88 ?g g(-1). The dissolved Hg concentration in the hydrothermal vent seawater was two to three orders of magnitude higher than that in the adjacent environment. The bioconcentration factor of the studied copepods ranged within 10(3)-10(6), and showed higher dissolved concentration as the bioconcentration factor was lower. A substantial abundance, but with less copepod diversity was recorded in the seawater around the hydrothermal vent area. Temora turbinata was the species of opportunity under the hydrothermal vent influence. PMID:23932475

Hsiao, Shih-Hui; Fang, Tien-Hsi



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

NASA Astrophysics Data System (ADS)

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

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


Copepod feeding study in the upper layer of the tropical South China Sea  

NASA Astrophysics Data System (ADS)

The South China Sea (SCS) is the world’s largest marginal sea being notable for vertical mixing at various scales resulting in a sequence of chemical and biological dynamics in surface waters. We investigated the ingestion, gut content, evacuation and clearance rates of copepods collected from six stations (including a South East Asia Time Series station) along a transect line in the tropical of a SCS cruise during September 27, 1999 to October 2, 1999. The goal of the present study was to understand the feeding ecology of copepods in the upper water layers (0-5 m) of the northern SCS during autumn. We measured the gut pigment contents of 33 copepod species by the gut fluorescence method. The gut chlorophyll a values of most small size copepods (<1 mm) were lower than 1.00 ng Chl a individual-1. The highest gut pigment content was recorded in Scolecithrix danae (7.07 ng Chl a individual-1). The gut pigment contents of 33 copepod species (including 70 samples and 1,290 individuals) estimated is negatively correlated with seawater temperature (Pearson correlation r = -0.292, P = 0.014) and is positively correlated with the chlorophyll a concentration of ambient waters (Pearson correlation r = 0.243, P = 0.043). Mean gut pigment content, ingestion and clearance rates (from 80 samples and 1,468 individuals) show that larger copepods (>2 mm) had significantly higher values than medium sized copepods (1-2 mm) and smaller sized copepods. The present study shows that the performance of feeding on phytoplankton was variable in different sized copepod groups, suggesting that copepods obtained in the tropical area of the southeastern Taiwan Strait might be opportunistic feeders.

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



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.



Influences of metal concentration in phytoplankton and seawater on metal assimilation and elimination in marine copepods.  


Radiotracer experiments were conducted to examine the influence of the concentration of Cd, Se, and Zn in ingested phytoplankton (dinoflagellate Prorocentrum minimum and diatom Thalassiosira weissflogii) and in ambient seawater on metal assimilation and elimination efficiencies of three marine copepods, Acartia spinicauda, Paracalanus aculeatus, and Calanus sinicus. The assimilation efficiencies (AEs) decreased by 1.7 to 2.0 times, 1.4 to 4.1 times, and 1.3 to 2.2 times in the copepods with an increase in metal concentration in ingested algae by 16 to 84 times, 14 times, and 45 to 153 times, for Cd, Se, and Zn, respectively. However, the physiologic turnover rate constant was relatively independent of the metal concentration in copepods. No evidence was found of any interaction between Cd and Zn in their assimilation by copepods. Assimilation efficiencies of Cd were higher in copepods feeding on the dinoflagellate P. minimum, whereas the AEs of Zn were higher in copepods feeding on the diatom T. weissflogii. Differences in metal distribution in algal cytoplasm at different ambient metal concentrations may be partially responsible for the observed influence of metal concentration in algal cells on metal assimilation in copepods. However, metal desorption within the gut of the copepod may have little influence on metal assimilation, as a result of the short gut residence time of food particles and the neutral gut pH. Our study also indicated that the ingestion rate of copepods was reduced by a higher concentration of Cd and Se, but was not affected by Zn concentration in the food particles. Consequently, partial regulation of metal trophic transfer in response to increasing metal contamination may be achieved by a change in metal assimilation efficiency and the ingestion activity of the copepod, but not by changes in metal turnover rates from the animals. PMID:11337870

Xu, Y; Wang, W X; Hsieh, D P



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



Crustacean zooplankton assemblages in freshwaters of tropical Australia  

Microsoft Academic Search

Throughout tropical Australia eulimnetic zooplankton is composed of 7 calanoid copepods, 5 cyclopoid copepods and 12 cladocerans. A further 10 cyclopoids and 9 cladocerans occur as littoral ‘strays’, making 43 species in all. Dominants include Diaptomus lumholtzi, Mesocyclops notius, Thermocyclops decipiens, Diaphanosoma excisum, Ceriodaphnia cornuta, and Moina micrura. Momentary species composition averages 1.0 calanoids, 1.3 cyclopoids and 2.0 cladocerans. These

B. V. Timms; D. W. Morton



The feeding ecology of the copepod Centropages typicus (Kröyer)  

NASA Astrophysics Data System (ADS)

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

Calbet, Albert; Carlotti, François; Gaudy, Raymond



Mechanoreceptors in calanoid copepods: designed for high sensitivity.  


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

Weatherby, T M; Lenz, P H



Does sediment grain size affect diatom grazing by harpacticoid copepods?  


Estuarine soft sediments support a diverse group of eukaryotic and prokaryotic organisms though the role of the sediment per se for the functioning of these organisms remains largely unknown. The present study aimed to test the effect of sediment grain size on the grazing activities of harpacticoid copepods. In controlled experiments, two common intertidal harpacticoid species (Paramphiascella fulvofasciata and Nitokra spinipes) were each offered a mix of two benthic diatom species (Navicula phyllepta and Seminavis robusta) in different sedimentary conditions. Several microcosms were created using a variety of sediment types, including fine silt (<63 microm), coarser grained sands (125-250, 250-450, 100-300 microm), artificial 'sediments' of glass beads (250-500, 2000 microm) and even the absence of sediment was tested. The diatoms were enriched in the stable carbon (13)C to facilitate tracing in the harpacticoids. Both copepod species were able to graze on the diatoms with highest uptake when sediment was absent. In contrast, both harpacticoid species showed no uptake in silty conditions. In general, grazing was favoured when mean sediment grain size increased. The strong negative effect of fine grains on the grazer's efficiency can be explained by the resulting differences in the structure (and accessibility) of the diatom biofilm on the one hand and the mobility of the grazer on the other hand. In view of the subtle equilibrium between primary producers and grazers, these results might have important implications for the effect of siltation of tidal flats due to, e.g., human activities. PMID:16343608

De Troch, Marleen; Houthoofd, Lieven; Chepurnov, Victor; Vanreusel, Ann



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.



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


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

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



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


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



High-active truncated luciferase of copepod Metridia longa.  


The technology of real-time imaging in living cells is crucial for understanding of intracellular events. For this purpose, bioluminescent reporters have been introduced as sensitive and convenient tools. Metridia luciferase (MLuc) from the copepod Metridia longa is a coelenterazine-dependent luciferase containing a natural signal peptide for secretion. We report the high-active MLuc mutants with deletion of the N-terminal variable part of amino acid sequence. The MLuc variants were produced in Escherichia coli cells, converted to an active protein, and characterized. We demonstrate that the truncated MLucs have significantly increased bioluminescent activity as against the wild type enzyme but substantially retain other properties. One of the truncated variants of MLuc was transiently expressed in HEK 293 cells. The results clearly suggest that the truncated Metridia luciferase is well suited as a secreted reporter ensuring higher detection sensitivity in comparison with a wild type enzyme. PMID:22138240

Markova, Svetlana V; Burakova, Ludmila P; Vysotski, Eugene S



Adsorption of Vibrio parahaemolyticus onto Chitin and Copepods  

PubMed Central

Vibrio parahaemolyticus was observed to adsorb onto chitin particles and copepods. The efficiency of adsorption was found to be dependent on pH and on the concentration of NaCl and other ions found in seawater. Highest efficiency was observed in water samples collected from Chesapeake Bay and lowest in water from the open sea. V. parahaemolyticus was found to adsorb onto chitin with the highest efficiency of the several bacterial strains tested. Escherichia coli and Pseudomonas fluorescens did not adsorb onto chitin. The adsorption effect is considered to be one of the major factors determining the distribution of this species and affecting the annual cycle of V. parahaemolyticus in the estuarine system.

Kaneko, Tatsuo; Colwell, Rita R.



Measurement of copepod predation on nauplii using qPCR of the cytochrome oxidase I gene  

Microsoft Academic Search

A method to directly measure predation rates by older stage copepods upon copepod nauplii using species-specific primers for\\u000a the mitochondrial cytochrome oxidase subunit one gene (mtCOI) and real-time quantitative PCR (qPCR) was developed. The general\\u000a approach is to determine the mtCOI gene copy number of an individual prey organism and the copy number of the same gene in\\u000a the stomachs

Edward G. Durbin; Maria C. Casas; Tatiana A. Rynearson; David C. Smith



The effects of nickel on the reproductive ability of three different marine copepods  

Microsoft Academic Search

Lethal and sublethal toxicity of Nickel (Ni) to three marine copepods Tigriopus japonicus, Apocyclops borneoensis and Acartia pacifica was investigated. The 48-h LC50 values were 17.70, 13.05 and 2.36 mg l?1 Ni, respectively. A. pacifica was found to be the most sensitive to Ni in acute exposure tests. In order to assess sublethal effects of Ni on copepod reproduction,\\u000a the test organisms

Emadeldeen Hassan Mohammed; Guizhong Wang; Jielan Jiang



Seasonal variability in copepod ingestion and egg production on the Faroe shelf  

Microsoft Academic Search

Copepod community ingestion rates of Calanus finmarchicus, Temora longicornis, Acartia longiremis and Pseudocalanus spp., and egg production rates of C. finmarchicus and T. longicornis, were studied in relation to phytoplankton composition, abundance and biomass on the Faroe shelf during a one-year cycle.\\u000a The phytoplankton community during winter was mainly composed of small flagellates and the copepods of Pseudocalanus spp. As

Høgni Debes; Kirstin Eliasen; Eilif Gaard



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

Microsoft Academic Search

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

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



Production of a calanoid copepod, Acartia tonsa , in the Patuxent River estuary  

Microsoft Academic Search

Acartia tonsa Dana was found to be the most abundant copepod during 7 months of the year in a 10-mile segment of the Patuxent River estuary.\\u000a Densities up to 100,000 copepods per cubic meter were observed during the warmer months, and as low as 1,500 during the colder\\u000a months. The summer population was composed mainly of immature stages and the

Donald R. Heinle



New calanoid and harpacticoid copepods from beneath the Ross Ice Shelf, Antarctica  

Microsoft Academic Search

During the 1978–1979 season of the Ross Ice Shelf Project, calanoid and harpacticoid copepods were captured at the J9 site (82°22.5'S, 168°37.5'W). It is deduced that these copepods are scavengers as they were attracted to bait. At least five species were taken, three of them previously undescribed: Xanthocalanus harpagatus n.sp., Xanthocalanus sp. copepodites, Tharbyis magna n.sp., Tisbe spinulosa n. sp.,

J. M. Bradford; J. B. J. Wells



Regional-Scale Mean Copepod Concentration Indicates Relative Abundance of North Atlantic Right Whales  

Microsoft Academic Search

Management plans to reduce human-caused deaths of North Atlantic right whales Eubalaena glacialis depend, in part, on knowing when and where right whales are likely to be found. Local environmental conditions that influence movements of feeding right whales, such as ultra-dense copepod patches, are unpredictable and ephemeral. We examined the utility of using the regional-scale mean copepod concentration as an

Daniel E. Pendleton; Andrew J. Pershing; Moira W. Brown; Charles A. Mayo; Robert D. Kenney; Nicholas R. Record; Timothy V. N. Cole



Trends in copepod communities in the Navesink and Shrewsbury rivers, New Jersey: 1962–1992  

Microsoft Academic Search

The calanoid copepod community was surveyed semi-monthly, from May to July 1992, at three stations in the Navesink-Shrewsbury\\u000a rivers system, the southernmost branch of the Hudson-Raritan estuary (New York-New Jersey). The dominant species collected\\u000a during the survey wasAcartia hudsonica, followed byA. tonsa. A comparison of this survey with three earlier surveys suggests that the calanoid copepod community and relative abundance

Patricia A. Shaheen; Frank W. Steimle



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

Microsoft Academic Search

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

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



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

PubMed Central

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

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



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

NASA Astrophysics Data System (ADS)

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

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



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

NASA Astrophysics Data System (ADS)

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

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



Characteristics of the association between the marine copepod, Gastrodelphys clausii, and its fanworm host Bispira volutacornis  

NASA Astrophysics Data System (ADS)

Characteristics of the association of the marine copepod Gastrodelphys clausii with its fanworm host Bispira volutacornis were investigated from October 1997 to August 1999. Of the 982 hosts examined, 22.6% were infected, with male copepods outnumbering females. Prevalence varied between 3 and 90% during the study period and showed a seasonal pattern with a summer and late autumn/winter peak. Hosts were observed to harbour both single and multiple infections. The aggregation of parasites within the host population was overdispersed, displaying a characteristically clumped pattern. G. clausii reaches adulthood in males at ca. 800 ?m in length, with recorded total lengths extending to 1,875 ?m. Females at maturity were recorded to be ca. 1,000 ?m, with a maximum total length of 3,250 ?m recorded for an ovigerous female. Copepods were mobile within the branchial crown and showed no statistical preference for branchial crowns of different sizes. A positional pattern, however, was observed with juvenile copepods observed to occupy radioles further from the prostomium, as the branchial crown increases the number of radioles in each spiral. Contrary to this, the majority of female copepods were located attached to the radioles closest to the prostomium irrespective of crown size.

Nash, Róisín; Keegan, Brendan F.



The lunule of caligid copepods: an evolutionarily novel structure.  


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


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



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.



Accumulation of paralytic shellfish poisoning toxins in planktonic copepods during a bloom of the toxic dinoflagellate Alexandrium tamarense in Hiroshima Bay, western Japan  

Microsoft Academic Search

Concentrations of paralytic shellfish poisoning (PSP) toxins in toxic dinoflagellate cells and in marine planktonic copepods were monitored during the bloom of Alexandrium tamarense in Hiroshima Bay, western Japan. Concentration of the toxins retained by copepods was a function of the ambient toxin concentration, i.e. the product of A. tamarense cell density and cellular toxicity. The toxin concentration in copepods

Koji Hamasaki; Tomoyuki Takahashi; Shin-ichi Uye



Diel vertical migration of the marine copepod Calanopia americana . I. Twilight DVM and its relationship to the diel light cycle  

Microsoft Academic Search

Marine copepods commonly exhibit vertical movements in the water column over the diel cycle, termed diel vertical migration (DVM), with the most common pattern being an ascent in the water column to minimum depth around sunset and descent to maximum depth around sunrise. The present study characterized the DVM pattern of the pontellid copepod Calanopia americana Dahl in the Newport

J. H. Cohen; R. B. Forward Jr



Acute toxicity of crude oil water accommodated fraction on marine copepods: the relative importance of acclimatization temperature and body size.  


Recent oil spillage accidents around the world greatly increase harmful risks to marine ecology. This study evaluated the influences of petroleum water accommodated fraction (WAF) on 15 typical species of marine copepods collected from a subtropical bay in East China Sea at different seasons. Copepods showed impaired swimming ability, restlessness, loss of balance, anoxic coma, and even death when they were acutely exposed to the crude oil WAF under laboratory conditions. The LC(50) values (expressed in total petroleum hydrocarbon concentration) indicated that the tolerances of copepods to WAF decreased significantly (P < 0.05) with increased exposure duration and natural water temperatures (acclimatization temperature). The sensitivity of the copepods was species-specific (P < 0.01), and there was a significant (P < 0.05) positive correlation between the 48-h LC(50) and body size. Therefore, the small copepod species confront more survival challenges under oil contamination stress, especially in the warm months or regions. PMID:22921874

Jiang, Zhibing; Huang, Yijun; Chen, Quanzhen; Zeng, Jiangning; Xu, Xiaoqun



The effects of bis(tributyltin) oxide on the development, reproduction and sex ratio of calanoid copepod Pseudodiaptomus marinus  

NASA Astrophysics Data System (ADS)

In order to study the biological effects by bis(tributyltin) oxide (TBTO) exposure, chronic toxicity tests were conducted on the calanoid copepod Pseudodiaptomus marinus over two generations. The results indicated that nauplii were more sensitive than copepodites. F1 copepods were more vulnerable than F0 copepods and a drastic increase in mortality was observed as the TBTO concentration became higher. Exposure of copepods to 60 ng l-1 TBTO concentration reduced the fecundity and resulted in some females being infecund (in the F0 generation). The time to the first egg sac for females in the F1 generation exposed to 6 ng l-1 TBTO concentration was significantly reduced, and the fecundity of this generation was increased. The female-to-male ratio in the F1 generation exposed to 20 ng l-1 TBTO concentration was significantly reduced. These results show that the current ambient TBT concentration may influence populations of copepods in the coastal environment.

Huang, Y.; Zhu, L.; Liu, G.



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


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



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


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

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



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


All representatives of the subfamily Agonostominae of grey mullets in the collections of The Natural History Museum in London were examined for parasitic copepods. Agonostomus monticola, Joturus pichardi, Aldrichetta forsteri and Cestraeus goldiei were all infected by copepods. Three new species of Acusicola and two new species of Ergasilus were found: E. parabahiensis n. sp. on A. monticola from Guyana and E. acusicestraeus n. sp. on C. goldiei from Papua New Guinea. Acusicola spinuloderma n. sp. was found on A. monticola and J. pichardi collected from different localities in Central America, A. mazatlanesis n. sp. on the same host from west Mexico (Mazatlan) and A. joturicola n. sp. on J. pichardi from Panama. Descriptions of the five new species and a redescription of E. australiensis Roubal, from Aldrichetta forsteri, are presented. The host-parasite relationships and geographical distributions of hosts and their parasitic copepods are analysed. PMID:10613535

El-Rashidy, H; Boxshall, G A



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.



Integumental ultrastructure and color patterns in the iridescent copepods of the family Sapphirinidae (Copepoda: Poecilostomatoida)  

Microsoft Academic Search

The ultrastructure of the integument of the sapphirinid copepods was studied by scanning and transmission electron microscopy. Samples were collected between 1991 and 1993 by plankton-net tows from the subtropical and tropical waters of the North Pacific. In all the seven species examined of Sapphirina and Copilia, a structure with multilayered platelets was found in the epidermal cells of the

J. Chae; Shuhei Nishida



Effects of diet on release of dissolved organic and inorganic nutrients by the copepod Acartia tonsa  

Microsoft Academic Search

Acartia tonsa copepods are not limited to herbivory and can derive up to half their daily ration from predation on heterotrophic ciliates and dinoflagellates. The effects of an omnivorous diet on nutrient regeneration, however, remain unknown. In this study, we fed A. tonsa an exclusively carnivorous diet of either (1a) heterotrophic dinoflagellate Oxyrrhis marina or (1b) Gyrodinium dom- inans, (2)

Grace K. Saba; Deborah K. Steinberg; Deborah A. Bronk



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




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...


Outbreeding Depression as a Cost of Dispersal in the Harpacticoid Copepod, Tigriopus caZifomicus  

Microsoft Academic Search

The costs of dispersing can be evaluated in terms of genetic expenses. These costs are associated with outbreeding depression. In the supralittoral zone of the rocky shore, both outbreeding depression and inbreeding depression may be important in determining whether an organism should disperse. These genetic costs were in- vestigated in the harpacticoid copepod, Tigriopus califor- nicus, which inhabits supralittoral pools.




Cascading predation effects of Daphnia and copepods on microbial food web components  

Microsoft Academic Search

SUMMARY 1. We performed a mesocosm experiment to investigate the structuring and cascading effects of two predominant crustacean mesozooplankton groups on microbial food web components. The natural summer plankton community of a mesotrophic lake was exposed to density gradients of Daphnia and copepods. Regression analysis was used to reveal top- down impacts of mesozooplankton on protists and bacteria after days




Comparison between five coexisting species of marine copepods feeding on naturally occurring particulate matter  

Microsoft Academic Search

Grazing by five species of copepods on naturally occurring particles has been investigated over a 1-yr period. The consumption of particles by each species was associated with changes in both total concentration and composition of suspended particulate material. All the cope- pods reacted similarly and simultaneously to the changes of the particle size spectrum by shifting their grazing pressure from

S. A. Poulet



Ecological and evolutionary significance of resting eggs in marine copepods: past, present, and future studies  

Microsoft Academic Search

The occurrence of a resting egg phase in the life cycle of marine and freshwater planktonic copepods is well documented and receiving increasing attention by investigators. The species generally occur in coastal marine waters, freshwater ponds and lakes in areas that undergo strong seasonal fluctuations, though examples have been reported for tropical and sub-tropical areas not subject to such extreme

Nancy H. Marcus



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

Microsoft Academic Search

There is an increasing body of evidence to support the significant role of invertebrates in assessing impacts of environmental contaminants on marine ecosystems. Therefore, in recent years massive efforts have been directed to identify viable and ecologically relevant invertebrate toxicity testing models. Tigriopus, a harpacticoid copepod has a number of promising characteristics which make it a candidate worth consideration in

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



Behavioural responses of two cladocerans and two copepods exposed to fish kairomones  

Microsoft Academic Search

In natural predator–prey interactions, chemical communication is one of the most advantageous strategies for prey organisms because they can anticipate possible harm by means of phenotypic changes. This study compares the changes in the behaviour of four freshwater zooplankton species in the presence and absence of infochemicals from the same predator. The studied organisms are two copepods and two cladocerans

M. F. Gutierrez; A. M. Gagneten; J. C. Paggi



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

Microsoft Academic Search

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

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



Co-occurrence of copepods and dissolved free amino acids in shelf sea waters  

Microsoft Academic Search

The vertical distribution of chlorophylla, copepods, dissolved free amino acid concentration and the fixation of14C by phytoplankton were monitored in the springs of 1983, 1987 and 1988 in the Ushant front region, shelf edge of the Celtic Sea and central Irish Sea, respectively. In each area, two stations characterized by mixed and stratified water conditions were compared. Vertical distributions of

S. A. Poulet; R. Williams; D. V. P. Conway; C. Videau



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 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.

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



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



Seasonal study of planktonic copepods and their benthic resting eggs in northern California coastal waters  

Microsoft Academic Search

Few investigations have examined the occurrence of zooplankton resting eggs in the sea bed of waters deeper than 20 m. In this study the distribution and abundance of planktonic copepods and their benthic resting eggs in coastal waters off northern California, U.S.A., were determined and related to environmental parameters (temperature, salinity, depth, and sediment grain size). Sediment cores, net tows,

N. H. Marcus



Copepods in turbid shallow soda lakes accumulate unexpected high levels of carotenoids.  


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



Diet influence on egg production of the copepod Acartia tonsa (Dana, 1896).  


Egg production in the copepod Acartia tonsa was evaluated using different densities of the microalgae Thalassiosira weissflogii, Chaetoceros muelleri and Isochrysis galbana. Male and female were kept under controlled conditions (salinity 30, 20 degrees C, photoperiod 12L:12D), acclimated to the experimental conditions and left over a period of 24 h to allow copulation. Algal densities tested were equivalent in biovolume and corresponded to 0, 2.5, 5, 10, 20, 40 and 60.10(3) cells.mL-1 of T weissflogii. Ten acclimated female were separated, transferred to glass bottles and exposed for further 24 h to the corresponding experimental medium. After this period, the eggs were fixed and counted. Copepod egg production reached a threshold value when T weissflogii, C. muelleri and I. galbana were supplied at 10.10(3), 140.10(3) and 640.10(3) cells.mL-1, respectively. Mean egg production corresponded to 28.0 +/- 0.5, 20.1 +/- 1.0 and 22.0 +/- 3.5 eggs.female-1 .day-1, respectively. Copepods fed T weissflogii showed the highest mean egg production while those fed I. galbana reached a maximum egg production when the algae were supplied at a density two- to fourfold higher, considering the biovolume of T weissflogii and C. muelleri. These differences are explained considering the different sizes of the microalgae used to feed the copepods. PMID:20563414

Teixeira, Priscila F; Kaminski, Sonia M; Avila, Tatiana R; Cardozo, Alessandro P; Bersano, José G F; Bianchini, Adalto



Genetic differentiation and reproductive incompatibility among Baja California populations of the copepod Tigriopus californicus  

Microsoft Academic Search

Populations of the harpacticoid copepod Tigriopus californicus were sampled from five sites from San Diego, California, to Playa Altamira, Baja California, Mexico. Allozyme analyses revealed that all the study populations are sharply differentiated genetically. At the extreme, two populations, Punta Baja and Playa Altamira, have no alleles in common at the seven allozyme loci studied. All pairwise interpopulation crosses successfully

H. H. Ganz; R. S. Burton



Optimal foraging theory as a predictor of chemically mediated food selection by suspension-feeding copepods  

Microsoft Academic Search

Chemically mediated food selection was studied by offering copepods pairs of particles which differed in nutritional quality or size. Eudiaptomus spp. fed in varying concentrations of algae and polystyrene spheres, high-quality algae of different sizes, toxic and nontoxic algae, digestible and digestion-resistant algae, live and dead algae, and dead algae with and without attached bacteria. Experiments with polystyrene spheres showed

William R. DeMottl




Microsoft Academic Search

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



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




Microsoft Academic Search

In northern Vietnam, copepods of the genus Mesocyclops were used for biological control of Aedes aegypti, the principal vector of dengue viruses, by inoculation into wells, large cement tanks, ceramic jars, and other domestic containers that served as Ae. aegypti breeding sites. The use of Mesocyclops was complemented by com- munity participation with respect to recycling to eliminate unused and



Mechanism of acute silver toxicity in the euryhaline copepod Acartia tonsa.  


Acute silver effects on whole-body ion regulation and Na(+),K(+)-ATPase activity were evaluated in the euryhaline copepod Acartia tonsa. Experiments were run at 20 degrees C, three different salinities (5, 15 and 30 ppt), in either the absence or the presence of food (diatom Thalassiosira weissflogii; 2 x 10(4)cells/mL). Standard static-renewal procedures were used. Copepods were acutely (48 h) exposed to silver (AgNO(3)) concentrations equivalent to the 48-h EC10 (dissolved Ag=3, 49, and 94 microg/L), 48-h EC30 (dissolved Ag=5, 71, and 125 microg/L) or 48-h EC50 (dissolved Ag=7, 83, and 173 microg/L) values in the absence of food or to the 48-h EC50 (dissolved Ag=35, 90, and 178 microg/L) values in the presence of food. These values were previously determined under the same experimental conditions at salinities 5, 15 and 30 ppt, respectively. Endpoints analyzed were whole-body ion concentrations (Na(+), Cl(-), and Mg(2+)) and Na(+),K(+)-ATPase activity. In starved copepods, lower whole-body Na(+) and Mg(2+) concentrations were observed in salinities 5 and 30 ppt, respectively. Also a higher whole-body Na(+),K(+)-ATPase activity was observed in all salinities tested. Data from fed copepods indicate that all these salinity effects were completely associated with starvation. Silver exposure induced a decrease in the whole-body Mg(2+) concentration in starved copepods in salinities 5 and 30 ppt and a Na(+),K(+)-ATPase inhibition in both starved and fed copepods in all salinities tested. Thus, food addition in the experimental media completely protected against silver effects on Mg(2+) concentration, but not against those on Na(+),K(+)-ATPase activity. In starved copepods, enzyme inhibition was dependent on silver concentration and a relationship between this parameter and mortality was observed in all salinities tested. Therefore, Na(+),K(+)-ATPase molecules seem to be a key site for acute silver toxicity in marine invertebrates, as reported for freshwater fish and crustaceans. PMID:17374407

Pedroso, Mariana S; Pinho, Grasiela L L; Rodrigues, Sandra C; Bianchini, Adalto



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


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



Dramatic change in the copepod community in Sevastopol Bay (Black Sea) during two decades (1976–1996)  

Microsoft Academic Search

The seasonal and inter-annual fluctuation of species composition and abundance of copepods in Sevastopol Bay (Black Sea) are\\u000a presented for the years 1976, 1979–80, 1989–90, 1995–96. The copepod community of the Sevastopol Bay shifted to an other state\\u000a from the beginning of the seventies to 1996. The main change in the species composition occurred in 1989–1996, when the average\\u000a annual

A. D. Gubanova; I. Yu. Prusova; U. Niermann; N. V. Shadrin; I. G. Polikarpov



Effects of food nitrogen content and concentration on the forms of nitrogen excreted by the calanoid copepod, Acartia tonsa  

Microsoft Academic Search

Nitrogen excreted as ammonium, urea, and dissolved primary amines (DPA), and nitrogen ingested by the planktonic calanoid copepod, Acartia tonsa, were measured while fed 4 foods with different N\\/C ratios in high (500 ?g C l?1) and low (50 ?g C l?1) concentrations. Adult copepods were fed the ciliate, Uronema marinum (N\\/C=0.26), the diatom, Thalassiosira weissflogii, in log-phase growth (N\\/C=0.20), and in

Carolyn A. Miller; Michael R. Roman



Occurence of intersexuality in a laboratory culture of the copepod Eurytemora affinis from the Seine estuary (France)  

Microsoft Academic Search

We show in this study that intersexuality can occur in the estuarine copepod Eurytemora affinis, and we reported the presence of three intersexual copepod individuals from a laboratory culture of this species from the\\u000a Seine estuary conducted at low temperature (7°C). These individuals presented both female and male characteristics. The prosome\\u000a size and antennules of intersex individuals were similar to

Anissa Souissi; Sami Souissi; David Devreker; Jiang-Shiou Hwang



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



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.



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

NASA Astrophysics Data System (ADS)

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

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



Microcystin-LR toxicity on dominant copepods Eurytemora affinis and Pseudodiaptomus forbesi of the upper San Francisco Estuary.  


This study investigates the toxicity and post-exposure effects of dissolved microcystin (MC-LR) on the dominant copepods of the upper San Francisco Estuary (SFE), where blooms of the toxic cyanobacteria Microcystis aeruginosa coincide with record low levels in the abundance of pelagic organisms including phytoplankton, zooplankton, and fish. The potential negative impact of Microcystis on the copepods Eurytemora affinis and Pseudodiaptomus forbesi has raised concern for further depletion of high quality fish food. Response of copepods to MC-LR (MC) was determined using a 48-h standard static renewal method for acute toxicity testing. Following exposure, a life table test was performed to quantify any post-exposure impacts on survival and reproduction. The 48-h LC-50 and LC-10 values for MC were 1.55 and 0.14 mg/L for E. affinis; and 0.52 and 0.21 mg/L for P. forbesi. Copepod populations recovered once dissolved MC was removed and cultures returned to optimal conditions, suggesting no post-exposure effects of MC on copepod populations. Dissolved microcystin above 0.14 mg/L proved likely to have chronic effects on the survival of copepods in the SFE. Since such high concentrations are unlikely, toxicity from dissolved microcystin is not a direct threat to zooplankton of the SFE, and other mechanisms such as dietary exposure to Microcystis constitute a more severe risk. PMID:19539351

Ger, Kemal A; Teh, Swee J; Goldman, Charles R



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.



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


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

McKinnon, Christian; Drouin, Guy



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


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

Kiørboe, Thomas



Are monoalgal diets inferior to plurialgal diets to maximize cultivation of the calanoid copepod Temora stylifera ?  

Microsoft Academic Search

Temora stylifera adult copepods were fed with four different monoalgal diets and six combinations of the same cultures for 15 days. Fecundity,\\u000a hatching success, number of cannibalized embryos, fecal pellet production, adult mortality and naupliar recruitment were compared,\\u000a in order to find the best diet for this species. Phytoplankton species tested were Prorocentrum minimum (PRO); Isochrysis galbana (ISO); Tetraselmis suecica (TETRA)

I. Buttino; A. Ianora; S. Buono; V. Vitello; G. Sansone; A. Miralto



Does cyanobacterial toxin accumulate in mysid shrimps and fish via copepods?  

Microsoft Academic Search

It has been suggested that pelagic planktivores may receive cyanobacterial toxins indirectly, i.e., by preying on organisms that have ingested cyanobacteria. We tested this hypothesis in laboratory conditions by providing mysid shrimps, Mysis relicta, and three-spined sticklebacks, Gasterosteus aculeatus, with cyanobacteria-fed copepods. The aim of the study was to observe the potential transfer and accumulation of the toxin nodularin, produced

Jonna Engström-Öst; Maiju Lehtiniemi; Sandra Green; Betina Kozlowsky-Suzuki; Markku Viitasalo



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

Microsoft Academic Search

The goal of this paper is to illustrate how in juvenile and adult subtropical marine planktonic copepods various structures or morphological features function in concert to detect prey and predators. Without motion by either food (e.g. flagellate, ciliate) or feeder (e.g. feeding current) or both (e.g. Acartia spp. and ciliate) few feeding activities will occur. Through motion a food particle

G.-A. Paffenhöfer



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

SciTech Connect

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

Paffenhoefer, G.A.; Lewis, K.D. [Skidaway Inst. of Oceanography, Savannah, GA (United States); Bundy, M.H. [Skidaway Inst. of Oceanography, Savannah, GA (United States)]|[Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE); Metz, C. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE)



Astaxanthin, canthaxanthin and astaxanthin esters in the copepod Acartia bif ilosa (Copepoda, Calanoida) during ontogenetic development  

Microsoft Academic Search

The contents of astaxanthin, canthaxanthin and astaxanthin esters were studied in natural populations of the copepod Acartia bifilosa from the Pomeranian Bay and Gulf of Gda?sk in the southern Baltic Sea. Samples dominated by any one of three developmental groups: (1) nauplii, (2) copepodids I-III and (3) copepodids IV-V and adults of Acartia bifilosa were analysed by means of high

Ewa Styczy?ska-Jurewicz


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

NASA Astrophysics Data System (ADS)

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

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



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

Microsoft Academic Search

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

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



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

Microsoft Academic Search

During the Polarstern-cruise ARK IV\\/2 June 1987, in the Fram Strait, dinophytes parasitizing copepod eggs were observed. In\\u000a the laboratory on board, vegetative reproduction was documented and re-infection ofCalanus glacialis andC. hyperboreus eggs was experimentally established. During food uptake, a primary cyst produces successively several secondary cysts, all\\u000a separating immediately after formation from the primary cyst. In every one of

Malte Elbrächter



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

Microsoft Academic Search

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

Haruko Kurihara; Shinji Shimode; Yoshihisa Shirayama



Functional responses of copepod nauplii using a high efficiency gut fluorescence technique  

Microsoft Academic Search

To investigate copepod nauplii ingestion rates on phytoplankton, we have adapted the traditional gut fluorescence technique\\u000a as it can be used with lower gut pigment concentrations. With the improved technique, laboratory experiments were performed\\u000a to estimate functional responses for nauplii of Calanus helgolandicus and Centropages typicus. Nauplii were raised from eggs to copepodites and the experiments were performed with stages

Eva López; Ricardo Anadón; Roger P. Harris



Lipid and fatty acid content in cultivated live feed organisms compared to marine copepods  

Microsoft Academic Search

The total lipid content in Artemia franciscana (21–23% ofdry weight (DW)) when enriched with either Super Selco or DHA Selco wastwice as high as in the adult copepods Temora longicornis and Eurytemora sp.(9–11% of DW). In Brachionus plicatilis the total lipid contentwas 11 and 6.6% for cultures growing at high and low growth rate,0.12 d-1 and 0.38 d-1, respectively. In

Jan Ove Evjemo; Yngvar Olsen



Studies on the population dynamics and production of inshore marine copepods  

Microsoft Academic Search

It is indeed my great honor to receive the Okada Prize (1983) for my studies on the population dynamics and production of\\u000a inshore marine copepods. This article summarizes the lecture I gave under the above title.\\u000a \\u000a It has long been postulated that there is some mechanism whereby a species can repopulate after its disappearance from the\\u000a plankton, since the appearance

Shin-ichi Uye




Microsoft Academic Search

We demonstrate significant genetically based differentiation in embryonic duration (h), egg size (Mm3),and newborn survival (number\\/h) in the harpacticoid copepod, Scottolana canadensis (Crustacea),taken from a broad range of latitudes (°N)and reared in the laboratory for several generations under the same conditions. Egg development times of the northern-derived (ME) individuals were significantly longer at all test temperatures, and thus did not




Use of plant products and copepods for control of the dengue vector, Aedes aegypti  

Microsoft Academic Search

The efficacy of plant extracts (neem tree, Azadirachta indica A. Juss.; Meliaceae) and copepods [Mesocyclops aspericornis (Daday)] for the control of the dengue vector Aedes aegypti L. was tested in the laboratory. Neem Seed Kernel Extract (NSKE) at 25, 50, 100, 200 and 400 ppm caused significant mortality\\u000a of Ae. aegypti larvae. Lethal concentrations (LC50 and LC90) were worked out. The

K. Murugan; Jiang-Shiou Hwang; K. Kovendan; K. Prasanna Kumar; C. Vasugi; A. Naresh Kumar



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


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

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



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



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

SciTech Connect

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

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



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


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



Bacterial colonization on fecal pellets of harpacticoid copepods and on their diatom food.  


Fecal pellets make up a significant fraction of the global flux of organic matter in oceans, and the associated bacterial communities in particular are a potential food source for marine organisms. However, these communities remain largely unknown. In the present study, the bacterial communities on fecal pellets of the benthic copepod Paramphiascella fulvofasciata feeding on the diatoms Navicula phyllepta and Seminavis robusta were analyzed. The aim of this study was to characterize the bacterial communities associated with the diatoms and the fecal pellets by means of DGGE profiling. Furthermore, isolated bacteria were characterized by means of partial 16S rRNA gene sequencing. The composition of the bacterial microflora on fecal pellets was studied in terms of the effect of the original food source, the age of the fecal pellets and the copepod's identity. Alphaproteobacteria, Flavobacteria, and Bacilli were found on the fecal pellets; whereas on diatoms, exclusively Gammaproteobacteria were identified. Especially after eating N. phyllepta, there was an important increase in bacterial diversity, although the diatom N. phyllepta harbored a less diverse bacterial community than S. robusta. Our data suggest that the additional bacteria originate from the copepod's digestive tract and largely depends on the initial food source. PMID:20440489

De Troch, Marleen; Cnudde, Clio; Willems, Anne; Moens, Tom; Vanreusel, Ann



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


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

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



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


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



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.

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



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.



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.

Hassett, R. Patrick; Crockett, Elizabeth L.



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.

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



Differential gene expression profile of the calanoid copepod, Pseudodiaptomus annandalei, in response to nickel exposure.  


To better understand the underlying mechanisms of reactions of copepods exposed to elevated level of nickel, the suppression subtractive hybridization (SSH) was used to elucidate the response of the copepod Pseudodiaptomus annandalei to nickel exposure at the gene level. P. annandale is one of a few copepod species that can be cultured relatively easy under laboratory condition, and it is considered to be a potential model species for toxicity study. In the present study, P. annandalei were exposed to nickel at a concentration of 8.86 mgL(-1) for 24h, after which the RNA was prepared for SSH using unexposed P. annandalei as drivers. A total of 474 clones on the middle scale in the SSH library were sequenced. Among these genes, 129 potential functional genes were recognized based on the BLAST searches in NCBI and Uniprot databases. These genes were then categorized into nine groups in association with different biological processes using AmiGO against the Gene Ontology database. Of the 129 genes, 127 translatable DNA sequences were predicted to be proteins, and the putative amino acid sequences were searched for conserved domains (CD) and proteins using the CD-Search service and BLASTp. Among 129 genes, 119 (92.2%) were annotated to be involved in different biological processes, while 10 genes (7.8%) were classified as an unknown-function gene group. To further confirm the up-regulation of differentially expressed genes, the quantitative real time PCR were performed to test eight randomly selected genes, in which five of them, i.e. ?-tubulin, ribosomal protein L13, ferritin, separase and Myohemerythrin-1, exhibited clear up-regulation after nickel exposure. In addition, MnSOD was further studied for the differential expression pattern after nickel exposure and the results showed that MnSOD had a time- and dose-dependent expression pattern in the copepod after nickel exposure. To the best of our knowledge, this is the first attempt to investigate the toxicity effects of nickel on a copepod at molecular level. PMID:23164661

Jiang, Jie-Lan; Wang, Gui-Zhong; Mao, Ming-Guang; Wang, Ke-Jian; Li, Shao-Jing; Zeng, Chao-Shu



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


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



Effect of grazing-mediated dimethyl sulfide (DMS) production on the swimming behavior of the copepod Calanus helgolandicus.  


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

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



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

PubMed Central

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

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



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.

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



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


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



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

Microsoft Academic Search

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

Barbara Niehoff



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

Microsoft Academic Search

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

Sean P. Colin; Hans G. Dam



Effects of prey concentration, prey size, predator life stage, predator starvation, and season on predation rates of the carnivorous copepod Euchaeta elongata  

Microsoft Academic Search

Adult females of the large carnivorous copepod Euchaeta elongata Esterly were collected from 1977 to 1980 in Port Susan, Washington, USA. Predation rates of the adult females increased with increasing prey abundance when fed the following 4 sizes of copepods: adult females of Calanus pacificus (average prosome length [PL] of 2 650 µm), adults of Aetideus divergens (PL of 1

J. Yen



Infestation of the blue mussel Mytilus galloprovincialis by the copepod Pseudomyicola spinosus and its relation to size, density, and condition index of the host  

Microsoft Academic Search

The copepod Pseudomyicola spinosus infests marine mussels and other commercial bivalve species. There is a lack of information on the infestation process and on its relationship to size, density, and health of the host. To obtain this information, an infestation study of the copepod in Mytilus galloprovincialis in field conditions was carried out. Results showed that the intensity of infestation

José Angel Olivas-Valdez; Jorge Cáceres-Mart??nez



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.



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


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

Volz, David C; Chandler, G Thomas



Zooplankton communities of the Arctic’s Canada Basin: the contribution by smaller taxa  

Microsoft Academic Search

Zooplankton was sampled at ten stations in the Canada Basin during August 2002 using both 53- and 236-?m mesh nets to examine the contribution by smaller and less studied species. Copepod nauplii, the copepods Oithona similis, Oncaea borealis and Microcalanus pygmaeus, and the larvacean Fritillaria borealis typica dominated the upper 100 m of the water column numerically, while biomass was dominated

R. R. Hopcroft; C. Clarke; R. J. Nelson; K. A. Raskoff



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


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

Breitholtz, Magnus; Wollenberger, Leah; Dinan, Laurence



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

NASA Astrophysics Data System (ADS)

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

Kim, Il-Hoi; Moon, Seong Yong



Copepod behavior in thin layers of attractive and deterrent chemical cues  

NASA Astrophysics Data System (ADS)

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

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



Optimal salinity for dominant copepods in the East China Sea, determined using a yield density model  

NASA Astrophysics Data System (ADS)

From 1997 to 2000, four field surveys were conducted in the East China Sea (ECS) (23°30'-33°00'N, 118°30'-128°00'E). A field data yield density model was used to determine the optimal salinities for 19 dominant copepod species to establish the relationship between surface salinities and abundance of those species. In addition, ecological groups of the copepods were classified based on optimal salinity and geographical distribution. The results indicate that the yield density model is suitable for determining the relationship between salinity and abundance. Cosmocalanus darwini, Euchaeta rimana, Pleuromamma gracilis, Rhincalanus cornutus, Scolecithrix danae and Pareucalanus attenuatus were determined as oceanic species, with optimal salinities of >34.0. They were stenohaline and mainly distributed in waters influenced by the Kuroshio or Taiwan warm current. Temora discaudata, T. stylifera and Canthocalanus pauper were nearshore species with optimal salinities of <33.0 and most abundant in coastal waters. The remaining 10 species, including Undinula vulgaris and Subeucalanus subcrassus, were offshore species, with optimal salinity ranging from 33.0-34.0. They were widely distributed in nearshore, offshore and oceanic waters but mainly in the mixed water of the ECS.

Xu, Zhaoli; Gao, Qian



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


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

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



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


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

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



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


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



Feeding behavior of large calanoid copepods Neocalanus cristatus and N. plumchrus from the subarctic Pacific Ocean  

NASA Astrophysics Data System (ADS)

Oceanic waters of the subarctic Pacific exhibit a special ecological feature, a virtually seasonally invariant standing stock of phytoplankton (measured as chlorophyll a), that seems to reflect a balance, at least during spring and summer, between phytoplankton growth and zooplankton grazing. The grazers presumed to be responsible for the balance are the calanoid copepods Neocalanus cristatus and N. plumchrus. Shipboard grazing experiments, utilizing both natural suspended particulate material and cultured phytoplankton as food for the copepods, showed that both species have at least three attributes of feeding behavior required to maintain steady standing stock of phytoplankton. That is, the Neocalanus species can feed at the low concentrations of phytoplankton that prevail in the open subarctic Pacific, they feed at similar rates on a broad range of particlessizes including the predominant particles, and they respond to small increases in phytoplankton concentration by proportionately larger increases in their feeding rate. Although both species of Neocalanus attain larger body sizes than co-occurring Calanus pacificus and Pseudocalanus sp., they have morphological specializations that seem to account for their unexpected ability to feed on very dilute suspensions of small phytoplankton cells. It appears that the perpetually low phytoplankton concentrations in the open subarctic Pacific do not permit maximum feeding effort by the species of Neocalanus.

Frost, B. W.; Landry, M. R.; Hassett, R. P.




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...


Life cycle plasticity and differential growth and development in marine and lacustrine populations of an Antarctic copepod  

Microsoft Academic Search

We examined life cycle plasticity in two populations of the copepod Paralabidocera antarctica, one of which inhabits the coastal sea ice belt of Antarctica and the other of which has been isolated in a nearby saline lake for several thousand generations. Similarities in the life cycles of the two populations included long overwintering phases (.5 months) by late-stage nauplii, rapid

K. M. Swadling; A. D. McKinnon; G. De'ath; J. A. E. Gibson



Modification of the feeding behavior of marine copepods by sub-lethal concentrations of water-accommodated fuel oil  

Microsoft Academic Search

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 µg l-1, but their feeding behavior was altered both quantitatively and qualitatively at a concentration of 250 µg l-1. Three types of response

M. S. Berman; D. R. Heinle



Seasonal and Spatial Patterns of Deeply Buried Calanoid Copepods on the Amazon Shelf: Evidence for Periodic Erosional/Depositional Cycles  

NASA Astrophysics Data System (ADS)

Seasonal sampling of Amazon shelf deposits revealed that calanoid copepods as well as other pelagic zooplankton were often buried along with benthic infauna throughout the upper ˜25 cm of the sea-bed. During February through March, the period of rising to peak riverine discharge and maximum trade wind stress, shelf-wide maxima occur in numbers and depth of burial. Buried copepods were present in all stations with abundances reaching 5168 copepods m -3in the 10-25-cm depth interval off the river mouth in 18 m of water (Station RMT-2). The intact nature of the buried copepods and presence of phytoplankton within the digestive tracts of many, supports the notion that burial was sudden and rapid (˜hours). In contrast, from August to October, the period of falling to low riverine discharge and minimum wind stress, burial of zooplankters was restricted to stations along a southern transect (ST) and at the innermost river mouth station (RMT-1). Burrowing macroinfauna, meiofauna and bacterial inventories increase dramatically at all shelf stations during the time of minimum zooplankton burial. Successful recolonization by benthos and lack of entrainment of water-column organisms show that the bottom is most stable during seasons of falling to low river flow. Sedimentologic and chemical, as well as biological, evidence indicates rapid turnover of ˜20-30 cm of the sea-bed during rising- and peak-flow periods when the sea-bed is most unstable.

Aller, Josephine Y.; Todorov, Julia R.



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



Interannual variability in a predator-prey interaction: climate, chaetognaths, and copepods in the southeastern Bering Sea  

Microsoft Academic Search

The interaction of the chaetognath Sagitta elegans with the copepod community of the southeast Bering Sea middle shelf was examined in relation to environmental conditions during 1995-1999. Predation impact was estimated for 2 years, 1995 and 1997, using gut content analysis, experimentally derived digestion time (DT) and abundances of chaetognaths and prey. Pseudoca- lanus concentrations correlated with water temperature and

C. T. Baier; M. TERAZAKI



RNA:DNA ratios of calanoid copepods from the epipelagic through abyssopelagic zones of the North Pacific Ocean  

Microsoft Academic Search

As indices of protein synthetic activity, RNA:DNA ratios were determined for >80 cope- pod species caught from the epipelagic (0 to 500 m), mesopelagic (500 to 1000 m), upper bathypelagic (1000 to 2000 m), lower bathypelagic (2000 to 3000 m) and abyssopelagic (3000 to 5000 m) zones of the North Pacific Ocean. The copepods from the epipelagic zone exhibited higher

Tsutomu Ikeda; Fumikazu Sano; Atsushi Yamaguchi; Takashi Matsuishi



The first records of two neustonic calanoid copepods, pontella securifer and p. sinica (calanoida, pontellidae) in the south sea, korea  

NASA Astrophysics Data System (ADS)

The neustonic calanoid copepods Pontella securifer Brady, 1883 and P. sinica Chen and Zhang, 1965 are first recorded in Korea. These species occur in high temperatures over 23 °C and in a range of salinity from 26.6 to 31.2 psu. We provide full descriptions of the two species and discuss their zoogeography.

Jeong, Hyeon Gyeong; Suh, Hae-Lip; Yoon, Yang Ho; Choi, Im Ho; Soh, Ho Young



Studies of the biology of the West Indian copepod Ophiopsyllus reductus (Siphonostomatoida: Cancerillidae) parasitic upon the brittlestar Ophiocomella ophiactoides  

Microsoft Academic Search

The siphonostome copepod Ophiopsyllus found on the brittlestar Ophiocomella ophiactoides at Discovery Bay, Jamaica damages the host in such a way as strongly to suggest that it is feeding on the surface tissues. This supposition is supported by the structure of the mouth parts. Although reported from another brittlestar elsewhere, O. reductus is apparently specific to O. ophiactoides at Jamaica.

R. H. Emson; P. V. Mladenov; I. C. Wilkie



How coastal upwelling influences spatial patterns of size-structured diversity of copepods off central-southern Chile (summer 2009)  

Microsoft Academic Search

This study assessed the structure of the copepod community in the upper 200m of the coastal upwelling region off central-southern Chile in late summer 2009. Vertically stratified zooplankton samples and hydrographic variables were obtained from 42 stations over the continental shelf and oceanic areas. The survey took place during active upwelling, reflected by a cold upwelling plume extending out to

Pamela Hidalgo; Ruben Escribano; Marcelo Fuentes; Erika Jorquera; Odette Vergara



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...


Effects of mesoscale phytoplankton variability on the copepods Neocalanus flemingeri and N. plumchrus in the coastal Gulf of Alaska  

NASA Astrophysics Data System (ADS)

The copepods Neocalanus flemingeri and N. plumchrus are major components of the mesozooplankton on the shelf of the Gulf of Alaska, where they feed, grow and develop during April-June, the period encompassing the spring phytoplankton bloom. Satellite imagery indicates high mesoscale variability in phytoplankton concentration during this time. Because copepod ingestion is related to food concentration, we hypothesized that phytoplankton ingestion by N. flemingeri and N. plumchrus would vary in response to mesoscale variability of phytoplankton. We proposed that copepods on the inner shelf, where the phytoplankton bloom is most pronounced, would be larger and have more lipid stores than animals collected from the outer shelf, where phytoplankton concentrations are typically low. Shipboard feeding experiments with both copepods were done in spring of 2001 and 2003 using natural water as food medium. Chlorophyll concentration ranged widely, between 0.32 and 11.44 ?g l -1 and ingestion rates varied accordingly, between 6.0 and 627.0 ng chl cop -1 d -1. At chlorophyll concentrations<0.50 ?g l -1, ingestion is always low, <40 ng cop -1 d -1. Intermediate ingestion rates were observed at chlorophyll concentrations between 0.5 and 1.5 ?g l -1, and maximum rates at chlorophyll concentrations>1.5 ?g l -1. Application of these feeding rates to the phytoplankton distribution on the shelf allowed locations and time periods of low, intermediate and high daily feeding to be calculated for 2001 and 2003. A detailed cross-shelf survey of body size and lipid store in these copepods, however, indicated they were indistinguishable regardless of collection site. Although the daily ingestion of phytoplankton by N. flemingeri and N. plumchrus varied widely because of mesoscale variability in phytoplankton, these daily differences did not result in differences in final body size or lipid storage of these copepods. These copepods efficiently dealt with small and mesoscale variations in their food environment such that mesoscale structure in phytoplankton did not affect their final body size.

Dagg, M. J.; Liu, H.; Thomas, A. C.



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


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

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



In situ predatory behavior of Mysis relicta in Lake Michigan  

Microsoft Academic Search

Selectivity coefficients (W') and predation rates on Lake Michigan zooplankton were determined forMysis relicta during spring through fall using anin situ method. W' values indicated the following ranked order of prey preference: Cladocera > copepod copepodites and copepod nauplii > adult diaptomids and cyclopoids. With few exceptions, W' values for different prey categories remained fairly constant despite greatly changing relative

J. A. Bowers; H. A. Vanderploeg



Ontogenic changes of amino acid composition in planktonic crustacean species  

Microsoft Academic Search

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

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



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


The marine harpacticoid copepods Tigriopus brevicornis were collected along the French Atlantic Coast (Loire Atlantique) and subsequently exposed to different lethal and sublethal concentrations of various metals (copper, zinc, nickel, cadmium, silver and mercury) for varying lengths of time. Ultrastructural investigations of control and experimentally exposed copepods were performed to investigate the intracellular localization of metals using transmission electronic microscopy (TEM). Copepod digestive epithelium cells as well as the cuticular integument were found to be the major metal storage tissues. Different types of metal-containing granules were found in both metal-exposed copepods and the controls: (1) within lysosomes, (2) in intracellular calcospherites and (3) in extracellular tiny granules. The elemental composition of the granules was determined on ultrathin sections by means of energy dispersive X-ray spectroscopy (EDS). The results were interpreted by considering previous data in order to understand how Tigriopus brevicornis copes with the presence of metals in its environment. PMID:17629789

Barka, Sabria



Some lower food web organisms in the nutrition of marine harpacticoid copepods: an experimental study  

NASA Astrophysics Data System (ADS)

Some lower food web organisms from the marine littoral environment were studied as food for harpacticoid copepods. In laboratory experiments, it could be shown that, among the ciliates, the slow-moving Uronema sp. was taken up while the fast-moving Euplotes sp. was not. Asterionella glacialis, a pennate diatom with spiny projections, was unsuitable as food. The centric diatom Skeletonema costatum was ingested by all harpacticoid species tested, including Tisbe holothuriae, Paramphiascella vararensis, Amphiascoides debilis and Dactylopodia vulgaris. All are epibenthic and phytal species occurring in the shallow waters of Helgoland (North Sea). The amount of ciliate and algal carbon taken up was less than that provided by bacteria under laboratory conditions. However, some diatom food may be essential for the development of D. vulgaris.

Rieper, Marianna



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

NASA Astrophysics Data System (ADS)

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

Elbrächter, Malte



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.



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


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



Roles of resource and partner availability in sex determination in a parasitic copepod  

PubMed Central

Because sexuality plays an essential role in gene transmission and consequently in the evolution of species, investment into male or female function constitutes a key factor in the reproductive success of individuals. Environmental sex determination permits adaptive sex choice under unpredictable environmental conditions, where the environment affects sex-specific fitness, and where offspring can predict their likely adult status by monitoring an appropriate environmental cue. The parasitic copepod Pachypygus gibber displays three sexual phenotypes (i.e. one female and two kinds of male) which are environmentally determined (i.e. after conception and in response to environmental cues). Here, we report an experimental analysis on the combined action, during larval development, of availability of food resources and sexual partners in the sex determination of this species.

Becheikh, S.; Michaud, M.; Thomas, F.; Raibaut, A.; Renaud, F.



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


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

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



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

PubMed Central

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



Escape from viscosity: the kinematics and hydrodynamics of copepod foraging and escape swimming.  


Feeding and escape swimming in adult females of the calanoid copepod Temora longicornis Müller were investigated and compared. Swimming velocities were calculated using a 3-D filming setup. Foraging velocities ranged between 2 and 6 mm s(-1), while maximum velocities of up to 80 mm s(-1) were reached during escape responses. Foraging took place at Reynolds numbers between 2 and 6, indicating that viscous forces are considerable during this swimming mode. Inertial forces are much more important during escape responses, when Reynolds numbers of more than 100 are reached. High-speed film recordings at 500 frames s(-1) of the motion pattern of the feeding appendages and the escape movement of the swimming legs revealed that the two swimming modes are essentially very different. While foraging, the first three mouth appendages (antennae, mandibular palps and maxillules) create a backwards motion of water with a metachronal beating pattern. During escape movements the mouth appendages stop moving and the swimming legs beat in a very fast metachronal rhythm, accelerating a jet of water backwards. The large antennules are folded backwards, resulting in a streamlined body shape. Particle image velocimetry analysis of the flow around foraging and escaping copepods revealed that during foraging an asymmetrical vortex system is created on the ventral side of the animal. The feeding motion is steady over a long period of time. The rate of energy dissipation due to viscous friction relates directly to the energetic cost of the feeding current. During escape responses a vortex ring appears behind the animal, which dissipates over time. Several seconds after cessation of swimming leg movements, energy dissipation can still be measured. During escape responses the rate of energy dissipation due to viscous friction increases by up to two orders of magnitude compared to the rate when foraging. PMID:12477897

van Duren, Luca A; Videler, John J



Seasonal abundance and feeding patterns of copepods Temora longicornis , Centropages hamatus and Acartia spp. in the White Sea (66°N)  

Microsoft Academic Search

We have studied the seasonal dynamics of abundance and feeding characteristics of three species of calanoid copepods (Acartia spp., Centropages hamatus and Temora longicornis) in the White Sea from the surface water layer (0–10 m), in order to assess their role in the pelagic food web and to determine\\u000a the major factors governing their population dynamics during the productive season. These

Daria M. MartynovaNatalia; Natalia A. Kazus; Ulrich V. Bathmann; Martin Graeve; Alexey A. Sukhotin



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

PubMed Central

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

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



Temporal patterns in diversity and species composition of deep-sea benthic copepods in bathyal Sagami Bay, central Japan  

Microsoft Academic Search

Little is known about temporal changes in the diversity and species composition of deep-sea metazoan meiofauna and their relationships with changes in the food supply. Those changes were studied for benthic copepod assemblages based on 2-year time-series data at a bathyal site in Sagami Bay (1430 m depth), central Japan, where annual fluctuation in the abundance of benthic foraminiferans was previously

M. Shimanaga; H. Kitazato; Y. Shirayama



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



The role of ciliates, heterotrophic dinoflagellates and copepods in structuring spring plankton communities at Helgoland Roads, North Sea  

Microsoft Academic Search

Mesocosm experiments coupled with dilution grazing experiments were carried out during the phytoplankton spring bloom 2009.\\u000a The interactions between phytoplankton, microzooplankton and copepods were investigated using natural plankton communities\\u000a obtained from Helgoland Roads (54°11.3?N; 7°54.0?E), North Sea. In the absence of mesozooplankton grazers, the microzooplankton\\u000a rapidly responded to different prey availabilities; this was most pronounced for ciliates such as strombidiids

Martin G. J. LoderCedric; Cédric Meunier; Karen H. Wiltshire; Maarten Boersma; Nicole Aberle



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



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



Net and gross incorporation of nitrogen by marine copepods fed on 15N-labelled diatoms: Methodology and trophic studies  

Microsoft Academic Search

The stable isotope of nitrogen (15N) and an appropriate three-compartment model were used in two 24-h lasting feeding experiments to trace the flow of N through the copepod Acartia discaudata and Calanus helgolandicus fed on 15N-labelled Skeletonema costatum and Thalassiosira weissflogii, respectively. Details of the labelling technique and principles of the computation of N transport rates are given. At the

Dorothée Vincent; Gerd Slawyk; Stéphane L'Helguen; Géraldine Sarthou; Morgane Gallinari; Laurent Seuront; Benoît Sautour; Olivier Ragueneau



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



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


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

Kusk, K Ole; Wollenberger, Leah



Spatial and temporal patterns in the occurrence of peritrich ciliates as epibionts on calanoid copepods in the Chesapeake Bay, USA.  


We investigated temporal and spatial patterns of distribution in two peritrich ciliates (i.e. Zoothamnium intermedium and Epistylis sp.) living as epibionts on calanoid copepods (i.e. Acartia tonsa and Eurytemora affinis) in Chesapeake Bay. Net tow samples collected along the main axis of the Bay were analyzed to estimate the occurrence of epibionts on copepods and to explore relationships among infestation prevalence, host abundance, and environmental variables. Zoothamnium intermedium and Epistylis sp. colonized populations of A. tonsa during spring and summer months, while only Z. intermedium colonized E. affinis during spring. Occurrence of epibionts on copepods showed high interannual variation, marked seasonality, and geographic heterogeneity. Extensive statistical analyses rejected simple scenarios of interactions between epibiosis, environmental variables, and host density, suggesting a more complex dynamics for the system. Analyses of epibiont colonies and zooids per host area (i.e. the sum of width and length of the body including antennae and swimming legs calculated assuming a cylindrical shape) were also performed. Overall, epibiont infestation prevalence (i.e. colonies/host area) and load (i.e. zooids/host area) were higher on copepodites than on adults for both host species, suggesting a preferential attachment to juveniles, or a higher predation pressure on adult stages. Infestation density and loads of both epibiont species were higher on the cephalothorax and abdomen of A. tonsa and E. affinis in comparison to the antennae and swimming legs, suggesting that ciliates can more easily colonize less active parts of the host. PMID:15927000

Utz, Laura R P; Coats, D Wayne


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


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

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



Evolution in the deep sea: biological traits, ecology and phylogenetics of pelagic copepods.  


Deep-sea biodiversity has received increasing interest in the last decade, mainly focusing on benthic communities. In contrast, studies of zooplankton in the meso- to bathypelagic zones are relatively scarce. In order to explore evolutionary processes in the pelagic deep sea, the present study focuses on copepods of two clausocalanoid families, Euchaetidae and Aetideidae, which are abundant and species-rich in the deep-sea pelagic realm. Molecular phylogenies based on concatenated-portioned data on 18S, 28S and internal transcribed spacer 2 (ITS2), as well as mitochondrial cytochrome c oxidase subunit I (COI), were examined on 13 species, mainly from Arctic and Antarctic regions, together with species-specific biological traits (i.e. vertical occurrence, feeding behaviour, dietary preferences, energy storage, and reproductive strategy). Relationships were resolved on genus, species and even sub-species levels, the latter two established by COI with maximum average genetic distances ranging from ?5.3% at the intra-specific, and 20.6% at the inter-specific level. There is no resolution at a family level, emphasising the state of Euchaetidae and Aetideidae as sister families and suggesting a fast radiation of these lineages, a hypothesis which is further supported by biological parameters. Euchaetidae were similar in lipid-specific energy storage, reproductive strategy, as well as feeding behaviour and dietary preference. In contrast, Aetideidae were more diverse, comprising a variety of characteristics ranging from similar adaptations within Paraeuchaeta, to genera consisting of species with completely different reproductive and feeding ecologies. Reproductive strategies were generally similar within each aetideid genus, but differed between genera. Closely related species (congeners), which were similar in the aforementioned biological and ecological traits, generally occurred in different depth layers, suggesting that vertical partitioning of the water column represents an important mechanism in the speciation processes for these deep-sea copepods. High COI divergence between Arctic and Antarctic specimens of the mesopelagic cosmopolitan Gaetanus tenuispinus and the bipolar Aetideopsis minor suggest different geographic forms, potentially cryptic species or sibling species. On the contrary, Arctic and Antarctic individuals of the bathypelagic cosmopolitans Gaetanus brevispinus and Paraeuchaeta barbata were very similar in COI sequence, suggesting more gene flow at depth and/or that driving forces for speciation were less pronounced in bathypelagic than at mesopelagic depths. PMID:22842293

Laakmann, Silke; Auel, Holger; Kochzius, Marc



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


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 716bp 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 96h in a time-course experiment. UV-B radiation led to a decreased pattern of the TJ-CHH transcript 48h and more after radiation (12kJ/m(2)). After exposure of a fixed dose (12kJ/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 96h. Also, the level of the TJ-CHH transcript was significantly up-regulated at 20% of WAFs after exposure to WAFs for 48h 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



Acute silver toxicity in the euryhaline copepod Acartia tonsa: influence of salinity and food.  


The euryhaline copepod Acartia tonsa was exposed to silver (AgNO(3)) in either the absence or the presence of food (diatom Thalassiosira weissflogii; 2 x 10(4) cells/ml). Standard static-renewal toxicity tests that included a fixed photoperiod of 16: 8 h light:dark and temperature (20 degrees C) were run in three different salinities (5, 15, and 30 ppt) together with measurements of pH, ions (Na(+), Cl(-), K(+), SO(4)(2-), Mg(2+), and Ca(2+)), alkalinity, dissolved organic carbon, and total and dissolved (0.45 microm) silver concentrations in the experimental media. In the absence of food, the 48-h EC50 (concentration causing effect to 50% of the individuals tested) values based on total and dissolved silver concentrations were 11.6, 87.2, and 163.2 microg Ag/L and 7.1, 79.2, and 154.6 microg Ag/L at salinities 5, 15, and 30 ppt, respectively. In the presence of food, they were 62.1, 98.5, and 238.4 microg Ag/L and 48.4, 52.3, and 190.9 microg Ag/L, respectively. In all experimental conditions, most of the toxic silver fraction was in the dissolved phase, regardless of salinity or the presence of food in the water. In either the absence or the presence of food, acute silver toxicity was salinity dependent, decreasing as salinity increased. Data indicate that changes in water chemistry can account for the differences in acute silver toxicity in the absence of food, but not in the presence of food, suggesting that A. tonsa requires extra energy to cope with the stressful conditions imposed by acute silver exposure and ionoregulatory requirements in low salinities. These findings indicate the need for incorporation of both salinity and food (organic carbon) in a future biotic ligand model (BLM) version for estuarine and marine conditions, which could be validated and calibrated using the euryhaline copepod A. tonsa. PMID:17867869

Pedroso, Mariana Saia; Bersano, José Guilherme Filho; Bianchini, Adalto



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

NASA Astrophysics Data System (ADS)

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

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



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



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


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



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


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

Lee, Carol Eunmi; Petersen, Christine H


Role of kairomones in host location of the pennellid copepod parasite, Lernaeocera branchialis (L. 1767).  


The life cycle of the parasitic copepod Lernaeocera branchialis involves 2 hosts, typically a pleuronectiform host upon which development of larvae and mating of adults occurs and a subsequent gadoid host, upon which the adult female feeds and reproduces. Both the copepodid and adult female stages must therefore locate and identify a suitable host to continue the life cycle. Several mechanisms are potentially involved in locating a host and ensuring its suitability for infection. These may include mechano-reception to detect host movement and chemo-reception to recognize host-associated chemical cues, or kairomones. The aim of this study was to identify the role of kairomones in host location by adult L. branchialis, by analysing their behaviour in response to fish-derived chemicals. Experiments demonstrated that water conditioned by immersion of whiting, Merlangius merlangus, elicited host-seeking behaviour in L. branchialis, whereas cod- (Gadus morhua) conditioned water did not. Lernaeocera branchialis are considered a genetically homogeneous population infecting a range of gadoids. However, their differential response to whiting- and cod-derived chemicals in this study suggests that either there are genetically determined subspecies of L. branchialis or there is some form of environmental pre-conditioning that allows the parasite to preferentially recognize the host species from which it originated. PMID:23369461

Brooker, A J; Shinn, A P; Souissi, S; Bron, J E



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.



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

PubMed Central

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

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



Influence of the monsoon climate on the distribution of neuston copepods in the Northeastern Indian ocean  

NASA Astrophysics Data System (ADS)

The horizontal distribution of the near-surface (neuston) copepods of the family Pontellidae was studied on the meridional transects through the central part of the Indian ocean between 12°N and 12°S and in the Bay of Bengal in the summer monsoon period. Eleven species of neuston pontellids were found. The common species Labidocera detruncate and Pontellopsis villosa have the sane high frequencies in the central part of the ocean and in the Bay of Bengal. Some species are rarer in the Bay of Bengal than in the central part of the ocean. In contrast, other species are more frequent in the Bay of Bengal. The special traits of the distribution in the Bay of Bengal coincide with the lower salinity in the bay than in the central ocean. The distribution of some neritic species from the Bay of Bengal to the south is dependent on the intensification of the water translocation to the south in the summer. In the central part of the Indian Ocean, the distribution of the common neustonic pontellids is similar in the periods of the summer and winter monsoons. It is the result of the occupation of the region by the same equatorial water masses.

Heinrich, A. K.



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


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

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



Acute and chronic bioassays with New Zealand freshwater copepods using pentachlorophenol  

SciTech Connect

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

Willis, K.J.



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


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



Very Bright Green Fluorescent Proteins from the Pontellid Copepod Pontella mimocerami  

PubMed Central

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

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



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


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


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.

Goetze, Erica



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


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



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.

Vehmaa, Anu; Brutemark, Andreas; Engstrom-Ost, Jonna



Feeding deterrent and toxicity effects of apo-fucoxanthinoids and phycotoxins on a marine copepod ( Tigriopus californicus )  

Microsoft Academic Search

Using the marine harpacticoid copepod Tigriopus californicus, the effects of phytoplankton feeding deterrents and toxins were differentiated and measured. Eight compounds were tested\\u000a for feeding deterrence and toxicity responses: four apo-fucoxanthinoids (apo-10?-fucoxanthinal, apo-12?-fucoxanthinal, apo-12-fucoxanthinal,\\u000a and apo-13?-fucoxanthinone) and four well-known phycotoxins (domoic acid, okadaic acid, microcystin-LR, and a mixture of PSP-1\\u000a toxins). Since several of these compounds exhibited both feeding deterrence

B. A. Shaw; R. J. Andersen; P. J. Harrison



Population genetic responses of the planktonic copepod Metridia pacifica to a coastal eddy in the California Current  

NASA Astrophysics Data System (ADS)

Despite the intermixing that planktonic populations might be expected to experience in the ocean's fluid regime, zooplankton species may be subdivided across their range into genetically distinct populations. This subdivision, or population genetic structure, may be generated by the interplay of biological processes (reproduction, dispersal, differential mortality) and physical forces governing planktonic distributions. Significant population genetic structure in the planktonic copepod Metridia pacifica occurred during a period of upwelling in the coastal transition zone off the west coast of the United States during April and May 1987. During this period a coastal eddy of saline, recently upwelled water was bordered by a southward flowing current stream; offshore waters were nutrient poor and slower flowing. Metridia pacifica was the most abundant copepod in zooplankton samples collected in this domain; the species was sufficiently abundant in 16 samples to allow genetic analysis. Individual copepods were assayed for allozymic variability by polyacrylamide gel electrophoresis. The samples were genetically heterogeneous (by a contingency chi-square analysis of allozymic frequencies). The genetic differentiation of the samples was characteristic of geographically separated conspecific populations. Cladistic (tree building) analyses were used to visualize the genetic relatedness of the 16 samples, based on the similarity of allozymic frequencies. This analysis resulted in two heterogeneous groups (of five and six samples each) and five anomalous samples that neither constituted a third group nor belonged to the two groups. Overlay of these groupings on the dynamic height topographies showed a concordance between the population genetic and oceanographic structures. Five of the six offshore samples belonged to one group; the five samples of the other group were found either in the eddy (two of three central eddy samples) or in the current jet. The remaining five samples were scattered in nearshore regions or in the frontal region between the eddy and offshore. The division of the samples into eddy and offshore groups may result from redistribution by currents of planktonic populations of different geographic origin and distinct genetic character. Thus the eddy may have entrained copepod populations originating from different source regions than the populations in offshore waters. Further genetic analysis on appropriate time and space scales will be required to determine the mechanisms generating structure in oceanic zooplankton.

Bucklin, Ann



Predicting the effects of coastal hypoxia on vital rates of the planktonic copepod Acartia tonsa Dana.  


We describe a model predicting the effects of low environmental oxygen on vital rates (egg production, somatic growth, and mortality) of the coastal planktonic copepod Acartia tonsa. Hypoxic conditions can result in respiration rate being directly limited by oxygen availability. We hypothesized that A. tonsa egg production, somatic growth, and ingestion rates would all respond in a similar manner to low oxygen conditions, as a result of oxygen dependent changes in respiration rate. Rate data for A. tonsa egg production, somatic growth, and ingestion under low environmental oxygen were compiled from the literature and from supplementary experiments. The response of these rates to oxygen was compared by converting all to the analogous units in terms of oxygen utilization, which we termed analogous respiration rate. These analogous respiration rates, along with published measurements of respiration rates, were used to parameterize and evaluate the relationship between A. tonsa respiration rate and environmental oxygen. At 18 °C, our results suggest that A. tonsa experiences sub-lethal effects of hypoxia below an oxygen partial pressure of 8.1 kPa (~3.1 mg L(-1) = 2.3 mL L(-1)). The results of this study can be used to predict the effects of hypoxia on A. tonsa growth and mortality as related to environmental temperature and oxygen partial pressure. Such predictions will be useful as a way to incorporate the effects of coastal hypoxia into population, community, or ecosystem level models that include A. tonsa. This approach can also be used to characterize the effects of hypoxia on other aquatic organisms. PMID:23691134

Elliott, David T; Pierson, James J; Roman, Michael R



Egg production of a marine planktonic copepod in relation to its food supply: laboratory studies  

SciTech Connect

Egg production by Paracalanus parvus, a particle-grazing copepod, was investigated in relation to its food supply. The concentration of available food (P) and the rates of ingestion (I) and egg production (B) were measured simultaneously at intervals of 6 h to 2 d for periods of 2-10 d. concentration, chemical composition (carbon and nitrogen), and species of phytoplankton were experimental variables. Egg production was related to the food ingested during the previous day. For one food type, I and B were rectilinear functions of P. The average maximum rates of ingestion and egg production were 1.1 N female /sup -1/d/sup -1/ and 53 eggs female /sup -1/d/sup -1/, equivalent to specific rates of 1.5 and 0.37 d/sup -1/. B was proportional to I below a critical ingestion rate, I/sub c/, and independent of I above I/sub c/. For II/sub c/, B.I/sup -1/ declined in terms of both carbon and nitrogen. These results, together with the ratio of C:N in particulate matter in the sea off southern California, suggest that nitrogen (hence protein) potentially limits egg production by adult female Paracalanus and that ingested carbon is used inefficiently.

Checkley, D.M. Jr.



Two copepod species largely confused: Asterocheres echinicola (Norman, 1868) and A. violaceus (Claus, 1889). Taxonomical implications  

NASA Astrophysics Data System (ADS)

Due to its extremely brief description, Asterocheres echinicola (Norman, 1868) has been confused with some Asterocheres species such as Asterocheres suberitis Giesbrecht, 1897, Asterocheres parvus Giesbrecht, 1897 and Asterocheres latus (Brady, 1872). Furthermore, this species has been considered conspecific with Cyclopicera lata (Brady, 1872) and Asterocheres kervillei Canu, 1898. The objective of this paper is to study the syntypes of Asterocheres echinicola deposited in the Museum of Natural History of London together with abundant material from this and other institutions. Re-examination of these syntypes revealed that Asterocheres echinicola was conspecific with the currently known Asterocheres species, A. violaceus. Therefore, this latter species should be considered as a junior synonym of the former. The specimens described by Brady as Cyclopicera lata represent distinctively Asterocheres echinicola (= Asterocheres violaceus) and are identical to Sars’s Ascomyzom parvum and to Giesbrecht’s Asterocheres echinicola. We propose to rename Cyclopicera lata as Asterocheres latus (Brady, 1872), and raise Sars’ Ascomyzon latus, a species which is different from Asterocheres echinicola (= Asterocheres violaceus) and from Asterocheres latus (= Cyclopicera lata), as a new species. In this paper, we not only redescribe both species A. echinicola and A. latus, but also compare them with their previous descriptions, with the new material available and with their congeners. The redescription of Asterocheres latus revealed new specific differences between this species and Asterocheres kervillei, a species considered as synonymous of Asterocheres latus for almost 40 years. We strongly recommend that these differences are sufficient to consider these two species different. Finally, we analyzed the implications of all these taxonomical changes with respect to the diversity of the hosts utilized by these copepods and their geographical distribution.

Bandera, M. Eugenia; Conradi, Mercedes



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.



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

PubMed Central

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

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



Dietary carotenoids regulate astaxanthin content of copepods and modulate their susceptibility to UV light and copper toxicity.  


High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal). Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC(50) values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers. PMID:22822352

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



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


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

Magnusson, Kerstin; Tiselius, Peter



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

Microsoft Academic Search

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

G. C Cripps; H. J Hill



Response of microzooplankton (protists and small copepods) to an iron-induced phytoplankton bloom in the Southern Ocean (EisenEx)  

NASA Astrophysics Data System (ADS)

The dynamics, composition and grazing impact of microzooplankton were studied during the in situ iron fertilisation experiment EisenEx in the Antarctic Polar Frontal Zone in austral spring (November 2000). During the 21 day experiment, protozooplankton and small metazooplankton were sampled from the mixed layer inside and outside the patch using Niskin bottles. Aplastidic dinoflagellates increased threefold in abundance and biomass in the first 10 days of the experiment, but decreased thereafter to values twofold higher than pre-fertilisation values. The decline after day 10 is attributed to increasing grazing pressure by copepods. They also constrained ciliate abundances and biomass which were higher inside the fertilised patch than outside but highly variable. Copepod nauplii abundance remained stable whereas biomass doubled. Numbers of copepodites and adults of small copepod species (<1.5 mm) increased threefold inside the patch, but doubled in surrounding waters. Grazing rates estimated using the dilution method suggest that microzooplankton grazing constrained pico- and nanoplankton populations, but species capable of feeding on large diatoms (dinoflagellates and small copepods including possibly nauplii) were selectively predated by the metazoan community. Thus, iron fertilisation of a developing spring phytoplankton assemblage resulted in a trophic cascade which favoured dominance of the bloom by large diatoms.

Henjes, Joachim; Assmy, Philipp; Klaas, Christine; Verity, Peter; Smetacek, Victor



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

Microsoft Academic Search

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

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



The Pathologic Copepod Phrixocephalus cincinnatus (Copepoda: Pennellidae) in the Eye of Arrowtooth Flounder, Atherestes stomias, and Rex Sole, Glyptocephalus zachirus, from British Columbia  

Microsoft Academic Search

We report Phrixocephalus cincinnatus, a pennellid copepod infecting the eyes of flatfishes, from a single specimen of rex sole, Glyptocephalus zachirus, for the first time. In the typical host, the arrowtooth flounder, Atherestes stomias, the parasite occurred commonly in sampled populations from the Broughton Archipelago in British Columbia, infected primarily the right eye of the flounder, and on only one

Reginald B. Blaylock; Robin M. Overstreet; Alexandra B. Morton



Grazing of toxic dinoflagellates, Alexandrium spp., by adult copepods of coastal Maine: Implications for the fate of paralytic shellfish toxins in marine food webs  

Microsoft Academic Search

Dinoflagellates of the genus Alexandrium synthesize potent neurotoxins known as paralytic shellfish poisoning (PSP) toxins. The grazing responses of two abundant copepod species from the Gulf of Maine, Acartia tonsa and Eurytemora herdmani, were compared using cultured isolates of Alexandrium spp., which differed in toxicity per cell and toxin composition and a non-toxic dinoflagellate Lingulodinium polyedrum. Additional experiments were performed

Gregory J. Teegarden; Allan D. Cembella



The effect of temperature on the development of egg, naupliar and copepodite stages of two species of copepods, Cyclops vicinus uljanin and Eudiaptomus gracilis sars  

Microsoft Academic Search

The duration times of the eggs, nauplii and copepodites of Cyclops vicinus and Eudiaptomus gracilis were obtained, by experiment, at 5, 10, 15 and 20°C. In contrast with previously published work on copepod development, the ovigerous females, used in the cultures at these temperatures, were removed from a water storage reservoir when it was at, or close to the experimental

I. G. Munro



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

Microsoft Academic Search

A total of 50 bacterial isolates was obtained from the copepod Pseudocaligus fugu, which is a common parasite, collected from the body surface of the panther puffer Takifugu pardalis. On the basis of colony characteristics, these bacterial isolates were grouped into six types, of which only two (Types-I and -II) showed a high affinity for adhesion to the carapace of

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



Further description of the development of the digestive organs in Atlantic halibut (Hippoglossus hippoglossus) larvae, with notes on differential absorption of copepod and Artemia prey  

Microsoft Academic Search

Despite the scientific and commercial interest that Atlantic halibut has received over the past decade, little is known of the ontogeny of its digestive tract during larval development. The provision of enriched Artemia as prey has been associated with incomplete metamorphosis while improved development has been achieved using wild plankton e.g., copepods. The aim of the present study was to

Frédéric S Luizi; Brendan Gara; Robin J Shields; Niall R Bromage



Ecdysteroid concentrations through various life-stages of the meiobenthic harpacticoid copepod, Amphiascus tenuiremis and the benthic estuarine amphipod, Leptocheirus plumulosus  

Microsoft Academic Search

Endocrine function in arthropods has principally been characterized in insects and malacostracan crustaceans. However, meiofauna represent the most abundant metazoan marine taxa, with harpacticoid copepods comprising the second most abundant taxon. In addition, their diminutive biomass has made characterization of endocrine components difficult, so little is known about endocrine control of reproduction, molting, and growth in meiofauna. In this study,

David S. Block; Adriana C. Bejarano; G. Thomas Chandler



Comparison of six sewage effluents treated with different treatment technologies--population level responses in the harpacticoid copepod Nitocra spinipes.  


Since conventional treatment technologies may fail in removing many micro-pollutants, there is currently a focus on the potential of additional treatment technologies for improved sewage treatment. The aim of the present study was to evaluate six different effluents from Henriksdal Sewage Treatment Plant in Stockholm, Sweden. The effluents were; conventionally treated effluent (chemical phosphorous removal in combination with an activated sludge process, including biological nitrogen removal and a sand filter), with additional treatments individually added to the conventional treatment; active carbon filtration, ozonation at 5 mg l(-1), ozonation at 15 mg l(-1), ozonation at 5 mg l(-1)+moving bed biofilm reactor and irradiation with ultraviolet radiation+hydrogen peroxide. The evaluation was done by characterizing and comparing the effluents using a Lefkovitch matrix model based on a life cycle test with the harpacticoid copepod Nitocra spinipes, combined with analysis of juvenile development and survival over time. The conventionally treated effluent resulted in the most negative effects, leading to the conclusion that all additional treatments in the present study created effluents with less negative impacts on the copepod populations. The ozone treatments with the low dose treatment in particular, resulted in the overall least negative effects. Moving bed biofilm reactor combined with ozone did not improve the quality of the effluent in the sense that slightly more negative effects on the population abundance were seen for this treatment technology compared to ozonation alone. The active carbon treatment had more negative effects than the ozone treatments, most of which could possibly be explained by removal of essential metal ions. The effluent which was treated with ultraviolet radiation+hydrogen peroxide resulted in few developmental and survival effects over time, but still showed negative effects on the population level. Matrix population modeling proved a useful tool for biologically characterizing and comparing the effluents. Basing the assessment either on the individual level data (development and survival over time or total reproductive output) or the population level data (lambda values and projected population abundances) would not have resulted in the same conclusions as combining both analyses. The juvenile development and survival over time allowed for closer monitoring of the important molting process, whereas the population modeling provided an integrated measure of potential effects at the population level. If the dilution of the effluent in the recipient is considered, the biological effects recorded in the present study were not of substantial significance for the copepod populations, regardless of treatment technology. PMID:20022642

Lundström, Elin; Björlenius, Berndt; Brinkmann, Markus; Hollert, Henner; Persson, Jan-Olov; Breitholtz, Magnus



A new genus and species of hatschekiid copepod (Siphonostomatoida) from groupers (Actinopterygii: Serranidae) collected off the Ryukyu Archipelago, Japan.  


A new genus and species of copepod, Mihbaicola sakamakii n. g., n. sp., belonging to the siphonostomatoid family Hatschekiidae, is described based on the females collected from inside the tissue of the branchiostegal membrane in three species of the groupers, Epinephelus fasciatus (Forsskål) (type-host), E. merra Bloch and Cephalopholis leopardus (Lacépède), collected off Okinawa-jima Island and Iriomote-jima Island, Ryukyu Archipelago, North Pacific Ocean. The new genus can be distinguished from other hatschekiid genera by a combination of the following characters in the female: the head is composed of the cephalosome and the pedigerous somite; the cephalothorax is expanded into a pair of posteroventral lobes carrying leg 1; legs 1 and 2 are biramous and composed of the protopod and both rami are 2-segmented; leg 3 is absent; and leg 4 is represented by a rounded lobe with a chitinous pointed apical process. PMID:23263944

Uyeno, Daisuke



Qualitative use of Dynamic Energy Budget theory in ecotoxicology. Case study on oil contamination and Arctic copepods  

NASA Astrophysics Data System (ADS)

The Dynamic Energy Budget (DEB) theory provides a logic and consistent framework to evaluate ecotoxicological test results. Currently this framework is not regularly applied in ecotoxicology given perceived complexity and data needs. However, even in the case of low data availability the DEB theory is already useful. In this paper we apply the DEB theory to evaluate the results in three previously published papers on the effects of PAHs on Arctic copepods. Since these results do not allow for a quantitative application we used DEB qualitatively. The ecotoxicological results were thereby set in a wider ecological context and we found a logical explanation for an unexpected decline in hatching success described in one of these papers. Moreover, the DEB evaluation helped to derive relevant ecological questions that can guide future experimental work on this subject.

Klok, Chris; Hjorth, Morten; Dahllöf, Ingela



New host and ocean records for the copepod Ommatokoita elongata (Siphonostomatoida: Lernaeopodidae), a parasite of the eyes of sleeper sharks.  


Seven of 8 Pacific sleeper sharks (Somniosus pacificus Bigelow and Schroeder, 1944) captured in Prince William Sound, Alaska, were actively infected, and all 8 had been at one time infected with the parasitic copepod Ommatokoita elongata (Grant, 1827) (Siphonostomatoida: Lernaeopodidae). Active infections consisted of adult females and chalimus larvae that had attached to the corneas of the sharks' eyes. This report documents a new host record and possibly the only reliable record of this parasite from a host other than the Greenland shark, Somniosus microcephalus (Bloch and Schneider, 1801). It also documents the first time O. elongata has been identified outside of the Atlantic Ocean or its locally adjacent straits and seas. PMID:9920328

Benz, G W; Lucas, Z; Lowry, L F



Host response to the chondracanthid copepod Chondracanthus goldsmidi, a gill parasite of the striped trumpeter, Latris lineata (Forster), in Tasmania.  


The chondracanthid copepod, Chondracanthus goldsmidi is an ectoparasite of gills, inner opercula and nasal cavities of cultured striped trumpeter, Latris lineata (Forster). Whilst often present in high numbers (up to 60 parasites per host), little is known about its effect on striped trumpeter. In this study C. goldsmidi was associated with extensive epithelial hyperplasia and necrosis. Pathological changes were most pronounced near the parasite's attachment site, with papilloma-like growths surrounding the entire parasite resulting in deformation of the filament. The number of mucous cells increased near the parasite attachment sites on both the opercula and gills. Mast cells were absent in healthy gills; in contrast numerous mast cells were identified in the papilloma-like growths. Immunostaining identified piscidin-positive mast cells in the papilloma-like growths, presenting the first evidence of piscidin in the family Latridae. PMID:19912458

Andrews, M; Battaglene, S; Cobcroft, J; Adams, M; Noga, E; Nowak, B



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



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

NASA Astrophysics Data System (ADS)

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

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



Calanoid copepod eggs in sea-bottom muds. III. Effects of temperature, salinity and other factors on the hatching of resting eggs of Tortanus forcipatus  

Microsoft Academic Search

The “resting” eggs of a marine neritic copepod, Tortanus forcipatus Giesbrecht, recovered from sea-bottom sediment were hatched in the laboratory. Hatching occurred at temperatures of 13° to 30°C, no eggs hatched at 10°C. Temperatures around 25°C were found to be optimal for hatching, although the range of optimal temperatures for hatching was approximately 5°C lower in eggs stored for 14

S. Kasahara; T. Onbé; M. Kamigaki



Effects of a rapidly receding ice edge on the abundance, age structure and feeding of three dominant calanoid copepods in the Weddell Sea, Antarctica  

Microsoft Academic Search

Open-water, marginal-ice and in-ice zones were sampled in the Weddell Sea during November and December, 1993 in an effort\\u000a to examine the influence of the early spring bloom on the diet and population structure of the three biomass dominant copepods:\\u000a Metridia gerlachei, Calanus propinquus, and Calanoides acutus. The abundance of all three species in the upper 200?m was highest at

Scott E. Burghart; Thomas L. Hopkins; Gabriel A. Vargo; José J. Torres



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



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



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



Attenuation of the vertical flux of copepod fecal pellets under Arctic sea ice: evidence for an active detrital food web in winter  

Microsoft Academic Search

A variable fraction of fecal pellets produced in the epipelagic layer is intercepted and retained before reaching the bottom.\\u000a We assessed fecal pellet retention in the ice-covered Beaufort Sea in early February by comparing the shape and size-frequency\\u000a distribution of pellets collected by a sediment trap moored at 210 m to that produced in vitro. Appendicularian ellipsoidal\\u000a and copepod cylindrical pellets

Makoto Sampei; Alexandre Forest; Hiroshi Sasaki; Hiroshi Hattori; Ryosuke Makabe; Mitsuo Fukuchi; Louis Fortier



Cu\\/Zn and Mn-superoxide dismutase ( SOD) from the copepod Tigriopus japonicus: Molecular cloning and expression in response to environmental pollutants  

Microsoft Academic Search

Superoxide dismutase (SOD) is an important antioxidant enzyme which catalyzes conversion of superoxide to oxygen and hydrogen peroxide in aerobic organisms. Here, we cloned and sequenced the full-length cDNA and genomic DNA of two SODs from the copepod, Tigriopus japonicus: copper\\/zinc SOD (TJ-Cu\\/Zn-SOD) and manganese SOD (TJ-Mn-SOD). To define whether TJ-Mn-SOD is a cytosolic or a mitochondrial protein, a phylogenetic

Bo-Mi Kim; Jae-Sung Rhee; Gyung Soo Park; Jehee Lee; Young-Mi Lee; Jae-Seong Lee



Effects of photoperiod on egg production and hatching success, naupliar and copepodite development, adult sex ratio and life expectancy of the tropical calanoid copepod Acartia sinjiensis  

Microsoft Academic Search

The tropical calanoid copepod Acartia sinjiensis has good potential for mass culture as live feed for reef fish larvae. The present study was conducted to evaluate the effects of photoperiod on various parameters related to A. sinjiensis productivity in culture.Five photoperiods of Light:Dark=0:24; 6:18; 12:12; 18:6 and 24:0h were setup. Daily egg production of individual females under each photoperiod was

Thomas Camus; Chaoshu Zeng



Copepods and branchiopods of temporary ponds in the Doñana Natural Area (SW Spain): a four-decade record (1964–2007)  

Microsoft Academic Search

\\u000a The Doñana Natural Area includes a large array of wetlands with the highest degree of environmental protection in Spain, and\\u000a so it has long attracted many studies. We present a cumulative list of zooplankton taxa (Copepods and Branchiopods) based\\u000a on a collection of 18 publications (1964–2007) and 4 unpublished studies. Seventy-eight taxa have been recorded in a set of\\u000a 55

K. Fahd; A. Arechederra; M. Florencio; D. León; L. Serrano


Copepods and branchiopods of temporary ponds in the Doñana Natural Area (SW Spain): a four-decade record (1964–2007)  

Microsoft Academic Search

The Doñana Natural Area includes a large array of wetlands with the highest degree of environmental protection in Spain, and\\u000a so it has long attracted many studies. We present a cumulative list of zooplankton taxa (Copepods and Branchiopods) based\\u000a on a collection of 18 publications (1964–2007) and 4 unpublished studies. Seventy-eight taxa have been recorded in a set of\\u000a 55

K. Fahd; A. Arechederra; M. Florencio; D. León; L. Serrano



A novel microhabitat for parasitic copepods: a new genus of Ergasilidae (Copepoda: Cyclopoida) from the urinary bladder of a freshwater fish.  


An endoparasitic copepod is reported from the urinary bladder of a fish for the first time. Endoparasitic copepods on fish hosts are extremely rare and the impact of colonization of this novel microhabitat on the biology of the parasite is discussed. This curious association was reported from two different host families of Neotropical freshwater fishes, Erythrinidae and Cichlidae, collected from the Cristalino River, a tributary of the Araguaia River, in Brazil. The copepod is fully described using light and scanning electron microscopy. Urogasilus brasiliensis n. g., n. sp. represents a new genus and species of the family Ergasilidae and can be distinguished from other genera by its unique tagmosis, in which the fourth and fifth pedigerous somites and the genital double-somite are all fused to form an elongate trunk. The anal somite is the only free abdominal somite present. The pattern of leg segmentation is also unique, with legs 1 to 3 each having a 2-segmented endopod and leg 4 reduced to a single seta. The discovery of ovigerous female ergasilids in the urinary bladder of a fish is novel and this discovery represents a good model for further studies on the adaptations to an endoparasitic lifestyle. PMID:23523989

Rosim, Daniele F; Boxshall, Geoff A; Ceccarelli, Paulo S



[Species composition and distribution characteristics of pelagic copepods in the Northern Sea of Fujian during withdraw of Zhe-Min coastal current].  


Based on oceanographic survey data in April 2009 in the north central Taiwan Strait, ecological characteristics such as species composition, individual density, dominant species and distribution were analyzed. The results were compared with the same area survey in spring 2007 for discuss the annual variety. The result shows that 48 pelagic copepods species have been recognized, and most of them belongs to Calanodia. The higher species number occurs in southern and eastern area. The average density of pelagic copepoda was 231.96 ind x m(-3). As to the horizontal distribution, the coast and northern areas are higher than those of eastern and southern areas of the density of pelagic copepods which are dependent on the dominant species Calanus sinicus and Euchaeta plana. The community structure of pelagic copepoda was same to the other survey result, which shows low biodiversity index with remarkable dominant species. Owing to the Zhe-Min coastal current effect, the higher density distribution is different in 2007 and 2009. As to the ecological character, all the copepoda in this paper belong to warm-water, warm-temperature and tropic oceanic groups. Warm-water and tropic oceanic groups are the dominant groups of the pelagic copepods composition. When it comes to density, warm-temperature group is the dominant. The relationship of species number, diversity index and abundance with the environment were also discussed in this paper. The result showed that the pelagic copepoda species number and diversity would increase with the temperature and salty increase. PMID:22946163

Wang, Yan-Guo; Lin, Jing-Hong; Wang, Chun-Guang; Lin, Mao



The influence of phytoplankton productivity, temperature and environmental stability on the control of copepod diversity in the North East Atlantic  

NASA Astrophysics Data System (ADS)

The patterns of copepod species richness (S) and their relationship with phytoplankton productivity, temperature and environmental stability were investigated at climatological, seasonal and year-to-year time scales as well as scales along latitudinal and oceanic-neritic gradients using monthly time series of the Continuous Plankton Recorder (CPR) Survey collected in the North East Atlantic between 1958 and 2006. Time series analyses confirmed previously described geographic patterns. Equatorward and towards neritic environments, the climatological average of S increases and the variance explained by the seasonal cycle decreases. The bi-modal character of seasonality increases equatorward and the timing of the seasonal cycle takes place progressive earlier equatorward and towards neritic environments. In the long-term, the climatological average of S decreased significantly (p < 0.001) between 1958 and 2006 in the Bay of Biscay and North Iberian shelf at a rate of ca. 0.04 year-1, and increased at the same rate between 1991 and 2006 in the northernmost oceanic location. The climatological averages of S correlate positively with those of the index of seasonality of phytoplankton productivity (ratio between the minimum and maximum monthly values of surface chlorophyll) and sea surface temperature, and negatively with those of the proxy for environmental stability (monthly frequency of occurrence of daily averaged wind speed exceeding 10 m s-1). The seasonal cycles of S and phytoplankton productivity (surface chlorophyll as proxy) exhibit similar features in terms of shape, timing and explained variance, but the relationship between the climatological averages of both variables is non-significant. From year-to-year, the annual averages of S correlate negatively with those of phytoplankton productivity and positively with those of sea surface temperature along the latitudinal gradient, and negatively with those of environmental stability along the oceanic-neritic gradient. The annual anomalies of S (i.e. factoring out geographic variation) show a unimodal relationship with those of sea surface temperature and environmental stability, with S peaking at intermediate values of the anomalies of these variables. The results evidence the role of seasonality of phytoplankton productivity on the control of copepod species richness at seasonal and climatological scales, giving support to the species richness-productivity hypothesis. Although sea surface temperature (SST) is indeed a good predictor of richness along the latitudinal gradient, it is unable to predict the increase of richness form oceanic to neritic environments, thus lessening the generality of the species richness-energy hypothesis. Meteo-hydrographic disturbances (i.e. SST and wind speed anomalies as proxies), presumably through its role on mixed layer depth dynamics and turbulence and hence productivity, maximise local diversity when occurring at intermediate frequency and or intensity, thus providing support to the intermediate disturbance hypothesis on the control of copepod diversity.

Nogueira, Enrique; González-Nuevo, Gonzalo; Valdés, Luis



The influence of prey behaviour on prey selection of the carnivorous plant Utricularia vulgaris  

Microsoft Academic Search

The mechanisms underlying differential prey selection of two microcrustaceans by the common bladderwort (Utricularia vulgaris) were studied in the laboratory. Functional response experiments with single prey showed that Utricularia had a higher attack rate coefficient and a longer handling time coefficient with the cladoceran Polyphemus pediculus than with the cyclopoid copepod Eucyclops serrulatus. Observation of predation rate, defined as number

Sabine Harms; Frank Johansson



Three new species of Bomolochidae (Copepoda, Cyclopoida) from Tropical Atlantic Tunnies  

Microsoft Academic Search

Dr. J. F. Aldrin, Sous Direction de Pêche, Abidjan, Côte d'Ivoire, during an extensive survey of tropical Atlantic Tunnies, discovered the presence of Cyclopoid Copepods of the family Bomolochidae in the nasal fossae of three species of tunnies, viz., Euthynnus alleteratus (Rafinesque), Auxis thazard (Lacépède) and Sarda sarda (Bloch). The material was placed into my hands for study by mediation

W. Vervoort



The relationship between temperature and duration of egg development in some epiphytic cladocera and copepoda from the River Thames, reading, with a discussion of temperature functions  

Microsoft Academic Search

Data on the duration of egg development at 5, 10, 15 and 20°C are given for eight cladoceran and one cyclopoid copepod species found associated with the Yellow Water Lily (Nuphar lutea) in the River Thames. A decrease in temperature caused a marked increase in the time taken to complete development for all nine species. The data are compared with

Howard H. Bottrell



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


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

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



The effect of upwelling filaments and island-induced eddies on indices of feeding, respiration and growth in copepods  

NASA Astrophysics Data System (ADS)

Vertical (0 200 m) and horizontal distribution of two calanoid copepod species, Scolecithrix danae and Scottocalanus sp., were studied in relation to physical structures in the transition zone off Northwest Africa during the summer of 1999. Zooplankton biomass and indices of feeding (gut fluorescence, GF), respiration (electron transfer system activity, ETS) and structural growth (aminoacyl-tRNA synthetases activity, AARS) were assessed across (1) upwelling filaments, (2) a cyclonic eddy and (3) three anticyclonic island-induced eddies in the waters south of the Canary Islands. Hydrography was an important influence on the populations studied, enhancing their development by advecting chlorophyll enriched cold waters towards the open ocean. S. danae had highest rates in anticyclonic eddies at the limit of the upwelled waters. However, GF was more than two-fold higher inside the filaments than in the surrounding waters. Scottocalanus sp. occurred only inside the upwelling area and within upwelling filaments that advected them toward oceanic waters. The frontal zone south of Gran Canaria showed the highest AARS activities for both species.

Yebra, L.; Hernández-León, S.; Almeida, C.; Bécognée, P.; Rodríguez, J. M.



Parasitic copepods from two species of commercial fishes collected off Iraq, with description of Hatschekia shari n. sp.  


Two species of parasitic copepods, including one new species, are described based on specimens collected from off Basrah, Iraq (Arabian Gulf). Hatschekia shari n. sp. (Siphonostomatoida: Hatschekiidae) was found from the gill filaments of the spangled emperor Lethrinus nebulosus (Forsskål) (Perciformes: Lethrinidae). The new species is characterised by the following characters in the female: a rectangular cephalothorax with dorsal frame composed of two short and one long bifid longitudinal bars, connecting to one short and one long latitudinal bars; elongate, cylindrical trunk without posterolateral processes or lobes; absence of parabasal papillae; and antennae bearing middle segments without narrow median part and with terminal claws without basal conical processes. Bactrochondria formosana Ho, Lin & Liu, 2011 (Cyclopoida: Chondracanthidae) was found on the gill filaments of the largescale tonguesole Cynoglossus arel (Bloch & Schneider) (Pleuronectiformes: Cynoglossidae). Close comparison of the specimens of B. formosana collected from off Iraq with the original description revealed some differences in elements and ornamentations on the body and appendages. Our finding of B. formosana represents not only a new record from the Indian Ocean but also from a new host. PMID:24163030

Uyeno, Daisuke; Ali, Atheer H



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

NASA Astrophysics Data System (ADS)

The influence of microhabitat type on the diversity and community structure of the harpacticoid copepod fauna associated with a cold-water coral degradation zone was investigated in the Porcupine Seabight (North-East Atlantic). Three substrate types were distinguished: dead fragments of the cold-water coral Lophelia pertusa, skeletons of the glass sponge Aphrocallistes bocagei and the underlying sediment. At the family level, it appears that coral fragments and underlying sediment do not harbour distinctly different assemblages, with Ectinosomatidae, Ameiridae, Pseudotachidiidae, Argestidae and Miraciidae as most abundant. Conclusions on assemblage structure and diversity of the sponge skeletons are limited as only two samples were available. Similarity analysis at species level showed a strong variation in the sediment samples, which did not harbour a distinctly different assemblage in opposition to the coral and sponge samples. Several factors (sediment infill on the hard substrates, mobility of the copepods, limited sample sizes) are proposed to explain this apparent lack of a distinct difference between the microhabitats. Coral fragments and sediment were both characterised by high species diversity and low species dominance, which might indicate that copepod diversity is not substantially influenced by hydrodynamical stress. The additive partitioning of species diversity showed that by adding locations species richness was greatly enhanced. The harpacticoid community in the cold-water coral degradation zone is highly diverse and includes 157 species, 62 genera and 19 families. Information from neighbouring soft-bottom regions is necessary to assess whether total species diversity is increased by the presence of these complex habitat-providing substrates.

Gheerardyn, Hendrik; de Troch, Marleen; Vincx, Magda; Vanreusel, Ann



Acute copper toxicity in the euryhaline copepod Acartia tonsa: implications for the development of an estuarine and marine biotic ligand model.  


Copepods (Acartia tonsa) were exposed (48 h) to waterborne, diet-borne (non-Cu-equilibrated and Cu-equilibrated food), and waterborne plus diet-borne Cu in either the absence or the presence of food (diatom Thalassiosira weissflogii). Toxicity tests were run in different salinities (5, 15, and 30 ppt) together with measurements of physicochemical parameters and total and dissolved Cu concentrations in the experimental media. Results show that most of the toxic Cu fraction was in the dissolved phase. In general, Cu toxicity was higher in low (5 ppt) than in high salinity (30 ppt), regardless of the pathway of Cu exposure tested. In the absence of food, data clearly indicate that differences in waterborne Cu toxicity can be explained by changes in water chemistry. However, addition of food (either non-Cu-equilibrated or Cu-equilibrated) to the experimental media protected against acute Cu toxicity in salinities 5 and 15 ppt, suggesting that A. tonsa requires extra energy to cope with the stressful condition imposed by Cu exposure associated with the ionoregulatory requirements in low salinities. For diet-borne exposure, a very high Cu concentration was necessary to precontaminate the diatoms to a level resulting in copepod mortality. Therefore, availability of food exerted a more important positive impact in protecting against acute Cu toxicity than its potential negative impact via contamination resulting in toxicity. Findings indicate the need for incorporation of both salinity and food in a future biotic ligand model (BLM) version for Cu in estuarine and marine waters. In this context, the euryhaline copepod A. tonsa would be a suitable model species with which to perform experiments to validate and calibrate any future saltwater BLM. PMID:20821639

Pinho, Grasiela Lopes Leães; Bianchini, Adalto



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

PubMed Central

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

Uyeno, Daisuke; Wakabayashi, Kaori; Nagasawa, Kazuya



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

NASA Astrophysics Data System (ADS)

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

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



The effect of a biologically produced structure on the benthic copepods of a deep-sea site  

NASA Astrophysics Data System (ADS)

In deep-sea soft bottoms, a variety of organisms produce structures that persist for long periods, even after the structures are vacated. It has been hypothesized that these structures are a major source of patchiness in these communities and are important in maintaining the high diversities that characterize the deep sea. Although several studies have shown species' abundances to be correlated with structures, the mechanisms underlying the associations are not known. We attempted to discover these mechanisms, focusing on the responses of benthic copepods to mudballs made by the polychaete Tharyx luticastellus at a site at 1050 m depth in San Diego Trough (32° 52.4'N, 117°45.5'W). It was found that seven out of 40 species responded. Four were more abundant around the structure only when the worm was in residence. These species apparently benefit from some consequences of the worm's presence. Given that bacterial abundance is higher about occupied Tharyx mudballs than nearby controls, it may be that the attractiveness occupied Tharyx mudballs arises from the provision of food. Three species responded to unoccupied mudballs. We measured responses to various types of mudball mimics to determine whether responses were to a habitat provided by the mudball, to a refuge from predation in its vicinity, or to hydrodynamically mediated increases in local food availability. Two of the species appeared to use the mudball as a habitat, the third as a refuge from infaunal predators. The results indicate that biologically produced structures can persist long enough to be viewed as habitat heterogeneity by other species in the community and that this source of patchiness is important to deep-sea species.

Thistle, David; Eckman, James E.



Phylogeography of Calanus helgolandicus and the Black Sea copepod Calanus euxinus, with notes on Pseudocalanus elongatus (Copepoda, Calanoida)  

NASA Astrophysics Data System (ADS)

Calanus helgolandicus is a widespread epipelagic copepod species whose geographical range extends from the temperate Atlantic Ocean to the northern Mediterranean Sea. Calanus euxinus, recently designated as a distinct species though closely related to C. helgolandicus, occurs in the Black Sea. Very subtle morphological differences distinguish the two species. Pseudocalanus elongatus has a similar geographic range including North Atlantic Ocean, Mediterranean Sea and the Black Sea. In this study, population genetic variation of C. helgolandicus, C. euxinus and P. elongatus was investigated using DNA sequence variation of 540 base pair ( Calanus spp.) and 575 base pair ( P. elongatus) regions of mitochondrial cytochrome oxidase I (mtCOI) gene. C. helgolandicus was collected from the English Channel, the Adriatic Sea, and C. euxinus was collected from various regions of the Black Sea. P. elongatus was collected from the English Channel and the Black Sea. Intraspecific differentiation in mtCOI was <1% for all species; mtCOI sequence variation between C. helgolandicus and C. euxinus was <0.5%. The absence of substantial genetic differentiation between C. helgolandicus and C. euxinus is particularly striking in comparison to other close species pairs in these genera. Statistically significant haplotype frequency differences were determined for different locations of the Black Sea, English Channel, and Adriatic Sea Calanus populations ( ?2=3.94, P<0.0001). The haplotype diversity was high for all species: C. euxinus ( h=0.92), C. helgolandicus ( h?0.80), P. elongatus ( h?0.60). No haplotype sharing was reported for different locations of P. elongatus, whereas the presence of haplotype sharing between C. helgolandicus and C. euxinus was remarkable. The size distribution in terms of prosome length measurements was found to be region-specific. The lack of phylogenetic differentiation between the Calanus species pair may suggest ancestral polymorphisms. The morphological and genetic similarities between C. euxinus and C. helgolandicus raise new questions about the status of C. euxinus as a different species.

Unal, Ebru; Frost, Bruce W.; Armbrust, Virginia; Kideys, Ahmet E.



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



A critical body residue approach for predicting persistent bioaccumulative toxicant effects on reproduction and population dynamics of meiobenthic copepods.  


Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose-response on a dry-weight or lipid-normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E-2317-14) produced biomass sufficient for dry mass and lipid-normalized CBR estimates of reproduction (fertility) and population growth suppression. Significant FS toxic effects were delayed naupliar development (at ?0.10?µg?L(-1)), delayed copepodite development (at 0.85?µg?L(-1)), decreased reproductive success (at ? 0.39?µg?L(-1)), and decreased offspring production (at 0.85?µg?L(-1)). A reproductive median effective concentration (EC50) of 0.16?µg?L(-1) (95% CI: 0.12-0.21?µg?L(-1)) corresponded to an adult all-sex CBR and lipid-normalized CBR of 0.38?pg FS?·?µg(-1) dry weight (95% CI: 0.27-0.52?pg FS?·?µg(-1)) or 2.8?pg FS?·?µg(-1) lipid (95% CI: 2.2-3.6?pg FS?·?µg(-1)), respectively. Copepod log bioconcentration factor (BCF)?=?4.11?±?0.2. Leslie matrix projections regressed against internal dose predicted fewer than five gravid females in a population by the third generation at 0.39 and 0.85?µg FS?·?L(-1) (i.e., 9.6-10.2?µg FS?·?µg(-1) lipid), and 50% population suppression at a CBR of 1.6?pg FS?·?µg(-1) lipid. This more integrative population CBR as a management tool would fall 1.75 times below the CBR for the single most sensitive endpoint-fertility rate. PMID:22331616

Chandler, G Thomas; Ferguson, P Lee; Klauber, W W; Washburn, K M



Expression profile analysis of antioxidative stress and developmental pathway genes in the manganese-exposed intertidal copepod Tigriopus japonicus with 6K oligochip.  


Manganese (Mn) provides one of aquatic pollutants in marine ecosystem. Here we used a 6K oligomicroarray to identify the effect of Mn on transcriptomes in the copepod Tigriopus japonicus. A total of 5594 spots were significantly modulated on a 6K oligomicroarray with hierarchical clustering after exposure to Mn over 24h. Of them, 186 and 489 genes were significantly upregulated and downregulated, respectively. Particularly, several genes involved in stress, detoxification, and developmental functions were significantly modulated in T. japonicus exposed for 24h. In detail, Mn exposure specifically up-regulated genes that were related to intracellular stress, antioxidant, and detoxification pathways such as cytochrome P450s (CYPs), glutathione S-transferases (GSTs), and heat shock proteins (hsps), while a majority of downregulated genes was associated with developmental pathways such as cuticle protein, ecdysone receptor, and vitellogenin. These results demonstrated that Mn exposure modulated gene expression in relation to intracellular stress, leading to developmental retardation in the intertidal copepod, T. japonicus, and provide a better understanding of mechanistic molecular studies of Mn-induced cellular damage. PMID:23714145

Kim, Bo-Mi; Choi, Beom-Soon; Lee, Kyun-Woo; Ki, Jang-Seu; Kim, Il-Chan; Choi, Ik-Young; Rhee, Jae-Sung; Lee, Jae-Seong



Infestations of wild adult Atlantic salmon (Salmo salar L.) by the ectoparasitic copepod sea louse Lepeophtheirus salmonis Krøyer: prevalence, intensity and the spatial distribution of males and [2pt] females on the host fish  

Microsoft Academic Search

The copepod Lepeophtheirus salmonis Krøyer is a specific ectoparasite of North Atlantic and Pacific salmonids in their marine phases. We compared infestations of L. salmonis on wild Atlantic salmon (Salmo salarL.) captured in estuarine (Firth of Tay, east Scotland; 1995, 1996) and marine coastal waters (Strathy Point, north Scotland; 1998, 1999). Host fish from the Tay were caught by sweep

Christopher D. Todd; Alan M. Walker; Jane E. Hoyle; Sally J. Northcott; Andrew F. Walker; Michael G. Ritchie



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.


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



Gyrodinium undulans Hulburt, a marine dinoflagellate feeding on the bloom-forming diatom Odontella aurita, and on copepod and rotifer eggs  

NASA Astrophysics Data System (ADS)

The marine dinoflagellate Gyrodinium undulans was discovered as a feeder on the planktonic diatom Odontella aurita. Every year, during winter and early spring, a certain percentage of cells of this bloom-forming diatom, in the Wadden Sea along the North Sea coast, was regularly found affected by the flagellate. Supplied with the food diatom O. aurita the dinoflagellate could be maintained successfully in clonal culture. The vegetative life cylce was studied, mainly by light microscopy on live material, with special regard to the mode of food uptake. Food is taken up by a so-called phagopod, emerging from the antapex of the flagellate. Only fluid or tiny prey material could be transported through the phagopod. Larger organelles like the chloroplasts of Odontella are not ingested and are left behind in the diatom cell. Thereafter, the detached dinoflagellate reproduces by cell division, occasionally followed by a second division. As yet, stages of sexual reproduction and possible formation of resting cysts could not be recognized, neither from wild material nor from laboratory cultures. Palmelloid stages (sometimes with a delicate wall) occurring in ageing cultures may at least partly function as temporary resting stages. The winter species G. undulans strongly resembles Syltodinium listii, a summer species feeding on copepod and rotifer eggs. Surprisingly, in a few cases this prey material was accepted by G. undulans as well, at least under culture conditions. When fed with copepod eggs, the dinoflagellate developed into a large trophont, giving rise thereafter by repeated binary fission to 4, 8 or 16 flagellates, as a result of a single feeding act. A re-examination of both species under simultaneous culture conditions is planned.

Drebes, G.; Schnepf, E.



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

PubMed Central

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



Food and feeding of Aurelia aurita in Tokyo Bay with an analysis of stomach contents and a measurement of digestion times  

Microsoft Academic Search

In situ seasonal variations in stomach contents of Aurelia aurita (L.) in Tokyo Bay, Japan, were analyzed. Copepods, such as Oithona davisae Ferrari & Orsi were the predominant food items of A. aurita from June to November. The mean digestion time measured in incubation experiments was 0.95 h. Daily rations calculated using stomach content data and digestion times were 2.2–21.8

Haruto Ishii; Fusako Tanaka



Detection of zooplankton items in the stomach and gut content of larval krill, Euphausia superba , using a molecular approach  

Microsoft Academic Search

The usefulness of a molecular approach based on polymerase chain reaction (PCR) was investigated to identify and quantify\\u000a the feeding of larval krill on zooplankton organisms in the Lazarev Sea during winter in 2006. Different primers and probes\\u000a of dominant copepod species (Oithona sp., Ctenocalanus citer, copepodid stages of Metridia gerlachei and Calanoides acutus), co-occurring with larval krill under sea

Kerstin Töbe; Bettina Meyer; Veronica Fuentes



Winter studies on zooplankton in Arctic seas: the Storfjord (Svalbard) and adjacent ice-covered Barents Sea  

Microsoft Academic Search

Zooplankton was sampled in the Storfjord and ice-covered Barents Sea during March 2003. Environmental conditions represented\\u000a a typical winter situation with low air temperatures, close pack ice, and extremely low chlorophyll concentrations. Polar\\u000a water dominated the hydrographic regime in the upper layers. Zooplankton distribution reflected spatial variability of hydrography.\\u000a The copepods Pseudocalanus spp., Oithona similis, Microsetella norvegica together with gastropod

H. J. Hirche; K. N. Kosobokova


Population growth capacities and regulatory factors in monospecific cultures of the cladocerans Moina micrura and Diaphanosoma excisum and the copepod Thermocyclops decipiens from Côte d’Ivoire (West Africa)  

Microsoft Academic Search

The cladocerans Moina micrura and Diaphanosoma excisum and the copepod Thermocyclops decipiens were studied in microcosms (0.8 m3) under semi-controlled experimental conditions at 25–29 °C for 32 days, by daily sampling after an initial monospecific inoculation. For each species, the time series began with an exponential population growth phase. M. micrura showed a higher daily population growth rate (mean = 1.19)

Marc Pagano; Lucien Saint-Jean; Robert Arfi; Marc Bouvy; Helguilé Shep



Sequence, biochemical characteristics and expression of a novel Sigma-class of glutathione S-transferase from the intertidal copepod, Tigriopus japonicus with a possible role in antioxidant defense  

Microsoft Academic Search

Glutathione S-transferases (GSTs) play a major role in detoxification of xenobiotics and antioxidant defense. Here we report full-length cDNA sequence of a novel Sigma-class of GST (GST-S) from the intertidal copepod Tigriopus japonicus. The full sequence was of 1136bp in length containing an open reading frame (ORF) of 651bp that encoded 217 amino acid residues. The recombinant Tigriopus GST-S was

Young-Mi Lee; Kyun-Woo Lee; Hyun Park; Heum Gi Park; Sheikh Raisuddin; In-Young Ahn; Jae-Seong Lee



Species diversity and vertical distribution of the deep-sea copepods of the genus Euaugaptilus in the Sulu and Celebes Seas  

NASA Astrophysics Data System (ADS)

The relationships between water-column structure, species diversity and patterns of vertical distribution were examined in the copepod genus Euaugaptilus in the Sulu and Celebes Seas. Euaugaptilus is among the most species-rich single genus of all calanoid copepods and is characterized by the specialized 'button setae' in their mouth appendages. The Sulu Sea is a semi-enclosed equatorial basin located in the center of the Indo-Malayan Archipelago, rimmed by sills shallower than 420 m, and characterized by homogeneous, warm water (ca. 10 °C) from the mesopelagic zone to the sea bottom of ca. 5000 m, while the adjacent Celebes Sea is of more typical oceanic conditions. Plankton samples were collected at two stations both day and night from 16 discrete layers in the upper 1000 m. A total of 29 species of Euaugaptilus were collected in the Celebes Sea, which is among the largest numbers for the genus so far reported from a single restricted sea area, but only 8 species were collected in the Sulu Sea. These 8 species occurred in the upper mesopelagic zone in the Celebes Sea, while in the Sulu Sea many of them extended their ranges and/or shifted into deeper zones. An additional 15 net tows to depths deeper than 1000 m added 6 species from the Celebes Sea and 8 species from the Sulu Sea, with all the deep Sulu species, except E. hyperboreus, being found above 1000 m in the Celebes Sea. This drastic reduction of species number in the Sulu Sea is attributed to the homogenous high-temperature deep water, which may have prevented settlement of many deep-water species from outside areas and co-existence of species sharing similar ecological niches. The species in the Sulu Sea showed discrete vertical distribution patterns according to the species or species groups, despite the essential absence of vertical gradients of temperature and salinity in the mesopelagic zone. The species pairs that showed similar vertical distributions in the Sulu Sea showed marked differences in their prosome length and/or in the morphology of the 'button setae' and the mandible blade. The species successfully inhabiting the Sulu Sea may have expanded their range into the deep waters, and vertical segregation and food-resource partitioning may be among the major factors allowing the observed coexistence of these congeneric species.

Matsuura, Hiroyuki; Nishida, Shuhei; Nishikawa, Jun



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

NASA Astrophysics Data System (ADS)

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

David, Valérie; Sautour, Benoît; Chardy, Pierre



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

NASA Astrophysics Data System (ADS)

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

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



Redescription of the poorly known planktonic copepod Pontellopsis lubbockii (Giesbrecht, 1889) (Pontellidae) from the Eastern Tropical Pacific with a key to species  

PubMed Central

Abstract During a survey of the epipelagic zooplankton carried out off the coast of the Mexican states of Jalisco and Colima, in the Eastern Tropical Pacific, female and male specimens of the poorly known calanoid copepod Pontellopsis lubbockii (Giesbrecht, 1889) were collected. Because previous descriptions and illustrations are largely incomplete and have caused some taxonomical confusion, this species is fully redescribed from specimens from the Mexican Pacific. The species has some characters that have been overlooked, but those related to the female genital double-somite are the most striking, it has two conical dorsal protuberances and a long ventral spiniform process unique of this species. The mouthparts of this species have not been hitherto described and figured, the flexible terminal setae of legs 3 and 4 is noteworthy. The male general morphology agrees in general with previous data, but new details of the leg 5 and geniculate antennule are added. Its mouthparts, with strong, serrate setae on the maxillae and maxillules, and a strong mandibular edge, suggest that this is a predator form. A dichotomous key for the identification of males and females of the species of Pontellopsis known from the Eastern Tropical Pacific is included.

Suarez-Morales, Eduardo; Kozak, Eva



A novel yellowish-green fluorescent protein from the marine copepod, Chiridius poppei, and its use as a reporter protein in HeLa cells.  


A crustacean gene, encoding for a new class of GFP-like protein, has been isolated from a cDNA library of the deep-sea (benthic) copepod crustacean, Chiridius poppei, by expression cloning. The cDNA library was constructed in a pBluescript II vector and screened using a non-UV transilluminator, obtaining a positive clone. The clone consisted of a 781-bp fragment of cDNA with a 660-bp open reading frame, which encoded for a 219-amino acid polypeptide with a calculated molecular mass of 24.7 kDa. The protein was overexpressed in Escherichia coli, purified to homogeneity by anion-exchange and size-exclusion chromatographies. The protein, CpYGFP, had excitation and emission maxima at 507 and 517 nm, respectively. CpYGFP existed as a dimer in solution and could be expressed either alone or as a fusion protein in HeLa cells. Dual labeling experiments carried out with CpYGFP-actin and DsRed2-Nuc demonstrated the usefulness of CpYGFP as a reporter in the subcellular localization of actin. PMID:16481130

Masuda, Hiromi; Takenaka, Yasuhiro; Yamaguchi, Atsushi; Nishikawa, Satoshi; Mizuno, Hiroshi



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

NASA Astrophysics Data System (ADS)

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

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



Acute waterborne copper toxicity to the euryhaline copepod Acartia tonsa at different salinities: influence of natural freshwater and marine dissolved organic matter.  


The influence of natural dissolved organic matter (DOM) on acute waterborne Cu toxicity was evaluated in the euryhaline copepod Acartia tonsa at 3 different water salinities. Three sources of freshwater DOM (extracted by reverse osmosis) and 2 sources of marine DOM (extracted using a solid-phase technique) were used. Artificial salt water was used to prepare the experimental media. Different combinations of Cu concentrations and DOM sources and concentrations were tested at salinities of 5, 15, and 30 ppt. Toxicity data (48-h median lethal concentration [LC50] values) were calculated based on dissolved Cu concentrations. In a broad view, data showed that increasing salinity was protective against the acute waterborne Cu toxicity. In general, Cu toxicity was also lower in the presence than in the absence of DOM. Toxicity (48-h LC50) values from all treatments at the same salinity showed a positive linear relationship with the dissolved organic carbon (DOC). Thus, the protective effect of DOM against the acute Cu toxicity seems to be dependent mainly on the DOM concentration. However, it seems also to be dependent to some extent on the source of DOM used. In summary, findings reported in the present study clearly indicate that both salinity and DOM (source and concentration) should be taken into account in the development of an estuarine version of the biotic ligand model. PMID:23427042

Monteiro, Sandra Carvalho Rodrigues; Pinho, Grasiela Lopes Leães; Hoffmann, Karine; Barcarolli, Indianara Fernanda; Bianchini, Adalto



Effects of formalin preservation on stable carbon and nitrogen isotope signatures in Calanoid copepods: implications for the use of Continuous Plankton Recorder Survey samples in stable isotope analyses.  


Preserved and archived organic material offers huge potential for the conduct of retrospective and long-term historical ecosystem reconstructions using stable isotope analyses, but because of isotopic exchange with preservatives the obtained values require validation. The Continuous Plankton Recorder (CPR) Survey is the most extensive long-term monitoring program for plankton communities worldwide and has utilised ships of opportunity to collect samples since 1931. To keep the samples intact for subsequent analysis, they are collected and preserved in formalin; however, previous studies have found that this may alter stable carbon and nitrogen isotope ratios in zooplankton. A maximum ~0.9‰ increase of ?(15) N and a time dependent maximum ~1.0‰ decrease of ?(13) C were observed when the copepod, Calanus helgolandicus, was experimentally exposed to two formalin preservatives for 12 months. Applying specific correction factors to ?(15) N and ?(13) C values for similarly preserved Calanoid species collected by the CPR Survey within 12 months of analysis may be appropriate to enable their use in stable isotope studies. The isotope values of samples stored frozen did not differ significantly from those of controls. Although the impact of formalin preservation was relatively small in this and other studies of marine zooplankton, changes in isotope signatures are not consistent across taxa, especially for ?(15) N, indicating that species-specific studies may be required. PMID:21638354

Bicknell, Anthony W J; Campbell, Maria; Knight, Mairi E; Bilton, David T; Newton, Jason; Votier, Stephen C



Seasonal variation in fatty acid composition of seston and the copepod Calanus sinicus (Brodsky, 1962) in Jiaozhou Bay and its trophic implications  

NASA Astrophysics Data System (ADS)

The fatty acid compositions of seston and Calanus sinicus were investigated to study trophic relationships in Jiaozhou Bay. Principal component analysis was carried out to ordinate the fatty acid patterns of seston in stations and months. The results showed that diatoms were most abundant in the phytoplankton at station A5 (located in the northwest of the bay: 36°9'N, 120°20'E) and least abundant at station D7 (located outside of the bay: 35°59'N, 120°26'E). By contrast, dinoflagellates were most abundant at station D7 and least abundant at station A5. According to the annual variations of 16:1?7 and 18:4?3/16:1?7, diatoms flourished mainly in spring and summer, while dinoflagellates bloomed exclusively in summer. A distinctive feature of the fatty acid composition of C. sinicus was the prevalence of 20:5?3 and 22:6?3. The higher content of 16:1?7 over 18:4?3 in females indicated that diatoms contributed more than dinoflagellates to the diet of C. sinicus. The feeding intensity of C. sinicus on diatoms was higher in spring and autumn than in other seasons. The herbivorous indicators 20:1 and 22:1 were comparatively low, suggesting that besides phytoplankton, C. sinicus might feed on a wider range of particles including organic detritus, bacteria and small copepods.

Liu, Mengtan; Li, Chaolun; Sun, Song



Amplified fragment length polymorphism analysis of the mesopelagic copepod Disseta palumbii in the equatorial western Pacific and adjacent waters: Role of marginal seas in the genetic isolation of mesopelagic animals  

NASA Astrophysics Data System (ADS)

The genetic structure of the mesopelagic copepod Disseta palumbii in the equatorial western Pacific and adjacent marginal seas was examined by the amplified fragment length polymorphism (AFLP) analysis of 34 individuals from the Philippine Sea (10 individuals), Celebes Sea (10), Sulu Sea (4), and South China Sea (10). Phylogenetic analysis of the scored AFLP results showed two major clades (clades A and B) with six and sixteen alleles that were uniquely observed in clade A and B, respectively. Within clade B, subtle but significant genetic differences between individuals in the Sulu and those in the other seas were also observed, suggesting a role for semienclosed marginal seas in allopatric speciation.

Machida, Ryuji J.; Nishida, Shuhei



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

SciTech Connect

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

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



Diel vertical behavior of Copepoda community (naupliar, copepodites and adults) at the boundary of a temperate estuary and coastal waters  

NASA Astrophysics Data System (ADS)

Despite a growing interest in diel vertical migration as a research topic, there are few studies in southern European marine coastal systems. This study determined the main structuring hydrological and physical factors at different temporal scales in copepod assemblage distribution patterns. Seasonal, tidal, lunar and diel vertical migrations accomplished by horizontal movements were examined on the main copepod fraction of the Mondego estuary, Portugal. Seasonal samples were conducted hourly at the mouth of the estuary, during diel cycles (25 h), both over neap and spring tides, at the bottom and surface, using a 63 ?m and 335 ?m mesh size nets. Simultaneously, four sites inside the estuary were sampled during flood tide to evaluate and compare copepods species' distribution along the estuary. Species life cycles were also categorized. Spring-spring tide best expresses the stable part of copepod-environment dynamics. Acartia tonsa and Oithona nana were distributed mainly at the bottom during ebb tides. A clear resident estuarine performance was noticeable in O. nana proving the estuarine preferences of the species. Neritic species showed preferences by saline waters, whereas the resident species were found mainly at estuarine areas. Copepodites stages showed a similar distribution pattern as estuarine species, avoiding leaving the estuary. In contrast nauplii and Oithona plumifera showed higher densities at surface flood tides. Indeed, vertical migrations accomplished by horizontal movements were mainly influenced by depth and tidal cycles, whereas day and night were not ecologically significant.

Gonçalves, A. M. M.; Pardal, M. A.; Marques, S. C.; Mendes, S.; Fernández-Gómez, M. J.; Galindo-Villardón, M. P.; Azeiteiro, U. M.



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

USGS Publications Warehouse

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

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



Horizontal transport of the calanoid copepod Neocalanus in the North Pacific: The influences of the current system and the life history  

NASA Astrophysics Data System (ADS)

The horizontal transport of calanoid copepod Neocalanus flemingeri, N. plumchrus and N. cristatus in the subarctic North Pacific has been investigated by particle tracking experiments using an ocean circulation model. In our physical numerical model, the current and frontal systems in the subarctic Pacific are reproduced realistically, and fine-resolved (not smoothed) and vertically sheared western boundary currents in the model enable us to assess the differences in horizontal transports among Neocalanus species. In the experiments, seasonal vertical migration and life cycle of Neocalanus species is included, and this attempt is a novel approach in examining the transports of the zooplanktons. The maximal depths of the vertical migrations and the lengths of the surface and mesopelagic dwelling duration are the essential factors in characterizing the trajectory of the horizontal transport. Both small and large forms of N. flemingeri (hereafter NF-SF and NF-LF) whose mesopelagic-inhabited depths are the shallowest among the three Neocalanus species are transported to more distant regions from initial positions compared with the others. The longest transport distance is over 5000 km for NF-SF. On the other hand, the transport distance of the deepest inhabitant N. cristatus (hereafter NC) is the shortest. The differences in the transport distance are due to the current speed of the western boundary currents at the inhabited depth at which they spend most of their lifetime (ca. 3/4 of their lifetime). More than 82% of NF-LF that originated from the Okhotsk Sea completes its life cycle in the Okhotsk Sea, and all the animals out to the Pacific are transported to the south of the subarctic front where their survivals are unexpected due to high temperatures. This is consistent with the observed limited distribution of NF-LF in the Okhotsk Sea and its surrounding waters. Geographical genetic variations of Neocalanus species are reported as very low. This implies frequent genetic exchange all over the Pacific and its adjacent seas. Being consistent with the above, the present study suggests that the trans-Pacific transport of Neocalanus species can be accomplished within a few generations.

Tatebe, Hiroaki; Yasuda, Ichiro; Saito, Hiroaki; Shimizu, Yugo



Metazooplankton communities in the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia): spatiotemporal variations and trophic relationships.  


Metazooplankton abundance, biomass (<80 ?m, 200-500 ?m and >500 ?m) and community structure in the Ahe atoll were studied together with their relationships with environmental factors (temperature, salinity, wind) and trophic factors (phytoplankton, bacteria, heterotrophic nanoflagellates (HNF) and ciliates) during three periods in 2008-2009. Meroplankton, mainly bivalve and gastropod larvae, was dominant. Holoplankton was dominated by copepods, the main species being Oithona spp., Paracalanus parvus, Clausocalanus spp., Corycaeus spp., Acartia fossae and Undinula vulgaris. The results suggest a clear wind influence on the structure and horizontal distribution of the zooplankton communities. The metazooplankton appeared to be controlled mainly by food resources, suggesting a bottom-up control. The low nanophytoplankton biomass in contrast to the high abundance of picophytoplankton, HNF and nano-particle grazers (mainly Oithona spp., Paracalanus and bivalve larvae) highlighted the importance of the microbial loop in the food web. PMID:22330075

Pagano, Marc; Sagarra, Pascual-Boi; Champalbert, Gisèle; Bouvy, Marc; Dupuy, Christine; Thomas, Yoann; Charpy, Loïc



Zooplankton abundance in relation to state and type of intrusions onto the southeastern United States shelf during summer  

SciTech Connect

The vertical distribution of zooplankton on the continental shelf of northeastern Florida was determined in and around upwelling events and related to concentrations of particulate matter. Doliolida and the cladoceran Penilia avirostris were significantly more abundant in upwelled water < 22/sup 0/C and the cyclopoid genus Oncaea more abundant at warmer temperatures. The abundance of doliolida, Oithona and Oncaea in intrusions and the thermocline was significantly higher in older than in recently upwelled waters. The vertical sequences of the abundance of zooplankton and particulate matter (2-114 ESD) were identical. Zooplankton maxima co-occurred primarily with maxima in phytoplankton biomass (chlorophyll a) and only partly with primary productivity. 27 references, 16 figures, 6 tables.

Paffenhoefer, G.A.; Wester, B.T.; Nicholas, W.D.



Distribution and diets of larval and juvenile fishes: Influence of salinity gradient and turbidity maximum in a temperate estuary in upper Ariake Bay, Japan  

NASA Astrophysics Data System (ADS)

We investigated the fish assemblage and distribution, diversity, and diets in relation to copepod prey communities along the Chikugo estuarine gradient in the Ariake Bay, Japan. Larval and juvenile fish samples, ambient copepod samples were collected and major hydrographic parameters were recorded at seven selected sampling stations (salinity range: 0.4 28.8 psu) during four sampling cruises in spring 2001. A zone of estuarine turbidity maximum (ETM) was identified in the upper part of the estuary which was characterized by low salinity. Two different fish and copepod communities based on the spatial distribution patterns were identified: the oligohaline community in the upper estuary, which was associated with the ETM; and the euryhaline community in the lower estuary, downstream of the ETM. The oligohaline fish community was composed of Acanthogobius flavimanus, Acanthogobius hasta, Coilia nasus, Neosalanx reganius, and Trachidermus fasciatus while the euryhaline community was composed of Engraulis japonicus and Sebastes inermis. Lateolabrax japonicus was distributed over wide spatial areas. Sinocalanus sinensis was the single dominant member of the oligohaline copepod community while the euryhaline community was dominated by Oithona davisae, Acartia omorii and Paracalanus parvus. Strong dietary relationships were identified between fishes and copepods in the same community. ETM appears to have significant influence on the distribution and abundance of the oligohaline copepod S. sinensis and this prey copepod appears to have strong influence on the fishes in the oligohaline regions. Most of the fishes were distributed in the low saline upper estuary where they foraged on the single dominant copepod S. sinensis which contributes the majority of the copepod standing biomass of the estuary and thus appear to support nursery for fishes. It was concluded that the ETM-based copepod S. sinensis plays a key role in survival and distribution of larval and juvenile fishes in Chikugo estuary.

Islam, Shahidul; Hibino, Manabu; Tanaka, Masaru



8-Oxoguanine DNA glycosylase 1 (OGG1) from the copepod Tigriopus japonicus: molecular characterization and its expression in response to UV-B and heavy metals.  


8-Oxoguanine DNA glycosylase 1 (EC is encoded by OGG1 gene and plays a key role in removing 8-oxo-7,8-dihydroguanine (8-oxoG) base in DNA lesion by reactive oxygen species (ROS). To identify and characterize OGG1 gene (TJ-OGG1) in the copepod Tigriopus japonicus, the full-length cDNA sequence, genomic structure, and promoter region was analyzed. In addition, to investigate transcriptional change of TJ-OGG1 mRNA under oxidative stress conditions, T. japonicus were exposed to environmental oxidative inducers, H(2)O(2), UV-B, and heavy metals (Cd, Cu, and Zn), respectively. The full-length cDNA of TJ-OGG1 gene was 1708 bp in length, encoding 343 amino acid residues. The deduced amino acid sequences of TJ-OGG1 showed a 56% similarity with human. Two conserved motifs (HhH and PVD loop) and two conserved residues (lysine and aspartic acid) in active sites were also observed. TJ-OGG1 genome structure contained six exons and five introns and putative transcription factor binding sites such as Nrf-2, p53, ERE-half sites, and XRE were detected on the promoter region. TJ-OGG1 mRNA level was increased at approximately three-fold (P<0.05) at 1mM and approximately 4-fold (P<0.01) at 10mM of H(2)O(2), respectively. UV-B enhanced the expression of TJ-OGG1 mRNA at 15kJ/m(2) (P<0.05) and more (P<0.001). In a time-course experiment, TJ-OGG1 gene was highly transcribed within 12h after exposure of 10 kJ/m(2) (P<0.01) and 20 kJ/m(2) (P<0.001). The expression of TJ-OGG1 mRNA after exposure to Cu and Cd for 96 h was significantly up-regulated at 0.1 ?g/L and then remarkably reduced in a dose-dependent manner. Their transcript levels did not change at low dose (0.1 and 1 ?g/L) but were dose-dependently down-regulated at high dose (10 and 100 ?g/L). These findings suggest that H(2)O(2), UV-B, and heavy metals induce oxidative stress and generate oxidatively damaged DNA. Consequently, the enhanced TJ-OGG1 gene expression would be associated with active involvement of TJ-OGG1 gene in DNA repair process as a cellular protection mechanism. This is the first report on the cloning and characterization of OGG1 gene in aquatic animals. This study is helpful for a better understanding of the molecular mechanisms of cellular protection against various environmental oxidative stress inducers such as UV-B and heavy metals in aquatic invertebrates. PMID:21983336

Kim, Bo-Mi; Rhee, Jae-Sung; Seo, Jung Soo; Kim, Il-Chan; Lee, Young-Mi; Lee, Jae-Seong



Sequence, biochemical characteristics and expression of a novel Sigma-class of glutathione S-transferase from the intertidal copepod, Tigriopus japonicus with a possible role in antioxidant defense.  


Glutathione S-transferases (GSTs) play a major role in detoxification of xenobiotics and antioxidant defense. Here we report full-length cDNA sequence of a novel Sigma-class of GST (GST-S) from the intertidal copepod Tigriopus japonicus. The full sequence was of 1,136 bp in length containing an open reading frame (ORF) of 651 bp that encoded 217 amino acid residues. The recombinant Tigriopus GST-S was highly expressed in transformed Escherichia coli. Kinetic properties and effects of pH, temperature and chemical inhibitors on Tigriopus GST-S were also studied. The expression of GST-S was studied using real-time RT-PCR in response to exposure to two oxidative stresses-inducing agents, viz., hydrogen peroxide (H(2)O(2)) and heavy metals (copper, manganese). It was observed that H(2)O(2) (2mM) exposure down-regulated its expression at the initial stage but there was recovery and up-regulation shortly afterwards. In case of heavy metal exposure there was concentration-dependent increase in Tigriopus GST-S gene expression up to 24h. These results suggest that Tigriopus GST-S expression is modulated by prooxidant chemicals and it may play a role against oxidative stress. A majority of other GST isoforms is known to play an important role in antioxidant defense. This study provides a preliminary insight into the possible antioxidant role for Sigma-class of GST in T. japonicus. PMID:17659322

Lee, Young-Mi; Lee, Kyun-Woo; Park, Hyun; Park, Heum Gi; Raisuddin, Sheikh; Ahn, In-Young; Lee, Jae-Seong



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

NASA Astrophysics Data System (ADS)

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

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



Spines on diatoms:Do copepods care?  

Microsoft Academic Search

CaZanus$nmarchicus was allowed to feed on two forms of the diatom Thalassiosira weiss- flogii (=T. fluviatilis): normal cells, which are spinose, and cells which did not have spines. Filtration rates of Calanus on the spinose form were on average 1.7 times higher than on cells with no spines. The diatom Thalassiosira weissflogii (Grunow) G. Fryxell and Hasle Comb. nov. (=Thalassiosira




Bioaccumulation of polonium-210 in marine copepods  

Microsoft Academic Search

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

Gillian M. Stewart; Nicholas S. Fisher



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

NASA Astrophysics Data System (ADS)

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

Kumar, Ram; Ramakrishna Rao, T.



Planktivory in the changing Lake Huron zooplankton community: Bythotrephes consumption exceeds that of Mysis and fish  

USGS Publications Warehouse

Oligotrophic lakes are generally dominated by calanoid copepods because of their competitive advantage over cladocerans at low prey densities. Planktivory also can alter zooplankton community structure. We sought to understand the role of planktivory in driving recent changes to the zooplankton community of Lake Huron, a large oligotrophic lake on the border of Canada and the United States. We tested the hypothesis that excessive predation by fish (rainbow smelt Osmerus mordax, bloater Coregonus hoyi) and invertebrates (Mysis relicta, Bythotrephes longimanus) had driven observed declines in cladoceran and cyclopoid copepod biomass between 2002 and 2007. We used a field sampling and bioenergetics modelling approach to generate estimates of daily consumption by planktivores at two 91-m depth sites in northern Lake Huron, U.S.A., for each month, May-October 2007. Daily consumption was compared to daily zooplankton production. Bythotrephes was the dominant planktivore and estimated to have eaten 78% of all zooplankton consumed. Bythotrephes consumption exceeded total zooplankton production between July and October. Mysis consumed 19% of all the zooplankton consumed and exceeded zooplankton production in October. Consumption by fish was relatively unimportant - eating only 3% of all zooplankton consumed. Because Bythotrephes was so important, we explored other consumption estimation methods that predict lower Bythotrephes consumption. Under this scenario, Mysis was the most important planktivore, and Bythotrephes consumption exceeded zooplankton production only in August. Our results provide no support for the hypothesis that excessive fish consumption directly contributed to the decline of cladocerans and cyclopoid copepods in Lake Huron. Rather, they highlight the importance of invertebrate planktivores in structuring zooplankton communities, especially for those foods webs that have both Bythotrephes and Mysis. Together, these species occupy the epi-, meta- and hypolimnion, leaving limited refuge for zooplankton prey. Published 2011. This article is a US Government work and is in the public domain in the USA.

Bunnell, D. B.; Davis, B. M.; Warner, D. M.; Chriscinske, M. A.; Roseman, E. F.



The Bag-Sampler: A Simple Device for Collecting Zooplankton in Shallow Vegetated Ponds  

NASA Astrophysics Data System (ADS)

Zooplankton in temporary ponds is often collected with gear originally designed for lakes, and mostly unsuitable for sampling shallow habitats. We describe a new simple and inexpensive device for sampling zooplankton in very shallow, vegetated temporary ponds. We tested the sampling efficiency by comparing species composition and density of cyclopoid copepods, an important component of the zooplankton, by sampling with both the new bag sampler and a plastic beaker frequently employed for collections of zooplankton in small waterbodies. With the bag sampler we collected a larger number of species and higher densities of copepods due to its higher efficiency in vegetated areas and near the sediment. The beaker appeared to sample almost only the water surface. The samples collected with the bag sampler revealed a distinct distribution of copepod life cycle stages in a shallow pond, which differed between depths and microhabitats. Additional advantages of the bag sampler are its small size and weight, and the possibility of fast exchange of sample bags between sample locations, thus preventing accidental faunal exchange between sample locations. We conclude that the bag sampler is a device especially useful for sampling zooplankton of shallow ponds and wetlands rich in vegetation, for diversity studies as well as for quantitative sampling.

Frisch, Dagmar; Wohltmann, Andreas



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

SciTech Connect

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

Shuman, J.R.



Seasonal cycles of zooplankton from San Francisco Bay  

USGS Publications Warehouse

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

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



Population dynamics and parasitation of planktonic and epibenthic crustaceans in the Baltic Schlei fjord  

NASA Astrophysics Data System (ADS)

The planktonic and epibenthic crustacean fauna from two sites of the brackish Schlei fjord, Northern Germany, was investigated over a six-month period. Calanoid and cyclopoid copepods were more abundant in lower salinities, whereas, benthic decapods, isopods and amphipods prevailed in the site of higher salinity. Cestodan larvae were found only in spring which may be due to the timing of the respective life-cycles. Parasites of benthic crustaceans, mostly digenean metacercariae but also cestodans, acanthocephalans and nematodes, appeared from spring to late summer. Decreasing salinities caused lower intensities of the most abundant parasite, Maritrema subdolum; only the true brackish-water species among the hosts were more heavily infested than those found in higher salinities. The correlation of parasite size and host size at infestation became apparent. Therefore, Crangon crangon is an optimal host for the large Podocotyle atomon metacercariae. Coevolutive trends between some hosts and parasites are made evident.

Gollasch, S.; Zander, C. D.



A new species of Sabellacheres M. Sars, 1862 (Copepoda: Gastrodelphyidae) from a deep-water benthic polychaete in Antarctic waters, with a key to the species of the genus.  


Specimens of a deep-living sabellid polychaete of the genus Perkinsiana Knight-Jones dredged in Antarctic waters were found to be parasitised by an undescribed species of the cyclopoid copepod genus Sabellacheres M. Sars, 1862. Specimens of both sexes were studied using light microscopy and SEM, and compared with its congeners. The new species, Sabellacheres antarcticus n. sp., can be distinguished from its congeners by the shape and proportions of the body and brood-pouch, its 4-segmented antennae, the shape and length of the distal process of the second antennular segment, the position of leg 3, and the structure of the male maxilliped. This is only the second record of a species of this genus from the southern hemisphere. The new species was found on a single host species, as is typical for most species of Sabellacheres. A key for the identification of both sexes of the species of Sabellacheres is included. PMID:22890381

Suárez-Morales, Eduardo; Boxshall, Geoffrey A



Micro- and mesozooplankton in Southwest Greenland waters in relation to environmental factors  

NASA Astrophysics Data System (ADS)

Plankton samples and oceanographic data were obtained during transect studies across fishing banks over the Southwest Greenland shelf in June 1999, May, and July 2000. The study gives a detailed description of micro- and mesozooplankton distributions and community structures during spring bloom and post bloom periods. Plankton distributions were related to the physical environment described by a hydrodynamic ocean circulation model. More than 30 species and a larger number of taxonomic categories were identified in the zooplankton samples. Large copepodites of Calanus finmarchicus, Calanus glacialis, and Calanus hyperboreus generally dominated the micro- and mesozooplankton biomass, with Pseudocalanus spp., Metridia longa, and Oithona spp. comprising most of the remaining biomass. By number, bivalves larvae and relatively large copepod nauplii (>200 ?m) dominated the zooplankton community (>50 ?m) in May, whereas smaller copepod nauplii (<200 ?m) were dominating in June and July. In May during a spring bloom period, diatoms, Thalassiosira spp. and Chaetoceros spp., generally dominated the biomass of the plankton community of the upper 100 m followed by heterotrophic flagellates, copepods, other invertebrates, and ciliates. Conversely in June (and July) during post bloom, large copepods were dominating. Hydrodynamic model simulations of ocean currents and trajectories of potential plankton transports showed differences in potential advection of plankton across shelf banks. The circulation around the banks seems to create retention areas entrapping plankton for periods. Model simulations predict that upwelling occurs west of the shelf banks and to a lesser extent in the deep channels separating the banks. This upwelling, caused by wind and tidal motions, probably increases productivity and carbon cycling over the shelf areas.

Pedersen, Søren A.; Ribergaard, Mads H.; Simonsen, Claus S.



Trophic accumulation of PSP toxins in zooplankton during Alexandrium fundyense blooms in Casco Bay, Gulf of Maine, April-June 1998. II. . Zooplankton abundance and size-fractionated community composition  

NASA Astrophysics Data System (ADS)

During spring blooms of the toxic dinoflagellate Alexandrium fundyense in Casco Bay, Maine in 1998, we investigated vectorial intoxication of various zooplankton size fractions with PSP toxins, including zooplankton community composition from quantitative zooplankton samples (>102 ?m), as well as zooplankton composition in relation to toxin levels in various size fractions (20-64, 64-100, 100-200, 200-500, >500 ?m). Zooplankton abundance in 102 ?m mesh samples was low (most values<10,000 animals m -3) from early April through early May, but increased to maxima in mid-June (cruise mean=121,500 animals m -3). Quantitative zooplankton samples (>102 ?m) were dominated by copepod nauplii, and Oithona similis copepodites and adults at most locations except for those furthest inshore. At these inshore locations, Acartia hudsonica copepodites and adults were usually dominant. Larger copepods such as Calanus finmarchicus, Centropages typicus, and Pseudocalanus spp. were found primarily offshore, and at much lower abundances than O. similis. Rotifers, mainly present from late April to late May, were most abundant inshore. The marine cladoceran Evadne nordmani was sporadically abundant, particularly in mid-June. Microplankton in 20-64 ?m size fractions was generally dominated by A. fundyense, non-toxic dinoflagellates, and tintinnids. Microplankton in 64-100 ?m size fractions was generally dominated by larger non-toxic dinoflagellates, tintinnids, aloricate ciliates, and copepod nauplii, and in early May, rotifers. Some samples (23%) in the 64-100 ?m size fractions contained abundant cells of A. fundyense, presumably due to sieve clogging, but most did not contain A. fundyense cells. This suggests that PSP toxin levels in those samples were due to vectorial intoxication of microzooplankters such as heterotrophic dinoflagellates, tintinnids, aloricate ciliates, rotifers, and copepod nauplii via feeding on A. fundyense cells. Dominant taxa in zooplankton fractions varied in size. Samples in the 100-200 ?m size fraction were overwhelmingly dominated in most cases by copepod nauplii and small copepodites of O. similis, and during late May, rotifers. Samples in the 200-500 ?m size fraction contained fewer copepod nauplii, but progressively more copepodites and adults of O. similis, particularly at offshore locations. At the most inshore stations, copepodites and adults of A. hudsonica were usual dominants. There were few copepod nauplii or O. similis in the>500 ?m size fraction, which was usually dominated by copepodites and adults of C. finmarchicus, C. typicus, and Pseudocalanus spp. at offshore locations, and A. hudsonica inshore. Most of the higher PSP toxin concentrations were found in the larger zooplankton size fractions that were dominated by larger copepods such as C. finmarchicus and C. typicus. In contrast to our earlier findings, elevated toxin levels were also measured in numerous samples from smaller zooplankton size fractions, dominated by heterotrophic dinoflagellates, tintinnids and aloricate ciliates, rotifers, copepod nauplii, and smaller copepods such as O. similis and, at the most inshore locations, A. hudsonica. Thus, our data suggest that ingested PSP toxins are widespread throughout the zooplankton grazing community, and that potential vectors for intoxication of zooplankton assemblages include heterotrophic dinoflagellates, rotifers, protozoans, copepod nauplii, and small copepods.

Turner, Jefferson T.; Doucette, Gregory J.; Keafer, Bruce A.; Anderson, Donald M.



Mesozooplankton community response during the SERIES iron enrichment experiment in the subarctic NE Pacific  

NASA Astrophysics Data System (ADS)

The response of the mesozooplankton community was examined during the development and early decline of the Subarctic Ecosystem Response to Iron Enrichment Study diatom bloom in July 2002. No significant changes in species composition were observed during this period. In terms of abundance, the community was dominated by small copepods ( Oithona spp. and Pseudocalanus spp.). The abundance of large herbivorous calanoids of the genus Neocalanus ( N. plumchrus, N. cristatus and N. flemingeri) was already low at the start of the experiment as most of these animals had already descended to their overwintering depth. Mesozooplankton biomass was dominated by the calanoids Eucalanus bungii, Calanus pacificus, Metridia pacifica and, to a lesser extent, late stage copepodites (CIV, CV) of Neocalanus spp. In general, the abundance of all copepod species tended to increase inside the patch (relative to conditions outside the patch) during the experiment. However, mean species-specific abundances were not significantly different inside and outside of the patch, except for a significant increase of E. bungii ( p<0.05) that occurred between Days 10 and 13 inside the iron-fertilized patch. By Day 8, most of the E. bungii population had shifted its vertical distribution into the surface mixed layer. We hypothesize that a wind event displacing the surface mixed layer coincident with continued immigration from below the thermocline facilitated this increase in abundance. Here we address this higher trophic level response to pulsed primary production in terms of potential mechanisms and their potential impact on the diatom bloom.

Sastri, Akash R.; Dower, John F.



Discriminating zooplankton assemblages in neritic and oceanic waters: a case for the northeast coast of India, Bay of Bengal.  


Zooplankton species distribution and abundance data at 17 locations in the inshore (10-30 m), shelf (50-200 m) and oceanic (2,500-2,800 m) regions off northeast India (Bay of Bengal) during January 1999-April 2001 revealed 112 taxa represented by 30 divergent groups. Copepods (58 species) dominated (87%) the population numerically. In general zooplankton diversity (Margalef richness d, Shannon-Wiener H', Pielou's evenness J') increased in the direction of the open sea relative to coastal locations with a concomitant decrease both in abundance (ind m(-3)) and biomass (dry mass m(-3)). Based on multivariate analyses, it was possible to distinguish the zooplankton community into different assemblages according to their location (e.g., inshore, shelf, oceanic) and seasonality. While Acrocalanus sp., Oithona sp., Corycaeus danae, Euterpina acutifrons, Paracalanus sp., and Acartia sp. were found characterizing the coastal locations, Oncaea venusta was the discriminating species for shelf waters. In oceanic areas, there was a clear dominance of Labidocera sp., Candacia sp., Euchaeta rimana, Centropages calaninus, Copilia mirabilis and Corycella gibbula. The investigations revealed that changes in zooplankton community structure across water bodies could be associated with differing salinity. During November 1999 (post-monsoon), when salinity in the coastal waters was relatively low (26-28.9 PSU), the zooplankton community consisted of mainly Acrocalanus sp., Salpa, Corycaeus danae, Oikopleura sp., Acartia sp., Evadne tergestina, and Creseis sp. In January 2000 (salinity 32.4-34.1), additionally Corycella gibbula, Labidocera sp., Centropages sp., Microsetella sp., Euterpina acutifrons, Canthocalanus pauper, and Oncaea venusta represented the population discriminating the assemblage from others. In May 2000 (pre-monsoon) when salinity was highest (34.7-35.3), Oithona sp., Paracalanus sp., and Acrocalanus gibber were found important. Chaetognaths formed a distinct group during this period. Results presented during this investigation are considered significant since no previous studies exist for this locale drawing comparisons of the kind made during this study between coastal and oceanic situations. PMID:16125769

Rakhesh, M; Raman, A V; Sudarsan, D



Heterochromatin endoreduplication prior to gametogenesis and chromatin diminution during early embryogenesis in Mesocyclops edax (Copepoda: Crustacea).  


The segregation of progenitor somatic cells from those of the primordial germ cells that sequester and retain elevated levels of DNA during subsequent developmental events, poses an interesting, alternative pathway of chromosome behavior during the reproductive cycle of certain species of cyclopoid copepods and several other organisms. Separation of maternal and paternal chromosome sets during very early cleavages (gonomery) is often a feature following marked elevations of DNA levels in germ cells for some of these species. Here, we report on the accumulation of large amounts of DNA in germ line nuclei of both female and male juveniles and adults of a freshwater copepod, Mesocyclops edax (Forbes, 1890). We also report the robust uptake of 3H-thymidine by germ cells prior to gametogenesis in this species. By using cytophotometric analysis of the DNA levels in both germ line cells and somatic cells from the same specimens we demonstrate that germ cell nuclei accumulate high levels of DNA prior to the onset of gametogenesis. These elevated amounts coincide with the levels of heterochromatic DNA discarded during chromatin diminution. A new model is proposed of major cytological events accompanying the process of chromatin diminution in M. edax. PMID:17932949

Rasch, Ellen M; Wyngaard, Grace A; Connelly, Barbara A



Diversity and Seasonality of Bioluminescent Vibrio cholerae Populations in Chesapeake Bay?  

PubMed Central

Association of luminescence with phenotypic and genotypic traits and with environmental parameters was determined for 278 strains of Vibrio cholerae isolated from the Chesapeake Bay during 1998 to 2000. Three clusters of luminescent strains (A, B, and C) and two nonluminescent clusters (X and Y) were identified among 180 clonal types. V. cholerae O1 strains isolated during pandemics and endemic cholera in the Ganges Delta were related to cluster Y. Heat-stable enterotoxin (encoded by stn) and the membrane protein associated with bile resistance (encoded by ompU) were found to be linked to luminescence in strains of cluster A. Succession from nonluminescent to luminescent populations of V. cholerae occurred during spring to midsummer. Occurrence of cluster A strains in water with neutral pH was contrasted with that of cluster Y strains in water with a pH of >8. Cluster A was found to be associated with a specific calanoid population cooccurring with cyclopoids. Cluster B was related to cluster Y, with its maximal prevalence at pH 8. Occurrence of cluster B strains was more frequent with warmer water temperatures and negatively correlated with maturity of the copepod community. It is concluded that each cluster of luminescent V. cholerae strains occupies a distinct ecological niche. Since the dynamics of these niche-specific subpopulations are associated with zooplankton community composition, the ecology of luminescent V. cholerae is concluded to be related to its interaction with copepods and related crustacean species.

Zo, Young-Gun; Chokesajjawatee, Nipa; Grim, Christopher; Arakawa, Eiji; Watanabe, Haruo; Colwell, Rita R.



Zooplankton community responses to chlorpyrifos in mesocosms under Mediterranean conditions.  


The effects of chlorpyrifos (organophosphate insecticide) on zooplankton were studied in outdoor experimental tanks (mesocosms) sited in the Mediterranean Region (Madrid, Spain) at two nominal concentrations of chlorpyrifos (0.1 and 1 microg a.s./L applied as Chas 48) and control were used. Five tanks were used as control and the treatments were performed in quintuplicate. A single chlorpyrifos application simulating spray-drift was conducted. The population and community effects were analyzed by means of univariate statistics and through the multivariate principal response curves (PRC) technique. The most affected zooplankton taxa were cladocerans (Daphnia group galeata), copepods (cyclopoids and copepod nauplii) and rotifers (Keratella cochlearis) showing in all the cases significant decreases in abundance at 1 microg chlorpyrifos/L. The calculated NOEC was 0.1 microg/L for these taxa as well as for the community. The zooplankton community was considered to be recovered after 99 days post-application. The results of this experiment were similar to those derived from mesocosm/microcosm studies performed in temperate regions. This indicates that a chlorpyrifos concentration of 0.1 microg chlorpyrifos/L could be the appropriate safe level for zooplankton community in different climatic regions. However, at treatment level of 1.0 microg/L the time required for full recovery of the affected populations (particularly Cladocera) was longer than in the other experiments performed in temperate regions. PMID:17629945

López-Mancisidor, Patricia; Carbonell, Gregoria; Marina, Ana; Fernández, Carlos; Tarazona, José V



Tidal exchange of zooplankton between Lough Hyne and the adjacent coast  

NASA Astrophysics Data System (ADS)

Plankton samples collected in November 2002, February, May and August 2003 were used to examine seasonal variation in tidal exchange of zooplankton biomass, abundance and species composition between Lough Hyne Marine Nature Reserve and the adjacent Atlantic coast. Micro- to mesozooplankton were collected by pump over 24-h sampling periods during spring and neap tides from the narrow channel connecting the semi-enclosed water body to the Atlantic. Sample biomass (dry weight) and total zooplankton abundance peaked in the summer and were lowest in winter, showing a positive relationship with temperature. Zooplankton biomass, total abundance and numbers of holo- and meroplankton revealed import during some diel cycles and export in others. However, the tidal import of these planktonic components was generally dominant, especially during May. The greatest import of numbers of holoplankters and meroplanktonic larvae occurred during May and August, respectively. There was no significant variation in sample biomass between periods of light and dark, but some variation in zooplankton abundance could be explained by this diel periodicity. Significant differences in sample assemblage composition between flood and ebb tide samples were always observed, except during winter neap tides. There was a net import of the copepods Temora longicornis and Oithona helgolandica and the larval stages of Mytilus edulis during spring and summer. Proceraea cornuta and Capitellid trochophores were imported during winter, and a hydrozoan of the genus Obelia during the spring spring tides. Seasonal export from the lough was shown by Pseudopolydora pulchra larvae (autumn and spring), Serpulid trochophores (autumn) and veligers of the bivalve Anomia ephippium (summer). It is suggested that the direction of tidal exchange of meroplanktonic taxa is related to the distribution of the adult populations. Copepod naupliar stages dominated the assemblages except during May spring tides when the copepod Pseudocalanus elongatus made up over 22% of the abundance. The general import of micro- to mesozooplankton may, in part, explain the higher densities of this size-class of zooplankton within the semi-enclosed system of Lough Hyne.

Rawlinson, K. A.; Davenport, J.; Barnes, D. K. A.



Development of the marine planktonic copepod Temora longicornis  

NASA Astrophysics Data System (ADS)

The paper presents an empirical model describing the coefficient of daily exponential growth and weight increment for different developmental periods of Temora longicornis. The quantitative expressions describing the effects of food concentration and temperature on the above parameters were developed. The calculations were made on the basis of experimental data. In the work also obtained the stage duration of specific size-classes of Temora longicornis as a function of food concentration and temperature. Expressions computed here may be used with good precision in mathematical models of pelagic communities.

Dzierzbicka-Glowacka, L.; Lemieszek, A.; Zmijewska, I. M.



Diapause in Calanoid Copepods: within-clutch hatching patterns  

Microsoft Academic Search

Diapause is a major life history feature of many invertebrate organisms. Determining the phenology of diapause is critical for understanding survival and reproductive success of individuals as well as the long-term viability of many populations. The time spent in dormancy by individuals and variability among offspring in the duration of dormancy are two important aspects of invertebrate life histories. Some




Blue Pigment of a Surface-living Oceanic Copepod  

Microsoft Academic Search

THE development of special nets has made it possible to sample specifically the plankton living in the uppermost layers of the sea. Routine sampling with such a net, designed by P. M. David at the National Institute of Oceanography, to fish only in the top 4 in. of the water, has been carried out during the present cruise of the

P. J. Herring



Cultivation of marine copepods for genetic and evolutionary research  

Microsoft Academic Search

Kurzfassung Einige benthische Copepoden eignen sich ausgezeichnet für das Studium genetischer Aspekte evolutiver Vorgänge im Meer. Dazu gehören speziell die Arten der GattungTisbe, weil sie (1) im Labor mit Hilfe einfacher Methoden kultiviert werden können, (2) einen kurzen Entwicklungszyklus haben, (3) eine hohe Vermehrungsrate und (4) oft genetischen Polymorphismus aufweisen. Es hat sich herausgestellt, daß dieser Polymorphismus in einigen Fällen

B. Battaglia



The population genetic consequences of diapause in Eudiaptomus copepods  

Microsoft Academic Search

Prolonged diapause (extended dormancy) is thought to greatly influence evolution in freshwater invertebrates by lengthening generation time, promoting higher levels of dispersal among populations by wind or animal vectors, and increasing effec- tive population size. However, empirical tests of these predictions are relatively rare. Comparative studies can be informative in this regard, if the comparisons involve sym- patric, closely related

Andrew J. Bohonak; Matthew D. Holland; Barbara Santer; Martina Zeller; Colleen M. Kearns; Nelson G. Hairston



Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River  

USGS Publications Warehouse

As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook salmon. Juvenile American shad were abundant and represented over 98% of the trawl catch in late summer. The five major taxa collected in zooplankton tows were Bosmina longirostris, Daphnia, cyclopoid cope-pods, rotifers, and calanoid copepods. We evaluated total crustacean zooplankton abundance and Daphnia biomass in relation to water temperature, flow, depth, diel period, and cross-sectional location using multiple regression. Differences in zooplankton abundance were largely due to differences in water temperature and flow. Spatial variation in total zooplankton abundance was observed in McNary Reservoir, but not in John Day Reservoir. Juvenile American shad generally fed on numerically abundant prey, despite being less preferred than larger bodied zooplankton. A decrease in cladoceran abundance and size in August coupled with large percentages of Daphnia in juvenile American shad stomachs indicated heavy planktivory. Smaller juvenile American shad primarily fed on Daphnia in August, but switched to more evasive copepods as the mean size of fish increased and Daphnia abundance declined. Because Daphnia are particularly important prey items for subyearling Chinook salmon in mainstem reservoirs in mid to late summer, alterations in the cladoceran food base is of concern for the management of outmigrating salmonids and other Columbia River fishes. ?? 2006 by the Northwest Scientific Association. All rights reserved.

Haskell, C. A.; Tiffan, K. F.; Rondorf, D. W.



Modeling selenium bioaccumulation through arthropod food webs in San Francisco Bay, California, USA  

USGS Publications Warehouse

Trophic transfer is the main process by which upper trophic level wildlife are exposed to selenium. Transfers through lower levels of a predator's food web thus can be instrumental in determining the threat of selenium in an ecosystem. Little is known about Se transfer through pelagic, zooplankton-based food webs in San Francisco Bay ([SFB], CA, USA), which serve as an energy source for important predators such as striped bass. A dynamic multipathway bioaccumulation model was used to model Se transfer from phytoplankton to pelagic copepods to carnivorous mysids (Neomysis mercedis). Uptake rates of dissolved Se, depuration rates, and assimilation efficiencies (AE) for the model were determined for copepods and mysids in the laboratory. Small (73-250 ??m) and large (250-500 ??m) herbivorous zooplankton collected from SFB (Oithona/Limnoithona and Acartia sp.) assimilated Se with similar efficiencies (41-52%) from phytoplankton. Mysids assimilated 73% of Se from small herbivorous zooplankton; Se AE was significantly lower (61%) than larger herbivorous zooplankton. Selenium depuration rates were high for both zooplankton and mysids (12-25% d-1), especially compared to bivalves (2-3% d-1). The model predicted steady state Se concentrations in mysids similar to those observed in the field. The predicted concentration range (1.5-5.4 ??g g -1) was lower than concentrations of 4.5 to 24 ??g g-1 observed in bivalves from the bay. Differences in efflux between mysids and bivalves were the best explanation for the differences in uptake. The results suggest that the risk of selenium toxicity to predators feeding on N. mercedis would be less than the risk to predators feeding on bivalves. Management of selenium contamination should include food webs analyses to focus on the most important exposure pathways identified for a given watershed.

Schlekat, C. E.; Purkerson, D. G.; Luoma, S. N.



Mesozooplankton community development at elevated CO2 concentrations: results from a mesocosm experiment in an Arctic fjord  

NASA Astrophysics Data System (ADS)

The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world oceans. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated pCO2 are yet lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 ?atm to 1420 ?atm. Samples were taken weekly over a six-week period with an Apstein net (55 ?m mesh size) in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analyzed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (cirripeds, polychaetes, bivalves, gastropod, and decapods) dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica) were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms; the pCO2 had no significant effect on the overall community structure. However, single taxa responded to elevated CO2 concentrations. The ratio of cirripedia nauplii to cypris larvae, the next developmental stage, in the sediment traps averaged over the entire experiment increased with pCO2 and this suggests that increased pCO2 may have delayed their development. Also, the number of bivalves, averaged over the experimental period, decreased significantly with increasing pCO2. The nature of the CO2 effect, either direct or indirect, remains open and needs to be addressed in future.

Niehoff, B.; Knüppel, N.; Daase, M.; Czerny, J.; Boxhammer, T.



Mesozooplankton community development at elevated CO2 concentrations: results from a mesocosm experiment in an Arctic fjord  

NASA Astrophysics Data System (ADS)

The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world ocean. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated CO2 are still lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 ?atm to 1420 ?atm. Vertical net hauls were taken weekly over about one month with an Apstein net (55 ?m mesh size) in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analysed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (Cirripedia, Polychaeta, Bivalvia, Gastropoda, and Decapoda) dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica) were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms and the pCO2 had no significant effect on the overall community structure. Also, we did not find significant relationships between the pCO2 level and the abundance of single taxa. Changes in heterogeneous communities are, however, difficult to detect, and the exposure to elevated pCO2 was relatively short. We therefore suggest that future mesocosm experiments should be run for longer periods.

Niehoff, B.; Schmithüsen, T.; Knüppel, N.; Daase, M.; Czerny, J.; Boxhammer, T.



Mesozooplankton community seasonal succession and its drivers: Insights from a British Columbia, Canada, fjord  

NASA Astrophysics Data System (ADS)

The mesozooplankton dynamics in Rivers Inlet, a fjord in Central British Columbia, Canada, were studied from March to June of 2008, 2009 and 2010 to assess the interannual, seasonal, and spatial variability in zooplankton abundance and community structure under different physical environments and spring bloom scenarios. Samples were collected fortnightly during 2008-2009 and monthly in 2010 and provide one of the few multi-year zooplankton time series in the region. Two distinct zooplankton communities characterized the observed succession pattern. The winter-spring group was described by the presence of small, year-round omnivorous zooplankton: bryozoan cyphonautes, Microcalanus spp., Microsetella spp., Oithona spp., and Oncaea spp., as well as by large, diapausing copepods such as Eucalanus bungii, Neocalanus plumchrus, and Calanus marshallae and the euphausiids Thysanoessa spinifera. By contrast, the spring-summer community showed an increased abundance of Acartia longiremis, cladocerans, Limacina helicina, Metridia pacifica, Euphausia pacifica, appendicularians, Clione limacina, chaetognaths, polychaetes, Pseudocalanus spp., ostracods, and amphipods. The timing of zooplankton succession was consistently associated with the timing of the spring bloom, and was delayed in 2009 when the spring bloom occurred in May rather than April. The zooplankton succession dynamics are discussed in terms of dominant feeding guild structure to highlight the potential mechanisms of succession. Spatial variability in zooplankton distribution was mainly influenced by river flow and exchanges with adjacent coastal waters.

Tommasi, Désirée; Hunt, Brian P. V.; Pakhomov, Evgeny A.; Mackas, Dave L.



Responses of seabirds, in particular prions ( Pachyptila sp.), to small-scale processes in the Antarctic Polar Front  

NASA Astrophysics Data System (ADS)

Small-scale distribution patterns of seabirds in the Antarctic Polar Front (APF) were investigated in relation to other biological, physical, and chemical features during the ANT-XIII/2 research cruise of R.V. Polarstern from December 1995 to January 1996. The APF is characterized by steep gradients in sea-surface temperature and salinity. Within the APF, gradient zones were closely associated with elevated levels of primary production, chlorophyll- a (chl- a) concentrations, and zooplankton densities. Even broad-billed prions (' Pachyptila vittata-group'), which dominated the seabird community by 83% in carbon requirements, showed small-scale distributional patterns that were positively related to primary production, chl- a, and total zooplankton densities. The findings demonstrate a close, direct link between fine-scale physical processes in the APF and biological activity through several food web levels up to that of zooplankton-eating seabirds. Broad-billed prions appeared to forage on very small copepods ( Oithona spp.) in close association with the front. Fish- and squid-eating predators showed poor correlations with small-scale spatial structures of the APF. However, in a wider band around the APF, most top predators did occur in elevated densities, showing gradual spatio-temporal diffusion of the impact of the APF on higher trophic levels.

van Franeker, Jan A.; van den Brink, Nico W.; Bathmann, Ulrich V.; Pollard, Raymond T.; de Baar, Hein J. W.; Wolff, Wim J.


Crustacea in Arctic and Antarctic sea ice: distribution, diet and life history strategies.  


This review concerns crustaceans that associate with sea ice. Particular emphasis is placed on comparing and contrasting the Arctic and Antarctic sea ice habitats, and the subsequent influence of these environments on the life history strategies of the crustacean fauna. Sea ice is the dominant feature of both polar marine ecosystems, playing a central role in physical processes and providing an essential habitat for organisms ranging in size from viruses to whales. Similarities between the Arctic and Antarctic marine ecosystems include variable cover of sea ice over an annual cycle, a light regimen that can extend from months of total darkness to months of continuous light and a pronounced seasonality in primary production. Although there are many similarities, there are also major differences between the two regions: The Antarctic experiences greater seasonal change in its sea ice extent, much of the ice is over very deep water and more than 80% breaks out each year. In contrast, Arctic sea ice often covers comparatively shallow water, doubles in its extent on an annual cycle and the ice may persist for several decades. Crustaceans, particularly copepods and amphipods, are abundant in the sea ice zone at both poles, either living within the brine channel system of the ice-crystal matrix or inhabiting the ice-water interface. Many species associate with ice for only a part of their life cycle, while others appear entirely dependent upon it for reproduction and development. Although similarities exist between the two faunas, many differences are emerging. Most notable are the much higher abundance and biomass of Antarctic copepods, the dominance of the Antarctic sea ice copepod fauna by calanoids, the high euphausiid biomass in Southern Ocean waters and the lack of any species that appear fully dependent on the ice. In the Arctic, the ice-associated fauna is dominated by amphipods. Calanoid copepods are not tightly associated with the ice, while harpacticoids and cyclopoids are abundant. Euphausiids are nearly absent from the high Arctic. Life history strategies are variable, although reproductive cycles and life spans are generally longer than those for temperate congeners. Species at both poles tend to be opportunistic feeders and periods of diapause or other reductions in metabolic expenditure are not uncommon. PMID:16905428

Arndt, Carolin E; Swadling, Kerrie M



Latitudinal distribution of mesozooplankton in the off-equatorial northeastern Pacific before and after the 1998/99 La Niña event.  


Factors affecting mesozooplankton distributions in the northeastern tropical Pacific Ocean were investigated using data obtained along a meridian line (5 degrees -12 degrees N, 131.5 degrees W) in the summers of 1998, 1999, and 2003. The survey periods corresponded to a sharp transition between the 1997-1998 El Niño and 1998-1999 La Niña events, the 1999 La Niña event, and near-normal conditions after the moderate 2002-2003 El Niño in the equatorial Pacific. A strong upwelling in the divergence zone from 10.5 degrees to 11 degrees N caused a shoaling of the thermocline depth (approximately 30 m), resulting in increases in nitrate and phytoplankton chlorophyll a (chl-a) concentrations, and, in turn, mesozooplankton abundance during the La Niña in 1999. In contrast, in 1998, remnants of El Niño characteristics, deeper thermocline depth (60-150 m) and warm surface water (>28 degrees C), led to low concentrations of nitrate, chl-a and low mesozooplankton abundance, except in the convergence zone around 7 degrees N. The thermocline depth and nitrate concentration obtained during the near-normal period in 2003 corresponded to intermediate values as compared to those obtained during El Niño and La Niña conditions. Interannual changes in the position and strength of ecotones, such as divergence and convergence zones, affected mesozooplankton community structure and cyclopoid-to-calanoid ratios along the 131.5 degrees W meridian line. The clustering pattern of the mesozooplankton community was mostly characterized by calanoid (mainly Clausocalanus sp.) and cyclopoid (mainly Oncaea sp.) copepods, accounting for most of the observed differences among groups during the study period. Cyclopoids and calanoids were more abundant in 1999 than in 1998 or 2003, with a sharp increase to the north, while they were less abundant to the north in 1998 and 2003. The cyclopoid-to-calanoid ratio peaked in the convergence zone in 1998 and the divergence zones in 1999 and 2003, apparently due to the strength and location of the ecotones. Principal component analysis (PCA) with environmental factors and dominant mesozooplankton groups showed that dominant groups were affected by nitrate and chl-a concentrations in 1998, by sigma-t (water density), nitrate and chl-a concentrations in 1999, and by sigma-t, salinity and chl-a concentration (except siphonophores) in 2003. Latitudinal distribution of thermocline depth before and after the 1998/99 La Niña event showed a distinct interannual difference. The abundance of mesozooplankton in the divergence zone in 1999 was distinctively higher than abundances found in the convergence and divergence zones in 1998 and 2003, which resulted from the shallow thermocline depth due to an intensified upwelling during the strong 1998-1999 La Niña event. PMID:18093643

Kang, Jung-Hoon; Kim, Woong-Seo; Chang, Kyung-Il



Grazing by meso- and microzooplankton on phytoplankton in the upper reaches of the Schelde estuary (Belgium/The Netherlands)  

NASA Astrophysics Data System (ADS)

In contrast with the marine reaches of estuaries, few studies have dealt with zooplankton grazing on phytoplankton in the upper estuarine reaches, where freshwater zooplankton species tend to dominate the zooplankton community. In spring and early summer 2003, grazing by micro- and mesozooplankton on phytoplankton was investigated at three sites in the upper Schelde estuary. Grazing by mesozooplankton was evaluated by monitoring growth of phytoplankton in 200 ?m filtered water in the presence or absence of mesozooplankton. In different experiments, the grazing impact was tested of the calanoïd copepod Eurytemora affinis, the cyclopoid copepods Acanthocyclops robustus and Cyclops vicinus and the cladocera Chydorus sphaericus, Moina affinis and Daphnia magna/pulex. No significant grazing impact of mesozooplankton in any experiment was found despite the fact that mesozooplankton densities used in the experiments (20 or 40 ind. l-1) were higher than densities in the field (0.1 6.9 ind. l-1). Grazing by microzooplankton was evaluated by comparing growth of phytoplankton in 30 and 200 ?m filtered water. Microzooplankton in the 30 200 ?m size range included mainly rotifers of the genera Brachionus, Trichocerca and Synchaeta, which were present from 191 to 1777 ind. l-1. Microzooplankton had a significant grazing impact in five out of six experiments. They had a community grazing rate of 0.41 1.83 day-1 and grazed up to 84% of initial phytoplankton standing stock per day. Rotifer clearance rates estimated from microzooplankton community grazing rates and rotifer abundances varied from 8.3 to 41.7 ?l ind.-1 h-1. CHEMTAX analysis of accessory pigment data revealed a similar phytoplankton community composition after incubation with and without microzooplankton, indicating non-selective feeding by rotifers on phytoplankton.

Lionard, M.; Azemar, F.; Bouletreau, S.; Muylaert, K.; Tackx, M.; Vyverman, W.



The structure of the benthic macrofaunal assemblages and sediments characteristics of the Paraguaçu estuarine system, NE, Brazil  

NASA Astrophysics Data System (ADS)

The structure of the benthic macrofaunal assemblages of the estuarine portion of Paraguaçu River, NE, Brazil, and its relationship with surface sediment characteristics (trace metals, PAHs, nutrients and grain size) and physical variables were investigated at ten stations on two contrasting occasions, summer (dry season) and winter (rainy season). A total of 1258 individuals (632 in winter and 626 in summer) and 62 taxa representing polychaetes, crustaceans, bivalves, echinoderms, bryozoans, sponges, cnidarians and cephalochordates were collected. Benthic assemblages in the upper estuary were unlike those in the lower estuary and a clear substitution of benthic taxa along the estuary was observed. Macrofaunal invertebrates in the low salinity region, composed of coarse sediments, were dominated by tellinids, venerids (bivalves), cirolanids (isopods), cyclopoids (copepods), and nereidids (polychaetes). While the high salinity region, composed of fine sediments, were dominated by nuculids (bivalves), cirratulids (polychaetes), and by amphiurids (ophiuroids). The Paraguaçu estuarine system is not severely affected by anthropogenic activities. In the great majority of the study sites, concentrations of trace metals and PAHs in the sediments were near background values. Nutrients values were also low. We formulated new models of taxon distribution and suggested detailed studies on the effects of salinity variation and studies using functional approaches to better understand the processes causing the spatial patterns in tropical estuarine benthic assemblages.

Barros, Francisco; Hatje, Vanessa; Figueiredo, Maria Betânia; Magalhães, Wagner Ferreira; Dórea, Haroldo Silveira; Emídio, Elissandro Soares



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

USGS Publications Warehouse

Diet and growth of larval lake herring (Coregonus artedi) and lake whitefish (Coregonus clupeaformis) were compared in mesocosm experiments in a small mesotrophic lake in southeastern Michigan. Fish were sampled from single-species and mixed assemblages in 2-m3 cages for 8 weeks during April and May. Both species initially ate mostly cyclopoid copepodites and small cladocerans (Bosmia spp.). Schoener's index of diet overlap showed considerable overlap (70-90%). Lake whitefish ate Daphnia spp. and adult copepods about 2 weeks earlier than did lake herring, perhaps related to their larger mean mouth gape. Lake whitefish were consistently larger than lake herring until the eighth week, especially in the sympatric treatments. Lake whitefish appeared to have a negative effect on the growth of lake herring, as lake herring in mixed-species treatments were smaller and weighed less than lake herring reared in single-species treatments. The diet similarities of lake whitefish and lake herring larvae could make them competitors for food in the Great Lakes. The greater initial size of lake whitefish could allow them to eat larger prey earlier and thereby limit availability of these prey to lake herring at a crucial period of development.

Davis, Bruce M.; Todd, Thomas N.



A new species of Metacyclops Kiefer, 1927 (Copepoda, Cyclopidae, Cyclopinae) from the Chihuahuan desert, northern Mexico  

PubMed Central

Abstract A new species of the freshwater cyclopoid copepod genus Metacyclops Kiefer, 1927 is described from a single pond in northern Mexico, within the binational area known as the Chihuahuan Desert. This species belongs to a group of Metacyclops species with a 3443 spine formula of swimming legs. It is morphologically similar to Metacyclops lusitanus Lindberg, 1961 but differs from this and other congeners by having a unique combination of characters, including a caudal rami length/width proportion of 3.5–3.8, a innermost terminal seta slightly longer than the outermost terminal seta, intercoxal sclerites of legs 1-4 naked, a strong apical spine of the second endopodal segment of leg 1 and one row of 6-8 small spinules at the insertion of this spine. The finding of this species represents also the first record of the genus in Mexico and the third in North America, where only two other species, Metacyclops gracilis (Lilljeborg, 1853)and Metacyclops cushae Reid, 1991 have been hitherto reported. This is also the first continental record of a species of Metacyclops from an arid environment in the Americas. This species appears to be endemic to the Chihuahuan Desert, thus emphasizing the high endemicity of this area.

Mercado-Salas, Nancy F.; Suarez-Morales, Eduardo; Maeda-Martinez, Alejandro M.; Silva-Briano, Marcelo



Zooplankton community resilience and aquatic environmental stability on aquaculture practices: a study using net cages.  


Fish farming in net cages causes changes in environmental conditions. We evaluated the resilience of zooplankton concerning this activity in Rosana Reservoir (Paranapanema River, PR-SP). Samples were taken near the net cages installed at distances upstream and downstream, before and after net cage installation. The resilience was estimated by the decrease in the groups' abundance after installing the net cages. The zooplankton community was represented by 106 species. The most abundant species were Synchaeta pectinata, S. oblonga, Conochilus coenobasis, Polyarthra dolichoptera and C. unicornis (Rotifera), Ceriodaphnia cornuta, Moina minuta, Bosmina hagmanni and C. silvestrii (Cladocera) and Notodiaptomus amazonicus (Copepoda). The resilience of microcrustaceans was affected in the growing points as this activity left the production environment for longer, delaying the natural ability of community responses. Microcrustaceans groups, mainly calanoid and cyclopoid copepods, had a different return rate. The net cage installation acted as a stress factor on the zooplankton community. Management strategies that cause fewer risks to the organisms and maximize energy flow may help in maintaining system stability. PMID:22437379

Dias, J D; Simões, N R; Bonecker, C C



[Spatiotemporal characteristics of zooplankton community structure and diversity in the strong temperature increment seawaters near Guohua power plant in Xiangshan Bay].  


To explore the spatiotemporal characteristics of the zooplankton community structure and diversity in the strong temperature increment seawaters near a power plant, zooplankton samples were seasonally collected in duplicate by the type II net with mesh size of 160 microm at 10 stations near Guohua power plant in Xiangshan Bay in 2011. The results showed that a total of 62 species (including larvae) were identified in the samples, and the average abundance was 9 531.1 ind x m(-3). In the seawaters, zooplankton communities were mainly composed of copepods and pelagic larvae, and pelagic larvae were the dominant with an average percentage of abundance reached up to 66.6%. Analysis of similarities demonstrated that significant differences existed in zooplankton community structures among different months (P < 0.01). In these zooplankton communities, there were 18 dominant species controlling these community structures, among which the most important discriminating species were Centropages tenuiremis, Oithona similis, Oithona fallax, Acartia clausi, Clausocalanus furcatus, Paracalanus aculeatus and Paracalanus parvwus. GLM analysis indicated that diversity indices were also significantly different among different months (P < 0.01). According to the calculation results, the inflection point, where the diversity index began to decrease with increasing water temperature, fell within 20.31-22.31 degrees C. In sections, the average water temperature in the 0.2 km section (D02), away from the outfall, was 2.16: higher than that in the 2 km section. Driven by temperature, the main dominant species such as C. tenuiremis and O. similis tended to move into the 0.2 km section, while A. clause and especially large zooplankton tended to stay away from the outfall, and then gathered in the 1.2 km section. As a result, the number of species (33 species) and abundance (5 522.8 ind x m(-3)) were minimum in the section D02, while the number of species (53 species) and abundance (16 491.0 ind x m(-3)) reached the highest in the 1.2 km section. Meanwhile, diversity indices in the 0.2 km section were also obviously lower than those in other sections. Linear regression analysis showed that the diversity indices significantly decreased with increasing water temperature (P < 0.01). The zooplankton richness decreased by 12.3% when the water temperature increased by 1 degrees C. PMID:23798135

Zhu, Yi-Feng; Huang, Jian-Yi; Lin, Xia; Yang, Ying; Xing, Chao; Yan, Xiao-Jun



Zooplankton species composition, abundance and biomass on the eastern Bering Sea shelf during summer: The potential role of water-column stability and nutrients in structuring the zooplankton community  

NASA Astrophysics Data System (ADS)

The southeastern Bering Sea sustains one of the largest fisheries in the United States, as well as wildlife resources that support valuable tourist and subsistence economies. The fish and wildlife populations in turn are sustained by a food web linking primary producers to apex predators through the zooplankton community. Recent shifts in climate toward warmer conditions may threaten these resources by altering productivity and trophic relationships in the ecosystem on the southeastern Bering Sea shelf. We examined the zooplankton community near the Pribilof Islands and on the middle shelf of the southeastern Bering Sea in summer of 1999 and 2004 to document differences and similarities in species composition, abundance and biomass by region and year. Between August 1999 and August 2004, the summer zooplankton community of the middle shelf shifted from large to small species. Significant declines were observed in the biomass of large scyphozoans ( Chrysaora melanaster), large copepods ( Calanus marshallae), arrow worms ( Sagitta elegans) and euphausiids ( Thysanoessa raschii, T. inermis) between 1999 and 2004. In contrast, significantly higher densities of the small copepods ( Pseudocalanus spp., Oithona similis) and small hydromedusae ( Euphysa flammea) were observed in 2004 relative to 1999. Stomach analyses of young-of-the-year (age 0) pollock ( Theragra chalcogramma) from the middle shelf indicated a dietary shift from large to small copepods in 2004 relative to 1999. The shift in the zooplankton community was accompanied by a 3-fold increase in water-column stability in 2004 relative to 1999, primarily due to warmer water above the thermocline, with a mean temperature of 7.3 °C in 1999 and 12.6 °C in 2004. The elevated water-column stability and warmer conditions may have influenced the zooplankton composition by lowering summer primary production and selecting for species more tolerant of a warm, oligotrophic environment. A time series of temperature from the middle shelf indicates that the warmer conditions in 2004 are part of a trend rather than an expression of interannual variability. These results suggest that if climate on the Bering Sea shelf continues to warm, the zooplankton community may shift from large to small taxa which could strongly impact apex predators and the economies they support.

Coyle, Kenneth O.; Pinchuk, Alexei I.; Eisner, Lisa B.; Napp, Jeffrey M.



Parasitic crustaceans as vectors of viruses, with an emphasis on three penaeid viruses.  


Parasitic crustaceans serve as both hosts and vectors of viruses as well as of parasites and other microbial pathogenic agents. Few of the presumably numerous associations are known, but many can be anticipated. Recently, branchiurans and gnathiid isopods have been documented to host helminths and blood parasites. Because the agents can be observed readily with a microscope, these are better recognized than are the smaller viral, bacterial, and fungal agents. Some agents are harmful to the host of the crustacean parasite and others are not. Viruses probably fit both these categories, since viruses that do not appear pathogenic are often seen in ultrastructural images from a range of invertebrate hosts, including crustaceans. Some viruses have been implicated in causing disease in the host, at least under appropriate conditions. For example, lymphocystis virus may possibly be transmitted to the dermis of its fish hosts by copepods and to the visceral organs by a cymothoid isopod. Similarly, argulid branchiurans seem to transmit the viral agent of spring viremia of carp as well as carp pox, and copepods have been implicated in transmitting infectious hematopoietic necrosis, infectious salmon anemia, and infectious pancreatic necrosis to salmon. Other viruses can be vectored to their hosts through an additional animal. We exposed three viruses, Taura syndrome virus (TSV), white spot syndrome virus (WSSV), and yellowhead virus (YHV), all of which cause mortalities in wild and cultured penaeid shrimps, to crustacean parasites on fish and crabs. Using real-time polymerase chain reaction analysis, we show that TSV in the cyclopoid copepod Ergasilus manicatus on the gill filaments of the Gulf killifish, Fundulus grandis, the acorn barnacle Chelonibia patula on the carapace of the blue crab, Callinectes sapidus, and gooseneck barnacle Octolasmis muelleri on the gills of C. sapidus, can replicate for at least 2 weeks and establish what should be an infective dose. This result was additionally supported by positive in situ hybridization reactions. All three parasites are the first known non-penaeid hosts in which replication occurs. The mean log copy number of WSSV also suggested that replication occurred in E. manicatus. The mean log copy number of YHV gradually decreased in all three parasites and both hosts over the 2-week period. The vector relationships indicate an additional potential means of transmitting and disseminating the disease-causing agents to the highly susceptible and economically valuable penaeid shrimp hosts. PMID:21669853

Overstreet, Robin M; Jovonovich, Jean; Ma, Hongwei



Endemism of subterranean Diacyclops in Korea and Japan, with descriptions of seven new species of the languidoides-group and redescriptions of D. brevifurcus Ishida, 2006 and D. suoensis Ito, 1954 (Crustacea, Copepoda, Cyclopoida).  


Copepods have been poorly studied in subterranean habitats in Korea. Previous records have indicated mostly the presence of species already described from Japan, with very few endemic elements. This commonality has usually been explained by repeated dispersal across the land bridges that connected the two countries several times during the Pleistocene glacial cycles. However, the Korean Peninsula is known for pockets of Cambrian and Ordovician carbonate rocks, with more than 1,000 caves already having been explored. The relative isolation of these carbonate pockets makes for an enormous speciation potential, and the development of a high level of short-range endemism of subterranean copepods should be expected. Representatives of the genus Diacyclops Kiefer, 1927 are here investigated from a range of subterranean habitats in South Korea, with comparative material sampled from central Honshu in Japan. Morphological analyses of microcharacters, many of which are used in cyclopoid taxonomy for the first time herein, reveal high diversity in both countries. No subterranean species is found in common, although the existence of four sibling species pairs in Korea and Japan may be indicative of relatively recent speciation. We describe seven new stygobiotic species, including three from Korea (Diacyclops hanguk sp. n., Diacyclops leeae sp. n., and Diacyclops parasuoensis sp. n.) and four from Japan (Diacyclops hisuta sp. n., Diacyclops ishidai sp. n., Diacyclops parahanguk sp. n., and Diacyclops pseudosuoensis sp. n.). Diacyclops hanguk, Diacyclops parasuoensis, Diacyclops ishidai, and Diacyclops parahanguk are described from newly collected material, while the other three new species are proposed for specimens previously identified as other, widely distributed species. Diacyclops brevifurcus Ishida, 2006 is redescribed from the holotype female, and Diacyclops suoensis Ito, 1954 is redescribed from material newly collected near the ancient Lake Biwa in Japan. This research provides evidence for the importance of subterranean habitats as reservoirs of biodiversity, and also demonstrates the inadequacy of current morphological methods of identifying closely related species of copepods. The disproportionately high diversity discovered around Lake Biwa provides further evidence in support of the hypothesis about the role of ancient lakes as biodiversity pumps for subterranean habitats. A key to the East Asian species of the languidoides-group is provided. PMID:23653520

Karanovic, Tomislav; Grygier, Mark J; Lee, Wonchoel



Plankton community structure south and west of South Georgia (Southern Ocean): Links with production and physical forcing  

NASA Astrophysics Data System (ADS)

During late December 2004 and early January 2005 the plankton community to the south and west of South Georgia was investigated. Satellite imagery had shown the surface expression of a bloom over the southern shelf 1 month prior to the cruise, although by the time of sampling a well-defined sub-surface chl- a maximum was evident at 26 of the 57 stations located mainly at the western end of the southern shelf (and the bloom was declining). Nonetheless, integrated chl- a was still greater over the shelf than elsewhere (18-362 mg m -2). Macronutrient distributions essentially mirrored the distribution of chl- a biomass, with depletion greatest in the on-shelf waters at the western end of South Georgia, where the most intense surface bloom had occurred during the preceding November. Nearest neighbour clustering of microplankton and mesozooplankton data revealed the presence of two major station groups within each analysis with broadly congruent distributions. Within the microplankton analysis a southern and western shelf grouping of 18 stations was dominated by Corethron spp., Eucampia antarctica and Thalassiothrix spp. This group corresponded spatially to a shelf zooplankton grouping (12 of the 18 stations in both groups in common) in which mesozooplankton abundance was greatest. Here small copepods such as Oithona spp. and the neritic clausocalaniid Drepanopus forcipatus dominated, along with the thecate pteropod Limacina helicina, appendicularians and calanoid copepod naupliar stages. Acoustic doppler current profiler (ADCP) measurements indicated that water flow over the shelf was low and variable (<15 cm s -1). In contrast the largest station groups in both ordinations were distributed along the southern shelf-break and further off-shelf in water flowing rapidly (up to 55 cm s -1) to the southeast. Nitzschia spp., Pseudonitzschia spp., and Fragilariopsis kerguelensis were abundant here, and the zooplankton, in addition to Oithona spp., was characterized by Metridia spp., Ctenocalanus spp., Oncaea spp., and the polychaete Pelagobia longicirrata. A third group of 13 stations disclosed by the mesoplankton ordination was confined to the north and west and generally comprised outer shelf stations in deeper waters. Here zooplankton abundance was less than in the adjacent major station groupings, although Calanus simillimus was considerably more abundant than in other groups. Relationships of both micro- and zooplankton ordinations with environmental variables were modest (Spearman rank correlation, ?w=0.49-0.59), albeit complex, with interactions likely to have occurred over different timescales. High levels of ammonium over the shelf, probably resulting from microbial breakdown and zooplankton excretion, contributed most to explaining both ordinations, along with the Si(OH) 4:NO 3 deficit ratio, a measure of past nutrient use. Model output from Ocean Circulation and Climate Advanced Modelling (OCCAM) supported ADCP-derived flow measurements. Specifically, release of particles along a transect to the southwest suggested there was an extended residence time (in excess of 3 months) over the southern shelf and a slow but significant northwards transport into the Georgia Basin. The spatial extent of the shelf and the current speed and direction implied that in situ production was locally important and had the potential to contribute significantly to downstream ecosystems.

Ward, Peter; Whitehouse, Mick; Shreeve, Rachael; Thorpe, Sally; Atkinson, Angus; Korb, Rebecca; Pond, David; Young, Emma




Microsoft Academic Search

AEKtl3ACI' Concentrations of Ca, Cd, Co, Cu, Fe, Mg, Mn, Ni, Pb, Sr, and Zn in 10 surface- zooplankton samples were compared with the values determined for 12 samples collected at 100 or more meters. Average values for Cu, Fe, Mn, Ni, Pb, Sr, and Zn were higher in the deep samples. It was postulated that more of these elements

John H. Martin



EPA Science Inventory

Abstract Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven ...


Accumulation of polycyclic aromatic hydrocarbons by Neocalanus copepods in Port Valdez, Alaska  

Microsoft Academic Search

Sampling zooplankton is a useful strategy for observing trace hydrocarbon concentrations in water because samples represent an integrated average over a considerable effective sampling volume and are more representative of the sampled environment than discretely collected water samples. We demonstrate this method in Port Valdez, Alaska, an approximately 100km2 basin that receives about 0.5–2.4kg of polynuclear aromatic hydrocarbons (PAH) per

Mark G. Carls; Jeffrey W. Short; James Payne



Respiration rates of subitaneous eggs from a marine calanoid copepod: monitored by nanorespirometry  

Microsoft Academic Search

The oxygen consumption rate during embryogenesis of Acartia tonsa subitaneous eggs were measured at different temperatures (10, 15, 17, 21, 24 and 28°C) with nanorespirometry. The oxygen\\u000a consumption was constant during the embryogenesis but increased rapidly at hatching time. The mean ± SD oxygen consumption\\u000a rate increased exponentially with temperature and ranged from 0.09 ± 0.04 (10°C) to 0.54 ± 0.09 nmol O2 egg?1 h?1 (28°C). The mean ± SD Q10-value was

Pernille Nielsen; Lars H. Larsen; Hans Ramløv; Benni W. Hansen



Effect of solar ultraviolet radiation on survival of krill larvae and copepods in Antarctic Ocean  

Microsoft Academic Search

The effect of solar ultraviolet radiation on the survival rate of Antarctic zooplankton was examined in February–March in\\u000a 2002. We investigated survival rate of calyptopis larvae of Euphausia superba and late copepodite stages (IV and V) of large dominant calanoid species, Calanoides acutus and Calanus propinquus reared in quartz jars with three different radiation regimes (total radiation, exclusion of UVB,

Syuhei Ban; Nobuaki Ohi; Sandric Chee Yew Leong; Kunio T. Takahashi; Christian W. Riser; Satoru Taguchi



Copepod life cycle adaptations and success in response to phytoplankton spring bloom phenology  

Microsoft Academic Search

In a seasonal environment, the timing of reproduction is usually scheduled to maximize the survival of offspring. Within deep water bodies, the phytoplankton spring bloom provides a short time window of high food quantity and quality for herbivores. The onset of algal bloom development, however, varies strongly from year to year due to interannual variability in meteorological conditions. Furthermore, the




Quantification of copepod gut content by differential length amplification quantitative PCR (dla-qPCR)  

Microsoft Academic Search

Quantification of feeding rates and selectivity of zooplankton is vital for understanding the mechanisms structuring marine\\u000a ecosystems. However, methodological limitations have made many of these studies difficult. Recently, molecular based methods\\u000a have demonstrated that DNA from prey species can be used to identify zooplankton gut contents, and further, quantitative gut\\u000a content estimates by quantitative PCR (qPCR) assays targeted to the

Christofer Troedsson; Paolo Simonelli; Verena Nägele; Jens C. Nejstgaard; Marc E. Frischer



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

Microsoft Academic Search

Two different forces are thought to contribute to the rapid accumulation of hybrid male sterility that has been observed in\\u000a many inter-specific crosses, namely the faster male and the dominance theories. For male heterogametic taxa, both faster male\\u000a and dominance would work in the same direction to cause the rapid evolution of male sterility; however, for taxa lacking differentiated\\u000a sex

Christopher S. Willett; PM Punta Morro; AB Abalone Cove; SC Santa Cruz; PES Pescadero; PLA Playa Altamira



Midwater biomass profiles over the Madeira Abyssal Plain and the contribution of copepods  

Microsoft Academic Search

Biomass profiles for plankton and micronekton throughout the water column at a site on the Madeira Abyssal Plain, position 31° 17' N 25° 24' W, depth 5 440 m, are described. Biomass declined exponentially with depth, > 80% of the plankton and > 95% of micronekton occured between 0–1000 m. The total biomass was low, ca 2 g dry weight

H. S. J. Roe



Omnivory in the calanoid copepod Temora longicornis: feeding, egg production and egg hatching rates  

Microsoft Academic Search

We measured in laboratory experiments the ingestion, egg production and egg hatching rates of female Temora longicornis as a function of diet. The diets consisted of a diatom (Thalassiosira weissflogii), an autotrophic dinoflagellate (Heterocapsa triquetra), and a bacterivorous ciliate (Uronema sp.) given as sole foods, or combinations of these single-food items: diatom+dinoflagellate, diatom+ciliate, dinoflagellate+ciliate, and diatom+ciliate+dinoflagellate. For the three single-item

Hans G Dam; Rubens M Lopes



The reproductive cycle and life history of the Arctic copepod Calanus glacialis in the White Sea  

Microsoft Academic Search

Seasonal variations in the gonad development and sex ratio of copepodite stage V (CV) and adults were examined from February\\u000a to November in order to understand the reproductive cycle and the life history of Calanus glacialis in the White Sea. Gonad maturation, sexual differentiation and moulting to adults take place during the 2nd year of development.\\u000a Energy accumulation takes place

K. N. Kosobokova



Young whale sharks, Rhincodon typus, feeding on a copepod bloom near La Paz, Mexico  

Microsoft Academic Search

Seven small (3.2 to 5.2 m total length) whale sharks were observed suction feeding on patches of surface plankton in the Bay\\u000a of La Paz within 1 km of shore and 2 km N of the phosphate dock at San Juan de la Costa, on 1–2 November 1993. The sharks\\u000a were photographed and videotaped from the boat and by snorkelers

Eugenie Clark; Diane R. Nelson



Metabolic rates of epipelagic marine copepods as a function of body mass and temperature  

Microsoft Academic Search

Metabolic rates (oxygen consumption, ammonia excretion, phosphate excretion) have been calculated as a function of body mass (dry, carbon, nitrogen and phosphorus weights) and habitat temperature, using multiple regression. The metabolic data used for this analysis were species structured, collected from Arctic to Antarctic seas (temperature range: -1.7°C to 29.0°C). The data were further divided into geographical and\\/or seasonal groups

T. Ikeda; Y. Kanno; K. Ozaki; A. Shinada




EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...


Laboratory culture, growth rate, and feeding behavior of a planktonic marine copepod  

Microsoft Academic Search

ABSTRACX Rhincalnnus nasutus was cultured through scvcn consecutive generations in l%litcr carboys when provided with a mixture of diatoms and Artemia salina nauplii as food. The mean generation length was 8.7 weeks, similar to that of the local field population of this species during some seasons. Fecundity of laboratory-reared animals was lower than that of the field population. Instantaneous coefficients




Cladistics of Sunaristes , a genus of harpacticoid copepods associated with hermit crabs  

Microsoft Academic Search

Four species of Sunaristes (Canuellidae) are known to live in association with hermit crabs and exhibit a degree of host specificity. Although hermit crabs are common in many parts of the world, Sunaristes is notably absent from waters of the New World. The phylogeny of Sunaristes is here examined through a cladistic analysis. The reconstructed phologeny indicates that S. inaequalis

Ju-shey Ho



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

Microsoft Academic Search

There is now ample evidence that ocean acidification caused by the uptake of additional carbon dioxide from the atmosphere at the ocean surface will severely impact on marine ecosystem structure and function. To date, most research effort has focused on the impact of ocean acidification on calcifying marine organisms. These include the dissolution of calcifying plankton, reduced growth and shell

L. Seuront



The Copepods South of Dog Keys Pass: Their Abundance, Distribution, Seasonal Variation, Temperature and Salinity Tolerances.  

National Technical Information Service (NTIS)

Two hundred and fifty-four plankton collections made by the Gulf Coast Research Laboratory personnel were used in this study. Aliquots of the samples were taken and estimations of the numbers of each species in each sample were made. Temperature-Salinity-...

D. J. Acosta



Chromatin Diminution Process Regulates rRNA Gene Copy Number in Freshwater Copepods.  


The results of quantitative PCR (qPCR) presented in the paper clearly demonstrate that the sixteen-fold genome reduction inCyclops kolensisduring chromatin diminution (from 15.3 pg to 0.98 pg) results in a dramatic decrease in ribosomal RNA gene copy numbers in the genome of a somatic cell line by more than two orders of magnitude. The results presented allow for the consideration of the chromatin diminution as a mechanism of rDNA copy number regulation. PMID:22649664

Zagoskin, M V; Marshak, T L; Mukha, D V; Grishanin, A K



Chromatin Diminution Process Regulates rRNA Gene Copy Number in Freshwater Copepods  

PubMed Central

The results of quantitative PCR (qPCR) presented in the paper clearly demonstrate that the sixteen-fold genome reduction inCyclops kolensisduring chromatin diminution (from 15.3 pg to 0.98 pg) results in a dramatic decrease in ribosomal RNA gene copy numbers in the genome of a somatic cell line by more than two orders of magnitude. The results presented allow for the consideration of the chromatin diminution as a mechanism of rDNA copy number regulation.

Zagoskin, M. V.; Marshak, T. L.; Mukha, D. V.; Grishanin, A. K.



Mesozooplankton community structure and variability in the Scotia Sea: A seasonal comparison  

NASA Astrophysics Data System (ADS)

Mesozooplankton distribution and community structure was investigated during 3 cruises to the Scotia Sea in austral spring, summer and autumn. Three mesh sizes of Bongo nets were used during each cruise with a 53 ?m mesh net yielding on average 1.76 times higher densities (median 923,000 ind. m -2, 0-400 m) than a 100 ?m net and 7.42 times more than a 200 ?m net across all cruises. Small copepods dominated numerically across all nets with Oithona spp., Oncaea spp., Ctenocalanus citer and Microcalanus pygmaeus being particularly abundant, with sample densities of up to 3.5×10 6 ind. m -2 recorded within the top 400 m. A more even distribution of biomass among net sizes was apparent, with median net ratios (1.15-1.25) smaller and more even than for abundance. To the south of the Scotia Sea plankton maxima occurred in autumn, consistent with a later spawning in many species, whereas further north, abundance in 53 and 100 ?m nets varied little across seasons, although in the 200 ?m net there was a clear summer maximum. Median biomass increased through summer and by autumn was twice than found during spring in all parts of the Scotia Sea. Cluster analysis indicated two main station groups in all 3 seasons. To the south of the Southern boundary of the ACC (SB-ACC), Group 1 contained stations, that lay within the seasonal sea-ice zone and where zooplankton abundance and biomass was persistently low. In contrast at Group 2 stations, north of the Southern Antarctic Circumpolar Current Front (SACCF) abundance and biomass was consistently higher. Differences between the two groups were largely apparent at the population rather than at the taxonomic level. LHPR hauls to 1000 m indicated that the large seasonal migrant copepods Calanoides acutus and Rhincalanus gigas were at a more advanced stage of development in the north in spring and summer where they were generally present in the upper water column. In autumn, at all stations, C. acutus was dominated by later stages and was dispersed throughout the water column. Calanus simillimus was only abundant at Group 2 stations with older stages dominant in spring and autumn and younger stages in summer. The influence of environmental factors such as sea-ice, temperature and chlorophyll a biomass (Chl a) which may have influenced the development and seasonal succession of zooplankton populations, is briefly discussed.

Ward, Peter; Atkinson, Angus; Tarling, Geraint



Impact of zooplankton grazing on Alexandrium blooms in the offshore Gulf of Maine  

NASA Astrophysics Data System (ADS)

Zooplankton grazing was investigated by shipboard experiments during natural blooms of Alexandrium spp. in the offshore Gulf of Maine in spring and/or summer of 1998, 2000, and 2001. Grazing studies were done in conjunction with studies of accumulation of Alexandrium toxins in the zooplankton, as part of the ECOHAB-Gulf of Maine regional program. Several species of copepods, marine cladocerans, and appendicularians were allowed to graze upon natural phytoplankton assemblages, at ambient temperatures (14-17 °C). Grazing was measured by quantitative microscopic analyses of disappearance of phytoplankton cells in initial, control, and experimental food suspensions. Thus, we were able to examine grazing upon Alexandrium in comparison to grazing on other co-occurring phytoplankton taxa. Even during Alexandrium "blooms," this dinoflagellate was a minor component of the overall phytoplankton assemblage. It was present at stations where grazing experiments were conducted at levels of 0.12-7.57×10 3 cells l -1, or 0.03-3.93% of total phytoplankton cells. Maximum ingestion of Alexandrium accounted for only up to 3.2% of total cells ingested. Phytoplankton assemblages were dominated by athecate microflagellates, and to a lesser extent by diatoms and non-toxic dinoflagellates. Microflagellates were present at abundances of 159.62-793.93 cells ml -1, or 60.6-95.56% of total cells. Grazing on microflagellates accounted for 35.59-98.21% of total grazing. Grazing on Alexandrium spp. and microflagellates was generally non-selective, with these taxa being ingested in similar proportions to their availability in food assemblages. Grazing on diatoms was selective, with diatoms being disproportionately ingested, compared to their proportions in food assemblages. There were no apparent adverse effects of Alexandrium on grazers during incubations of 18-24 h, and grazer survival was 100%. Estimated daily zooplankton grazing impact on Alexandrium spp. field populations by field populations of experimental grazers averaged 5.79% (range=0-117%). Extrapolating experimentally determined grazing rates to total zooplankton assemblages increased potential grazing impact to 0-667.77% (mean=114.7%). However, these potential impacts are likely overestimations, because toxin accumulation data indicated that many of the most-abundant zooplankters ( Oithona similis copepodites and copepod nauplii) likely graze only minimally upon Alexandrium spp. Thus, antipredation effects of high concentrations of Alexandrium on some grazers reported from some laboratory studies may only occur rarely in nature, because of low individual zooplankter grazing rates on Alexandrium, and dilution of grazing upon it by grazing on other food sources such as abundant microflagellates and diatoms.

Turner, Jefferson T.; Borkman, David G.




Microsoft Academic Search

Vitellogenin (VTG) has been widely used as a biomarker of estrogenic exposure in fish, leading to the development of standardized assays for VTG quantification. However, standardized quantitative assays for invertebrate, particularly crustacean, lipovitellin (also known as vitellin (VTN)) are lacking. In this study, a fluorescence-based VTN enzyme-linked immunosorbent assay (ELISA) was developed to quantify microquantities of VTN in the estuarine,

David C. Volz; G. Thomas Chandler



Avoidance of contaminated sediments by an amphipod (Melita plumulosa), A harpacticoid copepod (Nitocra spinipes), and a snail (Phallomedusa solida).  


The distribution of contaminants is seldom homogeneous in aquatic systems. In the present study, the avoidance response of Melita plumulosa, Nitocra spinipes, and Phallomedusa solida when exposed to contaminated sediments was investigated. Test vessels were designed to allow the congruent placement of two sediments and assessment of the movement of organisms between the sediments. When exposed to reference sediment, each species dispersed evenly between test chambers regardless of differences in sediment particle size. In the presence of contaminated sediment, the magnitude and rate of avoidance varied. Avoidance assays showed that test species avoided contaminated sediment as early as 6, 6, and 24?h following exposure for N. spinipes, P. solida, and M. plumulosa, respectively. The 48-h avoidance response of M. plumulosa for nine contaminated sediments of varying toxicity showed that avoidance was generally greater for sediments which elicited greater 10-d lethality to this species. The study demonstrated that each of these species has the ability to respond to chemical cues in the environment to inhabit sediment that provides the best opportunity for survival. The avoidance response for each species indicates the potential for developing rapid screening methods to assess sediment quality. Evidence suggests that avoidance was related to sediment toxicity and that static 10-d toxicity methods are likely to overestimate toxicity for species, which would avoid contamination in heterogeneous field settings. PMID:23180416

Ward, Daniel J; Simpson, Stuart L; Jolley, Dianne F



Comparison of six sewage effluents treated with different treatment technologies—Population level responses in the harpacticoid copepod Nitocra spinipes  

Microsoft Academic Search

Since conventional treatment technologies may fail in removing many micro-pollutants, there is currently a focus on the potential of additional treatment technologies for improved sewage treatment. The aim of the present study was to evaluate six different effluents from Henriksdal Sewage Treatment Plant in Stockholm, Sweden. The effluents were; conventionally treated effluent (chemical phosphorous removal in combination with an activated

Elin Lundström; Berndt Björlenius; Markus Brinkmann; Henner Hollert; Jan-Olov Persson; Magnus Breitholtz



Limnocalanus macrurus in the Kara Sea (Arctic Ocean): an opportunistic copepod as evident from distribution and lipid patterns  

Microsoft Academic Search

Limnocalanus macrurus is an important member of the zooplankton communities of the Siberian shelf seas. During the cruise, Boris Petrov 1999, in August\\/September to the southern Kara Sea and the Ob and Yenisej estuaries, its abundance and vertical distribution were investigated. In adults, salinity tolerance, egg production, feeding and lipid composition were studied. L. macrurus occurred in water with salinities

Hans-Jürgen Hirche; Ingo Fetzer; Martin Graeve; Gerhard Kattner




EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...


In situ metabolic budget for the calanoid copepod Acartia clausi in a tropical brackish water lagoon (Ebrié Lagoon, Ivory Coast)  

Microsoft Academic Search

Simultaneous measurements of respiration, excretion and production rates were carried out several times over a year period at five representative stations of the Ebrié Lagoon. Assuming a constant assimilation efficiency rate of 69.4%, we derived metabolic budgets for carbon, nitrogen and phosphorus. Daily specific ingestion rates calculated were rather generally high, and ranged between 54 and 159% of body carbon,

M. Pagano; L. Saint-Jean



Molecular Evolution at the Cytochrome Oxidase Subunit 2 Gene Among Divergent Populations of the Intertidal Copepod, Tigriopus californicus  

Microsoft Academic Search

The cytochrome c oxidase subunit 2 gene (COII) encodes a highly conserved protein that is directly responsible for the initial transfer of\\u000a electrons from cytochrome c to cytochrome c oxidase (COX) crucial to the production of ATP during cellular respiration. Despite its integral role in electron transport,\\u000a we have observed extensive intraspecific nucleotide and amino acid variation among 26 full-length

Paul D. Rawson; Ronald S. Burton



The intertidal copepod Tigriopus japonicus small heat shock protein 20 gene ( Hsp20) enhances thermotolerance of transformed Escherichia coli  

Microsoft Academic Search

To understand the role of the Tigriopus japonicus Hsp20 gene, we isolated this gene from a whole body cDNA library and found two heat shock factor elements at the 5?-UTR. The transformed bacteria containing Tigriopus Hsp20 showed thermotolerance against heat shock (54°C) with different ranges of time. The Tigriopus Hsp20 gene is comprised of 174 amino acid residues and shows

Jung Soo Seo; Young-Mi Lee; Heum Gi Park; Jae-Seong Lee



Effects of pressure, temperature and oxygen on the oxygen consumption rate of the Midwater copepod Gaussia princeps  

Microsoft Academic Search

Gaussia princeps is shown to be a diurnal vertical migrator which spends its days below 400 m in the oxygen minimum layer and migrates to shallower depths (200 to 300 m) at night. This species consumption was measured at 3.5°, 7° and 10°C and 1, 14, 28, 61, 121 and 181 atm of hydrostatic pressure (1 atm corresponds to approximately

J. J. Childress



Feeding and respiration rates of a planktonic copepod ( Calanus sinicus ) oversummering in Yellow Sea Cold Bottom Waters  

Microsoft Academic Search

The distribution, feeding and oxygen consumption of Calanus sinicus were studied in August 2001 on a transect across Yellow Sea Cold Bottom Waters (YSCBW) and two additional transects nearby. The distribution of C. sinicus adults and copepodites stage CV appeared to be well correlated with water temperature. They tended to concentrate in the YSCBW (>10,000 ind. m -2) to avoid high surface

C. Li; S. Sun; R. Wang; X. Wang



Toxicity of the organophosphate insecticide fenthion, alone and with thermal fog carriers, to an estuarine copepod and young fish  

Microsoft Academic Search

Fenthion (O,O-dimethyl O-[3-methyl-4-methylthio-phenyl] thiophosphate; Mobay Chemical Corp., Kansas City) is an organophosphate insecticide registered as Baytex | that is used in the hygiene sector for control of flies, mosquitoes, ticks, and lice. Fenthion is also widely used in the control of agricultural pests and is recommended for control of parasites of economically important pond-cultured fish. Fenthion often is applied aerially

Catherine Q. Thompson; John W. Tucker




Microsoft Academic Search

In many terrestrial artliropods, the ability to detect polarized light is used to find geographical directions by means of sky polarization patterns which change with the sun's position in the sky (von Frisch, 1948 ; Pardi and Papi, 1953a, 1953b; Birukow, 1954 ; Vowles, 1955 ; Wellington, 1955 ; Papi, 1955 ) . Such direction finding is actually a special



Five new species of lichomolgid copepods associated with ascidians from Korea, with proposal of two new genera (Crustacea, Copepoda, Lichomolgidae)  

NASA Astrophysics Data System (ADS)

Five new species of the family Lichomolgidae associated with solitary ascidians are described from the east coast of Korea. Two new genera are proposed: Protomolgus n. gen. to incorpotate Protomolgus duplex n. sp. and P. singularis n. sp., and Dontimolgus n. gen. to incorporate Dontimolgus brevicaudatus n. sp. Protomolgus n. gen. characteristically has a four-segmented female maxilliped and a bipartite mandible. Dontimolgus n. gen. possesses a large, tooth-like process on the first maxillary segment and three spines on the third exopodal segment of leg 3. Other two new species described are Lichomolgus infirmus n. sp. and L. pectinatus n. sp.

Moon, Seong Yong; Kim, Il-Hoi



Effect of total organic content of eggs on hatching success and naupliar survival in the copepod Calanus helgolandicus  

Microsoft Academic Search

We collected female Calanus helgolandicus weekly from 12 July to 16 August 1993 at a station southwest of Plymouth, England. We estimated the amount of food available by analyzing surface-water samples for total particulate protein, carbohydrate, and lipid in three size fractions: 0.6-100, 5-100, and 10-100 pm. Size and the protein, carbohydrate, and lipid content of the eggs laid by





EPA Science Inventory

Continuous flow toxicity tests were conducted on field populations of adult Acartia tonsa collected from Narragansett Bay. Potential algal food at the collection site was estimated from ATP and chlorophyll analysis. There was positive correlation (P < 0.01) between chlorophyll a ...


Evaluation of trace metal toxicokinetics in Greenland Sea copepod and amphipod collectives from semi-static experiments on board ship  

SciTech Connect

Semi-state toxicokinetic experiments were performed during a cruise of RV {open_quotes}Polarstern{close_quotes} to the Greenland Sea for Cd, Pb, Cu and Zn in mesozooplankton collectives of Calanus hyperboreus, C. finmarchicus, Metridia longa and Themisto abyssorum, to provide first tentative information on accumulation strategies and the experimental basis for estimation of kinetic parameters of two-compartment models. This is an inevitable precondition for using these organisms as biomonitors. Our results indicate a net accumulation strategy for Cu and Pb (within the given experimental constraints), but a tendency for regulation of Zn and especially for Cd. Two-compartment models were successfully fitted to the data, leading to rate constants statistically different from zero, which were validated by independent experiments. An extrapolation to field conditions is not possible without further evaluation. The collectives investigated may be regarded as potentially suitable biomonitors of Cu and Pb, but probably not of Zn and Cd. More information is required for a wider range of external metal exposures and the potential influences of life-history status on metal toxicokinetics must be clarified, before this approach can be fully adopted in the assessment of environmental quality. 42 refs., 5 figs., 4 tabs.

Ritterhoff, J.; Zauke, G.P. [Carl von Ossietzky Universitaet Oldenburg (Germany)