The acute toxicity to the marine copepod Acartia tonsa Dana of four technical grade insecticides was determined by bioassay using standardized procedures, homogeneous populations and constant laboratory conditions. At a water temperature of 17 plus or min...

The estuarine copepod Acartia tonsa naturally carried diverse strains of bacteria on its body. The bacterial community composition (BCC) remained very conservative even when the copepod was fed different axenic algal species, indicating that the food per se did not much affect BCC associated with the copepod. In xenic algal treatments, however, ...

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

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

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

Cultured Acartia tonsa manifested a reproducible toxicological response through six generations. There were no statistically significant differences in the responses of F1 and F6 generations to cadmium, copper, and mercury. Cultured and field populations (parental) exposed to cad...

Little is known about the nature of bacteria associated with the surface and gut of marine copepods, either in laboratory-reared animals or in the natural environment. Nor is it known whether such animals possess a gut flora. The present report deals with studies of microorganisms isolated from healthy, laboratory-reared copepods of the species Acartia ...

Toxicity of Silver, Zinc, Copper, and Nickel to the Copepod Acartia tonsa Exposed via. Analytical Chemistry. Silver, Zn, and Ni concentrations were measured by 110mAg, 65Zn, or 63Ni radioisotopic findings (6, 26, 27). The dry mass of T. pseudonana was 2.89 � 10-11 g/cell. Ag and A. tonsa. Silver

The marine copepod Acartia tonsa and the food organism Rhodomonas salina were cultured in fully defined medium for 8 months without problems. Both organisms were also cultured in natural seawater and in a commercial salt mixture for at least two generations before the sensitivities of A. tonsa to bisphenol A, potassium dichromate, and ...

The effects of predation and spatial patchiness in food distribution on egg production of the marine calanoid copepod Acartia tonsa were investigated in the laboratory. A postexperiment egg production method was developed to override the decline in number of copepods due to predation. The copepods were able to remain in food patches about 41-47% of the ...

The grazing of subadult stages of Acartia tonsa and A. clausi and Eurytemora affinis on natural particle distributions was investigated using animals from wild populations sorted into stages. Filtering rates and particle selection are compared for various stages from late nauplius through adult, using copepods and particles from the middle of Chesapeake ...

Acartia tonsa 38 9.5 Calanus finmarchicus I-IV + + C. finmarchTCUsv:vT 2 1 .5 .25 C. minor 1 .25 .25 ~. lripos-- Ox toxum scolopax Silicoflagellatae 17 6 289 96 289 48 96 289 144 96 48 817 144 96 48 96 6 35 6 Calanoida Acartia spp. 36 36 108 CiiTimus finmarchicus I-IV 216 36 ~illrnarchicus V-VI 6 C. minor 2 Candacia

Predators influence the phenotype of prey through both natural selection and induction. We investigated the effects of grazers and nutrients on chain formation in a dinoflagellate, Cochlodinium polykrikoides, which forms dense blooms and has deleterious effects on marine ecosystems around the world. Field populations of C. polykrikoides formed longer chains than laboratory cultures without ...

The goal of the Fall Removal Experiment 1987 was to determine the processes affecting the dependent and fate of low salinity coastal water and of biological material therein during fall when winds are mainly south-to westward. Five zooplankton taxa, Acartia tonsa, (A. tonsa) Paracalanus species (sp), Temora turbinata (T. turbinata), ...

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

Calanoid copepod abundance and distribution were measured by monthly plankton tows from May through November in 1998 and March through August in 1999 in three subestuaries of the Waquoit Bay estuarine system. There was a dramatic seasonal change in the composition of calanoids in Waquoit Bay with a spring community consisting of Acartia hudsonica, Centropages hamatus, and ...

The goals of this study were to describe the diet and estimate the trophic level and food selection of Jenyns's sprat Ramnogaster arcuata, one of the common fishes in the Bah�a Blanca estuary in Argentina. The copepods Acartia tonsa [53�7% index of relative importance (I(RI))] and Eurytemora americana (13�4% I(RI)), the mysid Arthromysis magellanica ...

The association of Vibrio cholerae with zooplankton has been suggested as an important factor in transmission of human epidemic cholera, and the ability to colonize zooplankton surfaces may play a role in the temporal variation and predominance of the two different serogroups (V. cholerae O1 El Tor and O139) in the aquatic environment. To date, interactions between specific serogroups and species ...

Temperature variation resulting from thermal discharges of two power plants affected temperature tolerances and densities of two copepod species, Eurytemora affinis and Acartia tonsa. Temperature tolerances were increased genetically (next generation) provided either ambient temperature or delta T was sufficiently high. Densities also varied with ...

Unexpectedly strong geographic structures in many cosmopolitan species of marine holoplankton challenge the traditional view of their unrestrained dispersal and presumably high gene flow. We investigated cryptic lineage diversity and comparative phylogeography of a common estuarine copepod, Acartia tonsa, on the US Atlantic coast, using mitochondrial ...

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 ...

The results from the screening toxicity tests Artemia salina, Microtox{reg_sign}, and Mitochondria RET test were compared with those obtained from OSPAR (Oslo and Paris Commissions)-authorized procedures for testing of offshore chemicals (Skeletonema costatum, Acartia tonsa, Abra alba, and Corophium volutator). In this study 82 test substances (26 ...

Aquatic organisms respond to environmental challenges such as thermal stress with the rapid induction of highly conserved polypeptides known as stress proteins or heat shock proteins (Hsps). Solar ultraviolet radiation (UVR, 280-400 nm) is an important environmental stressor in marine ecosystems. Here, we present results of experiments conducted with the marine copepod Acartia ...

Aquatic organisms respond to environmental challenges such as thermal stress with the rapid induction of highly conserved polypeptides known as stress proteins or heat shock proteins (Hsps). Solar ultraviolet radiation (UVR, 280�400 nm) is an important environmental stressor in marine ecosystems. Here, we present results of experiments conducted with the marine copepod ...

The recent discovery of cryptic species in marine holoplankton, organisms that 'drift' in oceanic currents throughout their life cycle, contrasts with their potential for long-distance passive dispersal and presumably high gene flow. These observations suggest that holoplankton species are adapting to surprisingly small-scale oceanographic features and imply either limited dispersal or strong ...

Temporal variations in the biomass and species composition of zooplankton at a single midshelf station in an upwelling area off Peru can be explained to a large extent by onshore-offshore advection in the upper 20 m of the water column. During periods of strong or sustained near-surface onshore flow, peaks in biomass of zooplankton were observed at midshelf and typically oceanic species of copepod ...

Peritrich ciliates are commonly found as epibionts, colonizing living organisms, or attached to non-living substrates in freshwater, estuarine and marine environments. Several species of peritrich epibionts are obligate, which means that they are able to only colonize other organisms, while others are facultative attaching to living or non-living substrates. The peritrich Zoothamnium intermedium ...

This paper presents information from different sampling surveys carried out along the Santa Catarina coast in order to outline the biogeographical characteristics of the zooplankton in this region and identify species or groups of species with potential use as bioindicators. Based on a checklist of species of the zooplankton community in the state, it was observed that, in the warmer months of the ...

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

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) ...

The effects of a sewage effluent with no treatment on the mesozooplankton structure and the environmental quality were evaluated in the Bah�a Blanca Estuary, during June to November 1995. The highest values of particulate organic matter, nutrients and specially phosphate, were observed in the effluent discharge zone. In addition, taxa richness, mesozooplankton abundance and Shannon diversity ...

The effectiveness of auxiliary tempering pump operation at Chalk Point Steam Electric Station (SES) at reducing plant-induced mortality of aquatic biota was evaluated. Several Representative Important Species (RIS) and dominant benthic and zooplankton species were used in the evaluation as indicators of overall system-wide responses. Expected mortality with and without auxiliary pump operation was ...

The copepod species Eurytemora affinis and Acartia tonsa showed 50 to 60% mortality in cooling water with 0.5ppm Cl2 or BrCl (applied dosage) when entrained in the cooling system. However, after 5 min contact time, the biotoxicity was reduced to insignificant levels, hence mortalities in the mixing zone, given the applied dosage, would be negligible. There ...

Over the last three decades, the abundance of the bivalve Mercenaria mercenaria, a benthic suspension feeder, has declined dramatically in the Great South Bay, Long Island, NY. This decline undoubtedly has had significant impacts on planktonic dynamics in the estuary and may be a contributing factor to the appearance of blooms of Aureococcus anophagefferens (brown tides) that began in 1985. We ...

The routine operation of offshore oil production platforms results in the discharge to the sea of produced water after it has been separated from oil drawn from the reservoir. Discharge of produced water in the UK sector of the North Sea is given an exemption from the provisions of the 1971 Prevention of Oil Pollution Act providing the monthly average oil-in-water content measured twice per day ...

The mass occurrence of toxic cyanobacteria is a recurrent phenomenon in the Baltic Sea. Grazers may obtain toxins either through ingestion or by direct exposure to dissolved toxins. Despite this, there is little knowledge about the accumulation of cyanobacterial toxins in planktonic organisms present during these blooms. Toxin analyses of tissue samples are complicated to carry out and, because of ...

SummaryEffects 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 ...

In Argentina, as in other countries of Latin America, cholera has occurred in an epidemic pattern. Vibrio cholerae O1 is native to the aquatic environment, and it occurs in both culturable and viable but nonculturable (VNC) forms, the latter during interepidemic periods. This is the first report of the presence of VNC V. cholerae O1 in the estuarine and marine waters of the R�o de la Plata and ...

Sexual selection is potentially important in marine zooplankton, presumably the most abundant metazoans on earth, but it has never been documented. We examine the conditions for sexual selection through mate choice and describe mating preferences in relation to size in a marine zooplankter, the pelagic copepod Acartia tonsa. Males produce spermatophores at ...

Copepods are an important planktonic food source for fish species. High predation has led to the development of effective escape responses with short reaction times (less than 2 ms), maximum escape velocities of over 500 body lengths per second and shear sensitivity as low as 1.5s-1. Using high speed digital holography (2 kfps), we measure 3-D distributions of velocity generated by a dwarf ...

A standard dredged material bioassay was conducted with high levels of organotins to assess the toxicity and bioavailability of organotins associated with sediment and to determine if this sediment would qualify for ocean disposal. This study concluded that high levels of organotins in sediments do not a priori indicate a significant adverse impact on the marine environment after ocean disposal. ...

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 ...

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 ...

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 ...

Research on the combined effects of chlorine, ammmonia and temperature on marine plankton have been carried out for 20 months. To date continuous-flow bioassays have been conducted on lobster larvae (Homarus americanus), oyster larvae (Crassostrea virginica), copepods (Acartia tonsa), rotifers (Brachionus plicatilis), three juvenile and larval fish, ...

Studies on the effects of chlorine, chloramines, and temperature on marine plankton have been carried out for three years. Species studied include marine phytoplankton, lobster larvae (Homarus americanus), oyster larvae (Crassostrea virginica), copepods (Acartia tonsa), rotifers (Brachionas plicatilis), grass shrimp (Palamonetes pugio) summer flounder ...

The El Ni�o event of 1997/1998 provided an opportunity to carry out a field experiment in which the relationship of sea surface temperature and the association of Vibrio cholerae with marine plankton could be assessed in Mexican coastal and estuarine areas. Plankton samples were collected from May 1997 through June 1999. Sites included the Mexican ports of Veracruz, Coatzacoalcos and Frontera in ...

Previously undescribed motile cystophorous cercariae which develop in sporocyst-like germinal sacs in the bullomorph opisthobranch Philine aperta are experimentally shown to develop into Lecithocladium excisum (Digenea, Hemiuridae), a common stomach parasite of mackerel Scomber scombrus in the north-east Atlantic and adjacent seas. Between 3 and 8% of P. aperta from the northern Oresund, Denmark, ...

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 ...

The chaenopsid blenny Acanthemblemaria spinosa occupies topographically high locations on coral reefs where flow speeds and turbulence are frequently greater than those experienced by its congener, A. aspera, which occupies locations close to the reef surface. To investigate the adaptive mechanisms resulting in this microhabitat differentiation, the foraging effort and success of these fishes were ...

The use of functional endpoints in risk assessment of pollutants for marine pelagic communities is scarce, especially for the function of zooplankton communities. This work presents a rapid, inexpensive and ecologically relevant technique to assess the effect of toxic compounds on the grazing rates of zooplankton communities. The combination of a (14)C-tracer labelling technique with a fast (< ...

This study was jointly funded by EPRI and five electric utility companies in New England (New England Power, Northeast Utilities, United Illuminating, Vermont Yankee Nuclear, and Public Service of New Hampshire). Previous investigations had identified three major areas for further study: continuous low-level chlorination, dechlorination, and condenser biofouling control. Continuous low-level ...

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 ...

Industrial and municipal effluents are important sources of endocrine disrupting compounds (EDCs) discharged into the aquatic environment. This study investigated the endocrine potency of wastewater and the cleaning efficiency of two typical urban Danish sewage treatment plants (STPs), using chemical analysis and a battery of bioassays. Influent samples, collected at the first STP grate, and ...

Nutritional imbalances between predator and prey are the rule rather than the exception at the lower end of food webs. We investigated the role of different grazers in the propagation of nutritionally imbalanced primary production by using the same primary producers in a three-trophic-level food chain and a four-trophic-level food chain experimental setup. The three-trophic-level food chain ...

Pursuant to a utility's intent to file for permission to build a generating station along the Nanticoke River, Maryland, a field program was conducted to update characterizations of major aquatic biota of the river in proximity to the existing power plant and a potential intake/discharge location. This characterization sampled five stations on the Nanticoke River, spanning 14 miles from ...

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, ...

The relative predation by adult, female Tortanus on their own nauplii and on developmental stages of Acartia clausii was determined by offering pairs of prey at several relative and absolute abundances. Predation was most intense on adult Acartia, less so on juvenile Acartia (nauplii and immature copepodites), and least on naupliar ...

Language: English ...