The annelid body, as typified by that of Nereis, consists of a presegmental prostomium, a number of segments, and a postsegmental pygidium. The larval trochosphere is unsegmented. Once proliferation of segments has started, their number increases steadily throughout most of the life of the adrenal, though the rate of proliferation declines (Clark & Clark, 1962). New segments are added posterior...

Although Beadle a9 early as 1937 suggested that the urine of Nereis diversicolor O. F. Miiller might be of lower concentration than the body fluids when this worm is hyperregulating in low salinities, there has been no direct measurement of urine concentration to support this reasonable idea. Jorgensen & Dales (1957) studied osmotic water uptake and loss in N. diversicolor and calculated that t...

An indirect fluorescent antibody test (IFAT) for detection of Toxoplasma gondii infection was validated using serum from 77 necropsied southern sea otters (Enhydra lutris nereis) whose T. gondii infection status was determined through immunohistochemistry and parasite isolation in cell culture. Twenty-eight otters (36%) were positive for T. gondii by immunohistochemistry or parasite isolation o...

The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns: the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowin...

Burrowing marine infauna are morphologically diverse and ecologically important as ecosystem engineers. The polychaetes Nereis virens and Cirriformia moorei extend their burrows by crack propagation. Nereis virens does so by everting its pharynx and C. moorei, lacking an eversible pharynx or proboscis, uses its hydrostatic skeleton to expand its anterior. Both behaviors apply stress to the burr...

There is increasing concern about the toxicities and potential risks, both still poorly understood, of silver nanoparticles for the aquatic environment after their eventual release via wastewater discharges. In this study, the toxicities of sediment associated nano (<100 nm)-, micron (2–3.5 μm)and ionic (AgNO3)-Ag on the sediment-dwelling polychaete, Nereis diversicolor, were compared after 10 ...

Eelgrass (Zostera marina) beds are known to have high ecological and economical values within coastal ecosystems of the temperate northern hemisphere although their biodiversity and functions varied greatly from sites to sites. The variation in the biomass, abundance and diversity of mobile invertebrates in eelgrass beds has been examined in relation to various abiotic and biotic factors, such ...

Acute toxicity of hexavalent chromium to 3 estuarine ammals (Corophium volutator, Macoma balthica, Nereis diversicolor) has been studied at 3 temperatures (5, 10, 15 'C) and a range of salinities (5 to 40 %o, in 5 %O increments), at time intervals of up to 384 h. Toxicity increased as temperature increased and as salinity decreased. From an analysis of variance, the significant factors and thei...