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Full-Text Articles in Life Sciences
Seasonal Variations Of Size-Fractionated Phytoplankton Along The Salinity Gradient In The York River Estuary, Virginia (Usa), Y Sin, Rl Wetzel, I. C. Anderson
Seasonal Variations Of Size-Fractionated Phytoplankton Along The Salinity Gradient In The York River Estuary, Virginia (Usa), Y Sin, Rl Wetzel, I. C. Anderson
VIMS Articles
The dynamics of phytoplankton size structure were investigated in the freshwater, transitional and estuarine zones of the York River over an annual cycle. The contribution of large cells (microplankton, >20 mu m) to total concentrations of chlorophyll a increased downstream during winter, whereas that of small cells (nanoplankton, 3-20 mu m; picoplankton,m) increased downstream during summer. In the freshwater region, the contribution of micro phytoplankton to total concentrations of chlorophyll a was significant during warm seasons (spring and summer) but not during colder seasons (winter), whereas the contribution of small-sized cells (especially picoplankton) increased during cold seasons. Temperature, light and …
Zoosporulation Of A New Perkinsus Species Isolated From The Gills Of The Softshell Clam Mya Arenaria, Sm Mclaughlin, Bd Tall, A Shaheen, Ee Elsayed, M Faisal
Zoosporulation Of A New Perkinsus Species Isolated From The Gills Of The Softshell Clam Mya Arenaria, Sm Mclaughlin, Bd Tall, A Shaheen, Ee Elsayed, M Faisal
VIMS Articles
A gill-associated Perkinsus sp. isolated from the softshell clam (Myo arenaria) is described as a new species, P. chesapeaki sp. nov. Examination of the parasite in seawater cultures revealed life cycle stages and zoosporulation processes similar to those described for other species of the genus Perkinsus. Prezoosporangia developed thickened cell walls upon contraction of the cytoplasm and development of a distinctive clear area between the cell wall and the protoplast. Successive bipartition of the protoplast led to the formation of hundred's of zoospores within mature sporangia. Zoospores were released into seawater through one or more discharge tubes, Ultrastructural studies revealed …
Strategies For Assessing The Implications Of Malformed Frogs For Environmental Health, Jg Burkhart, Robert C. Hale
Strategies For Assessing The Implications Of Malformed Frogs For Environmental Health, Jg Burkhart, Robert C. Hale
VIMS Articles
The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state …
Progression Of Diseases Caused By The Oyster Parasites, Perkinsus Marinus And Haplosporidium Nelsoni, In Crassostrea Virginica On Constructed Intertidal Reefs, Aswani Volety, Frank O. Perkins, Roger Mann, Pr Hershberg
Progression Of Diseases Caused By The Oyster Parasites, Perkinsus Marinus And Haplosporidium Nelsoni, In Crassostrea Virginica On Constructed Intertidal Reefs, Aswani Volety, Frank O. Perkins, Roger Mann, Pr Hershberg
VIMS Articles
The progression of diseases caused by the oyster parasites Perkinsus marinus and Haplosporidium nelsoni were evaluated by periodic sampling (May 1994-December 1995) of eastern oysters Crassostrea virginica on an artificial reef located in the Piankatank River, Virginia. The infections observed were recorded as a function of: (1) prevalence and intensity; (2) oyster size and age; and (3) depth below mean low water at which the host oyster was found on the reef. Only a very small number of oysters were infected with the two species of pathogens on the oyster reef during the first 11 months of Life. In the …
Prevalence Of Perkinsus Spp. In Chesapeake Bay Soft-Shell Clams, Mya Arenaria Linnaeus, 1758 During 1990-1998, Sm Mclaughlin, M Faisal
Prevalence Of Perkinsus Spp. In Chesapeake Bay Soft-Shell Clams, Mya Arenaria Linnaeus, 1758 During 1990-1998, Sm Mclaughlin, M Faisal
VIMS Articles
Prevalence and intensity of Perkinsus spp. infections were determined in soft-shell clams Mya arenaria during 1990 to 1998 based upon incubation of rectal tissues in Ray's fluid thioglycollate medium. During the study, soft-shell clams were collected from 18 sites in the upper Chesapeake Bay in Maryland. Enlarged hypnospores were found in similar to 7% (114/1,705) of the soft-shell clams. Peak prevalences occurred in the fail of 1992 with similar to 53% (16/30) at Piney Point and 50% (15/30) at Eastern Neck, and in August 1995 with similar to 64%(18/28) and similar to 37% (11/30) at Cedar Point and Piney Point, …