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Environmental Sciences

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Theses/Dissertations

2009

Freshwater

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The Responses Of Blue Crabs (Callinectes Sapidus) To Hypoxia/Hypercapnia In Freshwater, James Martin Apr 2009

The Responses Of Blue Crabs (Callinectes Sapidus) To Hypoxia/Hypercapnia In Freshwater, James Martin

Theses and Dissertations

The present research examined respiratory responses of blue crabs to long term (4, 13, and 21 days) hypercapnic hypoxia in freshwater at 23 C. Hypoxic conditions (50-60 & 75-85 mmHg O2) were induced by allowing the crabs to consume their oxygen supply, resulting in a hypercapnic induced decrease in pH that remained through the exposure. Postbranchial hemolymph responses to hypoxia/hypercapnia in freshwater demonstrate decreases in PO2, increases in PCO2, and decreases in pH. Lactate levels decreased over time, but hemocyanin concentration was highly variable with no trends. PH, lactate, and hemocyanin observations also demonstrated high variability and a variety of …


Conservation Genetics Of A Near Threatened Freshwater Mussel Species (Lampsilis Cardium) And Improved Prospects For Recovery: How Nuclear And Mitochondrial Dna Analyses Inform Natural History And Conservation, Chad D. Ferguson Jan 2009

Conservation Genetics Of A Near Threatened Freshwater Mussel Species (Lampsilis Cardium) And Improved Prospects For Recovery: How Nuclear And Mitochondrial Dna Analyses Inform Natural History And Conservation, Chad D. Ferguson

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Freshwater mussels (Bivalvia: Unionidae) are among the most imperiled organisms in North America. While there is an urgent need for effective conservation planning and management of these organisms, important basic biological information is lacking. This research characterizes levels of genetic diversity and population structure in the Near Threatened (IUCN) freshwater mussel Lampsilis cardium in populations from Twin Creek (southwest Ohio), Little Darby and Big Darby Creeks (central Ohio), and Little Muskingum River (eastern Ohio) and assesses the extent to which regional geological events explain population structuring. Data from the congener Lampsilis ovata from Clinch River (Tennessee) are included for comparison. …