UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

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Author: search.filters.author.Keppel, Andrew George

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    The effects of co-varying diel-cycling hypoxia and pH on disease susceptibility, growth, and feeding in Crassostrea virginica
    (2014) Keppel, Andrew George; Breitburg, Denise L; North, Elizabeth W; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Diel-cycling hypoxia and pH co-occur in shallow waters world-wide. Eutrophication tends to increase the occurrence and severity of diel cycles. We used laboratory experiments to investigate effects of diel-cycling DO and pH on acquisition and progression of infections by Perkinsus marinus, the protistan parasite which causes Dermo disease, as well as hemocyte activity, growth, and feeding in the eastern oyster, Crassostrea virginica, an important estuarine species. Diel-cycling DO increased P. marinus infection and cycling DO and pH stimulated hemocyte activity and reduced oyster growth. However, ambient environmental conditions and oyster age modulated some of these effects. Co-varying DO and pH cycles sometimes had less severe effects than either cycle independently. Oysters may acclimate to, or compensate for, effects of cycling conditions on growth. Variation in magnitude and spatial extent of cycling conditions is an important consideration when choosing restoration sites, as severe cycling conditions may hinder re-establishment of estuarine populations.