Date Awarded


Document Type


Degree Name

Master of Arts (M.A.)


Virginia Institute of Marine Science


Hypoxia and anoxia have significant deleterious ecological effects on living resources throughout many estuarine and marine ecosystems worldwide. Brief periods of low oxygen facilitate transfer of benthic production to higher trophic levels as many benthic infaunal species have shallower sediment depth distributions during hypoxic events. A baited time-lapse camera equipped with a water quality datalogger was used to document in situ exploitation of oxygen-stressed benthic invertebrate prey organisms by mobile fish and crustacean predators during alternating normoxia-hypoxia cycles in the York River. Based on photographic and diver observations, this hypoxiainduced benthic-pelagic transfer of production is more likely to occur when environmental dissolved oxygen concentrations rise above an apparent threshold between 1 and 2 ml/1. When oxygen concentrations decline below 2 ml/1, the functional response of the predator to increased prey availability is interrupted. There is no energy gain by the predator until oxygen concentrations rise above this critical level when predators return to affected areas and resume feeding activity.



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