Document Type

Report

Department/Program

Film & Media Studies

Publication Date

1997

Abstract

The changes in water quality within shallow water regions of the lower Chesapake Bay was compared seasonally from permanent stations located along transects across vegetated and unvegetated sites in shoal regions of the lower Chesapeake Bay. The effect of the seagrass bed on conditions inside compared to outside of the bed varied seasonally and could be related to bed biomass and develoment. During spring (April-June) the rapidly growing seagrass bed was a sink for nutrients, suspended inorganic particles and phytoplankton, while during the summer, as bed dieback progressed, resuspension and release of nutrients were observed. Reductions in suspended particle concentrations and light attenuation were generally not measurable until bed biomass exceeded 50-100 gdm m-2 or 25-50% vegetative cover. During April when nitrate levels in adjacent channel waters were observed to be highest (>10 μM) rapid uptake, equivalent to 48% of nitrogen requirements for seagrass growth, reduced inorganic nitrogen standing stocks 73% within the bed compared to out. An unvegetated site which previously supported seagrass demonstrated little capacity to reduce measurable levels of suspended particles or nutrients, and resuspension of bottom sediments contributed to higher levels of suspended particle concentrations and turbidity in the unvegetated shallows compared to adjacent waters. (...)

Keywords

Aquatic plants -- Chesapeake Bay (Md. and Va.), Water quality biological assessment -- Chesapeake Bay (Md. and Va.), Water quality -- Chesapeake Bay (Md. and Va.)

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