Water Quality Associated With Survival of Submersed Aquatic Vegetation Along an Estuarine Gradient

Staver, Kenneth; Staver, Lorie; Stevenson, J.

The decline of submersed aquatic vegetation (SAV) in tributaries of the Chesapeake Bay has been associated with increasing anthropogenic inputs, and restoration of the bay remains a major goal of the present multi-state "Bay Cleanup" effort. In order to determine SAV response to water quality, we quantified the water column parameters associated with success of transplants and natural regrowth over a three-year period along anestuarine gradient in the Choptank River, a major tributary on the eastern shore of Chesapeake Bay. The improvement in water quality due to low precipitation and low nonpoint source loadings during 1985-1988 provided a natural experiment in which SAV was able to persist upstream where it had not been for almost a decade. Mean water quality parameters were examined during the growing season (May-October) at 14 sites spanning the estuarinegradient and arrayed to show correspondence with the occurrence of SAY. Regrowth of SAY in the Choptank is associated with mean dissolved inorganic nitrogen < 10 I'M; mean dissolved phosphate <0.35 I'M; mean suspended sediment <20 mg 1-'; mean chlorophyll a in the water column <15 I'g 1-'; and mean light attenuation coefficient (Kd) <2 m '. These values correspond well with those derived in other parts of the Chesapeake, particularly in thelower bay, and may provide managers with values that can be used as target concentrations for nutrient reduction strategies where SAV is an issue.

Water Quality Associated With Survival of Submersed Aquatic Vegetation Along an Estuarine Gradient

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