Document Type

Statistical Report

Publication Date



Tampa Bay, Water quality, Sewage, Seagrass


Hillsborough Bay, the eastern uppermost section of the Tampa Bay system, is surrounded by a large metropolitan complex, supports extensive industrial activity, and serves as a major shipping port of fertilizer products. The Bay was determined to be highly eutrophic during the late 1960s. The City of Tampa's primary sewage treatment plant and runoff from fertilizer industry activities were considered as the major sources of excessive nutrient loading. Loadings form both these sources have been reduced during the last 10 years, which has probably been the leading cause of improved water quality parameters such as water clarity, dissolved oxygen, and chlorophyll. The improvements recorded in these parameters may, in part, be related to large biomass reductions of a planktonic blue-green alga, which used to dominate the fall and early winter phytoplankton population. Coincidental with improved water quality, seagrass and an attached macro-alga have vegetated shallow areas around the bay, which had been barren of attached vegetation for several decades.