DISTRIBUTION AND FLUXES OF ORGANIC CARBON (DOC, POC) IN SMALL SUB-TROPICAL RIVERS, ESTUARIES, AND COASTAL WATERS OF TAMPA BAY, FLORIDA (USA)

Small tropical and sub-tropical rivers deliver a significant amount of dissolved material, including carbon (C), to the coastal ocean. However, the fluxes and fate of these materials are poorly quantified, and historical records of land-ocean C delivery are relatively rare. Additionally, tropical and sub-tropical estuaries are sites of intense biogeochemical processing and can significantly alter the quantity and character of materials being exported to the coastal ocean. Tampa Bay is a large estuary immediately adjacent to the Gulf of Mexico, and previous work indicates it is a site of intense biogeochemical processing and carbon storage. However, fluxes of carbon to the open ocean from large estuaries such as Tampa Bay are under-represented in our understanding of Gulf of Mexico carbon budgets. In this study, the abundance of dissolved and particulate forms of organic carbon (DOC and POC, respectively) were measured in riverine, estuarine, and coastal waters along four transects around Tampa Bay. Preliminary data indicate the delivery or large amounts of carbon via small rivers and tidal creeks to the bay, and intense biogeochmical transformations within the Bay prior to mixing with Gulf waters. DOC concentrations ranged from 1.83 – 16.30 μmol L^-1 and indicated that estuarine waters of Tampa Bay represent a large sink of organic carbon. Further study, including isotopic analysis, is necessary to understand the biogeochemical processes that are responsible for the patterns evident in DOC and POC abundance within this complex sub-tropical estuarine system.