Graduation Year

2014

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Marine Science

Major Professor

Robert H. Byrne, Ph.D.

Committee Member

Edward S. Van Vleet, Ph.D.

Committee Member

David W. Hastings, Ph.D

Keywords

Anayte, Chemistry, Concentration, Estuary, Ions, Mixing

Abstract

This work represents a first look at the general spatial distribution of trace metals and the inorganic carbon system in the surface waters of Tampa Bay. Tampa Bay's chemical environment bears many influences ranging from hydrological and geological to anthropogenic and meteorological. A large y-shaped estuary on the west-central side of the Florida Peninsula, Tampa Bay extends over 400 square miles and has a 2200 square mile watershed that includes extensive swamps, scrub, agricultural lands and densely urbanized areas. Reaching 37 miles from the northernmost point of Old Tampa Bay to the mouth of the estuary near the Sunshine Skyway Bridge, it is home to the largest port in Florida, and overall places 17th in the nation for tonnage. In addition to its ports, Tampa Bay supports the requirements of a broad range of industries including: ship building and repair, power generation, wastewater processing, development, and recreational and commercial fishing. The region experiences high rainfall during the summer and much reduced rainfall during the remaining portions of the year. The bay has a broad gradient of mixing intensities, with residence times ranging from 100+ days in Old Tampa Bay to less than 20 days at the mouth. Seventy-one percent of Tampa Bay's freshwater input is delivered by four primary rivers: the Hillsborough, Alafia, Manatee and Little Manatee; and the region is strongly influenced by spring outflow from the Floridan Aquifer. The largest river, the Hillsborough, spans 54 miles from the Green Swamp to its mouth in Hillsborough Bay.

Samples were collected over a two-week period in January of 2013 along 13 sites on the Hillsborough River and 26 stations in Tampa Bay. Metal concentration analyses were conducted on twelve elements using inductively coupled plasma mass spectrometry (ICP-MS). These twelve elements included sodium, lithium, magnesium, calcium, strontium, barium, vanadium, molybdenum, manganese, nickel, antimony, and uranium. Within Tampa Bay, sodium, lithium, and magnesium exhibited strongly conservative behavior (showing simple two-end-member mixing). Calcium, strontium, molybdenum, and uranium show quasi-conservative behavior, with localized deviations from simple mixing of fresh water and seawater end members. The remaining elements showed variable behavior driven by solubility, redox reactions, and/or unique localized inputs based on local geology. Comparisons of baywater calcium concentrations and the concentrations of lithium, magnesium, strontium and barium revealed simple relationships that are promising for use in interpretations of otolith chemistry of teleosts and some agnatha (Campana, 1999; Carlström, 1963).

Samples were collected from both the river and the bay for CO2 system analyses. Spectrophometric pH measurements were obtained using purified m-Cresol Purple (mCP) and the procedures of Liu et al. (2011). Dissolved inorganic carbon (DIC) was processed according to CDIAC's Guide to Best Practices, SOP:2 (Dickson, Sabine, & Christian, 2007). Total alkalinity samples were processed using the spectrophotometric procedures of Yao and Byrne (1998). Dissolved inorganic carbon in the bay ranged between 3500 µMol/L and 2250 µMol/L and, in the Hillsborough River, peaked at 3700 µMol/L just below the Green Swamp. A comparison of measured total alkalinity and calculated alkalinity (obtained using pH and DIC and CO2sys software) demonstrated the presence of substantial organic base concentrations within the bay.

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