Graduation Year

2021

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

Kimberly K. Yates, Ph.D.

Committee Member

Mark E. Luther , Ph.D.

Keywords

Carbonate, Dissolved inorganic carbon, pH, Saturation state, Tampa Bay, Total alkalinity

Abstract

Coastal and estuarine acidification impacts ecosystem health and economic resources and has both natural and anthropogenic components (Cai et al., 2021). Riverine input is one of several important factors that can influence acidification in coastal ecosystems. Rivers disgorging into coastal environments can create strong gradients, both spatial and temporal, that make accurate CO2-system characterization challenging. The work described in this thesis provides a baseline CO2-system study of four major rivers that flow into Tampa bay with an emphasis on seasonal change. As a second objective, this thesis examines the effects of HgII additions on CO2-system measurements in organic-rich estuarine waters. Recent advancements in spectrophotometric techniques using sulfonephthalein indicator dyes were implemented in my work. Measurements of surficial water samples included dissolved inorganic (CT), total alkalinity (AT), pHT (total scale), calcium (Ca2+) and major inorganic nutrients. Water samples were collected either from shore or from a U.S. Geological Survey research vessel. Each river exhibited distinct seasonal variability wherein CO2-system parameters were strongly influenced by river discharge rates. Major nutrients did not strongly correlate with river discharge, but instead correlated strongly with CO2 system parameters, CT and AT. Comparisons of seasonal riverine CO2-system and nutrient measurements with similar measurements in Tampa Bay showed that the rivers’ short-term influence on Tampa Bay’s CO2-system was modest. In contrast, the rivers were shown to be a major source of nutrients to the Bay. My examinations of HgII additions to organic rich estuarine waters showed that HgII amendments eliminated changes in CT over time, but had undesirable effects on AT and pHT. As a result, for organic rich estuarine waters, alternative sample processing methods should be considered when samples cannot be promptly analyzed. This work provides the first Bay-wide look at the riverine CO2-system of Tampa Bay, and reveals the dramatic influence of HgII on measurements of CO2-system parameters in organic rich estuarine waters.

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