In the shallow, bar-built estuary Apalachicola Bay, the discharge of the Apalachicola River, the largest river in Florida by discharge volume, produces short residence times of water in the Bay and pronounced gradients in salinity and nutrients. This, in combination with wind- and tidal-driven circulation, generates an environment for plankton that is complex and highly dynamic. Understanding these dynamics and the factors controlling them is prerequisite for estimating phytoplankton biomass and productivity in such ecosystems. This research assessed the variability of estuarine phytoplankton in Apalachicola Bay at multiple temporal and spatial scales, utilizing high resolution spatial sampling, dye release experiments monitored with a drone, and a long-term record of water quality. Small-scale chlorophyll a (Chl a) peaks (1.3 ± 0.7 km wide) had steep gradients (3.0 ± 6.0 µg Chl a L-1 km-1) and accounted for 7.7 ± 2.7 % of the biomass observed with a flow-through water quality instrument. Winds, tides, and temperature affected Chl a peak characteristics, while the river plume front was a dynamic location of elevated Chl a. Horizontal dispersion of small-scale inert tracer patches (10-100 m) were faster than phytoplankton reproduction cycles, suggesting that small-scale phytoplankton patches may not be able to outpace physical dispersion in estuaries through growth. The evaluation of a 14-year time series of bay water quality data revealed that extreme river discharge events influenced intra- and interannual variability of Chl a. The nutrient buffering capacity of Apalachicola Bay, in conjunction with longer residence time, increased light penetration, and reduced grazing pressure, may mitigate the reduction of riverine nutrient input during drought. In contrast, tropical storms and high river discharge events may lead to periods of reduced phytoplankton biomass by increasing flushing rates of the estuary and reducing light availability. These new insights into the spatial and temporal variability of phytoplankton distribution and what’s controlling it helps coastal managers to understand how river discharge, winds, and tides affect biomass in bar-built estuaries. / A Dissertation submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the Doctor of Philosophy. / Spring Semester 2017. / April 13, 2017. / Drought, Estuaries, Phytoplankton, Rhodamine WT, River, Spatial variability / Includes bibliographical references. / Markus Huettel, Professor Directing Dissertation; Thomas Miller, University Representative; Michael Wetz, Committee Member; Kevin Speer, Committee Member; William Landing, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_552311 |
| Contributors | Geyer, Natalie L. (Natalie Louise) (authoraut), Huettel, Markus (professor directing dissertation), Miller, Thomas E. (Professor of Biological Science) (university representative), Wetz, Michael S. (committee member), Speer, Kevin G. (Kevin George) (committee member), Landing, William M. (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean, and Atmospheric Science (degree granting departmentdgg) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text, doctoral thesis |
| Format | 1 online resource (123 pages), computer, application/pdf |
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