Date of Award
2023
Document Type
Dissertation
Publication Status
Version of Record
Submission Date
October 2026
Thesis/Dissertation Advisor [Chair]
Lapointe, Brian
Abstract
Eutrophication of urbanized estuaries is a global issue that continues to worsen as coastal development increases. The Indian River Lagoon (IRL) on Florida’s east-central coast is a eutrophic estuary that is experiencing harmful algal blooms of macroalgae and phytoplankton, as well as widespread seagrass losses. This is concerning as seagrasses provide many ecosystem services, including the provision of essential habitat. These alterations in benthic cover can have ecosystem level effects and require further investigation. Thus, drivers and effects of primary producer alterations in the IRL were investigated through analysis of long-term monitoring data, field surveys of faunal densities inhabiting macroalgae and bare bottom habitats, and stable nitrogen isotope (δ15N) analyses of primary producers, primary consumers, and secondary consumers. Long-term monitoring data from the northern IRL (NIRL) and Banana River Lagoon (BR) demonstrated there have been major seagrass losses coupled with increases in occurrence of the rhizophytic green macroalgae Caulerpa prolifera, which is now the dominant benthic cover in many locations. Multivariate analyses of long-term monitoring data spanning 2011-2020 suggested that the carbon to phosphorus ratio (C:P) of macroalgae is an important factor related to annual changes in benthic cover in the NIRL and BR; increased P-availability is correlated with these primary producer shifts. In situ collections of macroinvertebrates and resident fishes showed the current function and importance of macroalgae as habitat in the NIRL and BR, particularly in the relative absence of seagrass.
Extent
171 p.
Recommended Citation
Brewton, Rachel A., "NITROGEN ENRICHMENT, EUTROPHICATION, AND BOTTOM-UP TROPHIC SHIFTS IN ECOSYSTEMS OF THE INDIAN RIVER LAGOON" (2023). Electronic Theses and Dissertations 2020 - Present. 1242.
https://digitalcommons.fau.edu/etd_general/1242
Identifier
FA00014231
Comments
Includes bibliography.|Dissertation (PhD)--Florida Atlantic University, 2023.|FAU Electronic Theses and Dissertations Collection|Includes bibliography.