Date of Award

7-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Ocean Engineering and Marine Sciences

First Advisor

Dr. Kelli Hunsucker

Second Advisor

Dr. Robert Weaver

Third Advisor

Dr. Troy Nguyen

Fourth Advisor

Dr. Holly Sweat

Abstract

The Indian River Lagoon (IRL) has experienced declining water quality due to human activities involving nutrient input, leading to Harmful Algal Blooms (HABs). The Living Docks program affixes oyster mats to dock pilings to promote the settlement and recruitment of benthic filter feeders for water quality improvement. However, questions remain about filtering efficiencies of organisms that make up the mat communities, and whether organisms remove harmful species from the IRL. The pleated sea squirt, Styela plicata, is a common oyster mat resident. The goal of this thesis was to investigate what phytoplankton and bacteria S. plicata consumes, and if it retains harmful species. Gut contents and water samples underwent either genetic assessment (bacteria) or microscopy analysis (phytoplankton). Phytoplankton community composition differed between gut and water column, with gut content varying by location. A total of 115 phytoplankton species were identified, with two of the most abundant (Lingulodinium polyedrum and Amphora coffeaeformis) being potentially harmful. Bacterial community composition differed between gut and water column, and gut content varied by location. In total, 1,199 unique ESVs were identified. Bacterial orders of interest identified in the gut content included Synechococcales and Rhodobacterales. Generalist tendencies in S. plicata diet were observed due to varying availability of different prey species. This study provided insight about the filtering potential and food preference of an important Indian River Lagoon benthic filter feeder and Living Dock community member. Overall, S. plicata contributes to phytoplankton and bacteria reduction, with spatiotemporal variations in a diet that is likely selective.

Available for download on Wednesday, January 22, 2025

Included in

Oceanography Commons

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