Date of Award

5-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Ocean Engineering and Marine Sciences

First Advisor

Emily Ralston

Second Advisor

Kelli Z. Hunsucker

Third Advisor

Austin L. Fox

Fourth Advisor

Robert Weaver

Abstract

This dissertation tests the hypothesis that native sponges can improve water quality and clarity in subtropical estuarine environments by examining the interaction between the marine sponge Suberites aurantiacus and fine-grained, organic-rich sediment. A husbandry review and design experiment were conducted to determine the optimal aquaculture conditions for photosynthetic marine sponges in recirculating systems. An experimental system was designed and used for a feeding trial in which sponges were fed a variety of sponge diets. No net growth was observed with any food; however, the fragments fed marine broth 2216 showed no significant decrease in growth. To examine interactions with fine-grained, organic-rich sediment, sponge fragments were dosed with sediment until the target turbidity was reached. While a progression of muck consumption and ammonia, nitrite and nitrate production was observed, issues with sponge husbandry and small sample sizes limited the results' conclusiveness. Following the laboratory experiment, mesocosms were deployed, four containing sponges and four without. Using the same procedure as in the laboratory experiment, all cubes were dosed with sediments to a target turbidity. Based on observed changes in ammonia and turbidity, the sponges appear to retain sediments at high respiration rates. However, the increases in water temperature and the algal bloom that occurred during the experimental period made it difficult to conclude the sponge’s ability to mitigate the impacts of suspended fine-grained organic-rich sediments.

Comments

5th Advisor: Dr. Kenyon Lindeman

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