The effect of the chemical and microbiological structure of biofilms on the growth of oyster spats in the Hudson River

Author

• June L. Rahman, CUNY Bernard M Baruch CollegeFollow

Date of Award

Spring 5-27-2026

Document Type

Thesis

Degree Name

B.A. with honors

Honors Designation

yes

Program of Study

Environmental Science

Language

English

First Advisor

Ana Gonzalez-Nayeck

Second Advisor

Chester Zarnoch

Third Advisor

John Stephen Gosnell

Abstract

Eastern oysters (Crassostrea virginica) are sessile suspension feeding bivalves that improve water quality through filtration and reef formation, making them crucial to the health oftheir native ecosystems. Establishing oyster habitats is a priority in Hudson River restoration efforts following significant population declines due to over harvesting, habitat loss, and pollution. Oyster spat production and attachment are influenced by biofilms; however, it is not well known how biofilm properties, such as bacterial taxonomic composition and EPS content, affect oyster larval attachment in the Hudson River. We hypothesized that intertidal surfaces,which are more exposed sunlight, would develop photosynthetic biofilms that enhance oyster spat growth via their roles in nitrogen cycling compared to subtidal surfaces, which are continuously submerged and receive less light. Here, we compared relative oyster growth, biofilm taxonomic composition, nitrogen flux dynamics, and extracellular polymeric substance (EPS) content between intertidal and subtidal reef balls. We found that intertidal reef balls support oyster growth over a greater portion of the reef ball surface than subtidal biofilms. The nitrogen flux analyses revealed that while both zones portrayed net nitrogen fixation, subtidal reef balls acted as significant ammonium sink, whereas intertidal reef balls remained nitrogen neutral, likely due to the presence of phototrophic nitrogen-fixing taxa. While biofilm EPS content was the same between subtidal and intertidal reef balls, subtidal reef ball biofilms included strict anaerobic taxa, suggesting oxygen availability might influence oyster growth. Understanding these interactions can improve restoration efforts and water quality in the Hudson River.

Recommended Citation

Rahman, June L., "The effect of the chemical and microbiological structure of biofilms on the growth of oyster spats in the Hudson River" (2026). CUNY Academic Works.
https://academicworks.cuny.edu/bb_etds/231