Date of Award

1-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Marine Biology and Coastal Sciences

Thesis Sponsor/Dissertation Chair/Project Chair

Matthew Schuler

Committee Member

Paul Bologna

Committee Member

Lisa Hazard

Abstract

Harmful algal blooms (HABs) threaten freshwater ecosystems by producing toxins that disrupt aquatic organism functions and pose risks to human health. This study investigated how exposure to toxin-producing cyanobacteria affects the behavior and toxin accumulation of Asian clams (Corbicula fluminea) under controlled laboratory conditions. Asian clams were collected from a freshwater site in New Jersey, maintained in greenhouse bins, and fed either Microcystis novacekii (non-toxin-forming, control N=3) or Microcystis aeruginosa (toxin-forming, experimental N=3) at 100,000 cells/mL for 28 days. Weekly behavioral assays were conducted to track shell opening, burying, clustering, valve closure, foot extension, and time to first opening. Toxin accumulation in both water and clam tissues was assessed using ELISA-based microcystin quantification. Clams exposed to toxin-forming cyanobacteria exhibited reduced activity across multiple behaviors, including burying and foot extension, suggesting stress-induced behavioral shifts. Tissue analyses in the experimental bins revealed increasing toxin accumulation over time, with concentrations reaching 41.0 ng/mL by week three, while water concentrations in experimental bins peaked at week two at 5.5 ng/mL. Toxins remained undetectable in both tissues and the water of control bins. These findings highlight that C. fluminea accumulate cyanotoxins. Behavioral suppression indicates physiological stress, shown by clams in the experimental bins opening less and taking longer to open, can have important ecological consequences. These behavioral changes reduce filtration rates, slow nitrogen regeneration, alter phosphorus cycling, and limit energy acquisition. Together, this suggests that the clams’ ability to carry out their natural ecological roles, including filtering the water and contributing to nutrient cycling, is compromised. This study underscores the ecological and public health significance of HAB exposure in freshwater ecosystems.

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