Filter Feeding Simulation Reveals a Pathway for Microplastic Consumption in Baleen Whales
Abstract/Description/Artist Statement
Microplastics (MPs) are a ubiquitous pollutant in marine environments. MPs have been found in the feeding grounds and in the tissues of several rorqual whale species (Balaenopteridae, Mysticeti) such as fin, humpback, and minke whales. Current research suggests that a majority of MP consumption by rorquals is an indirect result of trophic transfer. However, the prevalence of MPs in rorqual foraging areas combined with their filter feeding behavior suggests that they may ingest waterborne MPs directly from the water. To test this hypothesis, we developed a physical model based on a humpback whale baleen rack and inserted it into a flume tank. We adjusted the water velocity in the flume to mimic humpback filter feeding in vivo, and released polyethylene beads (355 um and 600 um) and polyethylene terephthalate fragments (435 um and 1 mm) upstream of the model in high and low doses. After a precalculated filter time, we collected the MPs with an underwater vacuum and sieve, and quantified them using a stereomicroscope. Our results illustrate that 1.35-20.9% of MPs are captured by the baleen rack during a single humpback feeding event. Additionally, we found that size significantly impacts retention by the baleen rack, regardless of polymer type and dose, with larger particles retained more than smaller particles. This information is essential to understanding baleen function, improving calculations estimating rates of MP consumption, and provides context to the potential health impacts these species face.
Faculty Advisor/Mentor
Shirel Kahane-Rapport
Faculty Advisor/Mentor Email
skahaner@odu.edu
Faculty Advisor/Mentor Department
Department of Biological Sciences
College/School Affiliation
College of Sciences
Student Level Group
Graduate/Professional
Presentation Type
Oral Presentation
Filter Feeding Simulation Reveals a Pathway for Microplastic Consumption in Baleen Whales
Microplastics (MPs) are a ubiquitous pollutant in marine environments. MPs have been found in the feeding grounds and in the tissues of several rorqual whale species (Balaenopteridae, Mysticeti) such as fin, humpback, and minke whales. Current research suggests that a majority of MP consumption by rorquals is an indirect result of trophic transfer. However, the prevalence of MPs in rorqual foraging areas combined with their filter feeding behavior suggests that they may ingest waterborne MPs directly from the water. To test this hypothesis, we developed a physical model based on a humpback whale baleen rack and inserted it into a flume tank. We adjusted the water velocity in the flume to mimic humpback filter feeding in vivo, and released polyethylene beads (355 um and 600 um) and polyethylene terephthalate fragments (435 um and 1 mm) upstream of the model in high and low doses. After a precalculated filter time, we collected the MPs with an underwater vacuum and sieve, and quantified them using a stereomicroscope. Our results illustrate that 1.35-20.9% of MPs are captured by the baleen rack during a single humpback feeding event. Additionally, we found that size significantly impacts retention by the baleen rack, regardless of polymer type and dose, with larger particles retained more than smaller particles. This information is essential to understanding baleen function, improving calculations estimating rates of MP consumption, and provides context to the potential health impacts these species face.