Investigators: Dr. Leigh Torres, Dr. Kim Bernard, Dr. Susanne Brander, Dr. Sarah Henkel, Lisa Hildebrand
Microplastics are barely visible (< 5mm) forms of plastic including small fragments, fibers, and granules, that enter the marine environment via ineffective removal during wastewater and storm water treatment, or are produced via the gradual breakdown of larger plastic items (e.g. plastic bags, fishing nets). Microplastics are the most abundant type of synthetic marine debris in coastal and open-ocean marine environments, found in surface waters, throughout the water column, and in sediments. Although microplastics have been documented in Oregon coastal organisms (e.g. rockfish, bivalves) the magnitude of the problem has not been quantified, particularly in zooplankton that serve as the base of the coastal food web. Marine zooplankton ingest microplastics that are mistaken for food, which raises concerns for higher trophic level species that consume zooplankton and may bioaccumulate the plastics and adhered toxins.
Zooplankton in coastal Oregon are primary prey for multiple important commercial and recreational fisheries, such as groundfish and salmon, and are the target prey of foraging gray whales, which support valuable coastal tourism industries. As filter-feeding animals with large appetites for zooplankton, whales are particularly susceptible to high levels of microplastic ingestion, as evidenced by documentation of microplastics in the intestines of baleen whales. These fish, fisheries, and whales all have high cultural and economic importance to tribes, residents, and visitors to the Oregon coast, yet the impacts of microplastics via their zooplankton prey base are largely unknown. Potential health impacts to marine organisms from microplastics include consumption of indigestible particles that block adequate nutrient absorption, mechanical damage to the digestive tract, and absorption of toxins.
COZI is a cross-college collaborative effort led by four early-career female scientists that aims to improve our understanding of microplastics in coastal Oregon zooplankton by species, life history stage, location, and time. Dr. Torres studies the foraging ecology of gray whales along the Oregon coast, including collection of zooplankton samples to assess prey availability. Preliminary analyses of these samples have included community analysis through species identification led by Dr. Henkel, and bomb calorimetry of zooplankton, led by Dr. Bernard, to determine the energetic value to predators. We are now linking with Dr. Brander’s research on microplastics in Oregon groundfish to assess microplastic loads at the base of the food web. Preliminary results from this work demonstrate that 20% of black rockfish caught off the Oregon coast ingest suspected plastics. Analyses (conducted in collaboration with the gray whale foraging ecology project) include species identification, caloric content determination, and microplastic quantification and identification.
Hildebrand, L., Bernard, K. S., & Torres, L. G. (2021). Do Gray Whales Count Calories? Comparing Energetic Values of Gray Whale Prey Across Two Different Feeding Grounds in the Eastern North Pacific. Frontiers in Marine Science, 1008.
Do gray whales count calories?
Plastics truly are ubiquitous in the marine environment
Robyn Norman, Benthic Ecology Lab, Oregon State University
Oregon State University Agricultural Research Foundation