San Francisco State University Hayward, California, United States
Background/Question/Methods
Microplastics are ubiquitous throughout the Pacific Ocean, and are considered a threat to filter feeding animals. For example, microplastics can cause mortality and reproductive decline when consumed by Pacific Mole Crabs (Emerita analoga). Whether microplastics induce behavioral changes in nature, has yet to be determined. We hypothesized that microplastic ingestion and temperature influence burrowing behavior. To study burrowing behavior, we developed assays to quantify burrowing speed and depth. We then examined if their burrowing speed was impacted by an increase in temperature or plastic ingestion as indexed by plastics in fecal pellets. Crab individuals of varying body size, sex and reproductive state were assayed during summer-autumn 2021 at Fort Funston, San Francisco.
Results/Conclusions
Average burrowing time was 11.1 seconds and average burrowing depth was 0.29 inches. The average water temperature for this experiment was 17.9℃. Crab size and sex were not related, but burrowing depth lessened with repeated trials on the same individual. After laboratory analysis, crabs with higher number of ingested microplastics dug slower and shallower than those with a lower number of ingested microplastics. These data will be used to further explore the likely ecological impacts of warming and microplastics on sandy beach ecosystems.
