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Coral reef attributes associated with microplastic exposure
Citation:
Hankins, C., D. Lasseigne, S. Davis, K. Edwards, AND J. Paul. Coral reef attributes associated with microplastic exposure. CORAL REEFS. Springer, New York, NY, 44(1):193-207, (2024). https://doi.org/10.1007/s00338-024-02596-4
Impact/Purpose:
Microplastics, defined as plastics <5 mm, are an emerging threat to stony coral and have been shown to have adverse effects on coral in laboratory studies. With an estimated 3% of plastic produced annually (approximately 12 million tonnes) entering the marine environment, additional research is needed to better predict microplastic impacts on coral. Subsurface water samples (3 m depth) and coral tissue samples were collected in conjunction with the National Oceanic and Atmospheric Administration's (NOAA) National Coral Reef Monitoring Program (NCRMP) in St. John, USVI and Florida's Coral Reef. Using EPA's Coral Reef Biological Condition Gradient (BCG) the data from the NCRMP surveys were used to establish BCG levels at specific reef sites. Microplastic concentrations were determined in the water and coral tissue samples. Correlations were investigated to determine any causal factors with microplastic concentrations and reef health. The use of the BCG could be an excellent tool in exploring impacts of individual stressors and identify significant threats to coral reef ecosystems. This is the first study to use the BCG in this way to determine interactive effects of microplastics on reef health. Additionally, this is first study to measure microplastic concentrations in coral in either USVI or Florida's Coral Reef.
Description:
Coral reef declines have been documented since the 1980’s from a variety of global and local stressors. Management resource tools are needed to preserve these fragile ecosystems from stressors, both known and unknown. Laboratory studies have shown microplastics (MP) to have negative effects on coral physiology, but their effects in a natural environment are not well understood. Thus, our primary objectives were to explore associations between MPs and coral reef attributes. We measured MP concentrations from sub-surface water and coral tissue samples from two Caribbean/Atlantic scleractinian coral species, Montastraea cavernosa and Orbicella faveolata, from St. John, U.S. Virgin Islands and Florida’s Coral Reef in 2017 and 2018, respectively. Polymer identification yielded mostly cotton or polyester fibers for both water and coral tissue samples. This study is the first to document MPs in coral tissues from either the U.S. Virgin Islands or Florida’s Coral Reef and is the first to explore how MPs relate to coral reef attributes. Significant, positive relationships were seen between MPs in coral tissue and coral density, rugosity, and percent coral cover, indicating MPs may not have immediate adverse effects on coral reef health.
