Microplastic Abundance in Agglutinated Benthic Foraminifera in the Gulf Of Mexico

Plastic pollution in the marine environment is a growing concern that can threaten marine organisms and move up the food chain to accidental human consumption. Microplastics (<5 mm) are formed due to the degradation of plastics caused by wave action and UV radiation. Although plastics are produced on land, studies have suggested that turbidity currents transport microplastics and other sediments down slope and into deep-sea environments.  Agglutinated benthic foraminifera, who live in such environments, use sediments to create tests (shells), causing microplastics within sediments to become incorporated into their tests. This study examines the abundance of microplastics within deep ocean sediments in the Gulf of Mexico to understand how the abundance of microplastics changes over time and based on geologic location. Samples were collected in July 2017 at three sites in a transect from the Desoto Canyon to the West Florida Shelf of the Gulf of Mexico. The top samples (modern sediments) and 100 mm downcore (sediments before plastic contamination to the ocean) were stained with Nile Red so that plastics would fluoresce under cyan light. The westernmost site (Desoto Canyon) contained the highest plastic abundance. Plastic abundance decreased along the transect with the lowest in the West Florida Shelf sediment, supporting the theory that plastics are transported down marine canyons to the deep sea. Plastics found in downcore samples are likely linked to bioturbation. This research can help determine if microplastics exist in deep-sea sediments better to understand the impacts of humans on deep-sea environments. 

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