ASLO Raymond L. Lindeman Award: Dissolved Organic Carbon Leaching from Plastics and its Impact on Microbes in the Ocean (Cristina Romera-Castillo)

This award was first presented in 1987 to recognize an outstanding paper written by a young aquatic scientist. The paper for which Raymond L. Lindeman is remembered, published posthumously in 1942, has since become the foundation for research on the flow of energy in plant and animal communities.

Abstract: More than 5.25 trillion of plastic pieces have been estimated to be floating at the sea surface. Plastic marine debris on beaches and floating in seawater is exposed to solar UV radiation undergoing weathering degradation. It can develop surface cracks and fragment into progressively smaller particles reaching microscopic sizes (< 5 mm, microplastics). Detrimental effects of plastics on marine organisms at different trophic levels have been widely reported, making plastic pollution a global environmental concern. Plastic is known to leach organic compounds to the aquatic media. The smaller the piece, the higher its surface to volume ratio and its potential for leaching. However, the contribution of plastic leaching to the dissolved organic carbon (DOC) pool in the ocean and its impact on the lowest trophic levels, such as the microbial food web, was still unknown. Here, I will show experimental evidence that plastics release dissolved organic carbon (DOC) into the ambient seawater stimulating the activity of heterotrophic microbes. It is predicted that plastic waste entering the ocean will increase by 10-fold over the next decade, resulting in an increase in plastic-derived DOC that could have unaccounted consequences for the activity of marine microbes and for the ecosystem.