URIs_MOMENTUM_Research_and_Innovation_Magazine_Spring_2021_M

MICROPLASTICS:

HOW ARE THEY IMPACTING THE BACTERIA IN THE FOOD CHAIN?

written by ALLISON FARRELLY ’16

Photo by Jason Jaacks

Anubhav Tripathi at Brown University, funded by a grant from the Rhode Island Science and Technology Advisory Council, have recently published their findings in two articles 1 . At less than a single millimeter in length and thinner than human hair, most microplastics are undetectable to the human eye. Many commonly used plastics sink in ocean water, and they encounter a variety of species in the water column. To bacteria, a crucial player in fragile aquatic ecosystems, these sinking particles are foreign objects. “If you disturb an ecosystem by doing something to these bacteria, it has implications that go far beyond the bacteria,” Bose said. His lab began by looking at how cyanobacteria, which regulates ocean nitrogen levels, interact with microplastics. “This is a very, very important part of the food chain,” Bose explained. “As a disturbance in nitrogen levels can decimate larger species starting with their food source, phytoplankton. “Bacteria are living beings, and they are extremely smart. If you expose them to something that is foreign to them, you can expect that biologically, they are going to do something that will help them face the new stressors.”

University of Rhode Island (URI) Distinguished Engineering Professor Arijit Bose was flipping through a magazine when a disturbing statistic caught his eye — by the year 2050 there will be more plastics than fish in the ocean. This environmental crisis has garnered enormous publicity in recent years. The term “ocean plastics” invokes arresting images of miles-wide patches of debris floating in the Pacific Ocean, plastic melting out of Antarctic ice, a grocery bag on the bottom of the deepest ocean on Earth, the South Pacific’s Mariana Trench, and turtles entangled in six pack holders and discarded fishing gear. With the COVID-19 pandemic, the waste can mean discarded surgical masks outnumbering jellyfish. As Bose examined what expertise he could lend to fixing this problem, he noticed an incredibly small organism with a big impact on the food chain that was being overlooked: bacteria. When he looked closer, he found that bacteria already might be working to rid the ocean of plastic particles. His research group, in collaboration with that of Professor

1 (i) Interaction of Cyanobacteria with Nanometer and Micron Sized Polystyrene Particles in Marine And Fresh Water, T. T. S. de Oliveira, I. Andreu, M. C. Machado, G. Vimbela, A. Tripathi, A. Bose, Langmuir , 36, 3963-3969 (2020).

(ii)The Response of Synechococcus sp. PCC 7002 to Microplastic Polyethylene Particles - Investigation of a Key Anthropogenic Stressor, M. C. Machado, G. V. Vimbela, T. T. S. de Oliveira, A. Bose, A. Tripathi, PLOS One 15, E0232745 (2020).

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