"All the plastic types harbored diatom communities because the plastics are like tiny reefs that provide surface for the diatoms to grow on," said Neuer, senior principal investigator and researcher with the Biodesign Institute's Center for Fundamental and Applied Microbiomics. "It was interesting that we found significant differences in the diatom communities on the different plastic types, and some diatoms were unique to certain plastic types.

"Knowing how these plastic-adhered communities differ as a result of plastic polymer type has some interesting consequences," Neuer said. "It turns out that certain bacteria are associated with these diatoms, and those are capable of degrading plastic or other environmental contaminants associated with plastics. If certain diatoms are exhibiting a preference for certain plastic types, they may also selectively recruit these contaminant-degrading bacteria to the plastics’ surface, which might enhance the plastic’s degradation." 

"I wish to further explore this diatom-hydrocarbon degrading bacteria relationship and assess whether diatoms help to recruit hydrocarbon degrading bacteria to a plastic's surface," Dudek said.

Dudek speculated that microplastics could also serve as a vehicle for toxic and disease-causing organisms. These contaminated microplastics could potentially be dragged from the coasts to the open oceans via currents, to be swallowed by fish or sink and affect the benthic communities on the ocean floor, but much research remains to be done regarding the role microplastics play in the transportation of pathogens.

"Only about 1% of marine plastic debris is recovered at the ocean's surface, meaning the other 99% likely either sinks or is consumed by marine organisms," Dudek said. "I am currently exploring the role microplastic biofilms have in a microplastic's degradation and sinking capacity in different marine environments."

This is the first study of its kind carried out in the coastal waters of Panama.

The research findings are published in Limnology and Oceanography Letters.

Members of the research team are affiliated with ASU's School of Life Sciences, ASU Biodesign Institute's Center for Fundamental and Applied Microbiomics, and the Smithsonian Tropical Research Institute. Research was funded by United States Agency for International Development (USAID) Global Development Research program.

In 2009, the Smithsonian Institution joined ASU in an innovative education and science partnership aimed at sustaining biodiversity on Earth. This affiliation was created to acquire and share technology, education and outreach, and interdisciplinary research innovations in: social systems; ecosystem services; sustainability; biodiversity and genetics; and alternative energy. The School of Life Sciences leads this endeavor with the Smithsonian Tropical Research Institute in Panama.

Sandra Leander

Assistant Director of Media Relations, ASU Knowledge Enterprise