Plastic Waste Hosts Microbial Array

A surprising suite of microbial species colonizes plastic floating in the ocean and may speed the waste’s breakdown, according to a study (Environ. Sci. Technol. 2013, DOI: 10.1021/es401288x). Researchers, led by Linda A. Amaral-Zettler at the Marine Biological Laboratory and Tracy J. Mincer at Woods Hole Oceanographic Institution, analyzed plastic samples collected from the Atlantic Ocean. A centimeter-sized sample contained hundreds of microbial species distinct from those found in surrounding waters. Scanning electron micrographs show the bacteria lodged inside pits in the plastic. The team thinks that the bacteria eat into the polymers, weakening the pieces and possibly causing them to break down more quickly. Supporting this hypothesis, some of the plastic-burrowing bacteria are closely related to species known to consume other types of hydrocarbons, such as oil. Because plastic waste poses health risks to marine life, it would be promising to understand how microbes may break down plastics, says Michael Cunliffe of the Marine Biological Association of the U.K. But the process “needs to be shown in a bit more detail.”