Tons of plastic floats in the oceans, and it's covered in microscopic life. But a new study reveals plastic-loving species that have never been seen before, and ecosystems entirely new to science. Say hello to life in the 'plastisphere.'
For the study, which now appears in Environmental Science and Technology, researchers Tracy Mincer from the Woods Hole Oceanographic Institution in Massachusetts and Linda Amaral-Zettler of the Marine Biological Laboratory in Woods Hole, used fine mesh nets to collect pieces of plastic ranging in size from 1-5 mm in diameter from multiple locations in the North Atlantic Ocean.
After analyzing the microbes with scanning electron microscopy (SEM) and next-generation genetic sequencing, the researchers discovered a diverse community of heterotrophs (organisms that feed off of complex organic substances), autotrophs (organisms that feed off simple inorganic substances like carbon dioxide), predators, and symbionts. It's a a rich and dynamic ecosystem they're now calling the plastisphere.
And in fact, the plastic communities were more diverse — and isolated — from those in other seawater samples (which are typically dominated by only a few species). Over 1,000 species were discovered, including plants, algae, and bacteria (some of which are still unidentified).
The researchers say that the plastic is acting as a veritable reef onto which the microbes are clinging. These "microbial reefs" are offering a distinct place that selects for and supports advantageous microbes to settle, succeed — and evolve.
Fascinatingly, the researchers discovered so-called "pit formers" in the microbial mix — organisms that were found on certain types of resins that are actually breaking down (i.e. eating) the plastic. So it's possible that some of this plastic — which has a longer half-life than most natural floating marine substrates — is actually being degraded at a rate faster than we thought.
Read the entire study at Environmental Science and Technology: "Life in the "Plastisphere": Microbial Communities on Plastic Marine Debris."
Image: Zettler et al/Environmental Science and Technology.