When birds eat plastic that pollutes marine environments, they suffer a variety of debilitating health problems. Researchers have wondered why the animals are drawn to feed on ocean plastic, which doesn’t look like standard food. Now a team led by Gabrielle A. Nevitt and Matthew S. Savoca at the University of California, Davis, reports that plastic floating on the ocean surface is easily fouled by dimethyl sulfide-producing algae (Sci. Adv. 2016, DOI: 10.1126/sciadv.1600395). Birds in the Procellariiformes order, which includes petrels (shown) and albatrosses, use the aroma of dimethyl sulfide as a dinner cue signaling that there’s nutrient-rich food nearby. So when fouled ocean plastic debris smell of dimethyl sulfide, these birds are drawn to consume it.
The team tested 4- to 6-mm-diameter plastic beads made from common plastic polymers—namely high-density polyethylene, low-density polyethylene, and polypropylene. After being stored in ocean water, the plastic debris developed algal films and an aroma of dimethyl sulfide within a month at levels several orders of magnitude higher than the birds’ detection threshold.
The results “point to remediation strategies, including increasing antifouling properties of consumer plastics,” note the researchers, especially because other marine organisms also use dimethyl sulfide as a dinner cue.