Macrofouling Settlement on Commercial Plastics

Globally, 8 million metric tons of plastic makes its way to the oceans annually. With plastic comes open surface area for macro-fouling organisms to settle upon. Where literature stands now, there is a story of succession for these settlers. The succession story is that settlement starts with a molecular film, then bacteria settle in the first week or so, and then by 4-6 weeks the macrofouling organisms begin to settle and grow. This study aimed to change the narrative of this succession story to say that many macrofouling organisms in the biofouling community settle as, or more, quickly than bacteria and are actually reproducing in less than a month. The other message is that plastics are dynamic surfaces and communities on these surfaces vary with plastic type over time. Using commercial plastics, we show that settlement of macrofouling organisms happens in hours to days, rather than 4-6 weeks. Three major fouling animals are reproductive on plastics immersed for less than a month. The communities on the different single use plastics are not the same after 30 days and some of these differences related to surface energy and to molecules added to plastics for processing that leach out and change over time. This research is a step towards a more accurate story of macrofouling settlement on plastic surfaces.