Award: OCE-1155671

Plastic has become the most common form of marine debris in the 60 years since it entered the consumer arena and presents a major and growing pollution problem (Laist, 1987; Derraik, 2002; Andrady, 2011).  The current global annual production of 245 million tons (Andrady, 2011) represents 35 kilograms of plastic produced annually for each of the 7 billion humans on the planet.  Drifter buoys and physical oceanographic models have shown that plastic can migrate over 1000 kilometers, from Eastern Seaboard locations to the interior of the North Atlantic Subtropical Gyre (NASG), in less than 60 days (Law et al., 2010).  Plastic debris in the NASG (Law et al., 2010) and North Pacific Subtropical Gyre (NPSG) is well documented (Moore et al., 2001; Pichel et al., 2007; Moore, 2008) and mathematical models and sampling confirm that accumulations of plastic marine debris have formed in all five of the world’s subtropical gyres, (Barnes et al., 2009). Once trapped in central ocean gyres, there are very few avenues for export, and plastic particles can concentrate and persist for many years.

Plastic debris provides a substrate for marine life that lasts much longer than most natural floating substrates and has been implicated as a vector for transportation of harmful algal species (Maso et al., 2003) and persistent organic pollutants (POPs). Typically of a hydrophobic (oily) nature, POPs stick, or sorb onto plastic (Hirai et al., 2011).  Plastic debris, itself, is also hydrophobic and can rapidly stimulate biofilm formation in the water column, functioning as an unnatural “microbial reef” substrate. 

Our results indicate microplastics contain distinct microbial communities compared to seawater on both local and regional scales.  Additionally, biomarker analyses reveal a "core" taxa that appear to define different polymer types.

Outcomes from this research funded by this National Science Foundation Collaborative Research Program include: data showing that marine plastic debris supports a diverse array of microbial life, including a possible mechanism for microbially-mediated degradation (Zettler, et al., 2013); research showing that microflora of plastic debris in the marine environment displays a distinct biogeography, an important point for policy makers with concerns of invasive microbial species (Amaral-Zettler, et al., 2015 accepted); a review outlining microbial interactions with plastic marine debris (PMD) that has been accepted for publication as a book chapter (Mincer, et al., 2015); and a research report that is currently in preparation detailing genomically informed adaptations of Vibrio spp. that inhabit PMD. Overall, our research suggests that the response of microbial communities to plastic debris in the oceans appears to posess subtle but additive effects that have the potential to shift major biological processes on Earth.

Summary of other Project Outcomes:

• >2000 cultures isolated from PMD, Sargassum seaweed, invertebrate larvae and seawater spanning Proteobacteria, fungi, and diatom phylogenetic backgrounds.These cultivars are all isolated to purity and cryopreserved in our culture collection.
• 7 high school students, 1 REU, 2 WHOI guest students, and 1 guest investigator have been trained under this grant.
• PI Mincer has presented 5 invited talks on this research at top-tier universities around the Country, additionally PIs Mincer, Zetter and Amaral-Zettler were Co-session organizers and Co-chaired a session on plastic marine debris at the ASLO Ocean sciences meeting, 2014.
• Over 50 popular media products have covered research from this grant, including: magazine articles, radio interviews, television interviews, and documentaries.

References:

1. Amaral-Zettler, L. A.*, Zettler, E. R., Slikas, B., Boyd, G. D., Melvin...