By Max Liboiron.
You’ve probably heard of “The Great Pacific Garbage Patch” or “The Gyre,” or other names given to the phenomenon of ocean plastics. You may have asked yourself why we just don’t clean it all up with a giant sea-vacuum. You may have even seen inventions meant to do just that. But perhaps you have also heard from people and organization that have been working on the problem that the myth of clean up is a fallacy that fundamentally misunderstands the materiality of ocean plastics.
The vast majority of ocean plastics are less than five millimeters in size, called microplastics, and they are inextricable from the larger oceanic ecosystem. Plastics are dispersed unevenly both in terms of where they are in the water column, and where they are in each of the world’s five oceans, but in very few cases are they bunched up and scoop-able. Instead, they are within, and even constitute, ocean ecosystems. Animals as large as whales and as small as plankton ingest plastics as a matter of course (see image above). Microbes and mussels live on floating plastics. “Cleaning up” these plastics, even if it were technologically possible, would disrupt and destroy the ecosystems we would be trying to save in the first place.Some of these ecosystems are unique and exist only because of ocean plastics.
A new study published in Environmental Science and Technology has dubbed this uneven flotilla of plastic-based ecologies the “Plastisphere.” Using scanning electron microscopy and gene sequencing, the scientists found more than one thousand types of bacterial cells on ocean plastic samples. The tiny plastic pieces they investigated were home to plants, algae, and bacteria, animals and larger bacteria that feed on them, predators that feed on these, and other organisms that establish synergistic relationships. Some of these complex communities are the size of a head of a pin, matching the scale of their hosting microplastic. The report likens ocean plastics to “artificial microbial reefs” with more and different biodiversity than the surrounding sea water.
Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.
The Plastisphere is so named because the ecosystems on plastics are likely different from those that settle on naturally occurring floating material such as feathers or wood, because plastics offer different conditions, including the capacity to last much longer without degrading. Plastics have another unique feature: in addition to problems that arise from ingesting plastics, ocean plastics attract high numbers of water borne toxics. Microplastics can absorb more than one million times the level of toxicity of surrounding water, and are often nicknamed “poison pills” by scientists as a result. The Plastisphere is likely a highly toxic ecosystem. But it wouldn’t be the first time that unplanned toxic ecosystems have thrived. The Rocky Mountain Arsenal, sometimes called “The Most Toxic Mile in America,” was used first by the United States Army as a chemical weapons plant (and dump), and then by Shell Chemical Company to create (and dump) pesticides and herbicides. After Shell left the area, people stayed away from the toxic land for years, and as a result, many animals, including endangered species, made their homes there. The complexities of clean up at the Arsenal, now a National Park, are legion, as mandates not to disturb endangered species compete with regulations about the necessity of removing or containing toxic chemical sites.
Thus, waste ecosystems like the Plastisphere are not new. Industry has been using microbes to treat waste for more than a century in what are called “industrial ecosystems.” In 1989 in a Scientific American article by Robert Frosch and Nicholas E. Gallopoulos asked “why would not our industrial system behave like an ecosystem, where the wastes of a species may be resource to another species?” While the the authors were thinking more along the lines of intentionally designed industrial ecosystems such as those used today in sewage treatment plants, the unintentional example of the Plastisphere and the The Rocky Mountain Arsenal broadens the definition of industrial ecosystem to include unintentional systems, where the lines between desirable and undesirable, healthy and unhealthy, become blurred.
The industrial ecosystem closest to home is our own bodies. Body burdens refer to the industrial chemicals that accumulate in an animal’s tissues, including humans. The animals in the The Rocky Mountain Arsenal carry massive body burdens, but so do we. The last Center for Disease Control count has more than 98% of Americans carrying a body burden of over 100 industrial chemicals. Some chemicals are water soluble, like Bisphenol A (BPA), and they live in the body for around 6 hours. Other chemicals are not water soluble and accumulate in fatty tissue, like fire retardants, which are often found in household foams and other plastics. They stay with you for most of your life. Plastics are rarely, if ever, just made of plastic—they have chemicals called plasticizers in them– chemicals that are added to plastic to make it flexible or fire resistant or orange. These chemicals unbind from their host fairly easily. The scale of off gassing is so great that laboratory scientists have to come up with ways to determine the difference between the chemicals in their samples and the “background pollution” from the air in their labs and from their equipment. Even BPA, which leaves the body in about 6 hours, is always present in our bodies, meaning that sources are omnipresent. There is just no way to avoid a body burden, no way to “clean it up.” Our bodies are the newest sink in a long lineage of industrial ecosystems, and can even be considered an extension of the Plastisphere.
What do waste ecosystems like the Plastisphere, The Rocky Mountain Arsenal National Park, and our own bodies mean for notions of pollution as they pertain to harm and health? How do they complicate truisms of clean up and restoration? How do they expand the notion of industrial ecosystems as intentional versus unintentional, contained versus planet-wide? Most importantly, how do we re-conceptualize pollution when purity is no longer empirically possible? These questions are becoming more pressing as our current definitions of pollution, founded more than a century ago, are being outmoded by manifestations of pollution in the twenty-first century.
Centers for Disease Control and Prevention. “Fourth national report on human exposure to environmental chemicals.” National Center for Environmental Health, Division of Laboratory Sciences (2009).
Engler, Richard E. “The complex interaction between marine debris and toxic chemicals in the ocean.” Environmental Science & Technology 46.22 (2012): 12302-12315.
Frisch, R.A; Gallopoulous, N.E. “Strategies for Manufacturing.” Scientific American 261.3 (1989): 144-152.
Liboiron, Max. Redefining Pollution: Plastics in the Wild. (Doctoral Dissertation) New York University, 2012.
Mato, Yukie, et al. “Plastic resin pellets as a transport medium for toxic chemicals in the marine environment.” Environmental Science & Technology 35.2 (2001): 318-324.
Zettler, Erik Red, Tracy J. Mincer, and Linda A. Amaral-Zettler. “Life in the ‘Plastisphere’: Microbial communities on plastic marine debris.” Environmental Science & Technology (2013).
Max Liboiron is a postdoctoral researcher with the Intel Science and Technology Center for Social Computing and the Superstorm Research Lab.