Kareiva: Marine Pollution and a World of Waste


I was just revising the “marine chapter” for a textbook I have coauthored, and looking at reviews from professors who had taught a conservation course using our first edition. We were criticized for making marine conservation too much about fishing and marine protected areas, while neglecting ocean pollution as a big deal, and probably the greatest threat to our oceans.

It turns out these critics were right.

For much of human history the ocean has been viewed as a place to dispose of waste where it would be so diluted that it does no harm. We now know better.

Dead zones, floating mats of plastics, and toxic chemical residues in marine fish tissue are striking evidence that human waste and by-products could be every bit as much of a threat to our oceans as over-fishing.

Dead zones now affect more than 400 systems, and cover vast areas of the ocean — more than 475,000 square kilometers. Plastic debris in the oceans is now so common it is hard to find a beach without washed up plastics. This plastic is much more than a matter of aesthetics; all sea turtles, 45% of marine mammals, and 21% of seabird species are harmed by plastic.

The sheer volume of human waste products and the fact that most people live along coasts means that there will be no simple, single measure that can address marine pollution.

Take something as specific as cigarette butts — over 4.5 trillion cigarette butts are discarded annually, and researchers have observed a 96-hour mortality effect (measured as LC-50) in larval topsmelt (a Pacific ocean silverside) at a dilution of one cigarette butt per liter of water. Latte-drinking enthusiasts in my hometown of Seattle have given rise to elevated caffeine concentrations in Puget Sound, which are known to cause chemical stress in mussels and other marine invertebrates.

So what are we to do?

There are solutions — but they are not things conservationists typically write about, or lobby for. Take plastic. Because it is so hard to eliminate the discarding of plastics, a better approach may well be the design and production of biodegradable plastics, which do not persist long in the ocean.

Microbes have been genetically engineered to produce biodegradable plastics, and this new technology could be hugely beneficial to the world’s oceans. But bioplastics generated by GMO microbes will never be commonplace if certain environmental activists succeed in scaring the public away from all forms of genetic engineering.  A less innovative approach entails investing in expensive tertiary treatment (when much of the world does not even have primary treatment of waste), and green chemistry approaches, which may be able to design less toxic or persistent compounds. 

It should be feasible to generate political will for addressing marine pollution because doing so would benefit human health as well as biodiversity. Even low levels of mercury are so toxic to infants that curtailed fish consumption is advised in many countries due to the ubiquity of mercury in the environment.

Again this is a problem that could be solved, since we know where mercury comes from and we know how to reduce its emissions. The problem is cost and tradeoffs. Mercury emissions from coal smoke are the primary anthropogenic source, but additional sources include some cosmetics, some pharmaceuticals, and dental products.

Conservationists talk a lot about consumption, and are well aware of the harm that can be done due to resource extraction. With greenhouse gases causing climate change, we also have a growing appreciation of the “emissions problem.” But the emissions problem is not just about greenhouse gases. Our tendency to discard and emit in huge volumes demands that we invest in new technologies that can solve the pollution problem. If we fail — all of the marine protected areas in the world will make no difference.



Church, G and E. Regis. 2012. Regeneis: How Synthetic Biology Will Reinvent Nature and Ourselves. Basic Books.

Derraik, J. 2002. The pollution of marine environment by plastic debris. Marine Pollution Bulletin 44: 842-852.

Mearns, A. et al. 2012. Effects of pollution on marine organisms. Water Env. Research. 84: 1737-1798.

Rochman et al. 2013. Classify plastic waste as hazardous. Nature 494:169-171.

Zahir, F. et al. 2005. Low does mercury toxicity and human health. Env. Toxicology and Pharmacology

Photos: Beach litter by T3rminatr in public domain. Dead albatross by U.S. Fish and Wildlife Service.

Opinions expressed on Cool Green Science and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy.

Posted In: Birds, Coral Reefs, Science

Peter Kareiva is chief scientist at The Nature Conservancy, where he is responsible for developing and helping to implement science-based conservation throughout the organization and for forging new linkages with partners.

In addition to a long academic career, he has worked at the National Oceanic and Atmospheric Administration (NOAA) and directed the Northwest Fisheries Science Center Conservation Biology Division. His current projects emphasize the interplay of human land-use and biodiversity, resilience in the face of global change, and marine conservation.

Comments: Kareiva: Marine Pollution and a World of Waste

  •  Comment from Jim


    In this and other writings, you display a strong tendency to assume that because TNC does not work on an issue, that few environmental groups work on it either. Thus you inadvertently come off as sounding disconnected from what others are working, excessively focused on presenting your ideas as “new”, and needlessly antagonizing others.

    MERCURY. NRDC, Sierra Club, National Wildlife Federation, Center for Biological Diversity, Environmental Defense Fund, Wild Earth Guardians and many regional groups have extensive and successful programs fighting mercury emissions from coal-fired power plants. It’s about as mainstream as it gets.

    DEAD ZONES. Massive state, federal and NGO energy has gone into reducing agricultural runoff contributing to dead zones, especially in the Gulf of Mexico and Chesapeake Bay. I would hazard to guess investment on these programs runs near to a $100 million per year.

    PLASTICS. Less has been done in this area because it has only been in recent years that scientists have begun to document the extent and impact of marine plastics. Indeed, it is still a rapidly developing field of knowledge and we’re still quite short on knowledge about the effects of micro-plastics on wildlife. Nonetheless, the Center for Biological Diversity is pushing to declare certain garbage patches as federal superfund sites and there is an environmental coalition working to educate the public and decision-makers and increase funding for additional research. As I’m sure you know, the idea of introducing plastic-consuming GMOs is controversial, and not just among “certain activists.” Most scientists and agencies believe that we are far from knowing enough about such organisms to introduce them into the environment at a scale sufficient to address such a massive source of pollution. You’d do better here, to discuss the pros and cons and describing the state of the research and discussion, rather than attacking unnamed “activists” while giving the impression that your proposal is not controversial.

    MARINE PROTECTED AREAS. While I appreciate your call for more work on marine pollution, it is gratuitous and counter-productive to pit this work against establishment of marine protected areas. This is another trend in your recent writings: falsely pitting protected area work (parks, wilderness, marine reserves, etc.) against other kinds of work you deem (mostly falsely) to be “new” approaches. We need to do both. If we fail at one, it does not eliminate the value of the other.

    In short, here and elsewhere you point out important problems and suggest interesting solutions. But your rhetorical instinct to present your ideas of “new”, contrast them to what other conservationists are doing makes, and ignoring the work of others comes off as disconnected and somewhat egotistical. It also likely drives away many of the people you are seeking to communicate with. You’ll do more good by ramping up the information and toning down the rhetoric.

  •  Comment from Jeremy

    Dr. Kareiva certainly likes to play the contrarian. I suppose he finds it boring to “merely” contribute to the ongoing work of a community of researchers and conservationists.

  •  Comment from Carson Parmenter

    My question is, after learning what marine pollution does to the beaches and our marine mammals, what does it do to the marine environment as a whole?

  •  Comment from Sierra

    Let’s not tale this against the author, guys. We are being informed of the harm the all the risks our marine life is facing due to our irresponsible waste disposal.

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