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.
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