What Forms of Pollution are Especially Harmful in Marine Ecosystems?

1. What Forms of Pollution are Especially Harmful in Marine Ecosystems? • Water Pollution: past belief that the ocean could dilute any amount of pollution (not true with persistent plastics and POPs) • Biomagnification: heavy metals and persistent organic pollutants (POPs) are difficult to metabolize and/or detoxify  concentrate in livers, fats of top predators (ex. DDT with egg-thinning effects  endangered bald eagles and pelicans); others weaken immune systems or cause feminization (ex. fish in Lake Mead); may lead to toxic red tides (POPs absorbed by phytoplankton) • Eutrophication and Sedimentation: excess plant nutrients lead to algal blooms; when algae die, leads to excess decomposition and thus high biological oxygen demand (BOD); can lead to fish kills and dead zones; excess sediment smothers corals and mucous-feeding invertebrates; treatment of sewage reduces both • Garbage: dumping in ocean outlawed in United States (Royal Caribbean fined $18 million in 1999; Navy exempt); plastics build up in central Pacific Ocean (center of gyre), eaten by loggerhead turtles (mistake for jellyfish); seabirds ingest and feel full, then regurgitate garbage to their offspring; hazardous waste includes radioactive materials and munitions • Responses: Clean Water Act (1972) regulates point sources (ex., known outfalls); Water Quality Act (1997) attempts to regulate non-point sources (ex., run-off)

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8. What Forms of Pollution are Especially Harmful in Marine Ecosystems? • Noise Pollution • Boat/ship traffic, Navy SONAR (incl. newer low-frequency type), ATOC controversy regarding measurement of Pacific Ocean warming vs. cetaceans (1996-2006) • Thermal Pollution • Coastal energy plants entrain seawater for cooling (lethal for many marine organisms), warm-water outflow harms some sessile organisms and may attract exotic species • Oil Pollution • Oil enters marine ecosystems via urban run-off, numerous shipwrecks (ex. Exxon Valdez in Alaska, 1989, 11 million gallons; Oil Pollution Act of 1990 calls for double-hulled tankers), cleaning of holds and transfer process; largest single events from offshore platforms (ex., BP Deepwater Horizon, 2010, 210 million gallons; Persian Gulf War, 250 million gallons purposefully released) • Crude oil separates into fractions (include known toxins and carcinogens; heavy elements smother benthic and intertidal organisms; floating fractions coat feathers of birds, coats of pinnipeds and sea otters (ingest in attempt to clean and can lead to loss of insulation; increase in pelagic tar balls noted between KonTikiand Ra expeditions of 1947 and 1968; evaporation leads to inhalation

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10. Are Introduced Species a Form of Pollution? • Exotic, non-native species (vs. indigenous species) • The only pollution that creates more of itself • Can be accidental (ex. ship ballast introduces marine species via larvae) or purposeful (ex. mongoose in Hawaii; many fishes) • Can have large effects on ecosystems since native species have not co-evolved competitive or anti- predation mechanisms • Main causes of species extinctions and endangerment in Hawaii and Puerto Rico (including many endemic species) • Often controversial regarding removal or treatment: poisoning of Lake Davis (CA) to remove pike; shooting goats on Catalina Island • Other examples: Africanized (“killer”) bees; brown tree snake (Guam); zebra mussels; “Med Fly”

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