Sunday, September 14, 2008

World's oceans could become "soupy swill": expert

Times Colonist (Canada): …Our seas are suffocating under a layer of slime. That slime - algae feasting on pollutants and fertilizers and starving the ocean of oxygen - is growing rapaciously and killing off sea life at an alarming rate. These toxic "dead zones" have been spreading up the Pacific Northwest coast.

Since 2002, Oregon's waters have seen yearly species die-offs due to hypoxia (low-oxygen) and anoxia (no-oxygen) conditions from nutrients in currents and algae blooms. A new study published in August reveals the world's dead zones have doubled in size every decade since 1960. Coastal waters with once rich marine life - Chesapeake Bay, the Baltic Sea, the Black Sea and off Peru, Chile and Namibia - are rapidly losing species.

According to the report by two U.S. scientists, Spreading Dead Zones and Consequence for Marine Ecosystems, there are 405 asphyxiating dead zones in our oceans. At this rate, one B.C. scientist says, all that will be left for the next generation to harvest from the sea is "plankton soup."

The crisis is of our own making. The cause, predictably, is pollution. The culprits are fertilizer runoff in estuaries, sewage, global warming, overfishing and industrial waste. Millions of tonnes of "nutrient pollution" - chemical fertilizer that adds phosphates and nitrogen to the water - feed algae blooms.

…Diaz calls the trend a "widespread deleterious anthropogenic influence on . . . marine environments" that "rank[s] with overfishing, habitat loss and harmful algal blooms as major global environmental problems."

…Jeremy Jackson, a Scripps Institution of Oceanography professor, released a report in August warning of "mass extinction in the oceans" due to dead zones, global warming, overfishing, pollution, ocean acidification, ecosystem destruction and invasive species. "Coastal ecosystems are endangered to critically endangered on a global scale," he states, and "unrestrained runoff of nutrients and toxins, coupled with rising temperatures, will increase the size and abundance of dead zones and toxic blooms that may merge along all continents."

Photo of green algal growth (Enteromorpha sp.) on rocky areas of the ocean intertidal shore, indicating a nearby nutrient source (in this case land runoff). Photographed by Eric Guinther near Kahuku, O‘ahu, Hawai‘i, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2

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