Scientists at Australias University of New South Wales and Commonwealth Scientific and Industrial Research Organization have recently discovered that a catastrophic tipping point may soon be reached causing severe ocean acidification to occur. Rising carbon dioxide levels quickly increase the volume of dead zones in oceans. Global atmospheric levels of CO2 are currently estimated at 385 parts per million (ppm). Researchers state that we are quickly approaching the 450 ppm level of CO2 that would drastically affect oceanic organisms. A loss in oceanic organisms would render the oceans unable to effectively absorb carbon. This would in turn lead to an exponential increase in global warming. Save our Oceans. Save our Planet.Be Veg. Go Green. Reference Creeping Dead Zones (NASA - 19 Feb 2009) America's Meat Habit Feeds Gulf Dead Zone (Discovery News - 18 Dec 2008) Space scientist warns: climate 'tipping point' is near (peopleandplanet.net - 27 Jun 2008) America's Animal Factories :How States Fail to Prevent Pollution from Livestock Waste (Natural Resources Defense Council ) One third of fish caught worldwide used as animal feed (Telegraph - 29 Oct 2008) Half Of US Coral Reefs In 'Poor' Or 'Fair' Condition, NOAA Report States (ScienceDaily - July 9, 2008) Half of all coral reefs in danger, experts warn (MSNBC - Oct. 25, 2005) Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia (Geological Society of America - May 2005) Hydrogen Sulfide Eruptions Along the Coast of Namibia (NASA - May 2004) Hydrogen Sulfide, Not Carbon Dioxide, May Have Caused Largest Mass Extinction (ScienceDaily - 5 Nov 2003) Creeping Dead Zones This is not the title of a sequel to a Stephen King novel. "Dead zones" in this context are areas where the bottom water (the water at the sea floor) is anoxic — meaning that it has very low (or completely zero) concentrations of dissolved oxygen. These dead zones are occurring in many areas along the coasts of major continents, and they are spreading over larger areas of the sea floor. Because very few organisms can tolerate the lack of oxygen in these areas, they can destroy the habitat in which numerous organisms make their home. The cause of anoxic bottom waters is fairly simple: the organic matter produced by phytoplankton at the surface of the ocean (in the euphotic zone) sinks to the bottom (the benthic zone),where it is subject to breakdown by the action of bacteria, a process known as bacterial respiration. The problem is, while phytoplankton use carbon dioxide and produce oxygen during photosynthesis, bacteria use oxygen and give off carbon dioxide during respiration. The oxygen used by bacteria is the oxygen dissolved in the water, and thats the same oxygen that all of the other oxygen-respiring animals on the bottom (crabs, clams, shrimp, and a host of mud-loving creatures) and swimming in the water (zooplankton, fish) require for life to continue. The "creeping dead zones" are areas in the ocean where it appears that phytoplankton productivity has been enhanced, or natural water flow has been restricted, leading to increasing bottom water anoxia. If phytoplankton productivity is enhanced, more organic matter is produced, more organic matter sinks to the bottom and is respired by bacteria, and thus more oxygen is consumed. If water flow is restricted, the natural refreshing flow of oxic waters (water with normal dissolved oxygen concentrations) is reduced, so that the remaining oxygen is depleted faster. Many of the areas where increasing bottom water anoxia has recently been observed are near the mouths of major river systems. While the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) cant see the bottom of the ocean, it can see the surface, where sediments from rivers mix with ocean waters. The images shown here are SeaWiFS observations of the Mississippi River delta, the Yangtze River mouth in China (The Yangtze River mouth is not currently identified as an area with an associated dead zone, but such conditions could develop there in the future), and the Pearl River mouth in China, near Hong Kong.

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