Gulf of Mexico Dead Zone
Image credit: NOAA via Science Daily
American farmers love their chemical fertilizers and pesticides, and apply them liberally to their crops. Unfortunately, these chemicals – along with nitrogen-rich livestock waste – seeps from farmlands along the Mississippi River into the water and eventually, down into the Gulf of Mexico, where they have led to an oxygen-starved “dead zone” the size of New Jersey. Ocean dead zones cannot support sea life.
Nitrogen in the chemicals and animal waste spur the growth of algae, which is eaten by zooplankton. Those microscopic creatures then excrete pellets that sink to the bottom of the ocean and decay, a process that depletes the water of oxygen.
Researchers set out last July to study the dead zone, taking water samples and measuring the total affected area. Some water samples showed no oxygen at all, and smelled of hydrogen sulfide, a rotten egg smell that indicates organic sediments on the sea floor.
The dead zone has grown steadily over the past few decades. Though it tends to disappear in October once cold weather sets in, there’s a “legacy” left behind due to the fact that not all organic matter on the bottom decays in any given year. This means that even if the same amount of nitrogen is released into the Gulf year after year, the dead zone will get larger.
A recent study identified many of the sources of the nitrogen runoff along the Mississippi River, and the government plans to help states focus their pollution-reduction efforts to prevent some of the runoff from ending up in the river.
Great Pacific Garbage Patch
Image credit: Wikipedia
The Great Pacific Garbage Patch, also known as the Pacific Ocean Trash Gyre, Eastern Garbage Patch or Pacific Trash Vortex, is a huge swirling mess of plastic in the North Central Pacific Ocean estimated by some to be the size of the United States. In fact, it’s even been referred to as the world’s largest garbage dump. The Algalita Marine Research Foundationfound in 2008 that plastic outnumbers plankton in some areas of the patch by 48 to 1. Algalita’s education advisor Anna Cummins described the pollution just under the surface of the water as ‘plastic soup’.
It formed gradually over time as a result of marine pollution, gathered together in one area by oceanic currents, and may contain over 100 million tons of debris. Charles Moore, a California-based sea captain and ocean researcher who came upon the patch after competing in a sailing race, estimates that 80% of the garbage comes from land-based sources, with the other 20% coming from ships.
Much of the plastic in this patch and elsewhere in the ocean end up in the digestive systems of sea creatures including turtles, jellyfish, marine birds and other sea life.
The company responsible for an oil well that spewed its contents into the Timor Sea for more than two months says it knows what caused the environmental disaster.
But PTTEP Australasia chief financial officer Jose Martins has refused to reveal what the reasons for the Montara oil well spill and West Atlas rig fire are.
The well began spilling oil on August 21, while the fire broke out on the rig on Sunday. The clean-up effort was hampered by the time it took to get a second rig in place to drill a relief well, while it also took several attempts to finally stop the leak yesterday.
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"Yes we do (know the causes), there's a range of causes but we're not going to go into it," Mr Martins told ABC Radio.
"There's going to be a proper legal process that would be undertaken to find out what caused the leak.
He also revealed he expected an insurance claim to recover costs of the incident to be "much higher" than the $170 million it had cost the company so far, to take into account costs of the rig fire.
The clean-up has cost the company about $5 million so far, but this could also rise, Mr Martins said.
PTTEP would not request any federal government help.
The clean-up was expected to take another two months, but it could take up to seven years to work through the environmental effects of the disaster, Mr Martins said.
Read more: http://www.watoday.com.au/environment/we-know-what-caused-oil-spill-20091104-hws6.html#ixzz1MqKFN6Ax
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