Global warming could affect marine life and boost areas of ocean water with little oxygen. These regions are with little oxygen are called oxygen minimum zones (OMZs). Researchers predict that the amount of hypoxic water could increase by 50% by 2100. Dead zones are either caused by global warming or eutrophication, the overenrichment of the sea by nutrients. Subduction or upwelling could also cause dead zones.
Problems with the ocean's water mixing system begins as temperatures warm. With higher temperatures, the surface ocean acts like a cap that prevents oxygen from getting into deeper layers. As temperatures increase, that cap gets stronger and stronger and therefore oxygen can't penetrate into the water. The most common cause for dead zones is eutrophication. When nitrogen or phosphorus is leaked into the ocean, it enables phytoplankton to grow. However, the large mass of phytoplankton blocks the sunlight essential to plants living on the floor. As a result, the plants die, creating a large amount of decaying organic material. Bacteria depletes oxygen to break down the organic matter, creating dead zones. It can also happen through subduction, which is when cold surface waters become dense enough to sink into low oxygenated waters, or through a process called upwelling, when oxygen poor waters rise up into surface waters.
Dead zones are a serious problem and I chose this article because it affects marine life, which affects humans. Fishermen are saying that their catches are lower and they are pulling up more dead fish. There is also evidence that fish are moving closer to the water surface, probably because of expanded oxygen minimum zones. What we can do is prevent global warming by decreasing the release of fossil fuels and stop agricultural runoff and the use of fertilize to decrease the release of phosphorus and nitrogen.
Source:http://www.scientificamerican.com/article/global-warming-may-boost-dead-zones-in-oceans/
Article by Niina Heikknen on February 10,2015
Problems with the ocean's water mixing system begins as temperatures warm. With higher temperatures, the surface ocean acts like a cap that prevents oxygen from getting into deeper layers. As temperatures increase, that cap gets stronger and stronger and therefore oxygen can't penetrate into the water. The most common cause for dead zones is eutrophication. When nitrogen or phosphorus is leaked into the ocean, it enables phytoplankton to grow. However, the large mass of phytoplankton blocks the sunlight essential to plants living on the floor. As a result, the plants die, creating a large amount of decaying organic material. Bacteria depletes oxygen to break down the organic matter, creating dead zones. It can also happen through subduction, which is when cold surface waters become dense enough to sink into low oxygenated waters, or through a process called upwelling, when oxygen poor waters rise up into surface waters.
Dead zones are a serious problem and I chose this article because it affects marine life, which affects humans. Fishermen are saying that their catches are lower and they are pulling up more dead fish. There is also evidence that fish are moving closer to the water surface, probably because of expanded oxygen minimum zones. What we can do is prevent global warming by decreasing the release of fossil fuels and stop agricultural runoff and the use of fertilize to decrease the release of phosphorus and nitrogen.
Source:http://www.scientificamerican.com/article/global-warming-may-boost-dead-zones-in-oceans/
Article by Niina Heikknen on February 10,2015