ANOXIC+WATER

//** **//One problem caused by pollution that occurs in the midnight zone is called anoxic water. This means that there is no or hardily any dissolved oxygen in the water. When there is no dissolved oxygen, fish and other creatures can’t breathe, and they will quickly die from a lack of oxygen. Some of the creatures that live at this depth might die or migrate to other parts of the ocean. If they do migrate, there is a possibility that there could become a problem in the food chain.//** []
 * //Anoxic Water

** 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 that’s 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 Satellite images can’t see the bottom of the ocean, they can see the surface, where sediments from rivers mix with ocean waters. The images shown here are Satellite images (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. **// []



[]  **__//Q://__** **__//  What is anoxic water? //__** **__// A: Anoxic water is water that doesn't contain the sufficient amount of oxygen, dissolved in it to sustain aquatic life.//__** **__//A://__** **__// Are you a fish? If you aren't, it can't hurt you since you don't live in the water and breathe the oxygen. //__**
 * __//Q://__** **__// Can Anoxic water hurt me? //__**

**__//Q//__** **__//: //__** **__// What dangers does anoxic water hold for us? A: Possible extinction of fish, poisoned sea life, and infected water. There are several more dangers, can you name any? Or find any? //__**  **__//Q://__** **__//Why is anoxic water a threat?//__** **__//A://__** **__//Well, fish cannot live in anoxic environments and the anoxic population keeps growing year after year. If all the world's water becomes anoxic, it will kill the fish. //__**