Hypoxia (environmental)
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Hypoxia refers to low oxygen conditions. Hypoxia is problematic for air-breathing organisms, yet it is essential for many anaerobic organisms. Hypoxia applies to many situations, but usually refers to
Still frame from an underwater video of the sea floor. The floor is covered with crabs, fish, and clams apparently dead or dying from oxygen depletion.
Jubilee photo from Mobile Bay
Air pollution 3
Aerial view of Slapton Sands and northern part of Ley geograph.org.uk 1434412
Dead zone (ecology)
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Dead zones are hypoxic areas in the world's oceans and large lakes. Hypoxia occurs when dissolved oxygen concentration falls to or below 2 mg of O2/liter. When a body of water experiences hypoxic cond
Hypoxia (environmental)
…shallow waters of semi-enclosed water bodies such as the Waddenzee or the Gulf of Mexico, where land run-off is substantial. In these areas a so-called "dead zone" can be created. Low dissolved oxygen conditions are often seasonal, as is the case in Hood Canal and areas of Puget Sound, in Washington State. The…
Red circles show the location and size of many dead zones (in 2008). Black dots show dead zones of unknown size. The size and number of marine dead zones—areas where the deep water is so low in dissolved oxygen that sea creatures cannot survive (except for some specialized bacteria)—have grown in the past half-century.
Dead zones are often caused by the decay of algae during algal blooms, like this one off the coast of La Jolla, San Diego, California.
Climate has a significant impact on the growth and decline of ecological dead zones. During spring months, as rainfall increases, more nutrient-rich water flows down the mouth of the Mississippi River. At the same time, as sunlight increases during the spring, algal growth in the dead zones increases dramatically. In fall months, tropical storms begin to enter the Gulf of Mexico and break up the dead zones, and the cycle repeats again in the spring.