Search results
Results from the WOW.Com Content Network
You are free: to share – to copy, distribute and transmit the work; to remix – to adapt the work; Under the following conditions: attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses ...
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. [1] Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes.
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. [19]
The Atlantic Ocean is teeming with life, but for the first time researchers have discovered dead zones in these waters - areas low in both oxygen and salinity - off the coast of Africa. Fish can't ...
Open ocean areas with no oxygen have grown more than 1.7 million square miles in the last 50 years, and coastal waters have seen a tenfold increase in low-oxygen areas in the same time. [34] Measurement of dissolved oxygen in coastal and open ocean waters for the past 50 years has revealed a marked decline in oxygen content.
In OMZs oxygen concentration drops to levels <10 nM at the base of the oxycline and can remain anoxic for over 700 m depth. [7] This lack of oxygen can be reinforced or increased due to physical processes changing oxygen supply such as eddy-driven advection, [7] sluggish ventilation, [8] increases in ocean stratification, and increases in ocean temperature which reduces oxygen solubility.
If oxygen depletion progresses to hypoxia, fish kills can occur and invertebrates like worms and clams on the bottom may be killed as well. 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. Hypoxia may also occur in the absence of pollutants.
The mesopelagic zone is important for water mass formation, such as mode water. Mode water is a water mass that is typically defined by its vertically mixed properties. [5] It often forms as deep mixed layers at the depth of the thermocline. [5] The mode water in the mesopelagic has residency times on decadal or century scales. [5]