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The oxygen minimum zone (OMZ), sometimes referred to as the shadow zone, is the zone in which oxygen saturation in seawater in the ocean is at its lowest. This zone occurs at depths of about 200 to 1,500 m (700–4,900 ft), depending on local circumstances.
The amount of N 2 fixation and the distribution of diazotrophs in the ocean is determined by the availability of oxygen (O 2), light, phosphorus (P), iron (Fe), and organic matter, as well as habitat temperature. N 2 fixation has been found in some anoxic systems, generally associated with sulfate reducers or oxidizers. [8]
Oxygen depletion is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity. A system with low concentration—in the range between 1 and 30% saturation—is called hypoxic or dysoxic .
Measurement of dissolved oxygen in coastal and open ocean waters for the past 50 years has revealed a marked decline in oxygen content. [24] [16] [25] This decline is associated with expanding spatial extent, expanding vertical extent, and prolonged duration of oxygen-poor conditions in all regions of the global oceans. Examinations of the ...
The limiting oxygen concentration (LOC), [1] also known as the minimum oxygen concentration (MOC), [2] is defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. It is expressed in units of volume percent of oxygen. The LOC varies with pressure and temperature.
The oxygen consumption due to respiration of most of the sinking organic matter and lack of gas exchange, often creates an oxygen minimum zone (OMZ) in the mesopelagic. The mesopelagic OMZ is particularly severe in the eastern tropical Pacific Ocean and tropical Indian Ocean due to poor ventilation and high rates of organic carbon export to the ...
[1] [2] The need for this technology for food arises from the short shelf life of food products such as meat, fish, poultry, and dairy in the presence of oxygen. In food, oxygen is readily available for lipid oxidation reactions. Oxygen also helps maintain high respiration rates of fresh produce, which contribute to shortened shelf life. [3]
Ways to control oxygen intake include gas-generating packs and gas exchange. [4] As oxystat bioreactors are expensive to buy and run, lower-cost solutions have been devised. For example, the Micro-Oxygenated Culture Device (MOCD) is a system involving ordinary flasks, oxygen-permeable tubes, sensors, and water pumps.