Search results
Results from the WOW.Com Content Network
The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes.
The marine carbon cycle is a central to the global carbon cycle and contains both inorganic carbon (carbon not associated with a living thing, such as carbon dioxide) and organic carbon (carbon that is, or has been, incorporated into a living thing). Part of the marine carbon cycle transforms carbon between non-living and living matter.
The marine nitrogen cycle consists of complex microbial transformations which include the fixation of nitrogen, its assimilation, nitrification, anammox and denitrification. [78] Some of these processes take place in deep water so that where there is an upwelling of cold waters, and also near estuaries where land-sourced nutrients are present ...
Redfield proposed that the ratio of nitrogen to phosphorus in plankton resulted in the global ocean having a remarkably similar ratio of dissolved nitrate to phosphate (16:1). He considered how the cycles of not just N and P but also C and O could interact to result in this match.
Iron plays an important role in the nitrogen cycle, aside from its role as part of the enzymes involved in nitrogen fixation. In anoxic conditions, Fe(II) can donate an electron that is accepted by NO 3 − which is oxidized to several different forms of nitrogen compounds, NO 2 −, N 2 O, N 2, and NH 4 +, while Fe(II) is reduced to Fe(III). [33]
The diagram on the right shows some human impacts on the marine nitrogen cycle. Bioavailable nitrogen (Nb) is introduced into marine ecosystems by runoff or atmospheric deposition, causing eutrophication , the formation of dead zones and the expansion of the oxygen minimum zones (OMZs).
The biological pump (or ocean carbon biological pump or marine biological carbon pump) is the ocean's biologically driven sequestration of carbon from the atmosphere and land runoff to the ocean interior and seafloor sediments. [1]
Marine chemistry, also known as ocean chemistry or chemical oceanography, is the study of the chemical composition and processes of the world’s oceans, including the interactions between seawater, the atmosphere, the seafloor, and marine organisms. [2]