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  2. Marine biogeochemical cycles - Wikipedia

    en.wikipedia.org/wiki/Marine_biogeochemical_cycles

    The six aforementioned elements are used by organisms in a variety of ways. Hydrogen and oxygen are found in water and organic molecules, both of which are essential to life. Carbon is found in all organic molecules, whereas nitrogen is an important component of nucleic acids and proteins.

  3. Aquatic respiration - Wikipedia

    en.wikipedia.org/wiki/Aquatic_respiration

    In some fish, capillary blood flows in the opposite direction to the water, causing countercurrent exchange. The muscles on the sides of the pharynx push the oxygen-depleted water out the gill openings. In bony fish, the pumping of oxygen-poor water is aided by a bone that surrounds the gills called the operculum. [6]

  4. Biogeochemical cycle - Wikipedia

    en.wikipedia.org/wiki/Biogeochemical_cycle

    Hydrogen and oxygen are found in water and organic molecules, both of which are essential to life. Carbon is found in all organic molecules, whereas nitrogen is an important component of nucleic acids and proteins. Phosphorus is used to make nucleic acids and the phospholipids that comprise biological membranes. Sulfur is critical to the three ...

  5. Carbon-based life - Wikipedia

    en.wikipedia.org/wiki/Carbon-based_life

    Liquid water is essential for carbon-based life. Chemical bonding of carbon molecules requires liquid water. [30] Water has the chemical property to make compound-solvent pairing. [31] Water provides the reversible hydration of carbon dioxide. Hydration of carbon dioxide is needed in carbon-based life. All life on Earth uses the same ...

  6. Marine biogenic calcification - Wikipedia

    en.wikipedia.org/wiki/Marine_biogenic_calcification

    Marine biogenic calcification is the production of calcium carbonate by organisms in the global ocean.. Marine biogenic calcification is the biologically mediated process by which marine organisms produce and deposit calcium carbonate minerals to form skeletal structures or hard tissues.

  7. Gill - Wikipedia

    en.wikipedia.org/wiki/Gill

    The density of the water prevents the gills from collapsing and lying on top of each other; [such collapse] happens when a fish is taken out of water." [ 4 ] Usually water is moved across the gills in one direction by the current, by the motion of the animal through the water, by the beating of cilia or other appendages, or by means of a ...

  8. Microbial loop - Wikipedia

    en.wikipedia.org/wiki/Microbial_loop

    The aquatic microbial loop is a marine trophic pathway which incorporates dissolved organic carbon into the food chain.. The microbial loop describes a trophic pathway where, in aquatic systems, dissolved organic carbon (DOC) is returned to higher trophic levels via its incorporation into bacterial biomass, and then coupled with the classic food chain formed by phytoplankton-zooplankton-nekton.

  9. Biological pump - Wikipedia

    en.wikipedia.org/wiki/Biological_pump

    This biologically fixed carbon is used as a protective coating for many planktonic species (coccolithophores, foraminifera) as well as larger marine organisms (mollusk shells). Calcium carbonate is also excreted at high rates during osmoregulation by fish, and can form in whiting events. [37]