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4) Derived carbohydrate oxydation and reduction products, amino sugars and deoxy sugars. The content of carbohydrate in marine organisms varies between ca. 60 % on a dry weight basis in brown and red algae, ca. 20 % in bacteria, ca. 12 % in phytoplankton, and ca. 2 % in zooplankton and zoobenthos. Mono- and disaccharides and low molecular polysaccharides excreted by living organisms are readily utilized by microorganisms. Carbohydrates such as cellulose and hemicellulose undergo much slower decomposition.

In that case one may express buoyancy as reduced gravity: g(Qdh) instead of the gravity gQl (where g is the gravitational acceleration and Ql and Q2 are densities, Ql of the water considered, Q2 of the surrounding water). For objects with negative buoyancy one usually speaks of the underwater weight. Pelagic organisms are often capable of regulating their buoyancy. Rapid changes in buoyancy can be performed by the ..... gas bladder of fish. Gas-filled spaces are also found in various ..... , in the shells of Nautilus).

Ureum by Wohler in 1828, later more complex compounds by Berthelot), organic synthesis has evolved rapidly in the laboratory as well as in manufacturing. This has led to the introduction of many new organic compounds in the marine environment, including the generally toxic classes of halogenated (chlorinated, brominated) organics. See also ..... carbon cycle. carbon, radioactive due to cosmic radiation from sun activities, a number of natural ..... radionuclides are formed in the atmosphere. Radioactive carbon such as 14C is formed due to neutron capture by nitrogen, whereby stable 14N is transformed into 14C.