Ocean water, phytoplankton organisms

In addition to the dissolved elements and compounds in the oceanic water column, a wide variety of water column chemicals are found in marine organisms and organic detritus. For example, a milliliter of surface seawater can contain on the order of 10 million viruses, 1 million bacteria, 100,000 phytoplankton, and 10,000 zooplankton [9]. With the advent of soft ionization processes for mass spectrometry systems, scientists have been able to study these marine organisms at molecular level. The use of electrospray ionization (ESI see Section 2.1.15), atmospheric pressure chemical ionization... 

In addition to adsorption processes, phytoplankton can absorb (assimilate) certain nutrient metal ions (or metal ions that are by the organisms mistaken as nutrients). As with other nutrients, this uptake can occur in stoichiometric proportions. The uptake (and subsequent release upon mineralization) of nutrients in stoichiometric proportions was claimed already 1934 by Redfield. In referring to the atomic proportions C N P Si etc. one refers to the Redfield Ratios. This stoichiometry is well established (at least for the conventional nutrients) in oceanic waters it has also been postulated for lakes (Stumm and Morgan, 1970). 

Sulfur occurs mainly in proteins that typically display a C/S ratio of about 50. The processes responsible for the direct primary production of organically bound sulfur are the direct assimilation of sulfate by living plants and microbiological assimila-tory processes in which organic sulfur compounds are synthesized. Land plants use sulfate available from precipitation, marine phytoplankton use ocean water sulfate. 

Other studies showed that the oligotrophic ocean areas are dominated by phytoplankton organisms of relatively small size, generally less than 5 jLtm. Therefore, the spectral signatures of the oligotrophic small cell size populations should resemble that of the blue water population, and the eutrophic populations typical of coastal and upwelling regions, which gen-... 

L. Prieur, S. Sathyendranath (1981). An optical classification of coastal and oceanic waters based on the specific spectral absorption curves of phytoplankton pigments, dissolved organic matter, and other particulate materials. Limnol. Oceanogr., 26, 671-689. 

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