Phytoplankton ocean water

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. 

Measurements by Thompson et al. (1978) on cultured populations of phytoplankton, such as might be expected to scatter light in ocean waters, revealed only a scattering matrix of the form (13.5), characteristic of particles for which either the Rayleigh (Chapter 5) or Rayleigh-Gans (Chapter 6) approximations are valid. 

Goldman, J. C., J. J. McCarthy, and D. G. Peavey. 1979. Growth rate influence on the chemical composition of phytoplankton in oceanic waters. Nature 279 210-215. 

Although there have only been a few studies to date, it has been suggested that coastal plumes (Turner et al., 1996 Simo et al., 1997) and estuaries (Iverson et al., 1989 Cerqueira and Pio, 1999) may be important atmospheric sources of DMS. DMS, a compound produced by certain phytoplankton, has been shown to have possible implications for climate control once released into the atmosphere (Charlson et al., 1987). DMS is formed by cleavage of dimethylsulfoniopropionate (DMSP) (Kiene, 1990). In fact, DMSP, shown to be correlated with bacterial activity, may provide as much as 100% of the sulfur and 3.4% of the carbon required for bacterial growth in oceanic waters (Kiene and Linn, 2000). Other sulfur compounds such as COS and carbon disulfide (CS2) have also been shown to be possible sources of S in estuaries. For example, significant concentrations of COS and CS2 were found in four European estuaries, 220 150 and 25 6 pM (Sciare et al., 2002). COS is the most abundant sulfur compound in the... 

Fitzwater SE, Johnson KS, Gordon RM, Coale KH, Smith WO (2000) Trace metal concentrations in the Ross Sea and their relationship with nutrients and growth. Deep-Sea Res Part II 47 3159-3179 Gerringa LJA, de Baar HJW, Timmermans KR (2000) A comparison of iron limitation of phytoplankton in natural oceanic waters and laboratory media conditioned with EDTA. Mar Chem 68 335-346 Gibson JAE, Garrick RC, Burton HR, McTaggart AR (1990) Dimethylsulfide and the alga Phaeocystis pouchetii in Antarctic coastal waters. Mar Biol 104 339-346... 

Gerringa LJA, de Baar HJW, Timmermans KR (2000) A comparison of iron limitation of phytoplankton in natural oceanic waters and laboratory media conditioned with EDTA. Mar Chem 68 335-346... 

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