Organic carbon particulate

The quantity of primary production that is exported from the upper ocean is said to be equivalent to new production (18, 19) New primary production is that associated with allocthonous nutrients (i.e., those upwelled or mixed into the euphotic zone or input via rivers and rain). In order for steady state to be maintained, an equivalent flux out of the euphotic zone is required. Earlier studies (19) suggested that sediment-trap measurements of particulate organic carbon (POC) flux were equivalent to new primary production however, recently it has become clear that these measurements probably represent only a... 

Fig. 10-15 Organic carbon fluxes with depth in the water column normalized to mean annual primary production rates at the sites of sediment trap deployment. The undulating line indicates the base of the euphotic zone the horizontal error bars reflect variations in mean annual productivity as well as replicate flux measurements during the same season or over several seasons vertical error bars are depth ranges of several sediment trap deployments and uncertainities in the exact depth location. (Reproduced with permission from E. Suess (1980). Particulate organic carbon flux in the oceans - surface productivity and oxygen utilization, Nature 288 260-263, Macmillan Magazines.)...

The distribution of dissolved, total particulate, and living particulate organic carbon in the surface (0-300 m) and deep ocean (>300 m) are summarized in Table 10-6. Recent analytical advances have greatly improved our understanding of the distributions of DOC in the ocean (Hedges and Lee, 1993). The important aspects of this compilation are ... 

Murray, J. W., Young, J., Newton, J. et al. (1996). Export flux of particulate organic carbon from the central equatorial Pacific determined using a combined drifting trap- Th approach. Deep-Sea Res. II 45,1095-1132. 

Suess, E. (1980). Particulate organic carbon flux in the oceans-surface productivity and oxygen utilization. Nature 288, 260-263. 

Buesseler KO, Ball L, Andrews J, Benitez-Nelson C, Belastock R, Chai F, Chao Y (1998) Upper ocean export of particulate organic carbon in the Arabian Sea derived from thorium-234. Deep-Sea Res II 45 2461-2487... 

Cochran JK, Barnes C, Achman D, Hirschberg DJ (1995) Thorium-234/Uranium-238 disequilibrium as an indicator of scavenging rates and particulate organic carbon fluxes in the Northeast Water Polynya, Greenland. J Geophys Res 100(C3) 4399-4410... 

Hall IR, Schmidt S, McCave IN, Reyss J-L (2000) Suspended sediment distribution and Th-234/U-238 disequilibrium along the Northern Iberian Margin implication for particulate organic carbon export. Deep-Sea Res 147 557-582... 

The carbon dioxide resulting from combustion of the particulate organic carbon can be passed through the analyser, producing a single spike on a recorder, or it can be pumped in a loop through the analyser, until an equilibrium concentration is reached in the loop. Since the output of the analyser is nonlinear, the latter technique has been favoured by some investigators [46]. 

An alternative method for the determination of particulate organic carbon in marine sediments is based on oxidation with potassium persulfate followed by measurement of carbon dioxide by a Carlo Erba non-dispersive infrared analyser [152,153]. This procedure has been applied to estuarine and high-carbonate oceanic sediments, and results compared with those obtained by a high-temperature combustion method. 

Ehrhardt M (1976) Determination of particulate organic carbon and nitrogen. In Grasshoff K (ed) Methods of seawater analysis. Verlag Chemie, New York, pp 215-220... 

Infrared spectroscopy has been applied to the determination of particulate organic carbon in non-saline sediments, aliphatic hydrocarbons and total organic carbon in saline sediments and mixtures of organics in sludges. 

Combustion methods have been used to determine total sulphur and total organic carbon and total halides in soil, total and particulate organic carbon, total halide, phosphorus and nitrogen, total and particulate organic carbon in saline sediments and total nitrogen in sludges. 

For practical purposes, the distinction between dissolved organic carbon and particulate organic carbon is that the latter is retained on filters of known porosity. Membrane filters with 0.25-1. Oum pore size and glass fibre Whatman G F/C filters are commonly used. By using the particulate fraction of a sample retained on pre-combusted Whatman G F/C filters for... 

Krambeck et al. [40] measured small quantities of particulate carbon in lake waters by an automated furnace combustion infrared procedure. The whole sequence of operations was controlled with the aid of an AIM65 desktop computer. The system was successfully operated for routine analysis of samples of lake water with particulate organic carbon values of 100-300ug L 1 carbon a single analysis takes 8min. The relative standard deviation was about 1%. 

Hulsmann and Hengst [41] used wet oxidation by potassium persulphate in sealed ampoules to estimate particulate organic carbon. Inorganic carbon was first removed from the sample prior to reaction with persulphate. 

Dankers and Laane [43] compared two methods, based on wet oxidation with potassium peroxydisulphate and loss on ignition at 560°C, for the determination of particulate organic carbon in estuarine suspended matter. They found that in estuarine sediments with a high clay content, loss on... 

PAH PCB POC POM Polynuclear Aromatic Hydrocarbons Polychlorinated biphenyl Particulate Organic Carbon Particulate Organic Matter... 

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