Particulate organic carbon concentrations

Moran, S.B., M.A. Charette, S.M. Pike, and C.A. Wicklund. 1999. Differences in seawater particulate organic carbon concentration samples collected using small-and large-volume methods The importance of DOC adsorption to the filter blank. Mar. Chem. 67 33M2. 

With a particulate organic carbon concentration of Coc = 2 i mol CL", the MTC of the OC settling settling flux, fcep, can be calculated using Equation 17.5 ... 

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]. 

Grosjean, D. Helsler, S. Fung, K. Mueller, P. Hldy, G. "Particulate organic carbon in urban air concentrations, size distribution and temporal variations", presented at the American Institute of Chemical Engineers 72nd Annual Meeting, San Francisco, California, November 1979. 

G.T. Wallace and R.A. Duce, Concentration of particulate trace metals and particulate organic carbon in marine surface waters by a bubble flotation mechanism, Mar. Chem. 3 (1975) 157-181. 

Figure 13.12 Seasonal range of particulate organic carbon (POC) in different regions of San Francisco Bay (1992-1993) and Chesapeake Bay (1995-1996) estuaries. Error bars represent standard deviations for mean concentrations when three sites were measured. (Modified from Canuel, 2001.)...

DOM is composed of small molecules that can be obtained by filtration. Quantification of organic matter in aquatic environment is performed by measuring the concentrations expressed in organic carbon. One measures total organic carbon (TOC) obtained from raw liquid sample, particulate organic carbon (POC) by analyzing the filter, and the dissolved organic carbon (DOC) characterized from the sample after filtration. 

Table 1 Fe concentrations, Chi a per cell, P. antarctica cell abundance, particulate organic carbon (POC), particulate organic nitrogen (PON) and dissolved organic carbon (DOC) in the P. antarctica cultures under low Fe (<1 nM Fe, LFe) and Fe amended (FIFe) conditions used for bacterial regrowth experiments...

Figure 15.7 Fine (< 65 ]im) and coarse (> 65 pm) particulate organic carbon (POC, top), particulate organic nitrogen (PON, middle), and particulate phosphorus (PP, bottom) versus their respective fine or coarse sediment concentration. The symbol key in the lower panel applies to the entire figure.

Carbon is transported into the Amazon River/ocean mixing zone in numerous forms including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). The average DIC, DOC, and POC concentrations in Amazon River water are 460, 275, and 180 pmol L-1 (Richey et al. 1991), which indicates that DOC supply exceeds POC supply and that DIC is the most abundant form of carbon in the river. Sholkovitz et al. (1978) noted that most riverine dissolved... 

Below about 200 m, PON concentrations tend to asymptote to similar levels of about 0.1 to 0.3 pmol kg", irrespective of the large differences in PON in the euphotic zone. Overall, PON dynamics in the aphotic zone tends to follow that of particulate organic carbon (POC), with a stoichiometric C N ratio of about 7.1 0.1 (equivalent to 16 114 2) for the particles sinking out of the euphotic zone (Schneider et al, 2003) (see also Hebei and Karl (2001) for long-term observations of the POC and PON dynamics in an oligotrophic environment). In their analysis of sediment trap samples and particles collected by in situ pumps, Schneider et al (2003) also noticed a slight increase of this ratio with depth of about 0.2 per 1000 m, so that particles sinking across 1000 m have a C N ratio very close to the 117 16 ratio proposed by Anderson and Sarmiento (1994). 

Turekian V. C., Macko S. A., and Keene W. C. (2003) Concentrations, isotopic compositions, and sources of size-resolved, particulate organic carbon and oxalate in nearsurface marine air at Bermuda during spring. J. Geophys. Res. 108, 4157, doi 10.1029/2002JD002053. 

Finally, the importance of dissolved and particulate organic carbon and organic nitrogen compounds is discussed for the Baltic Sea because the effects of eutrophication cannot be properly understood considering only the concentrations of inorganic nutrients. 

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