Methods in Biogeochemistry

A diversity of approaches, of which only a few examples can be discussed here, is used in marine biogeochemistry (Fig. 5.2). Among the important goals is to quantify the rate at which biological and chemical processes take place in different depth zones of the sediment. These are often fast processes for which the reactants may have turnover times in the order of days or hours or even minutes. Data on dissolved species in the pore water and on solid-phase geochemistry can be used in diagenetic models to calculate such rates, as discussed in Chapter 3 (e.g. Schulz et al. 1994). The dynamic process is then derived from the 

Another problem is that many compounds are not only consumed but also recycled in a chemical zone. Thus, sulfate in the upper sediment layers is both consumed by sulfate reduction and produced by sulfide oxidation so that the net sulfate removal may be insignificant relative to the total reduction rate. The net removal of sulfate in the whole sediment column is determined by the amount of sulfide trapped in pyrite and is often only 10% of the gross sulfate reduction. 

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Nuster, J., 2005. New methods in biogeochemistry The development of electrochemical tools for the measurement of dissolved and solid state compounds in natural systems. PhD Thesis, University of Bremen, 216 pp. 

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