Oxic respiration

Reaction Potentials. The reaction potentials Vm. Vq and Vr are the rates at which methanogenesis, CH4 oxidation and oxic respiration would proceed in situ were all enzymes saturated with the necessary substrates. They depend on in situ enzyme concentrations and hence on in situ microbial populations. They change over time. 

Canfield, D. E. (2006). Models of oxic respiration, denitrification and sulfate reduction in zones of coastal upweUing. Geochimica et Cosmochimica Acta, doi 10.1016/j.gca.2006.1007.1023. 

Canheld D. E. (1989) Sulfate reduction and oxic respiration in marine sediments implications for organic carbon preservation in euxinic environments. Deep-Sea Res. 36(1), 121-138. 

Muller and Suess (1979) demonstrated the influence of sedimentation rate on organic carbon accumulation under oxic open-ocean conditions. They found that the organic carbon content of marine sediments increases by a factor of about two for every tenfold increase in sedimentation rate. The underlying mechanism was believed to be the more rapid removal and protection of organic matter from oxic respiration and benthic digestion at the sediment/water interface by increasingly rapid burial (cf Sect. 12.3.3). Also... 

The general equations of coupled oxic respiration and nitrification (6.1) and denitrification... 

We already emphasized the importance of oxic respiration over other pathways in the deep-sea. Denitrification (or related processes) only account for a few percent of the carbon oxidation rate by... 

Fig. 6.19 Ratio of carbon oxidation by denitrification and oxic respiration as a function of bottom water oxygen content (after Canfield 1993).

Fig. 6.20 Diffusive oxygen fluxes (a) and oxygen penetration depths (b) for a number of sites in the South Atlantic and the Canaries (from Wenzhofer and Glud 2002). Oxic respiration decreases with increasing water depth resulting in higher oxygen penetration into the sediment.

Four flux categories are given in Table 9.7 The COj produced due to oxic respiration, calcite dissolution, the alkalinity as a sum parameter for calcium carbonate dissolution and CO from oxic respiration, and, hitherto neglected in the discussion, the dissolved organic carbon (DOC). 

Estimated as oxic respiration of organic matter. 2 Using data of Broecker and Peng (1 987). 

Adler, M., Hensen, C., Wenzhofer, F., Pfeifer, K. and Schulz, H.D., 2001. Modeling of calcite dissolution hy oxic respiration in supralysoclinal deep-sea sediments. Marine Geology, 177 167-189. 

Degradation of OM is the main biogeochemical process taking place in recently deposited sediments (Berner, 1980). Depth distributions of microbially mediated electron transfer reactions within sediments are determined by their corresponding redox potentials (Stumm and Morgan, 1996). A distinction between an oxic layer (oxic respiration), a suboxic layer (denitrification, Mn(III,IV) and Fe(III) reduction) and an anoxic layer (sulphate reduction and methanogenesis) is usually made (Froelich et al, 1979). 

Comparable to oxic respiration, denitrification is limited to the top layer of the sediment. As shown in Fig. 1, nitrate is completely reduced within 1 cm below the... 

Respiration, in which organic compounds undergo catabolism that requires molecular oxygen (aerobic or oxic respiration) or that occurs in the absence of molecular oxygen (anaerobic or anoxic respiration). Aerobic respiration uses the Krebs cycle to obtain energy from the reaction... 

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