Coral reefs denitrification

Figure 21.1 Microbial nitrogen cycling processes in sedimentary environments on a coral reef (A) nitrogen fixation (B) ammonification (C) nitrification (D) dissimilatory nitrate reduction and denitrification (E) assimilatory nitrite/nitrate reduction (F) ammonium immobilization and assimilation. Adapted from D Elia and Wiebe (1990). Anammox (the anaerobic oxidation of NH4" with NO2 yielding N2 ) is not represented, as it has not yet been shown to occur on coral reefs, but may be found to be important in reef sediments.

O Neil, J. M., and Capone, D. G. (1996). Effects of elevated nutrients (ENCORE) on benthic nitrogen fixation and denitrification. Proceedings of the 8th International Coral Reef Conference, Panama, June 21—29. 

Marine sediments are an important compartment for N cycHng. Shelf sediments in particular are sites of active denitrification (Codispoti et al., 2001), and estuarine, coastal, and coral reef sediments can be important sites of nitrogen fixation (Burns et al, 2002 Capone, 1983 Capone et al., 1992). Despite extensive study of biogeochemical processes in sediments, the study of the microbial loop in this compartment has had considerably less attention, possibly due to difficulty in studying sediment microorganisms. There are two primary differences between water column and sediment microbial processes. The first of these is the presence... 

Seitzenger, S.P. and D Elia, C.F. (1985) Preliminary studies of denitrification on a coral reef. Symposium for Undersea Resarch, NOAA s Undersea Research Program, 3, 199-208. 

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