Nitrogen Cycling in Coral Reef Environments

Sea surface warming, coral disease and nitrogen dynamics 

Elevated Nutrients on Coral Reefs Experiment (ENCORE) 

Studying the changes in nutrient concentrations in waters before and after they flow over reefs was an approach first utiHzed to study coral reef nitrogen dynamics 

The fact that symbiotic associations on reefs are more complex than we have realized to date, is further demonstrated by work in the Caribbean using 5 values, 

Since nitrogen concentrations in pore water are higher than in the water column, there is often a net flux of nutrients out of the sediments (Wilhams et al., 1985). This may be of particular importance in areas of low flushing and poohng in reef areas (Szmant-Froehch, 1983 Szmant, 2002). However, these processes are also quite variable in space and time due to various factors including sediment type, hydrodynamics and loading (Corredor and Morrell, 1985). 

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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.

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