Nitrogen estuarine denitrification

Figure 16.2 Model-predicted latitudinal distribution in the North Atlantic Basin (a) estuarine denitrification (b) total nitrogen transport by rivers. (Modified from Seitzinger, 2000.)...

Nowicki, B.L. (1994) The effect of temperature, oxygen, salinity, and nutrient enrichment on estuarine denitrification rates measured with a modified nitrogen gas flux technique. Estuar. Coastal Shelf Sci. 38, 137-156. 

Nielsen, K., Nielsen, L.P., and Rasmussen, P. (1995) Estuarine nitrogen retention independently estimated by the denitrification rate and mass balance methods a study of Norsminde Fjord, Denmark. Mar. Ecol. Prog. Ser. 119, 275-283. 

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... 

Azni, S., Abd. Aziz, S. Nedwell, D.B. (1986) The nitrogen cycle of an East Coast, U.K. saltmarsh IL Nitrogen fixation, nitrification, denitrification, tidal exchange. Estuarine, Coastal and Shelf Science 22, 689-704. 

The sediments are also important sites for ther removal of fixed nitrogen from coastal waters. Because there is relatively little NOs in the shallow waters overlying coastal and estuarine sediments, diffusion of NOs from bottom water is not a major source of N for denitrification. However, rapid organic matter oxidation results in the release of NH4+ to the pore waters. NH4+ can be converted to Ni by a nitrification/denitrification cycle or by NH4+ oxidation coupled to the reduction of NOs ... 

---