Abstract:The biogeochemical cycling of nitrogen is a significant factor influencing global climatic change. It is a complex process involving interactions between the atmosphere, seawater, sediments, and microorganisms. Nitrogen cycling is particularly active in estuarine and coastal zones, regions where human activities can impact on the natural process. There are four major processes in biogeochemical cycling: nitrification fixation;organic nitrogen ammonification;nitrification, and denitrification. The mechanism...