Responses of aerobic and anaerobic ammonia/ammonium-oxidizing microorganisms to anthropogenic pollution in coastal marine environments

Up to date, numerous studies have shown that the community structure of aerobic ammonia oxidizers including ammonia-oxidizing Betaproteobacteria (Beta-AOB) and ammonia-oxidizing archaea (AOA) and, more recently, the anaerobic ammonium-oxidizing (anammox) bacteria is responsive to environmental conditions including salinity, pH, selected metal ions, concentrations of inorganic nitrogen, total phosphorus, the ratio of organic carbon and nitrogen, and sedimentological factors such as the sediment median grain size. Identification of these responses to known anthropogenic pollution is of particular interest to better understand the growth dynamics and activities of nitrogen transforming microorganisms in marine environments. This chapter discusses currently available methods including molecular ecological analysis using clone library constructions with specific molecular genetic markers for delineating community changes of Beta-AOB, AOA, and anammox bacteria. Using data on ammonia-oxidizing microbial community structures from Jiaozhou Bay in North China and three marine environments with anthropogenic pollution gradients in South China from coastal Mai Po Nature Reserve of Hong Kong to the South China Sea as examples, statistical analyses packages (DOTUR, UniFrac, and Canoco) are presented as useful tools to illustrate the relationship between changes in nitrogen metabolizing microbial communities and established environmental variables.