Anammox is a new pathway in the nitrogen cycle, in which NH4+ oxidiation is coupled
to NO2- reduction to produce N2. Anammox was first discovered in a wastewater treatment plant
in 1995, and the process was attributed to bacteria that branch deeply in the bacterial genus
Planctomycetes. Since this initial finding, anammox bacteria have been detected in anoxic
marine sediments, oxygen minimum zones of the oceanic water column, estuaries, arctic sea ice,
and even a freshwater lake. Activity measurements have further revealed that these bacteria can
contribute significantly to the nitrogen removal process. This chemolithotrophic process is a new
loop in the biogeochemical nitrogen cycle that was previously unknown. Prior to the discovery
of anammox, denitrification was considered to be the only process responsible for nitrogen
removal via N2 gas production. Little is known about the genetics, ecology, and physiology of
this organism. Therefore, this study was an attempt to gain better understanding in the
community structure of anammox bacteria and their activity related to environmental parameters
such as, ammonium, nitrate, and salinity levels. The Cape Fear River Estuary was chosen as the
study site. A combination of molecular tools and stable isotope probing technique was employed
to study anammox bacteria in the Cape Fear River Estuary. Anammox bacteria were identified
at all three sampling sites, and each site had distinct community structure. Salinity and
ammonium levels were positively correlated with diversity. Although, no correlation could be
established between environmental parameters and activity levels, there did seem to be a link
between community structure and activity levels