Distribution, activity, and ecology of anammox bacteria in aquatic environments

Kapitel i bok, 2014

This chapter provides a synthesis of the broadscale patterns of anammox across a spectrum of aquatic ecosystems and to put forward some hypotheses as to what regulates anammox and the total flux of N in such systems. Research into anammox falls largely into two distinct aquatic ecosystems: (i) its role in the anaerobic oxidation of ammonium in the suboxic layers of aquatic sediments, where the respective reactions and ecophysiologies are compressed into fractions of centimeters; and (ii) the same ecosystem function, but distributed over depths of tens of meters in the oxygen minimum zones (OMZs) of the global ocean. The chapter focuses on the results obtained using slurries of homogenized sediment, and then focuses on the data derived with intact sediment cores, and, finally, draw comparisons between the two at the end, without dwelling too long on the respective complexities of each method. Anammox bacteria appear active in both low-oxygen and suboxic waters, and such conditions are often considered as prerequisites for denitrification, since oxygen represses synthesis and activity of denitrifying enzymes, though the effect may be more subtle.