Effects of Salinity on Acetylene Reduction (Nitrogen Fixation) and Respiration in a Marine Azotobacter

摘要

An acetylene-reducing (nitrogen-fixing) bacterium, identified as Azotobacter sp., was isolated from a site in the Canary Creek Marsh, Del. Acetylene reduction activity of the isolate was maximal at 15 to 25‰ NaCl, with no activity observed at 0 or 60‰. Respiration studies showed similar results, with maximal activity occurring at a slightly lower salinity (10 to 20‰ NaCl). The salinities over which peak activity occurred fell within the normal range of in situ salinity (20 to 28‰ total salinity).