Ammonia oxidation and ammonia-oxidizing bacteria and archaea from estuaries with differing histories of hypoxia.
Nitrification, the oxidation of NH(4)(+) to NO(2)(-) and subsequently to NO(3)(-), plays a central role in the nitrogen cycle and is often a critical first step in nitrogen removal from estuarine and coastal environments. The first and rate-limiting step in nitrification is catalyzed by the enzyme ammonia monooxygenase (AmoA). We evaluate the relationships between the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) amoA genes; potential nitrification rates and environmental variables to identify factors influencing AOA abundance and nitrifier activity in estuarine sediments. Our results showed that potential nitrification rates increased as abundance of AOA amoA increased. In contrast, there was no relationship between potential nitrification rates and AOB amoA abundance. This suggests that AOA are significant in estuarine nitrogen cycling. Surprisingly, more of the variability in potential nitrification rates was predicted by salinity and pore water sulfide than by dissolved oxygen history.
Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, FL, USA. jcaffrey@uwf.edu
Jane M
JM
Caffrey
Nasreen
N
Bano
Karen
K
Kalanetra
James T
JT
Hollibaugh
D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D013440:Sulfides / Q000378:metabolism; D014871:Water Microbiology
D012336:RNA, Ribosomal, 16S; D013440:Sulfides; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase; D009584:Nitrogen; D010100:Oxygen