Caffrey Jane M, Bano Nasreen, Kalanetra Karen, Hollibaugh James T
Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, FL, USA.
ISME J. 2007 Nov;1(7):660-2. doi: 10.1038/ismej.2007.79. Epub 2007 Oct 4.
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.
硝化作用，即将NH₄⁺氧化为NO₂⁻并随后氧化为NO₃⁻，在氮循环中起着核心作用，并且通常是从河口和沿海环境中去除氮的关键第一步。硝化作用的第一步也是限速步骤由氨单加氧酶（AmoA）催化。我们评估了氨氧化古菌（AOA）和氨氧化细菌（AOB）amoA基因丰度之间的关系；潜在硝化速率和环境变量，以确定影响河口沉积物中AOA丰度和硝化菌活性的因素。我们的结果表明，潜在硝化速率随着AOA amoA丰度的增加而增加。相比之下，潜在硝化速率与AOB amoA丰度之间没有关系。这表明AOA在河口氮循环中具有重要意义。令人惊讶的是，潜在硝化速率的更多变异性是由盐度和孔隙水硫化物预测的，而不是由溶解氧历史预测的。
