Forest disturbance increases soil nitrification rates in temperate ecosystems, but little is understood regarding contributions of newly discovered complete ammonia-oxidizing bacteria (i.e., comammox) to this important ecosystem process. We sampled soils across eight historically disturbed and adjacent reference forested watersheds at the Coweeta Hydrologic Laboratory in North Carolina and used qPCR to determine abundance of three groups of nitrifiers: canonical ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and comammox bacteria (CAOB). All three groups exhibited significantly higher abundance in disturbed soils, though CAOB were more abundant than either AOA or AOB. Further, CAOB showed similar correlations with soil variables compared with AOB, suggesting similar niche requirements. CAOB were better predictors of soil NO₃⁻ relative to AOA and AOB, suggesting CAOB are functionally relevant to nitrification in temperate forests.

森林干扰增加了温带生态系统中的土壤硝化速率，但对于新发现的完全氨氧化细菌（即，comammox）对这一重要的生态系统过程的贡献知之甚少。我们在北卡罗来纳州的Coweeta水文学实验室对八个历史受干扰和相邻的参考森林流域进行了土壤采样，并使用qPCR确定了三组硝化器的丰度：典型的氨氧化细菌（AOB），氨氧化古细菌（AOA）和comammox细菌（CAOB）。尽管CAOB比AOA或AOB都丰富，但是这三组在受干扰的土壤中均显示出更高的丰度。此外，与AOB相比，CAOB与土壤变量具有相似的相关性，表明类似的利基需求。CAOB是土壤NO的更好预测因子₃ ^-相对于AOA和AOB，提示CAOB是在温带森林硝化功能相关。