Contrary to the fact that NO₃⁻-N can serve as electron acceptor to promote organics degradation, it was also found NO₃⁻-N reduction does not necessarily promote organics degradation. We speculate nitrogen (N) species may control the interaction between NO₃⁻-N reduction and organics degradation via shifting related microbial community structure. To prove the hypothesis, oxic-anoxic transition zone (OATZ) microcosms simulated by lake water and sediment were conducted with the addition of N species (NO₃⁻-N, NO₂⁻-N, and NH₄⁺-N) and aniline as typical organics. High-throughput sequencing was used to analyze the microbial community structure and functional enzyme in the microcosms. Results show that, NO₂⁻-N inhibited NO₃⁻-N reduction while enhanced aniline degradation. For NH₄⁺-N, it promoted NO₃⁻-N reduction when NH₄⁺-N/NO₃⁻-N concentration ratio ≤ 2 and inhibited aniline degradation when NH₄⁺-N/aniline concentration ratio ≥ 0.5. The presence of NO₂⁻-N or NH₄⁺-N weakened the interaction between NO₃⁻-N reduction and aniline degradation, which might be caused by significant changes in the diversity and abundance of microbial communities controlled by N species. The microbial mechanism indicates that NO₂⁻-N weakened the interaction by affecting both denitrification enzyme activity and electron transfer capability, while NH₄⁺-N weakened the interaction mainly by affecting electron transfer capability. These results imply that N species, as well as other electron acceptors and donors, in the contaminated OATZ should be fully considered, when performing in situ remediation technology of NO₃⁻-N reduction.

与NO ₃ ^-- N可以作为电子受体促进有机物降解的事实相反，还发现NO ₃ ^-- N的还原并不一定促进有机物降解。我们推测氮（N）物种可能通过转移相关的微生物群落结构来控制NO ₃ ^-- N还原与有机物降解之间的相互作用。为了证明这一假设，在湖水和沉积物模拟下，添加了N ₃（_-3 ^-- N，NO ₂ ^-- N和NH ₄ ⁺-N）和苯胺作为典型的有机物。高通量测序用于分析微生物群落中的微生物群落结构和功能酶。结果表明，NO ₂ ^-- N抑制了NO ₃ ^-- N的还原，同时促进了苯胺的降解。对于NH ₄ ⁺ -N，当NH ₄ ⁺ -N / NO ₃ ^-- N浓度比≤2时，可促进NO ₃ ^-- N的还原，而当NH ₄ ⁺ -N /苯胺浓度比≥0.5时可抑制苯胺的降解。NO ₂ ^-- N或NH ₄ ⁺ -N的存在削弱了NO ₃之间的相互作用⁻ -N减少和苯胺降解，这可能是由N种控制的微生物群落的多样性和丰度发生重大变化而引起的。微生物机理表明，NO ₂ ^-- N通过影响反硝化酶活性和电子传递能力来削弱相互作用，而NH ₄ ⁺ -N主要通过影响电子传递能力来削弱相互作用。这些结果表明，在执行NO ₃ ^-- N还原原位修复技术时，应充分考虑受污染的OATZ中的N物种以及其他电子受体和供体。