Reactive nitrogen (N) and phosphorus (P) inputs to surface waters modify aquatic environments, affect public health and recreation. Source controls dominate eutrophication management, whilst biological regulation of nutrients is largely neglected, although aquatic microbial organisms have huge potential to process nutrients. The stoichiometric ratio of organic carbon (OC) to N to P atoms should modulate heterotrophic pathways of aquatic nutrient processing, as high OC availability favours aquatic microbial processing. Heterotrophic microbial processing removes N by denitrification and captures N and P as organically-complexed, less eutrophying forms. With a global data synthesis, we show that the atomic ratios of bioavailable dissolved OC to either N or P in rivers with urban and agricultural land use are often distant from a “microbial optimum”. This OC-deficiency relative to high availabilities of N and P likely overwhelms within-river heterotrophic processing. We propose that the capability of streams and rivers to retain N and P may be improved by active stoichiometric rebalancing. Although autotrophic OC production contributes to heterotrophic rates substantial control on nutrient processing from allochthonous OC is documented for N and an emerging field for P. Hence, rebalancing should be done by reconnecting appropriate OC sources such as wetlands and riparian forests that have become disconnected from rivers concurrent with agriculture and urbanisation. However, key knowledge gaps require research prior to the safe implementation of this approach in management: (i) to evaluate system responses to catchment inputs of dissolved OC forms and amounts relative to internal production of autotrophic dissolved OC and aquatic and terrestrial particulate OC and (ii) evaluate risk factors in anoxia-mediated P desorption with elevated OC scenarios. Still, we find stoichiometric rebalancing through reconnecting landscape beneficial OC sources has considerable potential for river management to alleviate eutrophication, improve water quality and aquatic ecosystem health, if augmenting nutrient source control.

向地表水中输入的反应性氮（N）和磷（P）会改变水生环境，影响公共健康和娱乐。尽管水生微生物具有巨大的潜力来处理营养物，但源头控制在富营养化管理中占主导地位，而营养物的生物调节却被忽略。有机碳（OC）与N原子和P原子的化学计量比应调节水生养分加工的异养途径，因为高OC利用率有利于水生微生物加工。异养微生物处理通过反硝化作用去除N，并以有机复合，富营养度较低的形式捕获N和P。通过全球数据综合，我们表明在城市和农业用地的河流中，可生物利用的溶解的OC与N或P的原子比通常与“微生物最佳值”相去甚远。相对于N和P的高可用性而言，这种OC缺乏可能会淹没河流内异养过程。我们建议通过积极的化学计量再平衡可以提高河流和河流保留氮和磷的能力。尽管自养OC的产生促进了异养率的形成，但对N和新出现的P的异源OC的养分处理进行了实质性控制。因此，应通过重新连接适当的OC源（如已从河流中断开的湿地和河岸森林）来实现平衡。与农业和城市化同时进行。但是，关键知识缺口需要在安全实施此方法之前进行研究：（i）评估系统对溶存OC形式和相对于自养溶质OC以及水生和陆生颗粒OC内部产生量的集水量输入的响应，以及（ii）评估在OC升高的情况下缺氧介导的P解吸的风险因素。尽管如此，我们发现通过重新连接景观有益的OC源进行化学计量的平衡，如果加强营养源控制，对河流管理具有缓解水体富营养化，改善水质和水生生态系统健康的巨大潜力。