Balancing macronutrient stoichiometry to alleviate eutrophication.
Balancing macronutrient stoichiometry to alleviate eutrophication.
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DOI：
10.1016/j.scitotenv.2018.03.298
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
M. Stutter;D. Graeber;C. Evans;A. Wade;P. Withers
中科院分区：
文献类型：
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作者：
M. Stutter;D. Graeber;C. Evans;A. Wade;P. Withers
活性氮（N）和磷（P）输入到地表沃茨中会改变水环境，影响公众健康和娱乐。源控制主导富营养化管理，而营养物质的生物调节在很大程度上被忽视，虽然水生微生物具有巨大的潜力，处理营养物质。化学计量比的有机碳（OC），氮，磷原子应调节异养途径的水生营养加工，高OC的可用性有利于水生微生物处理。异养微生物处理通过反硝化作用去除N，并以有机络合的、较少富营养化的形式捕获N和P。与全球数据合成，我们表明，在河流与城市和农业用地的生物可利用的溶解有机碳的原子比，无论是N或P往往是远离“微生物最佳”。这种有机碳缺乏相对于高可用性的N和P可能会导致河流内异养处理。我们建议，溪流和河流保留N和P的能力可以通过积极的化学计量再平衡来提高。虽然自养有机碳生产有助于异养率实质性控制营养加工从外来有机碳记录为N和一个新兴领域的P。因此，重新平衡应重新连接适当的有机碳来源，如湿地和河岸森林，已成为断开连接的河流，同时与农业和城市化。然而，关键的知识差距需要研究之前，这种方法在管理中的安全实施：（一）评估系统响应流域输入的溶解态有机碳的形式和数量相对于内部生产的自养溶解态有机碳和水生和陆生颗粒态有机碳和（ii）评估风险因素缺氧介导的磷解吸与OC升高的情况。尽管如此，我们发现化学计量再平衡，通过重新连接景观有益的有机碳源有相当大的潜力，河流管理，以减轻富营养化，改善水质和水生生态系统的健康，如果加强营养源控制。
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.