The interactive effects of excess reactive nitrogen and climate change on aquatic ecosystems and water resources of the United States
The interactive effects of excess reactive nitrogen and climate change on aquatic ecosystems and water resources of the United States
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DOI：
10.1007/s10533-012-9788-y
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发表时间：
2013-07-01
期刊：
影响因子：
4
通讯作者：
Boyer, E. W.
中科院分区：
文献类型：
--
作者：
Baron, J. S.;Hall, E. K.;Boyer, E. W.
美国几乎所有的淡水和沿海地区都因过量活性氮（Nr）的输入而退化，其来源是径流，大气氮沉积以及进口食品和饲料。一些主要的不利影响包括有害藻华、淡水和沿海沃茨缺氧、海洋酸化、对人类健康的长期危害以及温室气体排放量增加。氮通量的沿海地区和排放的一氧化二氮从沃茨增加响应N输入。反硝化作用和有机氮在沉积物中的沉积是氮向下游转移的重要过程。水生生态系统是特别重要的反硝化热点。Nr增加了沉积物中的碳储存，但碳是否被永久埋藏尚不清楚。气候变化对淡水和沿海沃茨中氮素运输和加工的影响将通过水文循环的变化而最强烈地感受到，而氮素负荷大多与气候无关。降水量和动态的变化将改变径流，从而影响氮输入到水生生态系统和地下水和水的停留时间，影响氮去除水生系统内的速率。基础设施和气候变化都改变了景观连通性和水文停留时间，这对脱氮至关重要。虽然氮输入和去除率从水生系统的影响，气候和管理，减少氮输入从其来源将是最有效的手段，以防止或尽量减少环境和经济影响的过剩氮对国家的水资源。
Nearly all freshwaters and coastal zones of the US are degraded from inputs of excess reactive nitrogen (Nr), sources of which are runoff, atmospheric N deposition, and imported food and feed. Some major adverse effects include harmful algal blooms, hypoxia of fresh and coastal waters, ocean acidification, long-term harm to human health, and increased emissions of greenhouse gases. Nitrogen fluxes to coastal areas and emissions of nitrous oxide from waters have increased in response to N inputs. Denitrification and sedimentation of organic N to sediments are important processes that divert N from downstream transport. Aquatic ecosystems are particularly important denitrification hotspots. Carbon storage in sediments is enhanced by Nr, but whether carbon is permanently buried is unknown. The effect of climate change on N transport and processing in fresh and coastal waters will be felt most strongly through changes to the hydrologic cycle, whereas N loading is mostly climate-independent. Alterations in precipitation amount and dynamics will alter runoff, thereby influencing both rates of Nr inputs to aquatic ecosystems and groundwater and the water residence times that affect Nr removal within aquatic systems. Both infrastructure and climate change alter the landscape connectivity and hydrologic residence time that are essential to denitrification. While Nr inputs to and removal rates from aquatic systems are influenced by climate and management, reduction of N inputs from their source will be the most effective means to prevent or to minimize environmental and economic impacts of excess Nr to the nation's water resources.