Disrupted carbon cycling in restored and unrestored urban streams: Critical timescales and controls
Disrupted carbon cycling in restored and unrestored urban streams: Critical timescales and controls
复制标题
恢复和未恢复的城市河流中碳循环中断：关键时间尺度和控制
DOI：
10.1002/lno.10613
复制
发表时间：
2017
影响因子：
4.5
通讯作者：
J. Harvey
中科院分区：
文献类型：
--
作者：
L. Larsen;J. Harvey
流动水道中的碳固定和呼吸在全球和区域碳预算中发挥着重要作用，但土地利用和流域管理如何与时间扰动（风暴）相互作用，影响新陈代谢仍然知之甚少。在这里，我们结合联合收割机长期与天气采样的代谢及其变量控制在邻近流域的切萨皮克湾，以解决限制因素和关键的时间尺度与恢复干扰。我们发现，相对于河流连续体概念的预测，焦点流“破坏”碳循环，碳平衡接近于零，在某些情况下，初级生产总值（GPP）和生态系统呼吸（ER）之间的耦合更紧密，归因于碳限制。碳成为限制ER的闪光风暴水文和简化的通道地貌抑制了细泥沙的积累。时间尺度的香农熵分析表明，细颗粒沉积物在4 - 6个月内充当营养物质和碳的时间释放胶囊，促进生物地球化学转化。通过水力扰动损失的细粉对GPP的影响长达30天，对具有碳限制的流中的ER的影响长达50天。相反，GPP和ER没有紧密耦合，恢复发生在1天内。结果表明，营养和碳的限制和机械和化学干扰之间的复杂的相互作用，管理模式和破坏城市河流中的碳循环的后果。碳限制和紧密的GPP/ER耦合增强了河流生态系统功能的脆弱性，但最佳的管理实践，以减少暴雨流量和通道地貌多样性为目标，可以打破这种耦合，最大限度地减少碳循环中断。
Carbon fixation and respiration in flowing waterways play significant roles in global and regional carbon budgets, yet how land use and watershed management interact with temporal disturbances (storms) to influence metabolism remains poorly understood. Here, we combine long‐term with synoptic sampling of metabolism and its variable controls in neighboring watersheds of the Chesapeake Bay to resolve limiting factors and critical timescales associated with recovery from disturbance. We found that, relative to predictions of the river continuum concept, focal streams have “disrupted” carbon cycles, with carbon balances closer to zero, and, in some cases, tighter coupling between gross primary production (GPP) and ecosystem respiration (ER), attributable to carbon limitation. Carbon became limiting to ER where flashy storm hydrographs and simplified channel geomorphology inhibited accumulation of fine sediment. Shannon entropy analysis of timescales revealed that fine sediment served as a time‐release capsule for nutrients and carbon over 4–6 months, fueling biogeochemical transformations. Loss of fines through hydraulic disturbance had up to 30‐d impacts on GPP and 50‐d impacts on ER in the stream with carbon limitation. In contrast, where GPP and ER were not tightly coupled, recovery occurred within 1 d. Results suggest that a complex interplay between nutrient and carbon limitation and mechanical and chemical disturbance governs patterns and consequences of disrupted carbon cycling in urban streams. Carbon limitation and tight GPP/ER coupling enhance the vulnerability of stream ecosystem functions, but best management practices that target stormflow reduction and channel geomorphic diversity can break that coupling and minimize carbon cycle disruptions.
DOI：
10.1016/j.scitotenv.2011.10.074
发表时间：
2012-09
期刊：
The Science of the total environment
影响因子：
--
作者：
M. Trimmer;J. Grey;C. Heppell;A. Hildrew;K. Lansdown;H. Stahl;G. Yvon‐Durocher
通讯作者：
M. Trimmer;J. Grey;C. Heppell;A. Hildrew;K. Lansdown;H. Stahl;G. Yvon‐Durocher
影响因子：
2.9
作者：
Walters, E.;Graml, M.;Horn, H.
通讯作者：
Horn, H.