The Thirsty Eel: Summer and Winter Flow Thresholds that Tilt the Eel River of Northwestern California from Salmon-Supporting to Cyanobacterially Degraded States
The Thirsty Eel: Summer and Winter Flow Thresholds that Tilt the Eel River of Northwestern California from Salmon-Supporting to Cyanobacterially Degraded States
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DOI：
10.1643/ce-14-086
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发表时间：
2015-03
期刊：
影响因子：
2.6
通讯作者：
M. Power;Keith Bouma‐Gregson;Patrick Higgins;S. Carlson
中科院分区：
文献类型：
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作者：
M. Power;Keith Bouma‐Gregson;Patrick Higgins;S. Carlson
虽然鳗鱼河流经加州西北部的地区，这些地区被认为是水源相对充足的地区，但鳗鱼河越来越受到干旱和取水的压力。我们讨论了如何在夏季排放的关键阈值变化可能会倾斜鳗鱼从恢复鲑鱼支持生态系统对蓝藻降解。为了维持食物网和栖息地，支持鲑鱼和抑制有害的蓝藻，夏季排放必须足以连接mainstem池水文轻轻移动，凉爽的基地流。饲养鲑鱼和虹鳟鱼可以生存，即使在夏季低流量时成为孤立的池，如果潜流交换是足够的。但是，如果在夏季干旱期间维持河流流量的地下水排放量下降到临界水平以下，温暖的停滞条件将杀死鲑鱼，蓝细菌将茁壮成长。挑战和机遇恢复鳗鱼和提高其适应极端气候，水改道，和过量装载的细沉积物指向探索土地利用和陆地植被如何影响交付从高地的水，热，沉积物，溶质，有机物，和生物体的方式，要么治愈或破坏河流。
Although it flows through regions of northwestern California that are thought to be relatively well watered, the Eel River is increasingly stressed by drought and water withdrawals. We discuss how critical threshold changes in summer discharge can potentially tilt the Eel from a recovering salmon-supporting ecosystem toward a cyanobacterially degraded one. To maintain food webs and habitats that support salmonids and suppress harmful cyanobacteria, summer discharge must be sufficient to connect mainstem pools hydrologically with gently moving, cool base flow. Rearing salmon and steelhead can survive even in pools that become isolated during summer low flows if hyporheic exchange is sufficient. But if the ground water discharge that sustains river flow during summer drought drops below critical levels, warm stagnant conditions will kill salmonids, and cyanobacteria will thrive. Challenges and opportunities for restoring the Eel and increasing its resilience to climate extremes, water diversions, and excessive loading of fine sediments point toward exploring how land use and terrestrial vegetation affect delivery from uplands of water, heat, sediments, solutes, organic matter, and organisms—in ways that either heal or damage rivers.