Shading and sediment structure effects on stream metabolism resistance and resilience to infrequent droughts.
Shading and sediment structure effects on stream metabolism resistance and resilience to infrequent droughts.
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遮荫和沉积物结构对河流代谢抵抗力和对罕见干旱的恢复能力的影响
DOI：
10.1016/j.scitotenv.2017.10.105
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Michael
中科院分区：
文献类型：
--
作者：
Zlatanović;Fabian;Premke;Katrin;Michael
由于全球变暖和水需求增加导致的不定期干旱，预计常年、温带、低水位的溪流将变得断断续续。我们假设，由不规则干旱引起的河流新陈代谢变化与温带河流的遮荫和河床沉积物结构有关。我们设置了16条具有低或高遮荫条件的室外实验溪流和河床，河床要么是交替排列的砾石和沙子，要么是均匀的砾石和沙子混合沉积物结构。我们评估了群落呼吸(CR)、净生态系统生产量(NEP)和附生植物的生物量和结构(硅藻、绿藻、蓝藻)在6周的定殖期、6周的干燥期和2.5周的复湿后。在定殖和复湿阶段结束时，对微生物生物膜群落中的异养体与自养体(H：A)和真菌与细菌(F：B)的比例进行了评估。不同底泥结构的河流在功能上是相似的；它们在干燥状态下的新陈代谢仅受光照有效性的控制。在径流衰退期间，所有溪流均表现为净异养。随着干燥的进行，NEP和CR下降到零。干燥作用改变了周围植物的组成，从主要的硅藻转变为绿藻和蓝藻，特别是在低阴影和混合沉积物的溪流中。NEP在干旱后迅速恢复，在低遮荫下伴随着高蓝藻和绿藻的生长，而在高遮荫溪流中总附生植物的生长较差。与遮荫相关的H：A增加，与沉积物结构相关的F：B降低。与定植阶段相比，这些变化导致CR恢复率较低，表明CR恢复力与微生物组成变化之间存在联系。干旱影响、旱灾后恢复、遮荫程度和河床结构之间的联系揭示了气候和土地利用变化下低级河流管理的重要性，以减轻未来不可预测的罕见干旱对温带生态系统河流新陈代谢的影响。
Perennial, temperate, low-order streams are predicted to become intermittent as a result of irregular droughts caused by global warming and increased water demand. We hypothesize that stream metabolism changes caused by irregular droughts are linked to the shading and bed sediment structure of temperate streams. We set up 16 outdoor experimental streams with low or high shade conditions and streambeds either with alternating sorted patches of gravel and sand or homogeneous gravel-sand mix sediment structures. We assessed community respiration (CR), net ecosystem production (NEP) and periphyton biomass and structure (diatoms, green algae, cyanobacteria) in the course of 6 weeks colonization, 6 weeks desiccation, and 2.5 weeks after rewetting. The heterotroph to autotroph (H:A) and fungi to bacteria (F:B) ratios in the microbial biofilm community were assessed at the end of the colonization and rewetting phases. Streams with different bed sediment structure were functionally similar; their metabolism under desiccation was controlled solely by light availability. During flow recession, all streams showed net heterotrophy. As desiccation progressed, NEP and CR decreased to zero. Desiccation altered the periphyton composition from predominantly diatoms to green algae and cyanobacteria, particularly in streams with low shade and mixed sediments. Rapid post-drought resilience of NEP was accompanied by high cyanobacteria and green algae growth in low shade, but poor total periphyton growth in high shade streams. Variable periphyton recovery was followed by increased H:A in relation to shading, and decreased F:B in relation to sediments structure. These shifts resulted in poor CR recovery compared to the colonization phase, suggesting a link between CR resilience and microbial composition changes. The links between drought effects, post-drought recovery, shading level, and streambed structure reveal the importance of low-order stream management under a changing climate and land use to mitigate the future impact of unpredictable infrequent droughts on stream metabolism in temperate ecosystems.
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影响因子：
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作者：
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--
发表时间：
2010
期刊：
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影响因子：
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作者：
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DOI：
--
发表时间：
1987
期刊：
影响因子：
--
作者：
C. Peterson
通讯作者：
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