The ecological impacts of multiple environmental stressors on coastal biofilm bacteria
The ecological impacts of multiple environmental stressors on coastal biofilm bacteria
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DOI：
10.1111/gcb.15626
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发表时间：
2021-04
影响因子：
11.6
通讯作者：
Robert M W Ferguson;Eoin J. O’Gorman;David J McElroy;B. McKew;R. A. Coleman;M. Emmerson;A. Dumbrell
中科院分区：
文献类型：
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作者：
Robert M W Ferguson;Eoin J. O’Gorman;David J McElroy;B. McKew;R. A. Coleman;M. Emmerson;A. Dumbrell
生态群落越来越多地暴露于多种相互作用的压力源。例如，气候变暖直接影响生物的生理机能，富营养化刺激了食物网的基础，收获更大的生物供人类食用阻碍了自上而下的控制。这些压力源通常在自然环境中结合在一起，产生不可预测的结果。沿海生态系统中的细菌群落是海洋食物网的基础，并提供许多重要的生态系统服务（如养分循环和碳固定）。然而，微生物群落将如何应对气候变化仍不确定。因此，我们采用交叉实验设计，利用海洋中生态系统来研究变暖、营养物富集和改变的顶级捕食者种群规模结构（普通岸蟹）对沿海微生物生物膜群落的影响。增温增加了细菌的α‐多样性（物种丰富度增加18%，均匀度增加67%），但这被营养物富集导致的α‐多样性减少所抵消（物种丰富度和均匀度分别减少14%和21%）。因此，我们表明，在气候变化情景下，这些压力源的一些影响可以相互抵消。变暖和顶级捕食者种群规模结构都影响了细菌生物膜群落的组成，变暖增加了能够增加溶解有机物和颗粒有机物矿化的细菌的丰度，如黄杆菌、鞘菌和噬细胞菌。然而，随着气候变暖，观察到的群落变化取决于顶端捕食者的种群规模结构，较小的螃蟹会增加鞘菌，而较大的螃蟹会增加噬细胞。这些变化可能会改变海岸生态系统中矿化和碳固存之间的平衡，导致变暖和二氧化碳产生之间的正反馈循环。我们的研究结果强调了变暖破坏沿海生态系统中微生物群落和生物地球化学循环的可能性，以及将这些影响与其他环境压力因素结合起来研究的重要性。
Ecological communities are increasingly exposed to multiple interacting stressors. For example, warming directly affects the physiology of organisms, eutrophication stimulates the base of the food web, and harvesting larger organisms for human consumption dampens top‐down control. These stressors often combine in the natural environment with unpredictable results. Bacterial communities in coastal ecosystems underpin marine food webs and provide many important ecosystem services (e.g. nutrient cycling and carbon fixation). Yet, how microbial communities will respond to a changing climate remains uncertain. Thus, we used marine mesocosms to examine the impacts of warming, nutrient enrichment, and altered top‐predator population size structure (common shore crab) on coastal microbial biofilm communities in a crossed experimental design. Warming increased bacterial α‐diversity (18% increase in species richness and 67% increase in evenness), but this was countered by a decrease in α‐diversity with nutrient enrichment (14% and 21% decrease for species richness and evenness, respectively). Thus, we show some effects of these stressors could cancel each other out under climate change scenarios. Warming and top‐predator population size structure both affected bacterial biofilm community composition, with warming increasing the abundance of bacteria capable of increased mineralization of dissolved and particulate organic matter, such as Flavobacteriia, Sphingobacteriia, and Cytophagia. However, the community shifts observed with warming depended on top‐predator population size structure, with Sphingobacteriia increasing with smaller crabs and Cytophagia increasing with larger crabs. These changes could alter the balance between mineralization and carbon sequestration in coastal ecosystems, leading to a positive feedback loop between warming and CO2 production. Our results highlight the potential for warming to disrupt microbial communities and biogeochemical cycling in coastal ecosystems, and the importance of studying these effects in combination with other environmental stressors.