A Dissolved Oxygen Threshold for Shifts in Bacterial Community Structure in a Seasonally Hypoxic Estuary.
A Dissolved Oxygen Threshold for Shifts in Bacterial Community Structure in a Seasonally Hypoxic Estuary.
复制标题
DOI：
10.1371/journal.pone.0135731
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Horner-Devine MC
中科院分区：
文献类型：
--
作者：
Spietz RL;Williams CM;Rocap G;Horner-Devine MC
由于自然过程和人为影响，远洋生态系统可能会耗尽溶解氧。随着溶解氧浓度的降低，能量从大型动物转移到微生物，微生物在这些缺氧区持续存在。氧气限制区正在全球范围内迅速扩大；然而，与溶解氧梯度相关的微生物群落格局尚未得到很好的了解。为了评估溶解氧减少对细菌的影响，我们研究了美国华盛顿州胡德运河−冰峡湾状水体细菌群落结构随时间和空间的变化，该水体经历了季节性的低溶解氧水平，已知对鱼类和其他海洋生物有害。我们发现细菌丰富度和溶解氧之间存在很强的负相关关系。所有样品的细菌群落组成也与溶解氧梯度密切相关，当溶解氧浓度在5.18-7.12mgO2 L-1之间时，细菌群落组成发生了显著变化。溶解氧的这个阈值高于缺氧的经典定义(<；2.0mgO2 L-1)，这表明细菌群落的变化可能先于对生态和经济上重要的大型动物的有害影响。此外，负责推动整个群落变化的细菌分类群在其他氧气胁迫的生态系统中也经常被检测到，这表明我们在胡德运河中发现的模式可能与其他低氧生态系统相关。
Pelagic ecosystems can become depleted of dissolved oxygen as a result of both natural processes and anthropogenic effects. As dissolved oxygen concentration decreases, energy shifts from macrofauna to microorganisms, which persist in these hypoxic zones. Oxygen-limited regions are rapidly expanding globally; however, patterns of microbial communities associated with dissolved oxygen gradients are not yet well understood. To assess the effects of decreasing dissolved oxygen on bacteria, we examined shifts in bacterial community structure over space and time in Hood Canal, Washington, USA−a glacial fjord-like water body that experiences seasonal low dissolved oxygen levels known to be detrimental to fish and other marine organisms. We found a strong negative association between bacterial richness and dissolved oxygen. Bacterial community composition across all samples was also strongly associated with the dissolved oxygen gradient, and significant changes in bacterial community composition occurred at a dissolved oxygen concentration between 5.18 and 7.12 mg O2 L-1. This threshold value of dissolved oxygen is higher than classic definitions of hypoxia (<2.0 mg O2 L-1), suggesting that changes in bacterial communities may precede the detrimental effects on ecologically and economically important macrofauna. Furthermore, bacterial taxa responsible for driving whole community changes across the oxygen gradient are commonly detected in other oxygen-stressed ecosystems, suggesting that the patterns we uncovered in Hood Canal may be relevant in other low oxygen ecosystems.