Easson Cole G, Lopez Jose V
Department of Biology, Middle Tennessee State University, Murfreesboro, TN, United States.
Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, United States.
Front Microbiol. 2019 Jan 4;9:3175. doi: 10.3389/fmicb.2018.03175. eCollection 2018.
The Gulf of Mexico (GoM) is a dynamic marine ecosystem influenced by multiple natural and anthropogenic processes and inputs, such as the intrusion of warm oligotrophic water via the Loop Current, freshwater and nutrient input by the Mississippi River, and hydrocarbon inputs via natural seeps and industrial spills. Microbial plankton communities are important to pelagic food webs including in the GoM but understanding the drivers of the natural dynamics of these passively distributed microorganisms can be challenging in such a large and heterogeneous system. As part of the DEEPEND consortium, we applied high throughput 16S rRNA sequencing to investigate the spatial and temporal dynamics of pelagic microbial plankton related to several environmental conditions during two offshore cruises in 2015. Our results show dramatic community shifts across depths, especially between photic and aphotic zones. Though we only have two time points within a single year, observed temporal shifts in microbial plankton communities were restricted to the seasonally influenced epipelagic zone (0-200 m), and appear mainly driven by changes in temperature. Environmental selection in microbial plankton communities was depth-specific, with variables such as turbidity, salinity, and abundance of photosynthetic taxa strongly correlating with community structure in the epipelagic zone, while variables such as oxygen and specific nutrient concentrations were correlated with community structure at deeper depths.
墨西哥湾（GoM）是一个动态的海洋生态系统，受到多种自然和人为过程及输入的影响，例如通过湾流侵入的温暖贫营养水、密西西比河的淡水和营养物质输入，以及通过天然渗漏和工业泄漏的碳氢化合物输入。微生物浮游生物群落对包括墨西哥湾在内的远洋食物网很重要，但在这样一个庞大且异质的系统中，了解这些被动分布的微生物自然动态的驱动因素可能具有挑战性。作为DEEPEND联盟的一部分，我们应用高通量16S rRNA测序来研究2015年两次近海航行期间与几种环境条件相关的远洋微生物浮游生物的时空动态。我们的结果显示，不同深度的群落发生了巨大变化，尤其是在光合层和无光层之间。尽管我们在一年内只有两个时间点，但观察到的微生物浮游生物群落的时间变化仅限于受季节影响的上层带（0-200米），并且似乎主要由温度变化驱动。微生物浮游生物群落的环境选择具有深度特异性，诸如浊度、盐度和光合类群丰度等变量与上层带的群落结构密切相关，而诸如氧气和特定营养物浓度等变量与较深深度的群落结构相关。
