Hernando-Morales Víctor, Ameneiro Julia, Teira Eva
Biological Oceanography Group, Department of Ecology and Animal Biology, Faculty of Marine Science, University of Vigo, Vigo, 36200, Spain.
Marine Ecology and Zoology Group, Department of Ecology and Animal Biology, Faculty of Marine Science, University of Vigo, Vigo, 36200, Spain.
Environ Microbiol. 2017 Mar;19(3):1017-1029. doi: 10.1111/1462-2920.13538. Epub 2016 Oct 24.
Even though compelling evidences indicate that marine microbes show biogeographic patterns, very little is known on the mechanisms driving those patterns in aquatic ecosystems. In the present study, bacterial community structure was examined in epipelagic waters of a highly hydrodynamic area of the Southern Ocean to gain insight into the role that biogeochemical factors and water mass mixing (a proxy of dispersal) have on microbial biogeography. Four water masses that converge and mix around the South Shetland Islands (northern tip of the Antarctic Peninsula) were investigated. Bacterioplankton communities were water-mass specific, and were best explained by dispersal rather than by biogeochemical factors, which is attributed to the relatively reduced environmental gradients found in these cold and nutrient rich waters. These results support the notion that currents and water mixing may have a considerable effect in connecting and transforming different water bodies, and consequently, in shaping communities of microorganisms. Considering the multidimensional and dynamic nature of the ocean, analysis of water mass mixing is a more suitable approach to investigate the role of dispersal on the biogeography of planktonic microorganisms rather than geographical distance.
尽管有确凿的证据表明海洋微生物呈现出生物地理格局，但对于驱动水生生态系统中这些格局的机制却知之甚少。在本研究中，对南大洋一个水动力很强的区域的上层水域中的细菌群落结构进行了研究，以深入了解生物地球化学因素和水体混合（一种扩散的替代指标）在微生物生物地理学中所起的作用。对在南设得兰群岛（南极半岛北端）周围汇聚和混合的四个水体进行了调查。浮游细菌群落具有水体特异性，并且用扩散而非生物地球化学因素能最好地解释，这归因于在这些寒冷且营养丰富的水域中发现的相对较小的环境梯度。这些结果支持了这样一种观点，即洋流和水体混合可能在连接和转变不同水体方面具有相当大的影响，因此，在塑造微生物群落方面也有相当大的影响。考虑到海洋的多维和动态性质，分析水体混合是一种更合适的方法，用于研究扩散对浮游微生物生物地理学的作用，而不是地理距离。
