School of Environment, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
Department of Medicine, The University of Chicago, Chicago, IL, United States.
Sci Rep. 2017 Feb 27;7:43600. doi: 10.1038/srep43600.
Deterioration of coral health and associated change in the coral holobiont's bacterial community are often a result of different environmental stressors acting synergistically. There is evidence that water flow is important for a coral's resistance to elevated seawater temperature, but there is no information on how water flow affects the coral-associated bacterial community under these conditions. In a laboratory cross-design experiment, Acropora muricata nubbins were subjected to interactive effects of seawater temperature (27 °C to 31 °C) and water flow (0.20 m s and 0.03 m s). In an in situ experiment, water flow manipulation was conducted with three colonies of A. muricata during the winter and summer, by partially enclosing each colony in a clear plastic mesh box. 16S rRNA amplicon pyrosequencing showed an increase in the relative abundance of Flavobacteriales and Rhodobacterales in the laboratory experiment, and Vibrio spp. in the in situ experiment when corals were exposed to elevated temperature and slow water flow. In contrast, corals that were exposed to faster water flow under laboratory and in situ conditions had a stable bacterial community. These findings indicate that water flow plays an important role in the maintenance of specific coral-bacteria associations during times of elevated thermal stress.
珊瑚健康状况恶化以及珊瑚共生体细菌群落的相关变化通常是多种环境胁迫协同作用的结果。有证据表明，水流对于珊瑚抵御海水升温非常重要，但对于在这些条件下水流如何影响珊瑚相关细菌群落，目前还没有相关信息。在一项实验室交叉设计实验中，我们将 nubbins 状的鹿角杯形珊瑚暴露于海水温度（27°C 至 31°C）和水流（0.20 m s 和 0.03 m s）的交互作用下。在一项现场实验中，我们在冬季和夏季通过部分用透明塑料网箱围住每个鹿角杯形珊瑚的方式来操纵水流，对三个鹿角杯形珊瑚的群体进行了水流处理。16S rRNA 扩增子焦磷酸测序结果表明，在实验室实验中，当珊瑚暴露于高温和低速水流时，Flavobacteriales 和 Rhodobacterales 的相对丰度增加，而在现场实验中，Vibrio spp.的相对丰度增加。相比之下，在实验室和现场条件下暴露于较快水流中的珊瑚具有稳定的细菌群落。这些发现表明，在高温胁迫期间，水流对于维持特定的珊瑚-细菌共生关系起着重要作用。
