In situ shifts of predominance between autotrophic and heterotrophic feeding in the reef-building coral Mussismilia hispida: an approach using fatty acid trophic markers
In situ shifts of predominance between autotrophic and heterotrophic feeding in the reef-building coral Mussismilia hispida: an approach using fatty acid trophic markers
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DOI：
10.1007/s00338-018-1692-z
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发表时间：
2018-05
期刊：
影响因子：
3.5
通讯作者：
M. Mies;A. Z. Güth;A. A. Tenorio-A.;T. N. S. Banha;L. Waters;P. S. Polito;S. Taniguchi;M. Bícego;P. Sumida
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文献类型：
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作者：
M. Mies;A. Z. Güth;A. A. Tenorio-A.;T. N. S. Banha;L. Waters;P. S. Polito;S. Taniguchi;M. Bícego;P. Sumida
许多造礁珊瑚是混合营养的，既依赖于甲藻共生体进行的光自养，也依赖于摄食浮游动物的异养。自养和异养向珊瑚提供特定的ω3脂肪酸，这些脂肪酸可以作为营养标记物，并记录每种摄食策略的贡献。这项研究通过监测宿主组织中的脂肪酸浓度，调查了巴西特有的造礁珊瑚Mussimilia hispida是否能够在以自养为主和以异养为主之间转换。然后，我们研究了变化是否与温度和风应力的变化有关。为此，对硬毛分枝杆菌进行了为期一年的监测，并每月采集组织样本。测定共生菌浓度，并进行油脂提取。用气相色谱-火焰离子化检测器定量分析了四种脂肪酸：自养标志硬脂酸(SDA)、二十二碳五烯酸(DPA)、二十二碳六烯酸(DHA)和异养标志顺式刚酸(CGA)。三个初步实验证实了SDA、DPA和CGA的特异性，而不是DHA的特异性。优势地位的转移在一年中发生了多次，并与最低温度和风应力有关。在夏季的几个月里，蜂群经历了轻微的漂白，它们似乎通过异养摄食来弥补这一点。我们的主要发现包括验证了三个FATM和一个珊瑚礁生态研究的营养指数，还描述了不同摄食模式之间的现场转换，同时强调了温度和气象事件的作用。
Many species of reef-building corals are mixotrophic, relying on both photoautotrophy performed by their dinoflagellate symbionts and heterotrophy from consumption of zooplankton. Autotrophy and heterotrophy supply corals with specificω3 fatty acids, which can be used as trophic markers and record the contribution of each feeding strategy. This study investigated whether the reef-building coralMussismilia hispida, endemic to Brazil, is able to shift between predominantly autotrophic and predominantly heterotrophic by monitoring the concentration of fatty acids in the host tissue. We then examined whether shifts are related to changes in temperature and wind stress. For that purpose,M. hispidacolonies were monitored for a year with monthly tissue sampling. Symbiont concentration was determined and lipid extraction performed. Four fatty acids were quantitatively analyzed by gas chromatography with flame ionization detector: the autotrophy markers: stearidonic acid (SDA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and a heterotrophy marker: cis-gondoic acid (CGA). Three preliminary experiments confirmed the specificity of SDA, DPA and CGA, but not of DHA. Shifts of predominance occurred multiple times during the year and were associated with minimal temperatures and wind stress. Colonies underwent mild bleaching during summer months, which they seemed to compensate with heterotrophic feeding. Our major findings include the validation of three FATM and a trophic index for coral reef ecology studies and also describing the in situ occurrences of shifts between feeding modes, while highlighting the role of temperature and meteorological events.