Faculty of Biology and Chemistry, Department of Marine Ecology, University of Bremen, UFT Building, Leobener Str. 6, 28359, Bremen, Germany.
College of Science and Engineering, James Cook University, 1 Angus Smith Drive, Douglas, QLD, 4814, Australia.
Sci Rep. 2022 Oct 6;12(1):16788. doi: 10.1038/s41598-022-21110-w.
The resistance of hard corals to warming can be negatively affected by nitrate eutrophication, but related knowledge for soft corals is scarce. We thus investigated the ecophysiological response of the pulsating soft coral Xenia umbellata to different levels of nitrate eutrophication (control = 0.6, medium = 6, high = 37 μM nitrate) in a laboratory experiment, with additional warming (27.7 to 32.8 °C) from days 17 to 37. High nitrate eutrophication enhanced cellular chlorophyll a content of Symbiodiniaceae by 168%, while it reduced gross photosynthesis by 56%. After additional warming, polyp pulsation rate was reduced by 100% in both nitrate eutrophication treatments, and additional polyp loss of 7% d and total fragment mortality of 26% was observed in the high nitrate eutrophication treatment. Warming alone did not affect any of the investigated response parameters. These results suggest that X. umbellata exhibits resistance to warming, which may facilitate ecological dominance over some hard corals as ocean temperatures warm, though a clear negative physiological response occurs when combined with nitrate eutrophication. This study thus confirms the importance of investigating combinations of global and local factors to understand and manage changing coral reefs.
硬珊瑚对变暖的抵抗力可能会受到硝酸盐富营养化的负面影响，但有关软珊瑚的相关知识却很少。因此，我们在实验室实验中研究了脉动软珊瑚 Xenia umbellata 对不同水平硝酸盐富营养化（对照=0.6、中=6、高=37 μM 硝酸盐）的生态生理反应，从第 17 天到第 37 天还进行了额外的升温（27.7 至 32.8°C）。高硝酸盐富营养化使共生藻细胞叶绿素 a 含量增加了 168%，而总光合作用则降低了 56%。在额外升温后，两种硝酸盐富营养化处理中珊瑚虫的息肉搏动率都降低了 100%，在高硝酸盐富营养化处理中还观察到息肉损失增加了 7% d 和总碎片死亡率增加了 26%。单独升温对所有研究的反应参数均无影响。这些结果表明，X. umbellata 对变暖表现出抵抗力，这可能使其在海洋温度变暖时相对于某些硬珊瑚具有生态优势，尽管与硝酸盐富营养化结合时会产生明显的负面生理反应。因此，本研究证实了调查全球和地方因素组合的重要性，以了解和管理不断变化的珊瑚礁。
