Tilstra Arjen, Wijgerde Tim, Dini-Andreote Francisco, Eriksson Britas Klemens, Salles Joana Falcão, Pen Ido, Osinga Ronald, Wild Christian
Department of Marine Benthic Ecology & Evolution, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands.
Marine Ecology Group, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany.
PeerJ. 2017 Oct 11;5:e3802. doi: 10.7717/peerj.3802. eCollection 2017.
Recent research suggests that prior exposure of several months to elevated irradiance induces enhanced thermal tolerance in scleractinian corals. While this tolerance has been reported at the species level, individual coral colonies may react differently due to individual variability in thermal tolerance. As thermal anomalies are predicted to become common in the upcoming future, intraspecific variation may be key to the survival of coral populations. In order to study light-history based thermal stress responses on individual colonies, we developed a preliminary microcosm experiment where three randomly chosen, aquacultured colonies of the model coral were exposed to two irradiance treatments (200 and 400 μmol photons m s) for 31 days, followed by artificially induced heat stress (∼33.4 °C). We found different responses to occur at both the intraspecific and the intracolonial levels, as indicated by either equal, less severe, delayed, and/or even non-necrotic responses of corals previously exposed to the irradiance of 400 compared to 200 μmol photons m s. In addition, all individual colonies revealed light-enhanced calcification. Finally, elevated irradiance resulted in a lower chlorophyll concentration in one colony compared to the control treatment, and the same colony displayed more rapid bleaching compared to the other ones. Taken together, this study highlights the potential importance of intra-individual variability in physiological responses of scleractinian corals and provides recommendations for improving methodological designs for future studies.
近期研究表明，数月暴露于增强的辐照度下会使石珊瑚的耐热性增强。虽然这种耐受性已在物种层面得到报道，但由于耐热性存在个体差异，单个珊瑚群体的反应可能有所不同。由于预计热异常在未来将变得普遍，种内变异可能是珊瑚种群生存的关键。为了研究基于光照历史的单个群体对热应激的反应，我们开展了一项初步的微观实验，将随机选取的三个养殖的模式珊瑚群体暴露于两种辐照度处理（200和400 μmol光子·平方米·秒）下31天，随后进行人工诱导热应激（约33.4°C）。我们发现，与暴露于200 μmol光子·平方米·秒辐照度的珊瑚相比，先前暴露于400 μmol光子·平方米·秒辐照度的珊瑚出现了同等、较轻、延迟和/或甚至无坏死的反应，这表明在种内和群体内水平都出现了不同的反应。此外，所有单个群体都显示出光照增强钙化。最后，与对照处理相比，一个群体中辐照度升高导致叶绿素浓度降低，并且与其他群体相比，该群体显示出更快的白化现象。综上所述，本研究强调了石珊瑚生理反应中个体内变异的潜在重要性，并为改进未来研究的方法设计提供了建议。
