Godefroid Mathilde, Gouveia Adriana, Otero-Ferrer Francisco, Espino Fernando, Tuya Fernando, Dubois Philippe
Marine Biology Laboratory, Université Libre de Bruxelles, Av. F.D. Roosevelt, CP 160/15, 1050, Bruxelles, Belgium.
BIOCON, IU-ECOAQUA, Parque Científico Tecnológico Marino de Taliarte, Universidad de Las Palmas de Gran Canaria, 35214, Gran Canaria, Spain; Department of Biology, University of Aveiro, 3810-193, Aveiro, Portugal.
J Therm Biol. 2023 Jul;115:103593. doi: 10.1016/j.jtherbio.2023.103593. Epub 2023 Jun 14.
Sensitivity to ocean warming is generally expected to be lower in populations from more heterogeneous thermal environments, owing to greater phenotypic plasticity and/or genotype selection. While resilience of benthic populations from thermally fluctuating environments has been investigated at a variety of spatial scales, this has received limited attention across depths and has remained unresolved for Antipatharian corals, key habitat-forming species across a wide bathymetric range in all of the world oceans. In this study, we aimed at addressing the thermal sensitivity of Antipatharian corals across depths characterized by different levels of temperature fluctuations. We used an acute ramping experimental approach to compare the thermal sensitivity of colonies of (1) the branched Antipatharian Antipathella wollastoni (Gray, 1857) from two distinct depths (25 and 40 m) in Gran Canaria (Canary Islands, Spain); and of (2) unbranched mesophotic (80 m) Stichopathes species, from Lanzarote (Canary Islands, Spain; S. gracilis (Gray, 1857)), and Stichopathes sp. clade C from Mo'orea, French Polynesia. Results showed that the daily temperature range in Gran Canaria was larger at mesophotic depths (3.9 °C vs. 2.8 °C at 40 and 25 m, respectively) and this coincided with lower thermal sensitivity in mesophotic colonies of A. wollastoni. Second, S. gracilis from Lanzarote showed a lower thermal sensitivity than the previously studied Stichopathes sp. clade C from Mo'orea (French Polynesia) inhabiting a less variable habitat. These results are in line with the climate variability hypothesis, which states that populations under more variable thermal conditions have a lower sensitivity to warming than those from more stable environments, as they have adapted/acclimated to these higher levels of temperature fluctuations.
由于具有更大的表型可塑性和/或基因型选择，通常预计来自更多样化热环境的种群对海洋变暖的敏感性较低。虽然已经在各种空间尺度上研究了来自热波动环境的底栖生物种群的恢复力，但在不同深度上这方面受到的关注有限，对于黑珊瑚（Antipatharian corals）这一在世界所有海洋广泛深度范围内形成关键栖息地的物种来说，这一问题仍未得到解决。在本研究中，我们旨在解决不同深度的黑珊瑚对热的敏感性问题，这些深度具有不同程度的温度波动。我们采用急性升温实验方法，比较了以下两类群体的热敏感性：（1）来自西班牙加那利群岛大加那利岛两个不同深度（25米和40米）的分支状黑珊瑚沃氏拟 antipathella wollastoni（Gray，1857）；以及（2）来自西班牙加那利群岛兰萨罗特岛（S. gracilis（Gray，1857））和法属波利尼西亚莫雷阿岛的C类分支的非分支中光层（80米）的Stichopathes物种。结果表明，大加那利岛中光层深度的日温度范围更大（分别为3.9°C，而40米和25米处为2.8°C），这与沃氏拟 antipathella wollastoni中光层群体较低的热敏感性相吻合。其次，来自兰萨罗特岛的S. gracilis比之前研究的来自法属波利尼西亚莫雷阿岛、栖息地变化较小的C类分支的Stichopathes物种表现出更低的热敏感性。这些结果与气候变率假说一致，该假说认为，处于更多变热条件下的种群对变暖的敏感性低于来自更稳定环境的种群，因为它们已经适应/驯化了这些更高水平的温度波动。
