Physiological and Biogeochemical Responses of Super-Corals to Thermal Stress from the Northern Gulf of Aqaba, Red Sea
Physiological and Biogeochemical Responses of Super-Corals to Thermal Stress from the Northern Gulf of Aqaba, Red Sea
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DOI：
10.3389/fmars.2017.00215
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发表时间：
2017-01-01
影响因子：
3.7
通讯作者：
Winters, Gidon
中科院分区：
文献类型：
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作者：
Grottoli, Andrea G.;Tchernov, Dan;Winters, Gidon
大规模珊瑚白化的频率和严重程度都在增加，导致珊瑚数量和多样性的丧失。然而，有些珊瑚比其他珊瑚更不易受漂白的影响，可以提供一个模型，用于确定珊瑚对热应力的恢复力所依据的生理和生物地球化学特征。来自北方红海亚喀巴湾埃拉特的珊瑚不会漂白，除非海水温度持续在夏季平均最高温度以上+6摄氏度或更高。这种极端的耐热性使它们有资格成为超级珊瑚，因为大多数珊瑚在暴露于仅比其最高温度高出1 - 2摄氏度的温度时会漂白。在这里，我们进行了一个受控的漂白实验（+61摄氏度）37天（相当于32度加热周）的三种珊瑚从帽子：Stylophora pistillata，Pocillopora damicornis和Favia favus。为了评估全生物对热应力的反应，在每个珊瑚上测量了以下变量：内共生藻细胞密度、叶绿素a、内共生有丝分裂细胞、总脂质、蛋白质、碳水化合物、骨架的稳定碳（δ C-13）和氧（00）同位素组成以及动物宿主组织和内共生藻的δ C-13。虽然所有三个物种出现明显的漂白，他们的生理和地球化学反应的物种特异性。S. pistillata分解代谢脂质，但仍保持总能量储备和生物量。骨骼δ C-13和δ O-18的增加表明该物种的钙化减少。P damicornis是受漂白的影响最小。它保持其总能量储备和生物量，同位素证据表明，它保持钙化，并不依赖于异养满足代谢需求时漂白。最后，蚕豆分解蛋白质和碳水化合物，并遭受损失的总能量储备和生物量。尽管如此，同位素证据表明，光合作用和钙化被维持，并且该物种具有较高的基线异养能力。因此，就像它们的非超级珊瑚同类一样，
Mass coral bleaching is increasing in frequency and severity, leading to the loss of coral abundance and diversity. However, some corals are less susceptible to bleaching than others and can provide a model for identifying the physiological and biogeochemical traits that underlie coral resilience to thermal stress. Corals from Eilat in the Gulf of Aqaba in the northern Red Sea do not bleach unless seawater temperatures are sustained at +6 degrees C or higher above their average summer maximum. This extreme thermal tolerance qualifies these as super-corals, as most corals bleach when exposed to temperatures that are only +1-2 degrees C above their thermal maximum. Here, we conducted a controlled bleaching experiment (+61 degrees C) for 37 days (equivalent to 32 degrees heating weeks) on three species of corals from Hat: Stylophora pistillata, Pocillopora damicornis, and Favia favus. To assess the response of the holobiont to thermal stress, the following variables were measured on each coral: endosymbiotic algal cell density, Chlorophyll a, endosymbiotic mitotic cell division, total lipids, protein, carbohydrate, and the stable carbon (delta C-13) and oxygen (00) isotopic composition of the skeleton and the delta C-13 of the animal host tissue and endosymbiotic algae. While all three species appeared visibly bleached, their physiological and biogeochemical responses were species-specific. S. pistillata catabolized lipids but still maintained total energy reserves and biomass. Increases in both skeletal delta C-13 and delta O-18 indicates that calcification declined in this species. P damicornis was the least affected by bleaching. It maintained its total energy reserves and biomass, and isotopic evidence suggests that it maintained calcification and was not dependent on heterotrophy for meeting metabolic demand when bleached. Finally, F favus catabolized protein and carbohydrates, and suffered losses in total energy reserves and biomass. Nevertheless, isotopic evidence suggest that photosynthesis and calcification were maintained, and that this species has a high baseline heterotrophic capacity. Thus, just like their non-super-coral conspecific counterparts, maintaining energy reserves