Sorbonne Université, UPMC Université Paris VI, IFD-ED 129, Paris Cedex 05, France; Centre Scientifique de Monaco, Coral Ecophysiology team, 8 Quai Antoine 1er, MC 98000, Monaco.
Centre Scientifique de Monaco, Coral Ecophysiology team, 8 Quai Antoine 1er, MC 98000, Monaco.
Mar Pollut Bull. 2021 Jun;167:112257. doi: 10.1016/j.marpolbul.2021.112257. Epub 2021 Mar 20.
Reef ecosystems are under increasing pressure from global and local stressors. Rising seawater temperature and high ultraviolet radiation (UVR) levels are the main drivers of the disruption of the coral-dinoflagellate symbiosis (bleaching). Bleaching can also be exacerbated by nitrate contamination in coastal reefs. However, the underlying physiological mechanisms are still poorly understood. Here, we assessed the physiological and oxidative state of the scleractinian coral Pocillopora damicornis, maintained eight weeks in a crossed-factorial design including two temperatures (26 °C or 30 °C), and two nitrate (0.5 and 3 μM-enriched), and UVR (no UVR and 25/1.5 Wm UVA/B) levels. Nitrate enrichment, and high temperature, significantly impaired coral photosynthesis. However, UVR alleviated the nitrate and temperature-induced decrease in photosynthesis, by increasing the coral's antioxidant capacity. The present study contributes to our understanding of the combined effects of abiotic stressors on coral bleaching susceptibility. Such information is urgently needed to refine reef management strategies.
珊瑚礁生态系统正受到全球和地方压力源的日益压力。海水温度升高和高水平的紫外线辐射（UVR）是破坏珊瑚虫共生关系（白化）的主要驱动因素。氮污染也会加剧沿海珊瑚礁的白化。然而，其潜在的生理机制仍知之甚少。在这里，我们评估了 scleractinian 珊瑚 Pocillopora damicornis 的生理和氧化状态，在包括两个温度（26°C 或 30°C）和两个硝酸盐（0.5 和 3 μM 富化）以及 UVR（无 UVR 和 25/1.5 Wm UVA/B）水平的交叉因子设计中维持了八周。硝酸盐富化和高温显著损害了珊瑚的光合作用。然而，UVR 通过增加珊瑚的抗氧化能力，缓解了硝酸盐和温度引起的光合作用下降。本研究有助于我们理解非生物胁迫因子对珊瑚白化易感性的综合影响。迫切需要此类信息来完善珊瑚礁管理策略。
