Fisheries College, Guangdong Ocean University, Zhanjiang, China.
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou 510301, China.
Mar Pollut Bull. 2021 Dec;173(Pt A):112932. doi: 10.1016/j.marpolbul.2021.112932. Epub 2021 Sep 14.
Marine heatwaves (MHWs) have occurred with increasing duration, frequency and intensity in the past decade in the South China Sea, posing serious threats to marine ecosystems and fisheries. However, the impact of MHWs on marine bivalves - one of the most ecologically and economically important fauna in coastal ecosystems - remains largely unknown. Here, we investigated physiological responses of the pearl oyster, Pinctada maxima inhabiting a newly identified climate change hotspot (Beibu Gulf, South China Sea) to short-lasting and repeatedly-occurring MHWs scenarios. Following 3-day exposure to short-lasting MHWs scenarios with water temperature rapidly arising from 24 °C to 28 °C, 32 °C and 36 °C, respectively, mortality rates of pearl oysters increased, and especially they suffered 100% mortality at 36 °C. Activities of enzymes including acid phosphatase (ACP), alkaline phosphatase (AKP), glutathione (GSH) and level of malondialdehyde (MDA) increased significantly with increasing intensity and duration of MHWs, indicating thermal stress responses. When exposed to repeatedly-occurring MHWs scenarios, mortality rates of pearl oysters increased slightly, and thermal stress responses were alleviated, as exemplified by significant decreases in ACP, AKP, GSH and MDA activities compared with those during short-lasting MHWs scenarios, demonstrating the potential of P. maxima to acclimate rapidly to MHWs. These findings advance our understanding of how marine bivalves respond to MHWs scenarios varying in duration, frequency, and intensity.
在过去十年中，南海的海洋热浪（MHWs）持续时间、频率和强度都有所增加，对海洋生态系统和渔业造成了严重威胁。然而，海洋双壳贝类——沿海生态系统中最重要的生态和经济动物之一——受到 MHW 的影响在很大程度上仍然未知。在这里，我们研究了栖息在新确定的气候变化热点（南海北部湾）的珍珠贝（Pinctada maxima）对短暂且反复发生的 MHW 情景的生理反应。在经历了为期 3 天的短暂 MHW 情景暴露后，水温分别迅速从 24°C 上升到 28°C、32°C 和 36°C，珍珠贝的死亡率上升，特别是在 36°C 时死亡率达到 100%。酶的活性，包括酸性磷酸酶（ACP）、碱性磷酸酶（AKP）、谷胱甘肽（GSH）和丙二醛（MDA）的水平，随着 MHW 的强度和持续时间的增加而显著增加，表明存在热应激反应。当暴露于反复发生的 MHW 情景时，珍珠贝的死亡率略有增加，热应激反应得到缓解，例如 ACP、AKP、GSH 和 MDA 活性与短暂 MHW 情景相比显著降低，表明 P. maxima 有迅速适应 MHW 的潜力。这些发现增进了我们对海洋双壳贝类如何应对持续时间、频率和强度不同的 MHW 情景的理解。
