International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China.
Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China.
Sci Total Environ. 2020 Jun 20;722:138001. doi: 10.1016/j.scitotenv.2020.138001. Epub 2020 Mar 17.
Ocean acidification and hypoxia are concurrent in some coastal waters due to anthropogenic activities in the past decades. In the natural environment, pH and dissolved oxygen (DO) may fluctuate and follow diel-cycling patterns, but such effects on marine animals have not been comprehensively studied compared to their constant effects. In order to study the effects of diel-cycling seawater acidification and hypoxia on the fitness of marine bivalves, the thick shell mussels Mytilus coruscus were exposed to two constant levels of dissolved oxygen (2 mg/L, 8 mg/L) under two pH treatments (7.3, 8.1), as well as single diel fluctuating pH or DO, and the combined diel fluctuating of pH and DO for three weeks. The experimental results showed that constant acidification and hypoxia significantly reduced the extracellular pH (pH) and condition index (CI) of mussels, and significantly increased HCO, pCO and standard metabolic rate (SMR). Diel fluctuating hypoxia and acidification also significantly reduced the pH and CI, and significantly increased pCO and SMR, but had no significant effects on HCO. However, the diel-cycling acidification and hypoxia resulted in a higher CI compared to continuous exposure. In general, continuous and intermittent stress negatively impact the hemolymph and growth performance of mussels. However, mussels possess a little stronger resistance to diel-cycling seawater acidification and hypoxia than sustained stress.
由于过去几十年的人为活动，海洋酸化和缺氧在一些沿海水域同时发生。在自然环境中，pH 值和溶解氧 (DO) 可能会波动，并遵循昼夜循环模式，但与持续影响相比，这些影响对海洋动物的研究还不够全面。为了研究昼夜循环海水酸化和缺氧对海洋双壳类动物适应能力的影响，厚壳贻贝 Mytilus coruscus 在两种 pH 值处理（7.3、8.1）下暴露于两种恒定的溶解氧水平（2 mg/L、8 mg/L），以及单一昼夜波动的 pH 值或 DO 值，以及 pH 值和 DO 值的昼夜波动组合，持续三周。实验结果表明，持续酸化和缺氧显著降低了贻贝的细胞外 pH 值 (pH) 和条件指数 (CI)，并显著增加了 HCO、pCO 和标准代谢率 (SMR)。昼夜波动的缺氧和酸化也显著降低了 pH 值和 CI 值，并显著增加了 pCO 和 SMR 值，但对 HCO 没有显著影响。然而，昼夜循环酸化和缺氧导致 CI 值比连续暴露时更高。总的来说，持续和间歇性的应激会对贻贝的血淋巴和生长性能产生负面影响。然而，贻贝对昼夜循环海水酸化和缺氧的抵抗力比持续应激更强。
