Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan.
Fisheries Environment Research Department, Aichi Fisheries Research Institute, Gamagori, Aichi 443-0021, Japan.
Mar Environ Res. 2018 Jun;137:177-187. doi: 10.1016/j.marenvres.2017.12.019. Epub 2018 Jan 2.
Wind-induced upwelling of hypoxic waters containing hydrogen sulfide (HS) sometimes causes mass mortalities of aquatic organisms inhabiting coastal areas, including the hypoxia-tolerant Manila clam Ruditapes philippinarum. We examined the tolerance of Manila clam to HS under controlled laboratory conditions. Larvae and juveniles obtained by artificial fertilization or from a wild population were exposed to normoxic or to hypoxic water with or without un-ionized HS (concentrations, 0.2-52.2 mg/L). Twenty-four-hour exposure experiments revealed ontogenetic changes in the clam's tolerance to HS exposure: tolerance was enhanced from the larval stages to juveniles just after settlement but was attenuated as juveniles grew. Tolerance of larvae and juveniles to HS exposure weakened as the water temperature rose from 20 to 28 °C. Prolonged 48-h exposure to HS attenuated the tolerance of juveniles to HS. Temporary suspension of HS exposure by 24-h reoxygenation improved the ability of juveniles to withstand repeated HS exposure.
海风中卷涌起缺氧并含有硫化氢 (HS) 的海水，有时会导致栖息在沿海地区的水生生物大量死亡，包括耐缺氧的菲律宾蛤仔 Ruditapes philippinarum。我们在受控的实验室条件下研究了菲律宾蛤仔对 HS 的耐受性。通过人工受精或从野生种群中获得的幼虫和幼体被暴露于正常氧或缺氧水中，有无未离解的 HS（浓度为 0.2-52.2 mg/L）。24 小时暴露实验揭示了蛤仔对 HS 暴露的耐受性的个体发育变化：从幼虫阶段到刚定居的幼体，耐受性增强，但随着幼体的生长，耐受性减弱。幼虫和幼体对 HS 暴露的耐受性随着水温从 20°C 升高到 28°C 而减弱。长时间（48 小时）暴露于 HS 会减弱幼体对 HS 的耐受性。通过 24 小时复氧暂时停止 HS 暴露可提高幼体耐受重复 HS 暴露的能力。
