摘要:海洋酸化和重金属污染作为全球性海洋环境问题，均影响海洋生物的生存和生态系统的健康。海月水母是近岸海域常见的胶质性浮游动物，其生长发育和种群数量易受到海洋环境变化的影响。研究海月水母碟状幼体对海洋酸化（pH 8.1和pH 7.6）和Cu²⁺（0、10 μg/L和25 μg/L）胁迫的生理响应，从氧化应激酶和酸碱平衡相关酶活性、呼吸、运动和生长等方面探究海洋酸化和铜污染对海月水母碟状幼体的综合影响。研究发现，经过16 d的暴露期后Cu²⁺对海月水母碟状幼体产生较强的毒性效应，抑制Ca²⁺-ATP酶和过氧化氢酶活性，造成超氧化物歧化酶活性和呼吸代谢速率异常升高、收缩频率降低、生长速度减慢。正常pH，25 μg/L铜暴露处理的超氧化物歧化酶活性和呼吸率最高，收缩频率和伞部直径最小。随着铜暴露浓度的增加，海洋酸化可以缓解Cu²⁺对海月水母呼吸率和生长的影响，但对Ca²⁺-ATP酶和过氧化氢酶活性具有协同抑制作用。确定了海洋酸化和Cu²⁺对海月水母的不同生理影响，这种差异影响可能会导致未来海洋生物多样性和生态系统的改变。



Abstract:Ocean acidification and heavy metal pollution are two global marine environmental problems, both of which have influences on the survival of marine organisms and the health of ecosystems. As a widely distributed glial zooplankton in the ocean, Aurelia coerulea plays an important role in biogeochemical cycle of important elements, such as carbon, nitrogen, and phosphorus. Many previous studies have reported the growth and population abundance of A. coerulea are susceptible to changes of the marine environment. In this study, the physiological response of A. coerulea ephyrae to ocean acidification (pH 8.1 and pH 7.6) and Cu²⁺ (0, 10 μg/L and 25 μg/L) stress was analyzed by measuring the activities of physiological metabolic enzymes including catalase (CAT), superoxide dismutase (SOD), Ca²⁺-ATPase, as well as respiration rates, pulsation rates and bell diameter of A. coerulea. The results showed that ocean acidification and Cu²⁺ stress had different effects on physiological indices of A. coerulea ephyrae. Cu²⁺ exposure can significantly inhibit the activities of CAT and Ca²⁺-ATPase, as well as the pulsation rates and growth rate of A. coerulea ephyrae. Besides, Cu²⁺ exposure can also lead to a significant increase in SOD activity and respiratory rate. While copper pollution might affect the swimming behavior of A. coerulea, leading to the significant decline in their predation ability and ontogeny. Furthermore, a negative correlation was observed between the bell diameter and Cu²⁺ concentration. Seawater acidification had an inhibitory effect on activity of CAT, SOD, and Ca²⁺-ATPase, as well as growth of A. coerulea ephyrae, and promoted its respiration. However, when A. coerulea ephyrae were exposed to co-exposure of seawater acidification and Cu²⁺, there were significant antagonistic effect between seawater acidification and Cu²⁺ on the growth and respiration of A. coerulea ephyrae. Our study indicates that the adaptability of A. coerulea ephyrae to copper pollution is enhanced with the background of ocean acidification. The different physiological effects of ocean acidification and Cu²⁺on A. coerulea identified in current study may lead to changes in marine biodiversity and ecosystems in the future.





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