State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; State Key Laboratory of Mariculture Breeding, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
State Key Laboratory of Marine Environmental Science, College of the Environmental and Ecology, Xiamen University, Xiamen 361102, China; State Key Laboratory of Mariculture Breeding, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; National Observation and Research Station for the Taiwan Strait Marine Ecosystem, Xiamen University, Zhangzhou, China.
Environ Res. 2024 Nov 1;260:119628. doi: 10.1016/j.envres.2024.119628. Epub 2024 Jul 22.
The widespread and severe drop in dissolved oxygen concentration in the open ocean and coastal waters has attracted much attention, but assessments of the impacts of environmental hypoxia on aquatic organisms have focused primarily on responses to current exposure. Past stress exposure might also affect the performance of aquatic organisms through carryover effects, and whether these effects scale from positive to negative based on exposure degree is unknown. We investigated the carryover effects of varying embryonic hypoxia levels (mediate hypoxia: 3.0-3.1 mg O/L; severe hypoxia: 2.0-2.1 mg O/L) on the fitness traits of adult Pacific abalone (Haliotis discus hannai), including growth, hypoxia tolerance, oxygen consumption, ammonia excretion rate, and biochemical responses to acute hypoxia. Moderate embryonic hypoxia exposure significantly improved the hypoxia tolerance of adult Pacific abalone without sacrificing growth and survival. Adult abalone exposed to embryonic hypoxia exhibited physiological plasticity, including decreased oxygen consumption rates under environmental stress, increased basal methylation levels, and a more active response to acute hypoxia, which might support their higher hypoxia tolerance. Thus, moderate oxygen declines in early life have persistent effects on the fitness of abalone even two years later, further affecting population dynamics. The results suggested that incorporating the carryover effects of embryonic hypoxia exposure into genetic breeding programs would be an important step toward rapidly improving the hypoxia tolerance of aquatic animals. The study also inspires the protection of endangered wild animals and other vulnerable species under global climate change.
开阔海域和沿海水域中溶解氧浓度的广泛而严重下降引起了广泛关注，但对环境缺氧对水生生物影响的评估主要集中在当前暴露的反应上。过去的压力暴露也可能通过持续效应影响水生生物的表现，并且这些效应是否根据暴露程度从正到负扩展尚不清楚。我们研究了不同胚胎缺氧水平（中度缺氧：3.0-3.1mg O/L；严重缺氧：2.0-2.1mg O/L）对成年太平洋鲍（Haliotis discus hannai）适应度特征的持续效应，包括生长、缺氧耐受性、耗氧量、氨排泄率以及对急性缺氧的生化反应。适度的胚胎缺氧暴露显著提高了成年太平洋鲍的缺氧耐受性，而不会牺牲生长和生存。暴露于胚胎缺氧的成年鲍表现出生理可塑性，包括在环境胁迫下降低耗氧量、增加基础甲基化水平以及对急性缺氧更活跃的反应，这可能支持它们更高的缺氧耐受性。因此，早期生命中适度的氧气下降对鲍鱼的适应度甚至在两年后仍有持续影响，进一步影响了种群动态。结果表明，将胚胎缺氧暴露的持续效应纳入遗传育种计划将是提高水生动物缺氧耐受性的重要一步。该研究还启发了在全球气候变化下保护濒危野生动物和其他脆弱物种。
