Organisms are increasingly likely to be exposed to multiple stressors repeatedly across ontogeny as climate change and other anthropogenic stressors intensify. Early life stages can be particularly sensitive to environmental stress, such that experiences early in life can “carry over” to have long-term effects on organism fitness. Despite the potential importance of these within-generation carryover effects, we have little understanding of how they vary across ecological contexts, particularly when organisms are re-exposed to the same stressors later in life. In coastal marine systems, anthropogenic nutrients and warming water temperatures are reducing average dissolved oxygen (DO) concentrations while also increasing the severity of naturally occurring daily fluctuations in DO. Combined effects of warming and diel-cycling DO can strongly affect the fitness and survival of coastal organisms, including the eastern oyster (Crassostrea virginica), a critical ecosystem engineer and fishery species. However, whether early life exposure to hypoxia and warming affects oysters' subsequent response to these stressors is unknown. Using a multiphase laboratory experiment, we explored how early life exposure to diel-cycling hypoxia and warming affected oyster growth when oysters were exposed to these same stressors 8 weeks later. We found strong, interactive effects of early life exposure to diel-cycling hypoxia and warming on oyster tissue : shell growth, and these effects were context-dependent, only manifesting when oysters were exposed to these stressors again two months later. This change in energy allocation based on early life stress exposure may have important impacts on oyster fitness. Exposure to hypoxia and warming also influenced oyster tissue and shell growth, but only later in life. Our results show that organisms' responses to current stress can be strongly shaped by their previous stress exposure, and that context-dependent carryover effects may influence the fitness, production, and restoration of species of management concern, particularly for sessile species such as oysters.

中文翻译：

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沿海生态系统工程师中缺氧和变暖的环境相关结转效应

随着气候变化和其他人为压力因素的加剧，生物体越来越有可能在个体发育过程中反复暴露于多种压力因素。生命早期阶段可能对环境压力特别敏感，因此生命早期的经历可以“延续”，对生物体健康产生长期影响。尽管这些代内遗留效应具有潜在的重要性，但我们对它们在生态环境中的变化知之甚少，尤其是当生物体在以后的生活中重新暴露于相同的压力源时。在沿海海洋系统中，人为营养物质和变暖的水温正在降低平均溶解氧 (DO) 浓度，同时也增加了 DO 自然发生的每日波动的严重程度。弗吉尼亚牡蛎)，一个关键的生态系统工程师和渔业物种。然而，生命早期暴露于缺氧和变暖是否会影响牡蛎对这些压力源的后续反应尚不清楚。使用多阶段实验室实验，我们探讨了当牡蛎在 8 周后暴露于这些相同的压力源时，生命早期暴露于循环缺氧和变暖如何影响牡蛎生长。我们发现生命早期暴露于循环缺氧和变暖对牡蛎组织的强烈交互影响：壳生长，这些影响取决于环境，只有当牡蛎在两个月后再次暴露于这些压力源时才会表现出来。这种基于生命早期压力暴露的能量分配变化可能对牡蛎的健康产生重要影响。暴露于缺氧和变暖也会影响牡蛎组织和壳的生长，但只有在以后的生活中。我们的研究结果表明，生物体对当前压力的反应会受到它们先前的压力暴露的强烈影响，并且依赖于环境的遗留效应可能会影响管理关注的物种的健康、生产和恢复，特别是对于牡蛎等固着物种。