Effects of combined climate change stressors on coral reef fish offspring

人为气候变化已经影响到地球的生态系统，特别是世界海洋。在这里，温度升高、海洋酸化和缺氧或缺氧地区，除其他因素外，影响海洋生物的生长和生存。在气候变化的背景下，海洋环境条件稳定，季节变化不太明显，对当地生物构成越来越大的挑战，因为它们的生理耐受阈值往往变化不大，或已经达到极限。模拟预测环境情景的实验方法可以帮助揭示这些海洋生物如何改变代谢过程，这是生物适应性的关键，因此它们可以科普未来甚至可能更极端的条件。然而，只有很少的研究测试的耦合效应的上述三个压力，特别是关于海洋鱼类。其种群大小与渔业一样，受其幼虫的补充和存活控制，这可能增加气候变化影响的环境因素对种群动态的重要性。因此，拟议项目旨在调查温度升高、海洋酸化和缺氧对珊瑚礁鱼类特别脆弱的生命早期阶段的生态生理参数的相互作用和影响。两组实验将深入了解肉桂小丑鱼（Amphiprion melanopus）的幼虫，大堡礁（澳大利亚）的一个关键物种，对预测和模拟环境条件的反应。为此，将研究温度升高、海洋酸化和缺氧之间的相互作用对代谢相关性状的影响，包括个体鱼的耗氧率、游泳能力、生长和状况。然后，进一步的测量，包括鳃结构和表面分析，以及有氧和无氧代谢酶的活动将有助于完成生物体在组织和细胞水平上的反应。这两组实验涵盖了整个幼虫发育过程--从孵化到变态后--以确定鱼类可能面临最大风险的窗口，并支持对早期生命史在不久的将来环境条件下受到影响的全面理解。这种新颖而全面的方法为海洋鱼类生物多样性的保护提供了巨大的潜力。此外，该项目有望进一步研究使用模型的方法，从理论上将生理结果从生物体提升到种群水平。这种模式也可适用于其他系统，例如，正在努力支持可持续渔业的温带地区的商业物种。

Anthropogenic climate change is already affecting the planet’s ecosystems, in particular the world’s oceans. Here, elevated temperatures, ocean acidification and deoxygenated or hypoxic areas affect, amongst other factors, the growth and survival of marine organisms. Against the backdrop of climate change, marine environments with stable conditions and less pronounced seasonal variability pose an increasing challenge for local organisms as their physiological tolerance thresholds are often less variable or already at their limits. Experimental approaches, simulating projected environmental scenarios, can help shed light on how these marine organisms modify metabolic processes, which are key to biological fitness, so they can cope with future and likely even more extreme conditions. However, there are only few studies testing the coupled effects of the three aforementioned stressors, especially with regard to marine fishes. Their population sizes are, next to fisheries, controlled by the recruitment and survival of their larvae which potentially increases the significance of climate-change affected environmental factors for population dynamics. Hence, the proposed project aims at investigating the interaction and effects of increased temperature, ocean acidification and hypoxia on eco-physiological parameters of the particularly vulnerable early life stages of coral reef fishes. Two sets of experiments will give insight in how larvae of the cinnamon clownfish (Amphiprion melanopus), a key species at the Great Barrier Reef (Australia), respond to projected and simulated environmental conditions. For this, the interaction between increased temperatures, ocean acidification and hypoxia will be investigated on metabolically relevant traits, including oxygen consumption rates, swimming performance, growth and condition, in individual fish. Then, further measurements including a gill structure and surface analysis, as well as aerobic and anaerobic metabolic enzyme activities will assist in completing the picture on how the organism is responding at the tissue and cellular levels. Both sets of experiments span the whole larval development – hatching to post-metamorphosis – to identify windows where fish may be most at risk and support a holistic understanding of how early life history is affected under near-future environmental conditions. This novel and comprehensive approach offers great potential for the conservation of marine fishes’ biodiversity. In addition, the project is promising for further research approaches using models to theoretically upscale the physiological results from an organismal to a population level. Such models could be applied to other systems as well, for example, commercial species from temperate latitudes where efforts are being made to support sustainable fisheries.