Will rising pCO2 levels in the ocean affect growth and survival of marine fish early life stages?

智力优点：海洋酸化有可能影响范围广泛的海洋生物，从而改变我们海洋的组成和功能。与钙化的海洋无脊椎动物相反，人们普遍认为海洋鱼类不受未来二氧化碳浓度的影响。虽然对于幼鱼和成鱼阶段可能是这样，但高二氧化碳海洋中鱼胚胎和幼体的命运不太确定，因为这些阶段的二氧化碳敏感性数据基本上无法获得。认识到这一知识差距，并受到最近两项关于小丑鱼和海鲈鱼幼虫的研究结果的启发，（Munday等人，PNAS 107（2010）; Checkley等人Science 324（2009）），研究人员进行了一系列实验，（Menidia beryllina）对升高的二氧化碳水平的影响，同时严格遵守目前海洋酸化研究的“最佳实践”准则。在1，000 ppm CO2时，平均M.与当前的CO2水平（390 ppm）相比，beryllina孵化后约1周的存活率显著且一致（5个实验）下降了约75%，而新孵化的幼虫的平均长度下降了22%。与先前的研究一起，这些结果表明，鱼类早期生命阶段对预计在本世纪发生的二氧化碳增加的敏感性高得惊人。鉴于包括大多数商业鱼种在内的许多鱼类种群的丰度往往受到影响早期生命史生长和存活的过程的调节，海洋酸化可能影响未来鱼类种群的动态，并成为可持续渔业的又一挑战。研究人员认为，现在迫切需要更好地了解二氧化碳如何影响海洋中鱼类胚胎和幼虫的生存能力。这需要新的方法，包括在多个物种之间进行更长期，更大规模的实验。研究人员将全面研究当前和未来二氧化碳水平（400 - 1,000 ppm）对三种模式鱼类卵和幼虫阶段的影响：大西洋银鱼（M。menidia）、内陆银汉鱼M. beryllina）和羊头米诺鱼（Cyprinodon variegatus）。他们还将调查同一物种的种群（M。不同的纬度。这些物种/种群具有重要的生态意义，因为它们处于中间营养地位，具有与商业海洋鱼类相当的生活史，在遗传生长能力和假定的敏感性方面存在差异，并且非常适合实验室实验。将在不同CO2、温度（21、27°C）和摄食条件（低，随意）下进行的实验中测量存活和生长（基于体重和身长），从而允许将CO2的影响与热应激和食物限制平行考虑。摄食率、总生长效率和耗氧量的量化将表征高CO2环境的生理成本。仔鱼耳石和骨骼元素的钙化的变化将从重量和Ca 45放射性示踪剂的方法来确定。最后，幸存的M。menidia（或M. beryllina）将被饲养至成熟，它们的后代将受到不同水平的CO2的挑战。在几代人中重复这种方法将证明CO2抗性通过自然选择可能进化的程度。总的来说，这项研究将取得重大进展，了解海洋酸化如何可能挑战世界上最宝贵的海洋资源，fish.Broader影响：这项调查将作为斯托尼布鲁克大学博士生的论文题目，并将支持一名女博士后研究员。PI在支持教育多样性和丰富本科和中学教育和研究方面有着良好的记录，并将继续为该项目采取这些做法。一个新的推广计划有可能达到100万水族馆顾客在项目期间。

Intellectual merit: Ocean acidification has the potential to affect a broad spectrum of marine organisms and thereby transform the composition and function of our oceans. In contrast to calcifying marine invertebrates, marine fish are widely believed to be unaffected by the CO2 concentrations projected for the future. While this may be so for juvenile and adult fish stages, the fate of fish embryos and larvae in high CO2 oceans is less certain as CO2-sensitivity data for these stages are largely unavailable. Recognizing this knowledge gap and inspired by the findings of two recent studies on clownfish and sea bass larvae (Munday et al. PNAS 107 (2010); Checkley et al. Science 324 (2009)), the investigators performed a series of experiments exposing eggs and early larvae of inland silversides (Menidia beryllina) to elevated CO2 levels while strictly adhering to current "best practice" guidelines for ocean acidification research. At 1,000 ppm CO2, average M. beryllina survival ~1wk post-hatch significantly and consistently (five experiments) declined by ~75% compared to current day CO2 levels (390 ppm), while average length of newly hatched larvae decreased by 22%. Together with prior studies, these results suggest a surprisingly high susceptibility of fish early life stages to the CO2 increases that are projected to occur this century. Given that the abundance of many fish stocks, including most commercial species, is often regulated by processes affecting early life history growth and survival, ocean acidification may impact the dynamics of future fish populations and become yet another challenge to sustainable fisheries. The investigators believe that there is now a pressing need to better understand how CO2 affects the viability of fish embryos and larvae in the ocean. This requires novel approaches involving longer-term, larger-scale experiments across multiple species. The investigators will comprehensively examine the impacts of current and future CO2 levels (400 - 1,000 ppm) during the egg and larval stages of three model fish species: Atlantic silversides (M. menidia), inland silversides (M. beryllina) and sheepshead minnows (Cyprinodon variegatus). They will also investigate populations of the same species (M. menidia) from differing latitudes. These species/populations are ecologically important due to their intermediate trophic position, have comparable life histories to commercial marine fish, offer differences in genetic growth capacity and presumed sensitivity, and are highly amenable to laboratory experimentation. Survival and growth (weight- and length-based) will be measured in experiments performed at different CO2, temperature (21, 27°C) and feeding conditions (low, ad libitum), thus permitting the affects of CO2 to be considered in parallel with thermal stress and food limitation. Quantification of feeding rates, gross growth efficiency, and oxygen consumption will characterize the physiological costs of high CO2 environments. Changes in calcification of larval fish otoliths and skeletal elements will be determined from weights and a Ca45 radiotracer approach. Finally, surviving M. menidia (or M. beryllina) will be reared to maturity and their offspring will be challenged with differing levels of CO2. Repeating this approach over several generations will demonstrate the extent to which CO2 resistance may evolve through natural selection. Collectively, this study will make significant advances toward understanding how ocean acidification may challenge the world's most valuable marine resource, fish.Broader Impacts: This investigation will serve as the dissertation topic for a doctoral student at Stony Brook University and will support a female post-doctoral researcher. The PIs have a strong record of supporting diversity in education and in enriching undergraduate and secondary school education and research and will continue these practices for this project. A novel outreach program has the potential to reach one million aquarium patrons during the project.