ORCC: Collaborative Research: Mechanisms underpinning the unusual, high CO2 sensitivity of sand lances, key forage fishes on the Northwest Atlantic Shelf

海洋变暖和酸化是人为气候变化的直接、可预测的后果，可能对海洋生物造成巨大但仍未充分了解的后果。到目前为止，大多数被测试的鱼类物种对海洋酸化似乎只是轻微的敏感，但沙枪鱼是个例外。沙枪是一种小型的、类似鳗鱼的成群鱼类，在温带到极地生态系统中作为海鸟和哺乳动物的食物非常重要。最近的研究结论表明，在预测的未来海洋条件下，许多沙枪胚胎在发育和孵化方面存在困难。该项目使用现代实验和分子工具来确切地了解为什么沙枪胚胎如此异常敏感，以及哪些基因和酶对此负责。基因还将揭示某些特定的基因类型是否对变暖和酸化不那么敏感，然后可以用这些基因来预测物种是否会随着时间的推移进化成更耐受的物种。另一个重要的目标是测试一种关系密切的沙枪物种，以确定这一重要的饲料鱼群体是否普遍关注高度的气候敏感性。该项目结合了创新的生态、进化和基因组研究，帮助社会预测21世纪迫在眉睫的海洋生态系统变化，同时为下一代科学家配备必要的工具和专业知识，以成功应对未来的挑战。该项目还为康涅狄格州贫困学校的高中生创造了陪同团队前往斯特尔瓦根银行国家海洋保护区进行沙枪采样的机会。最近对北沙枪(Ammodytes Dubius)的两项研究有力地证明，预测未来的二氧化碳条件会导致受试鱼种胚胎存活率和孵化成功率出现迄今最严重的下降。该项目有四个目标，旨在揭示这种不同寻常的、对二氧化碳高度敏感的机制，以及这种现象的普遍性和遗传基础。[1]我们首次在因子CO2×温度条件下，将野生产卵者产生的杜比乌斯幼虫培育到后期幼虫阶段，以测试沙枪幼虫是否像胚胎一样对二氧化碳敏感。[2]我们将首次使用转录学工具(RNAseq，RT-qPCR)来阐明导致‘CO2损伤孵化’的机制，特别是孵化酶，以更好地了解新发现的鱼类因高二氧化碳而死亡的机制。[3]现代基因组方法(低覆盖率全基因组测序；等位基因频率漂移、相关性分析)将揭示沙枪对二氧化碳的高敏感性是否具有遗传基础，从而可能进化。[4]我们将首次将二氧化碳×温度实验扩展到同类的美国沙枪(A.americanus)，这提供了近岸和近海物种对二氧化碳敏感性的重要科学对比，并将得出关键的见解，即高二氧化碳敏感性是否是沙枪家族中更广泛关注的问题。该奖项是通过BIO/IOS组织应对气候变化计划和GEO/OCE生物海洋学计划共同资助的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ocean warming and acidification are direct, predictable consequences of anthropogenic climate change with likely vast but still insufficiently understood consequences for marine life. So far, most tested fish species appear only mildly sensitive to ocean acidification, but sand lances are an exception. Sand lances are small, eel-like, schooling fishes of enormous importance as food for seabirds and mammals in temperate to polar ecosystems. Recent research conclusively demonstrated that many sand lance embryos have trouble developing and hatching under predicted future ocean conditions. This project uses modern experimental and molecular tools to understand exactly WHY sand lance embryos are so unusually sensitive and which genes and enzymes are responsible for this. Genes will also reveal whether some specific genotypes are less sensitive to warming and acidification, which can then be used to predict whether the species could evolve to be more tolerant over time. Another important objective is to test a closely related sand lance species to find out whether the high climate sensitivity might be of general concern in this important group of forage fishes. This project combines innovative ecological, evolutionary, and genomic research to help society anticipate looming marine ecosystem changes in the 21st century, while equipping the next generation of scientists with the needed tools and expertise to succeed in the challenges ahead. The project also creates opportunities for high school students from underprivileged Connecticut schools to accompany the team on sand lance sampling trips to Stellwagen Bank National Marine Sanctuary. Two recent studies on Northern sand lance (Ammodytes dubius), a key forage fish on offshore sand banks across the Northwest Atlantic shelf, have robustly demonstrated that predicted future CO2 conditions induce some of the most severe reductions in embryo survival and hatching success seen yet among tested fish species. This project has four objectives for revealing the mechanisms underpinning this unusual, high CO2-sensitivity as well as the ubiquity and genetic basis of this phenomenon. [1] For the first time, we will rear A. dubius offspring produced from wild spawners to late larval stages at factorial CO2 × temperature conditions to test whether sand lance larvae are as CO2-sensitive as embryos. [2] For the first time, we will use transcriptomic tools (RNAseq, RT-qPCR) to elucidate mechanisms causing ‘CO2-impaired hatching’, focusing specifically on hatching enzymes, to better understand a newly discovered mortality mechanism due to high CO2 in fishes. [3] Modern genomic approaches (low-coverage whole genome sequencing; allele frequency shifts, relatedness analyses) will reveal whether high CO2-sensitivity has a genetic basis in sand lance and could therefore evolve. [4] And for the first time, we will extend CO2 × temperature experiments to a congener, the American sand lance (A. americanus), which provides an important scientific contrast between nearshore vs. offshore species CO2-sensitivities and will yield critical insights whether high CO2-sensitivity is a wider concern within the sand lance family. This award was co-funded through the BIO/IOS Organismal Responses to Climate Change Program and the GEO/OCE Biological Oceanography Program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.