Dispersal, connectivity and local adaptation along an extreme environmental gradient

预计未来海洋温度的上升将对海洋生物产生深远和有害的后果。生物体必须要么迁移到更有利的环境，适应维持动态平衡，要么通过基因组变化来适应新的热力机制，否则就会发生局部灭绝。对于大量和完全久坐的海洋底栖生物来说，它们的迁徙能力取决于幼虫的扩散，这被假设在变暖的条件下是有限的。在这个项目中，研究小组研究了阿拉伯半岛东北部巨大的温度梯度上的四种海洋无脊椎动物(珊瑚、海胆、牡蛎和海鞘)的种群，将其作为一个自然系统来量化温度升高对扩散、遗传连接和适应的影响。该团队将使用一种综合方法，包括实验幼虫分析、生物物理建模和高通量测序技术。这项研究全面评估了气候变化对经济和生态重要生物的潜在影响，同时丰富了对核心生态和进化概念的理解。该项目的成功是与位于阿拉伯联合酋长国阿布扎比的纽约大学的协同国际合作的结果。这项研究项目为一名博士后学者、一名研究生和四名来自少数族裔群体的本科生提供指导和培训，他们对研究生教育感兴趣。这些学者中的每一位都有机会接触到尖端科学、国际和合作研究机会，以及向不同受众传播他们的科学的经验。此外，通过在当地一个科学博物馆实施两个外展，更广泛的影响延伸到北卡罗来纳州这一地区的夏洛特社区和更广泛的公众。了解扩散、遗传联系和适应之间的相互作用将是预测未来海洋温度上升对海洋底栖无脊椎动物影响的关键。该项目使用波斯湾/阿拉伯湾世界上最温暖的珊瑚礁作为一个模型系统，研究温度升高对这些生态和进化重要过程的影响，目前这些珊瑚礁的温度在下个世纪内在其他地方没有预料到的温度。来自波斯湾/阿拉伯湾的四种无脊椎动物的种群与邻近的阿曼湾的种群进行了比较，后者经历了更温和的热环境。第一个目的是描述温度升高对来自四个重点物种不同种群的幼虫沿温度梯度的存活、远洋持续时间和定居反应的影响。这些结果还与每个地点的女性在鸡蛋投资策略上的潜在变化进行了比较。第二个目的是使用从幼虫实验中收集的这些特定于种群的反应来参数化当前和未来的扩散模型，并将它们与现有的遗传连接模式进行比较。最终目的是通过全基因组比较和单代选择实验相结合，分析这些种群热适应的基因组基础，目的是确定在分类上截然不同的无脊椎动物物种中是否存在收敛/并行进化的证据。这个项目期望通过对温度对关键生命周期阶段的影响提供新的见解来促进我们对气候变化适应的了解，并阐明管理海洋无脊椎动物热适应的基因组过程。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。

Future increases in sea temperatures are expected to have far-reaching and detrimental consequences for marine organisms. Organisms must either move to more favorable environments, acclimate to maintain homeostasis, or adapt through genomic changes to the new thermal regime, otherwise local extinction will occur. For marine benthic organisms that are largely and completely sedentary, their capacity to migrate is dependent on larval dispersal, which is hypothesized to be limited under warming conditions. In this project, the research team studies populations of four marine invertebrate species (coral, sea urchin, oyster, ascidian) across the substantial thermal gradient along the northeastern Arabian Peninsula as a natural system to quantify the effects of elevated temperatures on dispersal, genetic connectivity and adaptation. The team will use an integrative approach that consists of experimental larval assays, biophysical modeling and high throughput sequencing technologies. This study provides a comprehensive assessment of the potential impacts of climate change on economically and ecologically important organisms, while enriching the understanding of core ecological and evolutionary concepts. The success of this project results from a synergistic international collaboration with New York University at Abu Dhabi, United Arab Emirates. This research project provides mentoring and training for a postdoctoral scholar, a graduate student, and four undergraduate students from underrepresented minority groups who are interested in pursuing graduate education. Each of these scholars is provided access to cutting-edge science, international and collaborative research opportunities, and experience disseminating their science to different audiences. Furthermore, the broader impacts extend to the Charlotte community and wider public in this region of North Carolina through the implementation of two outreach exhibits at a local science museum.Understanding the interplay between dispersal, genetic connectivity and adaptation will be key to forecasting the impacts on future sea temperature increases on marine benthic invertebrates. This project uses the world's warmest reefs in the Persian/Arabian Gulf, that currently experience temperatures not anticipated on reefs elsewhere within the next century, as a model system to study the effects of elevated temperatures on these ecologically and evolutionary important processes. Populations of four invertebrate species from the Persian/Arabian Gulf are compared to populations in the neighboring Gulf of Oman that experiences a more benign thermal environment. The first aim characterizes the impact of elevated temperatures on the survival, pelagic duration, and settlement responses of larvae from different populations of the four focal species along the thermal gradient. These results are additionally compared with potential shifts in egg investment strategies by females from each location. The second aim uses these population-specific responses gleaned from the larval experiments to parameterize models of present day and future dispersal and compares them against existing patterns of genetic connectivity. The final aim analyzes the genomic basis for thermal adaptation in these populations through a combination of whole genome comparisons and single-generation selection experiments, with the goal to ascertain whether there is evidence for convergent/parallel evolution in the taxonomically distinct invertebrate species. This project is expected to advance our knowledge of adaptation to climate change by providing new insights into the impacts of temperature on a key life cycle stage and elucidate the genomic processes governing thermal adaptation in marine invertebrates.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.