Barriers to cross-shelf coral connectivity in the Florida Keys

佛罗里达群岛的珊瑚礁正在严重减少，这是近海珊瑚礁区域最突出的地方，而许多近岸珊瑚礁仍保持着很高的珊瑚礁覆盖率。那么，为什么从幸存下来的近岸斑块产生的珊瑚幼虫不会重新定居在近海珊瑚礁呢？研究人员推测，由于不同环境条件的遗传专门化，这些跨陆架迁徙动物不能在新的栖息地生存，具体到它们的起源珊瑚礁。该项目将分析珊瑚种群的遗传多样性，以量化这一障碍在三种常见珊瑚物种中的严重程度。这将是第一项评估珊瑚在海景中扩散的生态障碍强度的研究，这将填补一个重要的知识空白，目前这一空白阻碍了对佛罗里达州珊瑚礁威胁的知情评估，并开发出准确的模型来预测其未来。该项目包括各种更广泛的影响活动。公众宣传：该项目很好地提高了公众对生物多样性持续丧失的认识。调查人员定期在奥斯汀的不同场所进行公开演讲，如星光下的科学、酒吧中的科学和Nerd Nite。在项目进展之后，将在德克萨斯大学公共宣传网页KNOW和每日德克萨斯人上发布新闻稿、材料。K-12外展：来自克罗基特高中的两名实习生将参与这项研究。研究生教育：该项目将成为一名全日制研究生的主要博士生主题。本科教育：首席调查员定期雇用本科生。在这个项目中，他们将参与实地实验和样品处理，并在随后分配单独的子项目。促进快速数据共享：所有测序数据在公布前将无条件提供使用。具体地说，研究人员将迅速分享新的珊瑚基因组数据，以及珊瑚种群基因组变异的数据。该项目由四个部分组成，每个部分都旨在展示近岸和近海珊瑚礁的差异选择行动，并对其人口影响进行量化估计。(1)寻找近岸和近海栖息地之间正在进行的选择的基因组特征。研究小组将对代表不同生活史的三种珊瑚物种进行全基因组基因分型，并沿着佛罗里达珊瑚礁区域复制近岸和离岸种群的比较。(2)通过比较幼体和成体的近岸-离岸分化程度来确认选择的持续性作用。据推测，幼鱼经历局部选择的时间较短，因此在候选基因座上应该表现出较少的跨架分歧。(3)通过对基因分型幼虫的原位生长和存活进行量化，证明候选基因座上的基因与局部适合度之间的关联。这一部分和第二部分预计将提供针对跨货架移民的选择强度的量化估计。(4)通过模拟发散选择下的基因组进化并确认所提出的选择方案与观察到的基因组特征相一致来验证所获得的估计。

Coral reefs in the Florida Keys are in severe decline, which is the most prominent along the offshore reef tract while many nearshore reefs retain high coral cover. Why then coral larvae produced from surviving nearshore patches do not recolonize offshore reefs? The investigators hypothesize that such cross-shelf migrants do not survive in the new habitat due to genetic specialization for different environmental conditions, specific to their reef of origin. This project will analyze genetic diversity of coral populations to quantify the severity of this barrier in three common coral species. This will be the first study to assess the strength of ecological barriers to coral dispersal across the seascape, which will fill an important knowledge gap that currently precludes informed assessment of threats to Florida reefs and development of accurate models to forecast their future. The project includes a variety of broader impact activities. Public outreach: This project is very well poised to raise public awareness of ongoing biodiversity loss. The investigators regularly give public lectures at diverse Austin venues, such as Science Under the Stars, Science in the Pub, and Nerd Nite. The progress of the project will be followed by press releases, materials on the University of Texas public outreach web page Know and in The Daily Texan. K-12 outreach: Two interns from Crockett High School and will be involved in the research. Graduate education: The project will be the main PhD theme for one full-time graduate student. Undergraduate education: The primary investigator regularly employs undergraduates. In this project they will participate in field experiments and sample processing, and later assigned individual sub-projects. Promotion of rapid data sharing: All sequencing data will be made available for unconditional use prior to publication. Specifically, the investigators will rapidly share new coral genome data, as well as data on genome-wide variation in coral populations.The project consists of four parts, each of which is designed to demonstrate the action of divergent selection among nearshore and offshore reefs and to obtain quantitative estimate of its demographic impact. (1) To look for genomic signatures of ongoing selection between inshore and offshore habitats. The research team will perform genome-wide genotyping in three coral species representing alternative life histories and replicate the nearshore-offshore population comparison along the Florida Reef Tract. (2) To confirm continuous action of selection by comparing the extent of inshore-offshore divergence among juveniles and adults. Juveniles are presumed to have experienced local selection for shorter time and hence should show less cross-shelf divergence at the candidate loci. (3) To demonstrate association of genotypes at the candidate loci with local fitness by quantifying in situ growth and survival of genotyped juveniles. This part as well as part 2 is expected to provide quantitative estimates of the strength of selection against cross-shelf immigrants. (4) To verify the obtained estimates by simulating genome evolution under divergent selection and confirming that the proposed selection scenario is compatible with the observed genomic signatures.