Predicting the effects of ocean warming on larval dispersal by measuring adaptive potential of corals

在无根的海洋生物中，通过洋流散布幼虫是一种常见的策略，因此空间不连续的种群保持着共享的基因库。长寿的造礁珊瑚采用这种策略，将它们的浅水种群连接在一片荒凉的开阔海洋上。预计海水温度升高会加快幼虫的发育，因此平均扩散距离预计会缩短。与此同时，目前受年最低海水温度限制的物种可能会在未来几年向极地扩展它们的活动范围。该项目的目标是测量海水高温和低温对生命早期阶段的影响，并最终预测全球变暖导致的连通性模式的变化。预计物种内的个体和种群对不断变化的环境条件作出反应的能力不同。采用基因表达实验和种群基因组学相结合的方法，对造礁珊瑚（Acropora palmata）个体和种群间的适应性状变异进行了研究。从先前确定的两个加勒比棕榈纵蝽种群（佛罗里达和波多黎各）的控制杂交中获得的无共生体幼虫将暴露在一系列海水温度下，并记录其发育模式。幼虫池将通过下一代测序技术开发的40,000个探针微阵列进行查询。据推测，这两个种群的幼虫对海面温度的升高表现出相似的反应，但佛罗里达的幼虫更能在寒冷的冲击中生存。因此，微阵列数据将产生珊瑚温度适应的候选基因。这些数据将首次提供珊瑚全基因组适应性性状变异的估计，这些变异可以被纳入实时扩散模型，以预测全球变暖导致的连通性模式的变化。这项研究将通过为非模式物种开发新的基因组工具，首次提供珊瑚适应能力的广泛估计。这项研究将侧重于温度对造礁珊瑚扩散的影响，这是一个与全球变暖和珊瑚对变暖温度的敏感性特别相关的主题。棕榈Acropora palmata特别值得关注，因为它是目前被美国濒危物种法案列为受威胁的两种珊瑚之一。通过识别物种范围内的选择特征，保护工作可以根据适应性相似性优先考虑恢复材料的源种群。这里产生的转录组数据对更广泛的生物群落和整个社会都是无价的。这项研究包括教育和培训公众和公共机构的外联任务。自2005年以来，SECORE（有性珊瑚繁殖）组织举办了一系列研讨会，通过这些研讨会，该项目将帮助建立一个由公共水族馆和研究机构组成的国际合作网络，以建立珊瑚非原生境和野外种群的繁殖计划。研究生和本科生都是这个项目的组成部分，他们将接受实地和实验室工作以及讲座课程的培训。

Dispersal of larvae via ocean currents is a common strategy among sessile marine organisms and so spatially discontinuous populations maintain a shared gene pool. Long-lived reef building corals employ such strategies to connect their shallow-water populations across stretches of inhospitable open-ocean. Increasing seawater temperatures are predicted to quicken larval development so that average dispersal distances are expected to decrease. At the same time, species currently limited by minimum annual seawater temperatures may extend their ranges pole ward in the coming years. The objectives of this project are to measure the effect of high and low seawater temperatures on early life stages and ultimately predict changes in connectivity patterns as a result of global warming. It is expected that individuals and populations within species differ in their abilities to respond to changing environmental conditions. Adaptive trait variation among individuals and populations in the reef-building coral Acropora palmata will be measured by a combination of gene expression experiments and population genomics. Symbiont-free larvae obtained from controlled crosses from each of the two previously identified Caribbean A. palmata populations (Florida and Puerto Rico) will be exposed to a range of seawater temperatures and their development patterns documented. The larval pools will be interrogated by a 40,000 probe microarray developed with next generation sequencing. It is hypothesized that larvae from both populations show a similar response to increased sea-surface temperatures but that Florida larvae are better able to survive cold shocks. The microarray data will thus yield candidate genes for temperature adaptation in corals. These data will for the first time provide estimates of genome-wide adaptive trait variance in corals that can be incorporated into real-time dispersal models to predict changes in connectivity patterns as a result of global warming.This study will provide the first range wide estimates of adaptation in a coral by developing novel genomic tools for a non-model species. This research will focus on the effects of temperature on dispersal of a reef-building coral, a topic particularly relevant in light of global warming and the sensitivity of corals to warming temperatures. Acropora palmata is particularly worthy of attention because it is one of two coral species currently listed as threatened under the US Endangered Species Act. By identifying signatures of selection over the range of the species, conservation efforts can prioritize source populations for restoration material based on adaptive similarity. The transcriptome data generated here will be invaluable to the wider biological community and benefit society at large. This study includes outreach missions to educate and train the public and public institutions. Through continuing a series of workshops held since 2005 by SECORE (SExual COral REproduction), the proposed project will help build a cooperative international network of public aquariums and research institutions to establish coral breeding programs for ex situ and field populations of A. palmata. Graduate and undergraduate students are in integral part of this project and will receive training in field and laboratory work and lecture courses.