Collaborative Research: Exploring the Links among Climate, Ecology, and Evolution in Paleogene Marine Faunas of the U.S. Gulf Coastal Plain

最近对人类活动影响的气候变化的预测强调了了解生物体和生物群落如何应对长期和短期的扰动的重要性。化石记录中的数据可以为此类研究提供工具，为研究生态系统对人类仅用几年时间观察不到的旷日持久的气候变化的反应提供了可能性。PIS计划评估气候对美国墨西哥湾沿岸平原古近纪(约6500万年前至2500万年前)海洋软体动物动物群生态和进化的影响。他们的方法使他们能够将年平均温度和季节性的记录与多样性、群落组成和结构、形态(形状)和进化的变化结合起来。他们特别感兴趣的是了解气候变化的大小和方向与进化或生态变化的数量和性质之间是否存在相关性，包括是否存在容忍阈值，低于该阈值生态系统及其组成的分类群不会做出反应。PIS将从软体动物化石和鱼类耳石(耳石)的化学成分中产生古气候记录，而古生态模式将来自现有博物馆藏品、出版的文献和软体动物动物群的新现场采样。最后，他们将重建这两个主要软体动物群体--双壳贝类和甲壳腹足类--的进化关系和趋势，这两个群体是该地区和那个时代的特征，并将这些信息叠加在温度和生态记录上，以全面了解动物对气候变化的反应。他们的研究将大大有助于了解亚热带环境中的生物多样性如何应对不同类型和程度的气候变化。

Recent projections of anthropogenically-influenced climate change have emphasized the importance of understanding how organisms and biotic communities respond to perturbations on both the long and short term. Data from the fossil record can be instrumental in such studies, offering the potential to study the response of ecosystems to protracted climate change impossible to observe on human time scales of only a few years. PIs plan to evaluate the influence of climate on the ecology and evolution of marine mollusk faunas from the U.S. Gulf Coastal Plain during the Paleogene (~65-25 million years ago). Their approach allows them to integrate records of mean annual temperature and seasonality with shifts in diversity, community composition and structure, morphology (shape), and evolution. They are particularly interested in learning whether there is a correlation between the magnitude and direction of climate change and the amount and nature of evolutionary or ecological change, including whether or not there are thresholds of tolerance below which an ecosystem and its component taxa do not respond. PIs will generate the paleoclimate record from the chemistry of fossil mollusks and fish otoliths (ear stones), and paleoecological patterns will arise from a combination of existing museum collections, published literature, and new field sampling of mollusk faunas. Lastly, they will reconstruct evolutionary relationships and trends within two dominant mollusk groups - venericard bivalves and turritelline gastropods - that are characteristic of this region and time, and overlay this information on the temperature and ecologic records for a comprehensive picture of faunal response to climate change. Their research will contribute substantially to knowledge of how biodiversity in sub-tropical settings responds to climate change of varying types and magnitudes.