GEOGRAPHIC VARIATION IN ENVIRONMENTS AND EXTINCTION IN THE CARIBBEAN

加勒比地区环境和物种灭绝的地理变化杰里米·b·杰克逊加州大学圣地亚哥分校海洋研究所本奖项由2009年美国复苏和再投资法案（公法111-5）资助。了解重大灭绝事件的原因往往受到缺乏严格的环境和生物数据以及有限的地理覆盖范围的阻碍，这些数据可以帮助确定一个地区的事件在其他地区的反映程度。PI计划记录北加勒比地区（牙买加和多米尼加共和国）在过去1000万年的环境和进化变化模式，并将这些模式与从西南加勒比地区（或称SWC），包括巴拿马和哥斯达黎加获得的类似数据进行比较。由于巴拿马地峡的上升，SWC经历了季节性上升流和生产力的急剧下降，对苔藓虫和扇贝的详细进化研究有力地支持了生产力下降是导致这些群体高度灭绝和物种形成的假设。以前的分类学研究表明，灭绝程度相对较强，并且发生在大约同一时间的NC，但非常有限的可用数据表明，生产力可能没有相应的下降。这项研究将提供第一个详细的环境和生物数据来记录NC的变化序列。数据将与来自SWC的数据完全可比较，因为它们将使用相同的方法和标准收集和分析。结果将在广泛的区域内对生产率假设进行明确的检验。如果发达国家的生产率确实下降了，就没有必要寻找其他解释。但是，如果生产力没有下降，那么其他因素也一定在加勒比地区的灭绝中发挥了重要作用。可能的替代方案包括，由于区域变冷造成的海洋学变化，或在巴拿马门户关闭约100万年后，北半球冰川作用加剧，导致海平面上升和下降的速度加快。这个项目是非常可行的，因为在过去的25年里，广泛的地质和古生物学调查已经提供了必要的地层框架，开始把所有不同的故事拼凑在一起。

Geographic Variation in Environments and Extinction in the CaribbeanJeremy B. JacksonUniversity of California, San Diego, Scripts Institute of OceanographyThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Understanding the causes of major extinction events is often hampered by a lack of rigorous environmental and biological data and limited geographic coverage, which can help determine how closely events in one region are mirrored in others. The PI proposes to document patterns of environmental and evolutionary change in the Northern Caribbean (NC; Jamaica and the Dominican Republic) over the past ten million years and compare these patterns with similar data already obtained from the southwestern Caribbean (otherwise the SWC), including Panama and Costa Rica. The SWC experienced a dramatic decrease in seasonal upwelling and productivity due to the rise of the Panamanian Isthmus, and detailed evolutionary studies of bryozoans and scallops strongly support the hypothesis that decline in productivity was responsible for the very high extinction and speciation in these groups. Previous taxonomic studies suggest that extinction was comparably strong and occurred at about the same time in the NC, but the very limited data available suggest that there may not have been an equivalent drop in productivity. This study will provide the first detailed environmental and biological data to document the sequence of changes in the NC. Data will be entirely comparable with those from the SWC because they will be collected and analyzed using the same methods and criteria. Results will provide a definitive test of the productivity hypothesis over a broad region. If productivity did decline in the NC there will be little need to look for alternative explanations. But if productivity did not decline, then other factors must also have played an important role in Caribbean extinction. Possible alternatives include oceanographic changes due to regional cooling or increased rates of rise and fall of sea level associated with the intensification of Northern Hemisphere glaciation that occurred about one million years after the closure of the Panamanian Portal. The project is highly feasible because extensive geological and paleontological investigations over the past 25 years have provided the necessary stratigraphic framework to begin to fit all the different pieces of the story together.