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Collaborative Research: Interglacial climate in Bermuda and beyond

合作研究：百慕大及其他地区的间冰期气候

基本信息

批准号：
1903237
负责人：
Sierra Petersen
金额：
$ 39.48万
依托单位：
Regents of the University of Michigan - Ann Arbor
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1903237&HistoricalAwards=false
关键词：
Collaborative Research Interglacial climate Bermuda

项目摘要

This project will assess the variability of ocean surface temperatures along the U.S. East Coast and in the Caribbean for a key past warm climate period, the Last Interglacial (MIS 5e, 130-116,000 years ago). The Last Interglacial period is often thought to be one of the best past analogs to study in relation to expected near-future climate change because global sea surface temperatures were slightly warmer than today, and sea level was several meters higher. Additionally, because the Last Interglacial was geologically recent, well-preserved fossils that record paleoclimate information in the chemistry of their shells are relatively abundant. Previous efforts to map past sea surface temperatures across the North Atlantic have been undertaken, but a glaring data gap exists along the U.S. East Coast and as far as 1000 km out to sea. More than 40 million people currently live along the U.S. Atlantic seaboard and in the Caribbean. In addition to the direct impacts of a warmer climate, warming coastal sea temperatures can also strengthen Atlantic hurricanes, increasing damage to coastal infrastructure. Thus, it is of societal importance that we improve our knowledge of the potential for coastal water temperatures to increase in a warming world. By studying the Last Interglacial time interval, regional temperature estimates can be obtained from fossils that will help reveal how much ocean temperatures could potentially warm in this highly-populated region. This project will produce new high resolution paleotemperature reconstructions from well-preserved fossil mollusks found in transgressive beach deposits and raised paleo-reef deposits that are dated to the Last Interglacial. The research team will conduct field work to gather fossil mollusk samples from sedimentary sequences of interglacial age in Bermuda, the Bahamas, and multiple localities along the US East Coast from the Florida Keys up to the Massachusetts Cape. Collected shells will be analyzed for their stable and clumped isotopic compositions to determine past temperature and the oxygen isotopic composition of seawater (d18Osw; related to salinity) at each locality. The clumped isotope paleothermometer represents an advancement over traditional methods and will produce more robust paleoclimate information without the need to assume past d18Osw values. The resulting basin-scale map of interglacial paleotemperature and d18Osw will be useful for inter-proxy, model-proxy, and paleo-modern-future comparisons and to look for evidence of mid-interglacial meltwater events. Larger shells will be sampled at sub-annual resolution to determine paleo-seasonality in temperature at different latitudes. This research should thus not only yield a spatial pattern of interglacial hydrography in the study region but will be the first to do so at the seasonal time scale. In Bermuda, interglacial deposits from multiple past interglacials will also be sampled to compare stronger and weaker interglacial periods. As part of this project, one or more graduate students and multiple undergraduates will receive training in advanced geochemical techniques, field work and data analysis. Engaging activities relating to fossil and modern seashells will be brought to elementary and middle school students through science events in Michigan. The project will support two early career scientists who will receive mentoring from a senior co-principal investigator.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.

该项目将评估海洋表面温度的变化沿着美国东海岸和加勒比地区的一个关键的过去温暖的气候时期，最后一个间冰期（MIS 5e，130- 116000年前）。最后一个间冰期通常被认为是与预期的近期气候变化有关的最佳过去模拟研究之一，因为全球海面温度比今天略高，海平面高出数米。此外，由于末次间冰期在地质学上是最近的，保存完好的化石记录了它们外壳化学中的古气候信息。以前的工作是绘制北大西洋过去的海面温度，但在沿着美国东海岸和远达1000公里的海上存在明显的数据缺口。目前有4000多万人居住在沿着美国大西洋沿岸和加勒比海地区。除了气候变暖的直接影响外，沿海海水温度变暖也会加强大西洋飓风，增加对沿海基础设施的破坏。因此，它是社会的重要性，我们提高我们的知识的潜力，沿海水温增加在一个变暖的世界。通过研究末次间冰期的时间间隔，可以从化石中获得区域温度估计，这将有助于揭示在这个人口稠密的地区，海洋温度可能会变暖多少。该项目将利用在海侵海滩沉积物和上升的古礁沉积物中发现的保存完好的软体动物化石重建新的高分辨率古温度，这些化石可追溯到末次间冰期。该研究小组将进行实地工作，从百慕大、巴哈马和沿着美国东海岸从佛罗里达群岛到马萨诸塞州海角的多个地点收集间冰期沉积序列中的软体动物化石样本。将分析收集到的贝壳的稳定和聚集的同位素组成，以确定每个地点过去的温度和海水的氧同位素组成（d18 Osw;与盐度有关）。聚集同位素古温度计代表了传统方法的进步，将产生更强大的古气候信息，而不需要假设过去的d18 Osw值。由此产生的盆地规模的地图间冰期古温度和d18 OSW将是有用的代理，模型代理，和古现代未来的比较，并寻找证据的中期间冰期融水事件。将以次年度分辨率对较大的贝壳进行取样，以确定不同纬度温度的古季节性。因此，这项研究不仅应产生一个空间格局的间冰期水文在研究区域，但将是第一个这样做的季节性时间尺度。在百慕大，还将对过去多次间冰期的间冰期沉积物进行取样，以比较较强和较弱的间冰期。作为该项目的一部分，一名或多名研究生和多名本科生将接受高级地球化学技术、野外工作和数据分析方面的培训。与化石和现代贝壳有关的参与活动将通过密歇根州的科学活动带给中小学生。该项目将支持两名早期职业科学家，他们将接受高级联合首席研究员的指导。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。