ESH - COLLABORATIVE RESEARCH: Continental Ostracode Assemblages & Shell Geochemistry: Calibrating a Tool for Paleoclimatic and Paleohydrologic Reconstruction

小行星9725033 在全球气候变化领域，对从年际到千年时间尺度的高分辨率代用气候记录的研究越来越重要。 许多这些代用气候记录包括来自大陆沉积物（如湖泊、泉水和湿地）中的介形虫化石的同位素和微量元素地球化学数据。 介形虫（微观甲壳类）在海洋世界中发挥着与有孔虫相似的作用，通过其生态学、外壳地球化学和地理分布提供有关气候和水文循环相互作用性质的重要信息。 介形虫是大陆记录中最主要的钙质微体化石。 尽管越来越多的研究目前正在进行中，涉及大陆记录中的氧同位素和介形虫壳地球化学，有显着的知识基础的差距。 没有现有的研究提供，通过现场和实验室校准，同位素分馏和介形虫同位素组成之间的现代关系将仍然是最好的过去条件的定性指标。 依赖介形虫同位素信息的高分辨率大陆气候记录目前还没有量化的解释基础。 我们建议进行介形虫物种和壳化学的实地和实验室校准研究。 这项研究的重点是介形虫的现代分布及其同位素和微量元素签名，目的是将它们作为过去地球系统过程的代理指标。 基于实地的研究将校准介形虫物种分布和外壳化学（18 O，13 C，Mg/Ca，Sr/Ca），水化学（阳离子，阴离子，TIC，18 O，D，DIC的13 C）和气候数据。 这将包括对年度内和年度间变化的研究。 实验室研究将验证几种常见介形类的氧同位素和微量元素分馏行为作为水化学和温度的函数。 这项研究的结果将提供，第一次，介形虫同位素和微量元素组成作为古气候分析的可量化指标，通过现场和实验室校准的实验验证。 围绕季节性、水化学变化、生命影响和不同水文状况的基本问题将得到审查和评估。 因此，将填补古气候知识库中的一个根本空白。

9725033 Ito The study of high-resolution proxy climate records covering interannual through millennial time scales is growing importance in the field of global climate change. Many of these proxy climate records include isotopic and trace-element geochemical data derived from fossil ostracode shells in continental deposits, such as lakes, springs, and wetlands. Ostracodes (microscopic crustaceans) play a role similar to that of foraminifera in the marine world by providing vital information about the interactive nature of climate and the hydrologic cycle through their ecology, shell geochemistry, and biogeographical distribution. In fact, ostracodes are the primary calcareous microfossils in continental records. Despite the increasing amount of research presently underway involving oxygen isotopes and ostracode shell geochemistry in continental records, there is significant gap in the knowledge base. There are no existing studies available that provide, through both field and laboratory calibration, the modern relationship between isotope fractionation and ostracode isotopic composition will remain at best a qualitative indicator of past conditions. The high resolution continental climate records that rely on ostracode isotopic information have at present no quantified basis for interpretation. We propose to conduct both field and laboratory calibration studies of ostracode species and shell chemistry. This research focuses on modern distributions of ostracodes and their isotopic and trace-element signatures, with the purpose of developing them as proxy indicators for past Earth system processes. The field-based study will calibrate ostracode species distributions and shell chemistry ((18O, (13C, Mg/Ca, Sr/Ca), against hydrochemistry (cation, anion, TIC, (18O, (D, (13C of DIC) and climate data. This will include a study of intra-and inter-annual variation. The laboratory-based study will verify the oxygen-isotope and trace element fractionation behavior of several common speci es of ostracodes as a function of hydrochemistry and temperature. The results of this study will provide, for the first time, experimental verification through both field and laboratory calibration, of ostracode isotopic and trace-element composition as a quantifiable indicator for paleoclimate analysis . Basic issues revolving around seasonality, hydrochemical variability, vital effects, and different hydrologic regimes will have been examined and assessed. A fundamental gap in the paleoclimate knowledge base will thus be filled.