Lake system response to Caribbean hurricane activity – a calibration study of ostracode (paleo-)biology and geochemistry (Lago Enriquillo, Dominican Republic)

热带气旋（Tropical Cyclones，TC）是造成巨大人员伤亡和经济损失的最具破坏性的自然灾害之一。技术合作的影响在发展中国家，如加勒比的许多小岛屿国家尤其严重。目前，有关TC活动的仪器数据仅在过去的150年，这是太短，以实现对TC活动及其主要力量的长期变化的理解。因此，改进TC事件的未来前景需要更长的代理记录从自然档案。到目前为止，海岸泻湖中的过洗沉积物最常用于识别过去的飓风登陆。然而，这些矿床的空间分布较小，保存潜力有限。与此相反，封闭流域湖泊代表了大规模降水事件的连续和高分辨率档案。多米尼加共和国的封闭盆地湖Lago Enriquillo位于TC的主要发展区（MDR）。盐湖位于半干旱地区，其特点是降水，强烈的蒸发和严重的TC影响强烈的季节性对比。由此产生的湖泊水位的快速波动和盐度的变化证明，该湖是一个关键的网站开发新的地球化学和生物代理TC相关的降水极端。TC产生大量降水，氧同位素值明显低于低纬度雷暴和“正常”降水（“量效应”）。我们建议完善和改进一个稳定的同位素（δ 18 O）的方法重建古TC。综合现代介形类的生态学和形态学资料，结合水化学的季节变化，标定钙质介形类阀的δ 18 O和δ 13 C值。这是了解降水/蒸发变化和TC影响如何反映在介形虫物种组合（物种组成、种群结构、形态变异性）及其δ 18 O和δ 13 C值中的先决条件。这些结果将用于重建降水/蒸发和TC活动在过去几个世纪的基础上，化石介形虫物种组合和介形虫δ 18 O和δ 13 C组成的短沉积物芯。

Tropical cyclones (TCs) are one of the most devastating natural disasters causing immense death tolls and monetary loses. TC impacts are particularly strong in developing countries such as many of the Small Island Countries in the Caribbean. Currently, instrumental data about TC-activities are available only for the last ~150 years which is too short to achieve an understanding of the long-term variability of TC activities and its main forces. Improved future prospections of TC occurrences require therefore longer proxy records from natural archives. So far, are overwash deposits in coastal lagoons most commonly utilized for the identification of past hurricane landfalls. However, these deposits have a small spatial distribution and a limited preservation potential. In contrast, closed-basin lakes represent continuous and high-resolution archives for large-scale precipitation events. The closed basin lake Lago Enriquillo in the Dominican Republic is situated in the Main Development Region (MDR) of TCs. The saline lake lies in a semi-arid region and is characterized by strong seasonal contrasts in precipitation, intense evaporation, and severe TC impacts. The resulting rapid lake level fluctuations and salinity changes prove that the lake is a key site for the development of novel geochemical and biological proxies for TC-related precipitation extremes. TCs produce large amounts of precipitation with distinctly lower oxygen isotope values (`amount effect´) than low-latitude thunderstorms and `normal´ precipitation. We propose to refine and improve a stable isotopes-based (δ18O) approach for the reconstruction of paleo-TCs. The integration of ecological and morphological data of modern ostracodes in combination with seasonal changes in hydrochemistry will be used to calibrate δ18O and δ13C values of calcareous ostracode valves. This is the prerequisite to understand how changes in precipitation/evaporation and influences of TCs are reflected in ostracode species assemblages (species composition, population structure, morphological variability) and their δ18O and δ13C values. These findings will be used to reconstruct precipitation/evaporation and TC activities during the past centuries based on fossil ostracode species assemblages and ostracode δ18O and δ13C compositions from short sediment cores.