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

热带气旋（tc）是最具破坏性的自然灾害之一，造成巨大的死亡人数和经济损失。气候变化的影响在发展中国家，例如加勒比的许多小岛屿国家尤为强烈。目前，有关TC活动的仪器数据仅为最近~150年的数据，这些数据太短，无法了解TC活动的长期变化及其主要力量。因此，要改进未来对TC产状的预测，就需要从自然档案中获得更长的代理记录。到目前为止，沿海泻湖的冲积物最常用于识别过去的飓风登陆。然而，这些沉积物空间分布较小，保存潜力有限。相比之下，封闭盆地湖泊代表了大尺度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TCs的主要开发区（MDR）。盐湖地处半干旱区，降水季节差异大，蒸发量大，TC影响严重。由此产生的湖泊水位快速波动和盐度变化证明，该湖泊是开发与tc相关的极端降水的新型地球化学和生物代用物的关键地点。tc产生大量的降水，其氧同位素值（“量效应”）明显低于低纬度雷暴和“正常”降水。我们建议完善和改进稳定同位素（δ18O）重建古tc的方法。综合现代介形虫的生态和形态资料，结合水化学的季节变化，对钙质介形虫阀的δ18O和δ13C值进行校正。这是了解降水/蒸发变化和TCs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）及其δ18O和δ13C值的前提。这些发现将用于重建过去几个世纪的降水/蒸发和TC活动，这些活动基于化石介形虫物种组合和来自短沉积物岩心的介形虫δ18O和δ13C组成。

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.