Terrestrial ecosystem response to climate variability during MIS 12-11 and MIS 19 in SE Europe based on high-resolution pollen analysis of Lake Ohrid ICDP core sediments.

详细了解第四纪极端冰期和间冰期的陆地生态系统和气候演变。该项目旨在为东南欧的海洋同位素阶段（MIS）12-11和（作为本后续提案中的一个新元素）19 c生成新的陆地花粉记录。通过对2013年通过ICDP钻探回收的奥赫里德湖（西南部巴尔干半岛的半岛）岩心材料进行高分辨率孢粉学研究，实现了项目目标。在项目的头两年，工作包（1）和（2）产生了（i）一个百年规模的MIS 11（~450年）花粉计数高的孢粉学记录（>500粒），孢子和藻类，以及基于花粉的温度和降水重建;（ii）欧洲第一个百年尺度（~400-800年）的MIS 12孢粉学记录。将孢粉学数据与奥赫里德湖科学小组内合作伙伴产生的沉积学和地球化学信息相结合，并与区域代用记录进行比较，有助于改善目前对东南欧及其他地区MIS 12-11期间陆地生态系统和气候演变的理解。迄今为止（即，经过23个项目月的研究，我们最重要的发现包括以下证据：（i）在完整的间冰期条件下，约405 ka时发生了一次强烈的冷却事件，这表明南欧千年尺度气候变率的开始发生在最温暖的子阶段MIS 11 c结束前约7 kyrs，并且早于海洋区域;（ii）在MIS 12期间，嗜热树木的短暂扩张，表明陆地生态系统对完整冰川条件下的Dansgaard-Oeschger（D-O）变暖事件的敏感反应;在MIS 12和MIS 11期间，奥赫里德湖流域存在稀有树木类群，支持该地区作为更新世树木避难所的观点。第三个项目年将致力于工作包（3），这将产生（i）MIS 12花粉记录的时间分辨率提高，从而能够更好地限制所检测到的D-O类事件的时间、克里思和性质;（ii）作为原建议的附加值，为MIS 19 c提供新的百年花粉记录，间冰期也被认为是一个密切的轨道模拟全新世与MIS 11一起;及（iii）项目结果的整体综合。具体而言，MIS 19 c新增加的组件将首次允许根据来自同一地点的三个间冰期（MIS 1，11 c和19 c）的高分辨率花粉记录，限制欧洲陆地生态系统对低偏心率强迫的响应。在相同的地理边界条件下）。总之，该项目将提供新的见解短期气候和环境变化的性质在东地中海地区的关键时期的第四纪。

To gain detailed insight into the terrestrial ecosystem and climate evolution under extreme glacial and interglacial intervals of the Quaternary. the project aims to generate new terrestrial pollen records for Marine Isotope Stages (MIS) 12–11 and (as a new element within this follow-up proposal) 19c in SE Europe. The project goals are achieved via high-resolution palynological study of core material from Lake Ohrid (SW Balkan Peninsula) that has been recovered through ICDP drilling in 2013. During the first two project years, Work Packages (1) and (2) have yielded (i) a centennial-scale (~450 years) palynological record for MIS 11 with high counting sums for pollen (>500 grains), spores and algae, as well as pollen-based temperature and precipitation reconstructions; and (ii) the first centennial-scale (~400–800 years) palynological record for MIS 12 in Europe. The integration of the palynological data with sedimentological and geochemical information generated by collaboration partners within the Lake Ohrid science party, and comparison with regional proxy records has helped to refine the current understanding of terrestrial ecosystem and climate evolution during MIS 12–11 in SE Europe and beyond. To date (i.e., after 23 project months), our most important findings comprise evidence for (i) a strong cooling event at ~405 ka during full interglacial conditions, suggesting that the onset of millennial-scale climate variability in Southern Europe occurred ~7 kyrs before the end of the warmest sub-stage MIS 11c and earlier than in the marine realm; (ii) a transient expansion of thermophilous trees during MIS 12, suggesting a sensitive response of terrestrial ecosystems to Dansgaard-Oeschger (D-O)-like warming events during full glacial conditions; (iii) the presence of rare tree taxa in the Lake Ohrid catchment both during MIS 12 and 11, supporting the notion that the area acted as a Pleistocene tree refugium. The third project year will be dedicated to Work Package (3), which will yield (i) an increased temporal resolution for the MIS 12 pollen record, allowing to better constrain the timing, tempo and nature of the detected D-O-like events; (ii) as an added value to the original proposal, a new centennial-scale pollen record for MIS 19c, an interglacial also considered a close orbital analogue for the Holocene alongside with MIS 11; and (iii) an overall synthesis of the project results. Specifically, the newly added component of MIS 19c will allow for the first time to constrain terrestrial ecosystem response to low eccentricity forcing in Europe based on high-resolution pollen records from three interglacials (MIS 1, 11c and 19c) from the same site (i.e., under identical geographical boundary conditions). In summary, the project will provide new insights into the nature of short-term climate and environmental change in the Eastern Mediterranean region during critical periods of the Quaternary.