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.

以详细了解第四纪极端冰期和间冰期下的陆地生态系统和气候演变。该项目旨在为欧洲东南部的海洋同位素阶段12-11和19c(作为后续建议的一个新内容)生成新的陆地花粉记录。通过对奥赫里德湖(巴尔干半岛西南部)的岩芯材料进行高分辨率孢粉研究，实现了项目目标，这些岩芯材料已于2013年通过ICDP钻探获得。在项目的头两年，工作包(1)和(2)产生了：(I)管理信息系统11的百年尺度(~450年)的孢粉记录，花粉(&gt；500粒)、孢子和藻类的高计数以及基于花粉的温度和降水重建；(Ii)欧洲管理信息系统12的第一个百年尺度(~400-800年)的孢粉学记录。将孢粉学数据与奥赫里德湖科学党内部合作伙伴提供的沉积学和地球化学信息相结合，并与区域替代记录进行比较，有助于完善目前对欧洲东南部和其他地区MIS12-11期间陆地生态系统和气候演变的理解。到目前为止(即23个项目月后)，我们最重要的发现包括以下证据：(I)在完全间冰期条件下，约405ka处发生了强烈的冷却事件，表明南欧千年尺度气候变率的开始出现在最温暖的亚阶段MIS11c结束前约7Kyr，并且早于海洋领域；(Ii)MIS12期间耐热树木的瞬时扩张，表明陆地生态系统对充分冰川条件下类似Dansgaard-Oeschger(D-O)的变暖事件做出了敏感的反应；(Iii)在管理信息系统第12和第11次会议期间，奥赫里德湖流域都出现了稀有树种，支持该地区作为更新世树木避难所的观点。第三个项目年将专门用于工作包(3)，这将产生：(1)提高管理信息系统12的花粉记录的时间分辨率，从而能够更好地限制探测到的类似D-O事件的时间、节奏和性质；(2)作为最初提议的附加价值，为管理信息系统19c和管理信息系统11提供一个新的百年尺度的花粉记录；(3)综合项目成果。具体地说，管理信息系统19c新增加的部分将首次允许根据同一地点(即在相同地理边界条件下)的三个间冰期(管理信息系统1、11c和19c)的高分辨率花粉记录，限制陆地生态系统对低偏心率强迫的反应。总之，该项目将对第四纪关键时期东地中海区域短期气候和环境变化的性质提供新的见解。

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.