Effects of Quaternary climate changes on morphological variability of aquatic invertebrates (ostracodes) within the ICDP project NamCore

ICDP NamCore 项目中第四纪气候变化对水生无脊椎动物（介形类）形态变异的影响

• 批准号: 537144079
• 负责人: Professorin Dr. Claudia Wrozyna
• 金额: --
• 依托单位: Division of Archaeological, Geographical and Environmental Sciences
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/537144079?language=en
• 关键词: Effects; Quaternary; climate; changes; morphological

The interplay between the evolution of the mountainous environments, monsoonal fluctuations and orbitally-forced climate changes resulted in the Tibetan Plateau (TP) being a montane biodiversity hotspot. Diversification of many modern lineages occurred between 2 Ma and 150 ka assumed to result from climate fluctuations and associated environmental changes. The exact origin and development of most ecosystems, especially lakes, on the TP is however largely unknown. Hence, relationships between monsoonal changes, local or regional environmental responses, and species distribution or diversity are not recognized so far. The main aim of the Nam Co Drilling project is to establish a continental record of detailed monsoon history on orbital to suborbital timescales back to 0.5-1 Ma on sediments of the Tibetan lake Nam Co (Co = lake). This long continuous record enables to investigate Quaternary biotic dynamics (species diversity and distribution, evolution) in relation to climate changes. Understanding the morphological variability of aquatic organisms can make a valuable contribution, as it depends on environmental and genetic influences. Ostracodes (Arthropoda, Crustacea) are ideal bioindicators to answer these questions since they are the only aquatic invertebrates in lacustrine settings forming skeletal carbonates which are easily and abundantly preserved, and can provide plenty of paleoenvironmental information due to their (species-specific) sensitivity for ecological changes. We suggest to investigate the long-term evolution of ostracode distribution and their morphological variability in Nam Co. This will reveal if the lake served as glacial refugium and was continuously populated by ostracodes, or if ostracodes became extinct when climate was cooling during glacials and repeatedly colonized the lake with, e.g., increasing temperatures. Characterization of morphology-environment relationships of modern populations will help to understand if morphological variability of the fossil ostracodes reflect environmental changes (e.g., temperature) or intra- and/or interspecific differentiation. Analyzes will be based on morphometric data of valve size, shape and ornamentation of L. sinensis-L. dorsotuberosa, the most dominant ostracode species in Nam Co. Identification of ecophenotypical characteristics will disclose how environmental changes impact ostracode valve morphology, and in particular which morphological traits are sensitive indicators for specific ecological parameters. This novel approach will therefore provide new insights on responses of the ostracodes to climate change and their effects on ostracode evolution and (paleo)ecology in general and in particular for the TP.

青藏高原山地环境的演变、季风波动和轨道驱动的气候变化之间的相互作用导致了青藏高原（TP）成为山地生物多样性热点。许多现代谱系的多样性发生在2 Ma和150 ka之间，这可能是气候波动和相关环境变化的结果。然而，TP上大多数生态系统，特别是湖泊的确切起源和发展在很大程度上是未知的。因此，季风变化，当地或区域的环境响应，物种分布或多样性之间的关系还没有认识到。纳木错钻探项目的主要目的是在西藏纳木错湖（Co =湖泊）的沉积物上建立一个关于轨道至亚轨道时间尺度的详细季风历史的大陆记录，时间可追溯到0.5-1 Ma。这种长期连续的记录使得能够研究与气候变化相关的第四纪生物动态（物种多样性和分布、进化）。了解水生生物的形态变异性可以作出宝贵的贡献，因为它取决于环境和遗传的影响。介形类（节肢动物门，甲壳纲）是湖泊环境中唯一能形成骨架碳酸盐的水生无脊椎动物，它们对生态变化具有敏感性，能提供丰富的古环境信息。我们建议调查纳木错介形虫分布及其形态变异的长期演变。这将揭示该湖是否作为冰川避难所并不断被介形虫种群所占据，或者介形虫是否在冰川期间气候变冷时灭绝并反复在该湖定居，例如，温度升高。现代种群形态-环境关系的表征将有助于理解化石介形类的形态变异是否反映了环境变化（例如，温度）或种内和/或种间分化。分析将基于瓣膜尺寸、形状和L.中华草属dorsotuberosa，最具优势的介形虫物种在纳木公司的生态表型特征的识别将揭示环境变化如何影响介形虫阀形态，特别是形态特征是敏感的指标，为特定的生态参数。因此，这种新的方法将提供新的见解介形虫对气候变化的反应和介形虫的进化和（古）生态学的一般，特别是TP的影响。