Drivers of evolutionary changes and community dynamics in ancient Lake Ohrid across taxa: A synthesis of molecular, fossil and sediment record data

点击翻译按钮获取中文摘要

The Balkan Lake Ohrid is the most outstanding European ancient lake with an extraordinary species richness and a high degree of endemism in several groups of organisms. The processes generating this biodiversity are poorly understood. Preliminary genetic analyses of selected benthic animal groups in Lake Ohrid together with molecular clock estimations indicated that most of the endemic taxa evolved intralacustrine without major changes in diversification rates over time, pointing to an absence of catastrophic events during the geological history of the lake.This hypothesis has, among others, inspired the ICDP campaign (SCOPSCO) in Lake Ohrid. Starting in early April 2013, the SCOPSCO drilling operation became one of the most successful ICDP lake drilling campaigns ever conducted. Ca. 2100 m of sediment were sampled from Lake Ohrid until late May 2013. The sediments were recovered from four different sites with a total recovery of > 95%. First analyses indicated that the cores provide a continuous record of high-quality paleolimnological data and bear rich micro- and macrofossil assemblages. Moreover, preliminary analyses of diatom assemblages from core catcher samples showed significant shifts in diatom communities over time.Therefore, the main goal of the current proposal is to use a combination of molecular clock information derived from extant species as well as micro- and macrofossil data, on the one hand, and paleoenvironmental data from sediment cores (sedimentological, tephrostratigraphic, and paleo-habitat information), on the other, to infer the drivers of evolutionary changes and community turnovers in ancient Lake Ohrid across several taxa. The overall working hypothesis is that the absence of catastrophic events in Lake Ohrid and its high ecological resilience may have mitigated adverse evolutionary effects of environmental disturbances on lake taxa. Instead, these changes may have mainly triggered community turnovers.This proposal provides a novel approach in ancient lake studies. Building upon the synergies offered by the SCOPSCO drilling campaign, it combines temporarily explicit molecular, paleoenvironmental, paleontological, and evolutionary information from different animal and protist groups. Moreover, this information is primarily obtained from age-controlled sediment record data, which span the entire history of an ancient lake.