Projet 596 - Climate Change and Biodiversity Patterns in the Mid-Paleozoic
The Mid-Paleozoic conforms to a time interval of dynamic long-term climate change, which was accompanied by substantial variations in biodiversity. Within the framework of this project we intend to increase and refine the documentation of biodiversity mainly in tropical realms during Early Devonian-Early Carboniferous times and identify links to climate change. Groups distinctive for different ecosystems, especially indicating terrestrial, neritic and pelagic marine environments, are land plants, phytoplankton, foraminifers, sponges, corals, arthropods, cephalopods, echinoderms, brachiopods, bryozoans, conodonts and fishes. In addition to general diversity patterns of different fossil groups, we will study three distinctive intervals in detail, which should document biodiversity and the intensity of evolutionary-pressure during (1) greenhouse (Givetian), (2) beginning climate change (Early-Middle Frasnian; e.g. punctata-Zone) and (3) icehouse conditions (Late Famennian–Tournaisian).
The rapid rise of land plants during the Middle Devonian was coupled with strongly decreasing atmospheric CO2 values from 4000 ppm to nearly present day values of about 350 ppm during the latest Devonian (compare Royer, 2006). This dynamic climate shift was followed by a complete reorganisation of ecosystems with tremendous consequences for marine communities at global scales. The interaction between developments on land, such as the formation of top-soil and its influence on the geochemical composition of marine environments are considered as important factor probably responsible for evolutionary trends in biodiversity. Therefore geochemical analysis of carbon, oxygen and strontium isotopes as well as the total organic content and sulfur of sedimentary rocks will be measured to reconstruct prevailing paleoenvironmental conditions. Additionally, geophysical data related to the magnetic susceptibility and the natural gamma radiation of sediments (in cooperation with IGCP 580) will be used as auxiliary methods for high resolution correlation of biostratigraphic well-documented units belonging to different bathymetric sequences within the tropical belt (Laurussia, Siberia, peri-Gondwana and N-Gondwana).
Results of this project should show whether climate change (e.g. interaction of CO2 and temperature) from greenhouse conditions during the Early-Middle Devonian to icehouse conditions during the Late Devonian-Early Carboniferous represents a major trigger for variations in biodiversity or if a combination of multiple factors is responsible for such changes.
Related to this study, a network of taxonomic workers will be established, which will help to update the systematics of Mid-Paleozoic terrestrial and marine organisms. These datasets will be made available to the public by using existing e-infrastructures such as the Paleobiology Database.
The benefit of this project regards scientific as well as social purposes. On the one hand results of the project might help to understand our present day situation and climate change in future by documentation of Mid-Paleozoic climate change and its effect on biodiversity. On the other hand, our novel combination of global earth system sciences and analytical paleobiology will help to integrate and educate young researchers responsible for the preservation of knowledge in future.
The proposed project makes a strong case for meeting the key criteria of IGCP: With three female project co-leader, many enthusiastic young scientists involved for research and training, and strong involvement of researchers from low developed countries (Russia, Thailand, Mongolia, Vietnam etc.), combined with a strong team of experienced research leaders on topic and region.