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Theme 3: Geosphere-biosphere-interactions

(Jörn Peckmann, Joachim Reitner, Kai-Uwe Hinrichs)

Session 3.1: Stable isotope proxies in space and time: Processes, preservation and potential

Michael Böttcher (IO-Warnemünde), Dorothee Hippler (Graz University of Technology, AT), Patrick Meister (Wien University, AT)

Keywords: Light and heavy stable isotopes, proxy calibration, mineral formation, diagenesis and water-solid-interactions

Light and heavy stable isotope signatures in sediments act as highly useful proxies storing crucial information for the reconstruction of (palaeo-) environments on regional and global scales, and even the development of life on Earth and other planets. The development of isotope signals is related to element sources, the processes and pathways of mineral formation as part of the biogeochemical element cycles. For a proper application careful calibrations of these proxies are required from field and experiment samples and the mechanisms impacting signal formation must be understood. Sedimentary biogenic and abiogenic archives span the whole time range from the Precambrian until today. Post-depositional alteration (e.g., mineral recrystallization; sulfurization of organic matter; selective mineralization of organic compounds) may further modify primary signals thereby (partly) destroying the original information, but providing new evidence for (e.g.) water-solid interactions during (microbially-catalyzed) diagenetic processes.
The significance of some of these sedimentary archives, as proxy for their ambient fluids and sometimes even the composition of the atmosphere, is often obtained from time-resolved records. Whereas mass-dependent effects in the systems of light stable isotopes (e.g. H, C, O, N, S) have received much attention since the pioneering studies in 1947 (although still not fully understood), more recently also metal isotope signatures, non-mass dependent effects and isotope clumping are expanding the stable isotope tool box.
Here we invite contributions involving field, experimental and theoretical studies that contribute to a better understanding of mechanisms responsible for the (trans-) formation of sedimentary stable isotope signatures from the cellular to the global scale.


Session 3.2: Going deep: Tracking life processes through time and space

Joachim Reitner, Jan-Peter Duda, Christine Heim (all: University of Göttingen)

Keywords: Geobiology, paleontology, astrobiology, early life, deep time, crustal deep biosphere, habitability, extraterrestrial life

Ever since life arose on Earth, it has fundamentally impacted environments on local and global scales. In fact, over the last few decades there has been a growing appreciation of the inherent linkage between geological and biological processes. It is now clear that understanding Earth - and possibly worlds beyond - requires understanding life and vice versa. However, our knowledge about life processes through time and space is still limited, and the extent of habitable environments still poorly constrained. These problems are due to the enormous diversity of metabolisms, the huge complexity of biological communities, and the great variety of potential habitats. A further drawback is the unambiguous identification and interpretation of biological fingerprints. Aiming at tackling these challenges, we invite contributions exploring biological communities and their habitats through time and space. We particularly welcome progressive and provocative studies that combine classic approaches with innovative state-of-the-art techniques for tracking life processes on Earth and, possibly, beyond.


Session 3.3: Geomicrobiology - from understanding processes in ancient and modern environments to industrial applications

Andreas Kappler (University of Tübingen), Jörn Peckmann (University of Hamburg)

For this session we invite contributions related to geomicrobiological processes in modern and ancient environments as well as studies on the use of microorganisms for industrial applications. This includes microbial contributions to biogeochemical processes, mineral transformation and rock formation on early Earth. We also encourage presentations of field-based, experimental and theoretical contributions on geomicrobiological processes in modern soils, sediments, rocks and the subsurface. Finally, we would like to provide a platform to discuss the impact of geomicrobiological processes in natural and engineered environments on a range of scales, from reaction pathways and single cells to global biogeochemical cycles including applied studies for example on biomining or other industrial applications.


Session 3.4: Coastal depositional environments & processes

Thomas Mann (ZMT, Bremen), Tim Jennerjahn (ZMT, Bremen), Nils Moosdorf (ZMT, Bremen), Alessio Rovere (MARUM, Bremen)

Through all climatic zones, coastal regions are areas of permanent transition where physical and biogeochemical processes interact. With the shoreline as the actual interface between the land and the sea, coastal regions are certainly among the most rapidly changing systems on the Earth´s surface. This is on the one hand related to natural co-adjustments between process and form – and on the other hand a result of the increasing impact of humans.
Coastal zones are subject to engineering works changing the oceanographic boundary controls. Coasts receive considerable amounts of particulate and dissolved substances through riverine and groundwater freshwater input. Both provide marine ecosystems with important nutrients. However, and particularly with increasing human influence on land-derived substances, these processes can also threaten coastal ecosystems. Additionally, environmental changes such as ocean acidification and sea-level rise, as predicted for the coming decades, are likely to have a drastic impact on both, the physical coastal evolution as well as ecosystem functioning. As much of the world´s population lives close to the shoreline and, especially in the tropics, is often dependent on coastal ecosystem services, understanding the physical and biogeochemical response of coastal systems to past, present and future environmental changes is of utmost importance.
This session invites contributions covering all aspects of Coastal Hydrology, Geomorphology, Sedimentology and Biogeochemistry to aid our understanding of coastal depositional environments & processes. We seek to combine studies dealing with present-day settings as well as with reconstructions on time scales relevant to the human dimension. This includes investigations on the rates and causes of coastal changes at different temporal and spatial scales; reconstructions of past ecosystem response to environmental changes; effects of terrestrial influence on coastal systems, and the applicability of bio-indicators in different coastal ecosystems. We welcome studies that use observational, experimental, theoretical and interdisciplinary methodological approaches in order to distinguish between natural and anthropogenic causes of geomorphological and biogeochemical coastal change from the recent-past to the present.