S76: Marine biogeochemistry and Earth's atmosphere

Conveners:	D. Wallace	(dwallace@ifm-geomar.de)
	P. Swart	(pswart@rsmas.miami.edu)
	H. Herrmann	(hartmut.herrmann@tropos.de)

This session will present observational, experimental, and theoretical approaches to understand the role of biogeochemistry as a control on atmospheric chemistry. The carbon cycle in general, but in particular the carbon storage/release related to marine biomass, methane storage/release, and the role of the oceans as a control on CO₂ fluxes will be explored. A major goal of this session is to bring together a diverse group of researchers that will include those working on terrestrial controls (i.e. dust, silicate weathering, etc.) and those working on ocean controls, as well as bridging observational, experimental, and modelling approaches.

S77: Geochemical evidence for changing oceans

Conveners:	Simone Kasemann	(Simone.Kasemann@ed.ac.uk)
	D. Schmidt	(d.schmidt@bristol.ac.uk)
	D. Vance	(d.vance@bristol.ac.uk)
Keynote:	Ken Caldeira	(Carnegie Institution of Washington)

Important variations in ocean chemistry have been documented associated with past climate change. Thus the reconstruction of past ocean conditions is a powerful tool for assessing the likely potential impacts of future climate change. This session will concern both long-term changes and transient perturbations of the physics and chemistry of the ocean. We invite submission of papers that seek to reconstruct past ocean conditions during all time intervals in Earth history. We seek to encourage cross-disciplinary discussion between marine biogeochemists. Therefore, our goal is to gather together a wide range of researchers with interests in all aspects of past environments and ocean chemistry including (but not exclusive to) practical applications of trace element, isotope and biomarker proxies to paleoceanography as well as theoretical/modelling approaches.

S78: Multi-proxy investigations of the marine environment

Conveners:	A. Eisenhauer	(aeisenhauer@ifm-geomar.de)
	G. Camoin	(gcamoin@cerege.fr)
	M. Frank	(mfrank@ifm-geomar.de)
Keynote:	Harry Elderfield	(Cambridge, UK) Urey Medal 2007, EAG

Geochemical and isotopic analyses of various sediment components such as microorganisms, organic material, authigenic material, clay minerals, and the detrital fraction provide important information on past ocean environments, including ocean circulation, redox conditions and biological productivity. Some proxy data, however, yield conflicting information and it is the aim of this session to both identify and explore the reasons for these discrepancies. We especially encourage presentations on multi-proxy applications and records of the past marine environment, as well as contributions on proxy validation and new proxy development.

S79: Biogeochemistry in extreme marine environments

Conveners:	K. Wallmann	(kwallmann@ifm-geomar.de)
	P. Linke	(plinke@ifm-geomar.de)
	A. Boetius	(aboetius@mpi-bremen.de)
Keynote:	Katrina J. Edwards	(University of Southern California, Los Angeles, USA)

Extreme biogeochemical ecosystems, like the hydrothermal cells of the mid-ocean ridges and the cold seeps at subduction zones where microbial communities exist in tandem with minerals, water, dissolved molecules, and gases are environments which are well outside the ënormalí realm of life. The study of these geochemical extremes has provided important insights and substantial discoveries regarding the limits, origin, and evolution of life. Extreme environments serve as a setting for investigating relationships between biology and geochemistry in detail - enhancing our understanding of microbe/mineral interactions, effects of ecological stresses, and connections between members of microbial consortia. This symposium brings together an array of researchers investigating geochemical/biological processes in extreme environments ­ settings typified by extremes of pH, temperature, pressure, metal content, organic contaminants, UV stress, radiation, and desiccation.

S80: Biomineralization in the marine realm: Processes and signatures in natural and model systems

Conveners:	J. Erez	(erez@vms.huji.ac.il)
	M. Dietzel	(dietzel@egam.tu-graz.ac.at)
	C. Rollion-Bard	(rollion@crpg.cnrs-nancy.fr )
Keynote	Howard Spero	(Davis, CA)

Biominerals are abundant throughout the ancient rock record, as well as modern sediments, and water columns, and are major components of global biogeochemical cycles. Chemical and isotopic signatures within biominerals are chemical and physical indicators for the environments from which they formed; however, interpreting these signatures is difficult because the physiological environment of the organism may differ from extracellular conditions. Unravelling these vital effects requires an understanding of fundamental pathways and processes of biomineralization. Analysis of natural systems continues to yield valuable information about biomineralization processes. Complementary insights into how mineral formation occurs within living organisms can be gained by laboratory culturing and model systems that are investigated by experimental and theoretical means. With this approach, the physical basis of biomineralization may be elucidated and the superimposed effects of biological processes on environmental proxies may be quantified. We encourage contributions from field, laboratory, and theoretical studies related to this rapidly developing research area.

S81: Mechanisms of CO₂ storage in deep onshore and offshore geological formations

Conveners:	M. Kühn	(m.kuehn@geophysik.rwth-aachen.de)
	G. Rehder	(gregor.rehder@io-warnemuende.de)
	S. Benson	(smbenson@lbl.gov)
	A. Busch	(busch@lek.rwth-aachen.de)
Keynote:	Michael A. Celia	(Princeton, USA)

Concerns about global warming and rising concentrations of greenhouse gases in the atmosphere have led to worldwide interest in carbon dioxide (CO₂) sequestration, capture and storage (CCS). Various available storage options such as injection into deep geological formations, terrestrial aquifers, seawater and marine sediments have been proposed to reduce the amount of anthropogenic CO₂ released into the atmosphere. This session provides a forum for the presentation and discussion of latest research on CO₂ storage in terrestrial and marine environment such as seawater, marine sediments, deep saline aquifers, depleted oil or gas fields, or uneconomic coal seams. Both onshore and offshore systems will be addressed. Contributions are welcome that present fundamental concepts and case studies focusing on the various storage mechanisms, for example: experimental studies of geochemical water-rock interactions, computations ranging from basin scale to the scale of laboratory and micro scale measurements as well as natural analogue studies.

S82: Timescales and rates of climate change

Conveners:	G. Winckler	(Winckler@ldeo.columbia.edu)
	S. Mukhopadhyay	(sujoy@eps.harvard.edu)
	A. Immenhauser	(adrian.immenhauser@rub.de)
Keynotes:	Maureen Raymo	(Boston University)
	Martin Frank	(IFM GEOMAR, Kiel)

The study of climate change through earth history requires robust chronologies. This is of particular importance where global correlations of geological records of climate change are considered. Various elemental and isotopic tracers have been used as chronometers to constrain the timing of events and rates of climatic processes. A major goal of this symposium is to bring together a diverse group of researchers working on a wide range of isotope systems and time-scales, from millennia to the Palaeozoic. We invite contributions that present novel approaches to constrain time scales and rates of climatological processes or novel insights into paleoclimatological questions utilizing new or established techniques (such as U-series, constant flux proxies, cyclostratigraphy, etc.).