EGU General Assembly 2008

European Geosciences Union General Assembly, Vienna, Austria, 13-18 April 2008
http://meetings.copernicus.org/egu2008
Deadline Abstract Submission: 14 January 2008.

InterRidge-related sessions:
BG6.04: Session co-sponsored by InterRidge: Biogeochemical interactions in chemosynthetic deep-sea ecosystems: methods, tools and strategies
GM6.2: Session co-sponsored by InterRidge: Seafloor expression of tectonic and geomorphic processes
GD6: Structure and dynamics of mid-ocean ridges
GD7: Tracing hydrothermal circulation at mid-ocean ridges using geochemistry, geophysics and modeling
OS22/BG6.6/GMPV37/MPRG16/TS11: From Mantle to Ocean: Energy, material and life cycles at mid ocean spreading axes

Session co-sponsored by InterRidge: BG6.04: Biogeochemical interactions in chemosynthetic deep-sea ecosystems: methods, tools and strategies
Conveners: N. Le Bris (IFREMER, France), C. R. German (WHOI, USA), W. Bach (RCOM, U. Bremen, Germany), S. Duperron (U. Paris 6, France).

The past decade has raised challenging issues about the nature of interactions linking the biotic and abiotic components of deep-sea hydrothermal environments and other chemosynthetic habitats (e.g.: methane seeps, massive organic inputs like whales skeletons, wood falls,..etc). Among these are: the diversity and relative importance of microbial metabolisms in carbon fixation and mineralization processes, the role of key invertebrate species on biogeochemical transformations and fluxes.
Answers to these questions are required to appreciate the response of chemosynthetic ecosystems to environmental disturbance and their potential influence on the global biosphere.
This session will focus on new insights to these questions, including inter-disciplinary studies of biogeochemical and geobiological systems and advanced technological developments for the exploration, observation, experimentation and monitoring at relevant scales on the seafloor.

Session co-sponsored by InterRidge: "Seafloor expression of tectonic and geomorphic processes" (GM6.2)
Conveners: J. Hillier, N. Mitchell, M. Maia & T. Mulder

Bathymetry records and preserves a wealth of information about tectonic (e.g. fault scarps), geomorphic (e.g. channel erosion & landsliding), volcanic and geodynamic processes. New bathymetry (e.g. multibeam), especially when combined with sub-seafloor measurement, provides an exciting opportunity to combine geomorphology & geophysics and to extend geomorphology offshore.

This interdisciplinary session aims to examine the causes and consequences of the underwater landscape. The goal is to stimulate interdisciplinary work by bringing together researchers who quantify and characterize the shapes that form the seafloor, seek to understand the sub-surface processes at work and their impacts, or use bathymetry as a model input. A range of scales from ocean-wide (e.g. lithospheric cooling) to abyssal hills at the scale of meters, and datasets from satellite-predicted to multibeam are anticipated.

We welcome any exciting submissions in the spirit of the session, even if your particular process or bathymetric expression has not been explicitly mentioned. Perhaps: Hot-spot ridge interaction; Submerged glacial geomorphology; Quantifying underwater volcanoes; What stops subduction earthquakes - seafloor features?

For more information about the session: http://www.cosis.net/members/meetings/programme/view.php?m_id=49&p_id=304

You will find the session listed as GM6.2 in the geomorphology programme, and co-listed under SSP Stratigraphy, Sedimentology and Palaeontology, TS Tectonics and Structural, and GD Geodynamics.

GD6: Structure and dynamics of mid-ocean ridges
Mid-ocean ridges represent a unique window on mantle processes. After several decades of efforts from the marine geosciences community, many aspects are still debated, including mantle circulation and melting, melt migration and cooling, lower crustal accretion, magmatic or amagmatic extension, evolution of oceanic core complexes, melt distribution and mantle outcropping at ultra-slow ridges, interaction of various scales of mantle convection near hotspots ...etc. The session with bring together scientists from a large variety of disciplines, to compare and review observables and models of the structure and dynamics of mid-ocean ridges and associated mantle sources and circulation.

GD7: Tracing hydrothermal circulation at mid-ocean ridges using geochemistry, geophysics and modeling
The circulation of seawater within the axial zones and flanks of mid-ocean ridges: (i) influences heat transport from the lithosphere to the hydrosphere; (ii) modifies the bulk and isotopic chemical composition of the oceanic crust and its physical properties (magnetism, porosity, density and seismic velocity) via fluid-rock interaction and the formation of secondary minerals; and (iii) alters the chemistry of seawater through the expulsion of high to low temperature hydrothermal fluids at various depths. This session will bring together geophysicists, geochemists, mineralogists and modelers interested in the complexities of oceanic hydrothermal circulation. Within this broad remit, papers that aim to improve understanding of seawater circulation pathways through the oceanic crust and the role of hydrothermal cycling in heat, chemical and material fluxes between the lithosphere and the hydrosphere are particularly welcome.

OS22/BG6.6/GMPV37/MPRG16/TS11: From Mantle to Ocean: Energy, material and life cycles at mid ocean spreading axes
The session will encompass 6 cross-disciplinary (geology, biology, biogeochemistry, oceanography) questions:
-- How does the energy and mass transfer from the mantle into the ocean take place?
-- What are the time scales on which processes at spreading axes occur?
-- What factors govern where tectonic, magmatic, hydrothermal and biological processes occur on spreading axes?
--What factors control the form and extent of hydrothermal circulation systems in the sub-surface?
-- How do biological and hydrothermal processes interact?
-- How do ridge morphology and ocean currents control the dispersal of chemical and biological signals of hydrothermal activity along the ridge?