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Ocean Crust Processes and
Consequences for Life
Theme: Processes in the ocean crust, from
formation to subduction, and consequences for ocean-crust
exchange budgets and subseafloor life
Date: 2012 June 7-9
Host: Center for Marine Environmental Sciences (MARUM),
University of Bremen, Germany (UB)
Organizers: Heiner Villinger, Ulla Röhl,
and Wolfgang
Bach (all at UB)
Ocean crust is generated at mid-ocean ridges at a rate of
20 km3 per year,
but production rates vary strongly on regional scales, which
leads to pronounced differences in crustal architecture and
lithology. The ocean crust is in exchange with the oceans
throughout much of its lifetime. At any point in time, 1-2%
of the global volume of seawater resides within oceanic basement,
and it takes only a few 100,000s of years for the entire volume
of the oceans to circulate through the rocky seabed. The ocean
crust has been hypothesized to be the Earth's largest aquifer
and microbial habitat, yet the mechanisms and rates of interactions
between rocks, fluids, and microorganisms are still largely
unconstrained. Marine surveys and ocean drilling allow us
to examine crustal formation processes and plate-scale fluid
flow. In recent years, new strides have been made in addressing
the interrelations between seawater circulation, rock alteration
and microbial activity. Recent advances in subseafloor observatory
science (Juan de Fuca, South Chamorro, North Pond) have been
central in advancing our ability to gain critical new insights.
Likewise, tremendous progress has been achieved by using spectroscopic
and isotopic techniques for examining secondary mineral formation
and its relation to microbial activity.
The science conference part of the Bremen meeting provided
a forum for presenting and discussing the most recent results
in ocean crust processes and identifying the most pressing
challenges that lie ahead. Specific focus was on (1) crustal
heterogeneity and fluid flow, (2) ocean-crust interactions,
and (3) role of microbes in rock alteration.
Preliminary Program. The 3-day meeting had
equal time for a science conference and a training workshop.
Both parts were focused on recent developments in understanding
ocean crust formation and evolution, ocean-crust exchange,
and detection of subbasement life and microbe-rock interactions.
The conference portion provided a forum to present research
activities and findings to a broadly trained, but scientifically
focused audience. The training workshop served as a means
to further educate scientists and students. The aim was to
present key research techniques and methods commonly employed,
to discuss the pros and cons for specific applications, to
produce consensus recommendations, and to make available detailed
lab and field protocols. A visit to the IODP core repository
on campus showed first-hand the rock samples currently available
for study. In analogy to the ECORD
summer school on the Deep Biosphere in September 2008,
we provided a "virtual ship" experience in the facilities
of the IODP core repository in Bremen. Workshop participants
learned details of shipboard core recovery, sampling, and
other techniques pertinent to subseafloor biosphere expeditions.
Support for this meeting was also provided by the German
Research Foundation (DFG) and the German
IODP at BGR.
 
 
> See the 2012
workshop summary report
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