HR: 09:35h
AN: OS41E-06 [Abstracts]
TI: Interactive Ocean Observatories are Essential for Global Assessment of Plate-tectonically Modulated
Microbial Input to the Deep Ocean
AU: * Delaney, J
EM: jdelaney@u.washington.edu
AF: University of Washington, School of Oceanography
Box 357940, Seattle, WA 98195
United States
AU: Team*, K
EM: jdelaney@u.washington.edu
AF: University of Washington, School of Oceanography
Box 357940, Seattle, WA 98195
United States
AB:
A major new planetary-scale research thrust can only be addressed with interactive, next-generation ocean-observatory
capabilities. These new research opportunities arise from the possibility that input into the ocean of chemosynthetically
derived microbial biomass from below the seafloor rivals the biomass from primary photosynthetic productivity near the top of
the ocean. All three types of plate boundaries and many plate interiors vent microbe-bearing fluids into the deep ocean
continuously AND episodically. Unpredicted episodes increase nutrient output and venting volume by as much as a factor of 100
for weeks to months at a time (Lilley et al.,2003, Nature). Because of the highly non-linear nature of these fluxes,
quantification of such processes represents essential, but unconstrained, variables in equations for carbon budgets and
bio-flux in the deep ocean. Triggering events and their induced fluxes must be detected, located, responded to, and
quantified before their relative importance to the global-ocean system can be evaluated.
Addressing these issues requires an essential new capability in the ocean sciences. High-power and high-bandwidth cabled
systems will enable remote and long-term experimentation with processes via thousands of stationary and/or mobile sensor
platforms on, below, and above the seafloor. The Ocean Research Interactive Observatory Networks (ORION) program is currently
working with NEPTUNE Canada to produce a plate-tectonic-scale, regional cabled ocean observatory (RCO), an ideal platform
for adaptive surveillance and quantitative response to fluid-flux generating events at the margins and interior of the Juan
de Fuca (JdF) Plate.
The W. M. Keck Foundation is supporting a pre-NEPTUNE exploration of the linked processes involved in the
deformation-fluid/microbial flux concept. Thirteen seismometers (3 broadband, 10 short-period) and 45 fluid-movement/chemical
sensors are co-deployed on three different, but adjacent, plate boundaries at the northern end of the JdF Plate: the
Endeavour spreading segment, the Nootka transform fault, and the convergent margin at the toe of the Cascadia subduction
complex. All sensors are capable of measuring time-varying behavior for a year. A novel deep-sea remote sensor capable of
autonomous detection of microbial output at the seafloor will be added to the existing ensemble in 2005-6. These instrument
systems will be phased into NEPTUNE, scheduled to come on line in 2007-8. As of September 2004, we also have a live
satellite-mooring link from a seismometer and flow meter at a cold-seep site near the intersection of the Nootka transform
and the Cascadia prism.
The ultimate goal is to utilize the power of NEPTUNE-like installations to quantitatively assess the regional, and
eventually, the global, fluxes and biodiversity associated with this newly recognized tectonically-generated phenomenon of
subseafloor microbial productivity. Fully characterizing this planetary-scale process requires establishing a permanent
presence on the seafloor to continuously observe, document, and interact with co-varying processes driving fluid expulsion,
the chemical consequences, and the microbial responses. Similar phenomena may operate on other planets; we might even export
approaches learned on earth.
*The Keck Team includes more than 25 scientists and engineers from the Monterey Bay Aquarium Research Inst., Scripps Inst. of
Oceanography, Woods Hole Oceanographic Inst., Univ. of Victoria, Inst. of Ocean Sciences in Sidney, BC, and Univ. of
Washington.
DE: 4840 Microbiology
DE: 5475 Tectonics (8149)
DE: 4299 General or miscellaneous
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting