UW Oceanography Mid-Ocean Ridge Processes: Research Projects
The hot fluid discharged from hydrothermal vents on the seafloor rises as
a plume in the deep ocean. This project involves use of the submersible
ALVIN to characterize the time and space scales associated with
entrainment of local seawater into this rising plume and the accompanying
chemical
and biochemical reactions. Funded by the National Science Foundation.
Investigator Russ McDuff, Collaborators: NOAA PMEL: John Lupton, Richard Feely, Gary
Massoth; UC Santa Barbara: Libe Washburn
Flanges are overhanging ledges projecting from large constructional
sulfide edifices which trap ponds of buoyant high temperature fluid.
The flange environment represents a microcosm of a hyrothermal system,
one which can be well-instrumented to study the flow of energy into the
associated biological community. Funded by the National Science
Foundation. Investigators John Delaney, Russ McDuff, Marv Lilley
The Jason remotely operated vehicle is a new and flexible technology for
studying the seafloor. This initial science program had the goal of
evaluating the use of this new tool in a well studied area on the
Endeavour Segment of the Juan de Fuca Ridge. Funded by the Office of
Naval Research.
Some imagery from the program is
available on the DSL server at
WHOI, operators of the Jason ROV.
Investigators: John Delaney, J.-C. Sempere, Russ McDuff.
Spatial variability in vent fluid chemistry
has been interpreted by ourselves and others as a result of a complex
series of processes related to phase separation and segregation within
the oceanic crust. This program examines an alternative hypothesis,
that the spatial patterns seen are related to the mixing of fluids
associated with two adjacent, independent hydrothermal convection
cells. Funded by the National Science Foundation. Investigators: John
Delaney, Russ McDuff , Marv Lilley.
Collaborators: NOAA PMEL: Dave Butterfield, John Lupton. Project Web.
Studies over the
past decade suggest that the "quantum" event of ocean crustal
construction is a the injection of a dike. This perturbation, marked
by seismic activity, may change the intensity of existing hydrothermal
circulation or even initiate new activity. This project couples a
modelling study of these effects with continuing field work at the site
of a recent diking event, the CoAxial event of 1993. More information
is available on the
Coaxial Home Page maintained by NOAA's PMEL. Funded by
the National Science Foundation. Investigators: John Delaney, John
Baross, Russ McDuff, Marv Lilley, Will Wilcock.
Collaborators: University of Arizona: Denis Norton.
The very essence of a hydrothermal system is transfer of heat by a
convecting
fluid. Despite this central role played by heat transfer, we have a
woefully poor
knowledge of the flux of heat from seafloor hydrothermal systems and its
variation
through time. This lack of knowledge is not from a lack of trying.
Many different
investigators have made estimates of the flux of heat from seafloor
hydrothermal
systems. The Endeavour Segment of the Juan de Fuca Ridge is perhaps the
best-
studied example.
There are issues of what
style(s) of venting are
included in the estimates, the errors inherent in the measurements,
sampling statistics,
and the spatial and temporal averaging that is associated with each of
the individual
approaches. Thus while the reported values are of a reasonable order of
magnitude the
resulting estimates vary widely (from ~100 to ~10000 MW), have large
uncertainties
(often spanning an order of magnitude), and do not allow us to address
very
fundamental questions, for example, is the flux of heat steady or
varying through
time? We propose to take advantage of technological advances in deep
sea
autonomous vehicles to make precise measurements, achieving uncertainty
better than
20%, of the heat flux from the Main Endeavour Field (MEF)
examining its variation across a range of time scales. Funded by the
National Science Foundation
Investigators: Russ McDuff,
Fritz Stahr, Dana Yoerger,
and Al Bradley. Project Web..
Entrainment into rising hydrothermal plumes in the axial valley of the
central portion of the Endeavour Segment is of a magnitude that should
give rise to measurable convergence of flow of ocean water into the
valley. This project examines whether measurements of this flow can
serve as a proxy measure of the fluid discharge from venting sources by
comparing flux measurements from individual fields to the horizontal
fluid transport within the confines of the valley walls. Investigators:
University of Washington:
Russ McDuff (UW); Woods Hole Oceanographic
Institution: Dana Yoerger,
and Al Bradley; Institute of Ocean Sciences, Fisheries and Oceans Canada: Rick Thomson. Supported by NSF Grant OCE-0242736 and Fisheries and Oceans
Canada. Project Web.
Image correlation velocimetry or ICV involves the tracking of visible
features in a flow. Specifically the patterns associated with the
largest scales of turbulence undergo displacement, rotation and
deformation and these can be quantified by analysis of a sequence of
images closely spaced in time. We are working with the Center for In
Situ Exploration and Sample Return at JPL to apply their engineering
expertiese in digital imaging, embedded systems, and algorithms for
processing and data compression to develop a prototype in situ ICV
instrument for use at hydrothermal vents.
Collaborators: University of Washington: Russ McDuff, Tim Crone, William Wilcock; Jet Propulsion Laboratory: Greg Bearman, Lloyd
French and Gindi French.
Update 2/7/03 RMcD/mcduff@ocean.washington.edu