Interdisciplinary Groups: Controls on hydrothermal circulation, fluid composition, and biological distribution in space and time

Moderator: Meg Tivey

Participants (list your name here):
    •    Jen Houghton
    •    Christof Meile
    •    Meg Tivey
    •    Alden Denny
    •    Florencia Prado
    •    Gibert Flores
    •    Kristen Myers
    •    John Jamieson
    •    Helene Ver Eecke
    •    Liang Han
    •    Mikaella Rough
    •    Nick Pester
    •    Kayla Lewis
    •    Bill Seyfried
    •    Chuck Fisher

    •    Bob Lowell

Controls on hydrothermal circulation, fluid composition, and biological distributions in space and time

Goal: Integration of existing datasets
Synthesis of new ideas, approaches, models
Papers/New collaborations

Deep controls on hydrothermal circulation and fluid composition in space and time
comprehensive data sets exist on fluid chemistry
other key information needed:
micro-seismicity data at EPR, Endeavour
multi-seismic AMC, location, size (cross-axis, along axis extent), layer 2a
any information on permeability??? porosity... Is there consistency between constraints from models vs. micro-seismicity
Yes, we have information on permeability for the EPR from microearthquake data. The results on permeability are consistent with previous models. Please see Stroup et al., 2009, published 22 Sept. 2009 in GRL. (posted by D. F. Stroup)
information from ophiolite drilling and tectonic windows
heat-flux models- need composition of substrate (andesitic vs. balsatic), physical models, geochemical models, and coupled reactive transport models
New collaborations: new experimental technique (mikella...); pull in rock mechanics people (This would include Leonid Germanovich)
Lau: not very high temps (no two-phase separation observed); Endeavour: possibly waning temperatures, chlorinity (southern field) Different temperatures, reaction conditions between ISS's
Heat flux data (vent field scale): Main Endeavour field survey, nothing comparable at Lau nor EPR
finer scale (sides of structures, individual orifices) heat flux data (not from Lau)
Brine and vapor mixing in deep sub-surface: could be good cross-comparisons, Endeavour vs EPR (Lowell and Lewis are working on Endeavour and eventually plan to work on EPR)
Putting things into a tectonic framework of faults on the surface

Mixing and consequences 50 m below to 50 m above seafloor
How deep do people think mixing occurs? How far above the seafloor? Anything taking a zero Mg fluid...Mixing can occur vvery deep between phase separated and heated non-phase separated 0 MG fluid as well as within all of layer 2A (Lowell and co-authors)
Diffuse fluid compositions for Main Endeavour field, HRF, Mothra; EPR- Ty, IO, Tica; Lau- few from every site (Wheat and Mottl et al.)
Voltametry measurements: EPR, Lau, Endeavour: SUAVE, McLane, Osmo
Electorchemistry: EPR, MEF (Seyfried)
Use data for conservative and non-conservative mixing processes; Abiotic v. Biotic alterations
Biological feedbacks: Microbial, meiofaunal, megafaunal interactions that may occur and influence mixing (lateral diffusion across a surface), how animals change the sulfide/temperature ratio- sulfide consumption, and dispersion of fluids; Are similar things being done at either EPR or Endeavour? EPR- Luther, Shank, Johnson (Galapagos);
Vent deposits: Voltametry against vent deposit and at exterior of biological community at Lau and EPR (Luther et al.); nothing comparable at Endeavour that we know of, but have descriptive mapping of communities
Biofilms: EPR, Endeavour, Lau
Mosaics: Lau, EPR, Endeavour; to what extent were they sampled afterwards?
Microbial activity in the sub-surface: community composition information from diffuse flow indicating higher temperatures in the sub-surface than whats measured
Need information on near surface crustal structure (have magnetics data, EPR- 9N)
Fluid flow rate data from Germanovich at Endeavour, not at Lau, EPR soon by Germanovich?
Individual heat flow measurements at MEF structures (Germanovich et al)
Magnetics coverage: 3 northern vent fields at Lau (not processed), EPR ?
Microbial information in soft areas of vent deposits: plenty from Endeavour and Lau, few from EPR
Background hydrography, physical oceanography: currents at Endeavour, EPR, no data on bottom currents at Lau;
Larval dispersal: lots of info at EPR; Endeavour? Metaxis?; Lau- Kim 2005, settlement substrates recovered in 2009
New ideas/approaches other than models?
Papers, New collaborations? Vent deposit group, microbiologists are chatting..., high temperature fluid chemists group should get chatting..., collaboration between physical and biological measurements (better constrain chemical fluxes using physical and geochemical measurements, Girguis, Lowell, Holden & Germanovich)
Anyone already working on cross ISS comparisons?

Modeling on a variety of different scales: physical mixing, geochemical models, reactive transport models

Discussion items?

    •    Are there statistical (or other) methods of quantifying the connections between circulation, composition, biology