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Initial Geochemical and Microbiological Characterization of Henderson Fluids. How does knowledge of the site-specific chemistry at Henderson enhance our ability to identify subsurface microbial organisms (phylogentically and functionally)
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-- and their direct dependency upon fluid-rock interaction?
Tom Kieft (New Mexico Tech)
Alexis Templeton (University of Colorado – Boulder)
BIOSCIENCE SAMPLING TEAM
Templeton: Henderson DUSEL Capstone Workshop May 4-7th
in deeply-sourced, hot fluids:
Flowing boreholes variably mixed with oxygen
Fluid Chemistry: 7025 level
Warm, ~40C; pH 5.9 to 6.2
Dissolved O2: 0.3 to 3.8 mg/L
High DIC (~30 mM)
High Mn2+, Fe2+ (1 to 20 mM)
High SO42- (4 to 48 mM)
Trace metals: Zn > Ni > Mo
Low (but detectable) organics (50 mM)
Abundant nitrogen species:
includes NO3-, NO2- ,N2O, NH4+
O2 concentrations increase
as borehole flow-rate decreases
From D1 D3
O2 levels drop 1000x within 1 hour of packer-insertion
High CO2 important for autotrophic growth
Natural Fracture Surface: Degassing CO2
Can also detect N2O (6-18 microM), only low CH4 (sub-microM), and H2 not measured yet.
Fe2+ rapidly oxidizes and oxide and sulfate minerals precipitate
New minerals hard to structurally identify – relatively amorphous
Abundant Mn(IV)-oxides form black mineral coatings on the tunnel walls.
Mn(II) in fluids
Surprising abundance of
Eukaryotic fungal sequences..
Data from John Spear, CSM
Dominated by uncultured beta-Proteobacteria (e.g. Japanese Gold Mine): 80%
Fluids with high Fe, Mn, sulfate, NH4+, N2O (7025-D4) post-packer:
Abundant delta-Proteobacteria (SRB)
Remarkable diversity (~27 other groups)Second assessment: Microbial Diversity in fluids of varying chemistry(samples only separated by meters….)
Thermophilic Metal-oxidizing bacteria?
Water and Mat samples:
*site-specific Henderson medium*
with and without organics
stabilized on mineral surfaces
culture at 40°C-55°C
Microbes more abundant in the Fe-oxide mats
Rapid growth on Mn-media at 50°C using D4 mineral mat! First 3 isolates being sequenced
Now target anaerobic enrichments:
Isolates for biochemical and proteomic studies
In-situ biofilms recently
extracted for analysis
NH4+, NO2-, NO3- and N2O all abundant (naturally or not?)