The proposed Deep Underground Science and Engineering Laboratory (DUSEL) provides a unique opportunity to study deep subsurface ecosystems, an endeavor that could fundamentally change the way we view the origin and early evolution of life on Earth, the search for novel materials, or the generation of energy to sustain future generations. We are guided by the over-arching question: What controls the distribution and evolution of subsurface life? Our hypothesis is that these controls are dominated by processes related to geology, geochemistry, geomechanics, and hydrology. Themes of scaling and the development of facies, or zones of similar characteristics, cut across all the processes. This project responds to the DUSEL S4 solicitation and has the ultimate goal to prepare a Preliminary Design Report describing experiments that will be developed as part of the DUSEL facility. Project planning activities include 1) refinement of the ecohydrological facies model using extensive Homestake data, 2) a workshop to refine goals, experimental designs, infrastructure, and education and outreach activities, and 3) writing the Preliminary Design Report and Work Breakdown Structure.

What we know about subsurface life has come from only a few studies of a few boreholes and deep mines. We are planning the first detailed study of a deep ecosystem in the context of the hydrology, geochemistry, and rock system state that sustain it at the former Homestake gold mine in the Black Hills of South Dakota where DUSEL has been proposed. The development of a long-term deep geosciences observatory at the Homestake DUSEL will revolutionize the field of deep subsurface ecohydrology. The opportunities for young scientists and international participation in such a facility will be tremendous. Results from the work will have wide ranging implications as 20% of the current earth's surface consists of a similar geologic setting. DUSEL also will facilitate experiential learning for K-12 through graduate school students working alongside world-class geoscientists. Current activities will focus in particular on South Dakota-based target audiences and programs.

Project Report

The deep subsurface continental biosphere has recently been recognized as containing functioning ecosystems that could profoundly influence the way we view the importance of microorganisms to deep crustal processes, the origin and early evolution of life on Earth, our search for novel life forms and enzymes, and our approaches to future energy production. Despite the fact that the deep subsurface comprises a significant fraction of the living carbon on our planet, it is poorly understood. This project was intended to design and implement scientific infrastructure, investigations, and experiments to characterize life in deep underground environments. The major goal of this project has been to address the question: What controls the distribution and evolution of subsurface life? In terms of infrastructure, we designed a multi-disciplinary program of coring, sampling, analysis, and in-situ experimentation at continental crustal depths ranging from less than 10 m to the worlds deepest drilling platform at 2.3 km. This ambitious program was designed for the proposed Deep Underground Science and Engineering Laboratory (DUSEL) at the former Homestake mine in South Dakota. Infrastructure plans generated by this project included details of the sites within the mine where drilling was to be conducted and a survey of state-of-the-art technology for drilling from within an underground facility. A conceptual hydrogeologic model was developed for groundwater flow in the vicinity of Homestake. A detailed work breakdown structure outlining timing and costs of the project was generated. However, the NSF decided not to continue its support of DUSEL, and so the application of the ideas and infrastructure plans developed as part of this project will likely have to be applied elsewhere. Discussions are underway to find a suitable underground facility for this project (e.g., the Soudan Mine in Minnesota or SNOLAB in Canada) and as well as to secure funding, possibly in part from the International Continental Scientific Drilling Program. Investigations of life in the deep biosphere as part of this project have taken advantage of a closely related NSF-funded study of deep fracture waters that are accessed via gold mines in South Africa at depths of ~1-3.7 km. Analyses of the sort envisioned for DUSEL-Homestake have been carried out on these deep fracture waters. These analyses have included 1. chemical analyses of major cations and anions, dissolved gasses, and dissolved organic carbon, 2. isotopic analyses of carbon, hydrogen, oxygen, and sulfur, 3. groundwater dating using stable isotopes, and 4. characterization of the microbial communities. A picture of the deep biosphere is emerging from these findings. As depth increases, the importance of buried and transported organic matter from photosynthesis diminishes and the dominant energy sources are derived from rock water interactions. These rock-water interactions generate hydrogen gas and methane, which support the growth of microorganisms. Bulk water ages in the deepest, most saline waters are 10-15 million years. The microbial communities are anaerobic. Methanogens are prevalent at shallow and mid depths; sulfate-reducing bacteria occur in the deepest samples. Spore-formers are common, but may be present only as inactive spores. Many of the microbes appear to be novel and indigenous to subsurface environments. Broader impacts of the project include development of a community of interdisciplinary scientists dedicated to studying the deep biosphere, increased awareness of deep subsurface ecosystems as active components of the biosphere, and education of undergraduate and graduate students. Discussions carried out in this project and the documents generated have been of value to other groups, e.g., the Sloan Foundation-funded Deep Carbon Observatory and the International Scientific Drilling Program.

Agency
National Science Foundation (NSF)
Institute
Division of Earth Sciences (EAR)
Application #
0918801
Program Officer
David Lambert
Project Start
Project End
Budget Start
2009-10-01
Budget End
2013-09-30
Support Year
Fiscal Year
2009
Total Cost
$128,020
Indirect Cost
Name
New Mexico Institute of Mining and Technology
Department
Type
DUNS #
City
Socorro
State
NM
Country
United States
Zip Code
87801