page_title: Deep biosphere
section_title: Sample collection
hierarchical_section_title: Deep biosphere / Scientific methods / Sample collection
caption_attribution_description: English: Microbial life has been sampled in deep mines.
context_page_description: The deep biosphere is the part of the biosphere that resides below the first few meters of the surface. It extends down at least 5 kilometers below the continental surface and 10.5 kilometers below the sea surface, at temperatures that may reach beyond 100°C. It includes all three domains of life and the genetic diversity rivals that on the surface.
  The first indications of deep life came from studies of oil fields in the 1920s, but it was not certain that the organisms were indigenous until methods were developed in the 1980s to prevent contamination from the surface. Samples are now collected in deep mines and scientific drilling programs in the ocean and on land. Deep observatories have been established for more extended studies.
  Near the surface, living organisms consume organic matter and breathe oxygen. Lower down, these are not available, so they make use of "edibles" such as hydrogen, methane, reduced sulfur compounds and ammonium. They "breathe" electron acceptors such as nitrates and nitrites, manganese and iron oxides, oxidized sulfur compounds and carbon dioxide.
context_section_description: The ocean floor is sampled by drilling boreholes and collecting cores. The methods must be adapted to different types of rock, and the cost of drilling limits the number of holes that can be drilled. Microbiologists have made use of scientific drilling programs: the Ocean Drilling Program (ODP), which used the JOIDES Resolution drilling platform, and the Integrated Ocean Drilling Program (IODP), which used the Japanese ship Chikyū.
  Deep underground mines, for example South African gold mines and the Pyhäsalmi copper and zinc mine in Finland, have provided opportunities to sample the deep biosphere. The deep subsurface has also been sampled at chosen or proposed nuclear waste repository sites (e.g. Yucca Mountain and the Waste Isolation Pilot Plant in the United States, Äspö and surrounding areas in Sweden, Onkalo and surrounding areas in Finland, Mont Terri in Switzerland). Scientific drilling of continental deep subsurface has been promoted by the International Continental Scientific Drilling Program (ICDP).
  To allow continuous underground sampling, various kinds of observatories have been developed. On the ocean floor, the Circulation Obviation Retrofit Kit (CORK) seals a borehole to cut off the influx of seawater. An advanced version of CORK is able to seal off multiple sections of a drill hole using packers, rubber tubes that inflate to seal the space between the drill string and the wall of the borehole. In sediments, the Simple Cabled Instrument for Measuring Parameters In-Situ (SCIMPI) is designed to remain and take measurements after a borehole has collapsed.
  Packers are also used in the continental subsurface, along with devices such as the flow-through in situ reactor (FTISR). Various methods are used to extract fluids from these sites, including passive gas samplers, U-tube systems and osmotic gas samplers. In narrow (less than 50 millimeter) holes, polyamide tubes with a back-pressure valve can be lowered to sample an entire column of fluid.
caption: Researcher sampling fluid from a deep mine.[15]
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