 EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes
and phenomena which shape our planet and our lives. EPOD will collect and
archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


 EPOD 20th - Calcite Crystals and Microbial Activity Within the Earth's
Crust

   September 18, 2020

    Press release Deep biosphere (1)

   We’re celebrating 20 years of Earth Science Picture of the Day during
   the month of September! Today’s photo features a popular EPOD from the
   past. Thanks to all of our followers (on the blog, Facebook, Instagram
   and Twitter) for supporting us. Thanks also to all of you who’ve
   submitted your photos. We’re most appreciative. This EPOD was
   originally published May 18, 2017.

   Photographer:  Henrik Drake
   Summary Author:  Henrik Drake

    May 2017 Viewers' Choice The photo above features  calcite
   crystals precipitated in response to  microbial activity deep within
   the Earth's crust -- shown in fractured  granitic rock in Sweden.
   These crystals (about 5 mm in height) act to provide an archive for
   tracking ancient microbial activity. The tweezers are included for
   scale.

    Methane-munching microbes, an analog for  extraterrestrial life,
   have been living in the deep  biosphere for some 400 million years.
   The knowledge about ancient life in the environment deep under our feet
   is extremely scarce. In numerous cracks down to depths of 1700 m (5,577
   ft) that have been partly sealed by crystals growing within them, an
   international team of researchers led by  Dr. Henrik Drake from
    Linnaeus University, Sweden, have traced fundamental, ancient
   microbial processes, including the production and consumption of the
   greenhouse gas, methane. This is thus far the most extensive study on
   ancient microbial activity in the  continental crust, and findings
   suggest that microbial methane formation and consumption are widespread
   in the bedrock here.

   This new knowledge of a deep source and sink for methane calls for a
   re-evaluation of the  carbon cycling within the vast continental
   crust and may even be significant in a long-term  global warming
   perspective.  Dr. Christine Heim of  the University of Göttingen,
   Germany, a co-author of the study, states that it's intriguing to find
   biomarkers of ancient organic remains having surface origins (land
   plants) preserved within calcite at such great depth. The nutrient
   source for the microbes at least partly seems to have been coming from
   the surface. This connection to the surface biosphere may explain why
   the marks of microbial activity abruptly disappear at around 700 to 800
   m in depth. So in essence, cracks in the Earth's crust and on other
   planets, believed to be omnipresent, may be the perfect graveyards for
   past biologic activities.

   Photo Details: Camera: SONY DSC-RX10; Lens: 24-200mm F2.8; Focal
   Length: 8.8mm (35mm equivalent: 24mm); Aperture: ƒ/2.8; Exposure Time:
   0.017 s (1/60); ISO equiv: 125; Software: Adobe Photoshop Lightroom 6.8
   (Windows).

Related EPODs

    EPOD 20th - Calcite Crystals and Microbial Activity Within the
   Earth's Crust  EPOD 20th - Hollister Offset  EPOD 20th - Anatahan
   Eruption of May 11  Reynisfjara Beach, Iceland  Color in Opals
    Encore - Folded Rock on the Portuguese Vicentine Coast
    More...

Geology Links

     *  Earthquakes
     *  Geologic Time
     *  Geomagnetism
     *  General Dictionary of Geology
     *  Mineral and Locality Database
     *  Mohs Scale of Mineral Hardness
     *  This Dynamic Earth
     *  USGS
     *  USGS Ask a Geologist
     *  USGS/NPS Geologic Glossary
     *  USGS Volcano Hazards Program

-
   Earth Science Picture of the Day is a service of the  Universities
   Space Research Association.

https://epod.usra.edu
 
