For the deep biosphere, the present is not always the key to the past: what we can learn from the geological record.

Author(s)
Patrick Meister
Abstract

Microbial life below the Earth's surface (the deep biosphere) has probably varied significantly since the Archaean. Reconstructing changes in deep biosphere activity over geological timescales is necessary to understand its role in biogeochemical cycling. Even for the last few million years, such changes are often not captured by studying the distribution of present activity. However, several studies using samples from scientific drilling have revealed mineralogical, geochemical, isotopic and fossil organic molecule imprints in the sedimentary record that document rather different past deep biosphere conditions. Changing deep biosphere conditions can also be simulated using geochemical models. While some processes occurring in the past can be understood by comparing them with the present deep biosphere, others lack any modern analogue - they are defined as non-actualistic. A non-actualistic consideration of the deep biosphere is therefore essential for a better understanding of how Earth and life co-evolved through time.

Organisation(s)
Department of Geology
Journal
Terra Nova: the European journal of geosciences
Volume
27
Pages
400-408
No. of pages
9
ISSN
0954-4879
DOI
https://doi.org/10.1111/ter.12174
Publication date
2015
Peer reviewed
Yes
Austrian Fields of Science 2012
105101 General geology
Portal url
https://ucrisportal.univie.ac.at/en/publications/for-the-deep-biosphere-the-present-is-not-always-the-key-to-the-past-what-we-can-learn-from-the-geological-record(17b3ea59-1ef6-4f14-a687-a38ef3dfa298).html