To what extent does terrestrial life "Follow The Water"?

Date

2010

Authors

Jones, Eriita
Lineweaver, Charles

Journal Title

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Volume Title

Publisher

Mary Ann Liebert

Abstract

Terrestrial life is known to require liquid water, but not all terrestrial water is inhabited. Thus, liquid water is a necessary, but not sufficient, condition for life. To quantify the terrestrial limits on the habitability of water and help identify the factors that make some terrestrial water uninhabited, we present empirical pressure-temperature (P-T) phase diagrams of water, Earth, and terrestrial life. Eighty-eight percent of the volume of Earth where liquid water exists is not known to host life. This potentially uninhabited terrestrial liquid water includes i) hot and deep regions of Earth where some combination of high temperature (T > 122˚C) and restrictions on pore space, nutrients, and energy is the limiting factor, and ii) cold and near surface regions of Earth, such as brine inclusions and thin films in ice and permafrost (depths less than ~1 km), where low temperatures (T < - 40˚C), low water activity (aw < 0.6), or both are the limiting factors. If the known limits of terrestrial life do not change significantly, these limits represent important constraints on our biosphere and, potentially, on others, since ~4 billion years of evolution have not allowed life to adapt to a large fraction of the volume of Earth where liquid water exists.

Description

Keywords

biosphere, limits of life, extremophiles, water

Citation

Source

Astrobiology 10.3 (2010): 349-361

Type

Journal article

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