Title: Bacteria increase arid-land soil surface temperature through the production of sunscreens

Abstract

Soil surface temperature, an important driver of terrestrial biogeochemical processes, depends strongly on soil albedo, which can be significantly modified by factors such as plant cover. In sparsely vegetated lands, the soil surface can be colonized by photosynthetic microbes that build biocrust communities. Here we use concurrent physical, biochemical and microbiological analyses to show that mature biocrusts can increase surface soil temperature by as much as 10 °C through the accumulation of large quantities of a secondary metabolite, the microbial sunscreen scytonemin, produced by a group of late-successional cyanobacteria. Scytonemin accumulation decreases soil albedo significantly. Such localized warming has apparent and immediate consequences for the soil microbiome, inducing the replacement of thermosensitive bacterial species with more thermotolerant forms. These results reveal that not only vegetation but also microorganisms are a factor in modifying terrestrial albedo, potentially impacting biosphere feedbacks on past and future climate, and call for a direct assessment of such effects at larger scales.

Authors:

Couradeau, Estelle ^[1]; Karaoz, Ulas ^[2]; Lim, Hsiao Chien ^[2]; Nunes da Rocha, Ulisses ^[2]; Northen, Trent ^[2]; Brodie, Eoin ^[3]; Garcia-Pichel, Ferran ^[4]

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+ Show Author Affiliations

1. Arizona State Univ., Tempe, AZ (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
4. Arizona State Univ., Tempe, AZ (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:

2016-01-20

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1255544

Alternate Identifier(s):

OSTI ID: 1379041

Grant/Contract Number:  

AC02- 05CH11231; AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Nature Communications

Additional Journal Information:

Journal Volume: 7; Journal ID: ISSN 2041-1723

Publisher:

Nature Publishing Group

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES