Abstract

Biocrusts are aggregated crusts that exist on the soil surface of arid environments. They are complex microbial communities comprised of cyanobacteria, lichens, mosses, algae and fungi. Recently, biocrusts have gained significant attention due to their ubiquitous distribution and likely important ecological roles, including soil stabilization, soil moisture retention, carbon (C) and nitrogen (N) fixation, as well as microbial engineers for semiarid ecosystem restoration. Here, we collected three co-occurring types of biocrust (Cyanobacterial crust, Crustose lichen, and Foliose lichen) and their underlying soil from arid zones within Western Australia. Bacterial microbiome composition was determined through 16S rRNA gene amplicon sequencing to assess the extent of microbiome selection within the crusts versus underlying soil and biogeochemical measures performed to determine whether the crusts had significant impact upon the underlying soil for nutrient input. We determined that the bacterial communities of native biocrusts are distinct from those in their underlying soil, where dominant bacterial taxa differed according to crust morphologies. delta N-1(5) revealed that N-fixation appeared most evident in Foliose lichen crust (1.73 +/- 1.04 parts per thousand). Consequently, depending upon the crust type, biocrusts contained higher concentrations of organic C (2 to 50 times), total N (4 to 16 times) and available ammonium (2 to 4 times), though this enrichment did not extend to the soils underneath them. These findings demonstrate that biocrust communities are seemingly islands of biological activity in an arid landscape, uniquely different from their surrounding and underlying soil.

Keywords

biological soil crust; biocrust; 16S rRNA; microbial communities; delta N-1(5); semi-arid environment

Published in

Frontiers in Microbiology
2019, Volume: 10, article number: 2143
Publisher: FRONTIERS MEDIA SA

SLU Authors

• Yong, Jean W.H

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    
  • Curtin University
  • University of Western Australia

Sustainable Development Goals

SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Soil Science
Ecology
Environmental Sciences related to Agriculture and Land-use


Publication identifier

DOI: https://doi.org/10.3389/fmicb.2019.02143

Permanent link to this page (URI)

https://res.slu.se/id/publ/102032