Campus Units

Ecology, Evolution and Organismal Biology

Document Type

Article

Publication Version

Published Version

Publication Date

1-2020

Journal or Book Title

Ecosphere

Volume

11

Issue

1

First Page

e02973

DOI

10.1002/ecs2.2973

Abstract

Many soils are deep, yet soil below 20 cm remains largely unexplored. Exotic plants can have shallower roots than native species, so their impact on microorganisms is anticipated to change with depth. Using environmental DNA and extracellular enzymatic activities, we studied fungal and bacterial community composition, diversity, function, and co-occurrence networks between native and exotic grasslands at soil depths up to 1 m. We hypothesized (1) the composition and network structure of both fungal and bacterial communities will change with increasing depth, and diversity and enzymatic function will decrease; (2) microbial enzymatic function and network connectedness will be lower in exotic grasslands; and (3) irrigation will alter microbial networks, increasing the overall connectedness. Microbial diversity decreased with depth, and community composition was distinctly different between shallow and deeper soil depths with higher numbers of unknown taxa in lower soil depths. Fungal communities differed between native and exotic plant communities. Microbial community networks were strongly shaped by biotic and abiotic factors concurrently and were the only microbial measurement affected by irrigation. In general, fungal communities were more connected in native plant communities than exotic, especially below 10 cm. Fungal networks were also more connected at lower soil depths albeit with fewer nodes. Bacterial communities demonstrated higher complexity, and greater connectedness and nodes, at lower soil depths for native plant communities. Exotic plant communities’ bacterial network connectedness altered at lower soil depths dependent on irrigation treatments. Microbial extracellular enzyme activity for carbon cycling enzymes significantly declined with soil depth, but enzymes associated with nitrogen and phosphorus cycling continued to have similar activities up to 1 m deep. Our results indicate that native and exotic grasslands have significantly different fungal communities in depths up to 1 m and that both fungal and bacterial networks are strongly shaped jointly by plant communities and abiotic factors. Soil depth is independently a major determinant of both fungal and bacterial community structures, functions, and co-occurrence networks and demonstrates further the importance of including soil itself when investigating plant–microbe interactions.

Comments

This article is published as Upton, Racheal N., Aleksandra Checinska Sielaff, Kirsten S. Hofmockel, Xia Xu, H. Wayne Polley, and Brian J. Wilsey. "Soil depth and grassland origin cooperatively shape microbial community co‐occurrence and function." Ecosphere 11, no. 1 (2020). doi: 10.1002/ecs2.2973.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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