Structure and function of microbial communities at the soil atmosphere interface

Lead Research Organisation: University of Warwick
Department Name: School of Life Sciences

Abstract

The top few millimetres of soil forms a microbiotic layer, known as the Biological Soil Crust (BSC), that consists of unique communities of bryophytes, algae, cyanobacteria, microfungi and bacteria. At the soil surface the BSC is exposed to exclusive conditions, which gives it a distinct soil chemistry and community structure in comparison to bulk soil. These properties allow it to play irreplaceable roles in nitrogen and carbon fixation, water infiltration, sediment production, protection from soil erosion and breakdown of pesticides, which are all of great agricultural and environmental importance. However, previous studies, which often focus on arid soils, have suggested that the ability for the BSC to perform these roles often depends on the community structure, which has been proven to differ greatly both temporally and spatially. Consequently, the diversity, composition and dynamics of the microbiology at the soil surface layer remains poorly understood, and the nature of different microbial communities contribution to key functions is unresolved, especially in an agricultural context in temperate soils.

In this project, next generation sequencing methods will be used to understand the environmental factors that determine composition and functioning of the BSC in agricultural fields in temperate soils. Using landscape sampling approaches, the roles of geographical distance, local environment and seasonable variables that determine composition of the soil surface community will be resolved. Molecular approaches will be used to characterize the microbial community organisation and its ecological function. These approaches will include DNA and RNA extraction and purification, PCR, nucleic acid sequencing using next generation platforms and bioinformatics analysis. Lastly, the way in which community composition affects the degradation of pesticides will be investigated to identify relationships between soil surface community composition and ecosystem function.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M01116X/1 01/10/2015 30/09/2023
1643131 Studentship BB/M01116X/1 05/10/2015 30/09/2019 Christopher O'Grady
 
Description This project for the first time examined the roles of soil surface microbiomes in a temperate agricultural environment, which had previously only been investigated in arid ecosystems. Results here showed that biological soil crusts are capable of forming in temperate agroecosystems, and form a large physical barrier that separates the bulk soil and soil surface. Additionally, using next generation sequencing techniques, results here showed that microbial communities at the soil surface have distinct community structure (bacterial, fungal, protist and phototrophic) relative to bulk soil (amplicon sequencing). Using shotgun metagenomics, this project further predicted that soil surface communities had large roles (relative to lower soil depths) in numerous biogeochemical cycles, which has prior not been considered in temperate agroecosystems.
Exploitation Route This project focused on two sampling sites, results here warrant further research to explore whether these results are applicable to other temperate agroecosystems containing different soil types and different cropping regimes.
Sectors Agriculture, Food and Drink