Johnstone, Emma Lucy (2020) The impact of extreme weather events on soil microbial communities. PhD thesis, University of Warwick.

PDF WRAP_Theses_Johnstone_2020.pdf - Submitted Version Embargoed item. Restricted access to Repository staff only until 27 April 2023. Contact author directly, specifying your specific needs. - Requires a PDF viewer. Download (8Mb)

Request Changes to record.

Abstract

The intensity, duration and frequency of extreme weather events, which are defined as unseasonable, unpredictable or severe weather phenomena, are predicted to continue increasing around the World. Flooding and drought, which can result from extreme weather events, cause widespread damage to ecosystems and impacts on human health. Soil ecosystems are home to diverse communities of microorganisms that perform a variety of functions, including biogeochemical cycling, the production and consumption of greenhouse gases, and the control of plant growth through direct and indirect interaction pathways. Previous work has found that flooding and drought can alter a number of soil physio-chemical properties, and can disrupt the composition and function of soil microbial communities. Here we investigated how soil microbiomes are affected by 1. Land use, and the seasonal timing and duration of flooding 2. Multiple weather events, which result in combinations of flooding and drought. Using DNA amplicon sequencing we found that across land-uses (arable and high mid and low intensity grasslands) the community composition of the soil microbiome is significantly changed by summer but not winter floods, and that microbiome composition recovered rapidly after short four week floods but persisted for at least a year following eight week floods. Impacts of flooding on bacterial and fungal operational taxonomic units were specific to each land-use but generally across land-uses responses of specific functional groups of soil microbes were similar. Longer floods resulted in higher emissions of methane but lower emissions of nitrous oxide compared to shorter floods, with the magnitude of responses dependent on land use. qPCR analysis of functional genes in combination with predicted metagenome analysis showed that microbial pathways related to methane production, but not nitrogen cycling, were altered during flooding, with land-use specific responses. Finally, using DNA amplicon sequencing we found that compound weather events, including combinations of flood and drought, led to specific impacts on microbial community compositions. Prior weather events led to legacy effects on microbial communities if followed by a flood, but not a drought. Together the results presented here demonstrate that future increases of extreme weather events may have detrimental and long lasting impacts on not only the composition of the soil microbiome but also on their ecosystem functions.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	G Geography. Anthropology. Recreation > GB Physical geography Q Science > QC Physics Q Science > QH Natural history Q Science > QR Microbiology
Library of Congress Subject Headings (LCSH):	Soil ecology, Soil microbial ecology, Soil microbial ecology -- Effect of floods on, Soil microbial ecology -- Effect of drought on, Droughts, Floods
Official Date:	November 2020
Dates:	Date Event November 2020 UNSPECIFIED
Institution:	University of Warwick
Theses Department:	School of Life Sciences
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Bending, G. D. (Gary D.) ; McNamara, Naill ; Van der Gast, Christopher J.
Sponsors:	Natural Environment Research Council (Great Britain)
Format of File:	pdf
Extent:	xvii, 258 leaves : illustrations
Language:	eng

Request changes or add full text files to a record

Repository staff actions (login required)

View Item