Soil microbiomes as sources and sinks of greenhouse gases. Challenges and opportunities.

Biogeochemical cycles, including the microbially mediated carbon and nitrogen cycles, within soils govern the health status of environments, and are impacted, and impact upon, climate change. Anthropogenic activities have shifted the amounts and forms of carbon and nitrogen within soils. Whilst access to carbon and nitrogen is essential for plant growth and microbial food webs, excess carbon and nitrogen can lead to pollution via leaching into groundwater and the release of greenhouse gases, notably carbon dioxide, methane and nitrous oxide, contributing to global warming. In addition, changes in environmental conditions brought about by climate change, such as temperature increases, increased acidification of environments and shifts in soil moisture can also impact on microbial communities residing within soils leading again to shifts in biogeochemical cycling. Therefore, understanding the microbial communities associated with biogeochemical cycling is key to understanding healthy environments. This review summarises the known roles of the microbial community within biogeochemical cycling and the impacts on these communities from climate change. We also explore the additional opportunities for understanding impacts of climate change and future practices for sustainable agriculture via utilising soil bacteriophage within monitoring and their potential as biocontrol agents.