Dr Sergio E. Morales (Microbiology & Immunology) was recently awarded $20,000 by the Dean's Research Advisory Committee for a project on uncovering regulatory pathways for greenhouse gas (N20) emissions through metagenomic and metatranscriptomic analysis of agricultural soils.
Dr Morales will be using an integrated approach that applies molecular tools, high throughput sequencing, bioinformatics and field based ecosystem measurements at the University of Otago to explore the mechanisms controlling nitrous oxide (a potent greenhouse gas) emissions from soils.
Greenhouse gas levels have been steadily increasing in the last 100 years and the global community has responded by enacting international mitigation agreements and funding scientific research in order to understand the mechanisms controlling both man made and natural emissions.
In New Zealand, research has shown that 50% of greenhouse gas emissions are produced by the agriculture sector, with the dominant form of emissions from soils being nitrous oxide (N2O).
This is of great significance considering that N2O's greenhouse warming potential (a measure developed to compare the ability of each greenhouse gas to trap heat in the atmosphere) is 310-fold greater than that of CO2.
In New Zealand N2O emissions are linked to ruminant livestock excreta deposition onto pastures; however, the mechanisms that dictate whether a given soil is more or less susceptible to emit or retain excess nitrogen is not completely understood.
Recent studies by Dr Morales demonstrated how microbial community changes could predict whether a soil is a net sink or source of greenhouse gases, adding support to the notion that microbial populations are mediating uptake and release of gases.
Subsequent studies by other researchers have found similar links and suggest that managing lands to conserve or restore specific microbial populations could mitigate greenhouse gas emissions. For that strategy to be a viable option we must first understand the mechanisms that select for microbial populations, and activity levels, leading to maximum or minimal gas emissions.
Experiments, funded by the Otago School of Medical Sciences and in collaboration with AgResearch, will aim to understand how genomic changes within specific bacterial populations affect their population dynamics and activities in field sites monitored for N2O emissions.
The study will take advantage of new high throughput sequencing technology that enables in depth sequencing of genomes directly from soils and, in combination with on-going research, will provide a holistic view of how changes in microbial populations, or their transcriptional activity, affect N2O emissions.
This is a key step if models for predicting N2O emissions from soils are to include biological data, and if we are to manage lands in ways that take into account microbial populations, which are considered the drivers of biogeochemical cycling.