NORA Major Achievments
The overarching scientific goal of NORA is to understand the biochemistry and ecophysiology that underpins N2O emissions, improve the assessment of the emissions and to find mitigation options. This was reached through the integration of detailed biochemical approaches, microbiology and physiology studies of relevant organisms (model organisms and newly isolated strains), microbial ecology of complex systems (soils and wastewaters), field emission studies and advanced technological development. The specific key objectives were also reached:
- Mathematical models of model organisms have been developed and used to improve understanding of the regulatory biology of denitrification.
- Increased knowledge was obtained about regulatory responses of isolated key strains and relationships between genotypes and phenotypes.
- Relationships between microbial community function and composition were characterized and quantified in relation to selected environmental factors (fertilizer regime; pH; copper).
- Predictive models were used to assess and predict the influence of land management on N2O emissions. Read more here
NORA Research Highlights
- Novel regulatory mechanisms were revealed, which determine the efficacy by which different denitrifying bacteria act as sinks or sources for N2O. The dependency of pH and Cu for correct assembly of the N2O reductase was confirmed and novel, putative Cu chaperones were detected.
- In-depth assessment of the potential N2O production by fungal metabolism which demonstrate that its contribution to N2O emission is marginal compared to that of heterotrophic bacterial denitrification.
- Improved understanding and assessment of N2O production/reduction by DNRA organisms (Dissimilatory Nitrate Reduction to Ammonia) suggest that these organisms are sinks rather than sources of N2O.
- Comparative physiology of ammonia oxidizing archaea (AOA) and bacteria (AOB) indicate that so-called nitrifier denitrification is a marginal source of N2O.
- N2O emissions can be reduced by slow release fertilizers; and by NO3- (versus NH4+-) based fertilizers
- Non-denitrifier bacteria carrying nosZII genes could act as sinks for N2O emissions from agricultural soils.
Wastewater treatments plants harbor organisms with strong N2O reducing capacity, which should be further exploited to reduce point emissions.
- A novel field robot for measurements of N2O emissions has been developed, allowing effective monitoring of field experiments.
- Implementation of predictive biogeochemical models showing good agreement with measured N2O emissions in field trials. Read more here