Managing Global Resources for a Secure Future

2017 Annual Meeting | Oct. 22-25 | Tampa, FL

96-2 Lessons from the Field: Insights for Modelling N2o Emissions from Riverine Ecosystems.

See more from this Division: Special Sessions
See more from this Session: Special Session Symposium--How Can We Improve Our Estimates of Indirect N2O Emissions?

Monday, October 23, 2017: 1:55 PM
Tampa Convention Center, Room 21

Helen Baulch1, Madeline Rosamond2, Jason Venkiteswaran3, Sherry Schiff2, Nick Dylla4 and Colin Whitfield4, (1)University of Saskatchewan, Saskatoon, SK, CANADA
(2)University of Waterloo, Waterloo, ON, Canada
(3)Wilfrid Laurier University, Waterloo, ON, Canada
(4)University of Saskatchewan, Saskatoon, SK, Canada
Abstract:

Nitrous oxide (N2O) emissions are globally significant to climate and ozone depletion.  Aquatic emissions represent a win-win opportunity for mitigation, with efforts to improve water quality expected to reduce N2O emissions – but a key step in mitigation is a better a priori understanding of what those emissions actually are. Approaches to modelling N2O emissions in aquatic ecosystems are easy to criticize. Complex, process-based models are impacted by overparameterization and data limitations, yet simpler methods may overlook key controls. Along the way, we must consider modelling goals – from estimating national and global emissions to understanding how to mitigate emissions, or identify hotspots. IPCC-based methods for estimating indirect agricultural emissions have been highly criticized – yet no simple, tractable replacement has been identified that allows reliable emissions estimation with limited data. Here, we revisit our past work – assessing temporal and spatial variation in N2O emissions from rivers and streams, and comparing these to estimates using the empirically-derived EF5-g – supplementing the analyses with new data, and data from varied ecosystems, including systems strongly impacted by anoxia. We assess several proposed approaches to estimating N2O emissions in watersheds with a variety of hydrological regimes, land covers, and anthropogenic impacts. We use instantaneous field-based flux data to identify and assess hotspots and hot moments. Then, we return to the scale for which the EF5-g was really intended – assessing relationships between annual emissions and nitrate export across a suite of ecosystems for which we could obtain data. We end by identifying key data gaps and opportunities to help achieve robust, but simple, N2O accounting in freshwater systems.

See more from this Division: Special Sessions
See more from this Session: Special Session Symposium--How Can We Improve Our Estimates of Indirect N2O Emissions?