The effect of wildfires on dissolved carbon and water chemistry in subarctic streams

Under future climate scenarios the western Canadian sub-arctic is expected to experience a high degree of warming, increasing the incidence of wild fires

In this project I investigate the effect of burnt catchments on stream carbon dioxide and methane emissions and overall water chemistry

Photo Credit: NRC-CFS

Molecular characterization of dissolved organic matter

The natural dissolved organic matter pool in freshwaters is extremely complex and requires advanced techniques for characterization of its composition

I apply ultrahigh-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) to help understand the molecular composition of DOM and its potential links to DOM quality and reactivity

Large-scale landscape drivers of dissolved carbon in northern river networks

Half of the earth's surface freshwater is at high latitudes but the vastness and remoteness makes sampling difficult

In this project I developed predictors of dissolved carbon in rivers based on the watershed landscape

In particular, use of remotely sensed drivers to for prediction at the biome scale

Stream network modelling and upscaling

Use of geographic information system to model stream networks at large scales and dissolved carbon throughout the landscape

Provides estimates of emissions and carbon export at regional scales

Regional stream network emissions show emergent properties that could apply to biome or global scales

Flow of nutrients and organic matter between terrestrial and aquatic ecosystems

The terrestrial landscape is an important source of carbon and nutrients to aquatic systems

Reactive interfaces such as the soil-stream interface are especially important for these transfers

I show the composition and importance of dissolved organic matter lost in this interface in sustaining CO­2 emission

Whole watershed characterization

The watershed landscape contributes non-point sources of carbon, nutrient and contaminants at large scales

To fully understand the human impacts on rivers and downstream lakes the entire contributing watershed must be sampled and characterized

I investigated the effects of human impacts on dissolved organic matter quality and found urbanization causes disproportionate changes compared with agriculture