Home        >    Projects

Projects

The Role of Freshwaters in Canadian Carbon Budgets (CCAF, 1999-2001)

Investigating, predicting and modeling the effects of climate change upon the carbon cycling of Canadian freshwater systems.

Terrestrial ecosystems and wetlands generate and then lose dissolved organic carbon (DOC) and particulate organic carbon (POC) to soil water, streams, rivers and lakes through percolation and runoff processes. Natural and anthropogenic weathering of bedrock and surface deposits also contributes dissolved inorganic carbon (DIC) to surface waters. On a global scale, the loss of carbon of terrestrial origin to rivers, lakes and estuaries is relatively small compared to the large carbon fluxes from terrestrial plants to the atmosphere and from the oceans to the atmosphere. However, there are a number of factors that make this small flux quite significant. First, wetlands within terrestrial systems are the major source of carbon in streams and rivers in the Boreal ecozone, and subsequently an important source of organic carbon to lakes. Second, although much of the terrestrial carbon exported to surface waters is permanently stored in lake sediments, a large amount is returned to the atmosphere via photochemical and microbiological reactions, reactions that can be enhanced by acidification. Third, forest disturbance (fire and harvesting of trees and peat) affects carbon export to streams and lakes. The endpoint of these water sources is the open ocean, thus playing an important part in coastal productivity and the scale of the oceanic carbon sink. The aim of this research is to summarize and synthesize links between terrestrial carbon sources and aquatic carbon sinks in lake sediments, the atmosphere and estuarine sediments. The specific objectives are:

- to synthesize mass budgets for dissolved and particulate carbon for a range of aquatic systems that are affected by various land uses in Canada, i.e. to use existing long-term data sets to establish baseline conditions;

- to develop a predictive model to allow evaluation of the effects of climate change scenarios on aquatic carbon budgets, with an emphasis on sources and sinks;

- and to couple the model to a GIS-based regional model in order to evaluate the effect of shifting land use (e.g. agriculture, urbanization and forestry) and landforms (e.g. wetlands) on aquatic carbon sources

Information dated 2004 and can be found here

Home | Contact Us