CFRAW Research Themes
Research under the CFRAW Project is unified by three major themes. Click on the links below to read more about each theme.
Carbon Dynamics: Tracking materials through the food web
The goal of our project is to assess several classes of wetland differing in reclamation type (reference vs. soft-tails
amended), age (young vs. older), and organic base (poor vs. rich; vegetative materials vs. hydrocarbon-derived
materials). We are now ready to predict the types of biological communities that should develop in these water
bodies and how quickly they should attain their natural state, provided they maintain an adequate food base.
To do this, we must assess how efficiently energy is processed by the biota, and whether the ultimate carbon
source (plant production, algal production, imported detrital material, degraded bitumen, or byproducts) changes
as the wetlands mature. Figure 2 summarizes the various compartments in which organic carbon resides in local
wetlands systems.
Fig. 1. Schematic diagram showing the functional compartments of a constructed wetland food web. The arrows show the direction in which materials move. Work to date has quantified the amount of biomass for many of the compartments in selected
wetlands. However, if we want to understand how wetlands will develop and whether the food webs are sustainable, we have to know
how quickly and how much material is moving between the compartments. (Jan Ciborowski, University of Windsor) |
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Each of the carbon sources has a distinct elemental signature that is identifiable by the ratio of stable isotopes of
carbon, nitrogen and sulphur. These signatures also become part of the biota that derive their energy from the
sources. We can deduce the rates at which carbon moves among the compartments by
looking at accumulation (production) and by tracking the losses (as respiration) that occur during the transfer
between compartments. Furthermore, by examining stable isotope signatures, we can determine the
sources of the carbon that contribute to production of each trophic level of the biota.
Biological effects of oil sands process materials (OSPM)
In addition to ‘metabolic’ carbon flow, we can study the parallel transport of constituents of potential concern
(PAHs, naphthenic acids, arsenic, selenium, trace metals) through the biota to the wildlife that form the top of the
food web. In addition to using standard techniques for assessing bioaccumulation potential and health/stress effects
in biota, we will adapt in situ protocols to suit the unique environmental conditions of the local constructed
wetlands. Data on each constituent will be summarized to provide a ‘life cycle’ risk assessment model on the
ultimate fate and risk of these materials in the mature ecosystem. An example of this is shown in Figure 2, which summarizes the effect of OSPM on the survival and growth rate of the wood frog (Rana sylvatica).
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Fig. 2. Survival rates and mean body mass of wood frogs (Rana sylvatica) raised in different classes of wetlands. Wetlands up to seven years of age were categorized as young, while those over seven years were categorized as old. OSPM wetlands were those formed from oil sands process materials, while reference wetlands were naturally formed wetlands. (Blair Hersikorn, University of Saskatchewan) |
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Predicting changes and recommending reclamation strategies
The CFRAW Project will provide fundamental knowledge on the succession and energy flow processes in both
natural and constructed wetlands leading to tools that will:
- Let us set improved criteria for evaluating the biological health of a wetland.
- Provide improved forecasts of the time required to achieve full restoration (e.g. Figure 3).
- Lend guidance as to optimal amendment strategies (application of tailings, stabilizing substrates such as sand or coke, amounts and kinds of stockpiled materials, best candidate species for revegetation).
- Generate carbon budgets and anticipate net fluxes to/from the atmosphere.
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Fig. 3. Chronosequences of a reclaimed wetland (top) and a natural wetland (bottom). While plant colonization is slower in reclaimed wetlands (versus natural wetlands), plant colonies in both classes expand and contract based on glowing conditions. (Marie Claude Roy, University of Alberta) |
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Ultimately, research results from the CFRAW Project will provide guidance to industrial partners regarding the most effective reclamation strategies and techniques for developing viable systems and for monitoring their developmental progress and health.
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