Abstract Detail

Biochemistry, metabolism, carbon flux

Hazen, Renee Elizabeth [1], Vitt, Dale H. [2], Ebbs, Stephen [3], Hartsock, Jeremy [3], House, Melissa [3].

CO₂ assimilation rates associated with four sedge species during reclamation in the Alberta Oil Sands Region.

Peatland ecosystems accumulate large amounts of organic matter due to low decomposition rates. The accumulated plant biomass within these high-latitude systems represents a large store of carbon. Peatlands of northeastern Alberta face major disturbances from surface mining wherein peatlands are removed in order to access bitumen deposits, a mix of petroleum, sand, clay and water. Peat removed during mining begins to decompose and release carbon dioxide. Reclamation is necessary to restore the native plant communities and their carbon-sequestering function. Sandhill fen is a peatland reclamation site located on Syncrude Canada Ltd.'s mine, north of Fort McMurray, Alberta. In 2008 Syncrude began a research initiative to develop reclamation techniques for peat-forming ecosystems, such as fens. Understanding species interactions with the substrate and surroundings is key for early plant establishment and initiation of organic matter accumulation. Research plots throughout Sandhill fen contain a variety of plant species native to Alberta’s peatlands. These species were planted in 2011 and 2012. Four sedge species were chosen for comparison based on differences in growth habit and size. Carex aquatilis and C. canescens are morphologically small sedges, while C. hystericina and Scirpus microcarpus are large. Additionally, C. hystericina and C. canescens have cespitose growth habits and C. aquatilis and S. microcarpus are stoloniferous. We hypothesized that CO₂ assimilation rates would differ between species. We expected assimilation rates to correlate with the differing size and/or growth habit of each species. Measurements were taken using enclosed plexi-glass chambers. The chambers were placed over the plants and infrared gas analyzers connected to the chambers measured changing CO₂ concentrations due to photosynthesis, photorespiration and heterotrophic respiration. Shade cloths were used to simulate 30%, 50%, and 100% shade scenarios. Results provide clear evidence of differences in CO₂ assimilation rate for each of the sedges. These results show patterns correlating to the species’ respective differences in growth habit and size. For example, both large species have higher rates of CO₂ assimilation. Of the two larger species, the stoloniferous S. microcarpus has a higher rate of CO₂ assimilation. Among the two smaller species, the stoloniferous C. aquatilis has a higher rate of CO₂ assimilation compared to the small cespitose species, C. canescens. A final analysis of the mean CO₂ assimilation rate, in which all species across Sandhill fen are included, is similar to whole ecosystem measurements taken in bogs of Alberta, a promising indication of peat development at the reclamation site.

1 - Southern Illinois University, Plant Biology, Life Science II, 1125 Lincoln Drive, Carbondale, Illinois, 62901, USA
2 - Southern Illinois University, Plant Biology, Carbondale, IL, 62901, USA
3 - Southern Illinois University, Life Science II, 1125 Lincoln Drive, Carbondale, Illinois, 62901, United States

Keywords:
CO₂
reclamation
Alberta
oil sands mining
Sedge
cespitose
stoloniferous
infrared gas analyzer
carbon flux.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PBC002
Abstract ID:363
Candidate for Awards:CSPB President's Award for Best Student Presentation