The Impact of Reclamation and Vegetation Removal on Compositional and Functional Attributes of Soil Microbial Communities in the Athabasca Oil Sands Region

• Author / Creator

  Santana Martinez, Juan Camilo

• Large-scale mining for oil extraction in the boreal forests of Northern Alberta has led to a disturbance footprint of ~ 900 km2 of land; which, under regulations from the government of Alberta, must be reclaimed to equivalent land capabilities using soil materials salvaged and conserved during land clearing. Microorganisms play pivotal roles in soil nutrient cycling and plant growth during land reclamation and are sensitive to anthropogenic disturbances, making them potential markers of ecosystem health. Thus, the objective of this study was to determine the impact of reclamation and vegetation removal on the composition and function of soil microbial communities in the Athabasca Oil Sands Region (AOSR). While the majority of the cover materials are lowland-derived peat-mineral mix (PMM), the upland-derived forest floor-mineral mix (FFM) is the most suitable as a reclamation substrate; however, FFM is far less abundant. Therefore, as a strategy to maximize the limited supply of forest floor soil, this study also investigated diluting this material with sand. The concept of equivalent land capability is ambiguous; thus, I evaluated bacterial community composition (BCC) via high throughput sequencing of 16S rRNA genes and functional diversity by community-level physiological profiling (CLPP). The ranges of variability for these factors observed in soils with vegetation removed and reclaimed soils were compared to that of undisturbed reference soils. Vegetation removal changed the structure of the soil microbial community with some sites overlapping with the range of natural variability, and increased the overall diversity, within-community interactions, and heterogeneity. Reclamation shifted the microbial community structure to a greater extent, placing it outside the range of natural variability. Different reclamation substrates resulted in distinct microbial communities, with forest floor material (FFM) showing the highest
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  level of similarity to the range of natural variability and peat mineral mixture (PMM) showing the least. BCC, functional diversity, and soil edaphic parameters all had similar results, but BCC showed the greatest ability to resolve differences between treatments. Altogether, my results suggest both reclamation and vegetation removal alter compositional and functional attributes of the microbial communities of the natural boreal forests soils. Furthermore, BCC provided the greatest information about the impacts of mining practices. Thus, BCC holds promise as a marker of reclamation efficacy and trajectory.

• Subjects / Keywords

  • soil microorganisms
  • land reclamation
  • oil sands

• Graduation date

  Spring 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-twdx-b421

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.