ProjectSpatial modelization of carbon, nitrogen and phosphorus peatland stocks
Peatlands have accumulated important amounts of organic matter since the beginning of the Holocene. This organic matter accumulation is described as peat, that globally stores large amounts of carbon (C), nitrogen (N), and phosphorus (P). Regional estimations of C and nutrients stocks have seldom been quantified. Moreover, peat depth variability and biophysical and physical variables are often not included in actual peat C, N, and P pool size estimations. The goal of this thesis is to provide an estimation of peat C, N, and P pool sizes for a regional county of southern Quebec by modeling peat depth variations and by using biophysical and physical variables to discriminated peat C, N, and P storage among peatland types. Manual peat depth probing showed significant differences in peat depth among peatland types. Mean peat depth of bogs was 4.4 m, while fens and forested peatlands mean peat depths were of 2.3 and 2.0 m, respectively. Modeling of peat accumulation basin by spatial interpolation took these peat depth variations into account, among peatland types. The relationships between peatland area and peat C and N stocks were statistically different between bogs and fens, and bogs and forested peatlands. Peat P content among peatland types was not discriminated by the biophysical and physical variables considered in this study. This study has shown that peat accumulation basin heterogeneity and peatland geometric shape influenced peat C, N, and P stocks at the regional scale.