Summary
Northern peatlands disproportionately contribute large amounts of dissolved organic matter (DOM) to inland waters. Disturbance regimes are rapidly changing in northern peatlands, altering the hydrology and biogeochemistry of peatlands and potentially altering the magnitude and chemical composition of exported DOM. DOM consists of complex organic molecules that contain carbon (C), nitrogen (N), and phosphorus (P). Dissolved organic C (DOC), N, and P are essential for ecosystem function, but an overabundance of these solutes can cause water brownification and eutrophication. To investigate the effects of peat harvesting on water quality, we collected stream water samples during the spring, summer, and fall from 55 subwatersheds near industrial peat extraction sites in Seba Beach, Alberta, Canada. We found that DOC concentrations on average in disturbed peat catchments was 83.36 mg/L, which was 32% higher than pristine peatlands and 93% higher than other land use types. For N, ammonium was the major driver of elevated N concentrations, and we observed ammonium concentrations upwards of 4.54 mg/L in disturbed peatland catchments which is almost double local water guidelines for dissolved inorganic nitrogen. P showed little response to peat harvesting, suggesting that most of the phosphorous in disturbed peatlands was removed during harvesting. However, total P concentrations throughout the watersheds were double local water quality guidelines on average. Together, with multivariate analysis, these results suggest peat harvesting increases DOC and N export to downstream ecosystems. |
Fig. 1 Aerial view of the corner of a harvested peatland and the surrounding pristine peatlands near Seba Beach, Alberta.
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