Impacts on Water Quality at a Newly Opened and Extracted Peatland: Influence of Internal Processes and Hydrological Connectivity in Horticultural Peat Harvesting
Bibliographic record
Abstract
Horticultural peat harvesting continues to expand in Canada, yet the impact to downstream water quality during the initial stages of peatland opening and peat extraction are poorly understood. Major changes can occur to the hydrology and internal processes within a peatland during the transition to a drained, extracted, peat field that can influence the availability and export of nutrients. In addition to changes occurring within the harvested field, drainage ditch composition and beaver (Castor canadensis) dams can further modify the water quality exported to downstream ecosystems. The objective of this study was to investigate changes to the in-field processes and hydrological connectivity that may influence the outflow water quality during the understudied period when a peatland is opened and initially extracted in the continental Boreal Forest in Alberta, Canada. Water levels, volumetric flow, depth of ice, and aeration depth were measured along with water chemistry (electrical conductivity (EC), major ions, pH, and nutrients (dissolved and particulate nitrogen (N), phosphorus (P), and carbon (C))) in surface water and groundwater in natural and harvested peat fields, and at the outflows of the peatland complex. Sampling was initiated in the fall of 2018, prior to peatland disturbance, and continued monthly from March through October in 2019 and 2021, capturing the perimeter ditching, vegetation mulching, internal ditching, and peat extraction. In situ ion availability was measured in surface peat layers, alongside surface and below ground temperature, soil moisture, and peat aeration in 2021. Perimeter ditching had little impact on the peat field hydrology; however, ditching increased the catchment contributing area and magnitude of flow to the outflow and extended the flow duration throughout the year compared to the reference. Mulching the vegetation increased water levels, surface temperatures, and initial concentrations of total dissolved N and P in porewaters within the harvested peat field, although N and P concentrations were not sustained at peak levels. Internal ditching and ongoing extraction decreased water levels below 100 cm, but soil moisture remained high and aeration was shallow. Nutrient concentrations in the harvested field were elevated relative to the reference, likely due to decomposition. Internal ditches did not consistently mirror the harvested field; higher nutrient concentrations were common and water was sourced from precipitation, surface, and deep peat porewaters in variable proportions throughout the year. Compared to natural peatland areas, harvesting activities greatly decreased peat water storage capacity, encouraged ice formation, and increased spring runoff in a landscape dominated by summer runoff. Transport of high stores of nutrients in the harvested field and internal ditches was dependent on hydrological connectivity that varied both seasonally and interannually. Thus, nutrient concentrations were often poor indicators of mass discharge and leaching risk. When ditches reached underlying mineral sediments, EC, pH, and P concentrations in outflow waters differed drastically relative to reference and harvested peatland porewaters, and drainage ditches acted as a source of predominantly mineral sediments. Waters exiting the main outflow ditch into the downstream outflow swamp had higher P and TSS concentrations, but similar N and DOC concentrations relative to an adjacent reference outflow swamp. Increased flow encouraged beavers to establish a dam at the harvesting operation outflow. Downstream of the beaver dam, ammonium and dissolved P concentrations rose above peat field outflow levels, but sediment concentrations were reduced. Although internal processes increased nutrient availability in the harvested fields, this study shows that hydrological connectivity, ditch substrate, and presence of beaver are key players governing the water quality exported downstream.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".