HYDROGEOCHEMICAL RELATIONSHIPS IN RIVERS DRAINING PEATLANDS IN NORTHWEST IRELAND

Peatlands are wetland ecosystems with high water tables and large accumulations of organic matter. Globally, these ecosystems store ~30% of soil carbon but are threatened by anthropogenic and climate fueled degradation. In many locations peatlands have been converted for other land uses, but the country of Ireland remains covered by ~15% peatland by area. The integrity of the Irish peatlands varies, as many are degraded from extraction practices and drainage. Physical alterations to peatlands can result in chemical and hydrologic changes. Our analysis of Irish EPA and Public Works datasets from 2007-2021 investigated the hydrological and biogeochemical trends in streams draining minimally disturbed peatlands in northwest Ireland. We account for differences in catchment land cover and geology. The concentrations of NH₄, Cl, pH, conductivity, dissolved O₂, NO₂, NO₃, and PO₄ were compared across sixteen streams that drain peatland terrains. All catchments showed inverse relationships of discharge with pH, conductivity, and Cl. The Cl concentrations ranged from below 0.05 mg/l to over 2000 mg/l, showing seasonal fluctuations and variation among catchments. Nutrient concentrations were consistently low in minimally disturbed peatland catchments. For example, NO₃ and NO₂ concentrations were often less than 0.2 mg/l and .005 mg/l respectively. However, a greater range of N species was observed in catchments with greater diversity of land use. These analyses provide a comprehensive understanding of the biogeochemical and hydrological relationships which can be used as a baseline for restoration and to examine the impacts of peatland degradation.