Knowledge Bank

Peatlands are wetland ecosystems with high water tables and large accumulations of organic matter. Globally, peatlands store ~30% of soil carbon but are threatened by anthropogenic and climate fueled degradation. Peatlands are often converted for other land uses, but the Republic of Ireland remains covered by ~15% peatland by area. The integrity of Irish peatlands varies, as many are subjected to extraction practices and drainage. These physical alterations can affect the chemistry and hydrology by altered base flow and increased transport of ions. Our analysis of Irish EPA and OPW datasets from 2007–2021 investigated the hydrogeochemistry of streams draining nearly undisturbed peatlands in northwest Ireland. Hydrologically, the maximum, mean, and median daily annual discharge for 1980–2020 increased or remained constant for sites. The minimum daily annual discharge remained constant for sites with high percentages of peatland by area. Disturbed sites with less peatland by area showed changing discharge over time. Historical data of major ions and DOC were augmented with samples from September 2023 of streams in Counties Mayo, Galway, and Sligo. Streams primarily draining peatland historically showed limited PO4 and N levels. The September 2023 samples showed an inverse and linear relationship between N vs. peatland and N vs. pastureland area respectively. The landcover and bedrock type correlated well with F, SO4, K, Mg, Ca, DOC, N and F, Cl, SO4, Na, K, Mg, Ca, N respectively. Our analyses provide a comprehensive understanding of the hydrogeochemical relationships which can be used as a baseline for any future restoration.