Beneath the Blanket: Towards a better understanding of stream ecology in blanket peat covered catchments.

Water quality forms an essential abiotic factor underpinning the functioning and status of aquatic ecosystems. Despite dominating uplands across of much of North western Europe, the inter relationship between water draining Atlantic blanket bog ecosystems and aquatic ecological receptors remains poorly defined. In Ireland many blanket bog covered catchments have hosted high status streams which, over the past decade, experienced significant degradation and are now in need of programmes of measures to comply with Water Framework Directive Legislation. Defining restoration goals requires an improved understanding of stream hydrology and the water quality regime draining intact peatlands if realistic targets are to be established. 
In an attempt to address this shortcoming, the EPA study “Quantification of Blanket Bog Ecosystem Services to Water (QUBBES)” aimed to evaluate abiotic conditions supporting aquatic ecosystems in relatively undisturbed blanket peat-covered catchments. Following a survey of 341 the most intact catchments across the island of Ireland, of which all were discovered to display some physical damage from anthropogenic activity, QUBBES researchers selected three sites, considered among the least damaged, to characterise the flow regime and water quality of their draining streams. The sites lie along a climatic gradient, locally containing significant thicknesses of peat (0m to >5m) with similar (peat) groundwater quality, yet are underlain by geochemically distinct inorganic subsoil and bedrock substrates. 
Runoff monitoring over a two-year period revealed flashy flow regimes in all three catchments, while high frequency water quality monitoring showed the streams contained acidic, nutrient-poor acidic waters, comparable to those encountered in bog groundwater, during energetic high flow hydrological events. This contrasted with water quality observed in samples collected during lower (base) flow. Under these conditions water quality in each catchment differed strongly from peak flow, as well as from one catchment to another. Quality in the catchment underlain by limestone bedrock (, overlain by a glacial till containing erratic crystalline rock,) was dominated by alkaline, calcium carbonate rich waters, while relative abundances in water samples collected from a stream draining an area underlain by sandstone and shale, overlain by locally derived till, were more acidic and dominated by silica; samples from the stream draining a catchment underlain by basalt bedrock and basalt-rich till were dominated by calcium and silica-rich alkaline waters. 
Study findings revealed the dominance of peat substrate-derived groundwater inputs to base flow and can help explain the biological variability of upland streams in areas covered by blanket peats, containing similar groundwater. Furthermore, findings suggest that aquatic biological metrics for peat covered catchments should give greater consideration to the significance of substrate composition.