Peatland GHG release via the aquatic pathway: findings from the 'UK Carbon Catchments' Network

Peatlands represent major stores of terrestrial carbon; their drainage waters are highly and consistently supersaturated in both CO₂ and CH₄, and release significant amounts of GHG’s to the atmosphere. The ‘UK Carbon Catchments’ are a network of 4 peatland sites where we aim to quantify individual carbon budgets by measuring and combining various flux terms, including aquatic export and evasion. Here we present a complete 2-year GHG budget from ‘Auchencorth Moss’, one of the Scottish sites, alongside preliminary results from the remaining 3 catchments. The results show losses via aquatic evasion equating to 12% of the net ecosystem exchange CO₂-equivalent uptake. We also present recent research from the ‘Moor House’ catchment which indicates an additional aquatic flux pathway which has yet to be quantified. Natural soil pipes in peatland systems not only contribute significantly to total stream discharge, but can transport very high concentrations of GHGs (<18.9 mg CO₂-C L^-1; <700 &micro;g CH₄-C L^-1) to the peat surface. We present evidence which suggests pipe outlets may represent a further aquatic hotspot for GHG release from peat catchments.