Assessing the impact of peatland restoration on freshwater ecosystems

Decades of degradation have turned the UK’s peatlands from sinks to sources of organic carbon, with adverse consequences for adjacent freshwater ecosystems. However, restoration efforts which broadly aim to raise the water table and re-establish vegetation are accelerating. Restoration not only slows erosion and thu sparticle export to rivers and streams, it also fundamentally alters the soil processes which dictate thechemical composition of the waters exported. Outflow water composition is governed by a dynamic array of biological, hydrological and geochemical processes occurring in the peat itself, thus the results can be highlysite dependent and difficult to predict. Such unforeseen interactions could limit the success of thesemeasures in safe-guarding nearby freshwater ecosystems. Thus it is of critical importance to quantify the effect restoration has on the biogeochemistry of the peatland itself in order to predict its effect on surrounding freshwater ecosystems.We are seeking a highly motivated PhD student to join our multi-disciplinary team and work alongside the Brecon Beacons National Park Authority to: 1) Determine how soil biogeochemistry changes during peatland restoration2) Identify how these changes impact the freshwater microbiota in adjacent rivers and streams The student will conduct studies at two peatlands in the Brecon Beacons, Waun Fach and Waun Fignen Felin, which have differing lithology, restoration status and specific water quality issues. Porewater depth profiles will be collected across areas of undisturbed, degraded and restored peat throughout the year, tracing the flow of water into surrounding rivers and streams. Porewater will be geochemically characterized (pH,nutrient fractions including the dissolved and particulate organic fractions, DOC, trace elements, iron redoxstate) and compared to solid phase analyses of peat cores collected in the same area (geochemistry,mineralogy and microbial community structure). Stream water samples will also be analysed at increasingdistances from the source to determine the extent to which processes in the streams themselves influencenutrient fractionation and organic matter content. Organic matter processing within the streams and the impact of these fluxes on freshwater microbiota will be further simulated in the lab using incubations of outflow water, incorporating both microbial and abiotic processes.