Upland Peat Mesocosm Experiments
Aim
Compared with lowland peatlands, upland peatlands have different ecology and management practices. They are often home to protected species and can be challenging to access if they are remote. A series of feasibility studies as mesocosm experiments were designed to screen which peatland restoration methods could be applied in upland settings in ways that have a low environmental impact.
Solutions tested
The mesocosm experiments used intact soil cores collected from upland field sites in the South Pennines. These core samples were placed into outdoor water-controlled mesocosm bins, each with pre-drilled outlets to maintain precise water table levels.
- Raising the water tables – Using intact peat cores in controlled mesocosm bins, researchers tested higher water tables (at around 15cm below the surface) versus lower water tables.
- Can biochar be applied to upland peat? – Upland peatlands can be challenging to access, and there is debate around whether biochar should be applied to the soil. Different ways to apply biochar were tested to explore both the ecological feasibility and their effect on the peatland. This included surface application and adding biochar to Sphagnum moss plugs and planting these directly into the soil.
Observations to-date [end-2025]:
1. Higher water tables and biochar reduce emissions
Raising the water table limits oxygen, which slows down the decomposition of organic matter that releases carbon dioxide ( CO2). Biochar alters the soil microbial community, which can reduce the activity of enzymes that break down organic material.
- Highest carbon preservation: Plots treated with biochar made from Juncus effusus lost only 7.9 tons of CO₂-equivalent per hectare per year, which is less carbon loss than other treatments tested. The most effective approach for peatland restoration was found to be a combination of higher water tables, biochar treatments, and adding iron sulphate
2. Microbial and enzyme effects
The combination treatment suppressed enzyme activity (e.g., β-glucosidase) and methanogen activity, slowing peat decomposition. Adding iron sulphate forms an “iron gate” that binds carbon, stabilises soil organic matter, and reduces methane emissions because different species of bacteria and fungi are encouraged to grow in the peat.
The South Pennines mesocosm experiments have been running for three years and are now complete. Data analysis is under way and will be written up and published in late-2026.
What is a mesocosm experiment?
Mesocosms are small scale experiments on soil collected from a field site. The soil is collected as intact core samples and then enclosed in a container. These experiments can be used to examine how soil, plants and microbes respond to different conditions by controlling specific factors, like raising the water table, changing nutrient levels, or introducing pollutants. This can be difficult to achieve in a natural, open field setting, and so mesocosm experiments strike a balance between field experiments and highly controlled lab experiments.
Publications
Rewetting alongside biochar and sulphate addition mitigates greenhouse gas emissions and retain carbon in degrade upland peatlands. Peduruhewa H. Jeewani, Robert W. Brown, Chris D. Evans, Jack Cook, Benjamin P. Roberts, Mariecia D. Fraser, David R. Chadwick, Davey L. Jones. Soil Biology and Biochemistry. Volume 207, August (2025). https://doi.org/10.1016/j.soilbio.2025.109814