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Project title

Analysis of terrestrial methane emissions and impacts of peatland restoration on Ireland’s Carbon Cycle

Primary Funding Agency

Environmental Protection Agency

Co-Funding Organisation(s)

n/a

Lead Organisation

University of Limerick (UL)

Lead Applicant

Ken Byrne

Project Abstract

Worldwide, peatlands occupy about 3% of the land area and store 25% of the global C stock. In natural conditions, undrained peatlands are C sinks; however, indirect and direct human induced activities disturbed C balance of these ecosystems via drainage, resulting in 0.5-1.0 Gt C emissions, accounting for 5-10% of annual anthropogenic CO2 emissions. In Ireland, peatlands occupy 20% (1.46 m ha) of the landscape and have been subjected to human impact for centuries, much of it deeply imbedded in its culture and identity. The utilisation of these drained peatlands for agriculture, forestry and peat extraction has transformed the C balance, from sinks to sources. According to the National Inventory Report, 8.3 mt of CO2-eq. yr-1 emitted from 330,000 ha of drained grassland on peat soils. A further 1.5 mt of CO2-eq. yr-1 emitted from areas used for peat extraction. While forest plantations on peat soils reported to be net C sinks, recent work suggest that forest peat soils in Ireland are net C sources. However, drained peatlands worldwide are being increasingly rewetted for reducing GHG emissions, increasing C sequestration and enhancing ecosystem services such as improved water quality and biodiversity. Despite this, studies of rewetting in Ireland are limited and there is a need to quantify CO2 and CH4 emissions on drained but later rewetted peatlands, thus providing scientifically robust, national specific data quantifying rewetting and GHG benefits. In drained Irish peatlands, the top 2-4 m of peat layer i.e. the acrotelm and some part of bottom peat layer i.e. catotelm have been removed for horticulture and energy and heating purposes. These catotelm layers, often having lower peat profiles, and increasing contact with sub-peat mineral soils. Upon removal of the top peat layers, the acidic nutrient poor systems have fen like conditions i.e. especially vegetation growth happening due to groundwater inputs e.g. Typha species growing in ditches. However, most of the scientific studies on drained but later rewetted peatlands have always quantified CO2 emissions and C sequestration. There are significant knowledge gaps existing regarding methane (CH4) emissions in drained but later rewetted industrial peatlands. There are not many studies in Ireland, quantifying CH4 emissions from drained but later rewetted peatlands through time. This study hypothesizes that quantifying CH4 emissions is very important from drained vegetated areas having Typha or Phragmites australis growth, open flooded water areas, drained but later rewetted vegetated areas having fen like vegetation and a control area having sphagnum moss growth. This study will utilize field scale monitoring and process based computer modelling for quantifying CH4 emissions from two Irish peatlands i.e. All Saints Bog and Cavemount Bog Co. Offaly, drained decades ago, but recently rewetted. The field scale monitoring will consists of quantifying daily groundwater table depths, peat moistures, peat and water temperatures, redox, pH in water and peat and measuring CH4 emissions using chamber method and LICOR analysers. One of the process based models like Wetland-DNDC or BASGRA-BCG and Peatland-VU model utilized for quantifying CO2 and CH4 emissions using field collected data.

Grant Approved

�290,597.22

Research Hub

Climate Change

Research Theme

n/a

Start Date

01/04/2022

Initial Projected Completion Date

01/04/2025