Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

Abstract

Abstract. Peatland restoration may provide a potential afteruse option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (Res H ) and low (Res L ) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in Res H relative to Res L . Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in Res L compared to Res H . However, the means of the measured net ecosystem CO 2 exchanges (NEE) were not significantly different between Res H and Res L . Similarly, no significant differences were observed in the respective means of CH 4 and N 2 O exchanges. In comparison to the two restored sites, greater net CO 2 , similar CH 4 and greater N 2 O emissions occurred in BP. On the annual scale, Res H , Res L and BP were C sources of 111, 103 and 268 g C m −2 yr −1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO 2 eq ha −1 yr −1 , respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in Res H and Res L were considerably lower than in BP due to the large reduction in CO 2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

Methane and Nitrous Oxide Emission Fluxes Along Water Level Gradients in Littoral Zones of Constructed Surface Water Bodies in a Rewetted Extracted Peatland in Sweden

“…We are aware that we might have missed "hot moments" [94] of N 2 O fluxes given our sampling campaign and that the available N might have been taken up by the vegetation, thus contributing to the low N 2 O fluxes observed [40,96].…”

High-Temperature Hay Biochar Application into Soil Increases N2O Fluxes

“…Gas samples were collected during one hour in 20 min intervals (0, 20, 40, 60 min) into 12 mL pre-evacuated (0.04 mbar) bottles [55].…”

Afforestation of cutaway peatlands: effect of wood ash on biomass formation and carbon balance

“…Teada on, et kliimasoojenemist põhjustava süsihappegaasi kontsentratsiooni suurenemist on mõjutanud olulised muutused maakasutuses (freestehnoloogial turba kaevandamine, soode kuivendamine metsakasvatamise ja põlluharimise eesmärgil jne) (Picken, 2006;Alm et al, 2007;Salm et al, 2012) ning süsiniku kadu kasvab globaalsel tasemel ka tulevikus (Waddington et al, 2002). Looduslikest soodest emiteerub kasvuhoonegaasidest peamiselt metaani (CH 4 ) ja naerugaasi ehk dilämmastikoksiidi (N 2 O) (Waddington & Roulet, 2000;Mander et al, 2010;Järveoja et al, 2016), ammendatud jääksoodest turba mineraliseerumise tõttu domineerivalt süsihappegaasi (CO 2 ) Yli-Petäys et al, 2007).…”

“…Täheldatud on suuremat CO 2 emissiooni kõrgema veetasemega ja intensiivsemalt taimestunud aladelt Anderson, 2010). Kasvuhoonegaaside emissiooni oluliseks mõjutajaks ammendatud freesturbaväljadel on peale veetaseme ka selle kõikumine vegetatsiooniperioodil (Järveoja et al, 2016;Karki et al, 2016). Metsastatud jääksoodes on olulisemateks süsiniku bilanssi mõjutavateks faktoriteks puistute produktiivsus ja jääkturba lagunemisaste (Alm et al, 2007;Huotari et al, 2009).…”