Restaurering av myr. Potensialet for karbonlagring og reduksjon av klimagassutslipp

I denne rapporten har vi undersøkt i hvilken grad restaurering av myr kan bidra til ny karbonlagring og samtidig reduserte klimagassutslipp. Et litteraturstudium viser at drenert myr er en langt større kilde til CO2-utslipp enn både naturlig og restaurert myr. Årsaken til den høye CO2-emisjonen i drenert myr er lavere grunnvannstand, tilgang på oksygen og økt jordrespirasjon. Høy grunnvannstand i naturlig og restaurert myr motvirker jordrespirasjonen og bidrar til lagring av karbon i jorda. Restaurering av myr vil derfor som regel redusere karbontapet, og kan, avhengig av forholdene på stedet, gjenskape området til et karbonsluk

Controlled infrared heating of an artic meadow: challenge in the vegetation establishment stage

Background: Global warming is going to affect both agricultural production and carbon storage in soil worldwide. Given the complexity of the soil-plant-atmosphere continuum, in situ experiments of climate warming are necessary to predict responses of plants and emissions of greenhouse gases (GHG) from soils. Arrays of infrared (IR) heaters have been successfully applied in temperate and tropical agro-ecosystems to produce uniform and large increases in canopy surface temperature across research plots. Because this method had not yet been tested in the Arctic where consequences of global warming on GHG emission are expected to be largest, the objective of this work was to test hexagonal arrays of IR heaters to simulate a homogenous 3 °C warming of the surface, i.e. canopy and visible bare soil, of five 10.5-m2 plots in an Arctic meadow of northern Norway. Results: Our results show that the IR warming setup was able to simulate quite accurately the target + 3 °C, thereby enabling us to simulate the extension of the growing season. Meadow yield increased under warming but only through the lengthening of the growing season. Our research also suggests that, when investigating agricultural systems on the Arctic, it is important to start the warming after the vegetation is established,. Indeed, differential emergence of meadow plants impaired the homogeneity of the warming with patches of bare soil being up to 9.5 °C warmer than patches of vegetation. This created a pattern of soil crusting, which further induced spatial heterogeneity of the vegetation. However, in the Arctic these conditions are rather rare as the soil exposed by snow melt is often covered by a layer of senescent vegetation which shelters the soil from direct radiation. Conclusions: Consistent continuous warming can be obtained on average with IR systems in an Arctic meadow, but homogenous spatial distribution requires that the warming must start after canopy closure

Controlled infrared heating of an artic meadow: challenge in the vegetation establishment stage

Background: Global warming is going to affect both agricultural production and carbon storage in soil worldwide. Given the complexity of the soil-plant-atmosphere continuum, in situ experiments of climate warming are necessary to predict responses of plants and emissions of greenhouse gases (GHG) from soils. Arrays of infrared (IR) heaters have been successfully applied in temperate and tropical agro-ecosystems to produce uniform and large increases in canopy surface temperature across research plots. Because this method had not yet been tested in the Arctic where consequences of global warming on GHG emission are expected to be largest, the objective of this work was to test hexagonal arrays of IR heaters to simulate a homogenous 3 °C warming of the surface, i.e. canopy and visible bare soil, of five 10.5-m2 plots in an Arctic meadow of northern Norway. Results: Our results show that the IR warming setup was able to simulate quite accurately the target + 3 °C, thereby enabling us to simulate the extension of the growing season. Meadow yield increased under warming but only through the lengthening of the growing season. Our research also suggests that, when investigating agricultural systems on the Arctic, it is important to start the warming after the vegetation is established,. Indeed, differential emergence of meadow plants impaired the homogeneity of the warming with patches of bare soil being up to 9.5 °C warmer than patches of vegetation. This created a pattern of soil crusting, which further induced spatial heterogeneity of the vegetation. However, in the Arctic these conditions are rather rare as the soil exposed by snow melt is often covered by a layer of senescent vegetation which shelters the soil from direct radiation. Conclusions: Consistent continuous warming can be obtained on average with IR systems in an Arctic meadow, but homogenous spatial distribution requires that the warming must start after canopy closure

Low impact of dry conditions on the CO2 exchange of aNorthern-Norwegian blanket bog.

Northern peatlands hold large amounts of organic carbon (C) in their soils and are as such important in a climate change context. Blanket bogs, i.e. nutrient-poor peatlands restricted to maritime climates, may be extra vulnerable to global warming since they require a positive water balance to sustain their moss dominated vegetation andCsink functioning. This study presents a 4.5 year record of land– atmosphere carbon dioxide (CO2) exchange from the Andøya blanket bog in northern Norway. Compared with other peatlands, the Andøya peatland exhibited low flux rates, related to the low productivity of the dominating moss and lichen communities and the maritime settings that attenuated seasonal temperature variations. It was observed that under periods of high vapour pressure deficit, net ecosystem exchange was reduced, which was mainly caused by a decrease in gross primary production. However, no persistent effects of dry conditions on theCO2 exchange dynamics were observed, indicating that under present conditions and within the range of observed meteorological conditions the Andøya blanket bog retained its Cuptake function. Continued monitoring of these ecosystem types is essential in order to detect possible effects of a changing climate. peatland, carbon, blanket bog, eddy covariance, climate change, net ecosystem exchang

Modelling CO2 and CH4 emissions from drained peatlands with grass cultivation by the BASGRA-BGC model

Cultivated peatlands under drainage practices contribute significant carbon losses from agricultural sector in the Nordic countries. In this research, we developed the BASGRA-BGC model coupled with hydrological, soil carbon decomposition and methane modules to simulate the dynamic of water table level (WTL), carbon dioxide (CO2) and methane (CH4) emissions for cultivated peatlands. The field measurements from four experimental sites in Finland, Denmark and Norway were used to validate the predictive skills of this novel model under different WTL management practices, climatic conditions and soil properties. Compared with daily observations, the model performed well in terms of RMSE (Root Mean Square Error; 0.06–0.11 m, 1.22–2.43 gC/m2/day, and 0.002–0.330 kgC/ha/day for WTL, CO2 and CH4, respectively), NRMSE (Normalized Root Mean Square Error; 10.3–18.3%, 13.0–18.6%, 15.3–21.9%) and Pearson's r (Pearson correlation coefficient; 0.60–0.91, 0.76–0.88, 0.33–0.80). The daily/seasonal variabilities were therefore captured and the aggregated results corresponded well with annual estimations. We further provided an example on the model's potential use in improving the WTL management to mitigate CO2 and CH4 emissions while maintaining grass production. At all study sites, the simulated WTLs and carbon decomposition rates showed a significant negative correlation. Therefore, controlling WTL could effectively reduce carbon losses. However, given the highly diverse carbon decomposition rates within individual WTLs, adding indi-cators (e.g. soil moisture and peat quality) would improve our capacity to assess the effectiveness of specificmitigation practices such as WTL control and rewetting

Experimental warming and precipitation reduction affect the biomass of microbial communities in a Sphagnum peatland

Due to their unique flora, hydrology and environmental characteristics, peatlands are precious and specific habitats for microorganisms and microscopic animals. Their microbial network structure and their biomass are crucial for peatland carbon cycling, through primary production, as well as decomposition and mineralization of organic matter. Wetlands are one of the ecosystems most at risk from anthropogenic activities and climate change. Most recent scenarios of climate change for Central Europe predict an increase in air temperature and a decrease in annual precipitation. These changes may disturb the biodiversity of aquatic organisms, and the peat carbon sink. Considering the above climatic scenarios, we aimed to: i) assess the response of microbial community biomass to warming and reduced precipitation through the lens of a manipulative experiment in a peatland ecosystem ii) predict how global warming might affect microbial biodiversity on peatlands exposed to warmer temperatures and decreased precipitation conditions. Additionally, we wanted to identify ecological indicators of warming among microorganisms living in Sphagnum peatland. The result of a manipulative experiment carried out at Rzecin peatland (W Poland) suggested that the strongest reduction in microbial biomass was observed in heated plots and plots where heating was combined with a reduction of precipitation. The most pronounced changes were observed in the case of the very abundant mixotrophic testate amoeba Hyalosphenia papilio and cyanobacteria. Shifts in the Sphagnum microbial network can be used as an early warning indicator of peatland warming, especially a decrease in the biomass of important phototrophic microbes living on the Sphagnum capitula, e.g. Hyalosphenia papilio.publishedVersio

Utslippsreduksjoner i norsk jordbruk - Kunnskapsstatus og tiltaksmuligheter

Sammendrag: Denne rapporten gir en oppdatert oversikt over tiltakspotensiale for tiltak som jordbruket kan iverksette for å redusere klimagassutslipp. Det er tiltak innen dagens produksjonsystemer og struktur som er vektlagt. Det er sammenlignet med vurderinger gjort i rapporten «Landbruk og klimaendringer» fra 2016. Effekt av tiltak, gjennomføringsgrad og forutsetninger for gjennomføring til 2030 er prioritert

Utslippsreduksjoner i norsk jordbruk. Kunnskapsstatus og tiltaksmuligheter.

Sammendrag: Denne rapporten gir en oppdatert oversikt over tiltakspotensiale for tiltak som jordbruket kan iverksette for å redusere klimagassutslipp. Det er tiltak innen dagens produksjonsystemer og struktur som er vektlagt. Det er sammenlignet med vurderinger gjort i rapporten «Landbruk og klimaendringer» fra 2016. Effekt av tiltak, gjennomføringsgrad og forutsetninger for gjennomføring til 2030 er prioritert

Utslippsreduksjoner i norsk jordbruk. Kunnskapsstatus og tiltaksmuligheter.

Sammendrag: Denne rapporten gir en oppdatert oversikt over tiltakspotensiale for tiltak som jordbruket kan iverksette for å redusere klimagassutslipp. Det er tiltak innen dagens produksjonsystemer og struktur som er vektlagt. Det er sammenlignet med vurderinger gjort i rapporten «Landbruk og klimaendringer» fra 2016. Effekt av tiltak, gjennomføringsgrad og forutsetninger for gjennomføring til 2030 er prioritert.publishedVersio

Utslippsreduksjoner i norsk jordbruk. Kunnskapsstatus og tiltaksmuligheter.

Sammendrag: Denne rapporten gir en oppdatert oversikt over tiltakspotensiale for tiltak som jordbruket kan iverksette for å redusere klimagassutslipp. Det er tiltak innen dagens produksjonsystemer og struktur som er vektlagt. Det er sammenlignet med vurderinger gjort i rapporten «Landbruk og klimaendringer» fra 2016. Effekt av tiltak, gjennomføringsgrad og forutsetninger for gjennomføring til 2030 er prioritert