Reviews and syntheses: Greenhouse gas emissions from drained organic forest soils – synthesizing data for site-specific emission factors for boreal and cool temperate regions

We compiled published peer-reviewed CO2, CH4, and N2O data on managed drained organic forest soils in boreal and temperate zones to revisit the current Tier 1 default emission factors (EFs) provided in the IPCC (2014) Wetlands Supplement: to see whether their uncertainty may be reduced; to evaluate possibilities for breaking the broad categories used for the IPCC EFs into more site-type-specific ones; and to inspect the potential relevance of a number of environmental variables for predicting the annual soil greenhouse gas (GHG) balances, on which the EFs are based. Despite a considerable number of publications applicable for compiling EFs being added, only modest changes were found compared to the Tier 1 default EFs. However, the more specific site type categories generated in this study showed narrower confidence intervals compared to the default categories. Overall, the highest CO2 EFs were found for temperate afforested agricultural lands and boreal forestry-drained sites with very low tree stand productivity. The highest CH4 EFs in turn prevailed in boreal nutrient-poor forests with very low tree stand productivity and temperate forests irrespective of nutrient status, while the EFs for afforested sites were low or showed a sink function. The highest N2O EFs were found for afforested agricultural lands and forestry-drained nutrient-rich sites. The occasional wide confidence intervals could be mainly explained by single or a few highly deviating estimates rather than the broadness of the categories applied. Our EFs for the novel categories were further supported by the statistical models connecting the annual soil GHG balances to site-specific soil nutrient status indicators, tree stand characteristics, and temperature-associated weather and climate variables. The results of this synthesis have important implications for EF revisions and national emission reporting, e.g. by the use of different categories for afforested sites and forestry-drained sites, and more specific site productivity categories based on timber production potential

Greenhouse gas emissions from rewetted extracted peatlands in Sweden

Peat extraction for horticultural purposes and energy production has a long tradition in Northern Europe. Related drainage activities directly affect the greenhouse gas (GHG) balance due to oxidative peat decomposition and denitrification, with concomitant emissions of carbon dioxide (CO₂) and nitrous oxide (N₂O). Rewetting, i.e. raising of the water table, is one after-use and restoration objective. Rewetting transforms an extracted peatland with aerobic soil conditions into a wetland with prevailing anaerobic conditions and can thus create suitable conditions for peat-forming plants, which could restore carbon (C) storage functions. Studies on GHG emissions from extracted peatlands after rewetting are limited. In general, peatland rewetting decreases emissions of CO₂ and N₂O, while methane (CH₄) emissions may increase. More data are needed on GHG emissions from extracted peatlands over longer periods after rewetting and from corresponding studies about constructed water bodies and their vegetated littoral zones, which have been identified as high CH₄ emitters. Studies were investigated how typical peatland ecotopes and vegetation communities created after rewetting affected CO₂, CH₄ and N₂O emissions. Specific objectives were to determine the relationships between GHG emission fluxes and water conditions, soil/water temperature and vegetation cover. GHG emission fluxes were measured in two rewetted extracted peatlands in Sweden using manual opaque and automated transparent chambers for discontinuous and continuous measurements, respectively. The overall climate impact of CH₄ emissions from the study areas did in general not exceed the impact of soil and plant respiration and neither the net CO₂ flux during summer. But, GHG emissions could vary between years and sites can shift from sinks to sources. In regards to management of extracted peatlands, the construction of shallow lakes showed great potential for lowering GHG fluxes to the atmosphere. With continuous measurements a derivation of long-term gas balances can be achieved and short-term changes in environmental conditions influencing GHG exchanges can be detected more effectively as with discontinuous measurements, such as by vial sampling. But still, a correct indication of all GHG fluxes, e.g. for GHG upscaling purposes or national emission inventories, is strongly based on the correct estimation of all C fluxes including ebullition

Setting-aside cropland did not reduce greenhouse gas emissions from a drained peat soil in Sweden

In the process of their formation, northern peatlands were accumulating vast amounts of carbon (C). When drained for agricultural use, a large proportion of that C is oxidized and emitted as carbon dioxide (CO2), turning those peatlands to strong CO2 emitters. As a mitigation option, setting-aside farmland on drained peat is being incentivized by policies, but recent evidence casts doubt on these policies' efficiency for greenhouse gas (GHG) emission mitigation. To investigate the effects of setting-aside farmland on GHG fluxes from a Swedish peatland, we measured CO2, nitrous oxide (N2O), and methane (CH4) fluxes on two adjacent sites under contrasting management. The cultivated (CL) site was used for cereal production (wheat or barley) and the set-aside (SA) site was under permanent grassland. Carbon dioxide fluxes were measured from 2013 to 2019 using the eddy covariance (EC) method. Additionally, CO2, N2O, and CH4 fluxes were measured during the growing seasons of 2018-2020, using transparent and opaque chambers on vegetated plots and on bare peat. The cumulative CO2 fluxes measured by EC over the measurement period were 0.97 (+/- 0.05) and 2.09 (+/- 0.17) kg m-2 with annual average losses of 0.16 and 0.41 kg CO2 m-2 yr-1 for the CL and SA site, respectively. Thus, the SA site acted as a stronger CO2 source than the CL site. Both sites' contribution to global warming, calculated on basis of the chamber measurements, was dominated by CO2. The contribution of the SA site was higher than that of the CL site. Nitrous oxide emissions were low at both sites with higher emissions from the CL site for transparent measurements and measurements on bare peat. Whereas, CH4 uptake was highest on the SA grassland. Thus, on the basis of our study, we found no evidence that setting-aside farmland on shallow drained peat soils will reduce GHG emissions or even turn the peatland into a C sink

Library Monthly - February 2015

Inaugural issue of Library Monthly, the Lynn University Library monthly newsletter. In this issue: Amy\u27s Annotations iBooks Catalog Expandinghttps://spiral.lynn.edu/libpubs/1000/thumbnail.jp

Distribution of the two forms of Plasmodium falciparum erythrocyte binding antigen-175 (eba-175) gene in Lao PDR

BACKGROUND: The erythrocyte binding antigen 175 (EBA-175) is a 175 kDa antigen of Plasmodium falciparum and plays a major role in erythrocyte recognition by the parasite. The antigen is also supposed to be partly responsible for the invasion of erythrocytes by merozoites. EBA-175 has been sequenced from the FCR-3 and CAMP strains of P. falciparum. The sequences were identical in most parts of the gene. Differences were apparent in a 423 bp segment in the FCR-3 strain, the F-Fragment, that is not found in the CAMP-strain and a 342 bp segment, the C-Fragment, which is present in the CAMP-strain but not in the FCR-3-strain. The aim of this study was to assess the distribution of the two EBA-175-alleles in the Lao PDR. MATERIALS & METHODS: Altogether, 240 blood-samples were collected in two areas of the country: Attapeu in the south and Lung Namtha in the north. Subsequently, the material was scanned for the F-and C-fragments. RESULTS: In the whole study population, 52% carried the F-fragment, and 41% the C-fragment while seven percent of the patients were infected with at least two parasite strains and showed both alleles. CONCLUSION: Distribution of the alleles showed significant differences between the north and the south province. Reasons for this include possible importation of different parasite strains from neighbouring countries