• Energy Research
• 15. Life on land close
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• Russian Academy of Sciences close

Abstract. Regional land carbon budgets provide insights on the spatial distribution of the land uptake of atmospheric carbon dioxide, and can be used to evaluate carbon cycle models and to define baselines for land-based additional mitigation efforts. The scientific community has been involved in providing observation-based estimates of regional carbon budgets either by downscaling atmospheric CO2 observations into surface fluxes with atmospheric inversions, by using inventories of carbon stock changes in terrestrial ecosystems, by upscaling local field observations such as flux towers with gridded climate and remote sensing fields or by integrating data-driven or process-oriented terrestrial carbon cycle models. The first coordinated attempt to collect regional carbon budgets for nine regions covering the entire globe in the RECCAP-1 project has delivered estimates for the decade 2000–2009, but these budgets were not comparable between regions, due to different definitions and component fluxes reported or omitted. The recent recognition of lateral fluxes of carbon by human activities and rivers, that connect CO2 uptake in one area with its release in another also requires better definition and protocols to reach harmonized regional budgets that can be summed up to the globe and compared with the atmospheric CO2 growth rate and inversion results. In this study, for the international initiative RECCAP-2 coordinated by the Global Carbon Project, which aims as an update of regional carbon budgets over the last two decades based on observations, for 10 regions covering the globe, with a better harmonization that the precursor project, we provide recommendations for using atmospheric inversions results to match bottom-up carbon accounting and models, and we define the different component fluxes of the net land atmosphere carbon exchange that should be reported by each research group in charge of each region. Special attention is given to lateral fluxes, inland water fluxes and land use fluxes.

The aim of the study - identification of factors that ensure the vital activity of indigenous small-numbered peoples of the North in the Arctic, as well as the analysis of their impact on the preservation and development of the ethnic group. Identifying problems and assessing the prospects for the development of indigenous people consists of 3 stages: analysis of foreign and domestic sources, the results of scientific research teams; systematization of statistical data, including information on the dynamics of the development of indigenous people (number, employment in traditional activities); the impact assessing of legal, economic and social factors on the preservation and development of indigenous people. A comprehensive analysis of a wide range of legal, economic and social problems of ensuring the traditional life of indigenous people within the Arctic zone of the Russian Federation (AZRF) has shown the need to improve legislative, financial and managerial actions to preserve them as a specific community, adapted to the extremely severe conditions of permanent residence beyond the Arctic Circle and as a unique phenogenotype, whose activity is closely conjugated with the environmental state of the macroregion and in fact is entirely dependent on it. The exclusive role of indigenous peoples in preserving the natural complexes of the Arctic in the 21st century for future generations was emphasized. Under the conditions of proliferation of technogenic and anthropogenic burden on the natural complexes of the macroregion, associated with the intensive development of fuel and power resources, deposits of rare and precious metals, development of coastal transport infrastructure and a multiple increase in the population in the Russian Arctic with a creation of "stronghold areas" the threat of the indigenous peoples' disappearance appeared (Enets - about 200 people remain and less than 100 people - the Votes). Under the conditions of a large-scale, integral impact of man-made, anthropogenic and climatic factors on indigenous communities in the Arctic, their life environment and traditional management the need for urgent adoption of a complex of specific and targeted legal, economic and social measures aimed at ensuring and preserving their livelihoods is obvious.

Advances in the phenology of organisms are often attributed to climate change, but alternatively, may reflect a publication bias towards advances and may be caused by environmental factors unrelated to climate change. Both factors are investigated using the breeding dates of 25 long-term studied populations of Ficedula flycatchers across Europe. Trends in spring temperature varied markedly between study sites, and across populations the advancement of laying date was stronger in areas where the spring temperatures increased more, giving support to the theory that climate change causally affects breeding date advancement.

The effect of intra- and interspecific competition on the spatial distribution of the biomass and mortmass of woody plant roots in mixed tree stands has been studied. It has been found that the mass of roots in the samples from tree pairs of different species is higher than in the samples from monospecific pairs. Species-specific differences in the vertical distribution of roots and the effect of intra- and interspecific competition on the spatial structure of biomass have been shown. It has been noted that the proportion of dead roots increases almost linearly with depth.

Abstract. This paper aims to assess the spatial variability in the response of CO2 exchange to irradiance across the Arctic tundra during peak season using light response curve (LRC) parameters. This investigation allows us to better understand the future response of Arctic tundra under climatic change. Peak season data were collected during different years (between 1998 and 2010) using the micrometeorological eddy covariance technique from 12 circumpolar Arctic tundra sites, in the range of 64–74° N. The LRCs were generated for 14 days with peak net ecosystem exchange (NEE) using an NEE–irradiance model. Parameters from LRCs represent site-specific traits and characteristics describing the following: (a) NEE at light saturation (Fcsat), (b) dark respiration (Rd), (c) light use efficiency (α), (d) NEE when light is at 1000 μmol m−2 s−1 (Fc1000), (e) potential photosynthesis at light saturation (Psat) and (f) the light compensation point (LCP). Parameterization of LRCs was successful in predicting CO2 flux dynamics across the Arctic tundra. We did not find any trends in LRC parameters across the whole Arctic tundra but there were indications for temperature and latitudinal differences within sub-regions like Russia and Greenland. Together, leaf area index (LAI) and July temperature had a high explanatory power of the variance in assimilation parameters (Fcsat, Fc1000 and Psat, thus illustrating the potential for upscaling CO2 exchange for the whole Arctic tundra. Dark respiration was more variable and less correlated to environmental drivers than were assimilation parameters. This indicates the inherent need to include other parameters such as nutrient availability, substrate quantity and quality in flux monitoring activities.

AbstractAgeratum conyzoides, an herb found throughout the year, is generally considered as a weed: it causes reduction in soil productivity and leads to health hazards for cattle and humans. However, its biomass can easily represent a cost‐effective source, which can be used for lignocellulosic biofuel production. The conversion of lignocellulosic biomass to ethanol has drawn much attention in recent times due to abundance of biomass. In the present study, the cellulose and hemicellulose biomass of the leaf and stem of A. conyzoides was converted to sugars using acid hydrolysis.146.01 ± 02 mg/g of fermentable sugar was obtained from A. conyzoides. The maximum ethanol concentration 11.89 g/L was obtained after 7 days. Scanning electron microscopy was used to characterize the surface morphology after acid hydrolysis of biomass. In the current study, the residues of acid hydrolysis and fermented wastewater was used for biogas production through anaerobic digestion. The yield of biogas from the residues of acid hydrolysis and fermented wastewater was 204 L kg−1VS. The results obtained indicate that A. conyzoides may be considered as a promising feedstock for bioethanol and biogas production.