| 1. |
- Downing, J. A., et al.
(författare)
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Global abundance and size distribution of streams and rivers
- 2012
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Ingår i: Inland Waters. - 2044-2041 .- 2044-205X. ; 2:4, s. 229-236
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Tidskriftsartikel (refereegranskat)abstract
- To better integrate lotic ecosystems into global cycles and budgets, we provide approximations of the size-distribution and areal extent of streams and rivers. One approach we used was to employ stream network theory combined with data on stream width. We also used detailed stream networks on 2 continents to estimate the fraction of continental area occupied by streams worldwide and corrected remote sensing stream inventories for unresolved small streams. Our estimates of global fluvial area are 485 000 to 662 000 km2 and are +30–300% of published appraisals. Moderately sized rivers (orders 5–9) seem to comprise the greatest global area, with less area covered by low and high order streams, while global stream length, and therefore the riparian interface, is dominated by 1st order streams. Rivers and streams are likely to cover 0.30–0.56% of the land surface and make contributions to global processes and greenhouse gas emissions that may be +20–200% greater than those implied by previous estimates.
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| 2. |
- Abbott, Benjamin W., et al.
(författare)
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Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire : an expert assessment
- 2016
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced.
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| 3. |
- Cole, J.J., et al.
(författare)
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Plumbing the global carbon cycle : Integrating inland waters into the terrestrial carbon budget
- 2007
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Ingår i: Ecosystems (New York. Print). - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 10:1, s. 172-185
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Forskningsöversikt (refereegranskat)abstract
- Because freshwater covers such a small fraction of the Earth’s surface area, inland freshwater ecosystems (particularly lakes, rivers, and reservoirs) have rarely been considered as potentially important quantitative components of the carbon cycle at either global or regional scales. By taking published estimates of gas exchange, sediment accumulation, and carbon transport for a variety of aquatic systems, we have constructed a budget for the role of inland water ecosystems in the global carbon cycle. Our analysis conservatively estimates that inland waters annually receive, from a combination of background and anthropogenically altered sources, on the order of 1.9 Pg C y−1 from the terrestrial landscape, of which about 0.2 is buried in aquatic sediments, at least 0.8 (possibly much more) is returned to the atmosphere as gas exchange while the remaining 0.9 Pg y−1 is delivered to the oceans, roughly equally as inorganic and organic carbon. Thus, roughly twice as much C enters inland aquatic systems from land as is exported from land to the sea. Over prolonged time net carbon fluxes in aquatic systems tend to be greater per unit area than in much of the surrounding land. Although their area is small, these freshwater aquatic systems can affect regional C balances. Further, the inclusion of inland, freshwater ecosystems provides useful insight about the storage, oxidation and transport of terrestrial C, and may warrant a revision of how the modern net C sink on land is described.
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| 4. |
- Downing, J. A., et al.
(författare)
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The global abundance and size distribution of lakes, ponds, and impoundments
- 2006
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Ingår i: Limnology and Oceanography. - 0024-3590 .- 1939-5590. ; 51:5, s. 2388-2397
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Tidskriftsartikel (refereegranskat)abstract
- One of the major impediments to the integration of lentic ecosystems into global environmental analyses has been fragmentary data on the extent and size distribution of lakes, ponds, and impoundments. We use new data sources, enhanced spatial resolution, and new analytical approaches to provide new estimates of the global abundance of surface-water bodies. A global model based on the Pareto distribution shows that the global extent of natural lakes is twice as large as previously known (304 million lakes; 4.2 million km(2) in area) and is dominated in area by millions of water bodies smaller than 1 km(2). Similar analyses of impoundments based on inventories of large, engineered dams show that impounded waters cover approximately 0.26 million km(2). However, construction of low-tech farm impoundments is estimated to be between 0.1% and 6% of farm area worldwide, dependent upon precipitation, and represents > 77,000 km(2) globally, at present. Overall, about 4.6 million km(2) of the earth's continental "land" surface (> 3%) is covered by water. These analyses underscore the importance of explicitly considering lakes, ponds, and impoundments, especially small ones, in global analyses of rates and processes.
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| 5. |
- Stirling, R., et al.
(författare)
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Global survey on durability variation – on the effect of the reference species
- 2016
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Ingår i: Proceedings of the International Research Group Annual Meeting 2016.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Climate change due to anthropogenic emissions is the largest environmental challenge of ourtime. Forest-based value chains play an important role in reducing the accumulation of CO2 in the atmosphere. Maximizing the use of wood to tackle climate change requires improved understanding of the service life of timber products. This information can best be obtained from field testing and while there is an abundance of field performance data from sites all over the world, most of the data are not available in a form that can be utilised for service life models.The IRG Durability Database aims to improve the usability of existing performance data and create added value for durability research and service life prediction. The present paper takes the first steps in comparing global field test performance data from the IRG Durability Database for non-durable reference species. Data were obtained from six species above ground and ground contact field tests from 36 sites around the world. For each dataset, decay rates and service life (where applicable) were calculated. Datasets were then grouped together based on test method and species. Decay rate was faster and more uniform in ground contact than above ground. Inground contact, beech decayed most rapidly, followed by Norway spruce and Scots pines apwood. All appeared to be suitable for use as reference species, however slow-grown spruce should be avoided. There were no statistically significant correlations between ground contact decay rate and the Scheffer Climate Index (SCI). In above ground tests, differences in decay ratewere largely related to differences in moisture dynamics. Species with the greatest absorption and retention of water decayed most rapidly. Test methods that absorbed and retained the most moisture (e.g. painted L-joints) resulted in more rapid decay. Above ground decay rate and SCI were significantly correlated in two data sets that had a wide range of SCI values. Correlations were not significant when only European test sites were included. Estimating decay rate from field testing results in highly variable data. Comparing data from global test sites is made more difficult by the absence of common field testing standards.
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| 6. |
- Björnerås, C., et al.
(författare)
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Widespread Increases in Iron Concentration in European and North American Freshwaters
- 2017
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Ingår i: Global Biogeochemical Cycles. - 0886-6236 .- 1944-9224. ; 31:10, s. 1488-1500
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Tidskriftsartikel (refereegranskat)abstract
- Recent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North America in order to gain a clearer understanding of where, to what extent, and why Fe concentrations are on the rise. We found that Fe concentrations have significantly increased in 28% of sites, and decreased in 4%, with most positive trends located in northern Europe. Regions with rising Fe concentrations tend to coincide with those with organic carbon (OC) increases. Fe and OC increases may not be directly mechanistically linked, but may nevertheless be responding to common regional-scale drivers such as declining sulfur deposition or hydrological changes. A role of hydrological factors was supported by covarying trends in Fe and dissolved silica, as these elements tend to stem from similar soil depths. A positive relationship between Fe increases and conifer cover suggests that changing land use and expanded forestry could have contributed to enhanced Fe export, although increases were also observed in nonforested areas. We conclude that the phenomenon of increasing Fe concentrations is widespread, especially in northern Europe, with potentially significant implications for wider ecosystem biogeochemistry, and for the current browning of freshwaters.
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| 7. |
- Crippa, M., et al.
(författare)
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Organic aerosol components derived from 25 AMS data sets across Europe using a consistent ME-2 based source apportionment approach
- 2014
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7324. ; 14:12, s. 6159-6176
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Tidskriftsartikel (refereegranskat)abstract
- Organic aerosols (OA) represent one of the major constituents of submicron particulate matter (PM1) and comprise a huge variety of compounds emitted by different sources. Three intensive measurement field campaigns to investigate the aerosol chemical composition all over Europe were carried out within the framework of the European Integrated Project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) and the intensive campaigns of European Monitoring and Evaluation Programme (EMEP) during 2008 (May-June and September-October) and 2009 (February-March). In this paper we focus on the identification of the main organic aerosol sources and we define a standardized methodology to perform source apportionment using positive matrix factorization (PMF) with the multilinear engine (ME-2) on Aerodyne aerosol mass spectrometer (AMS) data. Our source apportionment procedure is tested and applied on 25 data sets accounting for two urban, several rural and remote and two high altitude sites; therefore it is likely suitable for the treatment of AMS-related ambient data sets. For most of the sites, four organic components are retrieved, improving significantly previous source apportionment results where only a separation in primary and secondary OA sources was possible. Generally, our solutions include two primary OA sources, i.e. hydrocarbon-like OA (HOA) and biomass burning OA (BBOA) and two secondary OA components, i.e. semi-volatile oxygenated OA (SV-OOA) and low-volatility oxygenated OA (LV-OOA). For specific sites cooking-related (COA) and marine-related sources (MSA) are also separated. Finally, our work provides a large overview of organic aerosol sources in Europe and an interesting set of highly time resolved data for modeling purposes.
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| 8. |
- Tranvik, Lars J., et al.
(författare)
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Lakes and reservoirs as regulators of carbon cycling and climate
- 2009
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Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590 .- 1939-5590. ; 54:6:2, s. 2298-2314
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Forskningsöversikt (refereegranskat)abstract
- We explore the role of lakes in carbon cycling and global climate, examine the mechanisms influencing carbon pools and transformations in lakes, and discuss how the metabolism of carbon in the inland waters is likely to change in response to climate. Furthermore, we project changes as global climate change in the abundance and spatial distribution of lakes in the biosphere, and we revise the estimate for the global extent of carbon transformation in inland waters. This synthesis demonstrates that the global annual emissions of carbon dioxide from inland waters to the atmosphere are similar in magnitude to the carbon dioxide uptake by the oceans and that the global burial of organic carbon in inland water sediments exceeds organic carbon sequestration on the ocean floor. The role of inland waters in global carbon cycling and climate forcing may be changed by human activities, including construction of impoundments, which accumulate large amounts of carbon in sediments and emit large amounts of methane to the atmosphere. Methane emissions are also expected from lakes on melting permafrost. The synthesis presented here indicates that (1) inland waters constitute a significant component of the global carbon cycle, (2) their contribution to this cycle has significantly changed as a result of human activities, and (3) they will continue to change in response to future climate change causing decreased as well as increased abundance of lakes as well as increases in the number of aquatic impoundments.
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| 9. |
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| 10. |
- Dobaczewski, J., et al.
(författare)
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Solution of universal nonrelativistic nuclear DFT equations in the Cartesian deformed harmonic-oscillator basis. (IX) HFODD (v3.06h) : A new version of the program
- 2021
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 48:10
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Tidskriftsartikel (refereegranskat)abstract
- We describe the new version (v3.06h) of the code HFODD that solves the universal nonrelativistic nuclear DFT Hartree-Fock or Hartree-Fock-Bogolyubov problem by using the Cartesian deformed harmonic-oscillator basis. In the new version, we implemented the following new features: (i) zero-range three- and four-body central terms, (ii) zero-range three-body gradient terms, (iii) zero-range tensor terms, (iv) zero-range isospin-breaking terms, (v) finite-range higher-order regularized terms, (vi) finite-range separable terms, (vii) zero-range two-body pairing terms, (viii) multi-quasiparticle blocking, (ix) Pfaffian overlaps, (x) particle-number and parity symmetry restoration, (xi) axialization, (xii) Wigner functions, (xiii) choice of the harmonic-oscillator basis, (xiv) fixed omega partitions, (xv) consistency formula between energy and fields, and we corrected several errors in the previous versions.
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