| 1. |
- Ainsworth, Elizabeth A., et al.
(författare)
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Next generation of elevated [CO2] experiments with crops: a critical investment for feeding the future world
- 2008
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Ingår i: Plant, Cell and Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 31:9, s. 1317-1324
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Tidskriftsartikel (refereegranskat)abstract
- A rising global population and demand for protein-rich diets are increasing pressure to maximize agricultural productivity. Rising atmospheric [CO2] is altering global temperature and precipitation patterns, which challenges agricultural productivity. While rising [CO2] provides a unique opportunity to increase the productivity of C-3 crops, average yield stimulation observed to date is well below potential gains. Thus, there is room for improving productivity. However, only a fraction of available germplasm of crops has been tested for CO2 responsiveness. Yield is a complex phenotypic trait determined by the interactions of a genotype with the environment. Selection of promising genotypes and characterization of response mechanisms will only be effective if crop improvement and systems biology approaches are closely linked to production environments, that is, on the farm within major growing regions. Free air CO2 enrichment (FACE) experiments can provide the platform upon which to conduct genetic screening and elucidate the inheritance and mechanisms that underlie genotypic differences in productivity under elevated [CO2]. We propose a new generation of large-scale, low-cost per unit area FACE experiments to identify the most CO2-responsive genotypes and provide starting lines for future breeding programmes. This is necessary if we are to realize the potential for yield gains in the future.
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| 2. |
- Calfapietra, Carlo, et al.
(författare)
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Challenges in elevated CO2 experiments on forests
- 2010
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Ingår i: Trends in Plant Science. - : Elsevier BV. - 1360-1385. ; 15:1, s. 5-10
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Forskningsöversikt (refereegranskat)abstract
- Current forest Free Air CO2 Enrichment (FACE) experiments are reaching completion. Therefore, it is time to define the scientific goals and priorities of future experimental facilities. In this opinion article, we discuss the following three overarching issues (i) What are the most urgent scientific questions and how can they be addressed? (ii) What forest ecosystems should be investigated? (iii) Which other climate change factors should be coupled with elevated CO2 concentrations in future experiments to better predict the effects of climate change? Plantations and natural forests can have conflicting purposes for high productivity and environmental protection. However, in both cases the assessment of carbon balance and how this will be affected by elevated CO2 concentrations and the interacting climate change factors is the most pressing priority for future experiments.
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| 3. |
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| 4. |
- Miglietta, F, et al.
(författare)
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Spatial and Temporal Performance of the MiniFACE (Free Air CO2 Enrichment) System on Bog Ecosystems in Northern and Central Europe
- 2001
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Ingår i: Environmental Monitoring & Assessment. - 1573-2959. ; 66:2, s. 107-127
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Tidskriftsartikel (refereegranskat)abstract
- The Bog Ecosystem Research Initiative (BERI) projectwas initiated to investigate, at five climaticallydifferent sites across Europe, the effects of elevatedCO2 and N deposition on the net exchange ofCO2 and CH4 between bogs and the atmosphere,and to study the effects of elevated CO2 and Ndeposition on the plant biodiversity of bogcommunities. A major challenge to investigate theeffects of elevated CO2 on vegetation andecosystems is to apply elevated CO2concentrations to growing vegetation without changingthe physical conditions like climate and radiation.Most available CO2 enrichment methods disturb thenatural conditions to some degree, for instance closedchambers or open top chambers. Free Air CO2Enrichment (FACE) systems have proven to be suitableto expose plants to elevated CO2 concentrationswith minimal disturbance of their natural environment.The size and spatial scale of the vegetation studiedwithin the BERI project allowed the use of a modifiedversion of a small FACE system called MiniFACE. Thispaper describes the BERI MiniFACE design as well asits temporal and spatial performance at the five BERIfield locations. The temporal performance of theMiniFACE system largely met the quality criteriadefined by the FACE Protocol. One minute averageCO2 concentrations measured at the centre of thering stayed within 20% of the pre-set target for morethan 95% of the time. Increased wind speeds werefound to improve the MiniFACE system's temporalperformance. Spatial analyses showed no apparentCO2 gradients across a ring during a 4 day periodand the mean differences between each sampling pointand the centre of the ring did not exceed 10%.Observations made during a windy day, causing aCO2 concentration gradient, and observations madeduring a calm day indicated that short term gradientstend to average out over longer periods of time. On aday with unidirectional strong winds, CO2concentrations at the upwind side of the ring centrewere higher than those made at the centre and at thedownwind side of the ring centre, but the bell-shapeddistribution was found basically the same for thecentre and the four surrounding measurement points,implying that the short term (1 sec) variability ofCO2 concentrations across the MiniFACE ring isalmost the same at any point in the ring. Based on gasdispersion simulations and measured CO2concentration profiles, the possible interferencebetween CO2-enriched and control rings was foundto be negligible beyond a centre-to-centre ringdistance of 6 m.
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| 5. |
- Mikkelsen, T N, et al.
(författare)
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Experimental design of multifactor climate change experiments with elevated CO2, warming and drought: the CLIMAITE project
- 2008
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Ingår i: Functional Ecology. - : Wiley. - 1365-2435 .- 0269-8463. ; 22:1, s. 185-195
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Tidskriftsartikel (refereegranskat)abstract
- Recent findings indicate that the interactions among CO2, temperature and water can be substantial, and that the combined effects on the biological systems of several factors may not be predicted from experiments with one or a few factors. Therefore realistic multifactorial experiments involving a larger set of main factors are needed. We describe a new Danish climate change-related field scale experiment, CLIMAITE, in a heath/grassland ecosystem. CLIMAITE is a full factorial combination of elevated CO2, elevated temperature and prolonged summer drought. The manipulations are intended to mimic anticipated major environmental changes at the site by year 2075 as closely as possible. The impacts on ecosystem processes and functioning (at ecophysiological levels, through responses by individuals and communities to ecosystem-level responses) are investigated simultaneously. The increase of [CO2] closely corresponds with the scenarios for year 2075, while the warming treatment is at the lower end of the predictions and seems to be the most difficult treatment to increase without unwanted side effects on the other variables. The drought treatment follows predictions of increased frequency of drought periods in summer. The combination of the treatments does not create new unwanted side effects on the treatments relative to the treatments alone.
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| 6. |
- Gioli, B, et al.
(författare)
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Comparison between tower and aircraft-based eddy covariance fluxes in five European regions
- 2004
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Ingår i: Agricultural and Forest Meteorology. - : Elsevier BV. - 1873-2240 .- 0168-1923. ; 127:1-2, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- Airborne eddy covariance measurements provide a unique opportunity to directly measure surface energy, mass and momentum fluxes at the regional scale. This offers the possibility to complement the data that are obtained by the ground-based eddy covariance networks and to validate estimates of the surface fluxes that can be obtained by means of satellite products and models. The overall accuracy and the reliability of airborne eddy covariance measurements have already been assessed in the past for different platforms. More recently an international collaboration between several research laboratories and a European aeronautical manufacturer led to the development of a new small environmental research aircraft, called the Sky Arrow ERA (Environmental Research Aircraft). This aircraft has been used in the framework of the European Research Project RECAB (Regional Assessment and Modelling of the Carbon Balance in Europe), that is part of the CarboEurope projects cluster, to measure surface mass and energy exchange at five different European locations. An extensive comparison between airborne and ground-based flux data at seven flux measurement sites, showed the overall matching between airborne and tower data. While friction velocity and latent heat flux estimates made by airborne and tower data were comparable at all sites and under whatever conditions, substantial and consistent underestimation of CO2 (28% on average) and sensible heat fluxes (35% on average) was observed. Differences in the aircraft and tower footprint and flux divergence with height explained most of the discrepancies. (C) 2004 Elsevier B.V. All rights reserved.
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