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- Callaghan, Terry, et al.
(författare)
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Multi-Decadal Changes in Tundra Environments and Ecosystems : Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)
- 2011
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40:6, s. 705-716
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the responses of tundra systemsto global change has global implications. Most tundraregions lack sustained environmental monitoring and oneof the only ways to document multi-decadal change is toresample historic research sites. The International PolarYear (IPY) provided a unique opportunity for such researchthrough the Back to the Future (BTF) project (IPY project#512). This article synthesizes the results from 13 paperswithin this Ambio Special Issue. Abiotic changes includeglacial recession in the Altai Mountains, Russia; increasedsnow depth and hardness, permafrost warming, andincreased growing season length in sub-arctic Sweden;drying of ponds in Greenland; increased nutrient availabilityin Alaskan tundra ponds, and warming at mostlocations studied. Biotic changes ranged from relativelyminor plant community change at two sites in Greenland tomoderate change in the Yukon, and to dramatic increasesin shrub and tree density on Herschel Island, and in subarcticSweden. The population of geese tripled at one sitein northeast Greenland where biomass in non-grazed plotsdoubled. A model parameterized using results from a BTFstudy forecasts substantial declines in all snowbeds andincreases in shrub tundra on Niwot Ridge, Colorado overthe next century. In general, results support and provideimproved capacities for validating experimental manipulation,remote sensing, and modeling studies.
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| 2. |
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| 3. |
- Löfgren, Stefan, et al.
(författare)
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Impact of whole-tree harvest on soil and stream water acidity in southern Sweden based on HD-MINTEQ simulations and pH-sensitivity
- 2017
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383, s. 49-60
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Tidskriftsartikel (refereegranskat)abstract
- The shift in major drivers of acidification from sulfur deposition to biological acidification has put the focus on the impact of biomass harvest for bioenergy on the acid base status of forests soils and surface waters. This paper presents a model-based assessment in which the impact of whole-tree harvest (WTH) is compared with that of no harvest at two different sulfur deposition levels by use of the HD-MINTEQ model. Additionally, the pH-sensitivity of 179 randomly selected boreal headwater streams was assessed. The results indicate that the exchangeable Ca2+ pool in humus and mineral soils (<= B-horizon) is most affected by harvest. Concerning the pH, the WTH impact is restricted to shallow soils and for a much shorter period of time. The impact of WTH on the soil solution was primarily restricted to the recharge area and much less pronounced in the discharge area. Due to high buffering capacity of riparian soils and low pH-sensitivity of many headwater streams, the pH effects of WTH on surface waters will most probably be small, at least over a rotation period of several decades. Over time perspectives of multiple rotations, the pH effects are more uncertain due to a possible slow successive protonation of organic matter in the riparian zone. Another important aspect is the currently restricted availability of mobile anion charge balancing the acidity produced by tree growth. Therefore, the acidity is to a large extent arrested in the soil. At the current low S deposition levels, southwestern Sweden seems to be the least vulnerable region to further acid input due to high buffer capacity at low pH. The streams in central and northern Sweden are much more pH-sensitive, but restricted availability of mobile strong acid anions and large buffer capacity in the soils make them less vulnerable to WTH. The partly diverging results between experimental and model studies indicate that one or more processes (hydrological, chemical or biological) are not fully understood or that available data are lacking for a proper parameterization. Thus, the results from long-term WTH experiments are very important for understanding the processes involved as well as for improving and validating model predictions. We therefore encourage societal support of maintaining monitoring and research coupled to such experiments. For the future and for improving our current understanding of biogeochemical dynamics in forest ecosystems subjected to active forestry as well as for policy and management purposes, a mixture of experiments and models ought to be used. (C) 2016 Elsevier B.V. All rights reserved.
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| 4. |
- Olsson, Mikael E., et al.
(författare)
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Localization of enzymes of artemisinin biosynthesis to the apical cells of glandular secretory trichomes of Artemisia annua L
- 2009
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Ingår i: Phytochemistry. - : Elsevier BV. - 0031-9422 .- 1873-3700. ; 70:9, s. 1123-1128
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Tidskriftsartikel (refereegranskat)abstract
- A method based on the laser microdissection pressure catapulting technique has been developed for isolation of whole intact cells. Using a modified tissue preparation method, one outer pair of apical cells and two pairs of sub-apical, chloroplast-containing cells, were isolated from glandular secretory trichomes of Artemisia annua. A. annua is the source of the widely used antimalarial drug artemisinin. The biosynthesis of artemisinin has been proposed to be located to the glandular trichomes. The first committed steps in the conversion of FPP to artemisinin are conducted by amorpha-4,11-diene synthase, amorpha-4,11-diene hydroxylase, a cytochrome P450 monooxygenase (CYP71AV1) and artemisinic aldehyde Delta 11(13) reductase. The expression of the three biosynthetic enzymes in the different cell types has been studied. In addition, the expression of farnesyldiphosphate synthase producing the precursor of artemisinin has been investigated. Our experiments showed expression of farnesyldiphosphate synthase in apical and sub-apical cells as well as in mesophyl cells while the three enzymes involved in artemisinin biosynthesis were expressed only in the apical cells. Elongation factor 1 alpha was used as control and it was expressed in all cell types. We conclude that artemisinin biosynthesis is taking place in the two outer apical cells while the two pairs of chloroplast-containing cells have other functions in the overall metabolism of glandular trichomes.
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| 5. |
- Scaini, Anna, et al.
(författare)
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Pathways from research to sustainable development: Insights from ten research projects in sustainability and resilience
- 2024
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Ingår i: AMBIO. - : SPRINGER. - 0044-7447 .- 1654-7209.
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Tidskriftsartikel (refereegranskat)abstract
- Drawing on collective experience from ten collaborative research projects focused on the Global South, we identify three major challenges that impede the translation of research on sustainability and resilience into better-informed choices by individuals and policy-makers that in turn can support transformation to a sustainable future. The three challenges comprise: (i) converting knowledge produced during research projects into successful knowledge application; (ii) scaling up knowledge in time when research projects are short-term and potential impacts are long-term; and (iii) scaling up knowledge across space, from local research sites to larger-scale or even global impact. Some potential pathways for funding agencies to overcome these challenges include providing targeted prolonged funding for dissemination and outreach, and facilitating collaboration and coordination across different sites, research teams, and partner organizations. By systematically documenting these challenges, we hope to pave the way for further innovations in the research cycle.
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