| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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| 3. |
- Andresen, Louise C., et al.
(författare)
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Seasonal changes in nitrogen availability, and root and microbial uptake of (15)N(13)C(9)-phenylalanine and (15)N-ammonium in situ at a temperate heath
- 2011
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 51, s. 94-101
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Tidskriftsartikel (refereegranskat)abstract
- In the plant biosynthesis of secondary compounds, phenylalanine is a precursor of condensed tannins. Tannins are deposited into the soil in plant root exudates and dead plant material and have been suggested to precipitate some soil nutrients and hence reduce nutrient availability for plants. Free amino acid, inorganic and microbial N concentration during the growing season was investigated in an ecosystem with a natural tannin chemosphere. The influence of tannins on the uptake of nitrogen in plants and microbes was followed by injecting tannic acid (TA), ammonium-(15)N and phenylalanine-(15)N/(13)C(9). Plants preferred ammonium over phenylalanine, while microbes had no preference. Soil microbes had a 77% uptake of intact phenylalanine. Phenylalanine was acquired intact by both grasses and Calluna, with 63% and 38% uptake of intact phenylalanine in grass fine roots and Calluna roots, respectively. Inorganic N and amino acid concentrations were lowest in the period with highest plant activity and grass root biomass but were unaffected by TA addition. (C) 2011 Elsevier B.V. All rights reserved.
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| 4. |
- Andresen, Louise C., et al.
(författare)
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Uptake of pulse injected nitrogen by soil microbes and mycorrhizal and non-mycorrhizal plants in a species-diverse subarctic heath ecosystem
- 2008
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 313:1-2, s. 283-295
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Tidskriftsartikel (refereegranskat)abstract
- N-15 labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of N-15 label in mycorrhizal and non-mycorrhizal plants and in soil microorganisms, in order to reveal probable differences in acquisition patterns between the two functional plant types and between plants and soil microorganisms. Three weeks after the label addition, with the N-15-forms added with same amount of nitrogen per square meter, we analyzed the N-15-enrichment in total soil, in soil K2SO4 (0.5 M) extracts and in the microbial biomass after vacuum-incubation of soil in chloroform and subsequent K2SO4 extraction. Furthermore the N-15-enrichment was analyzed in current years leaves of the dominant plant species sampled three, five and 21 days after label addition. The soil microorganisms had very high N-15 recovery from all the N sources compared to plants. Microorganisms incorporated most N-15 from the glutamic acid source, intermediate amounts of N-15 from the glycine source and least N-15 from the NH4+ source. In contrast to microorganisms, all ten investigated plant species generally acquired more N-15 label from the NH4+ source than from the amino acid sources. Non-mycorrhizal plant species showed higher concentration of N-15 label than mycorrhizal plant species 3 days after labeling, while 21 days after labeling their acquisition of N-15 label from amino acid injection was lower than, and the acquisition of N-15 label from NH4 injection was similar to that of the mycorrhizal species. We conclude that the soil microorganisms were more efficient than plants in acquiring pulses of nutrients which, under natural conditions, occur after e. g. freeze-thaw and dry rewet events, although of smaller size. It also appears that the mycorrhizal plants in the short term may be less efficient than non-mycorrhizal plants in nitrogen acquisition, but in a longer term show larger nitrogen acquisition than non-mycorrhizal plants. However, the differences in N-15 uptake patterns may also be due to differences in leaf longevity and woodiness between plant functional groups.
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