| 1. |
- Abramoff, Rose Z., et al.
(författare)
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How much carbon can be added to soil by sorption?
- 2021
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Ingår i: Biogeochemistry. - : Springer Nature. - 0168-2563 .- 1573-515X. ; 152:2-3, s. 127-142
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Tidskriftsartikel (refereegranskat)abstract
- Quantifying the upper limit of stable soil carbon storage is essential for guiding policies to increase soil carbon storage. One pool of carbon considered particularly stable across climate zones and soil types is formed when dissolved organic carbon sorbs to minerals. We quantified, for the first time, the potential of mineral soils to sorb additional dissolved organic carbon (DOC) for six soil orders. We compiled 402 laboratory sorption experiments to estimate the additional DOC sorption potential, that is the potential of excess DOC sorption in addition to the existing background level already sorbed in each soil sample. We estimated this potential using gridded climate and soil geochemical variables within a machine learning model. We find that mid- and low-latitude soils and subsoils have a greater capacity to store DOC by sorption compared to high-latitude soils and topsoils. The global additional DOC sorption potential for six soil orders is estimated to be 107 ± 13 Pg C to 1 m depth. If this potential was realized, it would represent a 7% increase in the existing total carbon stock.
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| 2. |
- He, Haoran, et al.
(författare)
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Linking soil depth to aridity effects on soil microbial community composition, diversity and resource limitation
- 2023
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Ingår i: Catena. - 0341-8162. ; 232
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Tidskriftsartikel (refereegranskat)abstract
- With ongoing climate change, aridity is increasing worldwide, affecting biodiversity and ecosystem function in drylands. However, how the depth-profile microbial community structure and metabolic limitations change along aridity gradients are still poorly explored. Here, 16S rRNA and ITS amplicon sequencing and ecoenzymatic stoichiometry analysis were used to investigate both bacterial and fungal diversities and resource limitations in 1 m depth profiles across a wide aridity gradient (0.51–0.78) in a semiarid region. Results showed a sharp decrease in microbial diversity with soil depth, accompanied by an increase in microbial phosphorus (P) vs. N (nitrogen) limitation and a decrease in microbial carbon (C) vs. nutrient limitation. Aridity led to a strong shift in microbial community composition, but aridity has a threshold effect on microbial resource limitation through impacts on soil pH and C/P or N/P. When the aridity threshold (1-precipitation/evapotranspiration) exceeds 0.65, relationship between aridity and microbial resource demand was decoupled; but at aridity threshold = 0.65, microbial relative C limitation and C-acquiring enzyme activity dropped. These results suggest that aridity might have a stronger influence on microbial community composition, than on diversity, shaped by inherent soil biotic factors (i.e., MBC:MBP or MBN:MBP). These findings suggest that soil microbial diversity or enzymatic stoichiometry may be not necessary to mirror changes in water availability in the drylands, while aridity would be well explained by microbial community composition.
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| 3. |
- Richards, Stephen, et al.
(författare)
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Genome Sequence of the Pea Aphid Acyrthosiphon pisum
- 2010
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:2, s. e1000313-
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Tidskriftsartikel (refereegranskat)abstract
- Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.
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| 4. |
- Song, Dongsheng, et al.
(författare)
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An in-plane magnetic chiral dichroism approach for measurement of intrinsic magnetic signals using transmitted electrons
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Electron energy-loss magnetic chiral dichroism is a powerful technique that allows the local magnetic properties of materials to be measured quantitatively with close-to-atomic spatial resolution and element specificity in the transmission electron microscope. Until now, the technique has been restricted to measurements of the magnetic circular dichroism signal in the electron beam direction. However, the intrinsic magnetization directions of thin samples are often oriented in the specimen plane, especially when they are examined in magnetic-field-free conditions in the transmission electron microscope. Here, we introduce an approach that allows in-plane magnetic signals to be measured using electron magnetic chiral dichroism by selecting a specific diffraction geometry. We compare experimental results recorded from a cobalt nanoplate with simulations to demonstrate that an electron magnetic chiral dichroism signal originating from in-plane magnetization can be detected successfully.
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