| 1. |
- Costello, David M., et al.
(författare)
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Global patterns and controls of nutrient immobilization on decomposing cellulose in riverine ecosystems
- 2022
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Ingår i: Global Biogeochemical Cycles. - : John Wiley & Sons. - 0886-6236 .- 1944-9224. ; 36:3
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Tidskriftsartikel (refereegranskat)abstract
- Microbes play a critical role in plant litter decomposition and influence the fate of carbon in rivers and riparian zones. When decomposing low-nutrient plant litter, microbes acquire nitrogen (N) and phosphorus (P) from the environment (i.e., nutrient immobilization), and this process is potentially sensitive to nutrient loading and changing climate. Nonetheless, environmental controls on immobilization are poorly understood because rates are also influenced by plant litter chemistry, which is coupled to the same environmental factors. Here we used a standardized, low-nutrient organic matter substrate (cotton strips) to quantify nutrient immobilization at 100 paired stream and riparian sites representing 11 biomes worldwide. Immobilization rates varied by three orders of magnitude, were greater in rivers than riparian zones, and were strongly correlated to decomposition rates. In rivers, P immobilization rates were controlled by surface water phosphate concentrations, but N immobilization rates were not related to inorganic N. The N:P of immobilized nutrients was tightly constrained to a molar ratio of 10:1 despite wide variation in surface water N:P. Immobilization rates were temperature-dependent in riparian zones but not related to temperature in rivers. However, in rivers nutrient supply ultimately controlled whether microbes could achieve the maximum expected decomposition rate at a given temperature. Collectively, we demonstrated that exogenous nutrient supply and immobilization are critical control points for decomposition of organic matter.
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| 2. |
- Santangelo, James S., et al.
(författare)
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Global urban environmental change drives adaptation in white clover
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 375
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Tidskriftsartikel (refereegranskat)abstract
- Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural dines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.
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| 3. |
- Stickley, Andrew, et al.
(författare)
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Disability and loneliness in nine countries of the former Soviet Union
- 2021
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Ingår i: Disability and Health Journal. - : Elsevier. - 1936-6574 .- 1876-7583. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: People with disabilities (PWD) often face structural and other barriers to community involvement and may therefore be at risk of loneliness. Yet, so far, this issue has received little attention.OBJECTIVE: This cross-sectional study aimed to examine the association between disability and loneliness in nine countries of the former Soviet Union (FSU).METHODS: Data were analyzed from 18000 respondents aged ≥18 that came from the Health in Times of Transition (HITT) survey that was undertaken in Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Russia and Ukraine in 2010/11. Respondents reported on whether they had a disability (no/yes) and its severity. A single-item question was used to assess loneliness. Logistic regression analysis was used to examine the associations.RESULTS: Across the countries, 6.8% of respondents reported being disabled. In a fully adjusted combined country analysis, disability was associated with higher odds for loneliness (odds ratio: 1.30, 95% confidence interval: 1.06-1.60). In an analysis restricted to PWD, individuals in the most severe disability category (Group 1) had over two times higher odds for loneliness when compared to those in the least severe disability category (Group 3).CONCLUSIONS: Disability is associated with higher odds for reporting loneliness in the FSU countries and this association is especially strong among those who are more severely disabled. An increased focus on the relationship between disability and loneliness is now warranted given the increasing recognition of loneliness as a serious public health problem that is associated with a number of detrimental outcomes.
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