The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite ...evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30 ± 30 petagrams of carbon to 203 ± 161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55 ± 50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12-17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon-climate feedback that could accelerate climate change.
To study disability-management self-efficacy (DMSE) and its correlates in a large sample of Dutch people with long-standing spinal cord injury (SCI). DMSE is the confidence that people with SCI may ...have in their ability to manage the consequences of their condition with respect to the various domains in their life. Research questions were: (1) What is the level of DMSE in Dutch people with long-standing SCI?; (2) Is DMSE associated with demographic and lesion characteristics?; and (3) Is DMSE associated with participation and life satisfaction if these associations are adjusted for demographic and lesion characteristics and mood?
Eligible people were identified from all eight rehabilitation centers with a specialty in SCI rehabilitation in the Netherlands (N=261). Data were collected using a self-report questionnaire. DMSE was measured using the University of Washington Self-Efficacy Scale-Short Form (UW-SES-6). Correlation and linear regression analyses were used.
Levels of UW-SES-6 scores were largely independent of demographic and lesion characteristics. UW-SES-6 scores were bivariately moderately to strongly associated with mood (0.47), participation (0.39-0.51) and life satisfaction (0.46). In the regression analyses, UW-SES-6 scores still explained a significant amount of variance of participation (standardized β 0.31-0.33) and life satisfaction (standardized β 0.21) when controlling for demographic and lesion characteristics and mood, and explained an additional 3.2-8.1% of the variance of participation and life satisfaction.
DMSE is a psychological resource associated with higher levels of participation and life satisfaction after SCI. The UW-SES-6 is a brief and easy to use measure of this psychological resource.
Seed performance after dispersal is highly dependent on parental environmental cues, especially during seed formation and maturation. Here we examine which environmental factors are the most dominant ...in this respect and whether their effects are dependent on the genotypes under investigation. We studied the influence of light intensity, photoperiod, temperature, nitrate, and phosphate during seed development on five plant attributes and thirteen seed attributes, using 12 Arabidopsis genotypes that have been reported to be affected in seed traits. As expected, the various environments during seed development resulted in changed plant and/or seed performances. Comparative analysis clearly indicated that, overall, temperature plays the most dominant role in both plant and seed performance, whereas light has a prominent impact on plant traits. In comparison to temperature and light, nitrate mildly affected some of the plant and seed traits while phosphate had even less influence on those traits. Moreover, clear genotype-by-environment interactions were identified. This was shown by the fact that individual genotypes responded differentially to the environmental conditions. Low temperature significantly increased seed dormancy and decreased seed longevity of NILDOG1 and cyp707a1-1, whereas low light intensity increased seed dormancy and decreased seed longevity of NILDOG3 and NILDOG6. This also indicates that different genetic and molecular pathways are involved in the plant and seed responses. By identifying environmental conditions that affect the dormancy vs longevity correlation in the same way as previously identified naturally occurring loci, we have identified selective forces that probably shaped evolution for these important seed traits.
Highlight textThe genotype-by-environment interactions of five parental environments with seed and plant performance are mediated by distinct genetic and molecular pathways, and the selective pressures that have shaped their natural variation.
Current climate change has led to latitudinal and altitudinal range expansions of numerous species. During such range expansions, plant species are expected to experience changes in interactions with ...other organisms, especially with belowground biota that have a limited dispersal capacity. Nematodes form a key component of the belowground food web as they include bacterivores, fungivores, omnivores and root herbivores. However, their community composition under climate change‐driven intracontinental range‐expanding plants has been studied almost exclusively under controlled conditions, whereas little is known about actual patterns in the field. Here, we use novel molecular sequencing techniques combined with morphological quantification in order to examine nematode communities in the rhizospheres of four range‐expanding and four congeneric native species along a 2,000 km latitudinal transect from South‐Eastern to North‐Western Europe. We tested the hypotheses that latitudinal shifts in nematode community composition are stronger in range‐expanding plant species than in congeneric natives and that in their new range, range‐expanding plant species accumulate fewest root‐feeding nematodes. Our results show latitudinal variation in nematode community composition of both range expanders and native plant species, while operational taxonomic unit richness remained the same across ranges. Therefore, range‐expanding plant species face different nematode communities at higher latitudes, but this is also the case for widespread native plant species. Only one of the four range‐expanding plant species showed a stronger shift in nematode community composition than its congeneric native and accumulated fewer root‐feeding nematodes in its new range. We conclude that variation in nematode community composition with increasing latitude occurs for both range‐expanding and native plant species and that some range‐expanding plant species may become released from root‐feeding nematodes in the new range.
In Europe, we explored latitudinal community shifts for nematodes—abundant soil organisms that include root herbivores—in the rhizospheres of climate change‐driven range‐expanding plant species. We sampled nematode communities of several range‐expanding plant species along their expansion trajectory and compared these nematode communities with those of related plant species that are native along the entire expansion gradient. We show that nematode communities change with latitude, but that the strength of nematode community shifts strongly depends on range‐expanding plant species.
Aims Mild cognitive deficits have been determined in both types of diabetes using neurocognitive tests. Little is known about the degree to which patients complain about their cognitive functioning. ...This study set out to investigate the magnitude and correlates of self‐reported cognitive failure in adult out‐patients with Type 1 and Type 2 diabetes.
Methods Subjective cognitive functioning was measured in 187 diabetic patients using the Cognitive Failures Questionnaire (CFQ). Demographic and clinical characteristics were retrieved from the medical records. The Patient Health Questionnaire 9 items (PHQ‐9) was self‐administered along with the CFQ to correct for the confounding effect of depression.
Results Analyses were based on 55 patients with Type 1 diabetes and 100 patients with Type 2 diabetes. No difference in mean CFQ score was observed between Type 1 and Type 2 diabetic patients or between Type 1 diabetic patients and healthy control subjects. Female patients with Type 2 diabetes reported significantly fewer cognitive complaints compared with female healthy control subjects. None of the demographic variables and diabetes‐related complications was associated with subjective cognitive complaints. A strong positive association was found between depression symptomatology and frequency of self‐reported cognitive failure.
Conclusions Our study could not confirm elevated subjective cognitive complaints in a group of Type 1 and Type 2 diabetes patients, as might be expected given the observed elevated rates of mild cognitive dysfunction in patients with diabetes. Self‐reported cognitive failure appears largely determined by depressive symptomatology. Therefore, affective status should be included in any cognitive assessment procedure.
Major depression and type 2 diabetes often co-occur. Novel treatment strategies for depression in type 2 diabetes patients are warranted, as depression in type 2 diabetes patients is associated with ...poor prognosis and treatment results. Major depression and concurrent sleep disorders have been related to disturbances of the biological clock. The biological clock is also involved in regulation of glucose metabolism by modulating peripheral insulin sensitivity. Light therapy has been shown to be an effective antidepressant that 'resets' the biological clock. We here describe the protocol of a study that evaluates the hypothesis that light therapy improves mood as well as insulin sensitivity in patients with a major depressive episode and type 2 diabetes.
This study is a randomised, double-blind, parallel-arm trial in 98 participants with type 2 diabetes and a major depressive episode, according to DSM-IV criteria. We will assess whether light therapy improves depressive symptoms and insulin sensitivity, our primary outcome measures, and additionally investigate whether these effects are mediated by restoration of the circadian rhythmicity, as measured by sleep and hypothalamic-pituitary-adrenal axis activity. Participants will be randomly allocated to a bright white-yellowish light condition or dim green light condition. Participants will undergo light therapy for half an hour every morning for 4 weeks at home. At several time points, namely before the start of light therapy, during light therapy, after completion of 4 weeks of light therapy and after 4 weeks follow-up, several psychometrical, psychophysiological and glucometabolic measures will be performed.
If light therapy effectively improves mood and insulin sensitivity in type 2 diabetes patients with a major depressive episode, light therapy may be a valuable patient friendly addition to the currently available treatment strategies. Additionally, if our data support the role of restoration of circadian rhythmicity, such an observation may guide further development of chronobiological treatment strategies in this patient population.
The Netherlands Trial Register (NTR) NTR4942 . Registered 13 January 2015.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Almost nothing is known about the potential negative effects of Internet-based psychological treatments for depression. This study aims at investigating deterioration and its moderators within ...randomized trials on Internet-based guided self-help for adult depression, using an individual patient data meta-analyses (IPDMA) approach.
Studies were identified through systematic searches (PubMed, PsycINFO, EMBASE, Cochrane Library). Deterioration in participants was defined as a significant symptom increase according to the reliable change index (i.e. 7.68 points in the CES-D; 7.63 points in the BDI). Two-step IPDMA procedures, with a random-effects model were used to pool data.
A total of 18 studies (21 comparisons, 2079 participants) contributed data to the analysis. The risk for a reliable deterioration from baseline to post-treatment was significantly lower in the intervention v. control conditions (3.36 v. 7.60; relative risk 0.47, 95% confidence interval 0.29-0.75). Education moderated effects on deterioration, with patients with low education displaying a higher risk for deterioration than patients with higher education. Deterioration rates for patients with low education did not differ statistically significantly between intervention and control groups. The benefit-risk ratio for patients with low education indicated that 9.38 patients achieve a treatment response for each patient experiencing a symptom deterioration.
Internet-based guided self-help is associated with a mean reduced risk for a symptom deterioration compared to controls. Treatment and symptom progress of patients with low education should be closely monitored, as some patients might face an increased risk for symptom deterioration. Future studies should examine predictors of deterioration in patients with low education.
Soil organisms have an important role in aboveground community dynamics and ecosystem functioning in terrestrial ecosystems. However, most studies have considered soil biota as a black box or ...focussed on specific groups, whereas little is known about entire soil networks. Here we show that during the course of nature restoration on abandoned arable land a compositional shift in soil biota, preceded by tightening of the belowground networks, corresponds with enhanced efficiency of carbon uptake. In mid- and long-term abandoned field soil, carbon uptake by fungi increases without an increase in fungal biomass or shift in bacterial-to-fungal ratio. The implication of our findings is that during nature restoration the efficiency of nutrient cycling and carbon uptake can increase by a shift in fungal composition and/or fungal activity. Therefore, we propose that relationships between soil food web structure and carbon cycling in soils need to be reconsidered.
It is increasingly acknowledged that climate change is influencing terrestrial ecosystems by increased drought and rainfall intensities. Soil microbes are key drivers of many processes in terrestrial ...systems and rely on water in soil pores to fulfill their life cycles and functions. However, little is known on how drought and rainfall fluctuations, which affect the composition and structure of microbial communities, persist once original moisture conditions have been restored. Here, we study how simulated short-term drying and re-wetting events shape the community composition of soil fungi and prokaryotes. In a mesocosm experiment, soil was exposed to an extreme drought, then re-wetted to optimal moisture (50% WHC, water holding capacity) or to saturation level (100% WHC). Composition, community structure and diversity of microbes were measured by sequencing ITS and 16S rRNA gene amplicons 3 weeks after original moisture content had been restored. Drying and extreme re-wetting decreased richness of microbial communities, but not evenness. Abundance changes were observed in only 8% of prokaryote OTUs, and 25% of fungal OTUs, whereas all other OTUs did not differ between drying and re-wetting treatments. Two specific legacy response groups (LRGs) were observed for both prokaryotes and fungi. OTUs belonging to the first LRG decreased in relative abundance in soil with a history of drought, whereas OTUs that increased in soil with a history of drought formed a second LRG. These microbial responses were spread among different phyla. Drought appeared to be more important for the microbial community composition than the following extreme re-wetting. 16S profiles were correlated with both inorganic N concentration and basal respiration and ITS profiles correlated with fungal biomass. We conclude that a drying and/or an extreme re-wetting history can persist in soil microbial communities via specific response groups composed of members with broad phylogenetic origins, with possible functional consequences on soil processes and plant species. As a large fraction of OTUs responding to drying and re-wetting belonged to the rare biosphere, our results suggest that low abundant microbial species are potentially important for ecosystem responses to extreme weather events.
Microbiomes play a pivotal role in plant growth and health, but the genetic factors involved in microbiome assembly remain largely elusive. Here, we map the molecular features of the rhizosphere ...microbiome as quantitative traits of a diverse hybrid population of wild and domesticated tomato. Gene content analysis of prioritized tomato quantitative trait loci suggests a genetic basis for differential recruitment of various rhizobacterial lineages, including a Streptomyces-associated 6.31 Mbp region harboring tomato domestication sweeps and encoding, among others, the iron regulator FIT and the water channel aquaporin SlTIP2.3. Within metagenome-assembled genomes of root-associated Streptomyces and Cellvibrio, we identify bacterial genes involved in metabolism of plant polysaccharides, iron, sulfur, trehalose, and vitamins, whose genetic variation associates with specific tomato QTLs. By integrating 'microbiomics' and quantitative plant genetics, we pinpoint putative plant and reciprocal rhizobacterial traits underlying microbiome assembly, thereby providing a first step towards plant-microbiome breeding programs.
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