Search results for "Global Change"
showing 10 items of 639 documents
Human norovirus hyper-mutation revealed by ultra-deep sequencing
2016
Human noroviruses (NoVs) are a major cause of gastroenteritis worldwide. It is thought that, similar to other RNA viruses, high mutation rates allow NoVs to evolve fast and to undergo rapid immune escape at the population level. However, the rate and spectrum of spontaneous mutations of human NoVs have not been quantified previously. Here, we analyzed the intra-patient diversity of the NoV capsid by carrying out RT-PCR and ultra-deep sequencing with 100,000-fold coverage of 16 stool samples from symptomatic patients. This revealed the presence of low-frequency sequences carrying large numbers of U-to-C or A-to-G base transitions, suggesting a role for hyper-mutation in NoV diversity. To mor…
Spatio-temporal soil drying in southeastern South America: the importance of effective sampling frequency and observational errors on drydown time sc…
2020
The study of the spatio-temporal dynamics of surface soil moisture (SSM) drydowns integrates the soil response to climatic conditions, drainage and land cover and is key to advances in our knowledg...
Ongoing and emerging questions in water erosion studies
2017
51 Pags.- 9 Figs. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-145X
A conspectus of Tephroseris (Asteraceae: Senecioneae) in Europe outside Russia and notes on the decline of the genus
2021
Tephroseris is generally considered a difficult genus. Based on the examination of extensive herbarium material and considering the existing literature, we recognize seven species in Europe outside Russia. These are T. palustris, T. integrifolia with subsp. integrifolia, subsp. aurantiaca, subsp. capitata, subsp. maritima, subsp. serpentini and subsp. “tundricola”, T. balbisiana, T. crispa, T. helenitis, T. longifolia and T. papposa. Phylogenetic analysis of ITS and ETS sequences showed that these species fall into three lineages. These are: (1) T. palustris, clearly related to Arctic species of the genus; (2) T. integrifolia; and (3) the remaining species. Molecular dating of the T. integr…
Quantification of LAI interannual anomalies by adjusting climatological patterns
2011
International audience; Scaling variations and shifts in the timing of seasonal phenology are central features of global change research. In this study, we propose a novel climatology fitting approach to quantify inter-annual anomalies in LAI seasonality. A consistent archive of daily LAI estimates was first derived from historical AVHRR satellite data for the 1981-2000 period over a globally representative sample of sites. The climatology values were then computed by averaging multi-year LAI profiles, gap filling and smoothing to eliminate possible high temporal frequency residual artifacts. The inter-annual variations in LAI were finally quantified by scaling and shifting the seasonal cli…
Agricultural management affects the response of soil bacterial community structure and respiration to water-stress
2013
International audience; Soil microorganisms are responsible for organic matter decomposition processes that regulate soil carbon storage and mineralisation to CO2. Climate change is predicted to increase the frequency of drought events, with uncertain consequences for soil microbial communities. In this study we tested the hypothesis that agricultural management used to enhance soil carbon stocks would increase the stability of microbial community structure and activity in response to water-stress. Soil was sampled from a long-term field trial with three soil carbon management systems and was used in a laboratory study of the effect of a dry wet cycle on organic C mineralisation and microbi…
The future of temporary wetlands in drylands under global change
2021
The Andalusian International University held a workshop entitled Temporary wetlands’ future in drylands under the projected global change scenario in March 2020 in Baeza, Spain, with 26 participants from 10 countries. The workshop objectives were to promote international cooperation and scientific exchange on the conservation and protection of temporary wetlands. The participants highlighted the extreme conditions that temporary and permanent wetlands, ponds, and shallow lakes are currently facing and predicted a dismal future for these systems due to climate change. To foster a holistic view of these ecosystems, the workshop included wetland watersheds. It was concluded that the main threa…
Late Cretaceous continental weathering evolution on the southern Atlantic margins of Africa and South America : contributions of a new geochemical tr…
2022
The late Cretaceous records a pronounced decrease in temperatures on a global scale between 90 and 65 million years that marks the first step of the progressive climatic decline ultimately leading to our modern climate mode. This first cooling step is concomitant to a major tectonic uplift of the east South American and west African margins. Relief formation on the African ans South American continent, enhancing continental weathering, can have induced a climatic cooling at a global scale through atmospheric CO2 consumption linked to silicate weathering reactions. The main objective of this project is to explore the potentially determinant impact of this tectonic uplift on the long-term coo…
Distribution of clay minerals in Early Jurassic Peritethyan seas: palaeoclimatic significance inferred from multiproxy comparisons.
2009
13 pages; International audience; A set of published, unpublished, and new clay mineral data from 60 European and Mediterranean localities allows us to test the reliability of clay minerals as palaeoclimatic proxies for the Pliensbachian–Toarcian period (Early Jurassic) by reconstructing spatial and temporal variations of detrital fluxes at the ammonite biochronozone resolution. In order to discuss their palaeoclimatic meaning, a compilation of low-latitude belemnite δ18O, δ13C, Mg/Ca, and 87Sr/86Sr values is presented for the first time for the whole Pliensbachian– Toarcian period. Once diagenetic and authigenic biases have been identified and ruled out, kaolinite content variation is cons…
Segmentation and differential post-rift uplift at the Angola margin as recorded by the transform-rifted Benguela and oblique-to-orthogonal-rifted Kwa…
2010
29 pages; International audience; We analyse tectonic and sedimentary field and subsurface data for the Angola onshore margin together with free-air gravity anomaly data for the offshore margin. This enables us to characterize the mode of synrift tectonism inherited from the Precambrian and its impact on the segmentation of the Angola margin. We illustrate that segmentation by the progressive transition from the Benguela transform-rifted margin segment to the oblique-rifted South Kwanza and orthogonal-rifted North Kwanza margin segments. The spatial variation in the intensity of post-rift uplift is demonstrated by the study of a set of geomorphic markers detected in the post-rift succession…