| 31. |
- Pilla, Rachel M., et al.
(author)
-
Global data set of long-term summertime vertical temperature profiles in 153 lakes
- 2021
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In: Scientific Data. - : Springer Nature. - 2052-4463. ; 8:1
-
Journal article (peer-reviewed)abstract
- Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends in full vertical thermal structure and deepwater temperatures, which have been changing less consistently in both direction and magnitude. Here, we present a globally-expansive data set of summertime in-situ vertical temperature profiles from 153 lakes, with one time series beginning as early as 1894. We also compiled lake geographic, morphometric, and water quality variables that can influence vertical thermal structure through a variety of potential mechanisms in these lakes. These long-term time series of vertical temperature profiles and corresponding lake characteristics serve as valuable data to help understand changes and drivers of lake thermal structure in a time of rapid global and ecological change.
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| 32. |
- Pilotto, Francesca, et al.
(author)
-
Meta-analysis of multidecadal biodiversity trends in Europe
- 2020
-
In: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1
-
Journal article (peer-reviewed)abstract
- Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15-91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe. The global biodiversity decline might conceal complex local and group-specific trends. Here the authors report a quantitative synthesis of longterm biodiversity trends across Europe, showing how, despite overall increase in biodiversity metric and stability in abundance, trends differ between regions, ecosystem types, and taxa.
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| 33. |
- Richards, Stephen, et al.
(author)
-
Genome Sequence of the Pea Aphid Acyrthosiphon pisum
- 2010
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In: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:2, s. e1000313-
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Journal article (peer-reviewed)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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| 34. |
- Sawcer, Stephen, et al.
(author)
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Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
- 2011
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 476:7359, s. 214-219
-
Journal article (peer-reviewed)abstract
- Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.
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| 35. |
- Sharma, Sapna, et al.
(author)
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A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009
- 2015
-
In: Scientific Data. - : Macmillan Publishers Limited. - 2052-4463. ; 2
-
Journal article (peer-reviewed)abstract
- Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.
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| 36. |
- Singh, Vinayak, et al.
(author)
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Identification of aminopyrimidine-sulfonamides as potent modulators of Wag31-mediated cell elongation in mycobacteria.
- 2017
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In: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 103:1, s. 13-25
-
Journal article (peer-reviewed)abstract
- There is an urgent need to discover new anti-tubercular agents with novel mechanisms of action in order to tackle the scourge of drug-resistant tuberculosis. Here, we report the identification of such a molecule - an AminoPYrimidine-Sulfonamide (APYS1) that has potent, bactericidal activity against M. tuberculosis. Mutations in APYS1-resistant M. tuberculosis mapped exclusively to wag31, a gene that encodes a scaffolding protein thought to orchestrate cell elongation. Recombineering confirmed that a Gln201Arg mutation in Wag31 was sufficient to cause resistance to APYS1, however, neither overexpression nor conditional depletion of wag31 impacted M. tuberculosis susceptibility to this compound. In contrast, expression of the wildtype allele of wag31 in APYS1-resistant M. tuberculosis was dominant and restored susceptibility to APYS1 to wildtype levels. Time-lapse imaging and scanning electron microscopy revealed that APYS1 caused gross malformation of the old pole of M. tuberculosis, with eventual lysis. These effects resembled the morphological changes observed following transcriptional silencing of wag31 in M. tuberculosis. These data show that Wag31 is likely not the direct target of APYS1, but the striking phenotypic similarity between APYS1 exposure and genetic depletion of Wag31 in M. tuberculosis suggests that APYS1 might indirectly affect Wag31 through an as yet unknown mechanism.
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| 37. |
- Sommer, Ulrich, et al.
(author)
-
Beyond the Plankton Ecology Group (PEG) Model : Mechanisms Driving Plankton Succession
- 2012
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In: Annual Review of Ecology, Evolution and Systematics. - : Annual Reviews. - 1543-592X .- 1545-2069. ; 43, s. 429-448
-
Research review (peer-reviewed)abstract
- The seasonal succession of plankton is an annually repeated process of community assembly during which all major external factors and internal interactions shaping communities can be studied. A quarter of a century ago, the state of this understanding was described by the verbal plankton ecology group (PEG) model. It emphasized the role of physical factors, grazing and nutrient limitation for phytoplankton, and the role of food limitation and fish predation for zooplankton. Although originally targeted at lake ecosystems, it was also adopted by marine plankton ecologists. Since then, a suite of ecological interactions previously underestimated in importance have become research foci: overwintering of key organisms, the microbial food web, parasitism, and food quality as a limiting factor and an extended role of higher order predators. A review of the impact of these novel interactions on plankton seasonal succession reveals limited effects on gross seasonal biomass patterns, but strong effects on species replacements.
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| 38. |
- Sommer, Ulrich, et al.
(author)
-
The response of temperate aquatic ecosystems to global warming : novel insights from a multidisciplinary project
- 2012
-
In: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 159:11, s. 2367-2377
-
Research review (peer-reviewed)abstract
- This article serves as an introduction to this special issue of Marine Biology, but also as a review of the key findings of the AQUASHIFT research program which is the source of the articles published in this issue. AQUASHIFT is an interdisciplinary research program targeted to analyze the response of temperate zone aquatic ecosystems (both marine and freshwater) to global warming. The main conclusions of AQUASHIFT relate to (a) shifts in geographic distribution, (b) shifts in seasonality, (c) temporal mismatch in food chains, (d) biomass responses to warming, (e) responses of body size, (f) harmful bloom intensity, (f), changes of biodiversity, and (g) the dependence of shifts to temperature changes during critical seasonal windows.
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| 39. |
- Stelzer, Julio Alberto Alegre, et al.
(author)
-
Early warning signals of regime shifts for aquatic systems : Can experiments help to bridge the gap between theory and real-world application?
- 2021
-
In: Ecological Complexity. - : Elsevier. - 1476-945X .- 1476-9840. ; 47
-
Journal article (peer-reviewed)abstract
- Early-warning signals of a regime shift (EWS) indicate, for a wide range of systems, if a tipping-point is being approached. In ecology, EWS are well established from a theoretical perspective but are far from unequivocal when applied to field data. The gap between theory and application is caused by a set of limitations, like the lack of coherence between different EWS, data acquisition issues, and false results. Experiments assessing EWS may provide an empirical mechanistic understanding of why an EWS was observed (or failed to be observed), which often cannot be elucidated by simple computational modeling or pure environmental data. Here we focused on aquatic experiments to explore to what extent the existing EWS experiments can bridge the gap between the theory and real-world application. For that, we used the Thomson-ISI Web of Science (c) database to retrieve EWS experiments executed before early-2020, detailing their experimental designs and each EWS assessed. Success rates - correct anticipation of tipping points - were around 70% for the most used EWS (assessment of autocorrelation, variance, recovery, and shape of the distribution using abundance, Chlorophyll-a, Phycocyanin, and dissolved oxygen data). Yet, no EWS showed to be 100% reliable, and their use demands cautious interpretation. As a rule, we observed that experiments were not designed to tackle issues encountered in real-world situations. They lack a deep mechanistic understanding of why, when, and how an EWS was observed or not. When experiments did aim to assess issues encountered in the real world, the experimental designs were often of low ecological significance. We also investigated the relationship between sampling and the success rate of EWS, observing that the sampling regime might have to be tailor-made towards specific monitoring objectives. Moreover, experiments have taught us that the use of EWS can be more versatile than expected, going from monitoring the extinction of single populations to the anticipation of transient regime shifts. Most of the experiments presented here supported empirical proof of the existence of EWS in aquatic systems. Still, to bridge the gap between theory and application, experiments will have to move closer to real-world conditions and better support a mechanistic understanding of why EWS may succeed or fail to anticipate a regime shift. For that, we provide six elements to take into account when designing experiments that could enhance the capabilities of EWS to go beyond the stage of proof-of-concept.
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| 40. |
- Stelzer, Julio A. A., et al.
(author)
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Phytoplankton responses to repeated pulse perturbations imposed on a trend of increasing eutrophication
- 2022
-
In: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 12:3
-
Journal article (peer-reviewed)abstract
- While eutrophication remains one of the main pressures acting on freshwater ecosystems, the prevalence of anthropogenic and nature-induced stochastic pulse perturbations is predicted to increase due to climate change. Despite all our knowledge on the effects of eutrophication and stochastic events operating in isolation, we know little about how eutrophication may affect the response and recovery of aquatic ecosystems to pulse perturbations. There are multiple ways in which eutrophication and pulse perturbations may interact to induce potentially synergic changes in the system, for instance, by increasing the amount of nutrients released after a pulse perturbation. Here, we performed a controlled press and pulse perturbation experiment using mesocosms filled with natural lake water to address how eutrophication modulates the phytoplankton response to sequential mortality pulse perturbations; and what is the combined effect of press and pulse perturbations on the resistance and resilience of the phytoplankton community. Our experiment showed that eutrophication increased the absolute scale of the chlorophyll-a response to pulse perturbations but did not change the proportion of the response relative to its pre-event condition (resistance). Moreover, the capacity of the community to recover from pulse perturbations was significantly affected by the cumulative effect of sequential pulse perturbations but not by eutrophication itself. By the end of the experiment, some mesocosms could not recover from pulse perturbations, irrespective of the trophic state induced by the press perturbation. While not resisting or recovering any less from pulse perturbations, phytoplankton communities from eutrophying systems showed chlorophyll-a levels much higher than non-eutrophying ones. This implies that the higher absolute response to stochastic pulse perturbations in a eutrophying system may increase the already significant risks for water quality (e.g., algal blooms in drinking water supplies), even if the relative scale of the response to pulse perturbations between eutrophying and non-eutrophying systems remains the same.
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