Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
50
datasets available to search
ShareScore release 0.9.0
Dataset results
50 results for “Nitrogen fixing”
Data for: Dissolved organic matter (DOM) offsets the detrimental effects of climate change in the nitrogen fixing cyanobacterium Crocosphaera
<div> <div> <div> <div> <p>Diazotrophs provide a significant reactive nitrogen source in the ocean. Increased warming and stratification may decrease nutrient availability in the future, forcing microbial communities to use dissolved organic matter (DOM). Not depending on reactive nitrogen availability, diazotrophs may be "winners" in a nutrient depleted ocean. However, their ability to exploit DOM may influence this success. We exposed cultures of the widespread <em>Crocosphaera</em> to low (26°C, pH 8.1), moderate (28°C, pH 8.0), and extreme (30°C, pH 7.9) climate change scenarios, under control or DOM-amended conditions. Growth was suboptimal in the low and extreme treatments, and favoured in the moderate treatment. DOM was preferred as a carbon source regardless of the treatment, and promoted N<sub>2</sub> fixation in extreme conditions. This was reflected in the increased expression of photosynthesis genes to obtain energy. DOM provides <em>Crocosphaera</em> with a key ecological advantage, possibly dictating diazotroph-derived nitrogen inputs in the future ocean.</p> </div> </div> </div> </div>
Figure 2 in Nitrogen-fixing Cyanothece sp. as a mixotroph and silver nanoparticle synthesizer: a multitasking exceptional cyanobacterium
Figure 2. Disc inhibition zone against MRSA Staphylococcus aureus using (a) gold nanoparticles, (b) silver nanoparticles, and (c) both silver nanoparticles and gold nanoparticles.
Data for: Dissolved organic matter (DOM) offsets the detrimental effects of climate change in the nitrogen fixing cyanobacterium Crocosphaera
Open the record for dataset details and reuse information.
Data from: Symbioses with nitrogen-fixing bacteria: nodulation and phylogenetic data across legume genera
How species interactions shape global biodiversity and influence diversification is a central – but also data-hungry – question in evolutionary ecology. Microbially-based mutualisms are widespread and could cause diversification by ameliorating stress and thus allowing organisms to colonize and adapt to otherwise unsuitable habitats. Yet the role of these interactions in generating species diversity has received limited attention, especially across large taxonomic groups. In the massive angiosperm family Leguminosae, plants often associate with root-nodulating bacteria that ameliorate nutrient stress by fixing atmospheric nitrogen. These symbioses are ecologically-important interactions, influencing community assembly, diversity, and succession, contributing ~100-290 million tons of N annually to natural ecosystems, and enhancing growth of agronomically-important forage and crop plants worldwide. In recent work attempting to determine whether mutualism with N-fixing bacteria led to increased diversification across legumes, we were unable to definitively resolve the relationship between diversification and nodulation. We did, however, succeed in compiling a very large searchable, analysis-ready database of nodulation data for 749 legume genera (98% of Leguminosae genera; LPWG 2017), which, along with associated phylogenetic information, will provide a valuable resource for future work addressing this question and others. For each legume genus, we provide information about the species richness, frequency of nodulation, subfamily association, and topological correspondence with an additional data set of 100 phylogenetic trees curated for database compatibility. We found 386 legume genera were confirmed nodulators (i.e., all species examined for nodulation nodulated), 116 were non-nodulating, 4 were variable (i.e., containing both confirmed nodulators and confirmed non-nodulators), and 243 had not been examined for nodulation in published studies. Interestingly, data exploration revealed that nodulating legume genera are ~3× more species-rich than non-nodulating genera, but we did not find evidence that this difference in diversity was due to differences in net diversification rate. Our metadata file describes in more detail the structure of these data that provide a foundational resource for future work as more nodulation data become available, and as greater phylogenetic resolution of this ca. 19,500-species family comes into focus.
Data from: Do impacts of an invasive nitrogen-fixing shrub on Douglas-fir and its ectomycorrhizal mutualism change over time following invasion?
1. Impacts of invasive species may change in magnitude and even direction with invasion age. Impacts could increase as the population increases, individuals grow in size, and ecological changes accumulate. 2. We used a chronosequence approach to characterize the development of soil impacts over time following the invasion of Cytisus scoparius, a widespread nitrogen-fixing shrub thought to limit reforestation success. In a greenhouse experiment, we evaluated how abundance of ectomycorrhizal fungi, Douglas-fir performance, and leaf nitrogen changed across a 3-31 year chronosequence of invasion. Each of the chronosequence sites were clearcuts where reforestation efforts were unsuccessful and where C. scoparius invaded. To estimate the contributions of the invasion separately from contributions of the accompanying disturbance, i.e. deforestation, we included soils from both invaded and uninvaded patches in each site of the chronosequence. In a complementary soil conditioning experiment, we examined the separate effects of host absence and invader presence on the mycorrhizal mutualism, leaf nitrogen, and seedling growth. 3. Ectomycorrhizal colonization was lower in invaded soil, but this effect did not intensify with time. Despite the suppression of the mutualism, Douglas-fir grew larger in invaded soils. This positive response is likely due to nitrogen fertilization, a conclusion supported by higher concentrations of leaf nitrogen of Douglas-fir grown in invaded soils. While leaf N concentration increased with invasion duration, Douglas-fir survival and growth did not. Synthesis. Our findings suggest that soil impacts of an invader can develop rapidly and can be surprisingly stable over time. In such systems, recently invaded areas may be as difficult to restore as long invaded areas, especially where ectomycorrhizal fungi are important drivers of reforestation success. More chronosequence studies or long time series are needed to evaluate whether this is a general pattern.
Data from: Ecological genomics of mutualism decline in nitrogen-fixing bacteria
Anthropogenic changes can influence mutualism evolution; however, the genomic regions underpinning mutualism that are most affected by environmental change are generally unknown, even in well-studied model mutualisms like the interaction between legumes and their nitrogen (N)-fixing rhizobia. Such genomic information can shed light on the agents and targets of selection maintaining cooperation in nature. We recently demonstrated that N-fertilization has caused an evolutionary decline in mutualistic partner quality in the rhizobia that form symbiosis with clover. Here population genomic analyses of N-fertilized versus control rhizobium populations indicate that evolutionary differentiation at a key symbiosis gene region on the symbiotic plasmid (pSym) contributes to partner quality decline. Moreover patterns of genetic variation at selected loci were consistent with recent positive selection within N-fertilized environments, suggesting that N-rich environments might select for less-beneficial rhizobia. By studying the molecular population genomics of a natural bacterial population within a long-term ecological field experiment, we find that: 1) the N environment is indeed a potent selective force mediating mutualism evolution in this symbiosis, 2) natural variation in rhizobium partner quality is mediated in part by key symbiosis genes on the symbiotic plasmid, and 3) differentiation at selected genes occurred in the context of otherwise recombining genomes, resembling eukaryotic models of adaptation.
Testing TOMRES rootstocks and their efficiency to utilize biologically fixed nitrogen coming from legumes green manure
<p>This experiment was established to test a promising TOMRES variety cultivated under organic and conventional crop system and test different rootstocks coming from the TOMRES collection. In the organic treatment, legumes were pre-cultivated before the tomato crop and were incorporated in soil as green manure. Worms were also applied in the crop to test their ability to increase yield and wue in tomato crop.</p>
Data for: Phosphorus limitation of early growth differs between nitrogen-fixing and non-fixing dry tropical forest tree species
<p>Tropical forests are often characterized by low soil phosphorus (P) availability, suggesting that P limits plant performance. However, how seedlings from different functional types respond to soil P availability is poorly known but important for understanding and modeling forest dynamics under changing environmental conditions.</p> <p>We grew four nitrogen (N)-fixing Fabaceae and seven diverse non-N-fixing tropical dry forest tree species in a shade house under three P fertilization treatments, and evaluated carbon (C) allocation responses, P demand, P-use, investment in P acquisition traits, and correlations among P acquisition traits.</p> <p>N-fixers grew larger with increasing P addition in contrast to non-N-fixers, which showed fewer responses in C allocation and P-use. Foliar P increased with P addition for both functional types, while P acquisition strategies did not vary among treatments but differed between functional types, with N-fixers showing higher root phosphatase activity (RPA) than non-fixers.</p> <p>Growth responses suggest that N-fixers are limited by P, but non-fixers may be limited by other resources. However, regardless of limitation, P acquisition traits such as mycorrhizal colonization and RPA were non-plastic across a steep P gradient. Differential limitation among plant functional types has implications for forest succession and earth system models.</p>
Data from: Nitrogen fixing organelle in a marine alga
Open the record for dataset details and reuse information.
Data from: Symbioses with nitrogen-fixing bacteria: nodulation and phylogenetic data across legume genera
Open the record for dataset details and reuse information.
Data from: Ecological genomics of mutualism decline in nitrogen-fixing bacteria
Open the record for dataset details and reuse information.
Data for: Phosphorus limitation of early growth differs between nitrogen-fixing and non-fixing dry tropical forest tree species
Open the record for dataset details and reuse information.
Data from: Nitrogen fixation and fertilization have similar effects on biomass allocation in nitrogen-fixing plants
Open the record for dataset details and reuse information.
Data from: Do impacts of an invasive nitrogen-fixing shrub on Douglas-fir and its ectomycorrhizal mutualism change over time following invasion?
Open the record for dataset details and reuse information.
Nitrogen fertilization nullifies host sanctions against non-fixing rhizobia and drives divestment from symbiosis in Lotus japonicus
Open the record for dataset details and reuse information.
Negative trait-based association between abundance of nitrogen fixing trees and long-term tropical forest biomass accumulation
<p>1. Plant functional traits are thought to drive biomass production and biogeochemical cycling in tropical forests, but it remains unclear how nitrogen (N)-fixing legumes influence the functional traits of neighboring trees and forest-wide biomass dynamics. Further, the degree to which effects of N-fixers are density-dependent and may depend on stem size and spatial scale remain largely unknown.</p> <p>2. Here, we examine 30-years of stem demography data for ~20,000 trees in a lowland tropical forest in Trinidad that span a wide range of functional traits thought to drive aboveground biomass (AGB) dynamics.</p> <p>3. These forests show positive but decreasing long-term net AGB accumulation resulting from constant average productivity but increasing mortality of non-fixing trees over time. We find that high abundance of N-fixing trees is associated with compositional shifts in non-fixer functional traits that confer lower competitive performance and biomass accumulation. Across tree size classes, most interactions between N-fixers and non-fixers were negative, density dependent, and strongest at smaller spatial scales.</p> <p>4. Synthesis. Overall, our findings suggest that local trait-based interactions between N-fixing and non-fixing trees can influence long-term carbon accumulation in tropical forests.</p>
Data from: Larger plants promote a greater diversity of symbiotic nitrogen-fixing soil bacteria associated with an Australian endemic legume
A major goal in microbial ecology is to understand the factors that structure bacterial communities across space and time. For microbes that are plant symbionts, community assembly processes can lead to either a positive or negative relationship between plant size or age and soil microbe diversity. Here, we evaluated the extent to which such relationships exist within a single legume species (Acacia acuminata) and their naturally occurring symbiotic nitrogen-fixing bacteria (rhizobia). 2. We quantified the diversity of rhizobia that associate with A. acuminata trees of variable size spanning a large environmental gradient in southwest Australia (72 trees in 24 sites spread across ~300,000 km2), using metabarcoding. We modelled rhizobia diversity using 16S exact genetic variants, in a binomial multivariate statistical framework that controlled for climate and local soil characteristics. 3. We identified two major phylogenetic clades of rhizobia that associate with A. acuminata. Soil sampled at the base of larger Acacia trees contained a higher richness of rhizobia genetic variants. Each major clade responds differently to environmental factors (climate and soil characteristics), but the positive association between tree size and rhizobia genetic diversity was mainly driven by responses from one of the two clades. Overall tree size explained more variation than any other factor, resulting in a ~3-fold increase in total richness and clade diversity from the smallest to the largest trees. 4. Synthesis. Previous studies have shown that plant host species is important in structuring microbial soil communities in the rhizosphere. Our results show that host size or age within a single plant species can also structure diversity of at least one group of soil microbes. A positive relationship between plant host size and rhizobia diversity suggests that hosts may modify the niche space of their surrounding soil (niche construction hypothesis) enabling a higher richness of microbial taxa. That different rhizobial groups responded differently to host size and other ecological factors suggests that rhizobia is not an ecologically uniform group, and that entirely neutral explanations for our results are unlikely. Host plants may be analogous to 'islands', where larger plant hosts may accumulate diversity over time, through migration opportunities.
The pan-epigenome of the symbiotic nitrogen fixing bacterium Sinorhizobium meliloti unravels unexpected variability of DNA-methylation profiles in closely related strains
<p>Supplementary Dataset S1. Genome coverage data and assignment of contigs to <em>S. meliloti</em> 1021 genome replicons. MS Excel file format (.xlsx file)</p> <p>Supplementary Dataset S2. Folder containing summary pangenome statistics, core and accessory orthologs, alignments and R script. Zip archive</p> <p>Supplementary Dataset S3. Number motifs and methylated motifs identified and their ratio. Data on number of motifs (RAW), number of methylated motifs (METH), fraction of methylated motifs (RATIO) related to functional features (CDSid, tIG and US sequences) and to replicons (CHR, chromosome; PA, pSymA; PB, pSymB and other) are reported. Red color in columns from “other” indicate missing data (i.e., absence of replicons other than chromosome, pSymA, pSymB). .xlsx file</p>
Data for: Allometric relationships for eight species of 4–5 year old nitrogen-fixing and non-fixing trees
<p>Allometric equations are often used to estimate plant biomass allocation to different tissue types from easier-to-measure quantities. Biomass allocation, and thus allometric equations, often differs by species and sometimes varies with nutrient availability. We measured biomass components for five nitrogen-fixing tree species (<em>Robinia pseudoacacia</em>, <em>Gliricidia sepium</em>, <em>Casuarina equisetifolia</em>, <em>Acacia</em> <em>koa</em>, <em>Morella</em> <em>faya</em>) and three non-fixing tree species (<em>Betula nigra, Psidium cattleianum, Dodonaea viscosa</em>) grown in field sites in New York and Hawaii for 4–5 years and subjected to four fertilization treatments. We measured total aboveground biomass, foliar biomass, main stem biomass, secondary stem biomass, and twig biomass in all species, and belowground biomass in <em>Robinia</em> <em>pseudoacacia</em> and <em>Betula</em> <em>nigra</em>, along with basal diameter, height, and canopy dimensions. The individuals spanned a wide size range (<1 to 16 cm basal diameter and 0.24 to 8.8 m height). For each biomass component, aboveground biomass, belowground biomass, and total biomass, we determined the following four allometric equations: the most parsimonious (lowest AIC) overall, the most parsimonious without a fertilization effect, the most parsimonious without canopy dimensions, and an equation with basal diameter only. For some species, the most parsimonious overall equation included fertilization effects, but fertilization effects were inconsistent across fertilization treatments. We therefore concluded that fertilization does not clearly affect allometric relationships in these species, size classes, and growth conditions. Our best-fit allometric equations without fertilization effects had the following R<sup>2</sup> values: 0.91–0.99 for aboveground biomass (the range is across species), 0.95 for belowground biomass, 0.80–0.96 for foliar biomass, 0.94–0.99 for main stem biomass, 0.77–0.98 for secondary stem biomass, and 0.88–0.99 for twig biomass. Our equations can be used to estimate overall biomass and biomass of tissue components for these size classes in these species, and our results indicate that soil fertility does not need to be considered when using allometric relationships for these size classes in these species.</p>
Data for: Allometric relationships for eight species of 4–5 year old nitrogen-fixing and non-fixing trees
Open the record for dataset details and reuse information.
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.