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141 results for “isotopic composition”
Figure 3 in Variations in trophic niches of generalist predators with plant community composition as indicated by stable isotopes and fatty acids
Figure 3. Principal components analysis of the relative abundance (mol %, logit-transformed) of individual NLFAs of Harpalus rufipes using flooding index (FI), plant species richness (SR), plant functional group richness (FG), presence of grasses (Gr), legumes (Leg), small herbs (SH) and tall herbs (TH) as supplementary variables.
Figure 6 in Variations in trophic niches of generalist predators with plant community composition as indicated by stable isotopes and fatty acids
Figure 6. Principal components analysis of the relative abundance (mol%, logit- transformed) of individual PLFAs of soil microorganisms using flooding index (FI), plant species richness (SR), plant functional group richness (FG), presence of grasses (Gr), legumes (Leg), small herbs (SH) and tall herbs (TH) as supplementary variables.
Figure 2 in Variations in trophic niches of generalist predators with plant community composition as indicated by stable isotopes and fatty acids
Figure 2. Variations in δ15N signatures of Harpalus rufipes (P <0.01, R2 = 0.11) as affected by plant species richness (log-transformed).
Multi-year dataset for groundwater level, temperature, and chemical and isotopic compositions of different water bodies in an alpine catchment on the northeastern Qinghai-Tibet Plateau, China
<p>Here we provide the multi-year dataset for groundwater level, temperature, and chemical and isotopic compositions of different water bodies in an alpine catchment on the northeastern Qinghai-Tibet Plateau, China. The first file contains monitoring data, including groundwater levels and ground temperatures. The second file includes the results of the sample analyses as well as the numbers and locations of the sampling sites.</p>
Observed and Predicted Bulk Sediment Uranium Isotope Composition (δ234U) for ODP 1094 Over the Last 500 kyr
<p>This is supplementary data associated with a manuscript entitled "Anomalous 234U/238U Isotopic Composition in Southern Ocean Sediments" by N. Redmond, C. T. Hayes, S. K. Glasscock, E. Rohde, R. F. Anderson, and D. McGee</p> <p><br> Variables<br> Sample ID - Section of ODP 1094 core. Hole-Core-Section-Depth(cms)<br> MCD_TOP - Meters Composite Depth at the top of the section<br> Age (Hasenfratz et al., 19) - in kyrs, based on tuning of benthic δ18O to LR04 stack<br> U-238 - Concentration of 238U in bulk sediment, units in ppm or micrograms/gram.<br> aU - Authigenic uranium concentration, calculated from removing th-based detrital U fraction from bulk 238U, units in ppm or micrograms/gram<br> δ234U Observed - Uranium isotope composition observed in bulk sediment, written as the per mil deviation from secular equilibrium, units in ppm or micrograms/gram<br> δ234U Observed Error - Uncertainty Uranium isotope composition observed in bulk sediment, written as the per mil deviation from secular equilibrium, units in ppm or micrograms/gram<br> δ234U Modeled - Uranium isotope composition predicted in bulk sediment by a mixing model of authigenic and detrital U, decayed with age to match observed data, written as the per mil deviation from secular equilibrium, units in ppm or micrograms/gram<br> δ234U Modeled Error - Uncertainty of Uranium isotope composition predicted in bulk sediment by a mixing model of authigenic and detrital U, decayed with age to match observed data, written as the per mil deviation from secular equilibrium, units in ppm or micrograms/gram</p> <p> </p>
Water isotopic composition (Oxygen-18 and Deuterium) from the EPICA Dome C ice core at 11 cm resolution
<p>This manuscript presents a compilation of high resolution (11 cm) water isotopic records including published and new measurements over the last 800 000 years on the EPICA Dome C ice core, Antarctica. Using this new water isotopes (δ18O and δD) combined dataset, we study the variability and possible influence of diffusion at multi-decadal to multi-centennial scale. We observe a stronger variability on the onset of the interglacial interval corresponding to a warm period.</p>
Diet composition based on stable isotopic analysis of fecal samples revealed the preference of Black-faced Spoonbill (Platalea minor) for natural wetlands and fishponds
<p><span>Background:</span><span> Black-faced spoonbill (BFS) is a global endangered species, distributed only in the coastal zones of East Asia. Xinghua Bay is one of the main wintering sites and migration stopovers of BFS in mainland China. However, </span><span>with the </span><span>reduction and degradation of natural wetlands, it is uncertain whether the constructed wetland can provide habitat for the endangered BFS. Research on diet of BFS will help to understand their preference between natural and artificial wetlands, and also provide reference for their conservation and habitat restoration. </span></p> <p><span>Results:</span><span> In the early winter, the proportion of Palaemonidae in BFS's food was as high as 74.4%, while that of other food was only 3.0% to 6.0%. In the late winter, the food contribution of BFS was as follow: Portunidae </span><span>39.3% </span><span>> Palaemonidae </span><span>26.1% </span><span>> Cyprinidae </span><span>8.8% </span><span>></span> <span>Mugilidae </span><span>8.5% </span><span>> Gobiidae </span><span>7.3% </span><span>></span> <span>Crucian </span><span>5.1% </span><span>> Whiteshrimp </span><span>4.8%</span><span>. The proportion of Portunidae exceeded that of Palaemonidae, and together with Palaemonidae, it has become the main food of BFS in late winter. </span></p> <p><span>Conclusion: </span><span>The diet composition of BFS between the early and late winter was significantly different, which may be due to seasonal changes in food resources. Natural wetlands are the main feeding grounds of BFS, but artificial wetlands also provide them with supplementary feeding grounds and resting places. Aquaculture ponds play an important ecological function in maintaining the overwintering population of BFS in Xinghua Bay.</span></p>
Can diet composition estimates using stable isotope analysis of feathers predict growth and condition in nestling mountain bluebirds (Sialia currucoides)
<p>Insectivorous birds breeding in seasonal environments provision their dependent young during periods when prey diversity and abundance vary. Consequently, the composition and nutritional value of diets parents feed to their offspring may differ within and among broods, potentially affecting the condition of nestlings. In a population of mountain bluebirds (<i>Sialia currucoides</i>), we used two methods to estimate diet composition for individual nestlings: direct observation of provisioning using video recordings at 5 and 9 days post-hatch, and stable isotopes of the δ<sup>13</sup>C and δ<sup>15</sup>N in nestling feathers and prey followed by analysis with mixing models. We determined the macronutrient content (% fat and lean mass) and estimated the metabolized energy from each type of prey. We evaluated whether different methods of estimating diet composition would produce similar results, and if the types of prey nestlings ate at one or both ages affected their morphology, growth rates, or blood ketone concentration. We found that bluebirds fed their young 5 main types of prey: beetles, cicadas, grasshoppers, insect larvae, and spiders. Both observational and mixing model estimates of diet composition indicated that larvae are traded-off with grasshoppers, and that fewer larvae are provided to nestlings as the season progresses. In evaluating how diet influences individual growth and condition, estimates from direct observations had greater explanatory power than those from mixing models, indicating that diets rich in the most energy-dense prey (greatest fat content; cicadas and larvae) were associated with larger size and higher body condition, and faster rate of mass gain and growth of tarsus. Lower value prey had more limited, specific effects on nestlings, but may still be important dietary components. While isotopic methods produced estimates of diet composition that were generally informative, when applied to explain the growth and condition of nestlings they proved less useful. </p>
Data archive: Trophic structure of cold-water coral communities revealed from the analysis of tissue isotopes and fatty acid composition
<p>Data belonging to the paper: </p> <p>Dick van Oevelen, Gerard C. A. Duineveld, Marc S. S. Lavaleye, Tina Kutti and Karline Soetaert (2017) Trophic structure of cold-water coral communities revealed from the analysis of 55 tissue isotopes and fatty acid composition. Marine Biology Research, DOI: https://doi.org/10.1080/17451000.2017.1398404</p> <p>Abstract:</p> <p>The trophic structure of cold-water coral reef communities at two contrasting locations, the 800-<br> m deep Belgica Mounds (Irish margin) and 300-m deep Træna reefs (Norwegian Shelf), was<br> investigated using stable isotope (δ13C and δ15N) and fatty-acid composition analysis. A<br> broad range of specimens, with emphasis on (commercial) fish species, and organic matter<br> sources were sampled using a variety of tools. Irrespective of the environmental and<br> geographical setting, the δ15N values indicated that the food web encompasses roughly 1.5<br> to 3 trophic levels. Mobile echinoderms, i.e. sea urchins and sea stars, had highest δ15N<br> values, indicative of a high trophic position in the food web. The fraction of bacterial fatty<br> acids in reef fauna was generally low (<5%), indicating that enhanced bacterial production in<br> the water column through seafloor seepage of nutrients (‘hydraulic theory’) does not form a<br> significant energy pathway into the food web. The high fraction of algal and essential fatty<br> acids in reef fauna and fish at both locations indicates a close coupling with surface<br> productivity, but the transport mechanism depends on the hydrographic setting. At Træna,<br> Calanus copepods and euphausiids form an additional link between primary production and<br> fish, which is largely absent at Belgica Mounds. At Belgica Mounds, the reef community is<br> primarily supported by phytodetritus, as evidenced by the high contribution of algal fatty<br> acids in faunal tissue and seasonal chlorophyll a deposition and marine snow at the reef. The<br> environmental setting of cold-water coral reefs influences the structure of the associated<br> food web.</p>
Stable and radiocarbon isotope compositions of DOC and DIC in Southeast Asian drainage canals
<p>This dataset contains the stable and radiocarbon isotope compositions of dissolved organic carbon (DOC) and radiocarbon isotope compositions of dissolved inorganic carbon (DIC) produced during DOC microbial respiration and photomineralization in canal waters sampled across disturbed peatlands in West Kalimantan, Indonesia in 2022. Microbial respiration and photomineralization experiments were carried out during laboratory incubations and natural sunlight exposures of canal water samples, respectively. Significant changes in the radiocarbon isotope composition of DIC between treatment and control waters were detected using a headspace extraction technique followed by a small-carbon extraction line for radiocarbon samples. </p>
Geochemical and isotopic compositions of lake waters, creek and permafrost of Central Yakutia from 2017, 2018 and 2019
<p>The file contains a table of all data of geochemical and isotopic compositions of lake waters, creek and permafrost of Central Yakutia from 2017, 2018 and 2019.</p>
Data for Stable isotope composition of long and short term carbon pools can screen drought tolerance in cassava
<p>This repository contains data and scripts to reproduce results that are presented in the article: Van Laere, J., Martinez Maya, M.A., Selvaraj M.G., Becerra Lopez-Lavalle, L.A., Guzman, D., Casas, J.A., Merckx, R., Hood-Nowotny, R., Dercon, G. (2024)<strong> Stable isotope composition of long and short term carbon pools can screen drought tolerance in cassava</strong>. <em>Field Crops Research. </em>https://doi.org/10.1016/j.fcr.2024.109586</p>
Tropical Peatland Drainage Canal Methane Concentrations, Fluxes, and Isotopic Composition
<p>This dataset contains methane (CH<sub>4</sub>) concentration and <sup>13</sup>C isotope composition (δ<sup>13</sup>C-CH<sub>4</sub>) and environmental variables (canal dimensions, water quality, etc.) from canals draining peatlands in West Kalimantan, Indonesia. The data also contains CH<sub>4</sub> emissions measured using floating chambers and potential CH<sub>4</sub> oxidation rates and associated isotopic fractionation from a subset of studied canals, as well as porewater data from peat soils in the study region. Each data file contains a "README" tab with a guide for variable units and descriptions. </p> <p>File contents: </p> <ul> <li><strong>Canal_CH4_Survey_Perryman.xlsx </strong>= canal water CH<sub>4</sub> concentration and δ<sup>13</sup>C-CH<sub>4</sub> from a synpotic survey of canals in Kubu Raya Regency and Mempawah Regency, West Kalimantan, Indonesia. Data also includes canal properties, water chemistry, and estimates of the fraction of CH4 oxidized and diffusive emissions for each canal</li> <li><strong>Canal_Water_Incubations_Perryman.xlsx</strong> = measurements of dissolved CH<sub>4</sub> concentration and δ<sup>13</sup>C-CH<sub>4</sub> from canal water incubations</li> <li><strong>Floating_Chamber_Flux_Perryman.xlsx</strong> = CH<sub>4</sub> emissions and source δ<sup>13</sup>C-CH<sub>4 </sub>determined from floating chamber deployments on canals</li> <li><strong>Porewater_CH4_Perryman.xlsx </strong>= peatland porewater CH<sub>4</sub> concentration and δ<sup>13</sup>C-CH<sub>4</sub> from 6 profiles collected in the study area</li> </ul>
Elemental and isotopic composition of bronze axes from Léon (France)
<p>This dataset contains analyses of 31 copper-alloy axes from Léon (Landes, France).<br><br><strong>Material</strong></p> <p>31 copper-alloy axes were analyzed. Each artefact was weighed, photodocumented, and 3D digitized before sampling. Each artefact was sampled twice using a single-use saw blade. The first sample was taken from the heel of the axes, after which the surface was mechanically cleaned to remove surface corrosion. These samples were used to measure lead isotope ratios. The second sample, a few cubic millimeters in size, was taken from the edge of the blades. These micro-samples were mounted, then ground and polished to a 0.25 mm diamond finish to create a surface suitable for SEM-EDS analyses.</p> <p><strong>Energy dispersive X-ray spectrometry</strong></p> <p>The elemental composition of the samples was obtained by energy-dispersive X-ray fluorescence spectrometry using two Oxford Ultim Max 100 spectrometers, coupled with scanning electron microscopy imaging (JEOL JSM IT500HR variable-pressure microscope). Measurements were carried out under a partial vacuum (20 Pa) with an acceleration voltage of 20 kV to avoid charging phenomena. The acquisition time was 60 seconds per spectrum over the 0-20 keV energy range. For all EDS spectra, the dead time during acquisition was around 30%, with an average number of counts per spectrum greater than 106.</p> <p>Due to the presence of arsenic (As) and lead (Pb) in the same samples, the As L ray series and the Pb M ray series were used for EDS analyses to avoid line overlap with the As K ray series and Pb L ray series. Six measurements were carried out on each sample, with the area analyzed in each measurement being approximately 0.05 mm². For each sample, the compositional mean (Aitchison 1986) of the six measurements was used. Results are expressed as mass percentages, normalized to 100%. Values below 0.5% should be interpreted with caution, but they are retained in the general composition as they provide qualitative information.</p> <p>The file leon_elements.csv contains all elemental compositions, with the following columns:</p> <ul> <li><em>code</em>: sample reference.</li> <li><em>O</em>,<em>Mg</em>,<em>Al</em>,<em>Si</em>,<em>S</em>,<em>Fe</em>,<em>Ni</em>,<em>Cu</em>,<em>Zn</em>,<em>As</em>,<em>Sn</em>,<em>Pb</em>: amounts (%)</li> </ul> <p><strong>Multi-collection mass spectrometry</strong></p> <p>Lead isotope ratios were measured by multi-collection inductively coupled plasma mass spectrometry (MC-ICP-MS) at the Service d'Analyse des Roches et Minéraux (SARM) of the Centre de Recherches Pétrographiques et Géochimiques (UMR 7358 CRPG).</p> <p>Samples were weighed into 15 mL Savillex vial, and HNO3 was added. The solution was heated at 115°C for at least 72 hours, evaporated, then mixed with HCl and heated again for 24 hours or until the sample was completely dissolved. After evaporation, 1 mL of 0.8 M HBr was added to place the sample in the same medium as that used in the ion exchange column.</p> <p>Each sample was loaded onto approximately 50 microliters of AG1X8 resin in micro-columns (see Manhes et al. 1980), then 2 mL of 0.8 M HBr were used for elution. Lead was collected in 2 mL of 6M HCl (4 x 0.5 mL), dried, and redissolved in 1 mL of 0.5 M HNO3.</p> <p>Pb analyses were performed on an MC-ICP-MS (Neptune Plus, Thermo Electron) using Tl (NIST 997) as an external standard for mass bias (White, Albarède, and Télouk 2000). The Tl and Pb values used for NIST 981 are those of Thirlwall (2002).</p> <p>The file leon_isotopes.csv contains all lead isotopes ratios, with the following columns:</p> <ul> <li><em>CRPG</em>, <em>BDX</em>: sample references.</li> <li><em>Pb_206_204</em>, <em>Pb_206_204_error</em>: 206Pb/204Pb ratio and error.</li> <li><em>Pb_207_204</em>, <em>Pb_207_204_error</em>: 207Pb/204Pb ratio and error.</li> <li><em>Pb_208_204</em>, <em>Pb_208_204_error</em>: 208Pb/204Pb ratio and error.</li> <li><em>Pb_207_206</em>, <em>Pb_207_206_error</em>: 207Pb/206Pb ratio and error.</li> <li><em>Pb_206_207</em>, <em>Pb_206_207_error</em>: 206Pb/207Pb ratio and error.</li> <li><em>Pb_208_206</em>, <em>Pb_208_206_error</em>: 208Pb/206Pb ratio and error.</li> </ul>
Shatsky Rise, ODP Sites 1209 and 1210 Maastrichtian composite bulk carbonate stable isotopes, XRF scanning, biogenic barium, and benthic foraminiferal records
<p>A bulk composite carbonate stable isotope, X-ray fluorescence (XRF) scanning (elemental barium), biogenic barium and benthic foraminiferal record in deep sea sediments from the tropical Pacific was produced from 71.5 to 66 million years ago to determine variations in carbon export in the Pacific during the Maastrichtian. The cores were drilled on Shatsky Rise in the tropical Pacific at Ocean Drilling Program (ODP) Leg 198 Sites 1209 and 1210. Method details and interpretation are in the publication.</p>
Nd and Sr isotope compositions of debris from the basal ice of the Byrd ice core, central West Antarctica
<p>This dataset comprises of Nd and Sr isotope compositions of debris melted from three intervals of basal ice from the Byrd ice core. Measurements were performed on the <75 micron fractions, both with and without treatment in a leaching solution designed to remove authigenic coatings, as well as a rhyolite cobble. The ice core the debris was extracted from was drilled at 80<i><strong>°</strong></i> 0.1'S, 119<i><strong>°</strong></i> 31.0'W at Byrd Station, West Antarctica, in January 1968.</p>
Can diet composition estimates using stable isotope analysis of feathers predict growth and condition in nestling mountain bluebirds (Sialia currucoides)
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Diet composition based on stable isotopic analysis of fecal samples revealed the preference of Black-faced Spoonbill (Platalea minor) for natural wetlands and fishponds
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Nitrate Isotopic Composition, Hubbard Brook Experimental Forest, Watershed 3, 2011
Despite decades of measurements, the nitrogen balance of temperate forest catchments remains poorly understood. Atmospheric nitrogen deposition often greatly exceeds streamwater nitrogen losses; the fate of the remaining nitrogen is highly uncertain. Gaseous losses of nitrogen to denitrification are especially poorly documented and are often ignored. Here, we provide isotopic evidence (δ15NNO3 and δ18ONO3) from shallow groundwater at the Hubbard Brook Experimental Forest indicating extensive denitrification during midsummer, when transient, perched patches of saturation developed in hillslopes, with poor hydrological connectivity to the stream, while streamwater showed no isotopic evidence of denitrification. During small rain events, precipitation directly contributed up to 34% of streamwater nitrate, which was otherwise produced by nitrification. Together, these measurements reveal the importance of denitrification in hydrologically disconnected patches of shallow groundwater during midsummer as largely overlooked control points for nitrogen loss from temperate forest catchments. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
Climate Change Across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest: Foliar Nitrogen and Natural Abundance Nitrogen Isotopic Composition
Foliar nitrogen and natural abundance stable isotopes of nitrogen in foliage were measured on all Climate Change Across Seasons Experiment (CCASE) plots. There are six plots total (each 11 x 14 m). Two are warmed 5 degrees C throughout the growing season (Plots 3 and 4). Two others are warmed 5 degrees C in the growing season and have snow removed during winter to induce soil freezing and then warming cables turn on to create thaws; each soil freeze/thaw cycle includes 72-hours of soil freezing followed by 72-hours of thaw (Plots 5 and 6). Four kilometers (2.5 mi) of heating cable are buried in the soil to warm these four plots. Two additional plots serve as controls for our experiment (Plots 1 and 2). This data set includes foliar nitrogen and natural abundance stable isotopes of nitrogen in foliage from 2012 to 2018. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
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