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78 results for “isotope ratio”
C and N stable isotope ratios in fishes from marine protected areas and areas open to fishing
<p><span>Here, we assess </span><span>whether fishery exploitation affects the trophic structure of carnivorous fishes</span><span>. We censused fishes and analysed the stable isotope ratios of C and N of species targeted by fishermen in areas open to fishing and marine protected areas in the Mediterranean Sea and the north-eastern Atlantic Ocean. Results demonstrated a major impact of fishing on the biomass and the size structure of nektobenthic carnivorous fishes. However, those changes did not modify the diversity of the trophic resources used by the assemblage, </span><span>the pattern of resource partitioning between species or the degree of trophic redundancy</span><span>. These results add to recent evidence suggesting that marine protected areas implemented in fished seascapes may fail to restore the original structure of the food webs that once existed in pre-fished ecosystems, because regional decimation and extinction of highly mobile predators prevents recovering the original diversity of predators at local scales, even at no-take areas. If so, more strict local fishing regulations are unlikely to restore the original diversity of high trophic level carnivores and restoration goals should be reframed </span><span>in terms of an objective that is less unrealistic than restoring the pre-fished condition while still recovering aspects of the historical trophic structure</span><span>.</span></p>
Data from: Whiskers provide time-series of toxic and essential trace elements, Se:Hg molar ratios, and stable isotope values of an apex Antarctic predator, the leopard seal
<p>In an era of rapid environmental change and increasing human presence, researchers need efficient tools for tracking contaminants to monitor the health of Antarctic flora and fauna. Here, we examined the utility of leopard seal whiskers as a biomonitoring tool that reconstructs time-series of significant ecological and physiological biomarkers. Leopard seals (<em>Hydrurga leptonyx</em>) are a sentinel species in the Western Antarctic Peninsula due to their apex predator status and top-down effects on several Antarctic species. However, there are few data on their contaminant loads. We analyzed leopard seal whiskers (n = 18 individuals, n = 981 segments) collected during 2018–2019 field seasons to acquire longitudinal profiles of non-essential (Hg, Pb, and Cd) and essential (Se, Cu, and Zn) trace elements, stable isotope (ẟ<sub>15</sub>N and ẟ<sub>13</sub>C) values and to assess Hg risk with Se:Hg molar ratios. Whiskers provided between 46 and 286 cumulative days of growth with a mean ~125 days per whisker (n = 18). Adult whiskers showed variability in non-essential trace elements over time that could partly be explained by changes in diet. Whisker Hg levels were insufficient (<20 ppm) to consider most seals being at "high" risk for Hg toxicity. Nevertheless, maximum Hg concentrations observed in this study were greater than that of leopard seal hair measured two decades ago. However, variation in the Se:Hg molar ratios over time suggest that Se may detoxify Hg burden in leopard seals. Overall, we provide evidence that the analysis of leopard seal whiskers allows for the reconstruction of time-series ecological and physiological data and can be valuable for opportunistically monitoring the health of the leopard seal population and their Antarctic ecosystem during climate change.</p>
Concentrations and isotope ratios of N2O and related substrates with hydrographical data obtained in the eastern Indian Ocean in November, 2018
<p>A spreadsheet that includes data presented in the following publication.</p> <p>Sakae Toyoda, Kotaro Terajima, Naohiro Yoshida, Chisato Yoshikawa, Akiko Makabe, Fuminori Hashihama, and Hiroshi Ogawa, Extensive Accumulation of Nitrous Oxide in the Oxygen Minimum Zone in the Bay of Bengal, Global Biogeochemical Cycles, accepted for publication on August 8, 2023.</p>
Analysis of the occurrence of the fall armyworm (Spodoptera frugiperda) in the winter season on the southwestern islands of Japan using the insect’s strontium radiogenic isotope ratio (87Sr/86Sr)
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Measurements of lead concentrations and isotope ratios of moss and lichens from Portland, Oregon, U.S., and surrounding rural areas
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Enhancing understanding of the hydrological cycle via pairing of process‐oriented and isotope ratio tracers
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Data from: New perspectives on soil animal trophic ecology through the lens of C and N stable isotope ratios of oribatid mites
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Seasonal dynamics of sinking organic matter in the Pacific Arctic Ocean revealed by nitrogen isotope ratios of amino acids
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C and N stable isotope ratios in fishes from marine protected areas and areas open to fishing
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Data from: Whiskers provide time-series of toxic and essential trace elements, Se:Hg molar ratios, and stable isotope values of an apex Antarctic predator, the leopard seal
Open the record for dataset details and reuse information.
McMurdo Dry Valleys Microbial mat biomass, isotopes, and nutrient ratios sampled over a longitudinal gradient of two McMurdo Dry Valley streams
We performed a field survey to assess changes in biomass, nutrient ratios, and isotopic signatures of three different microbial mat types in two glacial meltwater streams in the McMurdo Dry Valleys, Antarctica. Samples were taken in January 2013 from pre-existing transects over Von Guerard Stream and the Relict Channel, and stretched from near the Von Guerard Glacier terminus to the stream outlets at Lake Fryxell. In addition to the three microbial mat types, which included Nostoc (black), Chlorophyte (green), and Oscillatorean (orange) mats, particulate organic matter (POM) was collected from Von Guerard Stream in January 2008 over a full diel cycle in order to determine the origin of material in transport by comparing its elemental and isotopic characteristics with stream mats.
Data from: Photosynthetic pathways in Bromeliaceae: phylogenetic and ecological significance of CAM and C3 based on carbon isotope ratios for 1893 species
A comprehensive analysis of photosynthetic pathways in relation to phylogeny and elevational distribution was conducted in Bromeliaceae, an ecologically diverse Neotropical family containing large numbers of both terrestrial and epiphytic species. Tissue carbon isotope ratio (δ13C) was used to determine the occurrence of crassulacean acid metabolism (CAM) and C3 photosynthesis in 1893 species, representing 57% of species and all 56 genera in the family. The frequency of δ13C values showed a strongly bimodal distribution: 1074 species (57%) had values more negative than −20‰ (mode = −26.7‰), typical of predominantly daytime carbon fixation via the C3 pathway, whereas 819 species (43%) possessed values less negative than −20‰ (mode = −13.3‰), indicative of predominantly nocturnal fixation of carbon via the CAM pathway. Amongst the six almost exclusively terrestrial subfamilies in Bromeliaceae, Brocchinioideae, Lindmanioideae and Navioideae consisted entirely of C3 species, with CAM species being restricted to Hechtioideae (all species of Hechtia tested), Pitcairnioideae (all species belonging to a xeric clade comprising Deuterocohnia, Dyckia and Encholirium) and Puyoideae (21% of Puya spp.). Of the other two subfamilies, in the overwhelmingly epiphytic (plus lithophytic) Tillandsioideae, 28% of species possessed CAM photosynthesis, all restricted to the derived genus Tillandsia and tending towards the more extreme epiphytic 'atmospheric' life-form. In Bromelioideae, with comparable numbers of terrestrial and epiphytic species, 90% of taxa showed CAM; included in these are the first records of CAM photosynthesis in Androlepis, Canistropsis, Deinacanthon, Disteganthus, Edmundoa, Eduandrea, Hohenbergiopsis, Lymania, Pseudananas, Ronnbergia and Ursulaea. With respect to elevational gradients, the greatest number of C3 bromeliad species were found at mid-elevations between 500 and 1500 m, whereas the frequency of CAM species declined monotonically with increasing elevation. However, in Puya, at least ten CAM species have been recorded at elevations > 3000 m, showing that CAM photosynthesis is not necessarily incompatible with low temperatures. This survey identifies five major origins of CAM photosynthesis at a higher taxonomic level in Bromeliaceae, but future phylogenetic work is likely to reveal a more fine-scale pattern of gains and losses of this trait, especially in ecologically diverse and widely distributed genera such as Tillandsia and Puya
Observations of molecular hydrogen (H2) mixing ratio and stable isotopic composition (deuterium content) at the Cabauw tall tower in the Netherlands
<p>This zip file contains the final corrected data that were used for the journal article "Observations of molecular hydrogen mixing ratio and stable isotopic composition at the Cabauw tall tower in the Netherlands" by Batenburg et al., Atmospheric Environment, 2016, doi:10.1016/j.atmosenv.2016.09.058<br> <br> Please cite the original AtmosEnv article when using these data.<br> The paper also contains more information about how these data were collected and calibrated, and on how the quality control flags were assigned.</p> <p>All samples were collected at the Cabauw tower, at the CESAR site (51.971° N, 4.927° E, http://www.cesar-observatory.nl/).<br> H2 and deltaD(H2) are calibrated using one to four laboratory reference air cylinders, depending on measurement period.<br> The H2 mixing ratio of the reference cylinders was determined by UHEI-IUP, MPI-BGC, or the IMAU isotope laboratory.<br> The deltaD(H2) of the reference cylinders is, sometimes indirectly, linked to the VSMOW scale by measurements of air mixtures containing H2 standards of known isotopic composition.<br> H2 scale: MPI2009, Jordan and Steinberg, AMT, 2011, doi:10.5194/amt-4-509-2011<br> deltaD(H2) units: permil deviation from VSMOW, Gonfiantini et al., IAEA-TECDOC-825, IAEA</p> <p>Times are UTC. </p> <p><br> The corresponding author can be reached through annekebatenburg@gmail.com for questions.</p>
DATASET: Isotope Ratios, Carbon and Nitrogen Concentrations, and Phytoplankton Composition Data from the ACE Expedition
<p>This dataset represents the averaged observations derived from the Antarctic Circumnavigation Expedition (ACE - 2016/2017) and has been utilized for the analyses presented in the publication: "A circum-Antarctic plankton isoscape: Carbon export potential across the summertime Southern Ocean". It encompasses a comprehensive suite of biogeochemical measurements, specifically the isotopic ratios (δ13C, δ15N) and concentrations of carbon and nitrogen in Suspended Particulate Matter (SPM). Additionally, it includes data from High-Performance Liquid Chromatography (HPLC) analyses (i.e., Total Chl-a and fractions of pico-, nano-, and micro-phytoplankton).</p><p>This dataset also contains the outputs of our calculations based on the two-endmember isotope mixing model (Fawcett et al., 2011), complemented by the Rayleigh model (Mariotti et al., 1981) to deduce the fraction of phytoplankton biomass originating from new nitrogen source (New Production).</p>
Nitrogen isotope ratios of nitrate, ammonium, and amino acids in sinking particles in the Northwestern North Pacific
<p>The database includes sample information and nitrogen isotope measurements of nitrate, ammonium, and amino acids in sinking particles in the Northwestern North Pacific. The sinking particles were collected in sediment traps moored at depths of 200, 500, and 4,810 m at station K2 (47°N, 160°E; water depth, ~5,200 m). The seawater was sampled with a plastic bucket for the surface and Niskin-X sampling bottles for water below the surface at stations K2 and KNOT (44°N, 155°E). The model package of a 1D nitrogen isotope model includes model source code written in Fortran 90, forcing, and initial condition at station K2.</p>
Determining sugar and molasses origin by non-exchangeable hydrogen stable isotope of ethanol and carbon isotope ratio mass spectrometry
<p>This study explores the differentiation of sugar and molasses produced from sugar beet and cane, which are susceptible to fraudulent labeling due to differing production costs. The research aimed to authenticate these products by botanical origin using novel analytical techniques. Utilizing ethanol isotopic measurement–isotope ratio mass spectrometry (IRMS) for non-exchangeable hydrogen stable isotopes alongside carbon stable isotopes analysis through elemental analyzer–IRMS, the study accurately identified the origin of various sugar and molasses samples, pinpointed mislabeled goods, and determined the source of products with previously unknown provenance. These methods were also effective in revealing sugar and molasses adulteration and quantifying the extent of such fraud. The combined isotope analyses demonstrated their potential as robust tools for combating misrepresentation and adulteration in the sugar industry.</p>
Stable isotope ratios data of NEREA Augmented Observatory
<p>Samples were collected at 1m depth or along the whole water column using Niskin bottles and plankton nets, transferred into bins or jars and transported to the laboratory, where the individual size fractions were isolated. For each size fraction, samples were frozen and freeze-dried individually. Carbon and nitrogen stable isotope values (‰) were determined at the Stable Isotope Facility at the University of california in Davis (USA).</p>
Data and code for "Large volume injection and assessment of reference standards for n-alkane δD and δ13C analysis via gas chromatography isotope ratio mass spectrometry"
<p>This file includes data and code related ot the publication, "<span>Large volume injection and assessment of reference standards for <em>n</em>-alkane δD and δ<sup>13</sup>C analysis via gas chromatography isotope ratio mass spectrometry" in Rapid Communications in Mass Spectrometry (in review). Included are datasets of <em>n</em>-alkane δD and δ<sup>13</sup>C measurements with a recently developed large-volume injeciton method. Measuremtns of reference standards and lake sediment samples from Eifel maar lakes of Germany are included. Additionally, code to implement the correction schemes and reporduce the figures and analysis described in the paper are included. </span></p>
Pulleniatina obliquiloculata stable oxygen isotope and Mg/Ca ratios record from IODP Core 363-U1483
<p><span>We carry out our work on a total of 202 sediment samples spanning the past ~400 kyr from IODP Core 363-U1483 (13.09°S, 121.80°E; water depth: 1733 m), which was recovered at the Timor Sea in the outflow area of the Indonesian Throughflow. In this study, we present Mg/Ca ratios and stable oxygen isotope from tests of planktonic foraminiferal Pulleniatina obliquiloculata, respectively.</span></p>
Globigerinoides ruber stable oxygen isotope and Mg/Ca ratios record from IODP Core 363-U1483
<p>We carry out our work on a total of 202 sediment samples spanning the past ~400 kyr from IODP Core 363-U1483 (13.09°S, 121.80°E; water depth: 1733 m), which is located close to the southern margin of the ITCZ's latitudinal displacement in the outflow area of the Indonesian Throughflow. In this study, we present Mg/Ca ratios and stable oxygen isotope from tests of planktonic foraminiferal Globigerinoides ruber, respectively.</p>
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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.