Isotope geochem. Is in the midst of a remarkable period of innovation and discovery; the last decade (or so) has seen the emergence of 'non-traditional' stable isotopes of metals (i.e., variations in isotopic compns. Of Mg, Fe, Cu, etc.), a great expansion of mass-independent isotope geochem., the invention of clumped isotope geochem., and new. Stable isotope analysis for carbon and oxygen of the marble sculptures from the mausoleum of Halicarnassus including the horse, denoted by H (see inset), superimposed on the data for Classical marble quarries. The ellipses represent 90% confidence limits for the samples from the named quarries. Center for Stable Isotopes The University of New Mexico Center for Stable Isotopes is a non-profit research focused laboratory and analytical facility founded in 2014. The mission of UNM-CSI is to support world-class stable isotope research by scientists and students across disciplines from Earth and Planetary Sciences, Biology, Anthropology. Stable Isotopes Supplier Serving the medical, scientific research and nuclear communities with Stable Isotopes for over 30 years, Trace Sciences International has been the leader in the sale and distribution of Isotopes. Unlike any other, we have the largest inventory in the world. Stable Isotopes are isotopic compounds that will not readily degrade. View detailed information on all of our available Stable Isotopes by clicking on the product name. Indicates a highly recommended product based on customer preference.
Stable isotope analysis can be used in ecological studies to trace chemical movement through the environment. A common application is to use the isotopic composition of a mixture to determine the proportions of various sources in the mixture, using mathematical mixing models. Examples include quantifying the importance of various pollutant sources to contaminated water, or the importance of various prey species in a predator’s diet.
The links below provide information and download files for three stable isotope analysis tools: IsoError, IsoConc, and IsoSource.
- IsoError
IsoError: Confidence interval calculation for source partitioning using stable isotopes
ISOERROR1_04 is a Microsoft Excel 2000™ spreadsheet that calculates estimates and confidence intervals of source proportional contributions to a mixture, using stable isotope analyses.
Examples include the quantifying proportions of:
- different pollution sources to contaminated air or water bodies
- food sources in an animal’s diet
- C3 vs. C4 plant inputs to soil organic carbon, etc.
Linear mixing models are used to partition two sources with a single isotopic signature (e.g., δ13C) or three sources with a second isotopic signature (e.g., δ15N).
The user supplies the mean, standard deviation, and number of samples from each of the source and mixture populations for each isotopic signature. For dual isotope studies, the correlations of the two isotopes within each population can also be specified, but are not required. The spreadsheet calculates the estimate proportion for each source (0-1), standard errors for these estimates, and approximate 95% confidence intervals. Confidence intervals are truncated at 0 and 1.
Download isoerror1_04.xls [Excel 2000 spreadsheet](76 K)
- IsoConc
IsoConc: Concentration-dependent stable isotope mixing model
ISOCONC1_01.xls is a Microsoft Excel 2000™ spreadsheet which performs calculations for the concentration-weighted stable isotope mixing model. This dual-isotope model takes into account isotopic element concentration differences among the sources in determining the proportional contributions of sources to a mixture. The user supplies the isotopic signatures for each source and the mixture, as well as the isotopic element concentrations for each source. Separate estimates are made of the contributions of each source for total mass and each isotopic element.
Download Isoconc1_01.xls [Excel 2000 spreadsheet](185 K)
- IsoSource
IsoSource: stable isotope mixing model for partitioning an excess number of sources
IsoSource version 1.3 is a Microsoft Visual Basic™ software package which calculates ranges of source proportional contributions to a mixture based on stable isotope analyses when the number of sources is too large to permit a unique solution (> number of isotope systems + 1). [It may also be used for other non-isotopic tracers such as concentrations of trace chemicals.]
Best wma player for mac. Examples include partitioning of:
- pollutant sources in a waste stream
- food sources in an animal’s diet,
- water sources for plant uptake,
- carbon sources in soil organic matter, and many others.
This software provides the distribution of source proportions which are consistent with isotopic mass balance.
The user supplies the isotopic signatures (e.g., atom %, isotopic ratios, or δ values) for the mixture and each of the sources. The user also supplies the source increment (e.g., entering a value of 1% specifies examination of all possible combinations of sources contributions from 0-100% in increments of 1%), and the mass balance tolerance (e.g., entering a value of 0.1‰ specifies that all source combinations that result in predicted mixture signatures within 0.1‰ of the observed signature are considered as feasible solutions).
IsoSource provides output files which list each feasible solution, descriptive statistics about the distribution of these solutions (number of solutions, mean, standard deviation, minimum, maximum, 1%ile, median, and 99%ile for each source), and histograms of these distributions. Output files can be viewed on-screen, printed, or read into other applications such as Microsoft Excel™ for further viewing or manipulation.
Additional non-isotopic constraints can be incorporated by extracting appropriate subsets of solutions from the IsoSource output. Additional information on this post-processing is given in the 'Additional constraints.pdf' link shown at the bottom of the page.'
NOTE - Each of the individual solutions represents a combination of source proportions which satisfies isotopic mass balance in the mixing model. Descriptive statistics are provided simply as a way to characterize this entire distribution of feasible solutions. To avoid misrepresenting the results, users of this procedure should report the distribution of feasible solutions rather than focusing on a single value such as the mean.
Download IsoSource Version 1.3.1(9 MB)[IsoSource software in a zip file - Unzip the file and run Setup.exe]Additional constraints: procedures for post-processing IsoSource results.
NOTE – Users running Windows 10 have experienced difficulties in locating the data and output files to read into other applications (e.g., Excel) for further analyses, although they still can be accessed for “View” and “Graph” functions in IsoSource. This seems to be an issue with read/write permissions in ‘C:/Program Files (x86)/IsoSource’, which is the default directory in which IsoSource is installed and the default directory for writing IsoSource data and output files. This problem can be circumvented in one of two ways: (1) When specifying the location where data and output files will be saved, navigate to a different directory instead of the default ‘C:/Program Files (x86)/IsoSource/data’ and ‘C:/Program Files (x86)/IsoSource/output’, respectively. (2) When installing IsoSource, choose a different location for installation than the default ‘C:/Program Files (x86)/IsoSource’ directory. Then when saving data and output files, the defaults will be the /data and /output subdirectories in the installation directory.
Further Information
Publications: Publications describing these methods and related applications
Contact: For further information on any of these models contact J. Renée Brooks at brooks.reneej@epa.gov
Stable Isotope Facility
Earth & Environmental Sciences Department
The Stable Isotope Facility performs world-class stable isotope and elemental analyses that support research in climate change, geology, oceanography, and paleontology. It is a shared analytical laboratory within the Earth and Environmental Sciences Department. Professors Kacey Lohmann, Julie Cole, and Sierra Petersen operate three independent research groups within this newly renovated space. We are also here to support your research.
These page pertain to the analytical facility. For outside links to ongoing research topics, group members and news:
SCIPP Lab (Stable and Clumped Isotopes for Paleoclimate and Paleoceanography)
PI: Sierra Petersen
Stable Isotope Analysis Definition
List Of Stable Isotopes
PACE Lab (Paleoclimate and Common Era)
PI: Julia Cole
Stable Isotope Diet
Lohmann Stable Isotope Lab
PI: Kacey Lohmann