DNA metabarcoding of zooplankton biodiversity is used increasingly for monitoring global ocean ecosystems, requiring comparable data from different research laboratories and ocean regions. The MetaZo...

There is an increasing need for legislation worldwide to monitor and assess the ecological status of marine ecosystems, due to increasing pressures fr…

DNA metabarcoding of zooplankton biodiversity is used increasingly for monitoring global ocean ecosystems, requiring comparable data from different research laboratories and ocean regions. The MetaZo...

DNA metabarcoding of zooplankton biodiversity is used increasingly for monitoring global ocean ecosystems, requiring comparable data from different research laboratories and ocean regions. The MetaZo...

A zulip chat group for members of the geochronology research community, with an emphasis on sharing tips, techniques and procedures for high-precision geochronology as well as inter-laboratory and int...

An International Study of the Marine Biogeochemical Cycles of Trace Elements and Isotopes - Trace Element data available including an on-line Atlas eGEOTRACES

The increasing availability of vegetation-plot data results from decades of field surveys conducted by numerous observers. This highlights observer error not as a marginal issue but as a structural co...

arXiv abstract link

ABSTRACT Rationale Isotope ratio mass spectrometry (IRMS) and proton nuclear magnetic resonance (1H NMR) spectroscopy are independent techniques for determining the isotope ratio R(13C/12C) in organic compounds. However, the lack of suitable reference materials has limited intercalibration of results from these methods. Methods Three high-purity calcium formate isotopic reference materials were developed, each ideal for accurate isotope ratio measurements by both 1H NMR and isotope-ratio mass spectrometry (IRMS). For each material, R(13C/12C) was determined by 1H NMR, and the relative isotope abundance (δ 13CVPDB-LSVEC) by IRMS. The combined IRMS and NMR results were used to determine the R(13C/12C) value of Vienna Peedee belemnite (VPDB). Results The combined datasets yield a value for R(13C/12C) of 0.0111050 ± 0.0000047 (k = 2) for VPDB, which is 6.7‰ lower than the commonly cited value of 0.011180, but similar to other recent determinations. These three calcium formate reference materials exhibit high accuracy across both analytical methods and provide robust tools for instrument calibration, method validation, and inter-laboratory comparison in carbon stable isotope ratio analysis. Conclusions An accurate R(13C/12C) value for VPDB strengthens the link between relative (δ 13CVPDB-LSVEC) values from IRMS and R(13C/12C) isotope ratios from NMR and other techniques. These three calcium formate isotopic reference materials (USGS106, USGS107, and USGS108) are available from the US Geological Survey and provide reference materials for calibration, method validation, and inter-laboratory comparison in carbon isotope ratio analysis.