The LSCE (CEA-CNRS-UVSQ-UPSaclay) took part in exercises to compare boron isotope measurements to the best in the world. The aim is to share common references for research into ocean acidification and its impact on calcifying marine organisms.
In order to study the acidification of the ocean caused by the increase in anthropogenic CO2 emissions, the LSCE has developed geochemical tools using the measurement of boron and its isotopes (11B, 10B) in carbonates of biological and marine origin. These tracers were initially used to reconstruct changes in the acidity (pH) and chemistry of ocean carbonates.
They also characterise the ability of organisms such as corals to form their calcareous skeleton and therefore their resilience to changes in their habitat. Researchers are measuring the isotopic content of boron-11 (ratio 11B/10B) and the boron and calcium (B/Ca) content in the aragonite that forms the skeleton of a coral colony. These measurements enable them to determine the physical and chemical properties of the internal calcification fluid that regulate coral growth and development.
To achieve this, it is necessary to measure the isotopic composition of boron in corals and seawater to within a few 0.1 ‰ and, to do this, to have perfectly characterised carbonates or reference solutions.
The LSCE recently took part in two inter-laboratory comparison exercises. The researchers very accurately determined the 11B and 10B isotope content of two international standard carbonates (coral and bivalve), regularly used in laboratories, and also characterised new standard solutions (coral and foraminifera) from the National Institute of Standards and Technology, which will soon be available to the scientific community.
This work demonstrates the quality of the measurements carried out by LSCE experts on boron isotopes in natural archives using MC-ICPMS Neptune plasma source mass spectrometry.
Since then, NIST standards featuring these inter-lab comparison exercises have been available on the market :
https://www-s.nist.gov/srmors/quickSearch.cfm?srm=8301
References :
Gutjahr M., Bordier L., Douville E., Farmer J., Foster G.L., Hathorne E.C., Hönisch B., Lemarchand D., Louvat P., McCulloch M., Noireaux J., Pallavicini N., Rae J.W., Rodushkin I., Roux P., Stewart J.A., Thil F. and You C.‐F. (2020) Sub‐Permil Interlaboratory Consistency for Solution‐Based Boron Isotope Analyses on Marine Carbonates. Geostandards and Geoanalytical Research. doi: 10.1111/ggr.12364
Stewart J.A., Christopher S.J., Kucklick J.R., Bordier L., Chalk T.B., Dapoigny A., Douville E., Foster G.L., Gray W.R., Greenop R., Gutjahr M., Hemsing F., Henehan M.J., Holdship P., Hsieh Y.‐T., Kolevica A., Lin, Y.‐P. Mawbey E.M., Rae J.W., Robinson L.F., Shuttleworth R., You C.‐F., Zhang S. and Day R.D. (2020) NIST RM 8301 Boron Isotopes in Marine Carbonate (Simulated Coral and Foraminifera Solutions): Inter‐laboratory δ11B and Trace Element Ratio Value Assignment. Geostandards and Geoanalytical Research. doi: 10.1111/ggr.12363
Contact : Éric Douville (LSCE)
