Helium isotopes help to constrain high-resolution model dynamics in the Mediterranean Sea

Science Highlights

11 January 2016

The terrigenic helium isotope distribution was simulated for the first time in the whole Mediterranean Sea, using a high-resolution model (NEMO-MED12) at one-twelfth of a degree horizontal resolution (6–8 km).

Together with providing valuable constraints on the crustal and mantle helium fluxes, the simulations and their comparisons with observations provide a new technique for improving the dynamical regional model. This is clearly illustrated by the confirmation of the shortcomings of the model dynamics in representing the deep ventilation of the Ionian sub-basin…

16 Ayache
Figure: Total δ 3He (sum of terrigenic, tritiugenic and atmospheric helium) model–data comparison along the Meteor M5 (September 1987) section. (a) Colour-filled contours indicate simulated δ 3He (%), whereas colour-filled dots represent in situ observations. (b) and (c): comparison of average vertical profiles for the Levantine and Ionian sub-basins, respectively; model results are in blue; red indicates in situ data. Click here to view the figure larger.

Reference:

Ayache, M., Dutay, J.-C., Jean-Baptiste, P., & Fourré, E. (2015). Simulation of the mantle and crustal helium isotope signature in the Mediterranean Sea using a high-resolution regional circulation model. /Ocean Science/, /11/(6), 965–978. doi:10.5194/os-11-965-2015

Latest highlights

Mercury content and isotopes in bird’s guano: a window to reconstruct past climates

By analysing peat cores, Chuxian Li and her colleagues have shown how populations of nesting seabirds have fluctuated on a sub-Antarctic Island over the last 8,000 years.

Contraction of North Atlantic Deep Water during glacial times: a paradigm called into question

Blaser and co-authors propose a new distribution of deep-water masses in the Atlantic Ocean during the Last Glacial Maximum and the Heinrich Stadial..

Authigenic radiogenic neodymium isotope composition traces millennial-scale overturning circulation variability in the Arabian Sea

The neodymium isotopic signature of the sediment authigenic fraction is, a priori, a valuable proxy for reconstructing deep-water mass trajectories…

Magmatic activity at the Carlsberg Ridge in the Indian Ocean triggered by glacial sea-level variation

De and colleagues provide a high-resolution record of magmatic input and associated hydrothermal activity over the past 49 kyr from a core recovered from a magmatic segment of the slow-spreading Carlsberg Ridge in the Indian Ocean.

Rechercher