Rare Earth Elements and neodymium isotopes as tracers in the Mediterranean Sea

Garcia-Solsona and co-workers (2020, see reference below) analysed 9 seawater stations around the central Mediterranean Sea (MS) to clarify the relative importance of external sources, vertical (biogeochemical) processes and lateral water mass transport in controlling Rare Earth Elements (REE) and neodymium isotopic composition (εNd) distributions.

Their results clearly identify the influence of continental input from the western Italian coast to the Tyrrhenian surface waters, marked by a negative correlation of surface light REE enrichment with offshore distance.

Contrastingly, a reasonable conservative behaviour of heavy REE and εNd is observed in the Central MS. This contrast induces a decoupling of [Nd] and εNd in all water masses of the central MS below the thermocline.  

The conservativity of heavy REE and εNd as water mass mixing tracers was successfully established using an Optimum Multi-Parameter Analysis (OMPA) and confirming that the distributions of heavy REE and εNd signals are determined by mixing of the water masses present in the region: Modified Atlantic Water (MAW), Levantine Intermediate Water (LIW), Eastern Mediterranean Deep Water (EMDW) and Western Mediterranean Deep Water (WMDW). From their results, authors further suggest that εNd helps traditional oceanographic tracers in better defining the intrusion of EMDW through the Strait of Sicily to the western Mediterranean basin.

HiRes
Figures: The bottom figure is a map of the Central Mediterranean Sea with sampled stations in coloured dots. The dashed green line indicates the NW-SE section used to display the eNd values represented in the figure above. Changes in eNd values may be ascribed to the presence of different water masses; for example, a tongue of radiogenic LIW is clearly delineated from its eastern origin to the western basin.

Reference:

Garcia-Solsona, E., Pena, L. D., Paredes, E., Pérez-Asensio, J. N., Quirós-Collazos, L., Lirer, F., & Cacho, I. (2020). Rare earth elements and Nd isotopes as tracers of modern ocean circulation in the central Mediterranean Sea. Progress in Oceanography, 185, 102340. DOI: https://doi.org/10.1016/J.POCEAN.2020.102340

Latest highlights

Science Highlights

Dissolved iron and manganese fates reveal processes along the hydrothermal TAG plume

González-Santana and co-workers performed high-spatial resolution analyses of dissolved iron and manganese samples collected at the Mid Atlantic Ridge

20.10.2020

Science Highlights

The power of combining geochemical tracer data with direct current measurements

Learn about new discoveries done combining seawater Rare Earth Elements concentrations and direct physical oceanographic observations

14.10.2020

Science Highlights

Loss of old Arctic sea ice increases methylmercury concentrations

Researchers from the SCRIPPS, the Stockholm Natural Museum and the Mediterranean Institute of Oceanography show the importance of sea ice composition on methylmercury budgets

02.09.2020

Science Highlights

Estimating Atmospheric Trace Element Deposition Over the Global Ocean

A recently developed method based on the natural radionuclide beryllium-7 has provided a means to estimate the bulk atmospheric trace element deposition velocity

Rechercher