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#FridayScience 4

Tous on Fridays, we popularize one or more studies on microplastics in the Mediterranean.

The North Mediterranean Current: a major role in the distribution of microplastics?


What is the North Mediterranean Current?

Passing along the Italian, French and Spanish coasts, the North Mediterranean Current (NMC) dominates the Western Mediterranean basin. The current flows cyclically from the Gulf of Genoa (Italy) to the southern Gulf of Valencia (Spain).

Carte Courant nord mediterraneen.png

Cyclonic circulation of the North Mediterranean Current (CNM)

Circulating along highly populated coasts for millennia and in front of the mouths of large rivers , scientists have wondered about the potential role of this current in the distribution of micro-plastics. Indeed, research shows heterogeneity in the distribution of micro-plastics with areas much more concentrated than others (see #FridayScience2 ). The Balearic archipelago, for example, appears to be an area of high accumulation of plastics , which may seem quite paradoxical given its geographical position. 

carte population _reduite.jpg

Traffic along large urbanizations

carte bassin versant.png

A circulation along the mouths of rivers with very large catchment areas

A proven role in the distribution of micro-plastics?

Several studies highlight the role of CNM in explaining the distribution of microplastics. Indeed, it is a strong hypothesis to explain the high abundances of micro-plastics in the Catalan and Balearic Seas due to:

  • the proximity of the CNM to the coast can lead to a higher rate of dispersion of microplastics closer to the shores

  • the accumulation of micro-plastics along its trajectory as it passes through the Ligurian Sea and the Gulf of Lion

Studies estimate that the CNM could transport up to 1 trillion plastic micro-particles , or a weight of 86 tons [2] [5]!

A problem at the heart of the SEA Plastics 2020 expedition

The SEA Plastics 2020 expedition has the ambition, in the same direction of existing studies, to sample from Monaco to Alicante passing through both the Balearic Islands and the Catalan coast, in order to strengthen the hypothesis of the role of the CNM in the distribution of micro-plastics and to detect other possible areas of accumulation. 

Bibliography :  

[1] Arnau, P., Liquete, C., Canals, M., 2004. River mouth plume events and their dispersal in the Northwestern Mediterranean Sea. Oceanography 17 (3), 22–31.


[2] Schmidt, N., Thibault, D., Galgani, F., Paluselli, A., Sempéré, R., 2018. Occurrence of microplastics in surface waters of the Gulf of Lion (NW Mediterranean Sea). Prog. Oceanogr. 163, 214–220. (Elsevier).


[3] El-Geziry, TM, Bryden, IG, 2010. The circulation pattern in the Mediterranean Sea: issues for modeling consideration. J. Opera. Oceanogr. 3, 39–46.


[4] Poulain, PM, Menna, M., & Mauri, E. (2012). Surface geostrophic circulation of the Mediterranean Sea derived from drifter and satellite altimeter data. Journal of Physical Oceanography, 42(6), 973-990.


[5] Millot, C., 1999. Circulation in the western Mediterranean Sea. J. Mar. Syst. 20, 423–442.

Synthesis and writing: Aitor Fernandez, Clea Abelló

GUI:  Benjamin Pannetier


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