Oceanic Rossby waves acting as a "hay rake" for ecosystem floating by-products

Yves Dandonneau (1) , Andres Vega (2) , Hubert Loisel (3) , Yves Du Penhoat (2) , Christophe E. Menkès (1)

1 LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques
2 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
3 LOA - Laboratoire d’Optique Atmosphérique - UMR 8518

Recent satellite observations of Rossby waves and chlorophyll anomalies propagating in subtropical gyres have suggested that wave-induced upwelling could stimulate photosynthesis. Instead, we show that chlorophyll maxima are located in abnormally warm water, in Rossby wave-induced convergences. This excludes inputs of nutrients from deeper water. We argue that the sea color anomalies are not caused by chlorophyll but by floating particles evolved from the ecosystem, and accumulated by Rossby waves, acting as "marine hay rakes", in convergence zones. Such processes may be determinant for the distribution of living organisms in oligotrophic areas.

Mots clés: convergence; chlorophyll; floating particles; radiative transfer; teledetection

Domaines: Océan, Atmosphère; Géophysique [physics.geo-ph]

Yves Dandonneau, Andres Vega, Hubert Loisel, Yves Du Penhoat, Christophe E. Menkès. Oceanic Rossby waves acting as a "hay rake" for ecosystem floating by-products. Science, 2003, 302 (5650), pp.1548-1551. ⟨10.1126/science.1090729⟩. ⟨hal-00155085⟩