Diapycnal mixing across the photic zone of the NE Atlantic

Abstract. Variable physical conditions such as vertical turbulent exchange, internal wave, and mesoscale eddy action affect the availability of light nutrients for phytoplankton (unicellular algae) growth. It is hypothesized that changes in ocean temperature may density stratification, which hamper exchange. In order to quantify variations northeast Atlantic Ocean, we sampled a latitudinal transect along 17 ± 5∘ W between 30 63∘ N summer. A shipborne conductivity–temperature–depth (CTD) instrumented package was used with custom-made modification pump inlet minimize detrimental effects ship motions on its data. Thorpe-scale analysis establish turbulence values upper 500 m from three six profiles obtained short CTD yo-yo, 3 5 h after local sunrise. From south north, average decreased together stratification while weakly increased or remained constant. Vertical nutrient fluxes did not vary significantly latitude. This apparent lack correspondence mixing likely due waves breaking (increased can support more waves), acting potential feedback mechanism. As this mechanism mediates environment temperature, global surface warming large degree. We urge modellers test deduction it could imply future summer productivity stratified oligotrophic waters would experience little alterations input deeper waters.