Oceanography during TYDEMAN cruise DCM (DeepChlorMax) to the Equatorial Atlantic ...

• Main Authors: Veldhuis, Marcel J W, Fransz, H George, de Bruin, Taco F
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1996
• Subjects: Underway cruise track measurements; Absorption and beam attenuation; CTD/Rosette; Advanced spectral irradiance meter; Multiple opening/closing net; Vertical net; Secchi disk; Spectral radiometer; Trap; DCM; Tydeman; Joint Global Ocean Flux Study JGOFS; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.761718; https://doi.pangaea.de/10.1594/PANGAEA.761718

The cruise with RV Tydeman was devoted to study permanently stratified plankton systems in the (sub)tropical ocean, which are characterised by a deep chlorophyll peak between 80 and 150 m. To minimise lateral effects by horizontal transport of nutrients and organic matter from river outflow and upwelling regions, stations were selected in the middle of the North Atlantic Ocean between the continents of America and Africa. (5 - 35° N and 50 - 15° W). Here the vertical distributions of light and nutrients control the abundance and growth of autotrophic algae in the thermically stratified water column. This phytoplankton is numerically dominated by the prokaryotic picoplankters Synechococcus spp. and Prochlorococcus spp., which are smaller than 2 ?m. The productivity of the 100 to 150 m deep euphotic zone can be high, because a high heterotrophic/autotrophic biomass ratio induces a rapid regeneration of nutrients and inorganic carbon. Primary grazers are mainly micro-organisms such as heterotrophic ...