Wave-driven upwelling pump deployed south of the Canary Islands

As part of the Test-ArtUp field activities, a wave-driven deepwater pump was tested in the nutrient-poor subtropical Atlantic Ocean, ~140 nautical miles south of the Canary Islands from Nov 16 to 21. One day after the deployment of the pump by the Spanish RV Sarmiento de Gamboa, a 10-member Test Art-Up team conducted measurements from aboard the sailing vessel Pandora V.

As the ~2.5-ton bottom weight sank, the 200-meter pump hose uncoiled, pulling the end of the hose into the depths and filling the 1.9-meter-wide hose, whereupon the pump immediately began to operate. To assess the distribution and mixing of the pumped deep water in the vicinity of the pump, Uranine was injected as a dye and monitored by a CTD equipped with a Uranine sensor. To the team’s surprise, it seemed like there was little to no pumping activity at that time and later data revealed that the pump tube had lost its bottom weight shortly after deployment. However, in the first 3 hours, the flowmeter at the outlet detected pumping rates, higher than originally estimated based on the wave properties.

More information about this deployment can be found on the GEOMAR homepage: https://www.geomar.de/en/news/article/greening-the-ocean-to-combat-climate-change

GEOMAR divers follow the dispersion of the dye uranin. Above the drift buoy, below the rectangular upper outlet of the pump hose (Photo: Michael Sswat, GEOMAR).