Let’s simulate deep-water upwelling in our mesocosms. Easy to say – but how do you collect 80,000 litres of water from 400 m water depth off-shore and deliver it to the KOSMOS playground?

Pumping it with a long hose lowered to depth into a huge bag on-board R/V POSEIDON and ship it to shore? Considering POSEIDON’s payload of 24 tons, this does not sound like such a good idea. But if the bag stays in the water, maybe POSEIDON could tug it to shore? That might work.

Pumping 80,000 litres from 400 metres depth in reasonable time needs a strong underwater pump and a heavy-duty hose with a large diameter. In principle this seems possible, but the hose drum for this would have to be big. Well then, how about lowering a large bag to depth, filling it down there and sending it back to the surface? Sounds crazy, but why not give it a try?

This was the state of discussion last spring. What followed was a year of intense work by Jan Czerny, Mario Deckelnick, Ralf Doose, Ralf Schwarz and Uwe Lentz , designing and constructing a system no one has ever built before. Needless to say, the first operation of this large-volume deep-water collector under realistic conditions yesterday was anticipated with great excitement and a good deal of tension.

The deployment of the deep-water collector from R/V POSEIDON and down to 400 metres, its filling at depth, its rising back to the surface after remotely releasing the weight, and its tugging for four nautical miles to shore by POSEIDON all went smoothly and as planned. In fact, it couldn’t have gone any better. It was impressive to see how an out of the ordinary idea became reality. Now the collector is moored next to our mesocosms and ready to supply its waters to simulate a deep-water upwelling event under controlled conditions.

After the setbacks suffered during the last week, yesterday’s success made a big difference for the KOSMOS team. At the end of the day we were all excited about this break-through and are now confident about applying this technique in a repeat experiment here off Gran Canaria and in other future KOSMOS campaigns.

Thank you to everyone involved in this operation: the captain and crew of R/V POSEIDON, the GEOMAR diving team, and above all to the designers and constructors of this ingenious, one of a kind deep-ocean large-volume collector. CONGRATULATIONS to Jan, Mario, and the rest of the team at GEOMAR’s technology and logistics centre for a great success.