If you have ever played the game MONOPOLY you are familiar with this: Go back to start …, do not pass go…, do not collect $$. Every so often it also happens in real live that you have to start all over again. It’s always painful, but sometimes it’s better to do it in time than to carry on with something that is doomed to fail.

Underwater view of compressed mesocosm bag. Photo: Michael Sswat, GEOMAR

This is the situation we found ourselves in when watching our mesocosms lose more and more of its precious contents. It wasn’t much, barely a glass of water per minute. But over time this caused a considerable drain from our mesocosm bags. Due to the large salinity difference between the enclosed and the surrounding water, hydrostatic pressure was building up at the bottom of the bags. It seems the sealing at the flanges connecting the sediment traps couldn’t quite endure this pressure. A slow but continues drain of water eventually caused the top sections of the mesocosm bags to get compressed. This made it almost impossible to run the water samplers, let alone to take net tows or clean the mesocosm walls. As long as the density difference between inside and outside the bags remained as huge as it was during the past eight days, the situation could only get worse.

Under these circumstances we took the painful decision to go back to start …. We did not pass go and did not collect … no, not dollars, data. In fact, most of the data we had collected over the past two weeks became worthless from one moment to the next. That was indeed very painful. In practice our decision meant to open the mesocosms at top and bottom, let the heavy water fall out and be replaced by lighter fjord water. It sounds easy and straightforward, but in reality means days of hard work. When our divers unlocked the bottom flanges today, they took them back to shore to check for small leaks and apply additional sealing. “Bombenfest”, as Jan put it. Let’s hope he’s right.

Now we are hoping that the phytoplankton will take it easy. It takes us at least 4 days of intense work to get back to start and be ready for a new trial – and we don’t want to miss the bloom. All the sudden a dark and grey day is a good day. Fingers crossed.