After our series of monthly cruises (May-July), the big moment was here, and the autonomous observatories that had been deployed in late September last year should be retrieved. In seasonally ice-covered Arctic glacial fjords, it is impossible to have such installations with a surface unit that continuously transmits data – but we have to stay at least around 10 m below the water surface with the floating unit. Hence, the moment of retrieval is really thrilling (and a little bit magic) – as you will know only then whether you got your precious instruments (and data!) back or not. During almost 15 years of continuous mooring deployments in Svalbard (see also: :….), the retrievals were always successful, and no equipment or data were lost. Generously, the scientists responsible for the zooplankton course at UNIS had agreed on retrieving and re-deploying our moorings during the annual cruise in late August. But unfortunately, things went not as smoothly as anticipated. The first mooring that should be retrieved was the one behind Akselsøya that was meant to measure the water masses entering the fjord from the adjacent shelf areas. Although communication with the releaser unit was still possible, the equipment from this mooring seem to have vanished, and never surfaced. That was a big disappointment and bad start for the cruise. Probably, this area was exposed to too strong currents to assure a safe deployment?
Luckily, retrieval of the other two mooring (in the innermost part of van Mijenfjorden and Kongsfjorden) went really smoothly, and all sensors seem to have worked excellent during the past 12 months. Even the autonomous water samplers that were programmed to collect samples for phytoplankton taxonomy, nutrients and carbonate chemistry at numerous occasions throughout the year (with an up to weekly resolution during the spring months) had worked as planned – which is not self-evident under harsh Arctic conditions, and sometimes sub-zero water temperatures in winter. We will now spend the coming months on analyzing the data that give us a unique insight into algal bloom development in an exceptionally warm year that probably should be considered a future scenario for both our sampling locations. A great thanks to everyone who was involved in the mooring operations – in particular Daniel and Finlo!