Blog: “It’s not funny!” – Elise Droste

22/12/2018

The Southern Ocean was obviously not going to let us pass with only 2 metre high waves. The smoothness of the ocean made it difficult to imagine that it would ever turn into a wilder version of itself, but when it did, it was believable. We were all urged to double check that our equipment was well secured in the labs so that the 5 metre high waves wouldn’t knock them over. When we were presented with the prospect of a newly developed storm meeting us on our cruise track along with 6 metre high waves, the room filled with nervous giggles. But when the captain at that point turned around in his seat and urged, “It’s not funny”, the giggles quickly died. It was deemed safer to change our track in order to avoid the storm hitting us right on.

This meant that we would have to make up for some time, so the CTDs that we’re deploying until we get to the zero meridian will only go to 2000 metre depth instead of to the bottom of the ocean. Among other research interests, the CTD deployments are crucial for the biogeochemical (BGC) floats that we’re deploying, the sensors of which will need calibration using the water sample analyses.

Stormy conditions during the first SOCCOM float deployment of the cruise.

This morning, at 01:30 AM, the first BGC SOCCOM float was deployed (a Navis SeaBird BGC float with an oxygen sensor, nitrate sensor, Ocean Color Radiometer, fluorescence and  backscatter, and a pH sensor mounted on it). Together with a watchman, Paul had to deploy it from the working deck that was otherwise prohibited due to safety concerns. The float was soon sinking to its activation depth, at which it will wake itself up and come to the surface to make contact. By the time it makes its first call from the ocean to the server, we’re already long gone from its location. Perhaps on Monday (after the weekend), we will receive a confirmation of the float’s life as a Christmas gift. We didn’t have time to think about it right after the deployment, as we had to take over 80 water samples for calibration purposes.

At CTD stations where a biogeochemical Argo float is deployed, we take oxygen, dissolved inorganic carbon/total alkalinity, pH/alkalinity, nutrients, HPLC, POC, and salinity samples. Most of these are used to calibrate the float’s sensors. In total, we took over 80 water samples for one biogeochemical float deployment station!

Elise Droste is based at the University of East Anglia and is deploying the Argo floats from the RV Polarstern for the winter 2018/19, as part of the team working on the PICCOLO project in RoSES. She’s also taking dissolved inorganic carbon (DIC) and total alkalinity samples to use in her PhD project about the carbonate chemistry of the seasonally ice-covered regions in the Southern Ocean.