The team worked incredibly hard over the past two weeks, but Johan finally found some time to explain what some team members have been busy with on the way south to Antarctica
Soon after the Agulhas left Cape Town preparations began for all sections of team TraceEx. Other than preparing for trace metal sampling and launching of McLane pumps there was also being prepared for underway sampling. Underway sampling is essentially the sampling ocean surface water using the ship’s underway water supply which is continuously pumping into two of the labs, except for when were in ice and it’s too cold, which happened, on-board the ship where a tap can be opened and sampled from. Three of our team members (Johan, Ian and Jodi) occupied one of these labs and basically became their home for the next few days southbound on the first leg of the Winter cruise.
During the Southbound leg of the cruise Johan, Ian and Jodi sampling for Phytoplankton pigments, POC and occasionally macronutrients. POC was subsampled and filtered while pigments were directly filtered from the tap using an in-pine filter holder and both filters kept and stored in freezers. Phytoplankton pigments will be used to chemically determine the phytoplankton community structure in surface waters along the ships transect, part of Johan’s project, and the POC the total biomass of the phytoplankton. These were sampled every 4 hours by the underway “stowaways” to fit into the underway sampling of the other teams on-board. This was to ensure that most data collected on the cruise can be used in a way to easily request information from other teams that matches the same data points. This way all teams benefit the most from the cruise.
After a tuff few days of days of strange sleep patterns, and fighting of the ever-looming sea sickness caused by the midwinter Indian Southern Ocean, they successfully sampled around 5 pigments and 3 POC samples per day when we reached the pancake ice. Pigments were more due to the interest in what happens to the phytoplankton community across the oceanic fronts. It could be seen on the underway sampling data how the ocean temperature change from a “warm” 14degC to a freezing -3degC at some point within the ice. When the ice was reached it was the end of underway sampling with some relief, not knowing what lie ahead in term of ice station sampling and never-ending filtering water from CTD stations….