|Rowan collecting samples from the seafloor sediment|
The first proper science deployment is the CTD, and impressive contraption made up of many instruments to measure a range of oceanographic properties, including conductivity, temperature and depth, and 24 bottles to take water samples at various depths. The first couple of CTD deployments are at locations where data has been collected in previous year and therefore add data to ongoing studies of the Southern Ocean. The instrument first descends to its maximum deployment depth (approximately 1km at these initial locations) continuously recording data as it goes. As the CTD ascends the bottles are activated by an observing scientist on the ship collecting water at different depths for later analysis.
|The CTD equipment|
|Humpback whales circling the ship|
Leaving P2, and the whales behind, we continued towards South Georgia where we would be resupplying bases at Bird Island and King Edward Point. On the way we were able to deploy the box corer to sample the sediment on the South Georgia shelf, the reason I joined the cruise! The box corer is essentially a big box with a shovel that closes when it hits the seafloor, collecting around 30cm of surface sediment. We were able to deploy the box corer at two locations, in around 250m water depth, and recovered sediment from both locations, in spite of the box corer failing to fire a couple of times! Once the box corer was on deck, I subsamples the sediment with my supervisor, Vicky Perk, collecting four cores and as much of the top 1cm of sediment as possible. I am now processing the sediment so that can study the foraminifera (a single-celled organism that grows carbonate shells in a range of beautiful forms) in the sediment. Observations of which species live in the surface sediment, under current oceanographic conditions, will inform how I interpret fossil data from the Holocene cores that make up my PhD project.
Rowan is supervised at the BGS by Melanie Leng, at the University of Nottingham by Sev Kender, and at BAS by Vicky Peck and Claire Allen.