Carol Arrowsmith is a chief technician in the stable isotope facility at the BGS. She recently took part in an expedition to the Southern Ocean as part of  ORCHESTRA (Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports), a NERC funded programme with partners at the British Antarctic Survey (lead), the National Oceanography Centre, Plymouth Marine Laboratory, and many more including BGS. Here she updates us as she nears the end of her expedition on the RRS James Clark Ross… 16 May 2019.

We were at sea for around 8 weeks on the RRS James Clark Ross, undertaking the ANDREXII transect. We set off from the Punta Arenas, Chile, calling in at the Falklands before crossing the Drake Passage to the tip of the Antarctic Peninsula at 60oS, and then out along over 3000 miles to the Indian Ocean at 30oE. 

Along this route we collected samples at 96 separate locations (stations), resulting in >1800 water samples for oxygen and carbon isotope analysis with help from my buddy, Margot Debyser from Edinburgh University and Ash Smith, the BAS Laboratory Manager. The samples will arrive back in the UK for analysis at the BGS in the summer for isotope analysis and will tell us about how much carbon the ocean has absorbed and how much fresh water has been added from melting of the ice caps. We also collected around 350 for radiocarbon C14 analysis which will be sent to the Woods Hole Institute, USA where we’ll be able to shed light on the age of the water. These samples form part of the 5 year ORCHESTRA research programme to try to understand the structure of the Southern Ocean and, more importantly, what changes are taking place within the ocean due to human impact.

After we finished the last sampling in the Indian Ocean our ship steamed back to the South Orkney Islands and Signy. There were plenty of seals (fur, leopard and crabeater) dotted about the ice, most of them were used to seeing ships and didn’t bother to move when they saw us coming! In particular, we got to see the British Antarctic Survey base, which is now evacuated for winter, and moved some cargo around the holds in readiness for the journey home. We then sailed down to the ice sheet forming around the Antarctic Peninsula, where we held the end of cruise dinner: a BBQ on the ship’s deck while it was snowing! 

The ship docked at Mare Harbour on the Falkland Islands, where we spent the day demobilizing, taking inventories of samples, packing up the equipment, and generally clearing up. We also had a flying visit to Volunteer Point to see King and Gentoo Penguins. The RRS James Clark Ross then left the Falklands for the first of 2 trips to Rothera Station to pick up scientists, crew, contractors and equipment to take them home.
Overall, it’s been a successful research cruise but I am glad to be back on land! I would like to thank PSO Andrew Meijers at BAS for his leadership and management. Also many thanks to the dedicated crew on board, engineers, deck crew and stewards who all played their part.