On 25th November 2018 RRS Discovery sailed on the first of CUSTARD’s three planned research trips, DY096. Leaving from Punta Arenas in Chile, and passing out into the southeast Pacific via Magellan Strait, the target was the National Science Foundation (NSF) Ocean Observatories Initiative (OOI) mooring site at 89W 55S. CUSTARD aims to study the factors affecting the biological uptake and storage throughout the year in a region for which few observations exist, resulting in a major uncertainty on the carbon cycle in the Southern Ocean, a key conduit of CO2 from the atmosphere into the ocean.

The Southern Ocean is a harsh place to be in winter. The OOI mooring has recorded waves over 20m in height. Hence, the main objective on DY096 was to deploy equipment that could stay out all year when no-one would want to be there in a ship. Through a collaboration with the NSF and OOI, a team from Woods Hole Oceanographic Institution (WHOI) came along both to deploy a mooring at the site (now equipped with novel sensors designed at the National Oceanographic Centre (NOC) and to recover existing moorings. Additionally, two gliders (Pancake and Churchill) were deployed, equipped with sensors to measure aggregates of organic carbon as it sinks through the water. Although the weather was a little challenging, the trip was a success and the CUSTARD team have already had the pleasure of watching the Southern Ocean phytoplankton bloom this southern spring, stripping the surface waters of  nutrient and despatching carbon to depth as dead cells, all from the comfort of their warm offices.

At the end of 2019, two more cruises to the site are planned: to do more detailed analysis of the local ecosystem and biogeochemistry (DY111) and to recover the equipment after its tough year in the Southern Ocean (DY112).

Adrian Martin, Principal Investigator.

Image credit: E. Haigh.