RRS Discovery Cruise D340a::Reykjavik to Dunstaffnage via Rockall and the Wyville Thomson Ridge 10 June to 25 June 2009

• Main Author: Sherwin, Toby
• Format: Book
• Language: English
• Published: Scottish Association for Marine Science 2009
• Subjects: Rockall Trough; Wyville Thomson Ridge; Wyville-Thomson Ridge; Iceland
• Online Access: https://pure.uhi.ac.uk/portal/en/publications/rrs-discovery-cruise-d340a(0283deb1-9f6c-4bd9-9237-ab046240ca33).html; https://pureadmin.uhi.ac.uk/ws/files/17628122/268_d340a.pdf; https://www.bodc.ac.uk/resources/inventories/cruise_inventory/reports/d340a.pdf

This report describes the events and activities that occurred during D340, a joint SAMS / NOCS cruise on the NERC RRS Discovery that took place in the summer of 2009. The principle objective of the cruise was to undertake the sampling of the Extended Ellett Line, an annual section of CTD and bio-chemical monitoring stations that runs from Iceland to Rockall and on to Ardnamurchan Point in Scotland. The Ellett line is funded by NERC under Oceans2025 (http://www.oceans2025.org/). The principle activities were: 1. Undertake annual routine CTD + nutrients section along the Ellett line (see sketch) from Iceland to Scotland (OC2025, Theme10) 2. Recover 4 sediment trap moorings in the Iceland Basin (see box, OC2025, Theme 3) 3. Turn round ADCP mooring on the Wyville Thomson Ridge and undertake supporting CTD observations (OC2025, Theme 10) Additional measurements were: 1. Boron in the upper water column 2. Iron and other trace metals in the surface and water column 3. Low volume atmospheric sampling for trace metals 4. DMS, DMSP lyase activity 5. FRRf, proteins, flow cytometry and chlorophyll sampling 6. Phytoplankton in coastal waters 7. Fe and Al (dissolved and particulate) in seawater and aerosols 8. Fe ligand profiles and siderophore incubations 9. Zooplankton in the surface layers In general this was a very successful cruise, with just 1 day lost to weather and 1 day to winch problems. Fortunately none of the winch problems were of a nature that suggested that there were any lingering long term problems with the winch system. The one major disappointment was that the mooring on the Wyville Thomson Ridge failed to come up. Another ADCP mooring that was on board the ship was deployed instead. Two undergraduate students gained seagoing experience, and three MSc and six PhD students collected data for their research projects. The headline early result from the cruise was that whilst the temperature of the upper 800 m of the Rockall Trough was slightly cooler than in 2008 and 2007, there was no strong indication that the long term warming of these waters has come to an end. All data from this cruise are due to be banked with BODC, either directly after the cruise, or when they are processed, as appropriate. DVDs of the data were made available to the PS and other senior scientists. A weblog of the cruise was kept and can be found at www.sams.ac.uk.