By Stefan Gary
The last several days have been a buzz of activity at the King George V docks in Glasgow; the RRS Discovery arrived to unload people and equipment after the end of the Extended Ellett Line cruise and take on new people and equipment for the first of this year’s UK OSNAP cruises.
This year’s Extended Ellett Line went well. We completed all the work we set out to do, didn’t have any major interruptions to our work, and even had time to collect even more data. Many thanks to the crew of the Discovery; these excellent results hinged on the close community, great conditions for life aboard, and clear communication between the crew and scientists. As we approached land, we were greeted by the sight of whales and dolphins feeding at Stanton Banks and had the opportunity to take a photo of the science team enjoying the sun on the Forecastle Deck.
In the coming months we will carefully analyze our last samples, cross check the data, produce a cruise report, and write papers. One preliminary result is that the surface waters of the Extended Ellett Line are slightly cooler and less salty than previous years. Year-to-year changes in temperature and salinity occur as the currents in this region shift position and/or strength with possible impacts on the creatures that live here and maybe even the local climate.
One way to see both the extent of the data collected as well as the interaction between the atmosphere, the ocean, and life in the ocean is the oxygen we measured below the track of the ship from Iceland (left) to Scotland (right); each black dot is a water sample (image below). The low oxygen at mid depths is created through the interplay between deep mixing caused by winter storms “renewing” the oxygen at depth and the breathing (consumption) of oxygen by animals.
The data collected during the Extended Ellett Line is an exceptionally detailed snapshot of the ocean. The ocean is ever flowing and changing so another observational tactic is to place moorings at key locations in the ocean and record data over the course of a year or more. Servicing moorings in the water is the goal of the next cruise of the Discovery – stay tuned!
Image credits: Winnie Courtene-Jones and Rich Abell.