Winding down!

(by Emma)

Now that all of our CTD casts have been completed, our team has started working on other tasks, and we’ve made time in our schedule for daily Science Meetings. Hilary has invited other researchers on the ship to discuss some of their scientific research with us during these meetings. This gives us a chance to learn more about them and their experiences in depth.

On Wednesday, we learned about Chief Scientist Alison Macdonald’s research on transport of water through the Pacific Ocean using chemical signatures. Alison is a physical oceanographer, which means that she focuses on understanding the physical movement of water within the ocean. On one of her research projects, she gathered data on various cruises crossing the Pacific using CTD casts to determine at what depths a certain chemical signature was found, and how far across the Pacific the currents carried the signature. Knowing that several specific types of water, called mode waters, are formed on the western Pacific, Alison could model the paths and depths of mixing that the water experienced as it moved eastward, towards North America. 

Emma (myself), Lucy, Heather Furey, and Alison Macdonald on the CTD deck of the R/V Neil Armstrong. This photo was taken during our last sampling for the cruise, and the goal of this CTD cast was to further calibrate the sensors on the gliders which OOI deployed the week before. In the far right background, the surface mooring buoy which OOI deployed the first week is visible. It looks very small on the open ocean! Photo by Hilary Palevsky.

Besides telling us about the projects she has worked on, Alison also told us about her experience working on research cruises all over the world. She recently came back from a cruise on the Southern Ocean, where she was also serving as Chief Scientist. On many of the cruises Alison has worked on, students are given the opportunity to operate the CTD for round-the-clock casts. This cruise is a bit of an exception, as almost all of the casts have been in the afternoon or early evening hours. Alison also suggested that Lucy and I learn to operate the CTD, which was very exciting!

Operating the CTD from the main lab involves keeping track of the sensors and communicating with the winch as the CTD descends and returns. Dave Wellwood, a WHOI scientist on board to calibrate the OOI moorings, taught Lucy and I the basics of CTD operation. Lucy and I learned to how to determine the sea floor depth and how to politely ask the winch operators to move the CTD to target depths. Watching the computer monitors for continuous data from the sensors, we manually recorded the water temperature and salinity at each target depth. At the end of the cast, we save the data to the server and head out to the deck to sample, or watch others sampling. I felt quite powerful pressing buttons and firing bottles for the CTD, although Lucy was the one in charge of winch communications.

This is Lucy and Dave Wellwood calling the CTD back up to target depths for an OOI cast. Lucy communicated with the winch via walkie-talkie. 

This is Dave and I during another CTD cast, watching the graphs showing the sensors’ data as the CTD ascends. Photo by Hilary Palevsky.

Lucy and I also took a trip up to the bridge of the Armstrong, where we had a great view of the ocean. Quinton Edwards (Chief Mate) and Keenan Foley (Able-bodied Seaman), showed us the navigation system and control board. The Armstrong has a dynamic positioning system which can keep the ship in a certain position automatically, which is important for tasks such as mooring deployments. On the bridge, Keenan also told us about his other trips on the Armstrong, and his experiences navigating near Greenland, where icebergs are a greater threat. As one of the seamen on board, he stands watch on the bridge for two shifts a day and completes other necessary work on the ship.

This is Lucy standing at the controls of the Armstrong. There are several screens showing the bathymetry of the surroundings, maps of the Irminger Sea, and other important information relevant to navigating the ship. The bridge had a wonderful view of the ocean from all directions, but because it is at the top of the ship, it experiences the most rocking. 

We are already steaming back to Reykjavik, and will reach port on Sunday!

Cheers,

Emma