August 22- 24- Arctic Ocean
We are hovering to the northwest of Severnaya Zemlya Island. It was an exciting morning for me! After reading and hearing so much about CTDs and moorings, I finally had the opportunity to see a CTD cast and a mooring recovery. The NABOS science team did a successful CTD test cast at 2:30 this morning. Today I will explain a little bit about CTDs.
As mentioned in an earlier post, CTD stands for Conductivity, Temperature and Depth. It is an electronic unit that contains two pumps, two temperature sensors and two conductivity meters. The CTD is the green cylinder located on the bottom of the rosette. Other sensors can be and are added to the CTD to measure such things as dissolved oxygen, chlorophyll fluorescence, turbidity, nitrate, beam transmission through the water (this helps determine particle concentrations in the water), CDOM fluorescence, PAR (photosynthetically active radiation), and a video camera system called the UVP (Ultraviolet Video Profiler). The UVP helps to identify and count different phytoplankton and zooplankton in the water column.
CDOM stands for colored dissolved organic matter and helpful in determining the concentration of organic carbon in the water. The pumps make sure there is a consistent flow of water going through the sensors and meters. There will be more conversation later about the different sensors and meters. The rosette is the white structure that holds the CTD and 24 10-liter Niskin bottles used for water sampling. Before deploying a CTD, the Niskin bottles are manually opened allowing water to flow through. Once they are in the water the bottles are closed electronically by a signal from the lab. This allows collecting data from different depths of water. The CTD also sends back data on salinity and temperature.
The purpose of the CTD test cast is to make sure everything is functioning correctly, and the hydro crew and scientists know what to do. It is like a dress rehearsal for a play. This is the time to sort out any problems. Again, teamwork is important. The hydro team oversees the ship’s deck operations- operating the crane and winch, and making sure the rosette gets over the side of the ship. One of the crew is in direct contact with the bridge to make sure the wire holding the rosette is at the correct angle so the rosette doesn’t bump into the side of the ship. This requires communication with and proper maneuvering from the bridge deck. The CTD is sensitive to the wind, and if there is too much wind the operation is called off. The CTD is being shared by all three science teams.
Breakfast: omelet, bread and butter
Lunch: cabbage soup, pork rice, and cucumber tomato salad
Tea Time: cottage cheese pastries, pears
Dinner: Stewed chicken with vegetables, pasta, mixed green salad
We woke up to rougher seas today- pitching and rolling. It has been a very busy two days on board. Science teams and ship crew working around the clock with multiple CTD casts and mooring recoveries. I talked a little bit about CTDs yesterday. Today, I will give a brief description of a mooring and will go into specifics later in the cruise. A mooring is a line with a float on top and is anchored to the sea floor. The line has instruments and floats attached at varying depths. Unlike CTDs, moorings are recovered after a long period of time. In our case, the instruments have been in the ocean for three years.
We are in the same area as yesterday, northwest of Severnaya Zemlya Island, but we are at a different mooring site. After a relatively smooth mooring recovery yesterday, today was a little bit different. The wind made it more difficult to recover the instruments and floats. There needs to be slack in the line in order to remove the instruments. The wind was blowing and the current was causing the line to pull tight. The ship’s bow thruster failed which made the ship positioning very difficult. Add wind and rain on top of that. The recovery took about six hours. It was a tough day. The length of the mooring line depends on the depth of the water. We have had recoveries ranging from 250-3,000 meters (273-3,280 yards). Information is collected electronically on the instruments and then downloaded once retrieved.
I would like to highlight one instrument today, the Upward Looking Sonar (ULS). The ULS measures ice growth. This ULS is a white cylinder about 1 m (39 in) long and 17 cm (7 in) in diameter surrounded by eight orange floats 30 cm (12 in) in diameter, in a metal rectangular frame. Rubber washer looking objects separate the floats from the frame. Can you guess what the ‘washers’ might be? (see the photo) Notice the growth on the floats?
Breakfast: porridge, ham and cheese
Lunch: mushroom noodle soup, fish cakes, rice, and salad
Tea Time: walnut salad, peach
Dinner: pork loins, sautéed vegetables, and salad
We woke up to a much calmer day at sea and have moved to a new mooring site still in the same area, northwest of Severnaya Zemlya Island. Ice was spotted from a distance. My ‘office’ has been invaded by all of these alien-looking instruments with a very curious looking growth on them. And, oh the pungent earthy smell that hits you right when you open the door to the hangar, but you get used to it.
My normal routine is to wake up, have breakfast, take my computer and a thermos of tea to my office, check the longitude, latitude and other stats, check the lab, and then settle in to write, observe and listen. This morning when I was making my rounds and stepped into the lab, John Lennon’s Imagine was playing on the speaker. This must be one of the most listened to songs in the world.
The calm weather didn’t last long!
Another lucky day! Co-Chief Scientist Heidi Kassens invited me to the bridge deck to see what happens during a mooring recovery. The bridge deck was calm and quiet and the ship was at a standstill. After watching the mooring operations on the helo deck it was interesting to get another perspective and see more of the team that is involved with moorings. The crew on the bridge deck included the Captain, Chief Officer, Helmsman, Co-Chief Scientist Heidi Kassens and Mooring Tech Till Baumann. The bridge deck reminded me of Star Trek’s Enterprise’s bridge deck, it was very modern. There was continual communication between the bridge and lower deck where the recovery was taking place. The recovery began with trying to locate the mooring by putting a hydrophone in the water. The hydrophone is both a speaker and microphone that talks to the transducer on the mooring. The transducer listens to the hydrophone and replies. It took several attempts of putting the hydrophone in the water to hear the beep that signals the mooring was found. After the beep sounded, “Wunderbar!” “We found the spot!” was heard. This was a tricky mooring because when it was deployed in 2015 there was ice on the surface so they weren’t quite sure where the mooring was located. Till Baumann used triangulation to help find the mooring. Triangulation is taking three positions in the water and figuring out where they all meet. The meeting point is where the mooring should be found. The mooring site was free of ice today, but two days ago it was covered with ice. Part of this mooring is taking place on the lower aft deck because of the wind, and the line is very heavy. The depth of the mooring is ~2,000 m=2 km (a little over a mile!). I was asked to be on lookout on the port side for the red floats that could have floated under the ship. This could cause major damage if the line got tangled in the propeller. The propeller would not be able to be fixed while we are at sea. When the first set of buoys was recovered, the bridge very carefully monitored the ship’s position and the mooring line, especially since it was so windy. This was a smooth successful recovery!
Breakfast: porridge, ham and cheese
Lunch: barley pickle soup (yummy), meatloaf with boiled eggs in the middle, pasta and salad
Tea Time: hot dogs, watermelon
Dinner: stuffed chicken breast, Idaho potatoes and salad.