As the Oden continues to cruise southwest through the Southern Ocean, the ice floes are growing larger and the sea ice is getting thicker. That is exactly what everyone on board has been hoping for, because that will allow for a full science station on the ice, instead of the "only 4 people allowed on the ice" day we had yesterday. As the ship breaks thorough the thicker ice, you feel a shudder or shake, similar to hitting a wave on the open ocean, but there is no rocking or rolling motion. The officers set the course to go basically in a straight line, but they will change course slightly to follow a "lead," or opening in the ice. I went out onto the bow of the ship and watched the Oden gliding over huge sheets of ice. At first there are no visible cracks, but then a narrow crack appears, traveling quickly away from the ship towards the edge of the ice floe. The crack widens and the ice floe begins to break into two or more pieces.
The Oden slides over the ice floes, creating large cracks which split the floes into smaller pieces.
Some of the pieces are pushed under the ship and then "pop" up, like a cork, about mid-ship, sometimes raising almost completely out of the water before flipping over and crashing into all the ice chunks churning around as the ship moves past. These pieces of ice vary in size from less than 1 square meter to 4 or 5 square meters. Most of the ice appears to be from 1 - 1.5 meters thick, with about 20 - 40 cm of snow on top of the ice.
After the Oden rides up on the ice and breaks the floe, some pieces are pushed under the ship and emerge mid-ship, popping up out of the water like a cork.
Most of the ice floes we are seeing is "first year" ice - ice frozen last "winter" ( that's May-August down here.) Occasionally a floe will appear with weathered ridges about .5 to 1 meter high, basically a "mini mountain range" made of ice. This is "multi-year ice" - ice that has survived a summer without melting. The ridges form when two ice floes crash together and freeze. The age of the ice can be estimated by how rounded, or weathered, the ridges are. These are some of the sea ice properties we are recording when our team does its hourly sea ice observations.
Multi-year ice can be identified by weathered ridges, like mini mountain ranges, visible on the ice floes.
Today the captain found an ice floe that was much larger than yesterday's, and comprised of much thicker ice. That allowed the crew to anchor the Oden to the ice floe and deploy the ship's gangway. This meant that all the science teams could go ashore as needed to complete their work, and even the "visitors" (crew and support staff) could go ashore to sight-see and observe the science teams.
First Blake and Brent took the EM Profiler (the device that measures sea ice thickness) and surveyed an area of flat, consistently thick ice where the other teams could set up their sampling sites. This was important because when the other teams need to cut out an ice core or collect sea water samples, it is best to use a flat area of 1-1.5 meter thick ice, not a ridge where the ice may be 2.5 or 3 meters thick!
While David and I waited for Blake and Brent to finish, we watched the seal team launch the Zodiac boat off the Oden's back deck and motor off in search of seals. The helicopter was grounded today due to fog, so the Zodiac became the preferred mode of transportation out to the nearby floes, where we could see several crabeater seals dozing on the ice.
The Oden's seal research team takes the Zodiac out in search of seals.
We went ashore after lunch, hauling our gear out to the study site on a plastic sled. The sled proved very helpful because the study site was about 250 meters from the ship, and we carried two large hand augers, marking flags, several 25 and 50 meter tape reels,the EM Profiler and our backpacks and personal gear. The snow depth varied from 5 cm to 40 cm in some spots and several times we sank up to our knees in snow.
Blake measured out two 100 meter transects - a transect is a measured line in a predetermined heading at which measurements or data is recorded at regular intervals - which crossed in the middle like a big X and he surveyed the transect lines with the EM Profiler while David, Brent and I drilled holes through the sea ice to the water every 20 meters and recorded the ice thickness and snow depth at each hole.
David Prado and Brent Stewart drill through the ice to measure sea ice thickness.
Anne Maire Wotkyns measures the sea ice thickness on an ice floe in the Antarctic.
When we finished our work, I was able to take some pictures of Pascy, the Monlux Magnet School Room 14 mascot who has been traveling with me and my students on some fun adventures. Pascy is named for Pascagoula, Mississippi, the town in which I purchased him and where we began our adventures together. He even has a journal chronicling his activities. I hope to add many new pages to his book during this expedition. Pascy watched some of the other teams taking their snow and ice samples.
Pascy the Penguin, Room 14 mascot, watches a science team collect ice, snow, and water samples.
Then, Pascy helped me hang all the flags I brought with me. Many different schools, classes, and community groups made these flags, which have already flown in Punta Arenas, Chile, and now on an ice floe in the Southern Ocean. It was quite breezy which makes it hard to see the designs on all the flags, but they are all there. Can you find your flag? Keep reading my journals - I will fly the flags several more times and post more pictures of them
Anne Marie Wotkyns displays some of the class and community flags she brought with her to the Antarctic.
Classroom and community flags on an ice floe with the Icebreaker Oden in the distance.
Classroom and community flags on an ice floe with a polar research scientist in the background.
Lesson Learned: A day of work on the ice can be very rewarding!