Edge of the Arctic Shelf

The Hunt Continues
A biting wind greeted me as I stepped out onto the weather deck this morning. The temperature has been hovering right around freezing for the past few days, and the decks and railings were slippery with ice. Snow flurries came and went throughout the day as we continued our hunt for eddies along the shelf edge using XBTs.

This question about diving in the Arctic comes from the Morse Pond School in Falmouth, Massachusetts.

Question: How long can you stay under water without freezing?

I asked the Healy dive officer, Lieutenant Junior Grade Jessica Noel, to answer this question.

Jessica: "The amount of time you can spend in the water without freezing depends on the temperature of the water and what kind of suit you are wearing. In a regular swimsuit or shorts, the water has to be above 70

F for you to be able to stay in it for a long time. Below 70

F, your body will lose heat and you will start to shiver. The colder the water is, the sooner you start to shiver. The loss of body heat is called "hypothermia." For divers, this is important because once we start getting cold, it becomes hard for us to work with tools and concentrate on what we are doing. We wear very thick wetsuits or dry suits up here in the Arctic Ocean so that we can stay in the very cold water long enough to complete our work. Up here, the water is often near freezing (about 35

F). When the water is below 40

F, we wear dry suits (waterproof suits that keep us dry by keeping the water out) with sweatshirts and pants underneath to keep us warm. This way we can stay in the water for about 45 minutes to an hour before we even start to feel a little chilly, and it would take many, many hours for us to actually freeze. If someone fell in this water (at 35

F) without a drysuit or other thermal (heat) protection, they would only live for about 6-10 minutes before freezing."

This question is from Karen in Amarillo, Texas.

Question: I was wondering how many support staff does this expedition require and what are those functions? More specifically, who does the cooking and laundry?

Answer: Hi Karen, thanks for writing. For this answer I visited to the Food Service Specialists, headed by Senior Chief Sean Forsythe. He took me on a tour of the huge storage rooms and freezers where the food is kept. He told me that when the Healy gets underway for the summer season, he is responsible for buying six months of food, plus an extra 30 days worth, "just in case we get stuck in the ice." So how much does all of this food cost? Over $300,000.. Plus, when the ship pulls into port in between science missions, like when we were picked up in Dutch Harbor, Sean buys another $20,000-$30,000 worth of fresh produce. It's amazing to me that on day 23 salads and fruit are still available. There are five food service specialists on the ship and they do all of the cooking, four meals a day for the entire time the Healy is at sea. They regularly put in 14 hour days (starting at 5:30AM) and never get a day off on the weekends or holidays. Undoubtedly they have one of the toughest jobs on the ship. Regarding laundry, there is a large laundry room in the bowels of the ship with industrial-size washers and dryers. Everyone is responsible for doing their own laundry.

Unfortunately, our sampling today did not reveal any other eddies. Overnight tonight we will find out if the first eddy we encountered is still intact. This plot shows a two-dimensional view of the temperature of the ocean along our first transect, or line of XBT stations. The X-axis is the distance along the line and the Y-axis is the depth. The eddy is clearly visible as the blob of purple (colder) water at 150 meters depth. But, eddies don't last forever--eventually they get mixed away into the basin water. We are hoping that this one is still there, so we can map it out in detail using our instruments over the next few days.