NOAA Teacher at Sea
Ruth S. Meadows
Onboard NOAA Ship Henry B. Bigelow
June 12 – July 18, 2009
Mission: Census of Marine Life (MAR-Eco)
Geographical Area: Mid- Atlantic Ridge; Charlie- Gibbs Fracture Zone
Date: June 17, 2009
Weather Data from the Bridge
Temperature: 10o C
Wind: 10 kts
Scientific and Technology Log
As we left St. John’s, Newfoundland, our course went through an area where icebergs were located. By the middle of the afternoon, we had several icebergs in sight. From a distance they appear to be very small white objects, but as you get closer you begin to realize how large they really are. Using equipment on the bridge, they know where the large icebergs are located well before we can see them. As we circled around them, the captain made sure we didn’t get too close.
Icebergs are masses of ice that break off of a glacier and fall into the ocean. North Atlantic icebergs originate from Greenland and are carried by the Labrador Current south until they melt. Although they look really large, you can only see a small part. The part you can see is only about 1/5th to 1/10th of the entire iceberg. Occasionally we could see seabirds on the iceberg. The weather cooperated with our viewing with clear skies and somewhat warmer temperatures. Most of the viewing was done from the flying bridge which is the top most level of the ship. It is located directly on top of the bridge which is where the navigation of the ship takes place.
As we were approaching the icebergs, most of the crew came up on the deck to see them. We could see them in a distance but it took almost an hour before we reached them. Of course, everyone had their cameras out. This is really one iceberg. The blue section in the middle is under water so it has a shallow pool in the middle. Waves break over the top and erode the ice. As the iceberg breaks up, their name changes based on the size of the chunks. Bergy bits rise 1-4 meters out of the water. Very small chunks of ice that rise only about 1 meter out of the water are called growlers.