- Speed
- 8.7 knots (we are going slower because of fog.)
- Course
- 8° (just east of north)
- Location
- 63.51° N, 168.29 W
- Depth
- 30 meters
SPECIAL FEATURE DISCUSSION
(see yesterday's journal for the questions)
Seabirds can live their whole lives in the ocean except for laying eggs and raising their chicks. In the Arctic most seabirds nest on protected cliffs or in burrows on remote islands to avoid predation from foxes.
The Aleutians are an island arc chain formed as the Pacific Plate subducts under the North American plate. This means that one part of the Earth's crust (in this case the Pacific Plate) is forced under another as the two come together at a convergent boundary. Deep sea trenches, volcanos, and earthquakes are all associated with this type of boundary.
Today's Journal:
Now that we've been underway for a while the science end of things is getting rolling. We are still in the Bering Sea (but not for long), and now is the time to make sure everything is working properly. Once we are in the Arctic we will be dealing with a more complex situation- working with another ship, breaking ice, and sailing over a more complex sea floor. All of our priority areas are in the Arctic Ocean as well, yet another reason to smooth out any kinks we can before reaching those areas. For now the sea floor is pretty flat and only gradually changes depth. We are over the North American continental shelf that connects us to Russia with relatively shallow water. During the last ice age, this was a coastal plain connecting the continents & allowing people and land animals to walk from Asia to North America or visa-versa. You may have heard of a 'land bridge' connecting the continents but I think folks picture a narrow strip with water nearby on each side when they hear that. The connection was actually hundreds of kilometers wide, and someone walking from Asia to North America could easily have gone the whole way without seeing an ocean.
The sonar watch station with me on the left followed by Steve Roberts (middle) and Tom Obrien (right.) The two monitors on the left are video feeds from the bow & stern. The other monitors are displaying information from the swath sonar, the sub-bottom profiler, and the acoustic doppler water profiler.
Yesterday I stood my first geophysical watch (a watch is a work shift on a ship.) My assignment when we are underway is to assist at the sonar watch station, which is a bank of computer monitors displaying information from the ship's navigation system and from the sonar systems we are running. A senior scientist is always on duty but the goal is to always have at least two people per watch. Partly this is to keep each other company but it also lets folks take a break without leaving the monitors unattended or to have another set of eyes and hands if things start going wrong. One system to monitor is a swath sonar which maps the sea floor well beyond each side of the ship. This lets us map a much bigger path (or 'swath') than just under the ship. Another system is the sub-bottom profiler sonar. This mainly maps right under the ship but as the name implies, this system can record features in the sediment below the sea floor. The two systems compliment each other but a pretty sophisticated computer has to coordinate the sound pulses that each system sends out ('pings') to avoid them interfering with each other. Finally, the ship runs an acoustic doppler water profiler. This instrument can map movement within the water column (the water from the surface to the sea floor.) Since the lab doesn't have any portholes there are also two monitors that feed live video from the bow and the stern so we can see what's going on outside.
Tom Obrien (left) and Steve Roberts (center) getting the sonar systems running the way they want them as I look on, trying to soak it all in.
We have had some patches of fog to cross through, but at other times the sun came out! Several people with experience sailing in the Bering Sea tell me that fog is more typical than sun. It is easy to tell when we are in the fog without glancing outside because the ship slows down to about 10 kts (from around 16 kts in clear conditions) and it sounds a fog horn every couple of minutes. I found that by standing behind the bow railing there is a little pocket of calm air (other outside decks, aka weather decks, are pretty breezy.) I think the wind is getting bumped up over the bow, creating a pleasant little zone to stand in. Besides enjoying more birding I saw something new to me- a fog-bow! There was thin fog on the sea surface but also sun coming from behind, crating this interesting phenomenon.
A fog-bow appeared for a while as the sun shone from behind me into thin fog on the sea surface.
Bill standing near the bow of the USCG enjoying some Bering Sea sun and a fog-bow.
SPECIAL FEATURE:
Why was the continental shelf between the US and Russia dry land during the last ice age but now is flooded with an ocean?
Our course indicates that we should cross out of the Bering Sea later today. What geographic feature divides the Bering Sea (Pacific Ocean) and the Chukchi Sea (Arctic Ocean)?
That's all for now! Best- Bill