Speed 9.2 knots (kts) Course 316° Location Canada Basin, 76.80° N, 147.41° W Depth 3821 meters
SPECIAL FEATURE DISCUSSION:
(see previous journal for the questions.)
The deepest features in the Earth's oceans are oceanic trenches. Some exceed 10,000 meters deep, with the Marianas Trench in the western Pacific Ocean exceeding 11,000 meters (nearly 7 miles) at its deepest point.
The multibeam sonar projects out at an angle to each side of the ship. As water depth increases the sonar beam spreads out farther, mapping a wider swath. We are currently mapping a swath about 10,000 meters wide in water about 3800 meters deep.
TODAY'S JOURNAL:
This morning we did a deep-water CTD cast, recording conductivity (to determine salinity), dissolved oxygen, fluorescence (to determine chlorophyl content), and temperature to a depth of almost 3800 meters and then recovering 24 water samples in Niskin Bottles on the way back up. I took advantage of the nearly 3-hour ship stoppage to do a simple little science demonstration. I put about 200 or 250 ml of fresh water in a plastic bottle, capped it, and tied a line to the bottle (with a little tape over the knot for insurance.) Then I put the bottle overboard to let it float in the Arctic Ocean for a while. After about an hour and forty-five minutes I pulled in the bottle and the water inside had almost completely frozen. Clearly, the surface water temperature at our location was below 0° C (32° F), the freezing point of water.
Plastic bottle with fresh water, tethered and ready to cast into the Arctic Ocean.
Our water bottle floating in the liquid Arctic Ocean.
After about an hour and forty-five minutes, the water in the bottle had frozen. I cut the bottle open and dumped the ice out onto the deck to see it better.
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SPECIAL FEATURE:
How can the water in the Arctic Ocean be below 0° C yet remain liquid?
That's all for now! Best- Bill