NOAA Teacher at Sea
Onboard USCGC Healy
August 7 – September 16, 2009
Mission: U.S.-Canada 2009 Arctic Seafloor Continental Shelf Survey
Geographical area of cruise: Barrow, AK, 71°18N 156°47W
Date: August 7, 2009
Cloud cover: Overcast
Winds: E, 17 mph
Science and Technology Log
Although the primary mission of this trip is to map the ocean floor, there are also other scientists on board doing other research. Ethan Roth is doing just such research. He is from the Scripps Institution of Oceanography in San Diego, California. Ethan’s specialty is ocean acoustics. He planted two acoustic sensors on the seafloor in September of 2008 and today he retrieved both instruments. This device is known as a HARP (High-frequency Acoustic Recording Package). Basically, this instrument has been “listening” to the sounds of the ocean north of Barrow for almost a year. The HARP sat at a depth of about 300 meters for all this time and today it saw daylight for the first time! The seafloor frame sits on a steel plate, which act as ballast to keep it under the water and moored to the seafloor. When Ethan wants it to surface, he sends it an acoustic signal to release the ballast and the HARP floats up to the surface. A small rigid hull inflatable boat (RHIB) is used to retrieve the instrument and tow it back to the ship where it is lifted aboard.
You might be wondering why anyone would care what kinds of sounds are happening underwater in the Arctic Ocean. When the surface is frozen with sea ice, it is a very quiet place. The ice/water interface acts differently than the ice/air interface. The acoustic environment of the Arctic Ocean may be changing due to the disappearance of much of the multiyear sea ice. In addition to losing the insulating quality the ice has for sound the amount of human activity is likely to change, as there is less ice. As the ice begins to disappear, shipping and exploration will likely increase, adding more sounds to the ocean. Less ice means more noise in the ocean environment AND less ice will mean more human activity and even MORE NOISE. It is unknown what effect this might have on marine mammals, such as whales that depend on sound for survival. Organisms in the Arctic have evolved in a certain acoustic environment. They use sound as a tool to obtain food, migrate and communicate. If the Arctic becomes a much noisier place, how will this impact their lives?
In any science endeavor it is important to collect “baseline data”. In other words, what were things like before one of the variables changed? It is important data that these HARPs collect. Knowing the acoustical environment today can help us to interpret changes in the future.
The trip from Barrow, Alaska out to the USCGC Healy is usually accomplished by helicopter. But Mother Nature was not cooperating with us. Our fresh food (delivered by plane) and the helicopter were both delayed because of weather conditions. There was heavy smoke around Fairbanks due to forest fires and fog elsewhere making flying just too risky. Being a group of problem solvers, the leaders of the science team started asking around and found a landing craft that would fit our luggage, the food cargo, and us. The Healy evaluated the plan and agreed. In a wonderful act of generosity, the Bowhead Transportation Company (a subsidiary of Ukpeagvik Inupiat Corporation) offered to take our science party and cargo to the Healy and bring the “old” science party back to shore. If we had traveled by helicopter, we would have transported a few at a time and had to make many repeat trips. But, using the landing craft we didn’t have to worry about weight and the entire science party and cargo were able to travel at once. Thanks to the crew of the Greta and the Bowhead Transportation Company for getting us to our destination.