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Lately, it has been super busy as we had back-to-back stations with lots of science operations running round the clock. Now that we have wrapped up our operations in the Labrador shelf and have also completed our station in the center of the Labrador Sea, our next series of stations will be close to Greenland and inside some of the Greenland Fjords. Over the last few weeks, the ship has become our home. During this time, we also experienced things that are quite unique, and today’s blog is about a few of them. Also, please enjoy a video of pilot whales below! Foghorn! It is not uncommon to have dense fog in the middle of the ocean. The fog reduces visibility and therefore the ship needs to use sound to warn other nearby vessels of its presence and to avoid collision. So, this is like a car horn in some respect. However, there is a lot more to it than just letting other vessels know of its presence. For example, a small vessel will have a higher-frequency foghorn sound, and a larger vessel will have a lower-frequency sound. So, another vessel in the vicinity that cannot see us would not only know about the presence of another vessel but would know about the size too. These are the technical aspects of the foghorn, now let’s talk about our experience of trying to sleep with the foghorn, which is blown every two minutes. Boy, it is loud!! Some of us scientists are in rooms that are close to the foghorn by the bridge (from where the captain and mates drive the boat), and the foghorn has been a revelation. The foghorn rattles the walls every time it blows, and it goes on as long as there is fog around (which can be for days). After a day or so, we got used to the rhythmic blowing of the horn and then it stopped as the fog cleared. Now the absence of the foghorn is difficult to bear. Survey sound As part of our work, we use sound to survey the ocean bottom. These instruments produce periodic sound pulses, which travel to the bottom of the ocean and come back to a receiver on the boat. The two-way time of sound allows us to estimate the depth at a point. We do this over and over and when all of these depths are put together, we can create a map of the ocean floor. One of these sound sources (3.5 kilohertz) can also penetrate a little bit into the ocean bottom, allowing us to gauge what type of materials are at the bottom. We heavily depend on this type of survey to decide where to collect sediment versus when to move on. Scientists whose living quarters (called state rooms) are close to these sound sources hear periodic ‘chirps’ as we survey along. Time changes Since we left Woods Hole, we have had three time changes. The last two time changes were within one week. We are currently three hours ahead of the US eastern time. Every time there is an impending time change, the crew would put signs all around the vessel and come change the clocks. All time changes happen at night and as a result the night shift worked one hour less, and the day shift had one less hour of sleep. Sorry, day shift! AuthorChandranath Basak Comments are closed.
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