DAY 15: SCIENTIFIC EXPLORATION IN THE 21st CENTURY!
13.07.2008 Jules Verne published TWENTY-THOUSAND LEAGUES UNDER THE SEA in 1870. The Nautilus was full of mysterious dials; I remember it vividly pictured in my child’s copy of the book. The operations center for our trip beneath the sea is not so colorful as Verne’s imagination, but I think even this most imaginative “father of science fiction” would be amazed by its complexity!
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text and photos by Courtney Flanagan
The CTD has been sent down about 24 times by count of Instrument Chief Martin Dahl. For the last five or so drops, it has also been "yo-yoed" - sent up and down - about five times each trip. On each drop, each CTD bottles is opened at a different spot. The smaller CTD has 12 bottles, the larger 24. The results of each test, including information on where the sample was taken, are in part reflected in a graph on the computer screen like the one in the picture. As I understand it the possible measurements include:
The CTD activity has taken place day and night on this ship. Each drop of the CTD is a time consuming process: it takes a while for it to get to depth, a while to complete the actions, and a while to come up. And then it is analyzed by graduate student Kristin Fresland. The ship makes navigational choices based on the findings, and each result is carefully studied as slowly, very slowly places are eliminated that are not of interest. This work is definitely a process of elimination. As places are eliminated where a vent is very unlikely to be, the closer the scientist can come to a find.
Martin also told us something about the mapping project that has been going on during our entire time at sea. The first picture in the grid shows the area mapped by the ship's sonar. The small dot (hard to see) is the ship, and the large red box is the area being mapped. This is achieved by 135 sound beams sent out from each side of the ship. They fan out and cover an area about 2 kilometers wide on either side. The second chart shows the position under the ship of the transmitter and receiver for each beam. The transmitter box sounds out the beam, and the receiver box ......receives it!
All of this data needs to be corrected for the movement of the ship. Our very advanced navigation system takes into account the pitch, role, yaw etc. of the ship and adjusts the beam to account for it. The system also corrects error in the GPS.
On the third screen in the series, you can see the way the computer takes the information from the beams and from the navigation system and stores it as a layer on the topographical map. More specific calculations are made later to the x and y map coordinates.
Jules Verne could only imagine what lay beneath the sea, or in the center of the earth! Thanks to the combination of new technology, and human skill at operating and interpreting the data, we can truly begin to know.
White line: Water temperature
Red line: Density of the water. The greater the depth, generally the greater the density.
Green line: Number of particles in the water. This is figured by interruptions in a beam light. The greater the interruption, the more particles.
Blue line: Measurement of reduced compounds in the water. These are compounds that can give away electrons easily. Two of these are methane and hydrogen, presence of which in the water often indicates hydrothermal vents.
Anomalies in the expected curves on the graph might indicate possibility of hydrothermal activity.
