Daily Journal

June 22, 2010

By David M. Lawrence

Today was a day of fatigue, especially for those involved in processing yesterday's wing-on-wing neuston tows that netted the five-gallon bucket and two triggerfish. In the wee hours of the morning – after several watches had literally counted thousands of individual plastic pieces from the two tows – science staff made a strategic decision to estimate the rest. The estimates are 23,000 pieces from the starboard tow and 9,800 from the bucket-shortened port tow.

Science crews are still recovering from yesterday's work, but they haven't slowed their pace. We've had more neuston tows, a carousel deployment and surface stations. Mercifully, the amount of plastic captured was nowhere near what was recovered yesterday.

A lot of my focus today was on preparing for class. Giora Proskurowski and I tag-teamed on a topic near and dear to my heart – the theory of plate tectonics. Plate tectonics explains much of the geography of the surface of the Earth, from the arrangement of continents and ocean basins and the distribution of life on earth to the forces that drive volcanism and most earthquake activity on the planet.

In my case, I focused on the history of ocean floor mapping and how the data from the oceans converted most of the world's geologists, many of whom were hostile to older ideas like Alfred Wegener's theory of continental drift, to the cause of plate tectonics. Giora talked about the geology of spreading centers. Today was a good day for both talks because of our position – over the Mid-Atlantic Ridge, one of the spreading centers Giora talked about, and the feature whose discovery played a major role in sparking the scientific revolution that led to the development of plate tectonics theory.

We had success of sorts on the fishing front. Shortly after class, a small white marlin took our lure. Someone thought the marlin needed a bit more time to grow up, though, so the lucky fish was returned to its watery home.

A number of volunteers and crew have been taking up craft projects lately. In an old seagoing tradition, they are making bags and other items from old Dacron sailcloth and canvas. Yesterday, captain Chris McGuire posted a list of things that the ship could use, such as a canvas winch cover, a bosun's bag, and leather fittings for one of the neuston booms. Those that take up the crafts may make things on the ship's list or just for themselves.

More and more volunteers are becoming proficient in celestial navigation. During evening twilight, a horde of eager learners grab sextants from the doghouse and shoot sights to a number of stars. (During the day, they shoot sun lines.) A smaller crowd (understandably) shoots stars during morning twilight.

The ship has modern navigational technology, such as a global positioning system (GPS) receiver, but Sea Education Association places a high value on its students and crew developing expertise in traditional celestial navigation. The only fixes plotted on the SSV Corwith Cramer's navigational charts are celestial fixes, not GPS readings. While volunteers may grumble about the pace with which they learn the skills necessary to become a good celestial navigator, none grumble about making the effort to do so.

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To read a recent Science magazine article about marine debris in the oceans (June 18 issue, "The Dirt on Ocean Garbage Patches"), please visit the Previous SEA Research page.