Science Results : Daily Update

Daily Update | Current SEA Research

June 15, 2010

By Giora Proskurowski

Today was a thoroughly enjoyable day for the ship's company. At the 2300 watch change last night we shut down the diesel engine, and as Captain Chris says, "filled the sky with Dacron" (Dacron is the material the sails are made of). Suddenly the ship went quiet and immediately settled into a gentle motion moving us forward at 4 knots – and building to 6 knots over the course of the night. In the morning there were smiles all around as we steadily made our way east under plenty of sail (the four lowers, and the square sails – coarse, tops'l and raffee).

In order to get a ship with our current sail plan in position for a science station requires a highly coordinated effort led by the mates, and competent execution by the crew. So the fact that we sampled three times today means that our crew is getting some very good experience striking and setting sails, and that the mates are confident in their crew's abilities.

In addition to lots of bustle on deck to the get the ship on station, there was plenty of activity in lab. Today we spun up several additional projects, adding a microbiological sampling program (with shore support from Tracy Mincer at Woods Hole Oceanographic Institution and Linda Amaral Zettler at the Marine Biological Laboratory) and a new net tow – a Tucker trawl – into our quiver of science tricks.

A Tucker trawl is a group of three nets that we can be closed while submerged, allowing us to examine the biology and/or plastic located at a discrete depth. Today we tallied lower numbers of plastic than previous days. This is likely due to the natural unevenness of the oceans. Oceanographers often refer to the biology of the upper ocean as "patchy", meaning that organisms are often observed in clumps, separated by regions with sparse populations.

This is one reason why the term "Garbage Patch" doesn't convey an accurate image of plastic debris in the ocean. An oceanographer might understand the term "patch" to mean an uneven distribution, but the more common usage suggests the misconceptions of an "island" or "continent" of trash. I suspect that we are just passing through a region of lower plastic concentrations, following the complex variations of the open ocean.