Science Results : Daily Update

Daily Update | Current SEA Research

June 16, 2010

By Giora Proskurowski

Over the past couple of days our net tows have provided some unique plastic and non-plastic specimens. Yesterday morning our pre-dawn (0430 hours) neuston tow had an unusual "coastal" feel to it. There were several sprigs of leafy olive-green seaweed commonly known as Rockweed. This macrobenthic algae, Ascophyllum nodosum, is common in intertidal regions north of New Jersey. Additionally, this sample had an abundance of fish larvae much higher than what we'd previously observed, and an isopod. Isopods are like marine pill-bugs, and are not commonly found in the open ocean.

This tow also had significant marine-debris associated with it: 176 pieces of plastic (including several pieces of very new looking Styrofoam – we don't often see Styrofoam that hasn't been substantially weathered and broken down), and 3 pencil-eraser sized tar balls. Two of these tar balls were hard and quite black, but the third was very sticky and gooey, and was more brown than black (meaning that the third was much "fresher" than other two).

While it is easy to imagine that when water empties into the ocean from a river or a bay it is immediately mixed into the waters of the greater ocean basin. In reality – this still amazes me – that volume of water remains intact enough to retain its unique properties for years as it slowly moves around globe. From this tow we can speculate that we sampled a small watermass (an eddy) that had recently, perhaps as recently as 30 days or so, been somewhere along the eastern edge of the U.S.

As a bonus, our midnight neuston tow (an SEA tradition) yielded a lost dragonfish. This mesopelagic fish typically lives in the deep sea, well beyond the reach of light. So while it is uncommon to get one in a surface tow, we always welcome the opportunity to take pictures of these barbed, fanged, and fluorescing creatures.