[youtube=http://www.youtube.com/watch?v=QJjJT3Z3vyo]
When looking at the sea during a calm day, very frequently we see linear patches with an oily look which are called «slicks». It seems as if they were standing still, but this is far from reality. During research projects COSTAS, ECOANCHOA and FRENTES, we set out to the sea to see if we could track water movement inside and arround some of those slicks. We built home made drifters by placing small GPS units on styrofoam platforms, with a submerged plastic piece to anchor them to the current, and a flag to make them easily visible. We distributed groups of 5 drifters inside, offshore and inshore of one slick, and left them drift for some time, after which we recovered them and downloaded their position data to the computer. We then plotted their positions at consecutive time intervals, and used those plots to create time-lapse movies with their trajectories. These movies reveal the extraordinary properties of slicks as potential «larval highways». As you can see, the buoys first drift toward the slick and then line up and move just like cars along a highway. For obvious reasons, we had to interrupt the experiment before the drifters reached the coast. But it is easy to see the implications: slicks may actually represent «vacuum cleaners» of the ocean, which first concentrate all surrounding floating matter, which is then carried to impact the coast. This floating matter can be plastic garbage, spilled oil, wood, jellyfishes or competent larvae of benthic organisms searching for the coast to recruit into the adult population.