The color of the water is not intended to be exactly accurate but to remind us that most of the ocean bottom is beyond the reach of sunlight. The blackness is illuminated by flashes or glows of bioluminescent creatures, occasional glowing lava flows near the ocean spreading centers, and even more rarely (in the big picture) by lights on man-made submersibles (perhaps this could be considered a form of bioluminescence?). Fainter still, but not beyond detectors, is the brief flash of the Cerenkov Radiation from neutrinos caught traveling faster than the speed of light in water. The reaction cross-section is very low, but the detector volume (the water) is very high, and there have been serious proposals to use Photomultiplier Tube arrays to detect this radiation.
This area of the continental shelf, known as the New York Bight, is a very good area to find internal waves. Internal waves are waves inside the water. The water over the shelf becomes stratified by density differences due temperature and salinity variations. A disturbance in such stratified water will cause waves. These are not waves on the surface, they are waves in the layers of different density. Novelty stores sometimes have wave-machines, two liquids of different density in a clear container which you can rock back and forth to generate slowly moving waves in the interface between the two liquids. These waves are internal waves. In the ocean the main disturbance which generates these waves comes along about once every 12+ hours in the form of tides. As the tides slosh back and forth across the shelf break (the edge of the shelf) they generate internal waves (the outgoing tide actually makes the waves). These waves then propagate slowly toward shore. In this area (at the right times of year) several sets of waves are traveling across the shelf at the same time. They fade away when the water gets too shallow for them. Somewhat surprisingly these internal waves show up on radar images of the ocean made from satellites or aircraft. The radar certainly doesn't penetrate into the water more than a few inches, an indirect effect is in operation here. As the internal waves pass by a point they cause a variation in the surface current. This varying current interacts with the surface wind waves, either slowing them down and causing them to bunch up, or spreading them out thinner. A rougher surface reflects back more radar than a smoother one, so the internal waves can be imaged. <<< This would be a very good place for a link to an internal wave web page. I'll try to get some interest up here in putting one together. we have lots of really nice data, radar images, measurements of water density, and so on. Check back here sometime>>>.
Ray Sterner sterner@tesla.jhuapl.edu The Johns Hopkins University North latitude 39.16 degrees. Applied Physics Laboratory West longitude 76.90 degrees. Laurel, MD 20723-6099 WWW Home page: http://fermi.jhuapl.edu/res