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Images: The Waves Within the Waves

Aboard a boat in Massachusetts Bay, WHOI biologist Jesús Pineda keeps a steady vigil over his computer screen, waiting for evidence of an internal wave moving within the ocean depths. He is using a device called an echosounder, which uses sound waves to detect different densities of water masses. (Leslie Baehr, Woods Hole Oceanographic Institution)
An echosounder image shows the interface between warmer, less dense water (light blue) sitting atop colder, denser water below (dark blue)—and a possible internal wave propagating along the interface. (Jesús Pineda, Woods Hole Oceanographic Insitution)
In search of internal waves, scientists look for alternating bands of rough water and slicks of smooth water on the ocean surface. The rough water forms when when internal waves move downward within the ocean; the smooth slicks form when internal waves move upward. (Leslie Baehr, Woods Hole Oceanographic Institution)
The research team’s study area is Massachusetts Bay near the tip of Cape Cod and Stellwagen Bank, a large underwater plateau to the north. The combination of tides and seafloor topography generates internal waves.
A satellite image show alternating dark and light ripples of rough and smooth water formed at the ocean surface by internal waves. The bands are rippling into Cape Cod Bay between the tip of Cape Cod and Stellwagen Bank. (José da Silva/the University of Porto in Portugal and the German Aerospace Center's TerraSAR-X satellite)
WHOI physical oceanographer Karl Helfrich (above) and visiting scientist José da Silva from the University of Porto in Portugal took another look at satellite image archives and noticed previously unseen internal waves forming in Massachusetts Bay. Helfrich says internal waves play powerful and still unknown roles in transferring heat, energy, water masses, and nutrients throughout the ocean. (Tom Kleindinst, Woods Hole Oceanographic Institution)
WHOI biologist Jesús Pineda’s interest in internal waves is his hypothesis that the waves may concentrate plankton, attracting fish and aggregations of whales that feed on the fish. (Leslie Baehr, Woods Hole Oceanographic Institution)

WHOI researcher Vicke Starczak records times when internal waves appear, when fish and sharks appear on the underwater video camera and on the echosounder, and when whales and small fish are present on the surface.

(Leslie Baehr, Woods Hole Oceanographic Institution)
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