Seeing in 3-D under the Sea

A new underwater camera developed at the University of Aberdeen and Brunel University is a far cry from the disposable kind you might buy in a plastic box: it takes sharp holographic images of marine creatures--and anything else under the sea--in three dimensions. John Watson, shown right, and colleagues described the new device last week at the Institute of Physics Applied Optics and Opto-Electronics Conference in Loughborough, England. Tomorrow the holocam is scheduled to begin sea trials at the Southampton Oceanography Centre

The camera's first subjects--plankton--aren't the most photogenic, but because these organisms feed many fish, their numbers yield important information about the health of select marine environments. Scientists often count plankton by scooping up bucketfuls of seawater and sticking it under a microscope. The advantage holocam offers is the ability to see in 3-D the relative positions between creatures, showing whether they are close enough to breed, interact or eat each other.

The camera can operate down to 100 meters, taking 45 pictures per holographic plate. Its resolution is sufficient to show dense concentrations of plankton measuring a fraction of a millimeter. And when its lasers are slightly reconfigured, the holocam can record even smaller, transparent organisms. During playback in the lab, the detailed images hover in space. Future missions for the holocam may include examining pipelines, shipwrecks, oil rigs and other submerged structures.