Deep vision

A new type of underwater camera sees more than ever before.

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Jaffe Lab for Underwater Imaging

Dive photography stepped up a notch when a United States diver built a camera that can record animals on the seafloor as tiny as a tenth the size of a human hair.

The camera, designed by University of California San Diego PhD student Andrew Mullen, can capture detail in the field previously possible only in the lab—such as single-celled algae just 10 micrometres across that live in coral—revealing tiny interactions that together influence the marine ecosystem.

The camera uses a soft lens that focuses the way your eye does, by changing shape, and a tripod for placement on the seafloor. With 2.2 micrometres its maximum resolution, it uses ‘focal stacks’ to record animals that have a deeper 3D structure.

Leaving the camera in place overnight has revealed ‘coral polyp kissing’ for the first time in the natural environment, where polyps of the same colony periodically embraced each other throughout the night, perhaps as a way to swap materials. The team also placed corals from different areas together, and overnight footage captured them ejecting extensions of their gut to digest each other.

Pocillopora Coral Under Fluorescent Illumination: The image was formed by exciting the coral with blue light and using a filter to block any returning light in the blue portion of the spectrum. The image is an enhanced depth of field composite formed from several images taken at different focus planes, the field of view is 17 x 14 mm.
Pocillopora Coral Under Fluorescent Illumination: Fluorescent image of the coral Pocillopora taken in a lab tank using the 5x objective. Zooxanthellae are emitting red fluorescence from their chlorophyll. The field of view is 1.7 x 1.4 mm.
Xenia: In situ image of a continuously pulsating soft coral of the genus Xenia taken using the 3x objective, in Eilat, Israel. The field of view is 2.8 x 2.4 mm.
Coral Bleaching: The “Coral Bleaching” shows Porities coral with different levels of zooxanthellae loss. When few or no zooxanthellae can be seen in the coral the polyps have a translucent appearance. While translucent, the polyp structure and tentacles remain intact and visible, indicating that the polyp is still alive. In situ, the 3x lens was used providing a 2.82 x 2.36 mm field-of-view.

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