Photoquadrats

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Epilithic organisms in a photoquadrat at Minnesota Reef, 21m depth.  You can see cup corals, several bryozoans, hydroids, sponges, encrusting algae and a creeping sea cucumber.

A lot of the work our lab does involves taking photos of quadrats underwater.  We take photos because the depth we work at (up to 27m) prevents us from spending enough time to quantify epifauna along our transects.

Our camera setup consists of an Olympus C-8080 in an underwater housing, a strobe slave, and an Ikelite strobe, all mounted on an aluminum frame.

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Photo by Megan Cook

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Photo by Megan Cook, Ryan Knowles diving

The business end of the framer measures 35x25cm.  When we take photos we rest this rectangle flat against the bottom, and use the rulers to set an accurate scale for measuring mobile fauna on the computer.  We quantify percent cover of sessile organisms by dividing the photo into 24 blocks and estimating basal and canopy cover in each block.

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