Fieldnotes from the Cold Water

At eighty metres below the Norwegian Sea, red light is gone and the reef appears in shades of blue and bone. Halvard Ostrom hovers above it with a waterproof notebook strapped to one wrist and a large-format camera in the other hand.

His research group maps cold-water coral reefs, slow-growing structures that can be thousands of years old. He began photographing them to document change. He found his images reached policy makers his papers never had.

A photograph is a measurement

Every frame is shot with a calibrated scale bar and logged with depth, temperature and position. The prints are art, he says, but they are also a scientific baseline that future researchers can compare against, plate by plate.

His exhibition Below Ten Degrees has travelled to nine museums. Visitors linger in front of the largest prints, which show a reef older than most cathedrals, damaged by a single trawl.

He does not see himself as an artist. He sees himself as someone trying to make an invisible place hard to ignore.