Two Russian explorers have set a record for the deepest ice dive in the White Sea in the far north.

Maxim Astakhov and Alexander Gubin of the Russian Geographical Society descended 102 metres (335ft) beneath the sea ice on Saturday while testing new scuba-diving equipment, the society told Interfax news agency.

During the 80-minute dive, the water temperature in the White Sea, the bulk of which lies just outside the Arctic Circle near Arkhangelsk, was -1.5C (29F). Although the temperature is below freezing, the water remains liquid because of its salt content.

“It was not completely dark, not what I expected,” Astakhov said after the dive, the defence ministry’s Zvezda channel reported. “It was a joy to see the living creatures that exist at the depth of 102 metres, practically on the bottom of the White Sea.”

Serbian Bozana Ostojic, a member of the World Underwater Federation and a logistics expert from late underwater pioneer Jacques-Yves Cousteau’s team, was present at the dive and confirmed the record.

In video published by Russian media, Astakhov and Gubin can be seen clambering into a hole in the ice with several air tanks strapped to their backs. Connected by ropes to a guideline and using electric torches to illuminate the way, they descended to the record depth with at least a dozen air tanks for testing. After surfacing, one of the divers can be heard saying his equipment didn’t work at first in the extreme conditions, but later began functioning.

The expedition to the White Sea is part of the Russian Geographical Society’s 13 Seas of Russia project, which began last July with a dive in the Barents Sea that reached a depth of 111 metres (364ft), reportedly setting a record for deepest dive in the Arctic. Before the latest dive, members of the Russian Geographical Society’s underwater research division completed the first dive, descending into a lake near Oymyakon, the coldest inhabited place on Earth, in 2013. They also made the deepest ever dive in Antarctica.

The Russian Geographical Society was established by Emperor Nicholas I in 1845 as both a scientific and patriotic initiative and helped explore Russia and the polar territories. President Vladimir Putin is the society’s chairman, and the defence minister, Sergei Shoigu, its president.