Coral Forests of Disko Fan

Heading back out into Baffin Bay early in the morning of August 1st, the CCGS Amundsen navigated the ice-packed waters to get to the next sampling station, Disko Fan. Having lost satellite reception within the fjords of Baffin Island, the trip to Disko Fan was made in the hopes that the ice - which had still covered the site when the last update to the ice maps had been received - would have moved in the interim. Until actually arriving on-site, the team had no choice but to wait, and hope that the ice conditions would allow all operations to work.

Sea ice on the way to Disko Fan (Photo by Sophie Wolvin)

The Disko Fan site has a long history with Fisheries and Oceans Canada and the CCGS Amundsen scientific cruises - fisheries data in the area from 1999 showed that the deep-water habitat was filled with coral. The nets came up broken from the weight of bycatch coral, with only fragments tangled in the remains. Part of the Disko Fan Marine Refuge, the site was first closed to bottom fishing in 2008, in part to protect the cold-water corals, but mainly for its importance as a narwhal overwintering ground. Though protected, the Disko Fan corals and other inhabitants of the deep-water ecosystem were still somewhat of a mystery - so, in 2013, the first trip with a remotely operated vehicle dive at the site was completed, and the complexity of the site has had the Amundsen coming back many times since.

Keratoisis coral field in Disko Fan (Photo by the Comanche 38 remotely operated vehicle via Amundsen Science)

The Disko Fan site is also of interest for what lies above the coral forests. It is part of the nebulous boundary between boreal and polar waters, and in the plankton and fish nets that sample up and through different depths of the water column, the species in the water column start differing from what is seen in more southerly collections. The northern species are highly adapted to survive in the Arctic ocean habitat, which is influenced not only by sea temperature but also by the light; the polar summers of near-constant daylight offset by long, dark winters mean that fish and zooplankton alike need to be particularly adapted to a completely different annual cycle through the ecosystem.

Some late day visitors to the dive site (Photo by Sophie Wolvin)

A compact station, the Disko Fan site was completed in just over fourteen hours - a short time for how much data was collected through the ROV dive, sediment coring, and net sampling. The ice stayed sparse enough that all operations were able to be completed successfully, and then it was time for another long transit. Eighteen hours north up the coast of Baffin Island to a mooring deployment just outside of McBeth Fjord, and then another fourteen to the next - and final - dive site of the cruise, a site offshore of Scott Inlet.

Written by Sophie Wolvin