A fleet of icebreakers, under the auspices of the Integrated Ocean Drilling Program (IODP) successfully drilled in deep water of the central Arctic Ocean, near the North Pole (Fig. 1; Moran et al. in press). The Arctic Coring Expedition (ACEX) was the first expedition to drill in the central Arctic Ocean where heavy sea ice prevails year-round. The goal of ACEX was to drill and recover the first paleoceanographic sediment record from the central Arctic Ocean (Backman et al., in press). In August 2004, three icebreakers met at the ice edge, and headed north, as a convoy, to begin ACEX. This expedition successfully recovered core in water depths ranging between 1100 to 1300 m. The project involved over 200 people, including scientists, technical staff, icebreaker experts, ice management experts, ship's crew, and educators. At the drill site, temperatures hovered near 0° and occasionally dropped to -12°C. Ice floes 1 to 3 meters thick blanketed over 90% (i.e., >9/10 ice cover) of the ocean surface, and ice ridges, several meters high were encountered where floes converged. The ice drifted at speeds of up to 0.3 knots and changed direction over short time periods, sometimes within an hour. The Swedish diesel-electric icebreaker Vidar Viking was converted into a drill ship for this expedition by adding a geotechnical drilling system that was capable of suspending over 2000 m of drill pipe through the water column and into the underlying sediments and by creating a hole in the hull (moonpool) capable of accommodating the drilling system. The two other icebreakers, a Russian nuclear vessel, Sovetskiy Soyuz, and the Swedish diesel-electric Oden, protected Viking by circling upstream in the flowing sea ice, breaking the floes into smaller pieces to protect the drilling vessel so that it could maintain station.
Figure 1. Map of the Arctic Ocean with the location of the ACEX sites shown (red circle). Bathymetric map is the International Bathymetric Chart of the Arctic Ocean, compiled in 2001. (available in fullpaper)
Despite thick and pervasive ice cover, the fleet and ice management teams successfully enabled the drilling team to recover cores from three sites. Ice conditions became unmanageable only twice, forcing the fleet to retrieve the pipe and move off location until conditions improved.
The Deep Sea Drilling Project (DSDP) was the first to sample the deep subsurface of much of the global ocean. DSDP operated the drill ship GLOMAR Challenger, the first ship to drill in ultra-deep water (>3000 m). The Ocean Drilling Program (ODP) began in 1985 operating a larger and more capable drill ship, the JOIDES Resolution. These two programs made fundamental discoveries and made major advances in earth and ocean sciences. DSDP and ODP drilled over one thousand sites from every major ocean basin except the Arctic. ODP ended in 2003 at the same time the follow-on program, IODP, began. IODP expands the capability of scientific ocean drilling with the addition of a deepwater riser ship (provided by Japan) and mission-specific platforms (provided by Europe).
