E/V Nautilus Mapping and Exploration of North Pacific Seamounts During Expeditions in 2017 and 2018

TitleE/V Nautilus Mapping and Exploration of North Pacific Seamounts During Expeditions in 2017 and 2018
Publication TypeConference Abstract
AuthorsGee, L, Preez, CDu, Norgard, T, Mayer, LA, Kelley, C, King, C, Kane, R, Heffron, E, Raineault, NA
Conference Name2018 Fall Meeting, American Geophysical Union (AGU)
Conference LocationWashington, DC
Conference DatesDecember 10-14
Keywordse/v nautilus, exploration, mapping, Ocean Exploration Trust, Pacific, seamounts

The expeditions of Exploration Vessel (E/V) Nautilus for 2017 and 2018 covered wide areas of the North Pacific - ranging from south of the eastern end of the Clarion Fracture Zone, the Davidson Seamount within the borders of Monterey Bay National Marine Sanctuary, the SGaan Kinghlas-Bowie Seamount Marine Protected Area in northern Canadian waters, and west to the Papahānaumokuākea Marine National Monument. A number of these expeditions investigated some of the seamounts that exist throughout the North Pacific.

Satellite derived maps of the seafloor have revealed tens of thousands of seamounts that rise more than 1,000m or more from the seafloor. However the vast majority have not been mapped with traditional acoustic multibeam sonar and even fewer have been explored by direct observation and sampling. The number and range of seamounts are significant in understanding the oceanic seafloor processes and the variations in the plate volcanic activity. They also support some unique ecological communities, and detailed knowledge of their shape and location assists in modelling global oceanographic circulation models.

E/V Nautilus mapped the seamounts with the Kongsberg EM302 multibeam sonar and resulting sonar bathymetry and backscatter revealed significant details of their structure and variation. The high-resolution mapping revealed considerable differences in minimum depth (+/- hundreds of meters) and areal extent of some of the seamounts from the satellite maps and added to the baseline knowledge of these significant oceanic features.

An interdisciplinary team of scien­tists participated in the ROV dives of Hercules and Argus at sea and were supported from many institutions ashore via telepresence. The ROV dives to these unexplored seamounts included visual survey transects with limited sampling of the geology and biology. The Nautilus Science Communicators also extended engagement to the public via telepresence during all the ROV dives.