North Atlantic Stepping Stones 2005
August 7 - September 3, 2005
Seamount chains are present in all ocean basins, potentially providing stepping stone habitats that are semi-continuous and are likely to have a fundamental impact on the faunal dispersal patterns controlling regional biogeography and the diversity of deep-sea fauna. Identifying the mechanisms that drive the distribution and evolution of deep-sea species in space and time is critically important to understand the forces that structure deep-sea biodiversity.
The New England seamount and Corner Rise seamount chain comprise a line of seamounts that extend from the eastern continental margin of the United States to the Mid-Atlantic Ridge. The New England Seamount Chain, the Corner Rise Seamounts, the mid-Atlantic Ridge, and the deep sides of the Azores platform constitute a nearly continuous series of hard substrate islands in a sea of abyssal mud extending across the North Atlantic Ocean. Major peaks rise as much as 4000 m above the abyssal plain. While the geology of the seamounts and their effects on ocean currents have been studied to some extent, the evolutionary and ecological exploration of these important habitats have only recently been addressed.
Together, our group has conducted three cruises to the western part of the New England Seamount chain using Alvin, Hercules/Argus, and the autonomous vehicle ABE. Video transects and discrete samplings have revealed habitats in which discovery of new species and range extensions from distant locations are common. The results of our explorations to date have produced tantalizing clues about how seamount faunas are distributed on individual peaks and how they are restricted to particular regions of the ocean by current patterns. But this work remains incomplete. Almost none of the seamounts we will visit has been biologically sampled by submersible or ROV before.
In order to develop a more complete understanding of patterns in the diversity and abundance of corals, the species that live in association with them, and deep-sea nekton of seamount habitats in the western North Atlantic, we are targeting the Corner Rise and western New England Seamount regions, a nearly 3,000 km-long transect across the NW Atlantic Ocean Basin. Our ultimate goal is to ascertain if seamounts function as 'stepping stones' allowing hard substrate organisms to disperse among these deep-sea 'islands' and expand their ranges across ocean basins. The Hercules/Argus ROV system will be our primary sampling tool in order to obtain high resolution imagery and discrete faunal samples from particular sites. Multibeam sonar will be used to aid in dive planning and to better understand variation in seamount morphologies and landscape patterns. These remotely-operated dives will provide seafloor samples and observations from critically important sites to assess the role of the New England and Corner Rise Seamounts in controlling the biogeography, diversity, and evolution of deep-water corals and other fauna in the North Atlantic. In addition, using experience gained from our previous Ocean Exploration and NSF funded cruises, we will develop a comprehensive educational facet that will focus on the collection and compilation of educational resources for teachers.
Updates & Logs
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