| EK60 Water Column Sonar Data Collected During HB0904 |
| Habitat Mapping Cruise - Hudson Canyon (HB0904, EK60). Objectives are to: 1) perform
multibeam mapping of transitional and deepwater habitats in Hudson Canyon (off New
Jersey) with the National Institute of Undersea Science and Technology (NIUST) AUV
Eagle Ray. About one half of the shelf portion of the canyon was mapped with Eagle
Ray between 2007 aboard Ronald H. Brown and 2008 aboard Henry B. Bigelow. We seek
to complete the mapping of the shelf segment of the Hudson Canyon on this cruise;
2) perform visual ground truthing of areas up to 1,000 m deep in Hudson Canyon using
the NIUST AUV Mola Mola. In particular, we will be investigating ravines in canyon
walls mapped by Eagle Ray for vulnerable deepwater coral and sponge communities, tilefish
pueblo villages, and suspected areas of methane blowouts in the canyon bottom for
vulnerable chemosynthetic communities. Such vulnerable communities may be at risk
due to overlap with deepsea red crab, witch flounder, and/or monkfish distributions.
The intention is to detect and locate vulnerable communities and also to gain experience
for development of protocols for further exploration for vulnerable deepwater habitats
in canyon and slope areas; 3) perform a series of CTD/rosette sampler casts down the
canyon to a maximum depth of about 1,200 m in the canyon axis. This will provide a
near-synoptic, 3-dimensional view of water mass interaction around Hudson Canyon and
allow collection of water samples at multiple depths for dissolved methane analysis.
The latter will help resolve the source of elevated methane previously detected in
deep water within Hudson Canyon. Possible discovery of a local seep raises the possibility
of a chemosynthetic community supported by that feature; and 4) collect ME70 multibeam
sonar data for purposes of benthic mapping in order to resolve some issues encountered
during summer 2008 cruises for that purpose. |
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