This data set was acquired with a Kongsberg model EM120 multibeam sonar system during Nathaniel B. Palmer expedition NBP0409 conducted in 2004 (Chief Scientist: Dr. Ronald Kiene). These data files include Acoustic Backscatter, Sidescan, Swath Bathymetry data and were processed at sea using the open source MB-System multibeam sonar processing software. These data are included in the GMRT Synthesis, beginning with version 1. Data were acquired as part of the project(s): Impact of solar radiation and nutrients on biogeochemical cycling of DMSP and DMS in the Ross Sea, and funding was provided by the U.S. National Science Foundation.