This record describes multibeam echosounder data collected from the Marine National Facility (MNF) RV Investigator Voyage IN2020_V08, titled "SOLACE - Southern Ocean Large Areal Carbon Export: quantifying carbon sequestration in subpolar and polar waters." The voyage took place between December 5, 2020 and January 16, 2021 departing from Hobart (TAS) and arriving in Hobart (TAS). The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter while transiting between Hobart and study sites in the Southern Ocean. The EM122 provides a 1 degree by 1 degree angular resolution. The echosounder's nominal frequency is 12 kHz. Data are stored in .all (364 files 19.7 GB) raw format for bathymetry and backscatter and .wcd (328 files 14.3 GB) format for watercolumn backscatter at CSIRO. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Tide corrections were applied to the processed data using RTK/GPS height and the EGM2008 geoid model in Qimera. Processed data had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry and backscatter grids in geotiff format. Additional information regarding this dataset, including information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes ME 70 scientific multibeam fisheries echosounder data collected on RV Investigator voyage IN2020_V06, titled "Probing the Australian-Pacific Plate Boundary: Macquarie Ridge in 3-D." The voyage took place between October 8 and November 3, 2020 departing from Hobart (TAS) and arriving in Hobart (TAS). The Simrad ME70 scientific multibeam echosounder acquired acoustic data with an effective range nominally at ~500 m, and since much of the mapping area was deeper than this, the ME70 was only run intermittently and mainly for testing purposes. The echosounder's frequency range is from 70 kHz to 120 kHz. Data are stored in Simrad *.all raw format at CSIRO. There are 65 files totalling 19.9 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset, including the settings used, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes ME 70 scientific multibeam fisheries echosounder data collected on RV Investigator voyage IN2019_V01, The availability of Antarctic krill to large predators and their role in biogeochemical recycling in the Southern Ocean which departed Hobart on the 19th January, 2019 and returned to Hobart on the 5th of March, 2019. The Simrad ME70 scientific multibeam echosounder acquired acoustic backscatter data through the water column using a configuration designed specifically for this voyage. The echosounder's frequency range is from 70 kHz to 120 kHz. The ME70 logged continuously for the extent of the voyage except during parts of the transit. Data are stored in Simrad *.all raw format at CSIRO. There are 16,350 files totalling 1.55 TB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset, including the settings used, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes ME 70 scientific multibeam fisheries echosounder data collected on RV Investigator voyage IN2018_E02, titled 'MNF Trials and Calibrations' which departed Hobart on the 3rd of September 2018 and returned to Hobart on the 9th of September 2018. The Simrad ME70 scientific multibeam echosounder acquired acoustic backscatter data through the water column as part of a series of trials and calibration testing. Data are stored in Simrad *.all raw format at CSIRO. There are 27 files totalling 2.3 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset, including the settings used, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes multibeam echosounder data collected on RV Investigator voyage IN2018_V02 ,”SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania" and "Subantarctic Biogeochemistry of Carbon and Iron, Southern Ocean Time Series site" which departed Hobart on the 03 March 2018 and returned to Hobart briefly on 12 March and finally concluded on the 21 March 2018. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information in shallow water during transits. The EM710 MKII provides a 0.5° by 1° transmit and receive angular resolution respectively. The echosounder's nominal frequency range is from 40 to 100 kHz. Data are stored in .all raw format for bathymetry and backscatter and .wcd format for watercolumn backscatter at CSIRO. There are 39 files totalling 5.93 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Tide corrections were not applied to the processed data. Processed data has had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry grid in geotiff format. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes multibeam echosounder data collected on the Marine National Facility (MNF) RV Investigator voyage IN2024_V02, titled "SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania." The voyage took place between March 31, 2024 and April 19, 2024 (AEST), departing from Hobart and returning to Hobart. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter between Hobart and the SOTS moorings site. The EM122 provides a 1 degree by 1 degree angular resolution. The echosounder's nominal frequency is 12 kHz. Data are stored in .all raw format for bathymetry and backscatter and .wcd format for watercolumn backscatter at CSIRO. There are 477 files totalling 25.6GB of raw bathymetry and 477 files totalling 27.8GB of water column data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in .all format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Processed line data are available in .gsf and ascii format, and processed bathymetry grids in geotiff format. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes multibeam echosounder data collected on RV Investigator voyage IN2017_V02, 'SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania' which departed Hobart on the 17 March 2017 and returned to Hobart on the 28 March 2017. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information in the Southern Ocean. The EM710 MKII provides a 0.5° by 1° transmit and receive angular resolution respectively. The echosounder's nominal frequency range is from 40 to 100 kHz. Data are stored in .all raw format for bathymetry and backscatter and .wcd format for watercolumn backscatter at CSIRO. There are 20 files totalling 5 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Tide corrections were applied to the processed data. Processed data has had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry and backscatter grids in geotiff format. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected from the Marine National Facility (MNF) RV Investigator Voyage IN2020_V08, titled "SOLACE - Southern Ocean Large Areal Carbon Export: quantifying carbon sequestration in subpolar and polar waters." The voyage took place between December 5, 2020 and January 16, 2021 departing from Hobart (TAS) and arriving in Hobart (TAS). The Simrad EK80 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m, at the three study locations and transit to and from Hobart . All frequencies were logged continuously for the extent of the voyage. Logging of "complex samples" occurred daily for one hour. Data are stored in .raw (6273 files 625 GB) and .idx (6273 files 63.0 MB) formats at CSIRO. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes multibeam echosounder data collected on RV Investigator voyage IN2019_V02, titled 'SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania; Subantarctic Biogeochemistry of Carbon and Iron, Southern Ocean Time Series site', which departed Hobart on the 14 March 2019 and returned to Hobart on the 5 April 2019. The Kongsberg EM710 multibeam echosounder was used to acquire seafloor bathymetry and backscatter information around Southeast Tasmania. The EM710 provides a 0.5° by 1° transmit and receive angular resolution respectively. The echosounder's nominal frequency range is from 70 to 100 kHz. Data are stored in *.all raw format for bathymetry and backscatter at CSIRO. There are 98 files totalling 4.92 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format is corrected for motion and position. Tide corrections were not applied to the processed data. Processed data had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry and backscatter grids in geotiff format. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes multibeam echosounder data collected on RV Investigator voyage IN2018_V02 , "SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania" and "Subantarctic Biogeochemistry of Carbon and Iron, Southern Ocean Time Series site" which departed Hobart on the 03 March 2018 and returned to Hobart briefly on 12 March and finally concluded on the 21 March 2018. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information. The EM122 provides a 1 degree by 1 degree angular resolution. The echosounder's nominal frequency is 12 kHz. Data are stored in .all raw format for bathymetry and backscatter and .wcd format for watercolumn backscatter at CSIRO. There are 395 files totalling 11.7 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Tide corrections were not applied to the processed data. Processed data had outliers removed. Processed line data are available in *.gsf and ascii format, and a processed bathymetry grid in geotiff format. Additional information regarding this dataset, including information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.