This record describes scientific split-beam echosounder data collected on the 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 Simrad EK60 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a 1500 m range, around the southwest of Tasmania. All frequencies were logged continuously for the extent of the voyage. The frequencies were set to passive for periods of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 2,748 files totalling 91.5 GB of raw data in this dataset. 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 scientific split-beam echosounder data collected on the RV Investigator voyage IN2021_V02 (SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania), which departed Hobart on the 14th April 2021 and returned to Hobart on the 28th April 2021. The Simrad EK80 wide band transceivers (WBT) 38, 70, 120, 200 and 333 kHz, as well as the EK60 split-beam GPT 18kHz were used to acquire acoustic backscatter data to a range of 1500 m, during the voyage. All frequencies were logged sporadically (only when transiting) for the extent of the voyage. The frequencies were set to passive for the periods when stationary during the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 422 files totalling 40.6 GB of raw data in this dataset. 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 scientific split-beam echosounder data collected on the RV Investigator voyage IN2022_V03, "SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania", which departed Hobart on the 4th May 2022 and returned to Hobart on the 15th May 2022 (AEST). The Simrad EK60 split beam GPT for 18kHz and Simrad EK80 split beam WBTs for 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m during transits. All frequencies were logged continuously for the extent of the voyage, except for periods of mooring recovery/deployment when all acoustic systems were mandated to be suspended to communicate with the mooring beacons. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 436 files totalling 41.5 GB of raw data in this dataset. 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 scientific split-beam 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 Simrad EK60 split beam echosounders for 18kHz and Simrad EK80 split beam echosounders for 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m from Hobart to the SOTS moorings sites and during the return transit. All frequencies were logged continuously for the extent of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 783 files totalling 73.7 GB of raw data in this dataset. Calibration values from the IN2023_E03 calibration were applied on acquisition. IMPORTANT NOTE: The 18 kHz transducer had a faulty channel for the duration of this voyage. Although data was logged, the 18 kHz data should NOT be used for quantitative analysis. 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 scientific split-beam echosounder data collected on the RV Investigator voyage IN2023_V03, SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania which departed Hobart on May 12, 2023 and returned to Hobart on the May 25, 2023. The Simrad EK60 split beam echosounders for 18kHz and Simrad EK80 split beam echosounders for 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m, between Hobart, the SOTS location and while on site. All frequencies were logged continuously for the extent of the voyage. There was a dedicated acoustic survey over the Patience Seamount while transiting to SOTS and also some opportunistic noise data collection to compare EK60 and EK80 noise levels. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 1130 files totalling 53 GB of raw data in this dataset. 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 scientific split-beam echosounder data collected on the RV Investigator voyage IN2018_V07, SOTS: Southern Ocean Time Series Automated Moorings for Climate and Carbon Cycle Studies Southwest Tasmania which departed Hobart on the 20/08/2018 and returned to Hobart on the 25/08/2018. The Simrad EK60 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m, between Hobart and the mooring deployment site and return. All frequencies were logged continuously for the extent of the voyage. The all frequencyies were set to passive for the whole of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 591 files totalling 19.2 GB of raw data in this dataset. 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 scientific split-beam echosounder data collected on the RV Investigator voyage IN2020_V09 (SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania), which departed Hobart on the 27th August 2020 and returned to Hobart on the 12th September 2020. In addition to the tasks at the SOTS site the voyage also recovered a Rintoul mooring that was deployed during IN2020_V05. The Simrad EK80 wide band transceivers (WBT) 18, 38, 70, 120, 200 and 333 kHz, as well as the EK60 split-beam GPT 18kHz were used to acquire acoustic backscatter data to a range of 1500 m, during the voyage. All frequencies were logged sporadically (only when transiting) for the extent of the voyage. The frequencies were set to passive for the periods when stationary during the voyage. Note: the EK80 18kHz WBT failed at 12:06 on the 28th August 2020 (UTC) and was no longer used for the voyage. The 18kHz transducer was changed over to the EK60 GPT for the remainder of the voyage (in place of the 18kHz WBT). Data are stored in .raw, .bot and *.idx format at CSIRO. There are 291 files totalling 27.7 GB of raw data in this dataset. 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 scientific split-beam echosounder data collected on the 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 Simrad EK60 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 0-1500 m, around Southern Ocean. All frequencies were logged continuously for the extent of the voyage. The frequencies were set to passive for the periods during the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are [XXXX] files totalling [XXXX] GB of raw data in this dataset. 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 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 scientific split-beam echosounder data collected on the RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The Simrad EK80 split beam echosounders for 18, 38, 70 120, 200 were used to acquire acoustic backscatter data to a range of 1500 m. All of these frequencies were logged continuously for the extent of the voyage with the exception of periods of mooring triangulations. The 333 kHz was set to passive for the duration of the voyage due to a known issue with the transducer. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 807 files totalling 76 GB of raw data in this dataset. 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.