SOTS: automated moorings for climate and carbon cycle studies in the Southern Ocean

Voyage Number

IN2023_V03

Voyage Dates

12 May, 2023 to 25 May, 2023

Voyage Location

Hobart to Hobart

Chief Scientist

Dr Elizabeth Shadwick

Institution

IMOS

View the full voyage

Voyage summary

Research voyage to the Southern Ocean to maintain long-term deep-water automated moorings for monitoring of ocean and climate.

This voyage will contribute to global data sets and increase understanding of Southern Ocean characteristics, variability and processes. The Southern Ocean Time Series (SOTS) moorings provide year-long observations in a critical part of the Southern Ocean, where ocean interactions are most intense and least studied. This is information vital for informing ocean and climate modelling.

The primary voyage objective is to deploy a new set of SOTS moorings (SOFS-12 and SAZ-25) at 4200-4600 m depth and recover the existing SOTS moorings (SOFS-11 and SAZ-24) at 4600 m depth.

There are 4 other projects included on this voyage:

• Cloud Aerosol Precipitation Radiation Interactions eXperiment – CAPRIX (Dr Alain Protat, BOM): Ongoing program of atmospheric surveys via release of 30-40 radiosondes (weather balloons).
• Ecological and carbon sequestration role of mesopelagic organisms in the ocean (Dr Ben Scoulding, CSIRO): Net trawls of zooplankton and acoustic survey of basketwork eels on Patience Seamount.
• Oceanic latitudinal study of diatom silica production rates (A/Prof Katherina Petrou, UTS): Obtain species-specific estimates of silica production within mixed natural phytoplankton communities.
• Evolution of the Seafloor of the Australian-Antarctic Southern Ocean (Phil Vandenbossche, UTAS): Acquisition of targeted seafloor bathymetry and towed magnetometer data. 

SOTS is part of the Integrated Marine Observing System (IMOS), a global monitoring program to collect long time-series ocean data to better understand ocean and climate change and variability.

The science team on this voyage will have 29 science participants (and 20 crew) representing 6 institutions.

COVID Protocols

To safeguard the health and well-being of participants, strict COVID protocols apply to all activities on this voyage. This includes 2-phase PCR testing of all participants for COVID prior to boarding the vessel.

Voyage outcomes

As a result of this voyage, we have re-deployed the Southern Ocean Time Series (SOTS) moored platforms to provide an integrated and ongoing assessment of the seasonality of the processes that control air-sea exchanges important to climate, and upper ocean processes important to Subantarctic productivity. This analysis extends from the physics of ocean mixing and insolation, to the chemistry of ocean nutrients and the biological responses of phytoplankton, zooplankton and fish.

The SOTS research improves understanding of the global climate system by focussing on a key region – the Southern Ocean. Careful sustained observations over the last decade and into the next increases our knowledge of how the ocean interacts with the atmosphere. Improved understanding is essential to enhance advice to the nation on climate variability affecting us now, develop future scenarios and impact assessments, and to make optimal decisions that will affect the nation’s future.

This voyage contributes towards Australia sustaining the longest time series of Southern Ocean observations operated by any nation, contributing to the global effort to understand ocean dynamics and their role in climate and responses to anthropogenic emissions. It was also used as an opportunity to conduct several piggyback projects, including research to better understand the evolution of the seafloor in the Southern Ocean and gather data on the biomass of several groups of marine life.