First argo deploy 28 01 2025 svenja 8

Photo: Svenja Halfter/NIWA

Tangaroa voyage 2025: Weekly update

31 January 2025

The Antarctic Science Platform is the primary science funder of the RV Tangaroa's 16th Antarctic campaign, which departed Wellington on 17 January.

The team aboard the vessel has this week deployed NZ’s first biogeochemical Argo floats in the Ross Sea, expanding the international marine monitoring network. Argo floats are ocean-monitoring robots that drift in the ocean, rising and falling to depths of 1-2km at pre-programmed intervals to collect profile measurements of temperature and salinity as they drift. The "souped up" biogeochemical floats deployed this year capture even more data, including oxygen and chlorophyll levels. This new information will help fill observational gaps and begin to provide a better, year-round picture of the state of the ocean and the marine food web. Congratulations to NIWA and our Australian partners at CSIRO for collaborating with us on this milestone - the Argo programme is a truly international effort, and all data is freely available.

Argo float collage

After waiting a few nervous minutes, the team received confirmation that the floats were “talking” and operational. Photos: Craig Stevens and Svenja Halfter/NIWA.

Voyage track

The RV Tangaroa left Wellington on 17 January and the NIWA vessel will spend about 39 days at sea, including 30 within the Antarctic Treaty area (south of 60°S). The main survey area is the Western Ross Sea from Iselin Bank to Cape Adare, and as far south as the Ross Ice Shelf front. You can see the Tangaroa’s current position and daily photos on NIWA’s website.

Pengiuns on ice gert 26 01 2025

Photo: Gert-Jan Jeunen/University of Otago - Ōtākou Whakaihu Waka

Voyage science

Science objectives for the voyage include:

  • Heat, salt and meltwater fluxes in the Ross Sea, through moorings, floats and hydrographic operations
  • Benthic community sampling for biogeographic analysis, including eDNA, connectivity analysis, and resampling of historic era locations
  • NZ’s first deployment of Biogeochemical Argos
  • Polynya processes, though recovery of moorings and hydrographic operations close to the Ross Ice Shelf
  • Integration of eDNA, acoustics and direct sampling to document mesopelagic species presence
  • Zooplankton population abundance and composition
  • Biogenic aerosol production processes
  • Ocean surface biogeochemistry and bio-optics
  • Recovery and redeployment of marine mammal acoustic monitoring buoys
  • Current sources of freshwater in the Ross Sea.

These objectives align with Project 2 – Ocean Mechanics and Project 3 – Ross Sea Ecosystems, and follow on from Tangaroa voyages in 2023, 2021 and 2019, and from the NZ-Italy Ross Voyage 2024.

Impact

Our research aims to:

  • Better understand the far-reaching impacts of ice sheet melt on sea-ice, biological systems, global ocean circulation and climate informs adaptation options and critical assessment of mitigation pathways
  • Reduce uncertainty in future climate scenarios through improved understanding of how oceanic and atmospheric processes influence the cryosphere
  • Improve management of the Antarctic and Southern Ocean environment through greater understanding of the implications of regional climate change on biological systems
  • Sufficiently understand the structure and dynamics of the Ross Sea region ecosystem to forecast large scale biological responses to environmental change
  • Detect ecosystem changes in support of New Zealand’s Ross Sea region Marine Protected Area monitoring strategy and decision-making, both in New Zealand an internationally.

Collaboration

The multidisciplinary team onboard the Tangaroa includes participants from Australia, Europe, India and the UK.

The voyage is supported by funding from the Ministry of Business, Innovation, and Employment (MBIE), the Antarctic Science Platform, NIWA Strategic Science Investment Funds, University of Auckland, University of Otago – Ōtākou Whakaihu Waka, University of Canterbury and overseas funding agencies.