National Oceanic and
Atmospheric Administration
United States Department of Commerce

NOAA PMEL scientist research cruise exemplifies international collaboration

Workers prep CTD on deck of ship at sea.

Deploying CTD (Photo: Sharon Walker)

April 03, 2026

During a recent multidisciplinary expedition (February 9 - March 5), NOAA PMEL scientist Sharon Walker traveled aboard the New Zealand research vessel Tangaroa to the Brothers submarine volcano. The cruise went from Wellington to Tauranga, NZ, and included scientists and technicians representing various fields from New Zealand, Italy, UK, and U.S.

The expedition’s goal was to image the volcano's magma/melt regions and hydrothermal pathways using 25 seafloor Ocean Bottom Electro-magnetometers (OBEM) for passive and controlled-source electromagnetic (CSEM) measurements. Essential data collected will test hypotheses on processes supporting distinct vent fields and mineral deposit formation. Additional work included repeat magnetic and gravity surveys, hydrothermal plume mapping for output changes, dredging for volcanic history, and multibeam mapping to fill regional gaps.

Graph showing hydrothermal plumes mapped at latitude/longitude and depth.

Hydrothermal plumes mapped during CTD tows over Brothers submarine volcano.

The expedition was led by Dr. Cornel de Ronde of Earth Sciences New Zealand**, a long-time collaborator (1998-present) with PMEL Vents and Earth-Ocean Interactions (EOI) programs, exploring submarine volcanoes in the Kermadec-Tonga, Mariana, and Aeolian arcs, NE Lau basin, and other sites.

Other participants included scientists and technicians from University of Southampton (UK) to support the CSEM survey, University of Durham (UK) to support the OBEM instruments and deployments, UniversitĂ  di Genova (Italy) for the magnetic/gravity anomaly survey, and Earth Sciences New Zealand (formerly both GNS Science and NIWA) to support mapping and hydrothermal plume surveys (Sharon Walker led the hydrothermal plume surveys).

** Earth Sciences New Zealand is the result of a recent merger combining the NZ crown institutes of GNS Science and NIWA. Dr. de Ronde is a senior scientist from GNS Science.