Project Title

Formation, Transformation, and Northward Spread of Dense Saline Water Derived From Terra Nova Bay, Ross Sea, Antarctica

Summary

Event Number:
O-401-E
NSF / OPP Award 2332418

Program Director:
Dr. Marion Dierickx

ASC POC/Implementer:
Ryan Steiner / Randolph Jones

Principal Investigator(s)

Dr. Christopher J Zappa
zappa@ldeo.columbia.edu
Columbia University
Lamont-Doherty Earth Observatory
Palisades, New York

Location

Supporting Stations: Special Project
Research Locations: RV Araon (KOPRI) - South Korean Vessel, Western Ross Sea

Description

This project primarily aims to investigate the formation, transformation, and northward spread of dense saline water derived from Terra Nova Bay (TNB), along the Drygalski Trough into the western Ross Sea and off the ice shelf to the Southern Ocean, to form the Antarctic bottom water. The project will deploy a series of moorings: two heavily instrumented full-water-column moorings within TNB to capture high-salinity shelf water (HSSW) production; and a series of bottom-focused moorings to evaluate the transformation and northward spreading of the dense saline water. The broad science goals to be addressed by this program through a coordinated analysis of these mooring measurements include (1) how the water column profile and HSSW characteristics evolve on timescales ranging from hourly/daily through seasonal; and (2) what regulates the transformation and northward spread of the dense saline water derived in TNB. This project involves international cooperation between the US, South Korea, New Zealand (NZ), and Italy.

Field Season Overview

This project sees oceanographic moorings deployed and recovered across 3 years, including two heavy moorings (instrumented from the ocean floor to 50 meters [m] beneath the ocean surface in water depths of roughly 400-500 m and 800-1000 m) deployed in TNB and four deep bottom moorings (instrumented within the bottom 10-100 m of the seafloor). One deep bottom mooring will be deployed in the Drygalski Basin in TNB, one near Cape Washington in the northern extent of TNB, and two along the Drygalski Trough, further north in the Ross Sea toward Cape Adare.

In the 2026-27 season, the science team will recover the two heavy moorings and four deep bottom moorings with support from the Korean Polar Research Institute (KOPRI) aboard the research vessel (RV) Araon. The team will also deploy four low-profile moorings to be retrieved by Italian, NZ, and Korean Antarctic programs. The United States Antarctic Program will assist with moving cargo and personnel between the ports of departure and arrival of the RV Araon and storing equipment in NZ between seasons.

Deploying Team Members