2016-2017 Science Planning Summaries
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2016-2017 USAP Field Season
Project Detail

Project Title

Impact of convective processes and sea ice formation on the distribution of iron in the Ross Sea: Closing the seasonal cycle.

Deployment of the trace-metal CTD water sampling system, which will be used by this project aboard RVIB Nathaniel B. Palmer.
Photo by: Bettina Sohst


Event Number:

Program Manager:
Dr. Peter Milne

ASC POC/Implementer:
Matthew Erickson / Adam Jenkins

Principal Investigator

Dr. Peter Sedwick

Old Dominion University
Norfolk, Virginia


Supporting Stations: RV/IB Nathaniel B. Palmer
Research Locations: Ross Sea


This project aims to fill a crucial gap in the understanding of the biogeochemistry of the Ross Sea continental shelf by assessing the roles of the late-fall convective processes and sea-ice formation in the seasonal dynamics of dissolved iron, an essential micronutrient for phytoplankton. Water column and newly formed sea-ice samples will be collected for analysis of iron and other trace metals within and en route to coastal polynyas in the southern Ross Sea during the late fall-early winter, when convective overturn and sea-ice formation begins. The samples will be collected and processed at sea and analyzed post-cruise at the scientist's home institution.

Field Season Overview

Team members will embark from and return to Lyttelton, New Zealand on the RVIB Nathaniel B. Palmer (NBP17-04) during the Polynyas, Ice production and seasonal evolution in the Ross Sea (PIPERS) cruise (C-531-N/Ackley). The team will collect and process samples from the water column, surface waters and newly formed sea ice. Sampling operations will include five to ten stations located within the coastal polynyas, and four to six stations along both inbound and outbound cruise tracks. The team will coordinate their sampling locations with the PIPERS project team. Sampling operations will employ trace-metal clean methods. The team will collect water column hydrographic data and water column/frazil ice samples using their own trace-metal clean conductivity-temperature-depth (CTD) rosette system and water samplers. They will also collect near-surface waters and frazil ice using their own trace-metal clean towfish system. In addition, if weather, sea ice, and sea conditions allow, they will collect surface seawater and frazil ice/unconsolidated sea ice by Zodiac inflatable boat. Finally, in collaboration with a Belgian group associated with the PIPERS project, they will collect samples of first-year sea ice from several locations using a power-driven trace-metal ice corer. All seawater and sea ice will be processed immediately after collection inside a shipboard trace metal clean laboratory space. Once prepped, samples will be shipped back to the project’s home institution for further analysis.

Deploying Team Members

  • Peter Sedwick (PI)
  • Bettina Sohst