Tools
ToolsPickup, Daisy D., Bakker, Dorothee C. E., Heywood, Karen J., Glassup, Francis, Hammermeister, Emily M., Stammerjohn, Sharon E., Lee, Gareth A., Loucaides, Socratis, Queste, Bastien Y., Webber, Benjamin G. M. and Yager, Patricia L. (2025) Cold lenses in the Amundsen Sea: impacts of sea ice formation on subsurface pH and carbon. Ocean Science, 21 (6). pp. 2727-2741. ISSN 1812-0784
Preview |
PDF (2025_Pickup_et_al_OS cold lenses)
- Published Version
Available under License Creative Commons Attribution. Download (7MB) | Preview |
Abstract
The Amundsen Sea polynya hosts intense sea ice formation, but, due to the presence of relatively warm and salty modified Circumpolar Deep Water, the cold, brine-enriched water is not typically dense enough to sink to the deep ocean. A hydrographic survey of the Dotson Ice Shelf region in the Amundsen Sea using two ocean gliders identified and characterised subsurface lenses containing water with temperatures less than −1.70 °C. These lenses, located at depths between 240 to 500 m, were colder, saltier and denser than the overlying Winter Water (WW) layer. The pH of the lenses was 7.99, lower than WW by 0.02 and the dissolved inorganic carbon concentration was higher in the lenses than WW by approximately 10 µmol kg−1. The lenses were associated with a dissolved oxygen concentration greater than surrounding water at the same depth and density due to the cold temperatures increasing O2 solubility. We hypothesise that these lenses are a product of wintertime surface cooling and brine rejection in areas with intense sea ice formation. They may form in shallow regions, potentially around the Martin Peninsula and Bear Island, where intense upper ocean heat loss occurs, and then spill off into the deeper Dotson-Getz Trough to reach their neutrally-buoyant depth. This is supported by wintertime temperature and salinity observations. This study highlights the importance of shallow parts of shelf seas for generating cold dense water masses in the warm sector of Antarctica. These lenses are widespread in the region of the Dotson-Getz Trough and have the potential to sequester carbon deeper than typical in the region, alongside cooling the water impinging on the Dotson ice shelf base.
| Item Type: | Article |
|---|---|
| Additional Information: | Data availability: The glider datasets are publicly available on the British Oceanographic Database Centre (https://doi.org/10.5285/35b7832c-2432-fb41-e063-7086abc0c610, Heywood et al., 2025). The pH dataset from SG579 is available separately at: https://doi.org/10.5285/33d1f143-47b5-a7d1-e063-7086abc03081 (Pickup et al., 2025). The 2022 CTD measurements are publicly available on the United States Antarctic Program Data Center: https://doi.org/10.15784/601785 (NSF/NERC ARTEMIS and ITGC TARSAN, 2024). The seal data are available at MEOP: https://www.meop.net/database/meop-databases/index.html (last access: 1 December 2024). Auxiliary data utilised in figures can be found at https://data.seaice.uni-bremen.de (Spreen et al., 2008). BedMachinev3 is available from the National Snow and Ice Centre Database (https://doi.org/10.5067/FPSU0V1MWUB6, Morlighem, 2022). Funding information; Funding from the Faculty of Science at the University of East Anglia supported DDP. This work is from the TARSAN project, a component of the International Thwaites Glacier Collaboration (ITGC) with funding from the National Science Foundation (NSF: Grant 1738992) and Natural Environment Research Council (NERC: Grant NE/S006419/1). This research has the ITGC Contribution No.: ITGC-154. We also acknowledge funding from NERC (Grant: ARTEMIS NE/W007045/1) to KH and NSF (Grant: 1941483 and 1941327 – NSFGEO-NERC: ARTEMIS) to PLY and SES. Funding to UEA (NERC: Grant NE/J005703/1 and University of St Andrews (NERC: Grant NE/JOO5649/1) facilitated seal tag observations. |
| Faculty \ School: | Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA Faculty of Science |
| UEA Research Groups: | Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Climatic Research Unit |
| Related URLs: | |
| Depositing User: | LivePure Connector |
| Date Deposited: | 31 Oct 2025 10:31 |
| Last Modified: | 02 Nov 2025 07:31 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/100868 |
| DOI: | 10.5194/os-21-2727-2025 |
Downloads
Downloads per month over past year
Actions (login required)
 |
View Item |