Document Type

Article

Publication Date

2019

DOI

10.1029/2018jc014773

Publication Title

Journal of Geophysical Research: Oceans

Volume

124

Issue

3

Pages

1544-1565

Abstract

The Amundsen Sea Polynya (ASP) is distinguished by having the highest net primary production per unit area in the coastal Antarctic. Recent studies have related this high productivity to the presence of fast-melting ice shelves, but the mechanisms involved are not well understood. In this study we describe the first numerical model of the ASP to represent explicitly the ocean-ice interactions, nitrogen and iron cycles, and the coastal circulation at high resolution. The study focuses on the seasonal cycle of iron and carbon, and the results are broadly consistent with field observations collected during the summer of 2010–2011. The simulated biogeochemical cycle is strongly controlled by light availability(dictated by sea ice, phytoplankton self-shading, and variable sunlight). The micronutrient iron exhibits strong seasonality, where scavenging by biogenic particles and remineralization play large compensating roles. Lateral fluxes of iron are also important to the iron budget, and our results confirm the key role played by inputs of dissolved iron from the buoyancy-driven circulation of melting ice shelf cavities (the "meltwater pump"). The model suggests that westward flowing coastal circulation plays two important roles: it provides additional iron to the ASP and it collects particulate organic matter generated by the bloom and transports it to the west of the ASP. As a result, maps of vertical particulate organic matter fluxes show highest fluxes in shelf regions located west of the productive central ASP. Overall, these model results improve our mechanistic understanding of the ASP bloom, while suggesting testable hypotheses for future field efforts.

Rights

This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivatives 4.0 International License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

Original Publication Citation

St-Laurent, P., Yager, P. L., Sherrell, R. M., Oliver, H., Dinniman, M. S., & Stammerjohn, S. E. (2019). Modeling the seasonal cycle of iron and carbon fluxes in the Amundsen Sea polynya, Antarctica. Journal of Geophysical Research: Oceans, 124(3), 1544-1565. doi:10.1029/2018jc014773

ORCID

0000-0001-7519-9278 (Dinniman)

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