Polynya dynamics drive primary production in the Larsen A and B embayments following ice shelf collapse
Article first published online: 28 JAN 2014
©2013. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Oceans
Volume 119, Issue 1, pages 572–594, January 2014
How to Cite
Polynya dynamics drive primary production in the Larsen A and B embayments following ice-shelf collapse, J. Geophys. Res. Oceans, 119, 572–594, doi:10.1002/2013JC009441., , , and (2014),
- Issue published online: 26 FEB 2014
- Article first published online: 28 JAN 2014
- Accepted manuscript online: 18 DEC 2013 12:40AM EST
- Manuscript Accepted: 12 DEC 2013
- Manuscript Revised: 25 NOV 2013
- Manuscript Received: 13 SEP 2013
- primary production;
- sea ice;
 The climate-driven collapses of the Larsen A and B ice shelves have opened up new regions of the coastal Antarctic to the influence of sea ice resulting in increases in seasonal primary production. In this study, passive microwave remote sensing of sea ice concentration and satellite imagery of ocean color are employed to quantify the magnitude of and variability in open water area and net primary productivity (NPP) in the Larsen embayments between 1997 and 2011. Numerical model output provides context to analyze atmospheric forcing on the coastal ocean. Following ice shelf disintegration the embayments function as coastal, sensible heat polynyas. The Larsen A and B are as productive as other Antarctic shelf regions, with seasonally averaged daily NPP rates reaching 1232 and 1127 mg C m−2 d−1 and annual rates reaching 200 and 184 g C m−2 yr−1, respectively. A persistent cross-shelf gradient in NPP is present with higher productivity rates offshore, contrasting with patterns observed along the West Antarctic Peninsula. Embayment productivity is intimately tied to sea ice dynamics, with large interannual variability in NPP rates driven by open water area and the timing of embayment opening. Opening of the embayment is linked to periods of positive Southern Annular Mode and stronger westerlies, which lead to the vertical deflection of warm, maritime air over the peninsula and down the leeward side causing increases in surface air temperature and wind velocity. High productivity in these new polynyas is likely to have ramifications for organic matter export and marine ecosystem evolution.