Icebergs boost phytoplankton growth in the Southern Ocean

• Main Authors: Jill N. Schwarz, Michael P. Schodlok
• Format: Manuscript
• Language: unknown
• Published: 2008
• Subjects: Earth & Environment; Antarctic; Southern Ocean; The Antarctic; Antarc*; Ice Shelves; Iceberg*
• Online Access: http://precedings.nature.com/documents/1706/version/1; http://hdl.handle.net/10101/npre.2008.1706.1

Icebergs which calve from the Antarctic ice shelves and drift in the Southern Ocean deliver fresh water, dust and minerogenic particles to the surface ocean along the iceberg's path. Each of these components may have an effect on growth conditions for phytoplankton, as might the mechanical effects of the iceberg keel disturbing the water. Although anecdotal evidence and small-scale surveys suggest that drifting icebergs increase local primary production, no large-scale studies have reported on this possibility in detail. A combination of satellite and automated iceberg tracking data presented here shows that the probability of increased surface phytoplankton biomass was two-fold higher in the wake of a tracked iceberg compared to background biomass fluctuations. Only during the month of February were the effects of icebergs on surface biomass likely to be negative. These results confirm icebergs as a factor affecting phytoplankton in the Southern Ocean and highlight the need for detailed process studies so that responses to future changes in the Antarctic ice sheets may be predicted.