Melting water from giant icebergs travelling across the Southern Ocean supports the growth of phytoplankton, which is responsible for as much as 20 per cent of the carbon trapped in the depths of the ocean.

These icebergs enhance phytoplankton productivity for hundreds of kilometers, and their effects persist for at least one month after the iceberg has passed. The melting water contains iron and other nutrients which allows the phytoplankton to grow.

The authors of the study believe these icebergs may play an outsize role in the Southern Ocean carbon cycle. The team analysed satellite images of ocean colour, an indicator of phytoplankton productivity, which were associated with a range of icebergs at least 18 km long, in the open Southern Ocean.

Original research paper published in Nature Geoscience on January 11, 2015.

Names and affiliations of selected author

Grant R. Bigg, Sheffield, Department of Geography, University of Sheffield, Sheffield, United Kingdom