Melting icebergs linked to carbon dioxide absorption

By Lucy Brake - 27 Mar 2011 16:29:0 GMT
Melting icebergs linked to carbon dioxide absorption

A research team funded by the National Science Foundation (NSF) has found that Antarctic icebergs melting in the Southern Ocean are raising chlorophyll levels which in turn may increase the rate of carbon dioxide absorption. The new findings have major implications for global climate research and management.

Professor John J.Helly, lead author of the research paper, explains that the results show icebergs are highly likely to have an influence over the dynamics of phytoplankton in the area called ''Iceberg Alley'' to the east of the Antarctic Peninsula.

The research team has documented a persistent change in the characteristics of the surface water once an iceberg has passed through.

According to Professor Ronald S. Kaufmann, a co-author of the report, these findings demonstrate clearly ''that icebergs influence oceanic surface waters and mixing to greater extents than previously realised''.

The researchers sampled areas around large icebergs over a period of time and found that after the icebergs had drifted away there was an obvious increase in the chlorophyll levels and a corresponding reduced concentration in the levels of carbon dioxide. The findings conclude that icebergs encourage phytoplankton growth and increase the removal of carbon dioxide.

The same research team previously highlighted the critical role icebergs play as giant 'oases' of the ocean, carrying nutrients for sea life and providing important habitats for the phytoplankton web, krill, fish and communities of seabirds.

Additionally, they discovered the iceberg ''halo effect'' which refers to when the terrestrial material trapped in melting icebergs radiates out for more than two miles from where the iceberg has melted, significantly increasing the nutrient levels in the surrounding water.

''These new findings amplify the team's previous discoveries about icebergs and confirm that icebergs contribute yet another, previously unsuspected, dimension of physical and biological complexity to polar ecosystems'', said Roberta L. Marinelli, director of the NSF's Antarctic Organisms and Ecosystems Program, adding that these latest results show a direct connection between the icebergs and the carbon cycle in the Southern Ocean.

This work has helped to bring attention to the world that icebergs are not only important to marine ecosystems but now also to global carbon management processes.