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Free-drifting icebergs as proliferating dispersion sites of iron
enrichment, organic carbon production and export in
the Southern Ocean

Iceberg

Project summary

Project Period: March 2009 - 2011

Supported by: NSF-Office of Polar Programs

The Murray group (B-014) component of the iceberg project is to address the following question:

What is the relationship between Fe and nutrient distributions associated with free-drifting icebergs and the organic carbon dynamics of the ice-attached and surrounding microbial communities?

We will study the organic carbon cycling abilities of the picoplankton. We hypothesize that microbial plankton will respond to changes in micronutrient regime and water column structure imposed by the iceberg. These changes will result in a greater amount of carbon production and export to the deep sea, in addition to supplying a system capable of rapid DOC utilization. The primary objective is to integrate measured microbial biomass, activity and diversity in the iceberg zone of influence (IZI) in comparison to unaffected, control areas. The second objective will be to determine the linkages between primary and secondary production in the IZI and control areas, and how the activities are related to community structure, trophic dynamics and sedimentation rates. Thirdly, microbial community fingerprints will be used as bio-signatures of water column mixing to determine biotic influences of iceberg-associated upwelling.

Links

Iron Limitation Experiment

Monterey Bay Aquarium Research Institute (MBARI) Outreach website