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Biological Processes in the Ross Sea, Oceanographic Antarctica: Paradigms Lost?
2015/6/1 2434
2015-06-05 10:00-11:30
Walker O. Smith, King’s Professor
A3-206 Zhou Long Quang Building
The Ross Sea is one of the most important regions in the Southern Ocean, contributing significantly to the biogeochemical cycles and supporting a diverse and abundant food web, characterized by the world’s largest Adélie and Emperor Penguin colonies and supporting massive numbers of baleen whales, pelagic birds and seals.  Its phytoplankton and primary productivity have been characterized as having a unimodal peak in late December dominated by the haptophyte Phaeocystis antarctica, after which the haptophyte biomass disappears and is replaced by diatoms.  Irradiance limits growth in spring, but iron limitation is common in summer. Vertical flux is substantial, and largely driven by aggregate formation. Characteristics of these “paradigms” are described.  Recent data using new and novel technologies have forced us to re-evaluate some basic features of these concepts.  Specifically, the importance of episodic events may be important in both vertical flux and phytoplankton growth.  Furthermore, while iron is reduced to low (and apparently limiting) concentrations, phytoplankton growth continues for substantial time periods after Fe becomes reduced.   The role of zooplankton vertical flux can also be important during restricted times.  The results of numerical models predicting future (+50 and +100 years) conditions suggest that drastic oceanographic and food web modifications will occur, with relatively unpredictable effects for higher trophic levels and biogeochemical cycles.   
http://www.vims.edu/about/directory/faculty/smith_wo.php



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