Silicon and diatom productivity are more important than you might think

Raphael Kudela, Ph.D.
University of California, Santa Cruz

Wednesday, November 1, 2000
3:00 p.m.—Pacific Forum

Of all the potentially limiting nutrients in the ocean, only Si selects specifically against one type of phytoplankton when it becomes limiting. Diatoms have an absolute Si requirement for growth and other marine autotrophs do not, such that Si limitation affects only diatoms. It is somewhat surprising, then, that we know so little about how silicon regulates diatom growth and indirectly shapes ecosystem structure through species selection. Silicon has largely been ignored in recent years, as oceanographers focused on the role of micro-nutrients such as iron, and non-siliceous organisms such as autotrophic bacteria and the role of the microbial web. Recent technological advances have allowed us to re-examine the role of silicon in controlling diatom production, with some surprising results.

This presentation will focus on the interactions between Si metabolism and photosynthesis, and how this affects our understanding of local harmful algal bloom dynamics and global HNLC regions.

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