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
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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