ABSTRACT Bruland : OCE-9811114 The PI proposes to examine phytoplankton Fe and Zn limitation in coastal upwelling areas. It is speculated that variations in fluvial input combined with physical differences in the width of the continental shelf and rates of upwelling, lead to variations in Fe and Zn concentrations that can influence phytoplankton, and in particular, diatom growth rates. The PI proposes to study trace metal cycling in the central California upwelling area in 1999 and off Peru in 2000, in close collaboration with D. Hutchins, who's research focuses more on the biological response to variations in Fe and Zn. The results of this proposal will have broad impact on our understanding of the functioning and controls on primary production in coastal upwelling regions. The Fe limitation hypothesis being studied here, is of great interest to a range of marine and non-marine scientists due to its impact on issues of ocean carbon cycling and climate regulation.