It has been suggested that production in offshore waters of the subarctic Pacific is limited by availability of dissolved Fe. Although that is not yet adequately established, the functional consequences of the limitation (if it exists) can be characterized from the results of the Subarctic Pacific Ecosystem Research (SUPER) program....
Phytoplankton biomass in high-nitrate, low-chlorophyll (HNLC) ocean regions exhibits a pronounced stability: variation occurs only within a narrow range of values. The magnitude of this variation has profound ecological and geochemical consequences. While mechanisms believed to set the upper limits to HNLC phytoplankton biomass (iron limitation, microherbivore grazing) have received...