Scientists from the University of Maine and San Francisco State University propose to do deck-board incubation experiments in high nutrient, low chlorophyll (HNLC) waters of the eastern (Ocean Station PAPA) and the western (Ocean Station KNOT) Subarctic Pacific Ocean to determine how Fe supply affects phytoplankton species composition. Specifically, this team of scientists plans to address the following specific objectives: (1) assess how the relative availability of Fe bound to weaker and stronger classes of ligands differs among different phytoplankton groups (cyanobacteria, diatoms, dinoflagellates, prymnesiophytes) and how these differences influence the evolution of the phytoplankton community after Fe enrichment in HNLC waters; (2) ascertain if new ligands produced in response to Fe enrichment of HNLC waters behave similarly to ambient ligands, or if they have significantly different effect on regulating how an ecosystem evolves over the long term; and (3) determine whether phytoplankton assemblages in HNLC waters having different proximity or history of Fe inputs respond differently to the same suite of Fe ligand blends, or whether conditioning has led to their adaptation of alternate uptake capabilities. In addition, measurements of growth rates, macronutrient utilization rates, fluorescence, cell size determinations, Fe use efficiencies, rates of Fe and carbon uptake and flow cytometry sorting will be done to assess how specific organisms will respond to Fe supplied in different chemical forms
