For decades, researchers have studied how the ocean takes up atmospheric CO2 through the action of
phytoplankton that sequester carbon to the deep ocean as they continually bloom, die, and sink (a process call the “biological pump”). A large body of oceanographic research (e.g., [Boyd et al., 2007; Martin and Fitzwater, 1988]) and the geologic record [Winckler et al., 2008] indicate that the availability of iron, a micronutrient essential to photosynthesis in all plants, limits the growth of phytoplankton in large areas of the ocean. Three decades ago, John Martin and Steve Fitzwater proposed the “Iron Hypothesis”, i.e. that the deliberate addition of iron to stimulate phytoplankton growth could mimic the CO2 reduction during glacial maxima measured in ice core samples [Martin and Fitzwater, 1988]. Since 1993, twelve open ocean experiments have demonstrated that ocean iron fertilization (OIF) is one method of increasing phytoplankton biomass and, potentially increasing carbon sequestration. Given the threat posed by rapid climate change and the dominant role of the biologic pump in the Earth’s carbon cycle, it seems important that we determine conclusively whether the purposeful enhancement of oceanic carbon sinks, as well as terrestrial ones, is a possibility that is available to man—and what the impacts of doing so might be.

This document discusses the need for expanded research into OIF, highlights the key research questions, and presents some ideas on how this research can be conducted in an effective and environmentally responsible manner.