Minimal effect of iron fertilization on sea-surface carbon dioxide concentrations

Reflections on my career as a marine physical chemist, and tales of the deep

This is a personal review of how one can apply the principles of physical chemistry to study the ocean and other natural waters. Physical chemistry is the study of chemical thermodynamics, kinetics, and molecular structure. My long-term interest in the chemistry of seawater is an extension of my early work on water and the interactions that occur in aqueous electrolyte solutions, which I began as part of my PhD research on the thermodynamics of organic acids in water. Over the years, I have attempted to apply the tools of physical chemistry to elucidate the structures of seawater, brines, lakes, and rivers. I have developed and continue to work on ionic interaction models that can be applied to all natural waters. Here, I reflect on how my students, postdocs, research assistants, and scientific colleagues have influenced my life, my career, and the field of marine physical chemistry. My hope was and is to use these tools to understand the molecular structures of natural waters.

A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial Pacific Ocean

The seeding of an expanse of surface waters in the equatorial Pacific Ocean with low concentrations of dissolved iron triggered a massive phytoplankton bloom which consumed large quantities of carbon dioxide and nitrate that these microscopic plants cannot fully utilize under natural conditions. These and other observations provide unequivocal support for the hypothesis that phytoplankton growth in this oceanic region is limited by iron bioavailability.

Ecosystem Experiments

Experimental manipulations of entire ecosystems have been conducted in lakes, catchments, streams, and open terrestrial and marine environments. Experiments have addressed applied problems of ecosystem management and complex responses of communities and ecosystems to perturbations. In the course of some experiments, environmental indicators and models have been developed and tested. Surprising results with implications for ecological understanding and management are common.