Award: OCE-1315200

Marine Phytoplankton, the photosynthetic organisms that constitute the base of the food chain in the oceans, are responsible for nearly half of the primary production on Earth. This project is concerned with the effects of the ongoing increase in the concentration of atmospheric CO2 and the attendant acidification of the surface ocean on the physiology and growth of marine phytoplankton. We conducted a detailed study of the effects of acidification on the bioavailabilty of some trace metals (particularly zinc) that are essential to phytoplankton and sometimes limit the growth of these organisms in the ocean. Laboratory experiments demonstrated that acidification increases the bioavailability of Zn in the presence of some organic compounds, but decreases it in the presence of others. Those results are explained by the different acid-base chemistries of these organic compounds and their different effects on metal bioavailability. In addition the results of the biological experiments could be matched quantitatively with purely chemical measurements of the chemical reactivity of the metals using electrochemical analytical techniques. Results obtained in the course of this project are clearly advancing our understanding of the effect of increasing CO2 on the physiology and ecology of marine phytoplankton and primary production. In addition, our work is elucidating fundamental processes that are at the core of the fields of algal physiology and biological oceanography. Over the years, several postdoctoral researchers, doctoral students and undergraduate interns worked on this project which provided an excellent platform to further their training and scientific development. Most of these people have obtained good university positions (as faculty members, postdoctoral researchers and graduate students) which allow them to pursue careers in science. These young people are now part of a cadre of young environmental scientists and oceanographers who will develop a molecular understanding of environmental and oceanographic processes. Last Modified: 01/03/2017 Submitted by: Francois M Morel