Abstract

Carbon monoxide (CO) and carbon dioxide (CO2) are the two major oxidized products of DOC photo-oxidation by sunlight. The CO cycle has long been studied, recently more quantitatively by our lab on global and local scales. Intensive studies of diurnal and seasonal CO cycles at BATS (project DIEL, two cruises) revealed unexpected features of CO photo-production, microbial oxidation dynamics, and CO redistribution in the upper water column by vertical mixing. In contrast, CO2 production ("photo-CO2") was only recognized recently as a major photoproduct of terrestrial DOC. Later, its oceanic production has been suggested to be ~1015 gC/yr (>10% of ocean primary production!); others suggest ~1014 g C/yr - still important in the C cycle. However, photo-CO2 is very difficult to measure in seawater due to ubiquity of CO2 contamination. A new method for measuring photo-CO2 it will be described and progress towards implementing it will be summarized. Time permitting, possible uses in biological studies will be suggested.

Biographical Sketch

Oliver C. Zafiriou (B.A. Oberlin '62, M.S. / Ph.D. Johns Hopkins (Chemistry '63/'66)) spent two postdoctoral years studying mechanistic photochemistry (with J. Saltiel, FSU, and others, JHU), and one year as a sabbatical-replacement chemistry Professor ( Haverford College ). He then joined the Woods Hole Oceanographic Institution in fall 1969 to work with Max Blumer, isolating and characterizing the chemical attractant(s) that enable starfish to find oysters - an area in which he was admittedly and totally unqualified. Realizing only after two years that there were few papers on ocean photochemistry, not because there wasn't any, but because no one knowing much about both photochemistry and oceans had worked on it, he chose that topic; he is still at it. Aside from the major theme of inventing methods aimed at key issues in aquatic photochemistry and applying them to study the oceans, he has worked on aspects of atmospheric chemistry and microbial biogeochemistry (N cycle, CO oxidizers). Turning to another field in which he is admittedly and totally unqualified, his latest interest is particle photochemistry and photobiology.

Light refreshments are served in the Interaction Area (4th floor of the Oceanography/Physics Building) at 4:00 p.m.

All seminars begin at 3:00 p.m. and are held in room 200 of the Oceanography/Physics building.