Journal of Geophysical Research (1982) 87: 11,133-11,144.
Received: 3 May 1982.
Revised: 20 September 1982.
Accepted: 22 September 1982.
Published: 20 December 1982.
Lipid components in air masses were sampled during 1979 at Enewetak Atoll as part of the Sea-Air Exchange Program (SEAREX). The investigation was designed to determine the terrestrial and marine sources and to search for atmospheric transformation processes of oceanic aerosols. Four particulate lipid compound classes (aliphatic hydrocarbons, fatty alcohols, fatty acid esters, and fatty acid salts) all unequivocally show a terrestrial vascular plant source. Their temporal trends correlate well with those of other continental source indicators, such as particulate Al and Pb-210. These particulate lipids originate from wind erosion of Eurasian soil and direct emission from vegetation rather than from biomass burning, anthropogenic sources, or evaporation-condensation processes. A series of apparently marine-derived lower molecular weight alcohols and fatty acid salts and esters are also present. The more typically marine derived polyunsaturated acids are absent, probably due to their rapid rates of atmospheric degradation. A marine origin for the fatty acid salts <C20 would require marine aerosols to be enriched ca. 300-fold over the levels found in surface seawater samples. Although particulate total organic carbon data imply major influences of atmospheric transformations on the atmospheric particulate material, these effects are not observed in the lipid class compound distributions.
We gratefully acknowledge funds from the National Science Foundation, Ocean Sciences Division, under NSF grants OCE 77-12914 and OCE 81-11947 as part of the SEAREX program. We also thank the staff of the University of Hawaii's Mid-Pacific Marine Laboratory and the Department of Energy for support during the field work in Enewetak. The comments of C. Lee and J. Schneider are most appreciated. This is Woods Hole Oceanographic Institution contribution number 5103.