Chemical Oceanography (1989) 10: 281-338.
Published: 10 December 1989.
For the past ten years, as part of the Sea-Air Exchange (SEAREX) Program, studies on the organic geochemistry of aerosols over the Pacific Ocean were conducted. In order to quantify the air-sea exchange of materials and to understand the processes that control this exchange, it was necessary to identify the sources of these materials, their transport mechanisms over the ocean and the processes affecting their fluxes across the air-sea interface. Previous reports of these studies have stressed the results from single sites. In this chapter, an overview of results from all the sites and a synthesis of these results is presented.
Samples of atmospheric aerosols and rain were collected using stringent anti-contamination protocols at five remote sites in the four major wind fields in the Pacific Ocean basin and the Peru coastal upwelling region. Enewetak Atoll and American Samoa were chosen as the sites for sampling the north and south tradewind regimes; the northern tip of New Zealand and a cruise track north of Hawaii were the sites for the southern and northern hemisphere westerlies. Samples collected at these sites were assayed for the major naturally occurring lipid classes of compounds. These compound classes were chosen because of their potential usefulness as tracers of meteorological processes and chemical phenomena.
Six classes of organic compounds were studied: aliphatic hydrocarbons, wax esters, fatty alcohols, sterols, fatty acids and long-chain unsaturated ketones. These compound classes comprise a major portion of the epicuticular waxes of land plants and a significant fraction of the lipids of marine organisms. They contain a variety of source marker information in their homolog distribution patterns that was exploited to deduce marine versus terrestrial sources, as well as regional source information.
Financial support was provided by National Science Foundation grants OCE 77-12914, OCE 81-11947, OCE 84-06666 and OCE 87-16954. We thank J. B. Alford and N. A. Hayward for assistance with the analytical work. N. M. Frew and C. G. Johnson provided the mass spectrometry. J. T. Merrill provided the long-range air mass trajectories and guided us in their interpretation. J. K. Schneider, K. Kawamura and M-A. Sicre contributed substantially to our efforts. We also thank O. C. Zafiriou for his collaboration during the early days of SEAREX. We would especially like to thank R. A. Duce for his leadership of the SEAREX program and E. Atlas for his many helpful and sometimes critical comments over the past ten years. Finally, we would like to thank all of our many SEAREX colleagues for their efforts and collaborative spirit. This is Woods Hole Oceanographic Contribution No. 6995.