POS, POC and PON in the Southern Ocean during the First Aerosol Characterization Experiment (ACE-1) Y Suzuki and M Taki ( Department of Biology and Geosciences, Shizuoka University, 836 Oya Shizuoka, Shizuoka 422, Japan, seysuzu@sci.shizuoka.ac.jp) T S Bates (NOAA/PMEL, 7600 Sand Point Way NE, Seattle, WA 98115, bates@pmel.noaa.gov) The organic sulfur, carbon and nitrogen content of suspended particulate was measured in the Southern and Pacific Oceans during ACE-1. POS, POC and PON concentrations in suspended matter within the upper 150m ranged from 0 (n.d.) to 67.8 nM S, 0.11 to 9.13 uM C and 0.01 to 1.14 uM N. The vertical profiles of POS, POC and PON were very similar with a surface maximum at most stations and a subsurface maximum at a few locations. The POS concentrations were greater in the Southern Ocean than in the Pacific Ocean. The average molar C:N:S ratios were 320:39:1 although the ratios measured covered a very wide range (C/S and N/S ratios in the Southern Ocean waters ranged from 31 to 654 and 2 to 73, respectively). It appears that time scales of C, N and S cycling are quite different in this region. These measurements were made aboard the R/V Discoverer. The measurements were made a periodic intervals between 5-150m depth. Each set of mesurements is identified by a 5-digit cast number. The first digit refers to the leg of the cruise (1 or 2), the next 3 digits refer to the station number, and the last digit is the cast number at that station. For example 10121 would be leg 1, station number 12, cast 1. To see other data gathered during these soundings refer to the dataset entitled ACE-1 Discoverer CTD Cast Data (Johnson)