Air-side flux measurements UCI API CIMS (Proton transfer atmospheric pressure ionization) DMS, acetone (10 Hz) Sensitivity ~100 Hz/ppt DMS Currently being downsized (from the “bigCIMS” to the “mesoCIMS”) Requirements: 0.5m 3 +rack, short tubing run to bow, winds/motion, lab quality power and A/C

Continuous seawater measurements for air/sea gradient UCI API CIMS (Proton transfer atmospheric pressure ionization) Low cost, low sensitivity (“miniCIMS”) TFE membrane equilibrator Sensitivity: <0.1nM DMS at 1 minute averaging time, pM acetone Requirements: seawater supply (bow pump, fish), lab space, sink

k DMS vs U for low-moderate wind speeds (Marandino et al. 2009)

Anomalous DMS gas transfer in N. Atlantic coccolith bloom (Marandino et al. 2009)

References: Blomquist, B., et al. (2006), Geophys. Res. Lett., 33, doi: /206GL Fairall, C., et al. (1996), J. Geophys. Res.-Oceans, 101, Ho, D., et al. (2006), Geophys. Res. Lett., 33, doi: /2006GL Huebert, B., et al. (2004), Geophys. Res. Lett., 31, doi: /2004 GL McGillis, W., et al. (2004), J. Geophys. Res.- Oceans, 109, doi: /2003J G McGillis, W., et al. (2001a), J. Geophys. Res.- Oceans, 106, McGillis, W., et al. (2001b), Mar. Chem., 75, 267. Miller, S., et al. (in press), Geophys. Res. Lett.. Nightingale, P., et al. (2000a), Geophys. Res. Lett., 27, Nightingale, P., et al. (200b), Global Biogeochem. Cycles, 14, 373. Wanninkhof, R., et al. (2004), J. Geophys. Res.- Oceans, 109, doi: /2003J C Wanninkhof, R., et al. (1997), Geophys. Res. Lett. 24, Wanninkhof, R., et al. (1993), J. Geophys. Res.- Oceans, 98, Wanninkhof, R. (1992), J. Geophys. Res., 97, Christa A. Marandino 1*, Warren J. De Bruyn 2, Scott D. Miller 3, Eric S. Saltzman 1 1 University of California, Irvine, Irvine, CA, 2 Chapman University, Orange, CA 3 Atmospheric Sciences Research Center, State University of New York, Albany, Albany, NY *now at IFM-GEOMAR, Kiel, Germany Air/sea gas transfer coefficients: A multi-study synthesis Introduction: Eddy correlation (EC) flux measurements in 3 ocean basins: PHASE I - N. and Eq. Pacific, May-July, 2004 Knorr_06 (K06) - S. Pacific, January, 2006 Knorr_07 (K07) – N. Atlantic, July, 2007 DMS air/sea flux (F) and concentrations (ΔC) measured continuously using atmospheric pressure chemical ionization mass spectrometer (API-CIMS) and Campbell C-SAT 3 sonic anemometer DMS seawater levels continuously measured at 5 m depth using a membrane equilibrator Gas transfer coefficient (k) computed using k=F/ ΔC The wind speed dependence of k examined and compared to that of other DMS studies, as well as CO 2 and dual tracer studies Abstract OS31B-1261 DMS and Dual Tracers: C o m p ar is o n of D M S wi th d u al tr ac er st u di es: SAGE (Ho et al., 2006) Georges Bank (Wanninkhof et al., 1993) GASEX (McGillis et al., 2001b) N. Sea (Nightingale et al., 2000b) FSLE (Wanninkhof et al., 1997) SOFEX (Wanninkhof et al., 2004) IRONEX (Nightingale et al., 2000a) DMS Studies Comparison of 5 published DMS EC studies: PHASE I K06 K07 H04 (Huebert et al., 2004) BIO (Blomquist et al., 2006) Similar results across all cruises Big Questions Remain What factors control the wind speed dependence of k? Is k vs. U relationship the same for all trace gases? Can k values always be determined from 5 m depth Cw values? What about high winds Do blooms alter k for some or all trace gases? EC sampling setup for K07 DMS and CO 2 on ship mast DMS and CO 2 compare to CO 2 direct flux studies with derived k values: GASEX-98 (McGillis et al., 2001a) GASEX-01 (McGillis et al., 2004) Knorr_07 (K07, Miller et al., subm.) DMS more linear than GASEX-98 Steeper k vs U than GASEX-01 at low wind speed despite similar oceanographic conditions Acknowledgements: Thanks to Oregon St. & WHOI ship op staff and the captain and crew of the R/V Knorr, Cyril McCormick, the Saltzman lab past and present. Funding provided by the NSF Atmospheric Chemistry Program. This is a contribution to the U.S. Solas Project. Linear regression, 95% confidence intervals: k = 0.55U – 0.55 r 2 = nd order polynomial regression, 95% confidence intervals: k = 0.04U U+0.68 r 2 = 0.81 k values derived from N. Atlantic EC measurements: pink points inside summer coccolith bloom, black points outside bloom k values inside bloom up to 5x higher than outside Implications – evidence of near surface DMS gradients? N. Atlantic DMS fluxes greater than previous estimates? DMS contribution to sulfate aerosol loading larger than predicted? Similar k vs U for DMS and dual tracers Implications - 1) over this U range, DMS transfer due to same physics as inert gases, 2) no evidence of interfacial DMS chemical/biological production/loss. DMS more similar to K07 CO2 K07 CO2 measured concurrently w/ K07 DMS All exhibit less dependence on U than GASEX-98 and more than GASEX-01