Using in-situ electrochemical sensors, we mapped the temperature, oxygen and H₂S in the diffuse flow environments of the EPR, in coordination with macrofaunal and microbial mapping done by Drs. Lutz, Shank and Vetriani. Unlike Lau Basin, partially oxidized sulfur species (polysulfides and thiosulfate), are rarely detected. Data were collected before and after the 2005-6 EPR eruptions (data were obtained for every year from 2004-8). The S/T ratio rose prior to the eruption at some sites and continued to increase after the eruption; the macrofauna changed from a mussel plus Riftia dominated community to a Tevnia dominated community. S/T ratios at EPR are typically higher than those found at Lau Basin (see white paper by Amy Gartman).

Sulfide in hydrothermal vents was measured by taking a sample and precipitating the sulfide in basic Zn-acetate solution and then frozen. The thawed sample (filtered through 200 nm filters and unfiltered were treated similarly) was treated with HCl to release sulfide from FeS (acid volatile sulfide, AVS) into a trace metal clean basic trapping solution and then sequentially treated with acidified Cr(II) to release sulfide bound to pyrite (reductive dissolution, CRS) in a separate trapping solution. The hydrothermal vents showed increasing dissolved Fe and decreasing sulfide (AVS) concentrations since the eruptions. All dissolved samples yielded significant quantities of CRS up to 11% of the total sulfide indicating that nanoparticulate pyrite is emitted from all vents studied. Similar data were found at Lau Basin vents.

Integrating our chemical data at the same site and between sites with other biological, chemical and geological data should prove useful. The papers below are examples of our first integrations of biological and chemical data.

Relevant References
Nees, H.A., T. S. Moore, K. M. Mullaugh, R. R. Holyoke, C. P. Janzen, S. Ma, E. Metzger, T. J. Waite, M. Yücel, R. A. Lutz., T. M. Shank, C. Vetriani, D. B. Nuzzio, G. W. Luther, III. 2008. Mussel habitat chemistry at 9°50’ north east Pacific Rise, pre- & post-eruption. Journal of Shellfish Research 27, 169-175.

Lutz, R. A., T. M. Shank, G. W. Luther, III, C. Vetriani, M. Tolstoy, D. B. Nuzzio, T. S. Moore, F. Waldhauser, M. Crespo-Medina, A. Chatziefthimou, E. R. Annis, and A. J. Reed. 2008. Interrelationships between vent fluid chemistry, temperature, seismic activity and biological community structure at a mussel-dominated, deep-sea hydrothermal vent along the East Pacific Rise. Journal of Shellfish Research 27, 177-190.

Crespo-Medina, M., A. D. Chatziefthimiou, N. S. Bloom, G. W. Luther III, D. D. Wright, J. R. Reinfelder, C. Vetriani, and T. Barkay. 2009. Adaptation of chemosynthetic microorganisms to elevated mercury concentrations in deep-sea hydrothermal vents. Limnology and Oceanography 54, 41-49.

Nees, H. A., R. A. Lutz, T. M. Shank and G. W. Luther, III. 2009. Pre- and post-eruption diffuse flow variability among tubeworm habitats at 9 degrees 50’ north on the East Pacific Rise. Deep Sea Research II 56, 1607-1615. doi:10.1016/j.dsr2.2009.05.007

Moore, T. S., T. M. Shank, D. B. Nuzzio and G. W. Luther, III. 2009. Time-series chemical and temperature habitat characterization of diffuse flow hydrothermal sites at 9 degrees 50' N East Pacific Rise. Deep Sea Research II 56, 1616-1621. doi:10.1016/j.dsr2.2009.05.008

Podowski, E. L., K. A. Zelnio, T. S. Moore, G. W. Luther III, and C. R. Fisher. 2009. Distribution of diffuse flow megafauna in two sites on the Eastern Lau Spreading Center, Tonga. Deep Sea Research 56, 2041-2056. doi:10.1016/j.dsr2.2009.07.002