HR: 0800h
AN: V41B-1393    [Abstracts]
TI: Characterization of Dissolved Organic Matter from Deep-sea Floor Hydrothermal Vents in South Mariana Backarc Spreading Center
AU: * Kitajima, F
EM: kitajima@geo.kyushu-u.ac.jp
AF: Kyushu University, Dept. of Earth and Planetary Sciences, 6-10-1, Hakozaki, Higashi-ku, Fukuoka,, 812-8581 Japan
AU: Yamanaka, T
EM: tyama@rc.kyushu-u.ac.jp
AF: Kyushu University, Graduate School of Social and Cultural Studies, 4-2-1, Ropponmatsu, Chuo-ku, Fukuoka,, 810-8560 Japan
AB: In South Mariana Backarc Spreading Center, a few active hydrothermal fields are located. We investigated a characterization of dissolved organic matter (DOM) from hydrothermal vents in this area, in order to clarify the biosphere beneath deep-sea floor. Hot water sample was collected from a drilled hole (APM01 located in Fryer site, 12$^{o}$ 55.22$^{_f}$N, 143$^{o}$ 37.16$^{_f}$E, depth 2850m) during the ROPOS/TN167A cruise in March 2004. The hole had been drilled during Hakurei-Maru 2 cruise in January 2004. Another hot water sample was collected from a natural black smoker located in Pika site (12$^{o}$ 55.15$^{_f}$N, 143$^{o}$ 36.96$^{_f}$E, depth 2773m) during YK03-09 cruise. In this investigation, we developed a standalone filtration system in order to collect and enrich dissolved organic matter of quite low concentration. This system was designed to be put near hydrothermal vents for at least 24h. This system has an ODS disk (Empore$^{TM}$ High Performance Extraction Disk C18 90mm\phi\) with a pre-filter (Whatman GMF 1 \mu\)m filter paper) to adsorb dilute organics. We collected DOM from the APM01 casing pipe for about 30h (Tmax = 25-30 $^{o}$ C, the estimated volume of filtrated water is max. 300L) using this filtration system. Adsorbed organics were eluted with methanol for 12h twice and toluene once using soxhlet extractor. Recovered amounts of methanol eluents are 72.8mg for APM01, and 89.7mg for the black smoker. Prior to GCMS analysis, we carried out high resolution $^{1}$ H-NMR measurement (400MHz), together with the DOM samples collected from the Suiyo Seamount in July-August 2001 and August 2002. Most of the samples show signals in the region of 3-4 ppm, and the samples from the vents of relatively low temperatures (APM01 and AP04: the natural vent at the Suiyo Seamount, temperature 8-48$^{o}$ C ) show signals also in the region of 0.8-1.6 ppm.
DE: 8424 Hydrothermal systems (8135)
DE: 9355 Pacific Ocean
DE: 4832 Hydrothermal systems
DE: 1055 Organic geochemistry
DE: 0400 Biogeosciences
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting