HR: 1330h
AN: B12A-0761    [PDF]
TI: Dissolved Organic Metals in the Hydrothermal Plume
AU: * Shitashima, K
EM: shita@criepi.denken.or.jp
AF: Central Research Institute of Electric Power Industry, 1646, Abiko, Abiko, Chiba, 2701194 Japan
AB: In the hydrothermal plume, there are the unique microbiological communities and the microorganism utilizes various chemical substances. The interactions between heavy metals and microorganisms in the hydrothermal plume are important to comprehend the oceanic geochemical cycles of heavy metals. It is considered that the heavy metals in hydrothermal plume are organically bound with dissolved organic matter derived from the hydrothermal microorganism. This study funded by the O`Archaean ParkO_L project of MEXT is a first attempt to observe the bioavailability of heavy metals in hydrothermal plume. The hydrothermal plume samples were taken from two different kinds of hydrothermal sites, the Suiyo Seamount caldera and the Central Indian Ridge. The mini CTDT-RMS mounted twelve 1.2L Niskin bottles was installed on the manned submersible, and the hydrothermal plume samples were collected by taking the distance from the hydrothermal vents gradually. The solid phase extraction technique in C18 Sep-Pak cartridge (Millipore Waters) was used to extract the dissolved organic matter from the hydrothermal plume samples. Dissolved heavy metals (Al, Mn, Fe, Cu, Zn, Co, Ni, As, Mo, Cd and Pb) bound with C18 Sep-Pak extractable organic matter, dissolved organic metals, were analyzed by GFAAS. In all measured heavy metals, the dissolved organic metals existed in the hydrothermal plume samples collected from two sites. The concentration of the dissolved organic metals ranged from 0.5nM to 30nM and was about 1/1000~1/100 of the total dissolved heavy metals concentration. It suggests that these heavy metals were bound with organic matter originated in the hydrothermal microorganism. Though the abundance of the organism in the Central Indian Ridge is larger than that in the Suiyo Seamount caldera, the concentration of the dissolved organic metals in the plume samples at the Suiyo Seamount caldera was higher than that at the Central Indian Ridge. These results indicate that the bioavailability of heavy metals is different in two sites.
DE: 1030 Geochemical cycles (0330)
DE: 4803 Bacteria
DE: 4807 Chemical speciation and complexation
DE: 4825 Geochemistry
DE: 4875 Trace elements
SC: Biogeosciences [B]
MN: 2003 Fall Meeting