Tetsuya Torii

Unusual distributions of long-chain n-alkanes and n-alkenes in antarctic soil.

Abstract Hydrocarbons in soil samples from the McMurdo Dry Valleys of southern Victoria Land, Antarctica, were studied to examine their features and to elucidate source materials. Normal-alkanes and n -alkenes were found at concentrations ranging from 13 to 2200 and from 1.1 to 5000 ng/g of dry soil, respectively. Unexpectedly, the major hydrocarbons were all odd-carbon numbered long-chain n -alkanes with maximum concentrations n -C 23 , n C 25 or n -C 27 . This may be due to the erosion of sedimentary materials containing vascular plant debris formed during the pre- and inter-glaciation periods of Antarctica (Miocene-Pliocene) and microbial debris, such as fungi and microalgae. Normal-alkenes maximize at n -C 23:1 (carbon chain length: number of double bonds), n -C 25:1 , n -C 27:1 or n -C 29:2 , which could be derived from cyanobacteria and microalgae, that lived in the past in the Antarctic cold desert and/or organic debris of wind-transported cyanobacterial mats.

The origin of salts in water bodies of the McMurdo Dry Valleys

Lithium distributions in lake and pond waters of the McMurdo Dry Valleys of southern Victoria Land, Antarctica were studied to elucidate the origin of dissolved salts and the evolutionary history of the lakes and ponds. The Ef Li [(Li/Cl)sample/(Li/Cl)seawater] values of the bottom waters in Lakes Bonney and Fryxell were higher than unity (Ef Li =4–7), indicating that the salts originated from sea salts (probably relict seawater) and have been subsequently modified by the contribution of meltwaters containing atmospheric fallout and/or rock and soil weathering products. In contrast, extremely high Li concentrations with high Ef Li values in the Don Juan Pond water (Ef Li = 180) and the bottom waters of Lake Vanda (Ef Li = 40) suggest that the salts originated from deep groundwaters influenced mainly by saline water-rock interactions, as supported by the dissolution experiments of granite in NaCl solution. The low Li concentrations of pond waters with high Ef Li values in the Labyrinth indicate that the salts are derived from atmospheric fallout. The decrease of the Ef Li values with the increase of Cl concentrations can be explained by the repeated cycles of the migration of Li into the ice phase and subsequent ablation of surface ice, as indicated by seawater freezing experiments.

Biogeochemical investigation in serpentine-chromite ore district

Abstract Chemical analyses were made of stream and underground waters, soils and vegetation from a serpentine-chromite ore district. The distribution of several elements in plant and soil was examined statistically and soil-plant relationships were discussed. Of eighteen species of plant examined, Clethra and Castanea showed great accumulation of cobalt and manganese, respectively. Lognormal distribution was assumed in plant for several elements.