Strontium isotope and trajectory method elucidating overseas migration of to Japan.

The oriental armyworm, , generally migrates from eastern to northeastern China in early summer, and some individuals are believed to migrate overseas to Japan depending on meteorological conditions. This potential migration was investigated with the immigrants' strontium radiogenic isotope ratio Sr/Sr and backward flight trajectories from Japanese trapping sites. The results showed that the Sr/Sr ratios of Chinese reared were significantly higher than those of reared insects of Japanese immigration areas.

Strontium isotope analysis of otoliths reveals differences in the habitat salinity among three sympatric stickleback species of the genus .

The analysis of otolith Sr isotope ratios (Sr/Sr) is a powerful method to study fish migration in freshwater areas. However, few studies have applied this method to study fish movement in brackish-water environments. Furthermore, despite the fact that habitat differentiation has been shown to drive genetic differentiation and reproductive isolation among stickleback fish, no studies have used the otolith Sr/Sr ratios to analyze habitat differentiation between stickleback ecotypes and species.

Microbial nitrification and acidification of lacustrine sediments deduced from the nature of a sedimentary kaolin deposit in central Japan.

Kaolin deposits in the Seto-Tono district, central Japan, were formed by intense kaolinization of lacustrine arkose sediments deposited in small and shallow inland lakes in the late Miocene. Based on mineralogical and stable isotopic (Fe, C, N) studies of Motoyama kaolin deposit in the Seto area, we concluded that it was formed by microbial nitrification and acidification of lacustrine sediments underneath an inland lake. Small amounts of Fe-Ti oxides and Fe-hydroxide in the kaolin clay indicated that iron was oxidized and leached during the kaolinization.

Major and trace elements in the surface water of Tonle Sap Lake, Mekong River, and other tributary rivers in Cambodia.

To evaluate the seasonal water circulation of Tonle Sap Lake and its tributary rivers in Cambodia, the spatial distribution patterns of major and trace elements in surface water were investigated. Based on the similarity of the dissolved elemental concentrations, the water samples were mainly divided into the three groups: samples with relatively high percentages of Ca, Mo, and Sb (Subcluster B1); samples with high Si, Al, and Fe (B2); and samples with high Na, K, and Mg (B3). During the rainy season, the elemental composition of lake water (B1) appeared to be greatly influenced by the intrusion of water from the Mekong River (B1) through the Tonle Sap River (B1).

Magnesium isotopes reveal bedrock impacts on stream organisms.

Magnesium is an essential element to aquatic organisms and understanding the origin of Mg is important for understanding their growth. Ultimately, Mg in streams is derived from the chemical weathering of bedrock in the catchment. In this study, we used Mg stable isotope ratios (δMg) to test whether stream organisms reflect lithological sources in stream catchments.

Variation of strontium stable isotope ratios and origins of strontium in Japanese vegetables and comparison with Chinese vegetables.

To evaluate the utility of Sr/Sr ratio for determining the geographical provenance of vegetables, we compared Sr/Sr ratios and Sr concentrations in five vegetable species grown in Japan and China, and we also examined the relationships between Sr/Sr ratios in vegetables, the soil-exchangeable pool, irrigation water, and fertilizer from 20 Japanese agricultural areas. The vegetable Sr/Sr ratios in Japan were similar for all species within a given agricultural area, but tended to be low in northeast Japan and high in southwest Japan. The median Sr/Sr ratio in Japanese vegetables was similar to that in fertilizer, suggesting that in addition to rock-derived Sr, vegetables contain Sr derived from fertilizers.

Characterization of a new candidate isotopic reference material for natural Pb using primary measurement method.

A lead isotopic standard solution with natural abundance has been developed by applying a mixture of a solution of enriched Pb and a solution of enriched Pb (Pb-Pb double spike solution) as bracketing method. The amount-of-substance ratio of Pb:Pb in this solution is accurately measured by applying EDTA titrimetry, which is one of the primary measurement methods, to each enriched Pb isotope solution. Also metal impurities affecting EDTA titration and minor lead isotopes contained in each enriched Pb isotope solution are quantified by ICP-SF-MS.

A simple and rapid method for isotopic analysis of nickel, copper, and zinc in seawater using chelating extraction and anion exchange.

Stable isotope ratios of nickel, copper, and zinc are powerful tools for elucidating the biogeochemical cycling of trace metals in the ocean. However, analytical difficulties have impeded isotopic studies of these metals. We present a simple and rapid method for simultaneous analysis of Ni, Cu, and Zn isotope ratios in seawater using NOBIAS Chelate-PA1 resin and anion exchange resin.

Tracing the Geographical Origin of Onions by Strontium Isotope Ratio and Strontium Content.

The strontium (Sr) isotope ratio ((87)Sr/(86)Sr) and Sr content were used to trace the geographical origin of onions from Japan and other countries, including China, the United States of America, New Zealand, Australia, and Thailand. The mean (87)Sr/(86)Sr ratio and Sr content (dry weight basis) for onions from Japan were 0.70751 and 4.