[1] Nitrate (NO3 ) concentrations and dual isotopic composition (dN and dO) were measured during various seasons and tidal conditions in Elkhorn Slough to evaluate mixing of sources of NO3 within this California estuary. We found the isotopic composition of NO3 was influenced most heavily by mixing of two primary sources with unique isotopic signatures, a marine (Monterey Bay) and terrestrial a...

Koehler, G.D., Chipley, D. and Kyser, T.K., 1991. Measurement of the hydrogen and oxygen isotopic compositions of concentrated chloride brines and brines from fluid inclusions in halite. Chem. Geol. (Isot. Geosci. Sect.), 94: 45-54. Solutions of l-5 m NaCI, KCl, CaC12 and MgC12, and synthetic brines were analyzed for hydrogen and oxygen isotopic compositions by vacuum distillation-microequilibr...

We present the isotopic composition of meltwater samples from four seasonal snowpacks: a warm, maritime snowpack in California; a temperate continental snowpack in Vermont; a cold continental snowpack in Colorado; and an Arctic snowpack in Alaska. Despite the very different climate conditions the υ18O of meltwater from all four snowpacks increased as melting progressed. This trend is consistent...

*Correspondence: Der-Chuen Lee, Institute of Earth Sciences, Academia Sinica, 128, Sec. 2, Academia Rd., Nankang, Taipei 115, Taiwan e-mail: [email protected] The dissolved concentration and isotopic compositions of cadmium (Cd) in the seawater of the West Philippine Sea (WPS) were determined. In general, Cd isotopic composition in the water column decreased with depth, with 114/110 11 ...

The isotope ratios of Sr are useful tracers for studying parent material sources, weathering processes, and biogeochemical cycling. Mineralogical and geochemical investigations of two lateritic weathering covers, in an area close to the Tropic of Cancer (Guangxi Province, southern China), were undertaken to study the regional weathering processes and Sr isotopic sources. We found that weatherin...

The concentration and isotopic composition of monochlorobenzene (MCB) was monitored in the plume of an anaerobic, contaminated aquifer in Bitterfeld, Germany. An enrichment in the carbon isotopic composition of more than 4 delta units was found at the fringes of the plume relative to the center (-26.5 %), suggesting the occurrence of in situ biodegradation of MCB. A similar enrichment was measu...

The difference in isotopic composition between a consumer's tissues and that of its diet is a critical aspect of the use of stable isotope analyses in ecological and palaeoecological studies. In a controlled feeding experiment with the Atlantic salmon, Salmo salar, we demonstrate for the first time that the value of tissue-diet isotope spacing in nitrogen in a growing animal is not constant, bu...

The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour iso...

We report concentrations and isotopic compositions of He, Ne, and Ar measured with high spatial resolution along a radial traverse of a silicon carbide (SiC) quadrant of the Genesis mission concentrator target. The Ne isotopic composition maps instrumental fractionation as a function of radial position in the target: the maximum observed isotopic fractionation is approximately 33& per mass unit...