Revised delta(34)S reference values with associated expanded uncertainties (95% confidence interval (C.I.)) are presented for the sulfur isotope reference materials IAEA-S-2 (22.62 +/- 0.16 per thousand) and IAEA-S-3 (-32.49 +/- 0.16 per thousand). These revised values are determined using two relative-difference measurement techniques, gas source isotope ratio mass spectrometry (GIRMS) and dou...

it is very important to determine the stable nitrogen isotope ratio for the nitrogenous substances in aerosols and the geochemistry behavior of stable nitrate ion isotopes in aerosols in order to elucidate the chemical and physical functions of clouds. hence, aerosol field sampling was conducted in the skies offshore from malibu beach and santa barbara, california, u.s.a. on 16 and 18 july 2009...

To assess the influence of stream water on leaf gas exchange and water potential in different sized boxelder trees (Acer negundo L.), we compared these characteristics in trees growing beside a perennial stream and a nearby ephemeral stream in a montane-riparian forest in northern Arizona. Patterns of tree water use were quantified by stable isotope analysis (delta(18)O). Physiological characte...

Elemental carbon and nitrogen levels and isotope ratios were assessed in different biological compartments of a Northwest (NW) Mediterranean bay to trace the various sources of nutrient input from natural (river runoffs) and anthropogenic (harbor outflows, fish farms and urban sewage outfall) sources. Samples from transplanted mussels and natural sea grass communities (Posidonia oceanica leaves...

†Background and Aims One of the most striking attributes of clonal plants is their capacity for physiological integration, which enables movement of essential resources between connected ramets. This study investigated the capacity of physiological integration to buffer differences in resource availability experienced by ramets of the clonal wild strawberry plant, Fragaria vesca. Specifically, ...

Photosynthetic carbon assimilation and transpirational water loss play an important role in the yield and the carbon sequestration potential of bioenergy-devoted cultures of fast-growing trees. For six poplar (Populus) genotypes in a short-rotation plantation, we observed significant seasonal and genotypic variation in photosynthetic parameters, intrinsic water-use efficiency (WUEi) and leaf st...

Watershed-scale carbon budgets remain poorly understood, in part due to inadequate simulation tools to assess in-stream carbon fate and transport. A new numerical model termed ISOtope-based FLuvial Organic Carbon (ISOFLOC) is formulated to simulate the fluvial organic carbon budget in watersheds where hydrologic, sediment transport, and biogeochemical processes are coupled to control benthic an...

To quantify the contribution of autotrophic microorganisms to organic matter (OM) formation in soils, we investigated natural CO2 vents (mofettes) situated in a wetland in northwest Bohemia (Czech Republic). Mofette soils had higher soil organic matter (SOM) concentrations than reference soils due to restricted decomposition under high CO2 levels. We used radiocarbon (1 C) and stable carbon (δC...

Ultraviolet laser microprobe analyses of a calcium-aluminum-rich inclusion (CAI) from the Allende meteorite suggest that a line with a slope of exactly 1.00 on a plot of delta (17)O against delta (18)O represents the primitive oxygen isotope reservoir of the early solar nebula. Most meteorites are enriched in (17)O and (18)O relative to this line, and their oxygen isotope ratios can be explaine...