Sequential extraction integrated with isotope analysis was carried out on a sediment core from Liaodong Bay, northeast China, for characterizing Pb in various extraction phases and its possible sources. Results show that in all extracted fractions Pb concentrations increased abruptly in the top part of the sediments that deposited after 1980, but remained lower and rather constant before 1980. ...

The pattern of resource partitioning vs depth by corals collected in February 1983 from Jamaica and the Red Sea was determined from their stable carbon isotope composition. Observations were made on isolated zooxanthellae and corresponding algae-free animal tissue from eight species at four depths over a 50 m bathymetric range. Zooxanthellae 6~3C was high in shallow water and became lower as de...

Geologic intervals of sustained warmth such as the mid-Pliocene Warm Period can inform our understanding future climate change, including long-term consequences oceanic uptake anthropogenic carbon. Here we generate carbon isotope records and synthesize existing to reconstruct position water masses determine circulation patterns in deep Pacific Ocean. We show that mid-depth gradient North was re...

Meyers, P.A., 1992. Changes in organic carbon stable isotope ratios across the K/T boundary: global or local control? In: S.A. Macko and M.H. Engel (Guest-Editors), Isotope Fractionations in Organic Matter: Biosynthetic and Diagenetic Processes. Chem. Geol. (Isot. Geosci. Sect. ), l 01: 283-29 I. A global shift in carbonate carbon j~3C-values from heavier values in the Maastrichtian to lighter ...

Nitrogen (N) isotope ratios ((15)N/(14)N) provide integrative constraints on the N inventory of the modern ocean. Anaerobic ammonium oxidation (anammox), which converts ammonium and nitrite to dinitrogen gas (N2) and nitrate, is an important fixed N sink in marine ecosystems. We studied the so far unknown N isotope effects of anammox in batch culture experiments. Anammox preferentially removes ...

High-resolution stable isotope profiles of three contemporaneously deposited stalagmites from a shallow cave in Southern Oman provide an annually resolved record of Indian Ocean monsoon rainfall variability for the past 780 years. Uranium-series age dating and counts of annual growth bands enable an excellent age calibration. Although modern speleothems do not grow in perfect isotopic equilibri...

Large-scale patterns of isotope ratios are detectable in the tissues of organisms, but the variability in these patterns often obscures detection of environmental trends. We show that plants and animals at lower trophic levels are relatively poor indicators of the temporal trend in atmospheric carbon isotope ratios (delta13C) when compared with animals at higher trophic levels. First, we tested...

Isotope analysis is a potentially sensitive method to trace in situ degradation of organic contaminants. In a recent paper, Morasch et al. (3) investigated the mechanism of isotope fractionation during toluene biodegradation using deuteriumlabeled toluene. The authors overlooked that the Rayleigh equation that is normally used to evaluate isotope fractionation at natural abundance level (2) is ...