نتایج جستجو برای: δ13c
تعداد نتایج: 1653 فیلتر نتایج به سال:
Spatial changes in the dietary regime of Ruditapes philippinarum from intertidal sediments of Arcachon Bay were depicted by analyzing stable isotope ratios in both its adductor muscles and potential trophic sources. Manila clams were collected from 50 sites in May to June 2006. Dietary reconstruction was based on the IsoSource mixing model, considering trophic enrichments of 3.5‰ for carbon and...
Laboratory experiments with the planktonic foraminifera Globigerina bulloides (nonsymbiotic) and Orbulina universa (symbiotic) were carried out to examine the effects of temperature, irradiance (symbiont photosynthesis), [CO 3 ], and ontogeny on shell δ13C values. In ambient seawater ([CO 3 ] D 171 μmol kg 1), the δ13C of G. bulloides shells decreases 0.11‰ oC , a pattern that likely results fr...
Whether photosynthetic pathway differences exist in the amplitude of nighttime variations in the carbon isotope composition of leaf dark-respired CO2 (δ13Cl) and respiratory apparent isotope fractionation relative to biomass (ΔR,biomass) in response to drought stress is unclear. These differences, if present, would be important for the partitioning of C3-C4 mixed ecosystem C fluxes. We measured...
We used stable carbon (δ13C) and nitrogen (δ15N) isotope analysis to investigate the trophic ecology of 8 small cetacean species of the southwestern South Atlantic Ocean: 6 delphinids (Grampus griseus, Lagenorhynchus cruciger, L. australis, Lissodelphis peronii, Pseudorca crassidens, and Cephalorhynchus commersonii ) and 2 phocoenids (Phocoena dioptrica and P. spinipinnis). We also analyzed sam...
Hooves preserve the isotopic information laid down during their growth and may be used for reconstruction of animal feeding history. To assign certain positions along hooves to corresponding times, growth rates are required. Hoof growth rates are known for domestic animals; however, they cannot be obtained easily in wild animals. We estimated the hoof growth rate of the European roe deer (Capre...
To understand the morphological and physiological responses of leaves to changes in altitudinal gradients, we examined ten morphological and physiological characteristics in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated t...
Life-time records of the trophic sources of carbon, nitrogen and of growth rate can be generated from biogenic structures that show accretionary growth, including fish scales, whale baleen and the teeth of some animals. Records generated from individual teeth can also be combined to provide longer time series elucidating changes in environmental conditions encountered by a population. Both intr...
δCO2 measured in Antarctic ice cores provides constraints on oceanic and terrestrial carbon cycle processes linked with millennial-scale changes in atmospheric CO2. However, the interpretation of δCO2 is not straightforward. Using carbon isotope-enabled versions of the LOVECLIM and Bern3D models, we perform a set of sensitivity experiments in which the formation rates of North Atlantic Deep Wat...
We provide a comprehensive review of the proxy data on the 13C / 12C ratios and uncertainties of emissions of reactive carbonaceous compounds into the atmosphere, with a focus on CO sources. Based on an evaluated set-up of the EMAC model, we derive the isotope-resolved data set of its emission inventory for the 1997–2005 period. Additionally, we revisit the calculus required for the correct der...
Appropriateness of the inorganic Δ47-temperature calibration for brachiopods and molluscs Ghosh et al. (2006) 1 determined the relationship between Δ47 and temperature (Eq 4) by analyzing the CO2 extracted from synthetic calcites grown in the laboratory at known, controlled temperatures. In addition, they analyzed natural surface-dwelling corals (Porites) and deep-sea corals (D. dianthus), whic...
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