Community structure and functioning is shaped by resource partitioning between cooccurring species. Niche differentiation among sympatric species can be reached through trophic, spatial or temporal segregation to avoid competitive exclusion. Intraspecific segregation in the use of habitats and resources might determine, in turn, a population’s niche width and interspecific segregation. The Albo...

Observations of atmospheric CO2 mole fraction and the 13C / 12C ratio (expressed as δ13C) in urban airsheds provide constraints on the roles of anthropogenic and natural sources and sinks in local and regional carbon cycles. In this study, we report observations of these quantities in Nanjing at hourly intervals from March 2013 to August 2015, using a laser-based optical instrument. Nanjing is ...

The stable carbon isotope composition of dissolved inorganic carbon (δ13C-DIC) can be used to quantify fluxes within the carbon system. For example, knowing the δ13C signature of the inorganic carbon pool can help in describing the amount of anthropogenic carbon in the water column. The measurements can also be used for evaluating modeled carbon fluxes, for making basin-wide estimates of anthro...

Origins of atmospheric polycyclic aromatic hydrocarbons (PAHs) in total suspended particulate (TSP) and particulate matter below 10 micrometers in diameter (PM10) collected in the urban areas of Urumchi and Zhengzhou, China, are discussed on the basis of carbon isotopic compositions of individual compounds. Carbon isotope ratios were measured with the system of GC-C-IRMS with an error (1σ) of l...

Organochlorine contaminants (OCs) and stable isotopes of carbon (δ13C) and nitrogen (δ15N) were determined in 7 benthic and 7 pelagic marine invertebrate species from the North American Arctic to identify factors influencing OC concentrations. Values of δ13C separated benthic (enriched in 13C) from pelagic species and δ15N values gave a logical approximation of trophic level (TL). With few exce...

Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC i...

Multiple stable isotope and fatty acid analyses were applied to examine food web dynamics in an eelgrass Zostera marina L. system in the western Baltic Sea. Samples of eelgrass, epiphytic algae, sand microflora, red algae, phytoplankton and main consumer species were collected in June 2002. δ13C values of primary producers ranged from –9.6‰ for eelgrass to the most depleted value of –34.9‰ for ...

Sections from cattle hair serve as an isotopic archive-they contain information on the cattle diet from different time periods. We tested the reliability of 13C signatures (δ13C) in cattle tail switch hair to retrospectively trace back the annual dietary proportion of maize of different production systems without having to sample and analyze the feed. Furthermore, we investigated if differences...

The isotopic composition of methyl bromide (CH3Br) has been suggested to be a potentially useful tracer for constraining the global CH3Br budget. In order to determine the carbon isotopic composition of CH3Br emitted from the most significant anthropogenic application (pre-plant fumigation) we directly measured the δ13C of CH3Br released during commercial fumigation. We also measured the isotop...