Foraging ecology of five toothed whale species in the Northwest Iberian Peninsula, inferred using carbon and nitrogen isotope ratios

Stable isotope ratios of bone collagen have been used to determine trophic levels in diverse archaeological populations. The longest established and arguably most successful isotope system has been nitrogen, followed by carbon, and more recently hydrogen. These trophic level proxies rely on a predictable change in isotope ratio with each trophic level step; however, this requirement may not always be met, which can lead to difficulties in interpreting archaeological evidence. In agricultural communities, in particular, there are several possible complications to the interpretation of nitrogen and carbon isotopes. Recent approaches to overcome these limitations include better quantification and understanding of the influences on consumer isotope ratios; inclusion of evidence from plant remains; further investigation of apatite δ13C—collagen δ13C spacing in bones; measurement of carbon and nitrogen isotope ratios in individual amino acids, rather than collagen; and development of other stable isotope proxies for trophic level, such as hydrogen isotopes.

Download Full-text

Changes of Isotopic Composition in Gases Emitted from Wastewater Treatment Plant - Preliminary Study

Ecological Chemistry and Engineering S ◽

10.2478/eces-2014-0019 ◽

2014 ◽

Vol 21 (2) ◽

pp. 245-254

Author(s):

Wioleta Stelmach ◽

Paweł Szarlip ◽

Andrzej Trembaczowski

Keyword(s):

Wastewater Treatment ◽

Wastewater Treatment Plant ◽

Municipal Wastewater ◽

Treatment Process ◽

Treatment Plant ◽

Nitrogen Isotope ◽

Isotope Ratios ◽

Biogenic Element ◽

Municipal Wastewater Treatment ◽

Carbon And Nitrogen

Abstract Investigations of processes occurring during wastewater treatment have progressed beyond the stage of technology. Currently, great numbers of representatives of diverse specialist research apply increasingly sophisticated measurement methods that have not been employed in this field of science. One of the methods is IRMS (Isotope Ratio Mass Spectrometry). Tracking changes in the ratios of biogenic element isotopes is useful in eg identification and monitoring of investigated processes. Since the IRMS technique has hardly been used for investigations of the wastewater treatment process, pilot research should be instigated to determine the isotope ratios occurring naturally in the process. The aim of the study was to determine changes in carbon and nitrogen isotope ratios at the successive stages of the technological line in wastewater treatment plants. The study material comprised: i) suspensions of raw sewage and mixtures of wastewater and activated sludge; ii) gases sampled from the volume of the suspensions; iii) gases sampled from the air above the suspension surface. The research material originated from the facilities of “Hajdow” municipal wastewater treatment plant in Lublin (SE Poland). The samples were analysed for the carbon and nitrogen isotope ratios, and the concentrations of the gases as well as total organic carbon (TOC), inorganic carbon (IC), Kjeldahl nitrogen (KN), dry weight, pH, and Eh were determined. The results obtained suggest that: i) the IRMS technique can be successfully applied in investigations of processes occurring during wastewater treatment; ii) isotope ratios in the carbon and nitrogen compounds (CO2 and N2) both in the suspensions and gases contained therein and in the air above them differ from each other and change at the different stages of the treatment process; iii) further research is indispensable in order to identify processes responsible for fractionation of carbon and nitrogen isotopes.

Download Full-text