The Application Of Stable Carbon And Nitrogen Isotopes To Ecosystems--Such As The Wudinghe River And The Yellow Sea And East China Sea

Three sections are introduced in this paper. First, the analysis methods of stable carbon and nitrogen isotopes methods used in the laboratory of FIO are described and the precision and accuracy of the methods are validated. Two amino acid derivatization methods are compared, which is a staged study on measurements of stable isotope compositions of individual amino acids. Second, the stable carbon and nitrogen isotope methods are used in the Wudinghe river ecosystem. The stable isotope compositions of plants, soils and sediments in the Wudinghe drainage area are investigated. Based on this, the sources of the suspended matter from the Wudinghe drainage area and the relationship between the sources and the eroding function and vegetations in this area are discussed. Third, the stable carbon and nitrogen isotope methods are used in the Yellow Sea and East China Sea ecosystem. The stable carbon and nitrogen isotopes from primary production to the toppest predator are detected. The trophic levels of in situ organisms are calculated and the results are compared with that of the traditional gut-contents analysis.Measurements of the working standards for stable carbon isotopes (FIO spectrum carbon) and for stable nitrogen isotopes (DL-a-alanine) show that the precisions of measurement of stable carbon and nitrogen isotopes in the laboratory are high. The stable carbon isotope measure can reach ?.08 %o, and the stable nitrogen isotope measure can reach ?.07 %o. Through comparison with an international standard NBS-19 and a national recommendatory standard TTB-1, the results show that the MAT-251 mass spectrometer has higher accuracy when it measures stable carbon isotopes.The study of stable isotope composition in organic molecule compounds, especially in individual amino acids of organism by the mean of GC/C/IRMS can helpus understand the metabolism more clearly. The Derivatization procedure is a key step in determining the stable carbon isotope compositions of individual amino acids by gas chromatography - combustion - isotope ratio mass spectrometry (GC/C/ERMS). Seventeen amino acid standards are derivatizated by two methods: one is N-acetyl propyl amino acid esters (NAP) method; the other is N-trifluoroacetyl isopropyl amino acid esters (TFAIP) method. The reproducibility and the isotopic fractionation of these two derivatization methods have been compared by measuring the stable carbon isotope compositions of individual amino acid standards and their derivatizates. The results have proved that the reproducibility of amino acid N-TFA isopropyl amino acid ester method is better than that of N-acetyl propyl amino acid esters (NAP) method. The isotopic fractionation of TFAIP method is much lower than that of NAP method. TFAIP method is a better derivatization method.Biogenic elements (mainly carbon, nitrogen, etc) and various pollutants in rivers undergo very complex environmental biogeochemical processes, such as transportation, transformation, etc, causing different ecological effects. It has an important scientific and practical significance that to open out their environmental behavior and to elucidate their distribution feature on a district scale. Anj;-investigation of carbon and nitrogen isotope compositions in the Wudinghe drainage area, which is a high turbid distributary in the middle reach of the Yellow River, has been conducted. It is found that the values of carbon and nitrogen stable isotopes of plants in the basin have wide ranges, the carbon isotope values show a character of double peaks, but nitrogen isotopes have no relativity to carbon ones. A weak negative relativity exists between carbon and nitrogen stable isotopes in sediments along the river. Carbon and nitrogen stable isotope values in the suspended matter exhibit a good negative relationship, reflecting the two main sources of suspended matter in this river and conservative feature of physical mixture. Based on the investigation of carbon stable isotopes of plants, soils and sediments from the Wudinghe drainage area the contributio...