Stable Carbon and Nitrogen Isotopic Compositions of SelectedOrganic Compounds

将测量大量有机质、类脂和选定的色素(叶绿素a、b和c；B-胡萝卜烯；以及褐色素)的稳定碳和氮同位素组成，以调查选定海洋环境中有机质的来源和循环。将使用制备规模的高效液相色谱方法分离出足够数量的纯母体色素，以进行精确和准确的稳定同位素分析。碳和氮的吸收和生物合成利用导致了特征动力学分馏，可用来定义特定有机库的“生命史”。虽然整体有机质性质的测定是有用的，但特定标记化合物的稳定同位素分析对于解卷解由多个来源和复杂过程产生的有机基质具有很大的前景。实地研究将包括描述三种明确的海洋环境，以评价特定于色素的稳定同位素分布的可变性、实用性和局限性，以(1)分解陆地和海洋生物量；(2)区分沉积物中的有机物质来源；(3)确定上层水柱中“新的”生产与“循环”生产的相对重要性。//

Stable carbon and nitrogen isotope compositions of bulk organic matter, lipids and selected pigments (chlorophylls a, b and c; B-cartene; and phaeopigments) will be measured to investigate the sources and cycling of organic matter in slected marine environments. Preparative-scale high-performance liquid chromatographic methods will be used to isolate sufficient quantities of pure parent pigments for precise and accurate stable isotope analysis. Carbon and nitrogen uptake and biosynthetic utilization cause characteristic kinetic fractionations that can be used to define the "life histories" of of specific organic pools. While determinations of bulk organic matter properties are useful, the stable isotopic analysis of specific marker compounds holds great promise for deconvoluting organic matrices produced by multiple sources and complex processes. Field studies will include the characterization of three well- defined oceanographic settings to evaluate the variability, utility and limitations of pigment-specific stable isotope distributions for (1) resolving terrestrial and marine biomass; (2) differentiating organic matter sources in sediments; and (3) determining the relative importance of "new" vs. "recycled" production in the upper water column. //