Controls on the Isotopic Compositions of Individual Compoundin Photosynthethetic Autotrophs

这项建议的目的是调查环境变量对浮游植物中主要成分生物化学物质的同位素组成的重要性。具体地说，目的是更好地了解营养限制和光照限制如何影响光合作用自养生物中单个有机化合物的分布和同位素组成。这项研究将评估营养限制和主要藻类生物标志物的代表性物种的影响。为了实现这一目标，主要藻类的代表物种(硅藻、裸藻、蓝藻和浮游藻目)将在各种条件下生活在恒温生长室中，其同位素是确定浮游动物放牧对脂类和色素结构和同位素组成的影响。这将通过允许浮游植物饲料从一个恒化器生长室在受控条件下流入含有浮游动物的第二个室来实现。藻类的生化组成将与浮游动物的组成进行比较，以研究微生物链相互作用。这项研究包括降解对藻类生物标志物同位素组成的影响。由于草食是自养生产的最重要的“汇”，了解这一过程中的结构/同位素变化对于解释下沉和沉积有机质中藻类降解产物的分布和同位素组成至关重要。为了更好地解释颗粒和沉积有机质中脂类和色素的同位素组成分布，需要这项研究提供的基线信息。这些信息最终将使确定许多生物化学物质的来源生物体成为可能，并在确定推动海洋有机碳循环的过程方面取得重大进展。

The goal of this proposal is to investigate the importance of environmental variables on the isotopic composition of major component biochemicals in phytoplankton. Specifically, the objective is to better understand how nutrient and light- limitations affects distributions and isotopic compositions of individual organic compounds in photosynthetic autotrophs. The study will assess the affects of nutrient limitation and representative species of the major algal biomarkers. To accomplish this, representative species of the major algal classes (i.e., Bacillariophyceace, Prymnesiophyceae, Cyanophyceae and Dinophyceae) will live chemostat growth chambers under a variety of conditions and their isotopic is to determine the effect of zooplankton grazing on the structure and isotopic compositions of lipids and pigments. This will be accomplished by allowing phytoplankton feedstock from one chemostat growth chamber to flow under controlled conditions into a second chamber containing zooplankton. Composition of algal biochemical will be compared with those of the zooplankton to investigate microbial chain interactions. The study includes degradation effects on isotopic compositions of algal biomarkers. Since herbivory is the most important 'sink' for autotrophic production, knowledge of structural/isotopic alterations during this process is critical for interpreting the distributions and isotopic compositions of algal degradation products in sinking and sedimentary organic matter. The baseline information provided by this research is needed to better interpret distributions of isotopic composition of lipids and pigments in particulate and sedimentary organic matter. Such information will ultimately make it possible to determine the source organisms for numerous biochemicals and to make significant advances in identifying processes driving recycling of organic carbon in the ocean.