Chemical and Microbiological Characterization of Phytoplankton Decay

本研究旨在确定水柱中特定藻类生物标志物稳定性的基本信息。研究问题包括：1)随着时间的推移，各种化学类别的质量和数量是如何变化的；2)特定化合物以及化学上定义的有机物类别发生变化的时间框架是什么？ 3)微生物过程通过攻击特定的浮游植物碳库来调节这些变化的作用是什么？这个项目是一个综合的、多学科的方法，旨在预测海洋水柱中光合作用产生的有机物的命运。精心控制的实验室研究正在追踪微生物群落介导的藻类残留物化学成分的变化（如不同的脂质、色素、碳水化合物和氨基酸）。对细菌生物量、产量和代谢的测量同时进行，以提供特定相关化合物的降解率。正在进行的单藻培养实验已经扩展到包括鞭毛藻，目前作为沿海海洋系统中有机碳的主要生产者受到相当大的关注。单藻群落的结果将与实验室培养和现场收集的群落的混合物进行比较，这些群落的组成可以预测和验证。本研究验证了高度不稳定物种的衰变通过增强微生物代谢来控制混合群落的降解率的假设。

This research is designed to determine fundamental information on the stability of specific algal biomarkers in the water column. Research questions include: 1) how do various chemical classes change qualitatively and quantitatively over time; 2) what is the time frame for alteration of specific compounds as well as chemically defined classes of organic matter and 3) What is the role of microbial processes in mediating the changes by attacking specific pools of phytoplankton carbon. This project is an integrated, multidisciplinary approach aimed at predicting the fate of photosynthetically produced organic matter in the marine water column. Carefully controlled laboratory studies are tracking the changes in chemical composition of algal remains (as distinct lipids, pigments, carbohydrates and amino acids) mediated by the microbial community. Measurements of bacterial biomass, production and metabolism are being conducted in tandem to provide degradation rates for specific relevant compounds. Ongoing experiments with unialgal cultures have been extended to include a dinoflagellate, currently receiving considerable attention as a major producer of organic carbon in coastal marine systems. Results with unialgal communities will be compared to mixtures of laboratory cultures and field collected communities whose composition can be predicted and verified. The research tests the hypothesis that the decay of highly labile species control the degradative rates for a mixed community through enhanced microbial metabolism.