The Pigment-Labeling Method: Calibrating the Method and Understanding its Limitations

P.I.：戈里克提案#：95-04117项目摘要为了了解世界海洋初级生产力的控制，必须将浮游植物生物量和初级生产力的变化理解为物理、化学和生物参数的函数。理想情况下，初级生产量应确定为浮游植物分类群特定生物量和生长率的总和。虽然这种方法目前还不可行，但可以使用十年前引入的叶绿素标记方法来测量浮游植物的生物量和生长率。原则上，类胡萝卜素的14C标记也可以确定分类单元的特定生长率。然而，这些潜在的强大方法一直在有限的基础上使用，因为缺乏对正在测量的东西的机械理解。本研究将研究恒光下氮限制连续培养的微藻中叶绿素a和类胡萝卜素的14C标记动力学，将以前的研究扩展到其他类胡萝卜素、藻类和营养限制生长条件。这项研究还将确定在Diel光循环下生长的藻类以及藻类在生长光照变化时的色素标记动力学，以评估该方法在不均匀生长条件下进行时的局限性。这项研究的结果将有助于研究界其他成员对颜料标记实验的解释。

P.I.: Goericke Proposal #: 95- 04117 PROJECT ABSTRACT To understand the controls of primary production in the world ocean, variations of phytoplankton biomass and primary production must be understood as a function of physical, chemical and biological parameters. Ideally, one would determine primary production as the sum of the products of phytoplankton taxon specific biomass and growth rates. Although this approach is currently not possible, phytoplankton biomass and growth rates can be measured using the chlorophyll-labeling method, which as introduced a decade ago. Taxon specific growth rates can, in principle, also be determined from the 14C labeling of carotenoids. However, these potentially powerful methods have been used on a limited basis because a mechanical understanding of what is being measured was lacking. This research will study the 14C labeling kinetics of chlorophyll a and carotenoids in nitrogen limited continuous cultures of microalgae grown under constant light to extend previous research to other carotenoids, groups of algae, and conditions of nutrient-limited growth. The study will also determine pigment-labeling kinetics in algae grown under a diel photocycle and algae subject to growth irradiance changes to assess the limitations of the method when it is performed under conditions of uneven growth. The results of this study will aid other members of the research community in the interpretation of the pigment labeling experiments.