Effects of Light and Nitrogen Source on Prochlorococcus Growth

小坎贝尔9417071 最近发现的光合原核生物原绿球藻属，其含有一组独特的色素，包括二乙烯基叶绿素a和B，已被证明是浮游植物群落的重要组成部分，占总叶绿素生物量的25 - 60%。 在亚热带中太平洋，原绿球藻在100米以上的水柱中占主导地位的叶绿素和碳生物量。 本研究的主要目的是研究限制原绿球藻生长和分布的因素。 研究了光照和氮源对原绿球藻不同菌株生长的影响。 具体而言，本研究将在实验室培养的原绿球藻上进行以下实验：1）比较光照和氮源对光合参数的影响（P vs. I和N vs. I）、氮吸收速率和生长速率：2）测定中太平洋不同原绿球藻种群的氮吸收速率;（3）测定NH_4对原绿球藻吸收NO_3和尿素的抑制作用。 除了实验室实验外，还将对北太平洋的ALOHA站进行四次季度航行，在那里将原绿球藻的实地种群与其他浮游植物物种的分布以及深度和营养概况进行比较。 此外，将测定原绿球藻的田间种群的生长速率、光照强度对生长速率的影响以及营养物添加实验。 最后，单克隆抗体探针将被用来提供一种手段，一定的识别和不同的原绿球藻种群的计数。

9417071 Campbell The recently discovered photosynthetic prokaryotes Prochlorococcus spp., which contain a unique set of pigment including divinyl chlorophyll a and b, have been shown to be an important component of the phytoplankton community contributing 25 to 60% of total chlorophyll biomass. In the subtropical central Pacific Ocean, Prochlorococcus dominate in the upper 100 m of the water column in chlorophyll and carbon biomass. The primary goal of this research is this research is to examine the factors which limit the growth and distribution of Prochlorococcus. A primary objective is to investigate the effects of light and nitrogen-source on the growth of different Prochlorococcus strains in culture and in the field. Specifically the research will conduct the following experiments on laboratory cultures of Prochlorococcus: 1) compare the effects of irradiance and nitrogen source on photosynthetic parameters (P vs. I and N vs. I), nitrogen uptake rates and growth rates; 2) determine nitrogen uptake rates of varying Prochlorococcus populations in the central Pacific; and 3) assess the ability of NH4 to inhibit NO3 and urea uptake in Prochlorococcus. In addition to the laboratory experiments, four quarterly cruises will be conducted to station ALOHA in the North Pacific where field populations of Prochlorococcus will be compared with the distribution of other phytoplankton species with depth and nutrient profiles. Further, field populations of Prochlorococcus will be assayed for growth rates, the effects of light intensity on growth rate, and nutrients addition experiments. Finally, monoclonal antibody probes will be used to provide a means of certain identification and enumeration of distinct Prochlorococcus populations.