Collaborative Research: Interactive Effects of Iron, Light and CO2 on Phytoplankton Community Dynamics in the Ross Sea

本提案的目的是调查对南大洋两种主要水华形成浮游植物分类群硅藻和南极棕囊藻大规模分布和生产的控制。这两类沉积物通过参与碳、硫和营养元素的地球化学循环，对晚第四纪气候变化起着重要作用，也可能是未来环境变化的关键参与者。目前的一个范例是，辐照度和铁的可用性驱动浮游植物在南大洋的动态。然而，最近的工作表明，二氧化碳（CO2）的浓度也可能是重要的结构藻类组合，由于物种的生理差异。该提案研究了铁、光和CO2对南大洋棕囊藻和硅藻的生理、生态和相对优势的相互影响。罗斯海是一个理想的系统，在其中调查的环境因素，调节这两个藻类群体的分布和生产，因为它的特点是两个P.南极洲和硅藻，通常在空间和时间上分离的季节性水华。这项研究将采取跨学科调查的形式，包括实地调查和统计分析的藻类组合物的组成，铁，混合层深度，并在罗斯海南部的CO2水平，再加上船上的实验，以检查硅藻和P.南极洲组合的响应高，低水平的铁，光和CO2在春季和夏季。该项目将提供关于控制南大洋两种主要水华形成浮游植物的生产和分布的一些主要因素以及碳、硫和营养元素的相关生物地球化学循环的资料。这些结果最终可能会提高预测南大洋将如何受到未来气候变化影响并可能调节未来气候变化的能力。该项目还将在多个层面上做出重大的教育贡献，包括计划中的研究生和本科生、博士后、实习教师的研究参与以及社区宣传和教育活动。计划开展一些活动，将该项目与K-12教育结合起来。将在当地学校作专题介绍，讨论研究和研究航行的活动。在巡航期间，每天将与小学教室进行互动电子邮件联系。已建立的网站将用于让学生了解正在进行的研究，并允许研究人员通过文本和下载的图像与学生进行交流。

The objectives of this proposal are to investigate the controls on the large-scale distribution and production of the two major bloom-forming phytoplankton taxa in the Southern Ocean, diatoms and Phaeocystis Antarctica. These two groups, through their involvement in the biogeochemical cycles of carbon, sulfur and nutrient elements, may have played important roles in the climate variations of the late Quaternary, and they also may be key players in future environmental change. A current paradigm is that irradiance and iron availability drive phytoplankton dynamics in the Southern Ocean. Recent work, however, suggests that carbon dioxide (CO2) concentrations may also be important in structuring algal assemblages, due to species-specific differences in the physiology. This proposal examines the interactive effects of iron, light and CO2 on the physiology, ecology and relative dominance of Phaeocystis and diatoms in the Southern Ocean. The Ross Sea is an ideal system in which to investigate the environmental factors that regulate the distribution and production of these two algal groups, since it is characterized by seasonal blooms of both P. Antarctica and diatoms that are typically separated in both space and time. This study will take the form of an interdisciplinary investigation that includes a field survey and statistical analysis of algal assemblage composition, iron, mixed layer depth, and CO2 levels in the southern Ross Sea, coupled with shipboard experiments to examine the response of diatom and P. Antarctica assemblages to high and low levels of iron, light and CO2 during spring and summer. This project will provide information on some of the major factors controlling the production and distribution of the two major bloom forming phytoplankton in the Southern Ocean and the related biogeochemical cycling of carbon, sulfur and nutrient elements. The results may ultimately advance the ability to predict how the Southern Ocean will be affected by and possibly modulate future climate change. This project will also make significant educational contributions at several levels, including the planned research involvement of graduate and undergraduate students, postdoctoral associates, a student teacher, and community outreach and educational activities. A number of activities are planned to interface the project with K-12 education. Presentations will be made at local schools to discuss the research and events of the research cruise. During the cruise there will be daily interactive email contact with elementary classrooms. Established websites will be used to allow students to learn about the ongoing research, and to allow researchers to communicate with students through text and downloaded images.