Collaborative Research: Bloom Dynamics and Food Web Structure in the Ross Sea: Primary Productivity, New Production and Bacterial Growth

9319222 Ducklow极地海洋中浮游植物的生长季节很短，但很强烈。越来越多的证据表明，在许多南极栖息地，最活跃的时期可能是季节的早期，这一时期在以前的调查中没有得到强调。该项目是一个跨学科项目的一部分，该项目关注的是南极罗斯海一个高产子系统中春季浮游植物繁殖的动态。整个项目将测试与冰融化开始后不久浮游植物爆发有关的假设，控制春季浮游植物生长和生产力的机制，春季高生产力的影响和短期命运，以及从春季到仲夏的过渡条件。这个组成部分将进行一套面向过程的实验，旨在阐明对浮游植物生产力、生长和积累的控制，以及控制南极水域细菌数量和生产力的机制。具体来说，我们将研究硅藻和褐藻主导组合的相对光合作用和营养（硝酸盐、铵）特征，以测试在罗斯海的春季条件下，褐藻是否生长得更快。浮游植物和细菌的生物量、生产力及其相互作用将被测量，以阐明发生的复杂的物理-化学-生物相互作用。本研究将对控制春季浮游植物生长和生产力的机制、春季高生产力的影响和短期命运以及春季到仲夏条件的转变有实质性的了解。最后，由于南极是海洋中最大的高营养、低生物量系统，因此具有最大的封存二氧化碳的潜力，罗斯海浮游植物动力学的知识也将增加我们对南大洋碳水化合物循环的理解。

9319222 Ducklow The growing season for phytoplankton in polar oceans is short, but intense. There is an increasing body of evidence that in many Antarctic habitats, the most active period may be very early in the season, a period that has not been emphasized in previous investigations. This project is part of an interdisciplinary program that focuses on the dynamics of the spring phytoplankton bloom in a highly productive subsystem of the Antarctic, the Ross Sea. The overall program will test hypotheses related to the initiation of the phytoplankton bloom shortly after the onset of ice melt, the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions. This component will conduct a set of process-oriented experiments designed to elucidate the controls of phytoplankton productivity, growth and accumulation as well as the mechanisms which control bacterial abundance and productivity in Antarctic waters. Specifically, the relative photosynthetic and nutrient (nitrate, ammonium) characteristics of diatom- vs. Phaeocystis-dominated assemblages will be examined to test if Phaeocystis simply grows faster under spring conditions in the Ross Sea. Phytoplankton and bacterial biomass, productivity and their interactions will be measured to elucidate the complex physical-chemical-biological interactions which occur. Substantial understanding of the mechanisms controlling phytoplankton growth and productivity in spring, the implications and short-term fate of high productivity in spring, and the transition from spring to midsummer conditions will result from this research. Finally, because the Antarctic is the ocean's largest high-nutrient, low biomass system, and hence has the greatest potential for sequestering carbon dioxide, knowledge of the dynamics of the Ross Sea phytoplankton will also increase our understanding of the carb on cycle of the Southern Ocean.