Collaborative Research: Iron and Light Effects on Phaeocystis antarctica Isolates from the Ross Sea

殖民prymnesiophyte Phaeocystis anaitica是南极大陆架沃茨的一个主要水华形成的藻类，在那里，除了硅藻，它被认为是一个关键物种，在其对区域地球化学循环和生态系统结构的影响。这些沃茨中的铁含量在仲夏至夏末期间降至约0.1 nM的低值，这可能会限制浮游植物（包括P. anaerotica）的生长。然而，与硅藻相反，很少有研究铁或铁和辐照的组合效应对南极原甲藻的生长、生理和生化组成的影响。在本项目中，将从罗斯海南部采集南极磷虾，并在查尔斯顿大学的实验中使用半连续分批培养法进行培养，以研究铁的有效性和辐照度对南极磷虾生长速率、细胞铁配额、浮力、生物硫产量、色素含量、氧化还原蛋白表达和光合效率的影响。 已知Anaeocystis对罗斯海的碳、营养元素和硫的区域生物地球化学循环有重大影响，时间范围从季节到年际。该物种也可能在推断的与冰期-间冰期气候变化有关的流域尺度地球化学循环变化中发挥了核心作用。因此，重要的是要发展一个机制的理解的因素，控制的生长，生理和生化组成的P. anastritica，为了更好地了解罗斯海和更广泛的南大洋的地球化学生态，以及与区域和全球气候的可能联系。这些实验室实验提供的信息，加上最近和正在进行的实地和模拟研究的结果，将大大提高我们预测南极地区将如何受到未来气候变化的影响和调节未来气候变化的能力。

The colonial prymnesiophyte Phaeocystis antarctica is a major bloom-forming alga in Antarctic shelf waters; where, alongside diatoms, it is considered a keystone species in its impact on regional biogeochemical cycling and ecosystem structure. Iron levels in these waters fall to values as low as ~0.1 nM during the mid to late summer, concentrations that are likely to limit the growth of phytoplankton, including P. antarctica. However, in contrast to diatoms, very little work has been conducted to examined the effects of iron, or the combined effects of iron and irradiance, on the growth, physiology and biochemical composition of P. antarctica. In this project, P. antarctica will be collected from the southern Ross Sea and grown in semi-continuous batch cultures for use in experiments at the University of Charleston to investigate the effects of iron availability and irradiance on the growth rate, cellular iron quota, buoyancy, biogenic sulfur production, pigment content, redox-protein expression, and photosynthetic efficiency of P. antarctica. Phaeocystis antarctica is known to have a significant impact on the regional biogeochemical cycles of carbon, nutrient elements and sulfur in the Ross Sea, over timescales ranging from seasonal to interannual. This species may have also played a central role in the inferred basin- scale changes in biogeochemical cycles linked to glacial-interglacial climatic change. Thus it is important to develop a mechanistic understanding of the factors that control the growth, physiology and biochemical composition of P. antarctica, in order to better understand the biogeochemical ecology of the Ross Sea and the wider Southern Ocean, and the possible linkages with regional and global climate. Together with the results of recent and ongoing field and modeling studies, the information provided by these laboratory experiments will substantially improve our ability to predict how the Antarctic region will be affected by and modulate future climate change.