Environmental and Ecological Regulation of Differences and Interactions between Solitary and Colonial forms of Phaeocystis antarctica

南极棕囊藻孤居形式和群居形式之间的差异和相互作用的环境和生态调节

• 批准号: 0440478
• 负责人: Kam Tang
• 金额: --
• 依托单位: College of William & Mary Virginia Institute of Marine Science
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0440478&HistoricalAwards=false
• 关键词: Environmental; Ecological; Regulation; Differences; Interactions

Phaeocystis Antarctica is a widely distributed phytoplankton that forms dense blooms and aggregates in the Southern Ocean. This phytoplankton and plays important roles in polar ecology and biogeochemistry, in part because it is a dominant primary producer, a main component of organic matter vertical fluxes, and the principal producer of volatile organic sulfur in the region. Yet P. Antarctica is also one of the lesser known species in terms of its physiology, life history and trophic relationships with other organisms; furthermore, information collected on other Phaeocystis species and from different locations may not be applicable to P. Antarctica in the Ross Sea. P. Antarctica occurs mainly as two morphotypes: solitary cells and mucilaginous colonies, which differ significantly in size, architecture and chemical composition. Relative dominance between solitary cells and colonies determines not only the size spectrum of the population, but also its carbon dynamics, nutrient uptake and utilization. Conventional thinking of the planktonic trophic processes is also challenged by the fact that colony formation could effectively alter the predator-prey interactions and interspecific competition. However, the factors that regulate the differences between solitary and colonial forms of P. Antarctica are not well-understood. The research objective of this proposal is therefore to address these over-arching questions:o Do P. Antarctica solitary cells and colonies differ in growth, composition andphotosynthetic rates?o How do nutrients and grazers affect colony development and size distribution of P. Antarctica?o How do nutrients and grazers act synergistically to affect the long-term populationdynamics of P. Antarctica? Experiments will be conducted in the McMurdo station with natural P. Antarctica assemblages and co-occurring grazers. Laboratory experiments will be conducted to study size-specific growth and photosynthetic rates of P. Antarctica, size-specific grazing mortality due to microzooplankton and mesozooplankton, the effects of macronutrients on the (nitrogen compounds) relative dominance of solitary cells and colonies, and the effects of micronutrient (Fe) and grazing related chemical signals on P. Antarctica colony development. Because this species is of critical importance in the Southern Ocean, and because this research will provide critical information on factors that regulate the role of P.Antarctica in food webs and biogeochemical cycles, a major gap in knowledge will be addressed. This project will train two marine science PhD students. The investigators will also collaborate with the School of Education and a marine science museum to communicate polar science to a broader audience.

南极棕囊藻（Phaeocystis Antarctica）是一种广泛分布的浮游植物，在南大洋形成密集的水华和聚集体。这种浮游植物在极地生态学和海洋地球化学中起着重要作用，部分原因是它是主要的初级生产者，有机物垂直通量的主要组成部分，以及该地区挥发性有机硫的主要生产者。然而，南极棕囊藻在生理、生活史和与其他生物的营养关系方面也是鲜为人知的物种之一;此外，从不同地点收集的关于其他棕囊藻物种的信息可能不适用于罗斯海的南极棕囊藻。南极洲主要有两种形态：单细胞和粘液菌落，它们在大小、结构和化学成分上有很大差异。单细胞和群体之间的相对优势不仅决定了种群的大小谱，而且决定了种群的碳动态、养分吸收和利用。群体形成可以有效地改变捕食者-猎物的相互作用和种间竞争，这一事实也挑战了传统的营养过程的思维。然而，调节南极洲的孤立和殖民形式之间的差异的因素还没有得到很好的理解。因此，本提案的研究目标是解决这些过度关注的问题：南极洲南极营养物质和食草动物如何影响南极洲的群体发育和大小分布？o营养物和食草动物如何协同作用影响南极洲的长期种群动态？实验将在麦默多站进行，有南极洲的自然组合和共同出现的食草动物。将进行实验室实验，以研究特定尺寸的生长和光合速率的南极洲，特定尺寸的放牧死亡率由于微型浮游动物和中型浮游动物，宏量营养素的影响（氮化合物）的相对优势的孤立细胞和殖民地，和微量营养素（铁）和放牧相关的化学信号的影响南极洲的殖民地发展。由于这一物种在南大洋至关重要，而且这项研究将提供有关调节南极洲在食物网和生物地球化学循环中作用的因素的关键信息，因此将解决知识方面的重大空白。该项目将培养两名海洋科学博士生。调查人员还将与教育学院和海洋科学博物馆合作，向更广泛的受众传播极地科学。