Coupled Intensification of Nitrogen and Phosphorus Cycles in the Subtropical North Pacific Ocean

北太平洋副热带氮磷循环的耦合强化

• 批准号: 9906820
• 负责人: David Karl
• 金额: $ 21.18万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9906820&HistoricalAwards=false
• 关键词: Coupled; Intensification; Nitrogen; Phosphorus; Cycles

This project seeks fundamental information on the interactions between nitrogen (N) and phosphorus (P) in the oligotrophic North Pacific Ocean, and their relationships to rates and mechanisms of ecosystem production and export. The research is guided by the following general hypothesis: "Climate-related shifts in the structure of the epipelagic habitat have selected for N2-fixing bacteria, resulting in a coupled intensification of N and P cycling rates which has forced the system from N- to P-limitation with numerous ecological and biogeochemical consequences. This hypothesized shift from N- to P-limitation has affected community structure, rates of gross primary production and export, and the elemental (C, N, P) stoichiometry of dissolved and particulate matter pools. The investigators will conduct a series of field and laboratory experiments designed to evaluate several ecological predictions of this coupled intensification model of nutrient dynamics in the North Pacific Subtropical Gyre with a primary focus on P pool dynamics. The field research will be conducted at Sta. ALOHA (22 degrees 45'N, 158 degrees W) and will complement the ongoing Hawaii Ocean Time-series (HOT) core measurement program. These efforts will focus on: (1) dissolved inorganic P uptake and remineralization rates, (2) dissolved organic P pool production rates, chemical characterizations and bioavailability and (3) physiological and biochemical assessments of Trichodesmium and Prochlorococcus. Knowledge derived from this project will be used to refine our understanding of the oligotrophic North Pacific ecosystem and to predict the response of oceanic habitats to environmental variability and global climate change.

该项目寻求有关北太平洋中氮（N）和磷（P）之间相互作用的基本信息，以及它们与生态系统生产和出口速度和机制的关系。 这项研究以以下一般假设为指导：“与气候相关的栖息地结构中的气候相关转移已选择用于N2固定细菌，从而导致N和P循环速率的耦合加强，这迫使该系统从N-到N-到。具有许多生态和生物地球化学后果的P限制。研究人员将进行一系列田间和实验室实验，以评估北太平洋亚热带回旋中这种养分动力学的耦合强化模型，主要对P池动力学进行了重点。 Aloha（22度45'n，158摄氏度），将补充正在进行的夏威夷海洋时间序列（热）核心测量计划。有机P池生产率，化学特征和生物利用度以及（3）毛d虫和氯环球菌的生理和生物化学评估。 从该项目中得出的知识将用于完善我们对北太平洋生态系统的理解，并预测海洋栖息地对环境变异性和全球气候变化的反应。