Food-Web Regulation of Particulate Export Flux in High Nitrate-Low Chlorophyll Regions

高硝酸盐-低叶绿素地区颗粒物输出通量的食物网调节

• 批准号: 9818770
• 负责人: James Murray
• 金额: $ 43.98万
• 依托单位: University of Washington
• 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: 1999-03-15 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9818770&HistoricalAwards=false
• 关键词: Food; Web; Regulation; Particulate; Export

MurrayUnderstanding the factors that control the magnitude of carbon export from the euphotic zone is one of the most important goals of the US JGOFS Synthesis and Modeling Project (SMP). It is assumed that the magnitude of this export, and its partitioning between particulate and dissolved forms, is determined by the size structure of the food web, but this has never been explicitly tested with models and is subject to debate. A current paradigm is that planktonic systems exist in two contrasting states. Community structure is a function of whether the system is in balance (steady state or State I) or under the influence of transient events - changes in nutrient input, mixing or light - which allow decoupling of phytoplankton and zooplankton growth rates (State II). Export flux and particulate organic matter-dissolved organic matter partitioning are hypothesized to be different between these two states. The high nitrate-low chlorophyll (HNLC) regime is one of the most important ocean types studied during JGOFS. Major process studies were undertaken by US JGOFS in the equatorial Pacific (EqPac) and Southern Ocean (AESOPS) and by Canadian JGOFS in the subarctic north Pacific. Prior to JGOFS, the subarctic north Pacific at Station P was studied by SUPER (Subarctic Pacific Ecosystem Research). The goals of this study are to 1) synthesize and analyze data from HNLC regimes worldwide, 2) use a 1-D model to explore the implications of different grazing formulations for ecosystem function and particulate organic carbon export in HNLC regions, 3) assess the relative importance of particulate and dissolved export, including the role of bacteria and zooplankton as remineralizers, 4) evaluate the elemental stoichiometric relationships that link the various reservoirs, and 5) explore the use of allometric relationships for production and consumption as a tool for understanding and modeling multiple states in HNLC regions. The overall goal is to provide a HNLC synthesis for the SMP of euphotic zone production, consumption and export of carbon and related elements (SMP Element 2), as regulated by variations in environmental conditions.

美国JGOFS综合与模拟项目（SMP）的重要目标之一是了解控制真光层碳输出量的因素。 据推测，这种输出的大小及其在颗粒物和溶解形式之间的分配是由食物网的尺寸结构决定的，但这从未用模型进行过明确测试，并且存在争议。 目前的一个范例是，双稳态系统存在于两种截然不同的状态中。 群落结构是系统是否处于平衡状态（稳态或状态I）或受瞬时事件（营养物输入、混合或光照变化）影响的函数，这些瞬时事件允许浮游植物和浮游动物生长速率脱钩（状态II）。 输出通量和颗粒有机物溶解有机物分配被假设为这两个国家之间是不同的。 高硝酸盐-低叶绿素（HNLC）体系是JGOFS期间研究的最重要的海洋类型之一。 主要的过程研究是由美国联合全球海洋观测系统在赤道太平洋和南大洋进行的，加拿大联合全球海洋观测系统在亚北极北太平洋进行的。 在JGOFS之前，SUPER（亚北极太平洋生态系统研究）对P站的亚北极北太平洋进行了研究。 本研究的目的是1）综合和分析来自全球HNLC制度的数据，2）使用一维模型探索不同放牧配方对HNLC地区生态系统功能和颗粒有机碳输出的影响，3）评估颗粒和溶解输出的相对重要性，包括细菌和浮游动物作为微生物的作用，4）评估链接各种储层的元素化学计量关系，以及5）探索使用生产和消费的异速生长关系作为理解和建模HNLC区域中的多个状态的工具。 总体目标是提供HNLC合成，用于碳和相关元素（SMP元素2）的透光层生产、消耗和输出的SMP，如由环境条件的变化所调节的。