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: 9905659
• 负责人: Suzanne Strom
• 金额: $ 6.02万
• 依托单位: Western Washington University
• 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=9905659&HistoricalAwards=false
• 关键词: Food; Web; Regulation; Particulate; Export

StromUnderstanding 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.

Strom了解控制真光带碳输出量的因素是美国JGOFS综合和建模项目（SMP）最重要的目标之一。 据推测，这种出口的规模及其在颗粒形式和溶解形式之间的划分是由食物网的大小结构决定的，但这从未经过模型的明确测试，并且存在争议。 当前的范例是浮游系统存在两种截然不同的状态。 群落结构取决于系统是否处于平衡（稳态或状态 I）或是否受到瞬态事件（养分输入、混合或光照的变化）的影响，这使得浮游植物和浮游动物的生长速率脱钩（状态 II）。 假设这两种状态之间的输出通量和颗粒有机物-溶解的有机物分配是不同的。 高硝酸盐-低叶绿素（HNLC）状况是 JGOFS 期间研究的最重要的海洋类型之一。 主要过程研究由美国 JGOFS 在赤道太平洋 (EqPac) 和南大洋 (AESOPS) 以及加拿大 JGOFS 在亚北极北太平洋进行。 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。 本研究的目标是 1) 综合和分析全球 HNLC 制度的数据，2) 使用一维模型探索不同放牧方式对 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再矿化剂的作用，4) 评估元素 连接各个储层的化学计量关系，5) 探索生产和消费中异速生长关系的使用，作为理解和建模 HNLC 地区多种状态的工具。 总体目标是根据环境条件变化的调节，为富光区生产、消耗和出口碳及相关元素（SMP 元素 2）的 SMP 提供 HNLC 合成。