Collaborative Research: Dissolved Organic Phosphorus: Quantifying Taxon-specific Rates of Hydrolysis and Uptake

合作研究：溶解有机磷：量化特定分类群的水解和吸收率

• 批准号: 0452904
• 负责人: Robert Chant
• 金额: --
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-15 至 2011-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0452904&HistoricalAwards=false
• 关键词: Collaborative; Research; Dissolved; Organic; Phosphorus

Photosynthetic uptake of CO2 by oceanic phytoplankton and the export of the resulting organic carbon to the deep sea comprise a "biological pump" capable of extracting globally significant amounts of CO2 from the atmosphere. Mounting evidence suggests that primary production in two of the larger subtropical ocean gyres, the Western Tropical/Subtropical Atlantic (Sargasso Sea) and the North Pacific Subtropical Gyre, may be controlled by phosphorus availability. There are vanishingly low inorganic phosphorus (SRP) concentrations, sub-nanomolar in some locales, and ratios of inorganic N:P greatly exceed the canonical Redfield Ratio in these environments. In these low SRP regions dissolved organic phosphorus (DOP) may help meet biological phosphorus demand: data collected in the Sargasso Sea shows a 30% decline in DOP inventories during summer stratification. The hydrolysis and assimilation of DOP by primary producers is likely dependent on phytoplankton physiology, and highly variable between taxa, and through space and time. The investigators hypothesize that despite rapid turnover times, chronically low and seasonally invariant SRP concentrations at BATS cannot support measured rates of primary production without utilization of additional P from the DOP pool. Furthermore, inherent physiological differences among microbial taxa represent a significant source of temporal and spatial variability in DOP utilization rates that is yet neither understood nor constrained. The PIs propose to use proven taxon-specific methodologies to: quantify temporal and spatial variability in DOP hydrolysis in the Sargasso Sea; quantify temporal and spatial variability in taxon-specific SRP and DOP uptake rates; quantify whole-community total P uptake rates as well as SRP and model compound DOP uptake and regeneration rates; identify factors regulating rates of DOP hydrolysis and assimilation; and evaluate the role of DOP in supporting primary production in the Sargasso Sea. An understanding of ocean ecosystem function is important on a broad scale. Photosynthetic uptake of CO2 by oceanic phytoplankton and the export of the resulting organic carbon to the deep ocean are a "biological pump" that removes globally significant amounts of CO2 from the atmosphere. This project will help to constrain predictions of the strength of the oceanic biological pump in the Sargasso Sea. If dissolved organic phosphorus supports a significant fraction of primary production in the Sargasso Sea, then diversity in biological metabolic processes in the central oceans plays a greater role in the global carbon cycle than is presently recognized. The investigators will sponsor a minimum of three undergraduate researchers each year, as well as two graduate students. Data generated from the project will be used in problem-based learning modules for courses taught by the investigators, and the curriculum will be submitted to an appropriate digital repository such as www.dlese.org.

海洋浮游植物对CO2的光合作用吸收，并将所得的有机碳出口到深海中，包括一个“生物泵”，能够从大气中提取全球大量的二氧化碳。 越来越多的证据表明，在两个较大的亚热带海洋回旋中的初级生产，西部热带/亚热带大西洋（Sargasso Sea）和北太平洋亚热带陀螺仪可以通过磷的可用性来控制。在某些地区，无机磷（SRP）浓度的无机磷（SRP）浓度消失了，无机N：P的比率大大超过了这些环境中规范的红场比。在这些低的SRP区域中，溶解有机磷（DOP）可能有助于满足生物磷的需求：在萨尔加索海中收集的数据显示，夏季分层期间，DOP库存下降了30％。 主要生产者对DOP的水解和同化可能取决于浮游植物的生理学，以及分类单元之间以及空间和时间之间的高度变化。 研究人员假设，尽管营业额迅速，但蝙蝠处的长期较低和季节性不变的SRP浓度无法支持未经DOP池中其他P的额外P的测量率。此外，微生物分类群中固有的生理差异代表了DOP利用率中时间和空间可变性的重要来源，尚未理解或限制。 PI建议使用经过验证的分类单元特异性方法来：量化Sargasso Sea中DOP水解的时间和空间变异性；量化特定于分类群的SRP和DOP摄取率的时间和空间变异性；量化全社区总P摄取率以及SRP和模型复合DOP摄取和再生速率；确定调节DOP水解和同化速率的因素；并评估DOP在支持Sargasso Sea初级生产中的作用。 对海洋生态系统功能的理解在广泛的规模上很重要。海洋浮游植物对CO2的光合作用摄取以及最终的有机碳出口到深海是一种“生物泵”，它从大气中消除了全球大量的二氧化碳。 该项目将有助于限制萨尔加索海海洋生物泵强度的预测。如果溶解的有机磷支持萨尔加索海中的主要产量，那么中央海洋中生物代谢过程的多样性在全球碳循环中起着比目前所认识到的更大的作用。 调查人员每年至少赞助三名本科研究人员以及两名研究生。 该项目生成的数据将用于研究人员教授的课程的基于问题的学习模块，并且该课程将提交给适当的数字存储库，例如www.dlese.org。