Collaborative Research: A Critical Examination of the Relationship Between Marine Phytoplankton Growth Rates and Phosphate Concentrations: Monod or Not

合作研究：对海洋浮游植物生长速率与磷酸盐浓度之间关系的严格检验：莫诺与否

• 批准号: 0647873
• 负责人: Paul Bienfang
• 金额: $ 21.88万
• 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: 2007
• 资助国家: 美国
• 起止时间: 2007-03-15 至 2012-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0647873&HistoricalAwards=false
• 关键词: Collaborative; Research; Critical; Examination; Relationship

This project involves the use radioactive phosphorus (33P) as a tracer in chemostat experiments to study the relationship between phosphate concentrations and growth rate in monospecific cultures of marine phytoplankton. For literally decades that relationship has been assumed to be described by the Monod equation, but the inability of colorimetric methods to accurately measure growth-rate-limiting concentrations of phosphate has precluded a rigorous test of this hypothesis. Theoretical analysis indicates that divergence from the Monod equation may be associated with diffusion of the growth-rate-limiting substrate through the boundary layer around the cell. Because the cell quota of limiting nutrient is more variable for phosphorus than nitrogen, it can be shown that the impact of diffusion through the boundary layer on the shape of the growth rate curve is likely to be much greater for phosphorus than for nitrogen. The intellectual merit of the proposed work lies in the use of tracer amounts of 33P to accurately measure phosphate in the nanomolar concentration range and the use of chemostats to provide rigorous control of growth rates. The combination of these methodologies offers by far the best chance of defining the relationship between phosphate concentration and growth rate and hence at last provide a rigorous test of the Monod growth model.The broader impacts of the proposed work include the fact that the research will be a collaborative effort between Louisiana State University (LSU) and the University of Hawaii (UH) and will provide support for a graduate student at each institution. Both LSU and UH are EPSCoR institutions. Dr. Laws has written a textbook titled Mathematical Methods for Oceanographers (John Wiley) and teaches a graduate course at LSU that makes use of that text. The course and text include material on modeling. The results of the proposed work will be integrated into Dr. Laws' course and into future editions of his book and will be submitted for publication in the scientific literature. The broadest impact of the proposed work, however, will be on our understanding of the relationship that controls phytoplankton growth rates in phosphorus-limited systems and the outcome of resource competition among algae. For literally decades that relationship has been assumed to be the Monod equation. This project will use existing the tools to determine whether it is or is not.

该项目涉及在恒化器实验中使用放射性磷（33P）作为示踪剂，研究海洋浮游植物单一培养物中磷酸盐浓度与生长速率之间的关系。几十年来，人们一直认为这种关系可以用莫诺方程来描述，但比色法无法准确测量磷酸盐的生长速率限制浓度，因此无法对这一假设进行严格的检验。理论分析表明，与莫诺方程的偏离可能与生长速率限制基质通过细胞周围边界层的扩散有关。由于磷的限制养分的细胞配额比氮的变化更大，因此可以表明，磷通过边界层的扩散对生长速率曲线形状的影响可能比氮大得多。这项工作的智力优点在于使用 33P 示踪量来精确测量纳摩尔浓度范围内的磷酸盐，并使用恒化器来严格控制生长速率。这些方法的结合提供了迄今为止定义磷酸盐浓度和生长速率之间关系的最佳机会，因此最终提供了对莫诺生长模型的严格测试。拟议工作的更广泛影响包括以下事实：该研究将这是路易斯安那州立大学 (LSU) 和夏威夷大学 (UH) 之间的合作项目，将为每个机构的研究生提供支持。 LSU 和 UH 都是 EPSCoR 机构。劳斯博士编写了一本名为《海洋学家数学方法》（约翰·威利）的教科书，并在路易斯安那州立大学教授一门研究生课程，该课程利用了该教科书。课程和文本包括建模材料。拟议工作的结果将被纳入劳斯博士的课程和他的书的未来版本中，并将提交在科学文献中出版。然而，拟议工作的最广泛影响将在于我们对控制磷限制系统中浮游植物生长速率的关系以及藻类之间资源竞争结果的理解。几十年来，这种关系一直被认为是莫诺方程。该项目将使用现有的工具来确定是否存在。