Dimensions: Collaborative research: Biological controls of the ocean C:N:P ratios

维度：合作研究：海洋 C:N:P 比率的生物控制

• 批准号: 1046368
• 负责人: Kun Zhang
• 金额: $ 57.25万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1046368&HistoricalAwards=false
• 关键词: Dimensions; Collaborative; research; Biological; controls

Intellectual merit. One of the fundamental patterns of ocean biogeochemistry is the Redfield ratio, linking the stoichiometry of surface plankton with the chemistry of the deep ocean. There is no obvious mechanism for the globally consistent C:N:P ratio of 106:16:1 (Redfield ratio), especially as there is substantial elemental variation among plankton communities in different ocean regions. Thus, knowing how biodiversity regulates the elemental composition of the ocean is important for understanding the ocean and climate as a whole -- now and in the future. The conceptual hypotheses for this study are as follows:1. The C:N:P ratio of a cell is constrained by its broad taxonomic group, which determines, for example, whether it has an outer shell, its size, functional metabolism, membrane lipid composition.2. Within a taxon, there is high genetic diversity. Some of this genetic diversity is potentially laterally transferred, or can be lost within taxa, and confers various functional abilities (organic phosphate assimilation, nitrate assimilation, photoheterotrophy, etc.). Functional diversity provides the cell with further flexibility, such as the ability to respond to varying nutrient supply rates/ratios, and affects a cell's C:N:P ratio within the range specified by the taxon.3. Given these taxonomic and genetic constraints, a cell is physiologically plastic and modifies how it allocates cellular resources in response to nutrient supply rates/ratios in the environment.4. The microbial diversity (taxonomic, genetic, and functional) of the surface ocean varies over time and space, driven by many factors in addition to nutrients. The sum of this mixture composes the ecosystem C:N:P, the ratio that Redfield described. Based on this framework, the CoPIs will make field observations of taxon-specific stoichiometry and growth rates, genomic analyses, and conduct laboratory chemostat experiments to improve understanding of how ocean taxonomic, genetic, and functional biodiversity control the stoichiometry of the surface ocean plankton. Their analyses of these data would lead to a mechanistic understanding of variations in the Redfield ratio, both spatially and temporally.Broader impacts. This study will greatly expand knowledge of the genomic diversity among ocean microbes and how this diversity affects biogeochemistry. The stoichiometry of the ocean's microbes is a parameter that nearly every chemical or biological oceanographer uses, from converting measurements made in one element to another, to estimating regional and global nitrogen budgets. The research also has important implications for the global carbon budget and any changes that might result from climate change. Beyond training three postdoctoral scholars and two graduate students, a Gateway Mentoring Program will be established to recruit undergraduates (total of 12) transferring from community colleges in the Southern California area, training and preparing them for careers in research-oriented science. The program will consist of extensive mentoring, research experiences at UCI, internships at BIOS, Princeton, or UCSD, and presentations at national conferences. This intensive mentoring and research experience prepares students well for a career in science, and enhances acceptance to post-graduate schools. The Program will have a very high proportion of underrepresented groups as reflected in the targeted colleges.Integration. To understand mechanistically temporal and spatial variability of the plankton C:N:P ratio, biodiversity must be studied not only at the traditional taxonomic level, but at the genetic and functional levels which dictate organism response to their environment. Data will be integrated into a combined ocean ecological, evolutionary, and biogeochemical model, with flexible stoichiometry, including cellular biochemical allocations. Seeding a coupled physical-biological model of the oceans with multiple competing genotypes enables the exploration of ecological and evolutionary patterns of resource acquisition and C:N:P ratios. Developing a more mechanistic examination of the course of ecology and evolution, in which laboratory and field data define tradeoffs between different growth and nutrient acquisition strategies, would estabblish the framework of adaptive dynamics for determining "evolutionarily convergence". Finally, model outcomes will be evaluated against field data.

智力上的优点。海洋生物地球化学的基本模式之一是雷德菲尔德比，它将表层浮游生物的化学计量与深海的化学联系起来。全球一致的 C:N:P 比例 106:16:1（雷德菲尔德比）没有明显的机制，特别是不同海洋区域的浮游生物群落之间存在很大的元素差异。 因此，了解生物多样性如何调节海洋的元素组成对于现在和未来了解整个海洋和气候非常重要。本研究的概念假设如下： 1． 细胞的C:N:P比率受到其广泛的分类群的限制，该分类群决定了细胞是否有外壳、大小、功能代谢、膜脂组成等。2． 在一个分类单元内，存在高度的遗传多样性。 其中一些遗传多样性可能会横向转移，或者可能在类群内丢失，并赋予各种功能（有机磷酸盐同化、硝酸盐同化、光异养等）。 功能多样性为细胞提供了进一步的灵活性，例如响应不同营养供应率/比率的能力，并在分类单元指定的范围内影响细胞的C:N:P比率。3。 考虑到这些分类学和遗传限制，细胞在生理上是可塑的，并且会根据环境中的营养供应率/比率改变其分配细胞资源的方式。4。 表层海洋的微生物多样性（分类、遗传和功能）随着时间和空间的变化而变化，除了营养物质之外，还受到许多因素的驱动。 这种混合物的总和构成了生态系统 C:N:P，即雷德菲尔德描述的比率。 基于该框架，CoPI将对分类单元特定的化学计量和生长率进行实地观察、基因组分析，并进行实验室恒化器实验，以加深对海洋分类、遗传和功能生物多样性如何控制表层海洋浮游生物的化学计量的理解。 他们对这些数据的分析将导致对雷德菲尔德比率在空间和时间上的变化的机械理解。更广泛的影响。 这项研究将极大地扩展人们对海洋微生物基因组多样性以及这种多样性如何影响生物地球化学的了解。 海洋微生物的化学计量是几乎每个化学或生物海洋学家都使用的参数，从将一种元素的测量值转换为另一种元素的测量值，到估计区域和全球的氮预算。 该研究还对全球碳预算以及气候变化可能导致的任何变化具有重要影响。 除了培训三名博士后学者和两名研究生外，还将设立一个门户指导计划，招收从南加州地区社区学院转来的本科生（共 12 名），为他们从事研究型科学职业提供培训和准备。该计划将包括广泛的指导、UCI 的研究经验、BIOS、普林斯顿大学或 UCSD 的实习，以及在全国会议上的演讲。 这种密集的指导和研究经验为学生在科学领域的职业生涯做好了准备，并提高了研究生院的接受度。 正如目标大学所反映的那样，该计划将有很高比例的代表性不足的群体。整合。 为了了解浮游生物 C:N:P 比率的机械时间和空间变异性，生物多样性不仅必须在传统的分类学水平上进行研究，而且还必须在决定生物体对其环境的反应的遗传和功能水平上进行研究。 数据将被整合到海洋生态、进化和生物地球化学组合模型中，并具有灵活的化学计量，包括细胞生化分配。 建立具有多种竞争基因型的海洋耦合物理生物模型，可以探索资源获取和 C:N:P 比率的生态和进化模式。 对生态学和进化过程进行更加机械化的检查，其中实验室和现场数据定义了不同生长和养分获取策略之间的权衡，这将建立确定“进化收敛”的适应性动力学框架。 最后，将根据现场数据评估模型结果。