Collaborative Research: Interactive physiological controls of trait expression, nutrient allocation, and the elemental stoichiometry of Synechococcus

浮游植物的元素组成是海洋科学的一个基本属性，因为元素比例(C：N：P)的变化对海洋生物多样性、生态系统功能和大气二氧化碳水平具有广泛的影响。对于控制浮游植物元素比例的机制，有几种相互竞争的假说，包括改变生物多样性和细胞对各种环境变化的生理反应。由于所有可能的驱动因素都存在很强的区域协变性，所以每种假设都同样能很好地预测当前的海洋观测结果。为了验证每个假设，该项目将使用普通浮游植物菌株的连续培养实验，并结合详细的生化分析。所有数据都将被整合到新的基于基因组的代谢模型中。一项外展计划旨在向参观当地州立公园的学生团体描述海洋浮游植物和海洋生态系统功能的重要性。总之，拟议的项目将导致对生物过程如何整合以控制海洋生态系统中浮游生物资源分配的经验和机械理解。浮游植物的C：N：P是海洋科学的一项基本属性，这些比率的变化对海洋生物多样性、生物地球化学功能和大气二氧化碳水平具有广泛的影响。关于控制海洋浮游植物C：N：P的机制，相互竞争的假说是改变浮游植物的生物多样性与营养限制或温度的生理影响。由于强烈的区域协变性，每一种假设都同样能很好地预测当前的海洋观测。该项目将使用代表全球丰富的聚球藻“集体”内主要海洋生物群的生态型的菌株。首先，元素配额和化学计量比将通过使用化学恒化器在营养供应比率(和限制)、温度和生长速度的梯度上进行量化。其次，大分子细胞组成被量化，以直接将观察到的元素差异与生化组成的变化联系起来。第三，将应用全基因组蛋白质分析来确定生长条件以及元素和生化组成的变化如何与特定细胞子系统和相关功能特征的表达相联系。第四，实验数据将被整合到一个基于特征的浮游植物模型中，以量化适应与适应的相对作用。总之，拟议的项目将导致对不同生物组织水平的过程如何整合以控制海洋浮游植物中的C：N：P的经验和机械理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The phytoplankton elemental composition is a fundamental property of ocean science as variation in elemental ratios (C:N:P) have widespread implications for marine biodiversity, ecosystem functioning, and atmospheric CO2 levels. There are several competing hypotheses for mechanisms controlling phytoplankton elemental ratios including shifting biodiversity vs. cellular physiological responses to various environmental changes. Due to strong regional co-variance of all the possible drivers, each hypothesis predicts current ocean field observations equally well. To test each hypothesis, the project will employ continuous culture experiments of common phytoplankton strains combined with detailed biochemical analyses. All the data will be integrated into novel genome-based metabolic models. An outreach program aims at describing the importance of marine phytoplankton and ocean ecosystem functions to student groups visiting a local state park. Together, the proposed project will lead to an empirical and mechanistic understanding of how biological processes integrate to control plankton resource allocations in marine ecosystems. The C:N:P of phytoplankton is a fundamental property of ocean science and variation in these ratios have widespread implications for marine biodiversity, biogeochemical functioning and atmospheric CO2 levels. Competing hypotheses for mechanisms controlling marine phytoplankton C:N:P are shifting phytoplankton biodiversity vs. the physiological impacts of either nutrient limitation or temperature. Due to strong regional co-variance, each hypothesis predicts current ocean field observations equally well. The project will use strains representing ecotypes from major ocean biomes within the globally abundant Synechococcus ‘collective’. First, the elemental quotas and stoichiometric ratios will be quantified across a gradient of nutrient supply ratios (and limitations), temperature, and growth rates using chemostats. Second, the macromolecular cellular composition is quantified to directly link the observed elemental differences with changes in biochemical composition. Third, genome-wide protein analyses will be applied to identify how changes in growth conditions and elemental and biochemical composition are linked to the expression of specific cellular subsystems and associated functional traits. Fourth, experimental data will be integrated into a trait-based phytoplankton model to quantify the relative role of acclimation vs. adaptation. Together, the proposed project will lead to an empirical and mechanistic understanding of how processes at different levels of biological organization integrate to control C:N:P among marine phytoplankton.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.