Collaborative Research: Linking physiological and molecular aspects of diatom silicification in field populations

硅藻是单细胞的真核光自养生物，是海洋中生态最成功和功能最多样化的生物之一。除了贡献了全球初级生产力的五分之一外，硅藻也是海洋中最大的硅化生物群。因此，硅藻形成了碳和硅（Si）循环之间的关键环节。该项目的目标是了解天然硅藻种群硅化过程的分子调控，以更好地了解控制海洋硅藻生产力的过程。通过培养研究和两次研究巡航，本研究将把硅吸收和硅产生的经典测量与硅化相关基因（sig）和蛋白质表达的分子和生化分析结合起来。拟议中的美国西海岸巡航轨道将针对硅和铁（Fe）浓度的梯度，实现以下目标：1)表征sigs的表达模式；2)将sig表达模式与硅浓度、硅摄取动力学和二氧化硅生成速率相关联；3)开发一种方法，将sig的摄取动力学和二氧化硅生成与硅藻活性和生长的sig表达水平归一化，从而更准确地衡量硅藻的活性和生长；4)表征二氧化硅生成和sig表达的日周期性。知识价值：据估计，硅藻每年处理240太摩尔的生物硅，每个硅分子在出口到深海之前要在硅藻体内循环39次。几十年的海洋学和实地研究已经提供了对自然种群中硅吸收和二氧化硅生产动态的详细见解，但需要对影响硅化过程的因素进行分子理解，以进一步了解海洋中硅和碳通量的调节。描述硅化的遗传潜力将提供有关调节硅藻分布和影响原位硅吸收和硅生产速率的因素的新信息。本研究将为自然种群硅化的分子调控和海洋硅限制的生理基础提供重要信息。更广泛的影响：该项目将生理学、分子生物学和生物化学的概念与海洋生态学和海洋学相结合，为不同兴趣的研究人员提供了一个互动的机会。该项目为女性研究人员提供了首次获得PI经验的机会，同时为本科生和研究生提供了优秀的实践，跨学科的培训。此外，服务不足和代表性不足的本科生将参与实验室和实地研究。研究活动还将与罗格斯大学和加州大学圣巴巴拉分校建立的外展项目相结合，开发新的方法，将实地工作产生的科学主题和数据集转化为针对K-12教育工作者、K-12学生和本科生的创新教材。高级人员还将努力开发教育单元，以便在网上和专业发展讲习班上分发。

Diatoms, unicellular, eukaryotic photoautotrophs, are among the most ecologically successful and functionally diverse organisms in the ocean. In addition to contributing one-fifth of total global primary productivity, diatoms are also the largest group of silicifying organisms in the ocean. Thus, diatoms form a critical link between the carbon and silicon (Si) cycles. The goal of this project is to understand the molecular regulation of silicification processes in natural diatom populations to better understand the processes controlling diatom productivity in the sea. Through culture studies and two research cruises, this research will couple classical measurements of silicon uptake and silica production with molecular and biochemical analyses of Silicification-Related Gene (SiRG) and protein expression. The proposed cruise track off the West Coast of the US will target gradients in Si and iron (Fe) concentrations with the following goals: 1) Characterize the expression pattern of SiRGs, 2) Correlate SiRG expression patterns to Si concentrations, silicon uptake kinetics, and silica production rates, 3) Develop a method to normalize uptake kinetics and silica production to SiRG expression levels as a more accurate measure of diatom activity and growth, 4) Characterize the diel periodicity of silica production and SiRG expression.Intellectual Merit: It is estimated that diatoms process 240 Teramoles of biogenic silica each year and that each molecule of silicon is cycled through a diatom 39 times before being exported to the deep ocean. Decades of oceanographic and field research have provided detailed insight into the dynamics of silicon uptake and silica production in natural populations, but a molecular understanding of the factors that influence silicification processes is required for further understanding the regulation of silicon and carbon fluxes in the ocean. Characterizing the genetic potential for silicification will provide new information on the factors that regulate the distribution of diatoms and influence in situ rates of silicon uptake and silica production. This research is expected to provide significant information about the molecular regulation of silicification in natural populations and the physiological basis of Si limitation in the sea.Broader Impacts: This project blends concepts in physiology, molecular biology, and biochemistry with marine ecology and oceanography, providing an opportunity for researchers with diverse interests to interact. This project provides an opportunity for a female researcher to get first-time PI experience and, at the same time, provides excellent hands-on, cross-disciplinary training for undergraduate and graduate students. In addition, underserved and underrepresented undergraduate students will be involved in both lab and field-based research. Research activities will also interface with established outreach programs at both Rutgers and UC Santa Barbara to develop novel methods for translating scientific themes and data sets generated from field work into innovative teaching materials aimed at K-12 educators, K-12 students, and undergraduates. Senior personnel will also work to develop educational units to be distributed online and in professional development workshops.