Impact of environmental change on the physiological and adaptive responses of aquatic organisms

由于人类活动和全球变暖，动物必须应对的环境压力的范围和可变性正在不断增加。了解动物对这种变化环境的反应是揭示复杂生物过程（如生物体的适应和微进化）背后驱动力的第一步。J. Elser及其同事提出了一种广义的方法，试图将细胞分配与生物体功能和生态动力学联系起来。简而言之，快速生长的生物被认为具有较低的生物量C:P和N:P比率，这反映了快速蛋白质合成所需的富P核糖体RNA （rRNA）的分配增加，以支持快速生长。高生长速率表型的遗传机制与核糖体RNA基因的结构和组织有关，特别是基因间间隔（IGS）长度的异质性。这意味着进化过程可以在主要生活史特征（特定生长率）中产生变异，并由于其对有机元素组成的影响而对生态动力学产生影响。我的研究计划的总体目标是：1)了解变化的环境条件如何影响生理反应，主要是水生生物的生长速度；2)通过识别和研究与生长相关的功能遗传变异来了解水生生物的适应性反应。

As a consequence of human activity and global warming, the range and variability of environmental pressures that animals must cope with is constantly increasing. Understanding animal response to such varying environments is a first step towards uncovering the underlying forces driving complex biological processes, such as adaptation and microevolution of organisms. A broadly generalized approach, developed by J. Elser and colleagues attempts to link cellular allocation to organism function and to ecological dynamics. Briefly, rapidly growing organisms are thought to have low biomass C:P and N:P ratios that reflect an increased allocation to P-rich ribosomal RNA (rRNA) needed for rapid protein synthesis to support fast growth. Genetic mechanisms underlying high growth rate phenotypes implicate the structure and organisation of ribosomal RNA genes, notably heterogeneity in intergenic spacer (IGS) length. This implies that evolutionary processes can generate variation in a major life history trait (specific growth rate) and have consequences for ecological dynamics due to their effects on organismal elemental composition. The general objectives of my research program are: 1) to understand how changing environmental conditions impact physiological responses, mainly the growth rates of aquatic organisms; 2) to understand the adaptive responses of aquatic organisms by identifying and investigating functionally relevant genetic variation implicated in growth. As a model system I will focus mainly on Lake Saint-Pierre (LSP), the largest of the three fluvial lakes in the St. Lawrence River system, presenting important spatial and temporal environmental variations due to a highly complex hydrology. I will proceed to address the connections between growth rate, organism C:N:P and IGS length variation in yellow perch (Perca flavescens) under different conditions of nutrient supply. Using an integrated stoichiometric approach from molecular biology to ecology, my research program will address fundamentally important questions in evolutionary biology in general that have not been otherwise possible using conventional approaches.