Integrating bacterial metabolism as a key modulator of the response of aquatic ecosystems to human disturbances

淡水生态系统是嵌入陆地景观的地球化学热点，经历了人类驱动的快速变化，如农业和城市化。这一作用的核心是异养细菌的代谢活动 *，除了为水生食物网提供营养和能量外，异养细菌还负责内陆沃茨转运的有机物的大部分降解 * 和矿化。尽管在生态系统水平上认识到了这一作用，但人们对人为干扰如何以及在多大程度上通过改变传递到周围沃茨的有机物的数量、化学性质和年龄来改变水生微生物群落的代谢和功能知之甚少。在微生物生态学和水生生物地球化学的接口进行研究，我建议进一步了解微生物代谢和OM的分子特性之间存在的联系，以更好地理解和预测内陆水体对人类活动的整体生态系统响应。我 * 研究计划的主要目标是：（i）确定释放到 * 水生界面沿着梯度在土地覆盖从森林景观 * 农业和城市地区的有机分子，（ii）评估参与 * 动员有机池的人类活动的吸收微生物策略，和（iii）* 确定水生细菌群落沿着 * 扰动梯度的代谢反应。依靠国家的最先进的技术在分析 * 化学和独特的实验方法，我的研究计划将结合联合收割机 * 时间和空间领域为基础的调查在魁北克省的Mauricie地区 * 利用大梯度的人为影响存在于这一地区，以及 * 实验室检测揭示到细菌的战略资源 * 利用在代表性的影响系统。这个项目代表了一个关键的步骤，使我们更全面地了解人类活动如何不仅破坏了陆地-水界面的元素流动，而且破坏了水生食物网和生态系统的功能。这一认识反过来将使科学家和决策者能够预测水生生态系统和食物网对人类压力的反应，并指导受影响流域最紧迫的恢复工作。

Freshwater ecosystems are biogeochemical hotspots embedded in the*terrestrial landscape that undergoes rapid human-driven changes such as*agriculture and urbanization. Central to this role are the metabolic activities*of heterotrophic bacteria, which are responsible for most of the degradation*and mineralization of the organic matter (OM) transiting in inland waters in*addition to providing nutrients and energy to the aquatic food web. Despite the*recognition of this role at the ecosystem level, little is known about how and*to which extent anthropogenic disturbances may alter the metabolism and*functioning of aquatic microbial communities through changes in the amount,*chemical character, and age of the OM delivered to surrounding waters.*Conducting research at the interface of microbial ecology and aquatic*biogeochemistry, I propose to further our understanding of the links existing*between microbial metabolism and the molecular properties of OM across*perturbation gradients to better understand and predict the overall ecosystemic*response of inland waterbodies to human activities. The main objectives of my*research program are to: (i) identify the organic molecules released into the*aquatic interface along gradients in land-cover from forested landscapes to*agriculture and urban areas, (ii) assess the microbial strategies involved in*the uptake of the mobilized organic pool by human activities, and (iii)*determine the metabolic response of aquatic bacterial communities along*perturbation gradients. Relying on state-of-the-art technics in analytical*chemistry and unique experimental approaches, my research program will combine*temporal and spatial field-based surveys in the Mauricie region of Québec*taking advantage of the large gradient in anthropogenic influence present in this region, as well*as laboratory assays shedding light into the bacterial strategies of resource*utilization in representative impacted systems. This program represents a*crucial step towards an integrative understanding of how human disturbance may disrupt not only the flow of elements at the land-water interface, but also*the functioning of aquatic food webs and ecosystems. This understanding will in*turn allow scientists and policy makers to forecast the response of aquatic*ecosystems and food webs to human pressure and to direct the most pressing*restoration efforts in impacted watersheds.