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

淡水生态系统是地球化学热点， 经历人类驱动的快速变化的陆地景观，如 农业和城市化。这一作用的核心是代谢活动 异养细菌，这是负责大部分的降解 内陆沃茨中有机质（OM）的迁移和矿化 除了为水生食物网提供营养和能量之外。尽管 尽管人们认识到这一作用在生态系统一级的重要性， 在何种程度上人为干扰可能会改变新陈代谢， 水生微生物群落的功能通过数量的变化， 化学性质和释放到周围沃茨的有机物的年龄。 在微生物生态学和水生生物学的界面进行研究 地球化学，我建议进一步了解现有的联系 微生物代谢和OM的分子特性之间的关系 扰动梯度，以更好地了解和预测整体生态系统 内陆水体对人类活动的响应。我的主要目标 研究计划是：（一）确定释放到有机分子 水界面沿着梯度的土地覆盖从森林景观， 农业和城市地区，（ii）评估参与的微生物策略 人类活动对被调动的有机库的吸收，以及（iii） 确定沿着水生细菌群落的代谢反应 扰动梯度依靠最先进的分析技术， 化学和独特的实验方法，我的研究计划将结合联合收割机 魁北克省Mauricie地区基于时间和空间的实地调查 利用该地区存在的人为影响的大梯度，以及 作为实验室检测， 在典型的受影响系统中使用。该计划代表了一个 这是综合理解人类干扰如何不仅破坏陆地-水界面要素流动， 水生食物网和生态系统的功能。这种理解将在 科学家和政策制定者可以预测水生生物的反应， 生态系统和食物网对人类的压力，并直接最紧迫的 受影响流域的恢复工作。

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.