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在 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 异养菌，它们是大部分降解的原因 年内陆水域过渡有机质(OM)的成矿作用 除了为水生食物网提供营养和能量之外。尽管 在生态系统层面上对这一角色的认识，人们对这种作用是如何以及 在多大程度上，人为干扰可以改变新陈代谢和 水生微生物群落的功能通过数量的变化， 化学性质，以及运往周围水域的有机质的年代。 在微生物生态和水生生物的界面上进行研究 生物地球化学，我建议进一步加深我们对现有联系的理解 微生物代谢与有机质分子特性之间的关系 更好地理解和预测整个生态系统的扰动梯度 内陆水体对人类活动的响应。我的主要目标是 研究计划是：(I)识别释放到空气中的有机分子 从森林景观到土地覆盖中梯度的水生界面 农业和城市地区，(2)评估所涉及的微生物战略 人类活动对已动员的有机库的吸收；以及(3) 测定沿线水生细菌群落的代谢反应 微扰梯度。依靠最先进的技术在分析中 化学和独特的实验方法，我的研究计划将结合 魁北克省毛利西地区基于时间和空间的实地调查 也利用了这一地区存在的人为影响的大梯度 随着实验室化验揭示细菌资源的策略 典型受影响系统中的利用率。这个程序代表了一个 朝着综合理解人类干扰如何不仅扰乱陆地-水界面的元素流动，而且还 水生食物网和生态系统的功能。这一理解将在 使科学家和政策制定者能够预测水生生物的反应 生态系统和食物网来应对人类的压力，并将最紧迫的 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.