Lakes play a pivotal role in ecological and biogeochemical processes and have been described as “sentinels” of environmental change. Assessing “lake health” across large geographic scales is critical to predict the stability of their ecosystem services and their vulnerability to anthropogenic disturbances. The LakePulse research network is tasked with the assessment of lake health across gradients of land use on a continental scale. Bacterial communities are an integral and rapidly responding component of lake ecosystems, yet large-scale responses to anthropogenic activity remain elusive. Here, we assess the ecological impact of land use on bacterial communities from over 200 lakes covering more than 660,000 km² across Eastern Canada. In addition to community variation between ecozones, land use across Eastern Canada also appeared to alter diversity, community composition, and network structure. Specifically, increasing anthropogenic impact within the watershed lowered diversity. Likewise, community composition was significantly correlated with agriculture and urban development within a watershed. Interaction networks showed decreasing complexity and fewer keystone taxa in impacted lakes. Moreover, we identified potential indicator taxa of high or low lake water quality. Together, these findings point to detectable bacterial community changes of largely unknown consequences induced by human activity within lake watersheds.

湖泊在生态和生物地球化学过程中发挥着关键作用，被描述为环境变化的“哨兵”。在大地理范围内评估“湖泊健康”对于预测其生态系统服务的稳定性及其对人为干扰的脆弱性至关重要。LakePulse 研究网络的任务是评估大陆范围内土地利用梯度的湖泊健康状况。细菌群落是湖泊生态系统不可或缺的快速响应组成部分，但对人类活动的大规模响应仍然难以捉摸。在这里，我们评估了土地利用对覆盖超过 660,000 km ^{2的 200 多个湖泊的细菌群落的生态影响}横跨加拿大东部。除了生态区之间的群落差异外，加拿大东部的土地利用似乎也改变了多样性、群落组成和网络结构。具体而言，增加流域内的人为影响降低了多样性。同样，社区组成与流域内的农业和城市发展显着相关。相互作用网络在受影响的湖泊中显示出复杂性降低和关键类群减少。此外，我们确定了高或低湖泊水质的潜在指标分类群。总之，这些发现指出了由湖泊流域内的人类活动引起的可检测到的细菌群落变化，这些变化在很大程度上是未知的。