Among the Laurentian Great Lakes, Lake Ontario is the farthest downstream and has the longest history of environmental stress from human activities. Two sediment cores, spanning the last 300 years, from Lake Ontario were analyzed for diatom composition and geochemistry and compared with anthropogenic activities in the surrounding watershed. Despite some regional variation a clear, lake-wide record of cultural eutrophication and recovery is presented in three phases: (1) a largely pre-impact phase (1700s through ~ 1920) dominated by oligotrophic/mesotrophic diatoms and more inorganic sediment accumulation; (2) an accelerated eutrophication phase (1920s to 1980s) reflecting human population growth, watershed modifications and rapid industrial expansion as indicated by increases in nutrient-tolerant diatom taxa and sediment contaminants; and (3) a recovery phase (1980s to present) when diatom-inferred nutrient concentrations trended back to pre-impact levels in response to pollution abatement measures and novel stressors such as dreissenid invaders and climate change. Based on our long-term record, Lake Ontario’s ecosystem continues to evolve in response to contemporary stressors.

在劳伦森五大湖中，安大略湖是下游最远的湖，也是人类活动造成环境压力历史最悠久的地方。对过去 300 年间来自安大略湖的两个沉积岩芯进行了硅藻成分和地球化学分析，并与周围流域的人为活动进行了比较。尽管存在一些区域差异，但湖泊范围内文化富营养化和恢复的清晰记录分为三个阶段：（1）主要是影响前阶段（1700 到 1920 年），以贫营养/中营养硅藻和更多无机沉积物积累为主；(2) 加速富营养化阶段（1920 年代至 1980 年代），反映了人口增长、流域改造和快速工业扩张，如耐营养硅藻类群和沉积物污染物的增加；(3) 恢复阶段（1980 年代至今），此时硅藻推断的养分浓度趋向于回复到影响前的水平，以响应污染减排措施和新的压力因素，例如德莱森入侵者和气候变化。根据我们的长期记录，安大略湖的生态系统不断发展以应对当代压力。