The degree to which climate variability and anthropogenic stressors have impacted the rich array of boreal lakes in northern Saskatchewan and Alberta was explored in a dataset of 42 lakes from previous paleolimnological investigations of this region. This dataset was used to evaluate the extent of change in diatom assemblages over the past ~ 60 to 70 years in relation to lake and watershed characteristics. Similarity analysis was used to define the degree of change in diatom composition in lake sediment cores from each lake with a focus on post ca. 1945 changes to establish a common time frame to compare across all lakes. This time frame incorporates pre- and post-development of the Athabasca Oil Sands Region and additionally integrates pre- and post-periods of distinct changes in temperature and precipitation. Beta regression analysis was used to identify potential links between diatom assemblage change and lake physical–chemical and landscape characteristics ( limno and landscape models, respectively). Similarity analysis indicated nearly 80% of the lakes showed only a very low degree of change (0–25%) since ca. 1945. Lakes with larger percent change in similarity (> 25%) showed increases in planktonic diatoms, although the specific taxa that changed varied from oligotrophic Discostella spp . to meso-eutrophic taxa, such as Asterionella formosa and Stephanodiscus minutulus . Lake volume and percent peat in the catchment were the most important limno and landscape explanatory variables, respectively, albeit the models had low predictive power. The lakes with large diatom compositional change were dispersed across the region, located in various geological and ecological zones and varying degrees of human disturbance. The interplay of climate and morphometric features of lakes is likely an influential driver of these changes, with larger heat-storage capacity in higher-volume lakes that potentially increases the sensitivity to warming. The small surface areas and shallow morphometry of most lakes, a heterogeneous hydrological and geological landscape, and frequent dominance of diatom assemblages by benthic generalists may explain the minimal responses of diatom assemblages over the past ~ 70 years to anthropogenic influences and climate.

中文翻译：

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自大约以来硅藻组合的异质反应。1945 年在加拿大艾伯塔省北部和萨斯喀彻温省北部地区的湖泊中

气候变异和人为压力因素对萨斯喀彻温省北部和阿尔伯塔省丰富的北方湖泊的影响程度在该地区先前古湖泊学调查的 42 个湖泊的数据集中进行了探索。该数据集用于评估过去 60 至 70 年间与湖泊和流域特征相关的硅藻组合的变化程度。相似性分析用于定义每个湖泊的湖泊沉积物核心中硅藻成分的变化程度，重点是约后。1945 年更改以建立一个共同的时间框架来比较所有湖泊。该时间框架结合了阿萨巴斯卡油砂区的开发前和开发后，另外还综合了温度和降水明显变化的前期和后期。Beta 回归分析用于确定硅藻组合变化与湖泊物理化学和景观特征（分别为 limno 和景观模型）之间的潜在联系。相似性分析表明，近 80% 的湖泊自大约 20 年以来仅表现出非常低的变化程度（0-25%）。1945. 相似性变化百分比较大 (> 25%) 的湖泊显示浮游硅藻增加，尽管改变的特定分类群与寡营养 Discostella spp 不同。到中型富营养化分类群，例如 Asterionella formosa 和 Stephanodiscus minutulus。流域中的湖泊体积和泥炭百分比分别是最重要的湖沼和景观解释变量，尽管这些模型的预测能力较低。硅藻成分变化较大的湖泊分布于全区，地处各个地质生态区，受到不同程度的人为干扰。湖泊的气候和形态特征的相互作用可能是这些变化的一个有影响力的驱动因素，体积较大的湖泊具有更大的蓄热能力，这可能会增加对变暖的敏感性。大多数湖泊的小表面积和浅层形态、水文和地质景观的异质性以及底栖通才对硅藻组合的频繁支配可以解释过去 70 年来硅藻组合对人为影响和气候的最小反应。在体积较大的湖泊中具有更大的蓄热能力，这可能会增加对变暖的敏感性。大多数湖泊的小表面积和浅层形态、水文和地质景观的异质性以及底栖通才对硅藻组合的频繁支配可以解释过去 70 年来硅藻组合对人为影响和气候的最小反应。在体积较大的湖泊中具有更大的蓄热能力，这可能会增加对变暖的敏感性。大多数湖泊的小表面积和浅层形态、水文和地质景观的异质性以及底栖通才对硅藻组合的频繁支配可以解释过去 70 年来硅藻组合对人为影响和气候的最小反应。