Department of Biology, Memorial University, Newfoundland, Canada.
Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada.
Environ Toxicol Chem. 2019 Jun;38(6):1245-1255. doi: 10.1002/etc.4414. Epub 2019 May 6.
Lake ecosystems are threatened by an array of stressors. An understanding of how food webs and bioaccumulation dynamics respond to these challenges requires the quantification of energy flow. We present a combined, multitracer approach using both polychlorinated biphenyls (PCBs) and stable isotopes to trace energy flow, and to quantify how lake trout feeding strategies have adapted to changes in food web structure in 3 basins of Lake Huron (ON, Canada). This combined tracer approach allows the quantification of dietary proportions (using stable isotopes), which are then integrated using a novel PCB tracer approach that employs knowledge of PCB bioaccumulation pathways, to estimate consumption and quantify energy flow between age cohorts of individual fish across Lake Huron. We observed basin-specific differences in ultimate energy sources for lake trout, with Georgian Bay lake trout deriving almost 70% of their energy from benthic resources compared with 16 and 33% for Main Basin and North Channel lake trout, respectively. These differences in resource utilization are further magnified when they are contrasted with age. The dependency on pelagic energy sources in the Main Basin and North Channel suggests that these populations will be the most negatively affected by the ongoing trophic collapse in Lake Huron. Our study demonstrates the utility of a multitracer approach to quantify the consequences of food web adaptations to changes in aquatic ecosystems. Environ Toxicol Chem 2019;38:1245-1255. © 2019 SETAC.
湖泊生态系统受到多种胁迫因素的威胁。为了了解食物网和生物积累动态如何应对这些挑战，需要对能量流动进行量化。我们采用了一种组合的、多示踪剂方法，同时使用多氯联苯 (PCBs) 和稳定同位素来追踪能量流动，并量化湖鳟的摄食策略如何适应休伦湖 3 个流域（ON，加拿大）食物网结构的变化。这种组合示踪剂方法可用于量化饮食比例（使用稳定同位素），然后使用一种新的 PCB 示踪剂方法将其整合，该方法利用 PCB 生物积累途径的知识来估计消耗，并量化个体鱼在休伦湖各个年龄组之间的能量流动。我们观察到湖鳟最终能源的流域特异性差异，与主流域和北通道湖鳟的 16%和 33%相比，乔治亚湾湖鳟的能量几乎有 70%来自底栖资源。当与年龄进行对比时，这些资源利用的差异更加明显。主流域和北通道对浮游生物能源的依赖表明，这些种群将受到休伦湖正在发生的营养级崩溃的负面影响最大。我们的研究表明，多示踪剂方法可用于量化食物网适应水生生态系统变化的后果。环境毒理化学 2019；38:1245-1255。©2019 SETAC。
