Garner Rebecca E, Taranu Zofia E, Higgins Scott N, Paterson Michael J, Gregory-Eaves Irene, Walsh David A
Department of Biology, Concordia University, Montreal, Quebec, Canada.
Innovative Genomics Institute, University of California, Berkeley, Berkeley, California, USA.
Environ Microbiol. 2025 Jul;27(7):e70159. doi: 10.1111/1462-2920.70159.
Lake ecosystems are increasingly impacted by eutrophication and climate change. Whole-lake experiments have provided ecosystem-scale insights into the effects of freshwater stressors, yet these are constrained to the duration of monitoring programmes. Here, we leveraged multidecadal monitoring records and century-scale paleogenetic reconstructions for experimentally fertilised and unmanipulated lakes in the IISD Experimental Lakes Area of northwestern Ontario, Canada, to evaluate the responses of algal communities to nutrient and air temperature variation. We first validated the paleogenetic analysis of sediment DNA by demonstrating the synchrony of algal community changes with monitoring records. Algal communities underwent significant compositional shifts across experimental nutrient loading regimes and climate periods, with baseline assemblages informed by paleogenetics. Nonlinear regression modelling of algal community change in monitoring and paleogenetic time series showed the expected response that nutrients were strong drivers in fertilised lakes. Paleogenetic records reflected the century-scale impacts of climate warming and its combined effects with eutrophication, previously underestimated by monitoring. The synergy between eutrophication and warming points to eutrophic priming of the food web to respond to rising temperatures. Overall, the paleogenetic integration of algal diversity across habitats and seasons enables the detection of slow-acting climate change on lake ecosystems increasingly altered by nutrient pollution.
湖泊生态系统正日益受到富营养化和气候变化的影响。全湖实验为淡水压力源的影响提供了生态系统尺度的见解，但这些见解受限于监测计划的持续时间。在这里，我们利用了加拿大安大略省西北部国际可持续发展研究所实验湖区中经过实验施肥和未进行人工干预的湖泊的数十年监测记录和世纪尺度的古遗传学重建，来评估藻类群落对养分和气温变化的响应。我们首先通过证明藻类群落变化与监测记录的同步性，验证了沉积物DNA的古遗传学分析。藻类群落在不同的实验养分加载模式和气候时期经历了显著的组成变化，其基线组合由古遗传学提供信息。对监测和古遗传学时间序列中藻类群落变化的非线性回归建模显示了预期的响应，即养分是施肥湖泊中的强大驱动因素。古遗传学记录反映了气候变暖的世纪尺度影响及其与富营养化的综合影响，而此前监测低估了这些影响。富营养化和变暖之间的协同作用表明食物网的富营养化启动作用，以应对气温上升。总体而言，跨栖息地和季节对藻类多样性进行古遗传学整合，能够检测到营养污染日益改变的湖泊生态系统中缓慢发生的气候变化。
