Anthropogenic‐driven environmental change, including current climate warming, has influenced lake ecosystems globally during the Anthropocene. Phytoplankton are important indicators of environmental changes in lakes and play a fundamental role in maintaining the functioning and stability of these ecosystems. However, the extent to which lake phytoplankton were affected by anthropogenic or climatic forces during the Anthropocene remains unclear. Here, we investigated the 160‐yr‐long dynamics of the phytoplankton community (cyanobacteria and eukaryotic microalgae) in response to anthropogenic forcing in Sihailongwan Maar Lake—a candidate for a Global boundary Stratotype Section and Point for demarcation of the Anthropocene—using DNA metabarcoding and traditional paleolimnological approaches. Our results show a significant decline in phytoplankton diversity and an abrupt shift in community composition around the 1950s, corresponding to the beginning of the “Great Acceleration” period. Specifically, phytoplankton taxa coexistence patterns, niche differentiation, and assembly mechanisms changed significantly after the 1950s. Overall, increases in air temperature and anthropogenic forcing appear to be the dominant controls for community reorganization and diversity decline of the phytoplankton from this deep maar lake. A neutral community model suggests that phytoplankton community composition was mainly controlled by stochastic processes before the 1950s; however, as time progressed, deterministic effects driven by anthropogenic global warming increased. The results of this study imply that anthropogenic perturbations have led to a loss of phytoplankton diversity and a further decline in ecological resilience in deep lakes, with likely knock‐on effects on the productivity and function of lake ecosystems.

中文翻译：

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沉积物 DNA 揭示人类世期间玛珥湖深部浮游植物多样性丧失

人为驱动的环境变化，包括当前的气候变暖，在人类世影响了全球湖泊生态系统。浮游植物是湖泊环境变化的重要指标，在维持这些生态系统的功能和稳定方面发挥着基础性作用。然而，人类世期间湖泊浮游植物在多大程度上受到人为或气候力量的影响仍不清楚。在这里，我们利用 DNA 元条形码研究了四海龙湾玛珥湖浮游植物群落（蓝藻和真核微藻）对人为强迫的 160 年动态变化——人类世全球边界层型剖面和分界点的候选者。和传统的古湖泊学方法。我们的结果显示，在 20 世纪 50 年代左右，浮游植物多样性显着下降，群落组成发生突然变化，对应“大加速”时期的开始。具体来说，浮游植物类群共存模式、生态位分化和组装机制在 20 世纪 50 年代后发生了显着变化。总体而言，气温升高和人为强迫似乎是玛珥湖深部浮游植物群落重组和多样性下降的主要控制因素。中性群落模型表明，20世纪50年代之前浮游植物群落组成主要受随机过程控制；然而，随着时间的推移，人为全球变暖带来的确定性影响不断增加。这项研究的结果表明，人为扰动导致了深湖浮游植物多样性的丧失和生态恢复力的进一步下降，可能对湖泊生态系统的生产力和功能产生连锁反应。