Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, SE-104 05, Stockholm, Sweden.
Department of Earth & Atmospheric Sciences, University of Nebraska-Lincoln, 126 Bessey Hall, Lincoln, NE, 68588-0340, USA.
Nat Commun. 2021 Sep 17;12(1):5511. doi: 10.1038/s41467-021-25711-3.
Harmful algal and bacterial blooms linked to deforestation, soil loss and global warming are increasingly frequent in lakes and rivers. We demonstrate that climate changes and deforestation can drive recurrent microbial blooms, inhibiting the recovery of freshwater ecosystems for hundreds of millennia. From the stratigraphic successions of the Sydney Basin, Australia, our fossil, sedimentary and geochemical data reveal bloom events following forest ecosystem collapse during the most severe mass extinction in Earth's history, the end-Permian event (EPE; c. 252.2 Ma). Microbial communities proliferated in lowland fresh and brackish waterbodies, with algal concentrations typical of modern blooms. These initiated before any trace of post-extinction recovery vegetation but recurred episodically for >100 kyrs. During the following 3 Myrs, algae and bacteria thrived within short-lived, poorly-oxygenated, and likely toxic lakes and rivers. Comparisons to global deep-time records indicate that microbial blooms are persistent freshwater ecological stressors during warming-driven extinction events.
与森林砍伐、水土流失和全球变暖有关的有害藻类和细菌大量繁殖在湖泊和河流中越来越频繁。我们证明，气候变化和森林砍伐可能会引发反复出现的微生物大量繁殖，从而抑制淡水生态系统数百万年的恢复。从澳大利亚悉尼盆地的地层序列中，我们的化石、沉积和地球化学数据揭示了在地球历史上最严重的大规模灭绝事件——二叠纪末期事件（EPE；约 2.522 亿年前）期间，森林生态系统崩溃后出现的大量繁殖事件。微生物群落在低地淡水和微咸水体中大量繁殖，其藻类浓度与现代大量繁殖时相似。这些在任何灭绝后恢复植被的迹象之前就开始了，但反复出现了超过 100 千年。在接下来的 300 万年里，藻类和细菌在短暂的、低氧的、可能有毒的湖泊和河流中大量繁殖。与全球深时记录的比较表明，在变暖驱动的灭绝事件中，微生物大量繁殖是持续的淡水生态压力源。
