Grosbois Guillaume, Anjum Mou Tasnim, Girona Miguel Montoro
Groupe de Recherche en Écologie de la MRC Abitibi (GREMA), Institut de Recherche sur les Forêts, Université du Québec en Abitibi-Témiscamingue, 341 Rue Principale N, Amos, QC, J9T 2L8, Canada.
Group for Interuniversity Research in Limnology and Aquatic Environments (GRIL), Université de Montréal, Montréal, QC, H3C 3J7, Canada.
Heliyon. 2024 Nov 30;10(24):e40687. doi: 10.1016/j.heliyon.2024.e40687. eCollection 2024 Dec 30.
Lake cyanobacteria can overgrow and form blooms, often releasing life-threatening toxins. Harmful algal blooms (HABs) are typically caused by excess nutrients and high temperatures, but recent observations of cyanobacteria beneath the ice in boreal lakes suggest that the dynamics are more complex. This study investigates the seasonal dynamics of HABs in boreal lakes and identifies their driving factors. We study cyanobacteria assemblages in two boreal lakes in Abitibi-Témiscamingue (Quebec, Canada): Lake Fortune, noted for its under-ice cyanobacteria, and Lake Beauchamp, which has experienced recurrent summer-only cyanobacterial blooms. From June 2021 to July 2022, we identified monthly cyanobacterial communities and estimated water nutrients, organic carbon, temperature, oxygen, and pH. Cyanobacterial communities were dominated by the genus in Lake Fortune, and this genus was in a bloom state for each month of the year. Cyanobacterial abundance was highest (210 000 cells/mL) in November and lowest (28 000 cells/mL) in March. The abundance of correlated with total nitrogen and phosphorus and dissolved organic carbon concentrations. dominated even under ice cover, because of its ability to thrive in low-light and low phosphorus conditions. In Lake Beauchamp, was found throughout the year, highest (27 800 cells/mL) in August and lowest (2100 cells/mL) in March. In Lake Beauchamp, cyanobacterial blooms correlated with total dissolved phosphorus, nitrogen and organic carbon concentrations during summer and fall. The dominance of was especially pronounced during the summer and fall. Our study provides new knowledge about the seasonal dynamics of cyanobacterial blooms to help guide the future management of HABs in boreal lakes.
湖泊蓝藻细菌会过度生长并形成水华，常常释放出危及生命的毒素。有害藻华（HABs）通常由营养物质过剩和高温引起，但最近对北方湖泊冰层下蓝藻细菌的观测表明，其动态变化更为复杂。本研究调查了北方湖泊中有害藻华的季节动态，并确定了其驱动因素。我们研究了加拿大魁北克阿比蒂比 - 特米斯卡明格地区两个北方湖泊中的蓝藻细菌群落：以冰层下蓝藻细菌闻名的财富湖，以及仅在夏季反复出现蓝藻水华的博尚湖。从2021年6月到2022年7月，我们每月识别蓝藻细菌群落，并估算水体中的营养物质、有机碳、温度、氧气和pH值。财富湖中的蓝藻细菌群落以该属为主，且该属在一年中的每个月都处于水华状态。蓝藻细菌丰度在11月最高（210000个细胞/毫升），在3月最低（28000个细胞/毫升）。该属的丰度与总氮、总磷以及溶解有机碳浓度相关。即使在冰层覆盖下该属仍占主导，因为它能够在低光照和低磷条件下茁壮成长。在博尚湖中，全年都能发现该属，8月最高（27800个细胞/毫升），3月最低（2100个细胞/毫升）。在博尚湖，夏季和秋季的蓝藻水华与总溶解磷、氮和有机碳浓度相关。该属在夏季和秋季的优势尤为明显。我们的研究提供了关于蓝藻水华季节动态的新知识，以帮助指导未来北方湖泊有害藻华的管理。
