Eutrophication has been identified as the primary cause of water quality deterioration in inland waters worldwide, often associated with algal blooms or fish kills. Eutrophication can be controlled through watershed management and in-lake measures. An extreme heatwave event, through its impact on mineralization rates and internal nutrient loading (phosphorus—P, and nitrogen—N), could counteract eutrophication control measures. We investigated how the effectiveness of a nutrient abatement technique is impacted by an extreme heatwave, and to what extent biogeochemical processes are modulated by exposure to heatwaves. To this end, we carried out a sediment-incubation experiment, testing the effectiveness of lanthanum-modified bentonite (LMB) in reducing nutrients and greenhouse gas emissions from eutrophic sediments, with and without exposure to an extreme heatwave. Our results indicate that the effectiveness of LMB may be compromised upon exposure to an extreme heatwave event. This was evidenced by an increase in concentration of 0.08 ± 0.03 mg P/L with an overlying water volume of 863 ± 21 mL, equalling an 11% increase, with effects lasting to the end of the experiment. LMB application generally showed no effect on nitrogen species, while the heatwave stimulated nitrification, resulting in ammonium loss and accumulation of dissolved oxidized nitrogen species as well as increased dissolved nitrous oxide concentrations. In addition, carbon dioxide (CO₂)-equivalent was more than doubled during the heatwave relative to the reference temperature, and LMB application had no effect on mitigating them. Our sediment incubation experiment indicates that the rates of biogeochemical processes can be significantly accelerated upon heatwave exposure, resulting in a change in fluxes of nutrient and greenhouse gas between sediment and water. The current efforts in eutrophication control will face more challenges under future climate scenarios with more frequent and intense extreme events as predicted by the IPCC.

富营养化已被确定为全球内陆水域水质恶化的主要原因，通常与藻类大量繁殖或鱼类死亡有关。富营养化可以通过流域管理和湖内措施加以控制。极端热浪事件通过其对矿化率和内部养分负荷（磷 - P 和氮 - N）的影响，可以抵消富营养化控制措施。我们调查了极端热浪如何影响营养物减排技术的有效性，以及暴露于热浪中对生物地球化学过程的调节程度。为此，我们进行了沉积物孵化实验，测试了镧改性膨润土 (LMB) 在减少富营养化沉积物中养分和温室气体排放方面的有效性，有或没有暴露在极端热浪中。我们的结果表明，LMB 的有效性可能会因暴露于极端热浪事件而受到影响。这可以通过浓度增加 0.08 ± 0.03 mg P/L 和上覆水体积 863 ± 21 mL 来证明，相当于增加了 11%，效果持续到实验结束。LMB 应用通常对氮物种没有影响，而热浪刺激了硝化作用，导致铵损失和溶解的氧化氮物种的积累以及溶解的一氧化二氮浓度增加。此外，二氧化碳（CO 03 mg P/L，上覆水体积为 863 ± 21 mL，相当于增加了 11%，效果持续到实验结束。LMB 应用通常对氮物种没有影响，而热浪刺激了硝化作用，导致铵损失和溶解的氧化氮物种的积累以及溶解的一氧化二氮浓度增加。此外，二氧化碳（CO 03 mg P/L，上覆水体积为 863 ± 21 mL，相当于增加了 11%，效果持续到实验结束。LMB 应用通常对氮物种没有影响，而热浪刺激了硝化作用，导致铵损失和溶解的氧化氮物种的积累以及溶解的一氧化二氮浓度增加。此外，二氧化碳（CO₂ )-当量在热浪期间相对于参考温度增加了一倍以上，并且 LMB 的应用对减轻它们没有影响。我们的沉积物孵化实验表明，暴露于热浪时，生物地球化学过程的速率会显着加快，从而导致沉积物和水之间的养分和温室气体通量发生变化。在IPCC预测的极端事件更加频繁和剧烈的未来气候情景下，当前在富营养化控制方面的努力将面临更多挑战。