Algae blooms are frequently triggered owing to the improvements in aquatic trophic levels. The aggregated algae from these blooms are eventually dead and accumulate on sediment surfaces, impacting the microenvironment and phosphorus cycling in aquatic systems. However, research on the effects of naturally dead algal deposition on endogenous P release from sediments is lacking. In this study, we investigated the long-term effects of dead algal deposition at varying concentrations on P release from sediments and the underlying mechanisms by assessing microbial metabolism and community structure. The results showed that following the dead algal deposition, the release of P from sediments to the water column peaked on day 40 (0.14±0.017 mg L^-1 in Amend12) and the SRP exchange capacity reached maximum (6.09 ± 1.63 mg/(cm²·d) in Amend12) at sediment-water interface in phase1 (0-3 day). This might be primarily attributed to the deposition of dead algae introducing much organic matter (such as organic carbon and organic phosphorus), thus altering the sediment microenvironment, which increased the activity of phosphorus-cycle microorganisms, such as polyphosphate-accumulating organisms, through increasing C source metabolism, reducing intracellular ammonia inhibition, and creating more suitable anaerobic conditions. Therefore, this study has improved our understanding of the management strategies for controlling endogenous phosphorus release in eutrophic shallow lakes, suggesting that the priming effects of freshly deposited algae could be mitigated by harvesting algae at the peak of blooms.

中文翻译：

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死藻沉积对沉积物表面的长期影响：沉积物中内源性磷释放的行为


由于水生营养水平的提高，经常引发藻类大量繁殖。这些水华产生的聚集藻类最终会死亡并积聚在沉积物表面，影响水生系统中的微环境和磷循环。然而，缺乏关于自然死亡藻类沉积对沉积物中内源性 P 释放的影响的研究。在这项研究中，我们通过评估微生物代谢和群落结构，研究了不同浓度的死藻沉积对沉积物中 P 释放的长期影响以及潜在机制。结果表明，在死藻沉积后，沉积物中磷释放到水柱中，在第 40 天达到峰值 （Amend12 中为 0.14±0.017 mg ^L-1），SRP 交换能力在第一阶段 （0-3 d） 沉积物-水界面达到最大值 （6.09 ± 1.63 mg/（cm²·d） 在 Amend12 中）。这可能主要归因于死藻的沉积引入了大量有机物（如有机碳和有机磷），从而改变了沉积物微环境，从而通过增加 C 源代谢、减少细胞内氨抑制和创造更合适的厌氧条件，增加了磷循环微生物的活性，例如多磷酸盐积累生物。因此，这项研究提高了我们对控制富营养化浅水湖中内源性磷释放的管理策略的理解，表明可以通过在水华高峰期收获藻类来减轻新鲜沉积藻类的启动效应。