Abstract

Molot LA, Schiff SL, Venkiteswaran JJ, Baulch HM, Higgins SN, Zastepa A, Verschoor MJ, Walters D. 2021. Low sediment redox promotes cyanobacteria blooms across a trophic range: implications for management. Lake Reserv Manage. 37:120–142.

Field observations and experimental manipulations with different oxidizing agents including nitrate demonstrate that high sediment redox prevents cyanobacteria blooms in eutrophic freshwaters. Conversely, low sediment redox caused by depletion of dissolved oxygen and nitrate allows blooms to form. This explains why bloom risk increases with phosphorus levels: Higher productivity increases the spatial and temporal extent of low sediment redox. The intermediate link between low redox and cyanobacteria blooms appears to be internal loading of ferrous iron (Fe²⁺) from reduced sediments with diffusion to depths accessible to migrating cyanobacteria, providing a source for their high iron demand. Regardless of whether Fe²⁺ release is the intermediate link, the concept of “low sediment redox as promoter” has major potential to improve bloom management if managers consider the impact of their nutrient management choices, nutrient targets, and in-lake methods on sediment redox. Phosphorus input targets can be adjusted as climate change alters the extent of anoxia, and short-term bloom prediction models that incorporate the sediment redox concept could predict onset of blooms earlier than current models that depend on detection of photosynthetic pigments associated with blooms.

摘要

莫洛特洛杉矶，席夫SL，文基特斯沃兰JJ，鲍尔奇HM，希金斯SN，扎斯特帕A，Verschoor MJ，沃尔特斯D。2021年。低沉积物氧化还原促进营养范围内的蓝细菌开花：对管理的影响。湖后备管理。37：120–142。

现场观察和使用不同氧化剂（包括硝酸盐）的实验表明，高沉积物氧化还原可防止富营养化淡水中的蓝细菌大量繁殖。相反，由于溶解氧和硝酸盐的消耗而导致的低沉积物氧化还原使水华形成。这就解释了为什么绽放风险会随着磷水平的增加而增加：更高的生产率会增加低沉积物氧化还原的时空范围。低氧化还原和蓝藻花序之间的中间联系似乎是内部铁负载从减少的沉积物中扩散出来的亚铁（Fe ²⁺），扩散到可迁移蓝藻可到达的深度，为它们对铁的高需求提供了来源。无论Fe ²⁺是否释放是中间环节，如果管理者考虑养分管理选择，养分目标和湖内方法对沉积物氧化还原的影响，“低沉积物氧化还原作为促进剂”的概念具有改善水华管理的主要潜力。随着气候变化改变缺氧程度，可以调整磷的输入目标，并且结合了沉积物氧化还原概念的短期绽放预测模型可以比目前依赖于检测与绽放相关的光合色素的模型更早地预测绽放的开始。