School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, China.
Center for Coastal & Watershed Studies, Hood College, Frederick, MD 21701, USA.
Int J Environ Res Public Health. 2021 Dec 18;18(24):13360. doi: 10.3390/ijerph182413360.
Cyanobacterial blooms can be stimulated by excessive phosphorus (P) input, especially when diazotrophs are the dominant species. A series of mesocosm experiments were conducted in a lake dominated by a cyanobacteria bloom to study the effects of Phoslock, a phosphorus adsorbent. The results showed that the addition of Phoslock lowered the soluble reactive phosphate (SRP) concentrations in water due to efficient adsorption and mitigated the blooms. Once settled on the sediments, Phoslock serves as a barrier to reduce P diffusion from sediments into the overlying waters. In short-term (1 day) incubation experiments, Phoslock diminished or reversed SRP effluxes from bottom sediments. At the same time, the upward movement of the oxic-anoxic interface through the sediment column slightly enhanced NH release and depressed N release, suggesting the inhibition of nitrification and denitrification. In a long-term (28 days) experiment, Phoslock hindered the P release, reduced the cyanobacterial abundance, and alleviated the bloom-driven enhancements in the pH and oxygen. These results suggest that, through suppression of internal nutrient effluxes, Phoslock can be used as an effective control technology to reduce cyanobacteria blooms common to many freshwater systems.
蓝藻水华可以由过量磷（P）输入刺激，尤其是当固氮生物为优势物种时。本研究通过一系列围隔实验，以一个蓝藻水华为主的湖泊为对象，研究了磷吸附剂 Phoslock 的作用。结果表明，Phoslock 通过有效吸附降低了水中的可溶性活性磷酸盐（SRP）浓度，从而缓解了水华。一旦沉淀在沉积物上，Phoslock 就成为一种屏障，减少了从沉积物向表层水扩散的磷。在短期（1 天）培养实验中，Phoslock 减少或逆转了底泥中 SRP 的流出。同时，通过沉积物柱的好氧-缺氧界面的向上移动，略微增强了 NH 的释放并抑制了 N 的释放，表明硝化和反硝化受到抑制。在长期（28 天）实验中，Phoslock 阻碍了 P 的释放，减少了蓝藻的丰度，并缓解了由水华驱动的 pH 和氧气的增加。这些结果表明，通过抑制内部养分流出，Phoslock 可以作为一种有效的控制技术，减少许多淡水系统中常见的蓝藻水华。
