Zou Wei, Zhu Guangwei, Xu Hai, Zhu Mengyuan, Guo Chaoxuan, Qin Boqiang, Zhang Yunlin
Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Biology (Basel). 2021 Nov 23;10(12):1222. doi: 10.3390/biology10121222.
Algal blooms are environmental challenges confronting lakes worldwide and are significantly influenced by chlorophyll yields per unit phosphorus (Chl/TP), or nitrogen (Chl/TN). Here, the influence of inter-annual hydrometeorological variations on Chl/TP and Chl/TN were evaluated in eutrophic shallow Lake Taihu, China. Our results demonstrated significant increases ( < 0.001) in both Chl/TN and Chl/TP from 2005 to 2017, and increased Chl yields during the winter months were mainly correlated with higher water temperature and longer sunshine hours, which may cause severer blooms in winter and spring. In remaining months from 2005 to 2017, typical associations between atmospheric stilling (or water level elevation) and higher Chl yields were observed. The results also indicate that atmospheric stilling and water level elevation significantly ( < 0.001) decreased background turbidity and promoted buoyant cyanobacterial biomass, alleviating phytoplankton light limitation. Given the subtropical location, eutrophic status, and high background turbidity of Lake Taihu, light may be the critical limiting factor for summer phytoplankton growth; thus, improved light availability would promote Chl yields until self-shading caused further light limitations. If the mechanism is general, promoting the effect of atmospheric stilling on annual peak Chl in shallow lakes may be greatly underestimated, and our finding will affect future bloom mitigation efforts in such systems.
藻华是全球湖泊面临的环境挑战，并且受到单位磷（叶绿素/总磷，Chl/TP）或氮（叶绿素/总氮，Chl/TN）产生的叶绿素的显著影响。在此，我们评估了中国富营养化浅水湖泊太湖中年际水文气象变化对Chl/TP和Chl/TN的影响。我们的结果表明，2005年至2017年期间，Chl/TN和Chl/TP均显著增加（P < 0.001），冬季叶绿素产量增加主要与较高水温及较长日照时间相关，这可能导致冬季和春季藻华更为严重。在2005年至2017年的其余月份中，观察到大气稳定（或水位上升）与较高叶绿素产量之间的典型关联。结果还表明，大气稳定和水位上升显著（P < 0.001）降低了背景浊度，并促进了漂浮蓝藻生物量，减轻了浮游植物的光照限制。鉴于太湖的亚热带位置、富营养化状态和高背景浊度，光照可能是夏季浮游植物生长的关键限制因素；因此，光照可用性的改善将促进叶绿素产量，直到自我遮荫导致进一步的光照限制。如果该机制具有普遍性，那么大气稳定对浅水湖泊年峰值叶绿素的促进作用可能被大大低估，并且我们的发现将影响此类系统未来的藻华缓解措施。
