State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China.
Department of Environmental Biology, The University of Adelaide, Adelaide, South Australia 5005, Australia.
Sci Total Environ. 2015 Jun 15;518-519:24-30. doi: 10.1016/j.scitotenv.2015.02.090. Epub 2015 Mar 3.
It has been hypothesized that climate change will induce the areal extension of cyanobacterial blooms. However, this hypothesis lacks field-based observation. In the present study both long-term historical data and short-term field measurement were used to identify the importance of changes in wind patterns on the cyanobacterial bloom in Lake Taihu (China), a large, shallow, eutrophic lake located in a subtropical zone. The cyanobacterial bloom mainly composed of Microcystis spp. recurred frequently throughout the year. The regression analysis of multi-year satellite image data extracted by the Floating Algae Index revealed that both the annual mean monthly maximum cyanobacterial bloom area (MMCBA) increased year by year from 2000 to 2011, while the contemporaneous cyanobacterial biomass showed no significant change. However, the correlation analysis shows that MMCBA was negatively correlated with wind speed. Our short-term field measurements indicated that the influence of wind on surface cyanobacterial blooms is that the Chlorophyll-a (Chla) concentration is fully mixing throughout the water column when the wind speed exceed 7 m s(-1). At lower wind speeds, there was vertical stratification of Chla with high surface concentrations and an increase in bloom area. The regression analysis of wind speed indicates that the climate has changed over the last decade. Lake Taihu has become increasingly calm, with the decrease of strong wind frequency between 2000 and 2011, corresponding to the increase in the MMCBA over time. Therefore, we conclude that changes in wind patterns related to climate change have favored the increase of cyanobacterial blooms in Lake Taihu.
有人假设气候变化将导致蓝藻水华的面积扩大。然而，这一假设缺乏基于实地的观测。本研究结合长期历史数据和短期野外测量，确定了风向变化对中国太湖（一个位于亚热带地区的大型浅水富营养化湖泊）蓝藻水华的重要性。以微囊藻为主的蓝藻水华频繁发生于全年。对浮游藻类指数提取的多年卫星图像数据的回归分析表明，2000 年至 2011 年期间，年平均每月最大蓝藻水华面积（MMCBA）逐年增加，而同期蓝藻生物量并无显著变化。然而，相关分析表明 MMCBA 与风速呈负相关。我们的短期野外测量表明，风对水面蓝藻水华的影响是，当风速超过 7 m s(-1)时，Chla 浓度在整个水柱中完全混合。在较低的风速下，Chla 出现垂直分层，表面浓度较高，水华面积增加。风速的回归分析表明，过去十年气候发生了变化。太湖变得越来越平静，2000 年至 2011 年间强风频率减少，与 MMCBA 的时间变化相对应。因此，我们得出结论，与气候变化有关的风向变化有利于太湖蓝藻水华的增加。
