The influence of changes in wind patterns on the areal extension of surface cyanobacterial blooms in a large shallow lake in China.
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.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China. Electronic address: tfwu@niglas.ac.cn.
Tingfeng
T
Wu
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China. Electronic address: qinbq@niglas.ac.cn.
Boqiang
B
Qin
Department of Environmental Biology, The University of Adelaide, Adelaide, South Australia 5005, Australia.
Justin D
JD
Brookes
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China.
Kun
K
Shi
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China.
Guangwei
G
Zhu
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China.
Mengyuan
M
Zhu
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, Jiangsu 210098, China.
Wenming
W
Yan
Department of Environmental Science and Engineering, School of Environment and Civil Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.
Zhen
Z
Wang
D002681:China; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D057231:Climate Change; D000458:Cyanobacteria; D004784:Environmental Monitoring; D005068:Eutrophication; D060106:Lakes / Q000382:microbiology*; D014871:Water Microbiology; D014919:Wind
D002734:Chlorophyll; D000077194:Chlorophyll A
Climate change; Hydrodynamics; Lake Taihu; Surface cyanobacterial bloom; Wind pattern change