Increased mean temperatures and temperature variation have been observed around the globe and are projected to continue at an accelerating rate in the future. Although these climatic changes are leading to more extreme temperature anomalies (e.g., heat waves), we still know very little about their effects on cyanobacterial bloom formation. We conducted a mesocosm experiment including treatments either consistently elevated by 4 °C above ambient temperatures or with the same long-term elevation of +4°C, but with more fluctuations in warming - ranging from 0 to +8°C over shorter temporal scales. Here we demonstrate that the mass proliferation of cyanobacteria occurs earlier in the season and shows higher biomasses in response to a constant climatic warming; both cyanobacterial recruitment rates and pelagic growth were affected in spring and summer. In contrast, the warming scenario including increased temperature variation and frequency of heat waves did not intensify the recruitment and pelagic growth of the dominant cyanobacterial taxa in spring, thereby buffering the increase in overall bloom intensity compared to the treatment representing constant climatic warming. These results suggest that a rise in mean temperatures will likely increase the incidence of harmful cyanobacterial blooms in freshwater systems. Our findings also demonstrate that increased temperature variation may alter cyanobacterial community responses in a different manner than expected based upon a constant elevation in mean temperatures. Studies assessing climate change effects should therefore incorporate such patterns of temperature variation projected by climate change models.


Urrutia Cordero, P., Center for Environmental and Climate Research, Department Biology, Lund University, Sweden, pablo.urrutia_cordero@biol.lu.se

Zhang, H., Department Biology, Lund University, Sweden, huan.zhang@biol.lu.se

Chaguaceda, F., Department Biology, Lund University / Department of Ecology and Genetics, Uppsala University, Sweden, fernando.chaguaceda@ebc.uu.se

Geng, H., Department Biology, Lund University , Sweden, 3013807@mail.scuec.edu.cn

Hansson, L. A., Department Biology, Lund University, Sweden, lars-anders.hansson@biol.lu.se


Oral presentation

Session #:SS04
Date: 06/06/2016
Time: 09:15
Location: Sweeney Ballroom B

Presentation is given by student: Yes