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Research article - Peer-reviewed, 2019

Charophytes collapse beyond a critical warming and brownification threshold in shallow lake systems

Choudhury, Maidul I.; Urrutia-Cordero, Pablo; Zhang, Huan; Ekvall, Mattias K.; Medeiros, Leonardo Rafael; Hansson, Lars-Anders


Charophytes play a critical role for the functioning of shallow lake ecosystems. Although growth of charophytes can be limited by many factors, such as temperature, nutrients and light availability, our understanding about concomitant effects of climate warming and other large-scale environmental perturbations, e.g. increases in humic matter content ('brownification') is still limited. Here we conducted an outdoor mesocosm experiment during 71 days with a common charophyte species, Chara vulgaris, along an increasing gradient of temperature and brownification. We hypothesized the growth of C. vulgaris to increase with temperature, but to level off along the combined temperature and brownification gradient when reaching a critical threshold for light limitation via brownification. We show that C. vulgaris increases the relative growth rate (RGR), main and total shoot elongation, as well as number of lateral shoots when temperature and brownification increased by +2 degrees C and + 100%, respectively above today's levels. However, the RGR, shoot elongation and number of lateral shoots declined at further increment of temperature and brownification. Macrophyte weight-length ratio decreased with increased temperature and brownification, indicating that C. vulgaris allocate more resources or energy for shoot elongation instead of biomass increase at warmer temperatures and higher brownification. Our study shows that C. vulgaris will initially benefit from warming and brownification but will then decline as a future scenario of increased warming and brownification reaches a certain threshold level, in case of our experiment at +4 degrees C and a 2-fold increase in brownification above today's levels. (C) 2019 Elsevier B.V. All rights reserved.


Climate change; Chara vulgaris; Freshwater; Growth rate; Humic substances; Mesocosm

Published in

Science of the Total Environment
2019, volume: 661, pages: 148-154

Authors' information

Choudhury, Maidul Islam (Choudhury, Maidul)
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Choudhury, Maidul I. (Choudhury, Maidul)
Lund University
Urrutia-Cordero, Pablo
Uppsala University
Zhang, Huan
Chinese Academy of Sciences
Ekvall, Mattias
Länstyrelsen i Skåne län
Medeiros, Leonardo Rafael
Federal Institute of Rio Grande do Norte IFRN
Hansson, Lars-Anders
Lund University

Sustainable Development Goals

SDG13 Climate action

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