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

Choudhury, Maidul I. LU ; Urrutia-Cordero, Pablo LU ; Zhang, Huan LU ; Ekvall, Mattias K. LU ; Medeiros, Leonardo Rafael and Hansson, Lars Anders LU (2019) In Science of the Total Environment 661. p.148-154
Abstract

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... (More)

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 °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 °C and a 2-fold increase in brownification above today's levels.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Chara vulgaris, Climate change, Freshwater, Growth rate, Humic substances, Mesocosm, Morphology, Submerged macrophyte
in
Science of the Total Environment
volume
661
pages
7 pages
publisher
Elsevier
external identifiers
  • scopus:85060126781
ISSN
0048-9697
DOI
10.1016/j.scitotenv.2019.01.177
language
English
LU publication?
yes
id
1e438fe4-2506-4f34-a9e9-7f6c1a8341d7
date added to LUP
2019-01-28 11:30:45
date last changed
2019-02-20 11:44:41
@article{1e438fe4-2506-4f34-a9e9-7f6c1a8341d7,
  abstract     = {<p>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 °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 °C and a 2-fold increase in brownification above today's levels.</p>},
  author       = {Choudhury, Maidul I. and Urrutia-Cordero, Pablo and Zhang, Huan and Ekvall, Mattias K. and Medeiros, Leonardo Rafael and Hansson, Lars Anders},
  issn         = {0048-9697},
  keyword      = {Chara vulgaris,Climate change,Freshwater,Growth rate,Humic substances,Mesocosm,Morphology,Submerged macrophyte},
  language     = {eng},
  pages        = {148--154},
  publisher    = {Elsevier},
  series       = {Science of the Total Environment},
  title        = {Charophytes collapse beyond a critical warming and brownification threshold in shallow lake systems},
  url          = {http://dx.doi.org/10.1016/j.scitotenv.2019.01.177},
  volume       = {661},
  year         = {2019},
}