Sammanfattning

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.

Nyckelord

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

Publicerad i

Science of the Total Environment
2019, Volym: 661, sidor: 148-154
Utgivare: ELSEVIER SCIENCE BV

SLU författare

• Choudhury, Maidul

  • Institutionen för vatten och miljö, Sveriges lantbruksuniversitet
    
  • Lunds Universitet

Globala målen

SDG13 Vidta omedelbara åtgärder för att bekämpa klimatförändringarna och dess konsekvenser


UKÄ forskningsämne

Ekologi


Publikationens identifierare

DOI: https://doi.org/10.1016/j.scitotenv.2019.01.177

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/98614