Jan 11, 2018

Rising pCO2 in Freshwater Ecosystems Has the Potential to Negatively Affect Predator-Induced Defenses in Daphnia

Linda C. Weiss, Leonie Pötter, Annika Steiger, Sebastian Kruppert, Uwe Frost, Ralph Tollrian
Current Biology
  • States that surprisingly little is known about the impact of anthropogenically caused CO2 on freshwater systems due to their more complex biogeochemistry
  • Analyzes long-term data from four freshwater reservoirs and observed a continuous pCO2 increase associated with a decrease in pH, indicating that not only the oceans but also inland waters are accumulating CO2
  • Tests the effect of pCO2-dependent freshwater acidification using the cosmopolite crustacean Daphnia
  • Bases control pCO2-levels on the present global pCO2average for general validity
  • Selects treatments with very high pCO2 levels, assuming a continuous non-linear increase of pCO2, reflecting worst-case-scenario future pCO2levels
  • Finds that such levels of elevated pCO2 reduce the ability of Daphnia to sense its predators and form adequate inducible defenses
  • Determines that pCO2 and not the resulting reduction in pH impairs predator perception
  • Concludes that if pCO2alters chemical communication between freshwater species, this perturbs intra- and interspecific information transfer, which may affect all trophic levels