New research demonstrating that fish play an important role in regulating greenhouse gas emissions from lakes has been published this week in Nature Communications.
According to the study, the presence of fish in humic lakes can increase microbial oxidation of methane via a trophic cascade from fish to zooplankton down to microbes so that less methane leaks from the lakes to the atmosphere.
The research team of professor Roger Jones, the University of Jyväskylä, experimentally divided a lake in Finland and manipulated fish populations while tracking how the presence of fish reduced zooplankton abundance which allowed increased development of methane-oxidizing bacteria. As a result, nearly ten times less methane left the lake to the atmosphere.
Their findings are the first to establish that trophic cascades by vertebrate consumers can reach the microbial community and alter microbially-mediated carbon cycling. Globally, humic lakes are very common and most emit methane to some extent. As such, this research has important links to global climate change, as methane is four times as potent a greenhouse gas compared to carbon dioxide.
This work demonstrates that food web structure from fish all the way to microbes can alter interactions between freshwater and the atmosphere, and illustrates the need for combining ecosystem level research at all trophic levels and biogeochemical processes.
Source: Press release of the University of Jyväskylä
Top consumer abundance influences lake methane efflux
- Shawn P. Devlin, Jatta Saarenheimo, Jari Syväranta & Roger I. Jones, Published online: 4 November 2015 | doi 10.1038/ncomms9787