This research focuses on providing a mechanistic understanding of how bioturbating organisms affect greenhouse gas (GHG) production (through microbial communities), its rates of emission and emission pathways from aquatic ecosystems. For this purpose, a set of animals and plants was selected displaying different modes of action (functional traits) that are widespread geographically. To link bioturbator traits and GHG emission, start-of-the-art methods are used that include the use of mesocosms that allow us to visually monitor gas bubbles in the sediment in situ.
The experiments will be conducted on two sediment types and with and without warming since bioturbation effects can be influenced by these parameters. Moreover, to measure CH4 ebullition we are using bubble traps and a greenhouse gas analyzer for diffusive pathways. For microbial CH4 production,oxidation rates and microbial abundance bottle incubations are used as well as qPCR of functional genes: pmoA (aerobic CH4 oxidation) and mcrA (CH4 production) respectively. δ13C signatures of CH4 in the pore water, surface water, emitted gas as well as emissions will be used to calculate transportation rates.
In addition, the possible relations between bioturbator communities and greenhouse gas emissions in the field will be assessed. Ebullition traps will be placed in 10 sites and 10 controls, and in these sites, benthic flora and fauna community composition will be assessed to further correlate community trait values and GHG emission intensities.