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PhD Dissertation: Microorganisms and electron acceptors affecting methane oxidation in freshwater and marine systems

Methane is a strong greenhouse gas, which can be emitted by lakes and seas. It is produced in the sediments, and can travel via the water column to the atmosphere. Methane can be an important part of the internal carbon cycle, via both methane production and consumption. The latter, performed by methane oxidizing (methanotrophic) bacteria or archaea, can greatly reduce methane emissions and also play a vital role in making methane-derived carbon available to members of the microbial community. To oxidize methane, oxygen is required by certain species. Other species require oxygen-free conditions and use another compound, called the electron acceptor, to complete the redox reaction. Additions of sulfate and nitrate to lake water resulted in a strong stimulation of methane removal rates, suggesting these compounds can be used as alternatives to oxygen. DNA studies showed that most likely, not the methane consumer itself, but another organism used these compounds, and that the two species worked together in a combined effort to remove both nitrate and methane from the lake water. In seawater, nitrate and sulfate were most likely not used as oxygen alternatives, as these compounds are rarely found under seawater natural conditions. Iron compounds and organic matter are more likely to be used under those conditions. In the Black Sea, the type of methane consumer that is present, is likely able to use these compounds, although the very low methane removal rates in the Black Sea make it hard to determine the exact processes that are involved.

Start date and time
End date and time
Location
Online
PhD candidate
Sigrid van Grinsven
Dissertation
Microorganisms and electron acceptors affecting methane oxidation in freshwater and marine systems
PhD supervisor(s)
Prof. Dr. J.S. Sinnighe Damste
Prof. Dr. S. Schouten
Co-supervisor(s)
dr. L. Villaneuva