| dc.description.abstract | Ammonia-oxidising archaea (AOA) are dominant in nutrient-scarce marine sediments and are important primary producers sustaining the activity of other microorganisms. They are also assumed to be globally important producers of vitamin B12, which is essential to all living organisms. Previous research has shown that AOA are inhibited by various organic compounds, including methanol. Therefore, we aimed to assess how AOA are affected by the presence of methanol in concentrations corresponding to treated wastewater.
The aim was addressed by enriching AOA in marine sediments using a microcosm approach. Sediments enriched with AOA were thereafter exposed to methanol in concentrations simulating treated wastewater. The microbial activity was monitored by measuring the pH, ORP, and concentration of nitrogen species in the microcosms. Metabarcoding and qPCR were employed to assess the microbial diversity and metabolic potential in the microcosm sediments. To ensure proper targeting of archaeal DNA, a preliminary primer evaluation was carried out.
We did observe signs of ammonia-oxidising activity, although we could not attribute it to AOA. While the relative abundance of AOA decreased in the presence of methanol, there were little signs of an absolute decrease in their abundance. Altogether, we did not observe a direct inhibition of AOA by methanol, possibly due to the initially low concentration of methanol. Unexpectedly, the main archaeal response to methanol was the enrichment of Methanosarciniales, which might have contributed to keeping the concentration of methanol at a minimum by converting it to methane. We conclude that the interplay between AOA and methane-producing archaea might be an interesting aspect for further investigation. | |
