40 Chapter 1 Chapter 2 combines fieldwork, biogeochemistry, methane oxidation, activity assays, and metagenomics to identify the controls and distinct mechanisms that define the microbial community structure and dynamics specifically focusing on ANME archaea activity in the eutrophic coastal sediments of the Stockholm Archipelago. Chapter 3, similar to Chapter 2, employed coastal sediment from the Stockholm Archipelago to inoculate two anoxic methane-saturated bioreactors. These initial coastal sediment microbiomes were subjected to either high or low nitrogen (nitrate and ammonium) and sulfide regimes as well as an increase in salinity under long-term brackish conditions. By combining physicochemical parameters and metagenomics, we monitored the methanotrophic and sulfide-oxidizing community and nitrogen reduction processes over a year and half. In Chapter 4, analogous to Chapter 3, we employed bioreactor systems fed with sulfide, methane, and ammonium, and dependent on nitrate to investigate ammonium removal and the effects of sulfide and nitric oxide toxicity on a stable co-culture that included: N-DAMO, sulfide-oxidizing denitrifiers, and anammox bacteria. Physicochemical parameters, metagenomics, and metatranscriptomics were combined to establish microbial community stability over time and its transcriptional responses to nitrogen deprivation and sulfide and nitric oxide stressors. In Chapter 5, we relied on an enrichment culture of the anaerobic methanotroph “Ca. Methanoperedens” as an ANME study model to study the physiological response to sulfide stress. Here, we established sulfide inhibitory and resistance thresholds and profiled the active methanotrophic community´s response to the coastal ecosystem stressor of interest. We employed a highly enriched culture of “Ca. Methanoperedens” spp. that also included the nitritescavenging N-DAMO partner “Ca. Methylomirabilis” spp., integrating methane oxidation activity assays, physicochemical measures, and specific storage polymers or polyhydroxyalkanoates (PHAs) analysis with metagenomics and metatranscriptomics.
RkJQdWJsaXNoZXIy MTk4NDMw