Genetic potential for methane metabolism in the Greenland subglacial ecosystem

• Thesis title in Czech: Genetický potenciál pro metabolismus metanu v grónském subglaciálním ekosystému
• Thesis title in English: Genetic potential for methane metabolism in the Greenland subglacial ecosystem
• Key words: subglaciální ekosystém, ledovce, mikrobiální aktivita, organická hmota, cyklus uhlíku, metan
• English key words: subglacial ecosystem, glaciers and ice sheets, microbial activity, organic matter, carbon cycling, methane
• Academic year of topic announcement: 2016/2017
• Thesis type: diploma thesis
• Thesis language: angličtina
• Department: Department of Ecology (31-162)
• Supervisor: Mgr. Marek Stibal, Ph.D.
• Author: Mgr. Marek Rybár - assigned by the advisor
• Date of registration: 16.12.2016
• Date of assignment: 16.12.2016
• Date of electronic submission: 06.01.2020
• Date of proceeded defence: 03.02.2020
• Opponents: Mgr. Marie Šabacká, Ph.D.

Preliminary scope of work in English

Subglacial environments are a potential reservoir of methane, which can be released into the atmosphere as a consequence of glacial melting and retreat. Methanogenic archaea, which have been shown to be active in subglacial sedimentsoccur here, produce methane via the degradation of organic carbon under anoxic conditions. However, if anaerobic oxidation of methane (AOM) occurs in subglacial environments, the amount of methane that can potentially be released into the atmosphere would be significantly lowered, analogous to sea-bed sediments where AOM is responsible for up to 90% of methane oxidation. Microbes capable of anaerobic oxidation of methane (anaerobic oxidisers of methane, ANME) have been found in subglacial sediments, and there is preliminary evidence that AOM occurs when there is sufficient amount of SO₄^2-, .e.g when subglacial sediment Is export to a fjord. Currently, it is not known if AOM can occur in the subglacial environment where SO₄^2- concentrations are low. The aim of this thesis is to test the following hypotheses about AOM in the subglacial environment.
Hypothesis 1: Methane can be anaerobically oxidised in subglacial environments by a specific group of Euryarchaeota (ANME).
Hypothesis 2: When sulphate (SO₄^2-) is not available, other EAs, such as nitrate (NO₃^-) or ferric iron (Fe³⁺), may be used by the present ANME.
Long-term incubation experiments will be set up with subglacial sediment (from Greenland, Iceland, Svalbard...) and using different EAs (SO₄^2-, NO₃^-, Fe³⁺, O₂) and controls. Measurements of water chemistry (SO₄^2-, NO₃^-, Fe³⁺ ...) and its changes will be conducted using ion chromatography (IC). Headspace concentrations of CH₄ andCO₂ will be measured using gas chromatography (GC). Changes in the microbial community structure will be determined by sequencing 16S rRNA/rDNA amplicons from RNA/DNA extracted from the sediment.