Related by context. Frequent words. (Click for all words.) 56 methane 56 clathrates 56 potent greenhouse gas 56 biogenic 54 isoprene 54 methanogens 53 aerosol particles 52 nitrification 52 ionize 52 atmospheric methane 52 adsorb 52 Sulfate 52 hydroxyl radicals 51 nanobubbles 51 noble gases 51 naturally occurring mineral 51 arsenate 51 acidify 51 silicates 51 elemental sulfur 51 isotope ratios 51 hydrothermal vent 50 Nitrogen oxides 50 methane hydrates 50 ionised 50 diatoms 50 plankton blooms 50 solar nebula 50 CO -2 50 amphipods 50 phytoplankton blooms 50 Hydrogen sulfide 50 ultra violet radiation 50 isotopic composition 50 naturally occurring 50 Oxidation 50 anaerobic bacteria 50 kerogen 49 water vapor 49 incomplete combustion 49 naturally occurring substance 49 sequester carbon dioxide 49 alpha particles 49 bioaccumulation 49 hydrothermal activity 49 hydrologic cycle 48 methane hydrate 48 polycyclic aromatic hydrocarbons PAHs 48 marine sediments 48 Methane 48 nitrogen fixation 48 CO2 sequestration 48 Arctic permafrost 48 atmospheric nitrogen 48 combustion gases 48 sulphates 48 microfossils 48 Pyrolysis 48 absorbs carbon dioxide 48 gaseous emissions 47 Siberian permafrost 47 lavas 47 explosive eruptions 47 magma chamber 47 Cyanobacteria 47 particles emitted 47 moon Enceladus 47 acidifying 47 exosphere 47 carbonic acid 47 volcanism 47 dioxide 47 thermogenic 47 Gamma rays 47 iron oxides 47 oxidising 47 gasified 47 ejecta 47 lunar soil 47 Conductivity 47 sorption 47 biogeochemical 46 stromatolites 46 magmas 46 N2O 46 gases emitted 46 adsorbed 46 hydride 46 desorption 46 oxygen isotopes 46 hydrological cycle 46 osmium 46 phosphine 46 thermochemical 46 radioactive decay 46 carbonaceous 46 Carbon sequestration 46 ruminant animals 46 meteorite impacts 46 greenhouse warming 46 Earthlike