Related by context. Frequent words. (Click for all words.) 67 isotope ratios 64 oxygen isotope 63 isotopic composition 61 elemental composition 61 oxygen isotopes 60 isotopic 60 biogenic 58 microfossils 58 methane ethane 58 inorganic compounds 57 chemical composition 57 subglacial 57 naturally occuring 57 spectral signatures 57 hydrologic cycle 56 magmas 56 marine sediments 56 abundances 56 biogeochemical 55 fluxes 55 terrestrial ecosystems 55 oxidise 55 photochemistry 55 RNA sequences 55 radiocarbon dates 55 aerosol particles 55 microstructural 55 sulphates 54 sorption 54 colorimetric 54 nitrification 54 spatial scales 54 nitrogenous 54 anion 54 fatty acid composition 54 uranium thorium 54 morphologies 54 biogeochemistry 54 infrared spectroscopy 53 geochemists 53 clathrates 53 methane CH4 53 physicochemical 53 alkanes 53 photosynthetic organisms 53 Fig. 1A 53 Spectroscopic 53 noble gases 53 amphipods 53 solar nebula 53 stable isotope 53 supernatant 53 temperature gradients 53 osmium 53 abiotic 53 diatom 52 plankton blooms 52 diatoms 52 methylation patterns 52 electrochemically 52 prokaryotic 52 biodegraded 52 lavas 52 paramagnetic 52 nitrogen deposition 52 concretions 52 iron oxides 52 tropospheric 52 lunar soil 52 atmospheric methane 52 porphyrin 52 aromatic hydrocarbons 52 particle sizes 52 nanobubbles 52 chemical reactivity 52 biosynthetic pathway 51 magnetic susceptibility 51 methanogens 51 sediment cores 51 forcings 51 bile acid 51 nitrogen fixation 51 inhomogeneous 51 reactive nitrogen 51 diffusive 51 chondrules 51 coprolites 51 ultracold 51 algal biomass 51 hydrothermal activity 51 Lyman alpha 51 phytoplankton blooms 51 interstellar clouds 51 aragonite 51 isoprene 51 carbonate minerals 51 alpha particles 51 systematics 51 lake sediments 51 MgO 51 Schladow