Triple-element stable isotope analysis of chloromethane emitted and degraded by royal fern and club moss

In this study we explored the potential benefits of triple element isotope analysis (2H, 13C, 37Cl) of CH3Cl emitted by royal fern (Osmunda regalis) and degradation by a club moss (Selaginella kraussiania). CH3Cl emitted by royal fern showed depleted isotopic values for all elements compared to anthropogenically produced CH3Cl which bodes well for the distinction of different sources. Degradation by club moss showed relatively large stable chlorine isotope effects consistent with other dechlorination reactions. Stable hydrogen and stable chlorine isotope fractionation were larger for hydrogen and smaller for carbon which may indicate a yet unreported degradation mechanism for CH3Cl