Dear Gert, we found such values in the DIC of an anoxic basin of lake Untersee, East Antarctica. "The extremely high delta C-13 value (+25.12 permill) of dissolved inorganic carbon (DIC) in the anoxylimnion can be attributed to a certain pathway of methanogenesis ..." Ref.: U. Wand et al., Antarctic Science 9, 43-45 (1997) Best regards Guenter Schwarz ________________________________________________________________________________ Dr. Günter Schwarz Alfred Wegener Institute for Polar and Marine Research Research Unit Potsdam P.O.Box 60 01 49 14401 Potsdam, Germany Tel.: +331 288 2154 Fax: +331 288 2137 ________________________________________________________________________________