The distribution of phenylalkanes in the modern sediment associated with gas hydrate from the Gulf of Mexico

Phenylalkanes with carbon numbers between 16 and 19, characterized by the main carbon-18, have been identified in the modern sediments collected from gas hydrate area from the Gulf of Mexico. The structure of phenylalkanes with four isomers for every carbon number was determined by means of their mass spectra and previous studies. The distribution of the series characterized by a low molecular mass was similar to the distribution of n-alkane, alkylcyclohexanes and alkylbenzenes in each sample. There were differences in the distribution of the phenylalkane series between the S-1, S-4, S-7, S-9 samples and the S-8, S-10 and S-11 samples. The phenylalkanes might be derived from Archaea associated with anaerobic oxidation of methane (AOM) processes in S-1, S-4, S-7 and S-9 samples according to their distribution resembled with the distribution of the extract from a type of Archaea. The distribution of alkylcyclohexanes and alkylbenzenes in S-1, S-4, S-7 and S-9 sample was found to be similar to each other. The odd-over-even predominance of alkylcyclohexanes was seen as the input of some bacterial.