Evidence for a Terpene-Based Food Chain in the Gulf of Alaska

Abstract

A mixture of 14 C-terpenes was prepared from conifer seedlings and introduced into fresh seawater samples taken near Seward, Alaska. Initial rates of oxidation by the indigenous bacteria were linear and faster than the rates of toluene oxidation. Turnover times were 4 to 19 days. Autoradiographic measurements with 3 H-terpenes indicated that at least 10% of the 0.6 � 10 9 to 2.7 � 10 9 bacteria per liter present could catabolize terpenes. The rate of terpene oxidation, 24 μg of terpenes per g of cells per h with 3 μg of terpenes added per liter, was a constant function of bacterial biomass. The specific affinity of the process was estimated to be between 8.1 and 81 liters/g of cells per h, indicating a high state of induction and the probable presence of terpenes. Terpene-oxidizing bacteria were grown on [ 14 C]alanine and added to fresh seawater samples. Transfer of the bacterial radioactivity into larger particles at a rate of 146 pg/liter per h from the 2.3 � 10 9 organisms added indicated that any terpenes present would participate in the food chain.