Abstract:

The occurrence percentage and abundance of General Aerobic Hetero-trophic Bacteria (GAB) were determined by using the method of MPN for 182 sub-samples from 10 sediment cores taken from the Canadian basin and the Chukchi Sea at two different culturing temperatures. The results showed that the general occurrence percentage of CAB was quite high, average abundances of GAB at cultured temperatures of 4℃and 25℃were 4.46×10⁷ and 5.47×10⁷ cells·g^-1 (wt), respectively. The highest abundance of GAB occurred at 20～22 cm section in the sediment. CAB abundances changed among the section of sediments, but there is a trend:the abundances at the middle or lower sections were lower than those at upper section. Cultivation at 25℃could improve the occurrence percentage and abundances of GAB,which suggests that the increasing of temperature may change the living circumstances of GAB. The differences of GAB among the latitudes areas indicated that occurrence percentage and abundances of GAB in middle latitude areas were higher than those in the higher or lower latitude areas,and were more obvious at 4℃than those at 25℃. The GAB abundances in sediment under the shallower water seemed to be lower than those in sediments under the deeper water and this status was more obvious at 25℃than that at 4℃.

Key words: The Canadian Basin, the Chukchi Sea, general aerobic heterotrophic bacteria, spatial distribution, sediment core