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 ...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 GAB was quite high, average abundanees of GAB at cultured temperatares of 4℃ and 25℃ were 4.46 ×10^7 and 5.47×10^7 cells·g^-1（wt）, respectively. The highest abundance of GAB occurred at 20 -22 cm section in the sediment. GAB abundances changed among the section of sediments, but there is a trend ： the a-bundances 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 circum-stances 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 low- er than those in sediments under the deeper water and this status was more obvious at 25℃ than that at 4℃.展开更多
The compounds of sterols such as C27 ,C2s ,C29 and C30 are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5,22 as well as 22-,24-. The compound of sterols such as C27 ,C28 ,C29 a...The compounds of sterols such as C27 ,C2s ,C29 and C30 are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5,22 as well as 22-,24-. The compound of sterols such as C27 ,C28 ,C29 are recorded from B2-9 core of the Bering Sea. The double bond position is located at 5-, 5, 22 as well as 22. The composition characteristics of sterols indicate that the substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results are also suggest that the record of abnormal sterols from the surface sediments （2 -0 era）in the Chukchi Sea and the Bering Sea represent the period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments, which indicates the eco - environmental change responding to climatic effect of circumjacent.展开更多
This paper determined the abundance of General Aerobic heterotrophic Bacteria （GAB） in surficial sediments from the Chukchi Sea and the Canadian basin by using MPN and discussed their geographical distribution. The ...This paper determined the abundance of General Aerobic heterotrophic Bacteria （GAB） in surficial sediments from the Chukchi Sea and the Canadian basin by using MPN and discussed their geographical distribution. The result shows that the determination percentages of the GAB were high, even till 100 percentage. The abundance range and averages of GAB for 4℃and 25℃ were from 4.00 × 10^2 to 2.40× 10^6 , 1.71×10^6 ind.·g^-1 （wet sample ） and from 2.40 ×10^5 to 2.40×10^7 , 1.10×10^7 ind. ·g^-1 （wet sample ） respectively. Not only the abundance range but also the averages of GAB in 25℃ were higher than that in 4℃. The abundance of GAB in sediments show a tendency that it is roughly greater in the lower latitudinal area than in the higher latitudinal area. The abundance of GAB increased from east to west as for the longitudinal distribution. With the water depth increasing, the abundance of GAB at 4℃ decreased, but GBA at 25℃ is not changed obviously with water depth. It seems that warmer circumstantial temperature is more suitable for some GAB.展开更多
Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is predominate in the long-c...Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is predominate in the long-chain alkenones from the Chukchi and Bering Sea sediments. The abundance of C37 to C39 unsaturated alkenones changes in an order of C37 > C38 > C39. Based on C37 /C38 ratio, the detected organism precursors of the long-chain alkenones are mainly coccolithophrid (Emiliania huxleyi). By the calibration relationship between U37k and U37k indices, the sea surface paleotemperature in these seas is estimated. The estimated values of U37k vary from 4.147℃ to 5.706℃ , with a mean value of 5.092℃.展开更多
基金sponsored by the national ministry of finance.And as a part of the second Arctic research expedition(CHINARE-2003) which is organized by Polar Expedition Office of State Oceanic Administration of China,we would like to thank the crew on RV Xuelong for their support and assistance.Research funds are supplied by National Natural Science Foundation of China(No.40576060,40376017 and 40176017).
文摘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 GAB was quite high, average abundanees of GAB at cultured temperatares of 4℃ and 25℃ were 4.46 ×10^7 and 5.47×10^7 cells·g^-1（wt）, respectively. The highest abundance of GAB occurred at 20 -22 cm section in the sediment. GAB abundances changed among the section of sediments, but there is a trend ： the a-bundances 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 circum-stances 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 low- er than those in sediments under the deeper water and this status was more obvious at 25℃ than that at 4℃.
文摘The compounds of sterols such as C27 ,C2s ,C29 and C30 are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5,22 as well as 22-,24-. The compound of sterols such as C27 ,C28 ,C29 are recorded from B2-9 core of the Bering Sea. The double bond position is located at 5-, 5, 22 as well as 22. The composition characteristics of sterols indicate that the substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results are also suggest that the record of abnormal sterols from the surface sediments （2 -0 era）in the Chukchi Sea and the Bering Sea represent the period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments, which indicates the eco - environmental change responding to climatic effect of circumjacent.
基金the national ministry of finance。the second Arctic research expedition（CHINARE-2003）National Natural Science Foundation of China（No.40576060, 40376017 and 40176017）.
文摘This paper determined the abundance of General Aerobic heterotrophic Bacteria （GAB） in surficial sediments from the Chukchi Sea and the Canadian basin by using MPN and discussed their geographical distribution. The result shows that the determination percentages of the GAB were high, even till 100 percentage. The abundance range and averages of GAB for 4℃and 25℃ were from 4.00 × 10^2 to 2.40× 10^6 , 1.71×10^6 ind.·g^-1 （wet sample ） and from 2.40 ×10^5 to 2.40×10^7 , 1.10×10^7 ind. ·g^-1 （wet sample ） respectively. Not only the abundance range but also the averages of GAB in 25℃ were higher than that in 4℃. The abundance of GAB in sediments show a tendency that it is roughly greater in the lower latitudinal area than in the higher latitudinal area. The abundance of GAB increased from east to west as for the longitudinal distribution. With the water depth increasing, the abundance of GAB at 4℃ decreased, but GBA at 25℃ is not changed obviously with water depth. It seems that warmer circumstantial temperature is more suitable for some GAB.
基金This study was supported by the First Chinese National Scientific Observation for the Arctic the Development Program of NKBR
文摘Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is predominate in the long-chain alkenones from the Chukchi and Bering Sea sediments. The abundance of C37 to C39 unsaturated alkenones changes in an order of C37 > C38 > C39. Based on C37 /C38 ratio, the detected organism precursors of the long-chain alkenones are mainly coccolithophrid (Emiliania huxleyi). By the calibration relationship between U37k and U37k indices, the sea surface paleotemperature in these seas is estimated. The estimated values of U37k vary from 4.147℃ to 5.706℃ , with a mean value of 5.092℃.
