DISTRIBUTIONS OF FREE AMINO ACIDS IN SEA AND LAKE ICE CORES FROM ANTARCTICA WITH SPECIAL REFERENCE TO ICE BIOTA (16th Symposium on Polar Biology)

摘要

Dissolved free amino acids (DFAA) of sea ice cores and lake ice cores collected from the vicinity of Davis Station, Antarctica were determined by HPLC. The results of DFAA analysis showed that concentrations of total DFAA in ice cores were higher compared to those in water and they varied from 8.0 μM to 30.9μM and 14.0 μM to 45.0 μM in the sea and lake ice cores, respectively. The highest concentration of total DFAA in the sea ice core appeared in the bottom of 150cm depth, while that in the lake ice core was found in the middle part of the 60-70 cm depth. The relative compositions of individual amino acids, such as serine, histidine and ornithine, which were present in higher concentrations, were similar in both types of ice cores. The variation in the total concentration of DFAA was related to the variation in microalgal cell numbers in the sea ice cores. These DFAA were probably derived from metabolism of the dominant organisms in the algal assemblage ice community. These amino acids are stored in the ice as a large portion of the dissolved organic matter (DOM). It is assumed that these amino acids might be a source of carbon and nitrogen for phytoplankton and/or other microorganisms which bloom during (the next) summer season in the water column.