HAYASHI Hidetake Shinshu University, Faculty of Science, Professor, 理学部, 教授 (60087129)
WADA Eitaro Kyoto University, Center for Ecological Research, Professor, 生態学研究センター, 教授 (40013578)
|Budget Amount *help
¥6,200,000 (Direct Cost : ¥6,200,000)
Fiscal Year 1996 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1995 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1994 : ¥4,300,000 (Direct Cost : ¥4,300,000)
New system for measuring the biological activity of micro-level particles, for example, planktonic and bacterial cells and their colony, in heterogeneous system was developed. This system, namaed LASMMA (Laser Semi-Microprobe Mass Analysis), is composed of YAG laser, infra-red microscope, quartz cell, gas purification line, and isotope ratio mass spectrometer (IRMS). This system was specialized for the ^<13>C-tracer experiment on phytoplanktonic photosynthesis.
Optical system, by which laser beam was applied to the sample through object lens of IR microscope, was prepared. Using TV camera, micro-spot was identified during laser treatment. Cellulose filter, of which isotope ratio was known, was treated with laser for 30 to 60 minutes. After purification and manometric measurement, the CO_2 was diluted with standard CO_2 gas of which ^<13>C content was known. The gas was introduced into IRMS to determine the ^<13>C content. Although the value of cellulose by LASMMA was lower than that by standard method, it suggested that its precision was enough for tracer experiment.
LSMMA method was applid in the field experiment. The ^<13>C uptake activity of Microcystis was etsimated in Lake Suwa. Colony of this alga was identified under microscope, and treated by laser. Its ^<13>C content increased from 1.09 atom% at the beginning of the experiment to 3.52 atom% after 24hr incubation. The ^<13>C content changed almost as same as that measured for particulate organic carbon (POC) by the usual way.It was confirmed that LASMMA method could be applicable for field tracer experiment. Moreover, it was suggested that LASMMA system might not be limited for tracer experiment, although the standard deviation measured was larger than usual way and the measurement took much time.
For future application, LASMMA System manual was rounded off.