Day 1-2 (2023/4/19-2023/4/20)
We arrived at Kagoshima on the evening of
4/19, and went to Kikai Island to start the water sample collection on the
morning of 4/20.
We collected water samples from 12 sites for
the 14C, 18O, and Uranium measurement. At the same time,
we measured the temperature, conductivity, pH, and calcium ion concentration of
the water sample.
In the afternoon, we had to stop sampling due
to the heavy rain, but we set up a rainwater collection bottle in the Wan area.
Day 3 (2023/4/21)
In the morning, we collected about 50 mL of rainwater from yesterday's rain, then we went to the Kikai Island Agricultural and Water Conservancy Institute (喜界島農業水利事業所). Prof. Yokoyama explained the results of Tsujino-san's previous research about groundwater in Kikai. Then, the staffs led us to the school lecture hall where the core samples were stored and displayed the location of the core collection sites.
Due to the large number of cores, we checked
the samples from only some of the collection sites, marked the location of the
corals in the core, and took photos of the cores. 14C dating of
these corals can help determine the year of the core. However, due to time
constraints, we did not collect coral samples right away.
In the afternoon, we went to the Kikai Town
Hall (喜界町役場).
Prof. Yokoyama introduced our research to the local government staff, and then we
discussed the method of collecting tree samples from a tree with about 300
years age. This tree was cut into three sections horizontally and then
transported to the Kikai Town Hall for assembly and fixation. According to the
cross-section figure, we attempted to collect samples from the main trunk of
the middle section, but due to the difficulty in pulling out the middle section
in a short period of time, we chose to firstly take some samples from the top
three branches, from the center of the tree ring to the edge, and also
contacted local staff to assist us in our future middle section sampling plan.
Day 4 (2023/4/22)
In the morning, after collecting water samples
from three sites, due to heavy rainfall, we moved indoors and collected coral
samples from the core we checked on 4/21. After the weather became better, we
continued sampling the water samples. Parameters such as temperature,
conductivity, pH, and calcium ion concentration are also measured.
Due to the strong wind and wavy sea, it took some time for collecting water samples from the seaside.
The following photos show some of our sampling
sites.
In summary, this trip collected water samples
from a total of 24 sites for 14C, 18O, and Uranium analysis
and measured the water parameters on site. 9 coral samples and tree ring samples
from 3 branches were also collected.
