著者

久米 智也 瀬名波 出 依田 欣文

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会九州支部講演論文集

巻号頁・発行日

vol.2019, 2019

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<p>The influence of photosynthesis on the growth of red algae <i>Agardhiella subulata</i> was investigated. First, changes in photosynthetic activity due to the amount of light irradiated on algae and changes in photosynthetic activity due to addition of CO₂ were tested under a total of 6 conditions including a seawater temperature of 25 °C, light intensity of 75, 150, 250 μmol/(m²·s) and CO₂ addition amount of 0, 15 mg/L. Next, the change in photosynthetic activity by seawater temperature was tested in total 3 conditions including CO₂ not added, light intensity of 150 μmol/(m²·s), seawater temperature of 20, 25, 30 °C. Measurement of the maximum quantum yield <i>F</i>v/<i>F</i>m, which is an indicator of photosynthetic activity, uses chlorophyll fluorescence measurement PAM. <i>F</i>v/<i>F</i>m with the continuous light period <i>L</i>24 h, CO₂ not added, the light intensity of 75 μmol/(m²·s) was the highest, and <i>F</i>v/<i>F</i>m decreased in a short time as the photon quantity increased. The maximum slope was 0.55 at sea water temperature of 25 °C and 30 °C, but the maximum value was 0.44 at 20 °C. In the continuous dark period <i>D</i> 24 h, <i>F</i>v/<i>F</i>m increased by about 0.10 at <i>D</i> 9 h regardless of the number of photons when CO₂ was not added and increased by about 0.10 at <i>D</i> 3 h at a CO₂ addition amount of 15 mg/L. <i>F</i>v/<i>F</i>m is an indicator of photosynthetic activity. It is thought that maintaining this high will lead to the growth of algae. Experimental results show that <i>F</i>v/<i>F</i>m is maintained high by setting the light period to 12 h and the dark period to 3 to 6 h. It was also shown that <i>F</i>v/<i>F</i>m is also affected by the photon quantity and CO₂. From the above it is considered that growth of seaweed can be expected by balancing the light period and the dark period.</p>