| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2022: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2021: ¥800,000 (Direct Cost: ¥800,000)
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| Outline of Research at the Start |
Phytoplankton-bacteria interactions are critical in enhancing nutrient recycling and the interactive effects could be applied for enhancing microalgal productivity. However, previous work has been less focused on how nutrients circulate among water, phytoplankton, and the bacterial community and how it relates to phytoplankton stoichiometry.The present research fills this gap by conducting experiments using molecular and stoichiometric analyses.We hope to provide new insights into bacterially-mediated phytoplankton stoichiometry and related aquatic ecosystem functioning.
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| Outline of Annual Research Achievements |
In the present study, the growth rate hypothesis (GRH) was demonstrated to be inapplicable for Chlorella vulgaris, a type of green algae, under N starvation. In fact, the research showed that under low nutrient levels, the organism had a higher requirement for nitrogen than phosphorus. This suggests that the causality of nitrogen, protein, and biomass under phosphorus starvation may be different from what was previously assumed. Our results indicated that N, rather than P, would be the primary element limiting phytoplankton growth under low-nutrient conditions. If this phenomenon is applicable for all phytoplankton species, it could be valid for controlling phytoplankton biomass in aquatic ecosystems, and could improve biomass management of blooming phytoplankton by emphasizing a specific nutrient.
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