Expectations for the future

　This study has shown that a method for quantifying faecal pallets of zooplankton using a fine-mesh plankton net and an imaging scanner is effective. This method can reveal day-night differences in the abundance and size of faecal pallets, which could not be determined by conventional sediment traps because they require a 2 to 3 days moored sampling period. Zooplankton faecal pallets are not only an important driver of the material cycle in the ocean, but also serve as a food resource for zooplankton in the field, especially in the deep sea. The fact that there is a clear diurnal difference in the amount and size of zooplankton faecal pallets is expected to have a significant impact on the ecology of deep-sea organisms that feed on them, and is a technique that is expected to be applied in future deep-sea biological research.

　The results of this research will make it possible to more accurately quantify the amount of faecal pallets of zooplankton in the ocean, which is expected to lead to an accurate quantitative evaluation of the material cycle in the ocean, which has a significant impact on global environmental change.