Exploring contribution of phytoplankton cell death to settleable particulate organic carbon in the East China Sea in...

Phytoplankton's death contributes to marine settleable particulate organic matter (POM). In this study, we used laboratory cultivation of different algal species to identify a positive correlation between the cumulative number of dead algal cells and POC_>75 (carbon content of the settleable POM). The contribution coefficient of cell death to POC_>75 varied among different algal species. Additionally, the field survey and incubation experiment were conducted in the East China Sea (ECS) to explore the spatial-temporal correlation between phytoplankton death and POC_>75. The results concluded that phytoplankton death was the main factor controlling POC_>75. In the ECS, the relationship between the surface cumulative mass of POC_>75 and the cumulative number of dead cells followed: Cumulative mass of POC_>75(mg) = 0.487 × Cumulative number of dead cells (/10⁴) + 0.069. This study provided a methodology to quantitatively explain the relationship between phytoplankton death and settleable POM.