Impact of Submesoscale Vertical Advection on Primary Productivity in the Southern East China Sea

Abstract

This study aims to investigate the impact of submesoscale vertical advection (SVA) on the primary productivity in the southern East China Sea. The analysis is based on a comparison between two numerical simulations by using a three‐dimensional coupled physical‐biogeochemical model. One simulation directly resolves SVA on a high‐resolution mesh, and the other leaves SVA unresolved on a low‐resolution mesh. The high‐resolution simulation outperforms the low‐resolution simulation in reproducing the observed chlorophyll distribution, particularly in summer. Resolving SVA results in an approximately 40% increase in primary productivity during the summer, though SVA activity is relatively weak in this season than in other seasons. Among multiscale physical processes, SVA, rather than mixing, is found to be the most important vertical nutrient supply pathway from the nutrient‐rich bottom water to the nutrient‐depleted surface water in summer, particularly on the middle and outer shelves. The impact of SVA on the shelf is unique compared to the open ocean in that it efficiently enhances vertical supply of nutrient‐rich subsurface waters to the nutrient‐depleted surface layer. This study highlights the importance of SVA in promoting primary productivity in stratified shelf seas.

Water Oxygen Consumption Rather Than Sediment Oxygen Consumption Drives the Variation of Hypoxia on the East China Sea Shelf

“…One reason to explain the discrepancy from the hypothesis might be attributed to the strong tidal current in the ECS, particularly on the Changjiang bank, which facilitates the resuspension of POC (Luo et al., 2017; Xuan et al., 2016). Furthermore, the energetic hydrodynamics sustain the transport of nutrients and POC (Meng et al., 2020; F. Zhou et al., 2020). This suggests that the specific hydrodynamic characteristics should also be taken into account when assessing the contribution of SOC versus WOC to hypoxia.…”

Distribution of Harmful Algae (Karenia spp.) in October 2021 Off Southeast Hokkaido, Japan

“…growth could have been superimposed on purely Lagrangian transport processes, and strong vertical advection induced by submesoscale variations could have contributed to the abrupt shelf-scale increase of Karenia spp. abundance (e.g., Meng et al, 2020). Further research will be needed to examine how small-scale submesoscale variations combined with algal growth contributed to the abrupt shelf-scale increase of Karenia spp.…”