63 / 2024-09-04 16:00:34

Marine phytoplankton responses to typhoon events with different tracks in the Pearl River Estuary based on numerical simulation

Marine biogeochemistry,Typhoon response,Pearl River Estuary,Numerical simulation,Hydrodynamic-Ecological Model

Session 6 - Tropical Cyclone-Ocean Interactions: From Weather to Climate Scales

Typhoons can trigger complex marine biogeochemical reactions. This study, utilizing the Carbon, Silicate, and Nitrogen Ecosystem (CoSiNE) model, coupled with the unstructured grid, Semi-Implicit Cross-scale Hydroscience Integrated System Model (SCHISM), examines and categorizes the biogeochemical responses caused by typhoons passing through the Pearl River Estuary (PRE) from 2012 to 2022. The results reveal significant differences in the ocean response induced by two different types of typhoons: the east-side landing typhoon and the west-side landing typhoon. The different wind stresses associated with these typhoons lead to varied dynamic conditions in the estuary. Compared to the west-side landing typhoon, the east-side landing typhoon is more conducive to the spread of nutrients from the bay to the open sea, thereby promoting the proliferation of phytoplankton. Simulated results of phytoplankton nitrogen uptake distribution indicate that the abnormal changes in chlorophyll-a (Chla) outside the bay are primarily not driven by biological processes. The environmental variable changes during east-landing typhoons demonstrate that the marine environment responses to typhoons significantly vary according to the different typhoon paths. The differences in coastal water responses to typhoons result from the combined effects of typhoon movement path, intensity, and runoff changes, primarily attributed to the typhoon events’ overall influence on the distribution of the Pearl River diluted water and the ecological processes associated with the plume. This study provides new insights into the mechanisms of biogeochemical effects of typhoon events on the PRE, enhances the understanding of coastal ecological responses to typhoons, and aids in predicting ecological environment changes in the PRE during typhoon events.