文献类型：期刊文献

英文题名：Rethinking the Impact of Marine Heatwaves on Phytoplankton Chlorophyll-A in the South China Sea

作者：Chen, Yingjun[1]; Shen, Chunyan[2]; Zhao, Hui[1,3,4]

机构：[1] College of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang, 524088, China; [2] College of Fisheries, Guangdong Ocean University, Zhanjiang, 524088, China; [3] Cooperative Research Center for Offshore Marine Environmental Change, Guangdong Ocean University, Zhanjiang, 524088, China; [4] Southern Marine Science and Engineering Guangdong Laboratory [Zhuhai], Zhuhai, 519082, China

年份：2024

外文期刊名：SSRN

收录：EI(收录号：20240108808)

语种：英文

外文关键词：Chlorophyll - Ecosystems - Offshore oil well production - Phytoplankton - Surface waters - Turbidity

外文摘要：Marine heatwaves (MHWs) in tropical oceans significantly suppress phytoplankton chlorophyll-a concentration (Chla) according to historical studies. However, pre-MHW Chla is rarely considered as the reference value in previous research approaches. In this paper, we propose an improved method to re-explore the impact of MHWs on Chla from 1998 to 2022 in the South China Sea, and the response of Chla to MHWs in different regions is further discussed according to the variation characteristics of Chla during MHWs. The results show that the response of Chla to MHWs exhibits regional variability. Interestingly, there is a large proportion of positive Chla anomalies (~0.55) in both the estuary and offshore regions during MHWs, however, the Chla anomalies are mostly negative in the upwelling regions. These different response patterns are related to background conditions, including nutrient concentration and turbidity, which regulate nutrient availability, light, as well as water column stability, leading to prominent changes in phytoplankton biomass. In upwelling regions, MHWs weaken the intensity of the upwelling and inhibit the uplift of nutrient-rich water from the deep to the sea surface, thereby decreasing Chla. Nevertheless, in nutrient-rich estuaries with high turbidity and light limitation, MHWs weaken the vertical supply of nutrients, but Chla increases. This surprising result can be due to the MHWs-induced water column stratification, which increases the transparency of water bodies and promotes phytoplankton retention in the surface layer, leading to an improvement of light availability and in turn an increase in phytoplankton biomass. Furthermore, increased atmospheric wet deposition brings nutrient inputs, as indicated by the total precipitation anomalies during MHWs, which can stimulate phytoplankton growth by providing abundant nutrients in the oligotrophic offshore region. These results have improved our understanding of the impact of MHWs on marine ecosystems. ? 2024, The Authors. All rights reserved.