Influence of Marine Heatwaves on Upwelling Parameter in Indonesian Fisheries Management Area (IFMA) 713 Waters

Abstract

Abstract An upwelling process linked to water productivity is likely to be affected by marine heatwaves (MHWs). The events of MHWs are distinguished by warmer sea surface temperature (SST), leading to increased stratification, causing vertical mixing limits and suppressing the upwelling process. In the Indonesian Fisheries Management Area (IFMA) 713 waters, which have enormous potential for fishery resources, five upwelling areas were identified during the southeast monsoon months (May–October) based on the Ekman pumping velocity (EPV) assessment, namely locations A (western part of West Sulawesi), B (southern Makassar), C (eastern part of Bone Bay), D (southern Banjarmasin), and E (southern Makassar Strait). Thus, this study aimed to investigate the influence of MHWs on upwelling parameter (chlorophyll-a concentration) in IFMA 713, particularly in 1998 and 2016, where prominent MHWs occurred and coincided with upwelling sessions. To accomplish this, EPV anomalies and chlorophyll-a concentrations for each MHWs event during May–October 1998 and 2016 were calculated. The analysis revealed that MHWs events co-occuring with negative (upwelling velocity is weaker than the climatological mean) and positive (upwelling velocity is stronger than the climatological average) EPV anomalies were associated with decreased chlorophyll-a concentrations.