Impact of El Niño and La Niña on the ocean carbon cycle

MBT Marine Biotechnology, Xiamen University Malaysia, 999004 Sarat Tinggi, Sepang District, Selangor, Malaysia

^* Corresponding author: MBT2309461@xmu.edu.my

Abstract

This study investigates the impacts of El Niño and La Niña on the ocean carbon cycle, focusing on how these events influence CO₂ exchange, the biological pump, and carbon sequestration across ocean regions. The ocean carbon cycle plays a pivotal role in the global carbon balance, and its dynamics are significantly affected by El Niño and La Niña phenomena, which alter sea surface temperatures, upwelling processes, and nutrient supply. During El Niño events, reduced upwelling and increased sea surface temperatures cause the eastern Pacific to shift from a carbon sink to a carbon source, releasing significant amounts of carbon into the atmosphere. Conversely, La Niña events promote stronger upwelling, increased nutrient delivery, and enhanced CO₂ uptake by oceans, but they also lead to ocean acidification due to the upwelling of CO₂-rich waters. The study emphasizes the need for broader observational coverage and refined models to accurately simulate ENSO impacts on carbon cycling, particularly in the Indian Ocean and Southern Hemisphere. Future research should focus on extending observational networks, improving model representation of biogeochemical processes, and integrating ENSO-driven carbon flux variability into global climate models and national carbon inventories. This research contributes to the understanding of how ENSO influences global carbon balances and supports efforts to mitigate climate change impacts, in line with the Paris Agreement’s carbon neutrality goals.