10:00–10:15 | ABSTRACT 1091
WARMING-DRIVEN VERTICAL REORGANISATION OF OCEAN PRODUCTIVITY: THREE DECADES OF INCREASING SUBSURFACE NPP AT HOT AND BATS
Net primary production (NPP) underpins the biological carbon pump and is a key indicator of ocean ecosystem health, yet its long-term trajectory remains unresolved. Satellite records indicate a global decline, while Earth System Models show weaker or even opposing trends. A critical but underexplored driver of this discrepancy is the vertical structure of production: as ocean warming and increasingly frequent marine heatwaves strengthen stratification, surface and subsurface phytoplankton communities respond differently to changing light and nutrient availability, generating contrasting NPP trends with depth that surface-based satellite algorithms cannot capture. Here, we integrate multi-decade in situ records from the Hawaii Ocean Time-series (HOT) and the Bermuda Atlantic Time-series Study (BATS) with satellite observations (CbPM, VGPM, CAFE) and CMIP6 Earth System Model output to assess how NPP has been changing through the water column as sea surface temperatures rise. At both stations, in situ data reveal that subsurface NPP has increased in the last three decades, while surface NPP has remained flat or declined. This pattern is reproduced by CMIP6 models but missed by satellite algorithms, which show the opposite integrated trend. These findings suggest that conventional surface-based metrics mask a long-term vertical reorganisation of ocean productivity, with important consequences for monitoring ecosystem responses and predicting carbon cycle feedbacks under climate change.
Clara Rodriguez Vives, GESTAR II, NASA Goddard Space Flight Center, [email protected], https://orcid.org/0000-0002-6150-7644
Hanani Adiwira, WPI-AIMEC, Tohoku University, Sendai, Japan, [email protected]
Hakase Hayashida, JAMSTEC, Yokohama, Japan, [email protected]
Christina Schallenberg, CSIRO, Hobart, Australia, [email protected]
