Potential predictability of marine ecosystem drivers

Climate variations can have profound impacts on marine ecosystems and the socio-economic systems that may depend upon them. Temperature, pH, oxygen (O₂) and net primary production (NPP) are commonly considered to be important marine ecosystem drivers, but the potential predictability of these drivers is largely unknown. Here, we use a comprehensive Earth system model within a perfect modelling framework to show that all four ecosystem drivers are potentially predictable on global scales and at the surface up to 3 years in advance. However, there are distinct regional differences in the potential predictability of these drivers. Maximum potential predictability of more than 10 years is found at surface for temperature and O₂ in the Southern Ocean and for temperature, O₂ and pH in the North Atlantic tied to ocean overturning structures with ‘memory’ or inertia with enhanced predictability in winter, as well as in the Arctic Ocean at surface. In contrast, minimum predictability is simulated for NPP (<1 years) in the high latitudes, potentially liked to variations in cloud cover and thereby limitations to radiation available for photosynthesis under storm tracks. Potential predictability for temperature, O₂ and pH increases with depth to more than 10 years below the thermocline, except in the tropical Pacific and Indian Ocean, where predictability is also three to five years on subsurface levels. This study indicating multi-year (at surface) and decadal (subsurface) potential predictability for multiple ecosystem drivers is intended as a foundation to foster broader community efforts in developing new predictions of marine ecosystem drivers.