Priority conservation areas based on plankton particle trajectories as an alternative to marine protected areas

Ecological modelling has enhanced our understanding of ecosystems and biodiversity, and it has been widely used in policy decision-making. Strengthening our ability to represent ecosystems and their interactions with human activities is a global priority for achieving conservation goals. However, most existing spatial conservation frameworks rely on staticMarine Protected Areas (MPAs), defined by fixed geographic boundaries and invariant management rules that do not account for the strong temporal variability, circulation-driven connectivity, and climate-induced shifts that characterize marine ecosystems. As a result, static MPAs may fail to consistently protect key ecological processes, particularly in pelagic systems where biological organization is shaped by moving water masses. One way to address this is through the design and implementation of “dynamic” Marine Protected Areas (dMPAs) - areas that shift in space and time based on plankton trajectories, given their ecological importance. The recognition of the importance of marine plankton for human well-being has sparked proposals to prioritize plankton in marine policymaking. Yet scientific investigation into defining species-based areas has not been undertaken, despite their fundamental role in sustaining the oceans and marine life. Our research demonstrates the value of adopting dynamic approaches for conserving marine ecosystems, which are highly variable and interconnected by ocean circulation. Using a Lagrangian particle-tracking framework implemented with OceanParcels, we simulate the transport, retention, and aggregation of planktonic communities by integrating hydrodynamic fields with plankton distribution models. From these simulations, we identify spatiotemporal hotspots of particle aggregation and retention, interpreted as regions of enhanced ecological significance, which we define as Plankton Priority Areas for Conservation (PPACs). By comparing aggregation patterns across winter, spring, summer, and autumn, we identify both seasonal hotspots and areas of persistent retention. To place PPACs in a broader conservation context, we assess their overlap with four complementary indicators - biodiversity distribution, climate resilience, carbon sequestration potential, and ecosystem vulnerability. Our results demonstrate that dynamic, circulation-informed conservation areas can reveal ecologically critical regions that are poorly represented by static MPAs and provide a flexible, scalable complement to existing conservation tools in a changing ocean.