A Global Plankton Diversity Monitoring Program

Planktonare the base of marine food webs, essential to sustaining fisheriesand other marine life. Continuous Plankton Recorders(CPRs) have sampled planktonfor decades in both hemispheres and several regional seas. CPR research has been integral to advancing understanding of planktondynamics and informing policyand management decisions. We describe how the CPR can contribute to global planktondiversity monitoring, being cost-effective over large scales and providing taxonomically resolved data. At OceanObs09 an integrated network of regional CPR surveys was envisaged and in 2011 the existing surveys formed the Global Alliance of CPR Surveys (GACS). GAGS first focused on strengthening the dataset by identifying and documenting CPR best practices, delivering training workshops, and developing an integrated database. This resulted in the initiation of new surveys and manuals that enable regional surveys to be standardized and integrated. GACS is not yet global, but it could be expanded into the remaining oceans; tropical and Arctic regions are a priority for survey expansion. The capacity building groundwork is done, but funding is required to implement the GACS vision of a global planktonsampling program that supports decision-making for the scientific and policy communities. A key step is an analysis to optimize the global sampling design. Further developments include expanding the CPR for multidisciplinary measurements via additional sensors, thus maximizing the ship-of-opportunity platform. For example, defining pelagic ecoregionsbased on planktonand ancillary datacould support high seas Marine Protected Areadesign. Fulfillment of Aichi Target 15, the United Nation's Sustainable Development Goals, and delivering the Essential Ocean Variables and Essential Biodiversity Variables that the Global Ocean Observing Systemand Group on Earth Observation's Biodiversity Observation Network have, respectively, defined requires the taxonomic resolution, spatial scale and time-series data that the CPR approach provides. Synergies with global networksexploiting satellite data and other planktonsensors could be explored, realizing the Survey's capacity to validate earth observation data and to ground-truth emerging planktonobserving platforms. This is required for a fully integrated ocean observing systemthat can understand global ocean dynamicsto inform sustainable marine decision-making.