Developing PSSdb: a Pelagic Size Structure database to support biogeochemical model development

Marine plankton are essential components of ocean ecosystems, forming the bottom of the food chain and serving as controls on large-scale biogeographic patterns in ocean carbon, nutrients, and oxygen. Earth System Model (ESM) projections suggest that ocean warming and stratification will drive decreases in net primary production (NPP) and shifts in plankton community composition and size structure. These changes to the plankton community have subsequent implications for decreasing the strength of the biological pump, as well as declining fisheries productivity through trophic amplification mechanisms. However, a critical underlying factor driving these shifts — the simulated size structure of plankton and particles — is difficult to validate, as global datasets are lacking. Fortunately, new data streams from plankton imaging systems are capable of providing 3-dimensional, broad-spectrum views on plankton and particle size spectra, provided data are properly harmonized and cross-calibrated to a single standard.
Following the structure of the World Ocean Database (WOD) and COPEPOD database, we propose to establish a methodological processing pipeline for the ingestion, calibration, and harmonization of imaging data on plankton and particles spanning five orders of magnitude (1 micron – 10 cm). The ultimate goal of our work is the development of the Pelagic Size Structure database, or PSSdb, as a resource for global gridded data. We will start off with data from five imaging systems that include in-situ samplers to tabletop imagers: Imaging FlowCytoBot (IFCB), FlowCam, Underwater Vision Profiler (UVP), ZooScan, and In-situ Ichthyoplankton Imaging System (ISIIS). The resultant data will be structured in four levels, ranging from low (level 1) to high (level 3) taxonomic resolution, and will be made publicly available through NOAA websites. Our methodological framework and resultant database will be broadly extensible, and able to incorporate both historical data and future sampling efforts. As plankton imaging systems become increasingly utilized in national and international sampling programs, and are being developed for automated vehicles, drifters, and floats, we anticipate both a growing need for data consolidation and harmonization, as well as the opportunity for these datasets to inform ESM development. Ultimately, an improved understanding of the key ecological mechanisms driving marine ecosystem shifts, elucidated by models with strong empirical validation, will increase confidence in Earth System Model projections and associated links between the climate and fisheries.