Award: OCE-1737399

Many of the world's most abundant fisheries occur in upwelling-intensive, mid-latitude environments, and it is thought that these populations are largely sustained by bottom-up (i.e., nutrient-driven) trophic food webs fueled by new primary production from upwelled nutrients. Eastern boundary currents such as the California Current are among the most productive marine ecosystems on the planet and support a significant proportion of global fisheries, yet there are unanswered questions about the role of mesozooplankton (0.2-20 mm in size; includes larval fishes and gelatinous organisms) in transferring this production through upwelling food webs. Regional and global shifts in major currents, including upwelling strength, together with temperature-induced latitudinal shifts in species ranges that are already occurring and predicted to continue will have major effects on interactions among species, and consequently, food webs. Understanding these interactions and predicting future changes is highly relevant to science, society, and economies. During this study, researchers sampled the winter and summer seasons in the northern California Current off central Oregon (intermittent upwelling) and northern California (continuous upwelling) with the high resolution In Situ Ichthyoplankton Imaging System to obtain an accurate description of mesozooplankton communities: their abundances, and horizontal and vertical spatial distributions, over contrasting upwelling/downwelling system dynamics. In parallel, they collected depth-discrete mesozooplankton samples to quantify seasonal diets for larval fishes and gelatinous zooplankton and prey-specific growth rates of larval fishes. The researchers used fish ear stones (otoliths) of ecologically important fishes such as northern anchovy, lantern fish (Myctophidae), and rockfish (Sebastes spp.) to examine variation in daily growth and its relationship to oceanographic conditions as well as the abundance of larval fish prey and predators. To examine the role of zooplankton prey and predators in the food web, researchers examined the gut contents of particular taxa and applied stable isotope analysis. They also experimentally examined the foraging behaviors of gelatinous zooplankton, including a massive bloom of pyrosomes that followed a marine heatwave in the eastern Pacific Ocean. This project trained more than 20 undergraduates, five graduate students, and two post-doctoral scholars. Additional technicians, researchers, journalists, and high school teachers participated in the cruises, and K-12 students were exposed to multiple aspects of the research. The study included the participation of four (one per cruise) professional Artists-at-Sea in a collaborative residency program with the Sitka Center for Art and Ecology. Artwork by these artists, as well as photographs narrating the project, and an open call for ocean-themed art from the community were exhibited in a month-long public show, From Drifters to Swimmers. Plankton imagery from this project was used to build the Global Plankton Imagery Library, an open-access repository for plankton imagery that is a key resource for the research community. The researchers also added imagery from the study to Plankton Portal, a public website they developed in partnership with the Citizen Science Alliance's Zooniverse, that invites citizen scientists to participate in classifying plankton from field photographs. Collaborative participation by two NOAA senior scientists helped to set the broader context for two years of field data collected during the study and enable cross-program comparisons of data. Incorporation of the plankton imagery data into the long-term time-series of monitoring enables the data to be maximally useful in evaluating changing ocean conditions now and into the future. Last Modified: 11/02/2021 Submitted by: Su Sponaugle