Award: OCE-1336206

Eelgrass meadows are shallow, coastal ecosystems found throughout the northern hemisphere that provide important ecosystem services including primary production, nutrient cycling, habitat for fisheries species, and erosion control. Considerable effort is aimed at conserving and restoring seagrass ecosystems to ensure the continued provision of these important ecosystem services. This project describes the second generation of a global collaborative research project, the Zostera Experimental Network (ZEN). In this project, we quantified geographic variation in the biological and physical processes structuring eelgrass ecosystems to advance our understanding of geographic variation in how a single community type functions, and to inform conservation and restoration strategies. More generally, the collaborative network built by this award exemplifies a team approach to doing science where collaboration across international boundaries embraces geographic variation in important ecological processes, and recognizes that only by understanding the causes of this variation can we fully understand how ecosystems function. Partners at 50 sites in 14 countries conducted parallel, standardized field sampling of the plants and animals at each site, as well as standardized measurement of important ecological processes such as herbivory and predation. From this we produced global maps of biodiversity (ranging from microbes to fish), biomass distribution among trophic levels, and ecosystem processes. We used these to describe for the first time how important structuring factors and processes such as predation, plant growth rates, and plant size vary with latitude and among ocean basins and coasts, and their conseauences at the ecosystem level. Partners at a subset of sites conducted experiments to characterize the interaction of forcing factors identified in surveys as potentially contributing to eelgrass ecosystem functioning. The replication of our sampling across four coasts in two ocean basins was a strength of the project, allowing us to disentangle the effects of latitude and geography from important mechanistic variables like ocean temperature and local biodiversity. Our experience suggests that ZEN has initiated a revolution in the field of seagrass ecology, making it more collaborative, more explicitly comparative, more comprehensive in its focus on microbes through top predators, and more focused on general ecological principles. Our program?s integrated characterization of biodiversity, ecosystem state variables, and process rates across the globe is arguably unique in any marine system. It builds on promising results from the first generation of ZEN to allow for the first time a rigorous analysis of links between biodiversity and ecosystem functioning in a natural system on a global scale. Our data on invertebrates and fishes and the consequences of their interactions for seagrasses provides a valuable and overdue complement to the many monitoring programs around the world that focus primarily on seagrasses themselves and water quality, and are being made publically available. The success of ZEN is evidenced by the growing number of partners in this global collaboration, and the fact that the network is taking on a life of its own independent of the PIs. Several new projects have been spawned as a result of ZEN work, many involving members outside the initial network and many of whom bring expertise from outside the world of marine ecology including genomics, microbiology, and disease dynamics. ZEN 2 also provided intensive training and international research experiences for 18 undergraduate interns who participated in a class at their home university and in remote class experiences with students from the other universities before embarking on research experiences across the globe. In addition, the project trained several graduate students at each university as well as a postdoctoral scholar. The network built by this grant has already outlived the duration of the grant itself and we see it as continuing to advance an innovative model of comparative-experimental research in global marine ecology. Last Modified: 02/05/2018 Submitted by: J. Emmett Duffy