Collaborative Research: Quantifying secondary production in complex tropical seascapes using ecosystem level manipulations

Secondary production, the process by which organisms build tissue by consuming primary producers (such as algae or plants), can be augmented by resources that are supplied from outside the ecosystem. This project advances understanding of the role of resource subsidies in secondary production in complex ecosystems, addressing a challenge that limits understanding of the carbon cycle. The team is constructing artificial reefs of different sizes, situated at different distances from mangroves, seagrass beds, and open ocean reefs. These will be used to test how proximity to these different sources of external subsidies and reef size interact to affect secondary production (growth of corals and fish). The project also supports research training for graduate and undergraduate students and public outreach through installation of information stands near project sites and production of an educational film for dissemination via a museum and social media platforms. The results of the project provide valuable information for artificial reef initiatives, important for coral reef restoration and for aquaculture, and are being shared with conservation organizations and resource managers. This project advances mechanistic understanding of how resource subsidies mediate secondary production in complex, open ecosystems. The team is carrying out an ecosystem-scale manipulative experiment, leveraging the high rates of secondary production of corals reefs. By constructing artificial patch reefs of different sizes that also vary in proximity to difference sources of subsidies, conducting sampling over a 4-year period, and using compound-specific stable isotope analyses to identify the origins of carbon in consumer tissues, the team are testing how 1) the supply rate of subsidies varies with proximity to mangrove, seagrass, or open ocean sources, 2) artificial reef size affects capacity to capture subsidies, and 3) capture capacity, supply rate, and supply type act independently and interactively to mediate production of corals and fish. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.