Project: Collaborative Research: EAGER: Solving Darwins paradox: combining emerging technologies to quantify energy fluxes on coral reefs

NSF abstract:
Coral reefs are among the most diverse and productive ecosystems, but they are located in nutrient-poor tropical oceans that are ill-suited to sustain their iconic abundance. This paradox has puzzled scientists for centuries. While several organisms have been suggested to support life on reefs, when, where, or why they emerge as critical players for coral reefs is largely unknown. This project examines how the characteristics of a coral reef shape its reliance on different organisms to sustain all the large fishes typically associated with reefs. By quantifying fine-scale features of small reef patches, such as their temperature, wave energy, architecture, and small, hidden species assemblages, and combining these findings with a detailed analysis of what large fishes residing on the reef have eaten over time, this research reveals the circumstances under which different coral reef organisms – from minute algae to corals, plankton, sponges, microscopic invertebrates, or tiny fishes – take on important roles in feeding larger fishes. Using aerial drone surveys to scale up these fine-scale patterns to the area of an entire reef, the project then provides a whole-reef estimate for the contributions of different organisms to life on a reef. In doing so, the research offers a new opportunity for coral reef stewardship: if the most important organisms for coral reef productivity can be identified reliably from a few features, a much more targeted, context-specific management framework is possible. Finally, the project yields training opportunities for young, emerging reef scientists from coral reef nations, and a plethora of attractive digital coral reef media to engage the general public and increase awareness of the fragility of coral reef ecosystems.

The movement and storage of energy underpins the functioning of all ecosystems on Earth. The extreme diversity and productivity of coral reefs, despite their location in oligotrophic waters, has long generated substantial interest in the role of different organisms for coral reef energy fluxes. Yet, to date, these findings appear to be highly context-specific, and no general understanding exists concerning the environmental, structural, or biological drivers that cause reliance on one or more sources or pathways of productivity on coral reefs. As the first project to combine underwater data loggers, structure-from-motion photogrammetry, biological collections, underwater stereo-video, and compound-specific isotope analyses of amino acids, this research investigates how various interdependent attributes of small reef patches–such as wave exposure, rugosity, and cryptobenthic community structure–affect the relative contributions of different organisms to coral reef energy fluxes. By integrating the resulting relationships with aerial drone surveys and an exploration procedure based on quantitative color pattern analyses, the research then scales up the uncovered patch-dynamics to the area of an entire reef, ultimately revealing the contributions of different sources and pathways to reef fish biomass at the scale of the ecosystem. This reveals the potential pathways that can sustain coral reefs and their environmental and structural drivers. In doing so, the project offers a more general solution to a centuries-old question, while providing a new lens through which coral reefs can be managed in the Anthropocene.

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.