In a first-of-its-kind discovery, an international study led by The University of Queensland has disproved the long-held theory that coral reefs only have the capacity to emit CO2.
The study compared data from Heron Reef on the Great Barrier Reef, and the Middle East’s Gulf of Aqaba, and found that dust blown in from nearby deserts can convert coral reefs into CO2 sinks.
Professor Hamish McGowan from UQ’s School of Earth and Environmental Sciences said the discovery was made after researchers observed a correlation between influxes of CO2 and periods of increased dust concentrations in the atmosphere around the reefs.
“We were surprised at how significant a role dust accumulation played in switching coral reefs from a CO2 source to a CO2 sink,” Professor McGowan said. “This process was previously thought to be impossible, but our research proves otherwise.
“We found that the build-up of dust in the traditionally low-nutrient and low-chlorophyll waters of the Gulf of Aqaba actually fertilizes and improves coral-growing conditions and photosynthesis in reef ecosystems.”
Professor Nadav Lensky from Geological Survey Israel said these improved conditions mean desert reefs have the potential to act as a place of refuge for coral.”In this study we also measured extreme evaporation rates over the coral reefs in the Gulf of Aqaba, at the most northern tip of the Red Sea,” Professor Lensky said. “This process consumes large amounts of heat and keeps water temperatures typically below the threshold that causes coral bleaching.
More information: Hamish McGowan et al, Direct Measurement of CO 2 Air‐Sea Exchange Over a Desert Fringing Coral Reef, Gulf of Eilat (Aqaba), Israel, Journal of Geophysical Research: Oceans (2022). DOI: 10.1029/2022JC018548
