EGU23-990, updated on 27 May 2024
https://doi.org/10.5194/egusphere-egu23-990
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Dust fertilization: Measurements of CO2 sequestration by coral reefs in the Gulf of Eilat, Israel after atmospheric dust loading.

Hamish McGowan1, Nadav Lensky2, Shai Abir2,3, Yonathan Shaked3,4, and Eyal Wurgaft5
Hamish McGowan et al.
  • 1The University of Queensland, Australia (h.mcgowan@uq.edu.au)
  • 2Geological Survey of Israel, Jerusalem, Israel.
  • 3Hebrew University of Jerusalem, Jerusalem, Israel.
  • 4Interuniversity Institute for Marine Sciences, Eilat, Israel.
  • 5The Avinoam Adam Dept. of Natural Sciences, The Open University of Israel, Ra'anana, Israel.

Coral reefs are complex biophysical, geochemical and hydrodynamic marine environments impacted by meteorological processes. In continental coastal and oceanic locations bordering or downwind of dust source areas, coral reefs are affected by the deposition of dust. Dust may supply nanomolar amounts of nitrate and essential bio-elements including iron, manganese, zinc and copper from natural, industrial and agricultural processes to coral reefs; in turn these are absorbed by the coral algae symbionts, thereby enhancing chlorophyll concentrations. This fertilization of coral reefs by dust increases photosynthesis which lowers the aqueous CO2 partial pressure relative to the overlying air. If this causes a reversal of the coral reef water to air CO2 gradient, then a coral reef will switch from a source to sink of CO2.

Here we present the first direct measurements of air-sea CO2 exchange measured by an eddy covariance tower exclusively over the fringing coral reefs in the Gulf of Eilat, Israel. These show a strong relationship to atmospheric dust load entrained from the surrounding hyper-arid deserts in Israel, Saudi Arabia and North Africa. The coral reefs became CO2 sinks most notably during episodes of moderate to high atmospheric dust load. We conclude that the coral reefs in the Gulf of Eilat are net sinks of atmospheric CO2 due to the deposition of dust and suggest that direct measurements of air – sea CO2 exchange are required over coral reefs in other locations impacted by dust to increase accuracy of marine and global carbon budgets.          

How to cite: McGowan, H., Lensky, N., Abir, S., Shaked, Y., and Wurgaft, E.: Dust fertilization: Measurements of CO2 sequestration by coral reefs in the Gulf of Eilat, Israel after atmospheric dust loading., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-990, https://doi.org/10.5194/egusphere-egu23-990, 2023.