Research brief: Do aerosols produced by coral reefs influence climate?

Coral reefs are known to produce a chemical called dimethyl sulfide (DMS), which, when released into the atmosphere, can help form or grow tiny particles known as aerosols. Currently, this source of aerosols produced by coral reefs is unaccounted for in climate science and hence the impact of coral reef extinction on aerosols and climate is unknown.

Picture: Coral reef. Credit: Francesco Ungaro (Pexels).

Coral reefs are known to produce a chemical called dimethyl sulfide (DMS), which, when released into the atmosphere, can help form or grow tiny particles known as aerosols. Large numbers of aerosols can reduce the amount of sunlight reaching the ground (think back to days of significant bushfire smoke). Alternately, aerosols are essential in cloud formation, and changing their number or size can change cloud characteristics and even influence rainfall.

Currently, this source of aerosols produced by coral reefs is unaccounted for in climate science and hence the impact of coral reef extinction on aerosols and climate is unknown. In this study, we address this problem for the first time by using a climate model that can simulate the complex chemistry, aerosol and cloud processes described above. We find that the extinction of coral reefs could lead to small decreases in the number and size of aerosols. However, these decreases are found to be too small to influence how much sunlight reaches the ground or to change cloud properties.

Paper: Fiddes, S. L., Woodhouse, M. T., Lane, T. P., and Schofield, R.: Coral reef-derived dimethyl sulfide and the climatic impact of the loss of coral reefs, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2020-1054, in review, 2020.