Abstract: The global coral reefs are severely degraded by ocean acidification in recent years and satellite remote sensing can monitor coral reefs’ degradation timely. Due to the limitation of conducting acidification comparative experiments in the field, this paper proposes a method of measuring coral reef spectrum in the laboratory, which provides a new way for analyzing the influence of acidification on coral reefs by comparing the coral spectrum under different pH conditions. The experiments adopt three different acidities of 7.6, 7.9 and 8.1. And the results show the spectra of coral reefs have similar spectral shapes in general when the pH values are 8.1 and 7.9. When the pH is 7.9, the coral spectrum peak appears to move into the direction of long a wavelength. But when the pH is 7.6, there is an abnormal absorption valley between 650~700 nm in the coral spectrum, caused by the absorption of some algae. The results show that pH of 7.6 is a suitable acidity for the growth of some algae that can attach to the surface of coral reefs and affect the spectral properties of coral reefs.

Key words: ocean acidification, reef-building coral, spectral feature