Insitu bio-optical characteristics of several hard coral genera

Abstract

In situ bio-optic characteristics of corals were studied by examining spectral reflectance, absorbance, and irradiance, which applicable to improve further classification of corals from other type of reef benthics using remotely sensed satellite imagery. Corals are biological forming habitat (biotope) and geostructure created by corals can be clearly seen from space, thus constitute integral parts of dynamic coastal environment alongwith sand, seagrass, mud, rocks, and other types of substrate. The objective of this research was to study in situ bio-optical characteristics of several coral genera. Field data acquisition was performed on June 8 to 13, 2011 at Panggang Island and adjacent waters in the Seribu Islands. A total of 7 sampling stations and 65 samples of coral spectra were collected, comprising of spectral reflectance, irradiance, and absorbance. Bio-optic set data obtained were filtered prior to segregation at visible wavelength (400-750 nm) and curve-fitteddusing moving average method. Data analysis were as follows: curve pattern analysis, cluster analysis, discriminant analysis and spectral analysis at particular wavelengths. Results of this study showed that the patterns of reflectance, iradiansi, and absorbance of 18 hard coral genera were similar one another, yet there exist different magnitude response at particular bands of wavelength, as affected by coral colony pigmentcoloration (visually) and type of coral corallite. Further application of in situ biooptic may not differentiate coral species using satellite imagery, yet will be valid to separate living hard corals from other type of reef benthics (soft coral, rubble, etc).