Rapid identification of source material levels in coral sand ornithogenic sediments by reflectance spectroscopy

Ornithogenic sediments are ideal materials for studying past eco-environmental changes. We collected sediment cores from Xisha archipelago of the South China Sea. The relative ratios of source materials (plant, guano and coral sand) of such sediments from Guangjin, Jinqing, Jinyin and Ganquan Islands in the Xisha archipelago, were reconstructed by reflectance spectroscopy. The consistence between the results obtained from reflectance spectroscopy and those obtained from traditional chemical analysis suggests that reflectance spectroscopy can be an ideal indicator for source material levels in the ornithogenic coral sand sediments. The possible implications of changes in source materials from the bottom toward top of the sediment cores are also discussed in our study. Seabird activities appear central to the ecological development of these island ecosystems.