Effects of suspended matter concentration in water body on the spectral reflectivity of submersed plant Hydrilla verticillata

To restore submersed aquatic vegetation has been recognized as an effective measure in improving eutrophicated water bodies and reestablishing aquatic ecosystems. Remote sensing technology can be used to timely monitor the distribution and growth status of submersed vegetation on a large scale, but the suspended matter in water bodies may affect the spectral characters of submersed vegetation, resulting in an inaccuracy of the interpretation of related remote sensing images. In this study, the spectral reflectivity of submersed plant Hydrilla verticillata in the water bodies with different suspended matter concentration was measured by a ground FieldSpec Pro JR spectroradiometer, and the results showed that the spectral reflectivity of the submersed plant increased with increasing concentration of suspended matter at the band of 400-900 nm. Significant correlations were observed between the suspended matter concentration and the spectral reflectivity of H. verticillata community at the band of 400 - 900 nm (P < 0.05) and of 450 - 900 nm (P < 0.01), and a clear linear relationship was found at the wavelength bands of blue, green, red and NIR. The results obtained in this study could be used to calibrate the effects of suspended matter in water body on the spectral reflectivity of submersed vegetation, and be helpful to rapidly and accurately monitor the distribution and dynamics of submersed vegetation on a large scale with remote sensing.