also explore the
issue of floating vegetation, but focus on nearshore areas where
seagrass wrack contributes a large part of the floating material. Based
on spectral measurements of Sargassum and the seagrass Syringodium
filiforme, both in laboratory mesocosms and from the air using the
Portable Remote Imaging Spectrometer, the authors find that a simple
“Sargassum Index” of reflectance at 650 and 630 nm can discriminate
between the two vegetation types. Age of the wrack could be estimated
based on its water absorption feature at 930–990 nm. The authors
conclude that hyperspectral imagery is necessary to simultaneously
discriminate among floating vegetation and to assess its age. Because
wrack typically organized in windrows with 5–35 m spacing, HyspIRI
offers good spectral and spatial capability to study nearshore floating
vegetation.