HR: 14:45h
AN: OS23H-04    [Abstracts]
TI: The Red Edge: Exploring high near-infrared reflectance of phytoplankton and submerged macrophytes and implications for aquatic remote sensing
AU: * Dierssen, H M
EM: heidi.dierssen@uconn.edu
AF: University of Connecticut, Department of Marine Sciences 1080 Shennecossett Road , Groton, CT 06340, United States
AU: Zimmerman, R C
EM: rzimmerm@odu.edu
AF: Old Dominion University, Department of Ocean, Earth and Atmospheric Sciences , Norfolk, VA 23529, United States
AU: Bissett, P J
EM: pbissett@flenvironmental.org
AF: Florida Environmental Research Institute, 10500 University Drive Suite 140, Tampa, FL 33612, United States
AB: Terrestrial vegetation and submerged macrophytes (seagrasses and seaweeds) exhibit strong reflectance in the near-infrared (NIR) portion of the electromagnetic spectrum (700-1600 nm). This NIR reflectance is commonly attributed to scattering from cell and leaf structures (cell walls and membranes, organelles, air spaces, etc.), and forms the basis of the terrestrial biomass parameter NDVI (normalized difference vegetation index). NIR reflectance is generally ignored for aquatic systems because water strongly absorbs infrared light. Here, we present laboratory measurements of visible and near infrared reflectance from a variety of phytoplankton cultures and in situ measurements of reflectance from different species of seagrass. Reflectance spectra from a variety of taxa Through reflectance measurements made on unpigmented and pigmented leaves, we hypothesize that photosynthetic pigments produce the red edge signature by absorbing visible, but not NIR, radiation. For dense suspensions of algal cells at the sea surface and submerged macrophytes, the infrared reflectance signal can be strong enough that it is not fully attenuated by the water, producing peaks in the reflectance spectra that are red-shifted relative to those produced by chlorophyll fluorescence. High resolution airborne imagery collected in conjunction with the California Center for Integrative Coastal Observations, Research and Education (CICORE) demonstrates elevated NIR reflectance apparent during intense surface algal blooms. The utility of the red edge signature for remote sensing applications in aquatic environments is discussed.
DE: 4217 Coastal processes
DE: 4275 Remote sensing and electromagnetic processes (0689, 2487, 3285, 4455, 6934)
DE: 4546 Nearshore processes
DE: 4805 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4912)
DE: 4815 Ecosystems, structure, dynamics, and modeling (0439)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly