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Abstract Detail

Physiological Section

Thorhaug, Anitra [1], Berlyn, Graeme [2], Poulos, Helen [3].

Remote sensing seagrass mapping:The spectral physiological responses to blue and green vs. white diminishing light on 4 seagrass species: Thalassia testudinum, Zostera marina,Halodule wrightii, Syringodium filiforme.

The worldwide seagrass population is declining at ever accelerating rates, estimated to be 7% presently despite conservation efforts worldwide. Remote sensing mapping of seagrasses will shortly be as vital for seagrass stewardship as remote sensing is presently for forests. One critical problem of present seagrass remote measurements concerns low levels of physiological spectral responses information for seagrass to major natural and anthropogenic changes. We have previously delineated salinity and temperature responses of North Atlantic dominant seagrass species. Herein we examine the critical factor of various color and intensity of light in estuarine conditions and responses of seagrass to their changes. The changing color and intensity of light in estuaries is complex due to changes created by seawater and DSO , and other water substances, riverine input, turbidity by winds and input, and anthropogenic sources of effluents (point source, and sheet flow). Our non-destructive, non-intrusive spectral methods include incubation with various colored light filters of whole living plants measured spectral reflectance, partial absorption and first derivative and analysis of spectral indices from whole living plants of Zostera marina, Thalassia testudinum, Syringodium filiforme, Halodule wrightii , n=72. Incubation times were 6 h and 24, 48, and 72 hours. Intensities examined were 75%, 40%,23& and 10% of full light. These values and pigment activations are compared for Zostera to field specimens with incubation times of several weeks by a second group of workers. The comparison of responses of 4 species to white light vs. blue shows profound pigment changes, in the accessory pigment and spectral region of Chlorophyll a and b . Response changes to intensity levels range from photo-protection responses at high light levels to activation of accessory pigments in a variety of light conditions. Physiological responses to the array of colors and intensities will be delineated. Spectral data and analysis of spectral reflectance indices ARI, BGBO, various carotenoid indices, RedGreen Edge CRIg and CRI red versus presently standard but less sensitive indices NDVI and CNDVI and an array of other indices such as PRI, SIPI,MND705, SR680,DD, Green and Red edges will be discussed. Implications into physiological adaptation of marine plants under green and blue light conditions will be examined. Intertidal vs. subtidal plants responses to color and intensity will be compared. Predictions for usage and recommendations for future usage are included.

Broader Impacts:

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1 - Yale University, School of Forestry and Environmental Studies, 370 Prospect St. , New Haven , Ct., 06511, USA
2 - Yale University, School of Foresty & Evironmental Studies, GREELEY LAB-370 PROSPECT ST, NEW HAVEN, CT, 06511, USA
3 - Wesleyan University , Dept. Earth and Environmental Sciences, Middletown, CT, usa

seagrass remote sensing
spectral reflectance
partial absorption
Thalassia testudinum
Syringodium filiforme
reflectance indices
Blue light
white light
green light
red edge
green edge
caratenoid green edge
caratenoid red edge.

Presentation Type: Oral Paper:Papers for Sections
Session: 17
Location: Newberry/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 8:45 AM
Number: 17002
Abstract ID:517
Candidate for Awards:None

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