Water Field Site 
  
  
  
  
  
  
  
Sr. Coral Colony column (Tidal 
No. Genera Morphology (in cm) Zone) 
Paga 
1 | Favia Massive | 1.50 qne 
Subtidal) 
2 Symphillia Massive 8.00 d tidal) 
Sub- Laku 
3 Goniopora massive 1.50 Point 
M (Intertidal) 
; Sub- Paga 
a Porites massive 2.30 (Intertidal) 
5 | Goniastrea | Encrusting 1.50 A 
6 Platygyra Massive 1.50 EA ih 
Laku 
7 Turbinaria Foliose 4.00 Point 
(Intertidal) 
Turbinaria Dan 
8 (bieached) Foliose 4.00 Point 
(Intertidal) 
  
Table 1. Details of the eight sampled coral targets 
Later analyses were focused on these eight coral targets. In 
general, it was found that there were negligible spectral signal 
received from the coral targets beyond 1350nm. Accordingly, 
simple average spectra and their first and second-order derivatives 
(over 4nm as finite band resolution) were numerically constructed 
for spectral characterization (Hochberg et al. 2003). The spectral 
plots were visually compared. 
  
  
  
  
  
Figure 4. Field photographs of the eight coral targets 
(numbered serially) 
4. RESULTS & DISCUSSION 
Favia was the most dominant scleractinian genus, ubiquitously 
occurring on the inter-tidal reef flat and also in the sub-tidal areas 
of Laku Point and Paga reefs. The second dominant genus was 
Porites followed closely by Goniastrea and Goniopora in both 
the locations. Symphillia was found only in the sub-tidal zones of 
Paga while Turbinaria were sampled from Laku Point. Platygyra 
was sampled from Paga reef. 
     
   
      
   
    
  
  
   
   
      
   
    
    
   
  
    
    
  
  
   
     
   
     
   
  
  
   
   
  
  
   
    
   
  
  
  
  
  
  
  
  
  
  
   
  
  
   
   
  
    
   
    
   
    
   
Figure 5 shows the in situ reflectance spectra of these coral target; 
over the spectral range of 350 to 1350 nm. All corals have centra] 
maxima near 820 nm and another prominent peak at 1070 nm. 
The spectra are marked with two characteristic absorption features 
located at 675nm (chlorophyll absorption) and at 975 nm (water 
absorption). The chlorophyll absorption at 675 nm is followed by 
an abrupt, steep rise in the NIR region. As per the spectral 
characteristics apparent in Figure 5 the eight coral targets can be 
grouped into three distinct groups: Group A consisting of Favia, 
Porites, Goniastrea and Platygyra; Group B comprising of 
Symphillia, Goniopora and Turbinaria (Live) and Group C: the 
bleached Turbinaria. 
Group A corals represent massive, sub-massive and encrusting 
colonies with equal proportion of exposure of soft, live coral 
polyps and their calcium carbonate corallites. Two of the Group B 
corals (Symphyllia and Goniopora) representing massive and sub- 
massive colonies had relatively more exposure of the soft, live 
coral polyps than the calcium carbonate corallites. Turbinaria 
(live) on the other hand represents a foliose colony with more ofa 
calcium carbonate structure with live coral polyps. Group C: the 
bleached Turbinaria represents the same with polyps largely 
devoid of endo-symbiont zooxanthellae. 
  
1 
09 | : Plot: Key 
i Favia 
Symphyllia 
Goniopora 
Porites 
Goniastrea 
Platygyra 
Turbinaria 
Turbinaria (bleached) 
0.8 4 
  
0.7. 
1 
2 
3 
i 
5 
6 
7 
pU 
0.6 + 
0.5 + 
Reflectance 
  
  
  
04 4 Ï a 
if e Pus. 
i 
03 + i # 
m 
024: 4 
044 = J 
ECR V d 
o T T T s 
350 450 550 650 750 850 950 1050 1150 1250 1350 
  
  
Wavelength (nm) 
Figure 5. In situ reflectance spectra of the sampled coral targets 
Group A corals represent the purest form of in situ live coral 
spectra with an average water column of 1.7 cm. The individual 
spectra of these four corals run absolutely parallel to each other 
and have a near-perfect match in terms of their spectral 
architecture (shape). Favia shows the least reflectance over the 
entire range of 350 to 1350 nm, followed by Goniastrea, Porites 
and Platygyra: the last showing the highest reflectance. In visible 
region, Group A spectra conform to the “brown mode” of coral 
spectra (Hochberg et al. 2004) characterized by “triple-peaked 
reflectance pattern’ first reported by Myers et al. in 1999. This 
brown mode of coral spectra generally exhibit a depressed 
reflectance between 400 and 550 nm and triple peaks or local 
maxima/shoulders at 575, 600 and 650 nm. Group A corals 
showed the characteristic chlorophyll absorption feature at 675 
nm due to the presence of photosynthesizing endo-symbiont algaë 
(zooxanthellae) within the host coral tissues (Holden and LeDrew, 
1999). In the NIR region (700 to 1000 nm) these corals show à 
unique, near-symmetrical, bell-shape curve with central maxima 
located at 820 nm. Following the abrupt, steep rise between 69 
and 710 nm, all the spectra gradually increases to 820 nm with ? 
  
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