absorption at 430 nm and a higher reflectance value (above 
0.5%) at 535nm. 
Fluorescence and reflectance spectra of PAHs 
T Y 
4 
1 
1 
1 
# 
i 
# 
t 
3 
  
1000 £ 
nou 
TOOr : 
Fluorescence Intensity(a.u.) 
Reflectance(%) 
  
  
300 400 500 600 
Emission(nm) 
Figure 4. Fluorescence and reflectance spectra of PAHs, the 
first y-axis on the left hand side of the plot corresponds to the 
red line, and the second y-axis on the right hand side 
corresponds to the blue line. The red solid line exhibits the 
fluorescence emission of PAHs using excitation at a wavelength 
of 285 nm. The blue solid line shows the reflectance from the 
same sample that is illuminated by a Solux light source. The 
blue dashed curve is a noise signal due to the poor capability of 
the spectrometer to measure reflectance in the UV region. 
In order to examine the reflectance features of different crude 
oil samples, the spectral reflectance measurements were 
performed. Due to the large noise component in the UV 
region, reflectance data are only shown from 400 nm up to the 
near infrared (NIR); see figure 5. 
Spectral reflectance curves of crude oil samples 
T , 7 7 
  
10 
Reflectance(%) 
  
  
  
  
  
Wavelength(nm) 
Figure 5. Spectral reflectance plot of five different crude oil 
samples. 
As shown in figure 5, all the oil samples have a very low 
reflectance at visible (VIS) region of spectrum; value below 
2%. Although reflectance increases at longer wavelengths, 
spectral features are hardly observed at this VIS-NIR region. 
The steep increase in reflectance after 1000 nm suggests that oil 
seepages or spills may be more detectable at these higher 
wavelengths. 
4. DISCUSSION 
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012 
XXII ISPRS Congress, 25 August - 01 September 2012, Melbourne, Australia 
This report described experimental fluorescence and reflectance 
measurements of seawater containing cyanobacteria and crude 
oil samples. From spectro-fluoresence measurements, the 
fluorescence properties of cyanobacteria cellular pigments (PC 
and Chl-a) were obtained along with other two chemical 
substances (Trp and NADPH) that contribute to their total 
fluorescence emission. Also, PAHs within crude oil have 
fluorescence features. Whereas it was not possible to easily 
measure the reflectance of crude oil between 400 and 900 nm 
due to its high absorption, above 1000 nm the reflectance 
increases rapidly. 
Although the capability of cyanobacteria to degrade crude oil 
has been shown by many researchers, none of these are 
observed in situ in marine environments. Also, other non- 
photosynthetic bacteria such as A/canivorax borkumensis are 
reported capable of degrading crude oil in the sea but these 
bacteria species do not live in the upper mixed layer of the 
marine water column but rather down at 1.5 km depth instead. 
However, other phytoplankton species form surface blooms and 
hence biogenic slicks. Therefore, theoretically cyanobacteria are 
able to degrade crude oil in marine environments, and so it is 
worthwhile looking for this behaviour from cyanobacterial 
blooms in situ. Satellite remote sensing is one of the most 
promising techniques that can perform this. However, mapping 
oil spills on the sea surface using optical satellite imagery is 
difficult as there is poor visibility in the VIS-NIR region and the 
signal becomes much stronger in sunglint regions where the 
signature is akin to that seen in Synthetic Aperture Radar (SAR) 
imagery. 
Differentiation of biogenic slicks versus oil slicks could be 
undertaken using fluorescence emission if the signal is 
sufficiently strong to be detectable remotely. However, the 
laboratory results indicate that the thickness of the oil may limit 
the detection. Further investigation is needed in order to take 
these preliminary findings forward. 
5. ACKNOWLEDGEMENTS 
We would like to thank Therese Arredal Harvey of the 
Department of system ecology, Stockholm University and 
Petroleum & Environmental Geochemistry Group, Centre for 
Biogeochemical Research, University of Plymouth for 
providing us with seawater and crude oil samples. We would 
also like to thank UCL Institute of Origins for supporting of 
Lewis Dartnell and the Department of Structural and Molecular 
Biology, UCL for access to the PE LE-55 spectro-fluorimeter 
measurements. 
REFERENCES 
Abed, RM.M. and Koster, J.. The direct role of aerobic 
heterotrophic bacteria associated with cyanobacteria in the 
degradation of oil compounds. Int Biodeterior Biodegrad 
(2005), 55, 29-37. 
Cerniglia C.E., Biodegradation of polycyclic aromatic 
hydrocarbons. Biodegradation (1992) vol. 3 pp. 351-368 
Cerniglia C.E., D.T. Gibson, C.V. Baalen, Oxidation of 
naphthalene by cyanobacteria and microalgae, J. Gen. 
Microbiol. 116 (1980) 495-500. 
    
    
     
     
   
  
  
   
   
    
    
   
     
    
    
  
  
    
  
  
   
      
  
  
  
   
  
  
   
   
   
    
     
    
  
   
    
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