## 3 Results and Discussion  
The samples of the cultured algae revealed that the number of cells was different for each alga. The samples of green algae, namely SDC1, SDC2, SDS1, and SDS2, and those of blue-green algae, namely ABS1, ABS2, ABF1, ABF2, and ABF3, were practically free of algae cells, as these samples were diluted in BG11 (Table 2.). Samples with an algae cell count of 1000 cell/mL or less were excluded from the present study, and analysis was conducted using the spectra of only green and blue-green algae. Figure 7: Algae spectral spectrum ((**a**) algae spectrum—radiometrically calibrated algae spectra, (**b**) BG11 spectrum—radiometrically calibrated BG11 spectra, (**c**) algae spectrum—BG11 spectrum—resultant spectrum of algae with specific spectral features extracted by subtracting the radiometrically calibrated BG11 spectra from the radiometrically calibrated algae spectra). [PERSON] (1996) suggested that chlorophyll reaches a maximum at a wavelength of 441 nm [17]. Our study results showed a similar trend for both green and blue-green algae. All concentrations of green algae had maximum absorption in the wavelength range between 417 and 437 nm, and the second maximum absorption was obtained between 661-673 nm (Table 3.). Blue-green algae had maximum absorption between 433-437 nm at all concentrations, and the second maximum absorption was found between 669-677 nm. [PERSON] (1999) [18], [PERSON] (2000) [19], and [PERSON] (2004) [20] proposed that the absorption in the wavelength range of 450-500 nm may be due to Chl-a, carotenoids, and dissolved organic matter [21]. In this study, the algae spectrum was extracted by subtracting the sample spectrum for algae cultivation from the algae culture media spectrum. As a result, green algae showed an increasing trend between 449-529 nm due to the influence of Chl-a, rather than carotenoids and dissolved organic matter. Moreover, for blue-green algae samples, an additional third absorption peak was obtained between 601 and 633 nm (Table 4 and Figure 8). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Wavelength Range** & **ABS 3** & **ABS 4** & **ABS 5** & **ABS S** & **ABF 4** & **ABF 5** & **ABF S** \\ \hline
1 st Wavelength & 437.48 & 437.48 & 437.48 & 433.48 & 437.48 & 437.48 & 437.48 \\ (nm) & (Band 10) & (Band 10) & (Band 10) & (Band 10) & (Band 10) & (Band 10) & (Band 10) \\ \hline
2 nd Wavelength & 669.74 & 677.75 & 673.75 & 673.75 & 677.75 & 673.75 & 677.75 \\ (nm) & (Band 68) & (Band 70) & (Band 69) & (Band 69) & (Band 70) & (Band 69) & (Band 70) \\ \hline
3 rd Wavelength & 613.68 & 633.70 & 629.70 & 621.69 & 601.67 & 617.68 & 625.69 \\ (nm) & (Band 54) & (Band 59) & (Band 58) & (Band 56) & (Band 51) & (Band 55) & (Band 57) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Absorption wavelength range of selected blue-green algae. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Types of Algal Sample** & _Scenadesmus_ & _Scenadesmus_ **sp.** & _Anabaena flos-aquae_ & _Anabaena_ **sp.** \\  & _communis_ & **(Cells/mL)** & **(Cells/mL)** & **(Cells/mL)** \\ \hline Stock solution \(\times\) 10\({}^{4}\) & 0 & 0 & 0 & 0 \\ Stock solution \(\times\) 10\({}^{3}\) & 633 & 400 & 367 & 0 \\ Stock solution \(\times\) 10\({}^{2}\) & 3600 & 1433 & 1667 & 12,267 \\ Stock solution \(\times\) 10\({}^{1}\) & 11,933 & 60,367 & 28,133 & 282,433 \\ Stock solution & 130,300 & 1,306,100 & 237,000 & 952,067 \\ Seed & 87,983 & 207,737 & 201,080 & 371,613 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of cell count for algal samples used in the study (SDC; _Scenadesmus communis_ stock solution; SDS; _Scenadesmus_ sp. stock solution; ABS; _Anabaena_ sp. stock solution; numbered in descending order of concentration).