# Potential Use of Carrageenanans against the Limestone Proliferation of the Cyanobacterium
## 3 Results
### SEM and Colorimetric Analyses  
SEM analysis confirmed that _P. sesnandensis_ was able to colonize an extensive area in the absence of treatment with carrageenan's (Figure 1i,j), while this was largely avoided by the latter (Figure 1k,l).  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Unpaired \(t\) Test** & **Detail** \\ \hline \(p\) value & 0.0288 \\ \(p\) value summary & * \\ Significantly different (\(p<0.05\))? & Yes \\ t, df & t = 3341, df = 4 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Statistical analysis regarding differences in the stone colonization/proliferation area by _P. sesnandensis_ in the absence and in the presence of carrageenan'n extracts (control vs. treatment).  
Colorimetric analysis was performed in order to evaluate chromatic changes on the stone replicas, either caused by experimental conditions (humid vs. dry), the proliferation of _P. sensandensis_ or the application of carrageenanans. Samples subjected to _P. sensandensis_ inoculation without biocide treatment presented \(\Delta\)E* values of 39.57 (Table 2). On the other hand, when treatment was applied, the \(\Delta\)E* values decreased significantly (16.73) and were revealed to be similar to the experimental controls with and without treatment (10.22 and 15.70, respectively) (see Table 2). These large differences reflect the biofilm development, which is clearly enhanced on the non-treated stone replicas. Results from the non-experimental control replicas revealed that the application of the biocide did not cause any significant color variation on stone (\(\Delta\)E* = 1.10; Table 2). The observed changes in \(\Delta\)E* values for the control replicas with treatment under experimental vs. non-experimental conditions result from the different types of environments (humid vs. dry). Thus, under a humid environment (i.e., experimental conditions), the \(\Delta\)E* value of the control stones with carrageenanans increases (10.22) but follows a similar pattern verified for the control stones without treatment (15.70) (See Table 2). Complementarily, the graphic analysis for color reflectance (Figure 2) also confirms these assumptions.  
\begin{table}
\begin{tabular}{l c c c c} \hline  & **L*** (D65)** & **a*** (D65)** & **b*** (D65)** & \(\Delta\)E* \\ \hline Stone Control (Non-experimental) & 70.82 (\(\pm\)0.13) & 6.36 (\(\pm\)0.99) & 22.37 (\(\pm\)2.26) & 0 \\ Biocide on Stone Control (Non-experimental) & 71.50 (\(\pm\)1.41) & 7.21 (\(\pm\)0.19) & 22.56 (\(\pm\)1.00) & 1.10 \\ Stone Control Experimental & 55.93 (\(\pm\)0.81) & 10.58 (\(\pm\)1.69) & 24.97 (\(\pm\)5.28) & 15.70 \\ Biocide on Stone Control Experimental & 62.69 (\(\pm\)0.56) & 9.15 (\(\pm\)1.20) & 27.90 (\(\pm\)4.49) & 10.22 \\ Inoculated Organism on Stone Experimental & 31.72 (\(\pm\)8.90) & 3.62 (\(\pm\)1.61) & 16.91 (\(\pm\)1.56) & 39.57 \\ Inoculated Organism on Stone with Biocide Experimental & 55.34 (\(\pm\)6.60) & 10.23 (\(\pm\)2.83) & 27.39 (\(\pm\)4.25) & 16.73 \\ \hline \end{tabular}
\end{table}
Table 2: Colorimetric analysis (n = 3) and standard deviation values of the stone replicas subjected to the carrageenan treatment and the growth of _P. sensandensis_.  
Figure 1: Results regarding visual examination (stereomicroscopy and SEM) of the stone probes inoculated with _Parakomarekiella essandensis_ in the absence (**a,b,e,f,i,j**) and in the presence (**c,d,g,h,k,l**) of 200 \(\mu\)L of kappa/iota hybrid carrageenanans, after 4 months of incubation. Scale bars: (**a–d**) = 1 cm; (**i,k**) = 20 \(\mu\)m; (**j**) = 2 \(\mu\)m; (**l**) = 5 \(\mu\)m. Amplification of (**e–h**) = 20\(\times\).