## 3 Results  
### Culturable and Total Bacterial Enumeration  
The densities of culturable and total bacteria from seawater and macroalgal biofilms are shown in Table 1 and Figure 3. The densities of culturable free-living bacteria (FLB) at both sites were higher than particle-associated bacteria (PAB) with values of \(1.7\times 10^{3}\) CFU mL\({}^{-1}\) at Stn. 1 and \(2.3\times 10^{3}\) CFU mL\({}^{-1}\) at Stn. 2, respectively (Figure 3a). The density of culturable _Ulva pertusa_ biofilm-associated bacteria on the pumice stone (\(2.4\times 10^{8}\) CFU g\({}^{-1}\) wet weight) was about ten times higher than _U. pertusa_ collected from the floating cage (\(1.9\times 10^{7}\) CFU g\({}^{-1}\) wet weight) (Figure 3b). _Sargassum duplicatum_ associated culturable bacteria showed the lowest density with \(7.9\times 10^{6}\) CFU g\({}^{-1}\) wet weight, and the density of _U. pertusa_-associated culturable bacteria was the highest with \(4.0\times 10^{7}\) CFU g\({}^{-1}\) wet weight at natural macroalgal bed (Stn. 2, Figure 3b). The density of total bacteria in seawater at Stn. 1 was \(2.9\times 10^{6}\) cells mL\({}^{-1}\) (PAB: \(2.6\times 10^{6}\) cells mL\({}^{-1}\), FLB: \(3.1\times 10^{5}\) cells mL\({}^{-1}\)) higher than the density of \(6.7\times 10^{5}\) cells mL\({}^{-1}\) (PAB: \(3.9\times 10^{5}\) cells mL\({}^{-1}\), FLB: \(2.8\times 10^{5}\) cells mL\({}^{-1}\)) at Stn.2 (Figure 3c). In contrast to the culturable bacterial densities, the total PAB densities were higher than those of FLB at both sites (Figure 3a,c). The total bacterial density of _U. pertusa_ on the pumice stone showed the maximum value of \(2.7\times 10^{9}\) cells g\({}^{-1}\) wet weight at Stn. 1 (Figure 3d) as well as culturable bacteria. Total bacterial density of _U. pertusa_ was the highest with the density of \(1.2\times 10^{9}\) cells g\({}^{-1}\) wet weight at Stn.2 as well, followed by _Cladophora diukubaana_ (\(9.9\times 10^{8}\) cells g\({}^{-1}\) wet weight), _Gelidium elegans_ (\(6.0\times 10^{8}\) cells g\({}^{-1}\) wet weight) and _S. duplicatum_ (\(3.9\times 10^{8}\) cells g\({}^{-1}\) wet weight) (Figure 3d). _U. pertusa_ grown on the pumice stone appeared to be unhealthy, turning partly black in decay, and resulted in the highest values of both the densities of culturable and total bacteria at Stn. 1.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Date**} & \multirow{2}{*}{**Station**} & \multirow{2}{*}{**Sample Name**} & \multirow{2}{*}{**Sample Type**} & \multicolumn{2}{c}{**Culturable Bacterial**} & \multicolumn{2}{c}{**Total Bacterial Density**} \\  & & & & **Density (CFU) mL\({}^{-1}\) or** & **(Cells mL\({}^{-1}\) or g\({}^{-1}\) Wet** \\  & & & & **g\({}^{-1}\) Wet Weight)** & **Weight)** \\ \hline \multirow{4}{*}{2017/97} & \multirow{4}{*}{Stn. 1} & \multirow{4}{*}{Sewaurer} & FLB & \(1.7\times 10^{3}\) & \(3.1\times 10^{3}\) \\ \cline{3-6}  & & & PAB & \(1.0\times 10^{3}\) & \(2.6\times 10^{6}\) \\ \cline{3-6}  & & _Ulva pertusa_ on pumice stone & Biofilm & \(2.4\times 10^{6}\) & \(2.7\times 10^{6}\) \\ \cline{3-6}  & & _Ul. pertusa_ on floating cage & Biofilm & \(1.9\times 10^{7}\) & \(1.7\times 10^{7}\) \\ \hline \multirow{4}{*}{2017/98} & \multirow{4}{*}{Stn. 2} & FLB & \(2.3\times 10^{3}\) & \(2.8\times 10^{3}\) \\ \cline{3-6}  & & & PAB & \(1.8\times 10^{3}\) & \(3.9\times 10^{5}\) \\ \cline{3-6}  & & _Sargassum duplicatum_ & Biofilm & \(7.9\times 10^{6}\) & \(3.9\times 10^{8}\) \\ \cline{3-6}  & & _Gidium elegans_ & Biofilm & \(1.5\times 10^{7}\) & \(6.0\times 10^{6}\) \\ \cline{3-6}  & & _Ul. pertusa_ & Biofilm & \(4.0\times 10^{7}\) & \(1.2\times 10^{6}\) \\ \cline{3-6}  & & _Cladophora diukuba_ & Biofilm & \(2.0\times 10^{7}\) & \(9.9\times 10^{8}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of culturable and total bacterial densities enumerated from seawater and macroalgal biofilms at Stns. 1 and 2. (FLB: free-living bacteria, PAB: particle-associated bacteria)