## 3 Results
### Biodiversity Observations
#### 3.3.2 Isolation of Indigenous Ureolytic Bacteria  
The isolation of indigenous ureolytic bacteria analysis was carried out in the Biotechnology Laboratory UGM. The beachrock samples by the seashore and other outcrops found in Krakal-Sadranan were placed in sterile tubes and diluted 10-10\({}^{4}\) times with artificial seawater. Afterwards, 10 \(\upmu\)L of each dilution was added to ZoBell2216E agar medium for marine bacteria and being incubated at 37 \({}^{\circ}\)C for 3 days. The cells cultured were ureolytic bacteria in ZoBell2216E and NH\({}_{4}\)-YE media, which also contained 5.0/L hipolypettone (Nihon Seiyaku Co., Ltd., Tokyo, Japan), 1.0 g/L FePO\({}_{4}\) (Junsei Chemical Co., Ltd., Tokyo, Japan), and 1.0 g/L yeast extract (BD Bioscience Adv., Bioprocessing, Miami, Florida, USA). These were prepared with artificial seawater with pH 7.6-7.8, adjusted using 1 M NaOH [39].  
After 72 h, medium-cultured colonies (aggregates of bacteria) were grown, and then counted to determine which plates were populated with 20-100 medium colonies, which had higher probability of being ureolytic bacteria. Using a sterilized toothpick, each colony from the selected medium was moved into its own medium for the next step, which was to select urease bacteria using a cresol red solution. Urease activity measured in a 10 mL solution was put into a polystyrene screw bottle. Furthermore, transfer a certain amount of bacteria in solid medium using sterilized toothpick, then taken and added to a polystyrene screw bottle containing the urease activity measurement solution. The total potential urease bacteria found is less than 5% as the percentage ratio of ureolytic bacteria among the 527 colonies from the total number isolated from the rock samples. The diversity of microbes known in beachrock encompass three recognized ureolytic bacterial groups, most of which species are assorted microbial eukaryotes. The most frequently isolated 16S rDNA gene sequences include those from acid bacteria, Actinobacteria, and Chloroflexi [40; 41; 42]. The results of a homology search in the GenBank/DDBJ/EMBL, three group of bacteria that were highly homologous to the 16S rDNA nucleotide sequence of the species whereas _Oceanobacillus profundus_ (CIP109535-HQ595230), _Vibrio Maritimus_ (R40493-GU929925), and _Pseudoalteromonas tetradonis_ (KMM458-AF214729). The strains in the 16S DNA gene sequences are shown in Figure 4. The _O. profundus_ is a gram-positive species that are motile, aerobic, rod-shaped (0.2-0.4 \(\upmu\)m) and classified as biosafety level 1 bacteria. The others, _V. maritimus_ and _P. tetradonis_ are gram-negative. The former are motile bacilli 1 \(\upmu\)m wide and 1.5-4.0 \(\upmu\)m, whereas the latter are strictly aerobic, motile with one polar flagellum, form either straight rods (or rod-shapes), 0.5-0.8 \(\times\) 1.0-1.5 \(\upmu\)m when in exponential growth phase. Even though _V. maritimus_ and _P. tetradonis_ are classified as biosafety level 1, but further analysis of _Vibrio maritimus_ caused it to be eliminated because of similarity to _Vibrio cholerae_ (i.e., _V. cholerae_).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multicolumn{6}{c}{**Location 07\({}^{\circ}\)08\({}^{\prime}\)42,55\({}^{\circ}\)–110\({}^{\circ}\)26\({}^{\prime}\)11,31\({}^{\circ}\)**} \\ \cline{2-7}  & **Division** & **Class** & **Ordo** & **Familia** & **Genus** & **Species Name** \\ \hline
1. & & & Ceramiles & Rhodomelaceae & Laurencia & Laurencia pappilosa ([PERSON]) [PERSON] \\ \hline
2. & & & & & & \\ \cline{3-6}  & Rhodophyta & & & & & \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & & \\ \hline
5. & Phaeophyta & Phaeophyceae & Fucales & Sargassaceae & Sargassum & Sargassum \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & & \\ \cline{3-6}  & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Algae species taxonomy surrounded beachrock.