MARINE MACROALGAE BIODIVERSITY OF UJUNG GENTENG COASTAL AREA, WEST JAVA, INDONESIA BASED ON MORPHOLOGICAL AND GENETIC MARKER 18S RRNA

• Main Author: Yessy
• Format: Dissertations
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/75045
• Institution: Institut Teknologi Bandung

Macroalgae are photosynthetic organisms which are macrobenthic (large and attached) forms of marine algae. Macrolgae are widely used in the sectors of food, agriculture, cosmetics, and pharmaceuticals. Approximately 8.6% of the total marine biota in Indonesia are macroalgae, which occupy an area of about 1.2 million hectares of ocean or the largest in the world. Ujung Genteng coastal area has high biodiversity because it is a relatively unspoiled coastal area with a wide intertidal zone and consists of a variety of habitats. Several studies on macroalgal diversity have been conducted in the Ujung Genteng coastal area. All of these diversity studies still use classical methods: morphological analysis. Morphological identification of species is often inaccurate due to morphological similarities, leading to loss of information regarding species composition in an ecosystem or in an area. The molecular method approach using genetic markers is very useful in studying species, especially macroalgae and can answer questions about the relationship between taxa (taxa) and populations and divergence. Molecular methods can overcome deficiencies in morphological studies used previously. DNA sequence information enables the identification of species that were previously ambiguous and hidden in an environment. The 18S rRNA gene sequence can be used as a genetic marker for the identification of macroalgae species because it has conserved and variable regions that are useful in species determination. This study aims to examine the diversity of macroalgae in Ujung Genteng coastal area, West Java, Indonesia based on morphology and genetics with the 18S rRNA marker gene. The assessment was carried out at two locations on Ujung Genteng Beach, namely Location 1 which is categorized as an unpolluted beach because due to the lack of human, domestic, transportation and industrial activity, and Location 2 which is categorized as a polluted coastal area because there are human, domestic, transport or industrial activities take place around it. The research methodology included: (i) macroalgae sampling in the Ujung Genteng coastal area, West Java; (ii) measurement of seawater conditions for macroalgae habitat including measurements of pH, temperature, salinity, and metal content; (iii) morphological analysis of macroalgae samples; (iv) total DNA isolation from macroalgae samples; (v) amplification of the 18S rRNA gene using the PCR method (vi) determination of its nucleotide sequence using the Sanger sequencing method; (vii) identification of macroalgae species based on the nucleotide sequence of the 18S rRNA; (viii) phylogenetic analysis of macroalgae samples based on the 18S rRNA sequences. The samples obtained from Location 1 consisted of 24 types of macroalgae, which were coded M1.1 to M1.24. While samples from Location 2 obtained 21 types of macroalgae coded M2.1 to M2.21. The total macroalgae samples obtained consisted of 17 genera, 15 families and 4 classes. In the process of identifying macroalgae samples based on morphology and 18S rRNA gene sequence, four categories of conditions were obtained, namely (i) macroalgae samples that were confirmed morphologically at the genus level could be identified to the species level by 18S rRNA sequence; (ii) samples of macroalgae identified to the species level, both morphologically and genetically with the 18S rRNA gene sequence; (iii) macroalgae samples identified morphologically in a different genus/species from the identified genus/species by the 18S rRNA gene; (iv) morphologically confirmed macroalgae samples due to the absence of 18S rRNA gene sequence data (18S rRNA gene amplification was unsuccessful in some samples. The phylogenetic tree consisted of clades showing the grouping of red macroalgae, brown macroalgae, and green macroalgae. The diversity of macroalgae at both Locations 1 and 2 was quite different from the finding of several types of species that only grew in Location 1, and several other types only of growth in Location 2. The type of macroalgae that had the highest overall distribution/abundance which included Locations 1 and 2 was Enteromorpha sp., followed by Gracilaria corticata. While the most abundant type of macroalgae in Location 1 was Enteromorpha sp, followed by Chaetomorpha brachygona, while Location 2 was Cladophora vagabunda, followed by Padina australis. Location 2 which contains lead (Pb) 8.2 times higher than location 1 is dominated by brown macroalgae Padina sp. so it is suspected that Padina sp. (effective metal bioindicator) is more resistant to higher levels of Pb Metal. Several new types of macroalgae were revealed in this study to exist in Ujung Genteng Beach, namely Palisada sp. (GenBank access codes OQ938823), Gracilaria curtissiae, Gracilaria canaliculata (OQ938824, OQ938832, OQ938836, OQ938842, OQ938847) and Wurdemannia miniata (OQ930737). The use of 18S rRNA genetic markers provides more precise identification than morphological analysis only. The macroalgae grown at Location 1 were macroalgae that cannot grow in high-lead seawater (Enteromorpha sp. and Chaetomorpha brachygona), and the macroalgae grown at Location 2 were macroalgae that could grow at high seawater lead levels (Cladophora vagabunda and Padina australis).