Judul: Temporal Pattern of Coral Reef Fish Comunity in Tidung Kecil Island Using eDNA Metabarcoding and Underwater Visual Census
Abstrak: Coral reef fish is one of the indicator for assessing the level of biodiversity of a coral reef ecosystem. The existence of coral reef fish can be affected by anthropogenic and natural factors, one of which is a seasonal variability. Various studies have reported that the structure of fish communities can be influenced by seasonal variations. Seasonal monitoring is important to detect temporal variation in fish communities. This study aims to assess the structure of coral reef fish communities based on seasons in Tidung Kecil Island using environmental DNA metabarcoding and Underwater visual census. Underwater visual census was conducted on 250 m2 and 1 L water sample was collected from sediment. The sample extraction was carried out using a Zymo Research Extraction Kit and follwed by PCR process using MiFish primers targeting 12S rRNA, then sequencing using Next Generation Sequencing from Illumina Nextseq 500. Sequencing product was analyzed using MiFish Pipeline and followed by abundance and ecological index analysis. The UVC identified 32 species belonging to 10 families in the rainy season and 29 species belonging to 7 families in the dry seasons. The eDNA metabarcoding identified 209 species belonging to 56 families and 27 species belonging to 17 families in the western and eastern seasons, respectively. Based on eDNA metabarcoding data, coral reef fish abundance and community composition differed significantly between seasons (Mann Whitney, p<0.01), while the UVC method did not detect these seasonal differences (Mann Whitney, p>0.05). Based on group category, fish abundance was dominated by major and target fish in west and eastern seasons both using UVC and eDNA. Diveristy indice did not differ significantly between seasons for either method. The Similarity Percentages (SIMPER) analysis was discovered Pomacentrus alexanderae (10.24%) and Abudefduf vaigiensis (44.40%) as highest contribution in western and eastern season using UVC, while Planiliza macrolepis (66.54%) and Plectropomus aerolatus (8.80%) in western and eastern season using eDNA., Ikan terumbu karang merupakan salah satu indikator dalam menilai keanekaragaman hayati di ekosistem tersebut. Keberadaan ikan terumbu karang dapat dipengaruhi oleh faktor antropogenik maupun faktor alam, salah satunya adalah faktor perubahan musim. Beberapa penelitian telah melaporkan bahwa struktur komunitas ikan dapat dipengaruhi oleh variasi musim. Kegiatan monitoring secara musiman sangat penting untuk mendeteksi variasi temporal pada komunitas ikan. Penelitian ini bertujuan untuk mengkaji struktur komunitas ikan terumbu karang berdasarkan musim di Pulau Tidung Kecil dengan menggunakan metabarkoding DNA Lingkungan dan Sensus Visual. Pengamatan secara sensus visual dilakukan dengan luas area 250 m2 , dan sampel air laut diperoleh dari bagian sedimen sebanyak 1 L. Proses ekstraksi sampel dilakukan dengan menggunakan protokol dari Kit Zymo Research, USA dan dilanjutkan dengan proses PCR menggunakan primer MiFish U dengan target lokus 12S rRNA. Sekuensing sampel dilakukan dengan menggunakan Next Generation Sequencing dari Illumina Nextseq 500. Produk sekuensing dianalisis menggunakan perangkat lunak MiFish Pipeline dan dilakukan analisis lebih lanjut mengenai kelimpahan dan indeks ekologi. Penelitian ini berhasil mengidentifikasi 32 spesies pada musim barat dari 10 famili dan 29 spesies dari 7 famili pada musim timur menggunakan UVC, sedangkan eDNA berhasil mendeteksi 209 spesies dari 56 famili pada musim barat dan 27 spesies dari 17
Keyword: Next generation monitoring, Underwater Visual Census, Seasonal Abundance, Reef Fish

Judul: Detection of Reef Fish Communities Using  Environmental DNA in the Core Zone Area of Seribu Islands National Park
Abstrak: Ikan merupakan taksa terbesar dari hewan vertebrata yang bersimbiosis dengan terumbu karang. Ikan terumbu memegang peranan penting sebagai grazer yang mengontrol pertumbuhan alga, mempunyai nilai ekonomis penting dalam bidang perikanan, dan sebagai daya tarik bagi para wisatawan. Penelitian ini bertujuan mengetahui struktur komunitas ikan terumbu di kawasan Zona Inti Taman Nasional Kepulauan Seribu menggunakan DNA lingkungan (eDNA). Metode eDNA telah berkembang dan banyak digunakan dalam pemantauan keanekaragaman hayati laut. Penelitian ini berhasil mendeteksi ~40.081 paired-end sekuens dari empat lokasi penelitian. Sebanyak 46 spesies dari 33 genus teridentifikasi sebagai ikan terumbu. Penelitian ini berhasil mendeteksi kelompok ikan mayor dan target, namun ikan indikator tidak terdeteksi. Ikan carnivore mendominasi di seluruh lokasi penelitian sedangkan ikan herbivore paling sedikit ditemukan di penelitian ini. Lokasi penelitian memiliki nilai indeks keanekaragaman yang sedang, keseragaman yang tinggi, dan dominansi yang rendah., Fish are the largest group of vertebrate animals that live alongside coral reefs. They are essential in coral reef ecosystems, as they graze on algae, have economic value in fisheries, as well as being attractions for tourists. This study aims to determine the community structure of reef fish in the Core Zone Area of Seribu Islands National Park using the Environmental DNA (eDNA) method. The eDNA method has evolved and is widely employed in monitoring marine biodiversity. This study detected ~40,081 paired-end read sequences from four study sites. A total of 46 species from 33 genera were identified as reef fish. The highest species and family richness were found in East Peteloran, with 23 species from 14 reef fish families. This study successfully identified major and target fish groups but did not find any indicator groups. Carnivorous fish dominated all study sites, while herbivorous fish were least found in this study. The study sites showed moderate diversity, high evenness, and low dominance.
Keyword: Community structure, Environmental DNA, Diversity, Reef Fish

Judul: Natrium lignosulfonat sebagai agen pendispersi pada mortar
Abstrak: Lignosulphonate, a modification product of lignin waste from pulp and paper industry can be used as water reducer in mortar mixture. This substance can influence the mechanical characteristic of mortar such as diameter of flow, flexural strength, compressive strength, and setting time of cement paste. Lignosulphonate shows it function as dispersant on cement hydration at 3 days that analyzed with x-ray difractometer. Research result show that flow of fresh mortar rise with increase concentration (from weight of cement) of synthetic sodium lignosulphonate (NaLS). It show that mortar homogenity also increasing. The result of flexural strength and compressive strength test use synthetic NaLS 0.1-0.3% from weight of cement show that addition synthetic NaLS 0.2% is the best result because it has the biggest of flexural strenght and compressive strength value. Initial setting time of cement paste increase, about 50% with addition of synthetic NaLS 0.2%. Whereas the final setting time decrease, about 8%. Cement hydration test show increase hydration product peak, Ca(OH)2 dan calcium silicate hydrate (C-S-H).
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