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: Community Structure of Reef Fish in Coral Reef Ecosystem on Tidung Island, DKI Jakarta
Abstrak: Ekosistem terumbu karang merupakan ekosistem produktif untuk perikanan dan organisme akuatik lainnya. Ekosistem terumbu karang menjadi habitat vital bagi komunitas ikan khususnya ikan terumbu. Ikan terumbu adalah komponen penting di lingkungan perairan, keberadaan komunitas ikan terumbu pada ekosistem terumbu karang penting untuk diketahui, karena peran dan fungsi secara ekologi ikan dalam menjaga kestabilan komunitas terumbu karang dan keseimbangan komponen penyusun ekosistem terumbu karang lainnya. Penelitian ini bertujuan mengetahui struktur komunitas ikan terumbu di Pulau Tidung. Penelitian ini dilakukan di Pulau Tidung pada tanggal 9 - 12 Juni 2022. Metode pengambilan data ikan terumbu menggunakan Underwater Visual Census (UVC) dengan transek 50 meter, dan diletakkan tiga transek di setiap stasiunnya. Data ikan terumbu dianalisis dengan tiga indeks komunitas, yaitu indeks keanekaragaman, indeks keseragaman, dan indeks dominansi. Hasil penelitian ditemukan 3982 individu ikan terumbu, 24 famili dan 91 spesies. Komposisi ikan indikator sebesar 2,44%, target 17,20%, dan ikan mayor sebesar 80,36% dari total individu yang ditemukan. Nilai rata-rata indeks keanekaragaman 2,77, keseragaman sebesar 0,88, dan dominansi 0,08. Nilai ini menunjukkan bahwa kondisi komunitas ikan terumbu di Pulau Tidung tergolong baik, stabil, dan tidak ada dominansi antar spesies., Coral reef ecosystems are productive ecosystems for fisheries and other aquatic organisms. Coral reef ecosystems are vital habitats for fish communities, especially reef fish. Reef fish are important components in the aquatic environment, the existence of coral fish communities in coral reef ecosystems is important to know, because of the ecological role and function of fish in maintaining the stability of coral reef communities and the balance of other components of coral reef ecosystems. This study aims to determine the structure of the reef fish community on Tidung Island. This research was conducted on Tidung Island from 9 June to 12 June 2022. The reef fish data collection method uses Underwater Visual Census (UVC) with a 50 meter transect, and placed three transects at each station. Reef fish data were analyzed with three community indices, namely diversity index, uniformity index, and dominance index. The results of the study found 3982 individuals of reef fish, 24 families and 91 species. The composition of indicator fish is 2,44%, target is 17,20%, and major fish is 80,36% of the total individuals found. The average value of diversity index is 2,77, uniformity is 0,88, and dominance is 0,08. This value indicates that the condition of the reef fish community on Tidung Island is good, stable, and there is no dominance between species.
Keyword: Community structure, reef fish, Tidung Island, Underwater Visual Census

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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