Judul: Fish Community Structure in the Seagrass Ecosystem of Tidung Besar Island, Seribu Islands
Abstrak: Lamun mempunyai peranan penting sebagai tempat pemijahan, pengasuhan, perlindungan, dan mencari makan biota laut, seperti ikan. Akan tetapi, struktur komunitas ikan di ekosistem padang lamun Pulau Tidung Besar masih belum dikaji. Penelitian ini bertujuan menganalisis struktur komunitas ikan di ekosistem padang lamun Pulau Tidung Besar saat kondisi pasang dan surut. Pengumpulan data dilakukan pada bulan Oktober hingga Desember 2023. Pengambilan sampel ikan dilakukan dengan menggunakan jaring insang dengan empat ukuran mata jaring, panjang, dan lebar yang berbeda. Analisis contoh ikan dilakukan di laboratorium. Selama penelitian terkumpul sebanyak 1144 individu ikan yang terdiri dari 12 ordo, 30 famili, dan 70 spesies. Komposisi ikan didominasi oleh Dischistodus chrysopoecilus (betok hitam) sebesar 612 Ind/m2. Kelimpahan dan dominasi spesies lebih tinggi pada saat air pasang, sedangkan kekayaan, keanekaragaman, dan kemerataan spesies lebih tinggi pada saat air surut. Keanekaragaman ikan di Pulau Tidung Besar termasuk ke dalam kategori sedang dengan kondisi yang cenderung stabil., Seagrass has an important role as a habitat for spawning, nurturing, protecting and foraging for marine biota, such as fish. However, the structure of fish communities in the Tidung Besar Island seagrass ecosystem has not yet been studied. This research aims to analyze the structure of fish communities in the seagrass ecosystem of Tidung Besar Island during high and low tide conditions. Fish sampling was carried out using gill nets with four different mesh sizes, lengths and widths. Analysis of fish samples is carried out in the laboratory. During the research, 1144 individual fish were collected consisting of 12 orders, 30 families and 70 species from October to December 2023. The fish composition was dominated by Dischistodus chrysopoecilus (white-spot damsel) at 612 Ind/m2. The abundance and dominance of species is higher at high tide, while species richness, diversity and evenness are higher at low tide. Fish diversity on Tidung Besar Island is included in the medium category with conditions that tend to be stable.
Keyword: community structure, fish, seagrass ecosystem, Tidung Besar Island

Judul: Relationship between Seagrass Community Structure and Habitat Quality in Tidung Island, Seribu Islands
Abstrak: Ekosistem padang lamun merupakan ekosistem penting pesisir. Namun demikian, luas padang lamun di dunia terus menurun setiap tahunnya sekitar 7% per tahun. Salah satu wilayah yang memiliki ekosistem padang lamun adalah Pulau Tidung, Kepulauan Seribu. Penelitian ini bertujuan menganalisis keterkaitan struktur komunitas padang lamun dengan kualitas habitat di Pulau Tidung. Penelitian dilakukan pada bulan November 2023 dengan metode line transect untuk pengamatan lamun. Selain itu, juga dilakukan pengukuran kualitas air dan substrat (fraksi dan C-organik substrat). Analisis data yang digunakan antara lain penutupan jenis lamun, kerapatan jenis, frekuensi jenis, indeks nilai penting, indeks ekologi, serta Spearman rank correlation. Hasil penelitian ini menunjukkan kesehatan padang lamun di Pulau Tidung tergolong kategori miskin hingga kurang kaya/kurang sehat. Jenis lamun yang ditemukan sebanyak enam spesies. Thalassia hemprichii adalah jenis lamun dengan peran terbesar dalam komunitas padang lamun di Pulau Tidung. Kerapatan lamun berkaitan dengan suhu dan liat kasar secara kuat positif. Kandungan C-organik substrat memiliki kaitan yang kuat terhadap penutupan dan kerapatan lamun di Pulau Tidung., Seagrass ecosystems are important coastal ecosystems. However, the area of seagrass beds in the world continues to decline annually by about 7% per year. One of the areas that has seagrass ecosystem is Tidung Island, Seribu Islands. This study aims to analyze the relationship between seagrass community structure and habitat quality in Tidung Island. The research was conducted in November 2023 using line transect method for seagrass observation. Water quality and substrate (substrate fraction and C-organic) were also conducted. Data analysis used included seagrass species closure, species density, species frequency, importance index, ecological index, and Spearman rank correlation. The results of this study show that the health of seagrass beds on Tidung Island is classified as poor to less rich/unhealthy. Six species of seagrass were found with Thalassia hemprichii is a type of seagrass that has the largest role in the seagrass community in Tidung Island. Seagrass density was strongly positively related to temperature and coarse clay. Substrate C-organic content has a strong relationship with seagrass cover and density in Tidung Island.
Keyword: habitat, lamun, Pulau Tidung, struktur komunitas

Judul: Sintesis Flavonol melalui 2’-Hidroksikalkon
Abstrak: Flavonol is a class of flavonoids commonly found in fruits and vegetables. Flavonol is very useful, especially in food sector and health. In this study, flavonol unsubstituted was successfully synthesized from an intermediate material 2’-hydroxychalcone. The 2’-hydroxychalcone was synthesized by Claisen-Schmidt condensation method between o-hydroxyacetophenone and benzaldehyde using 4 different catalysts, namely KOH 60%, solid pellet of KOH-grinding technique, BF3-Et2O, and NaH in DMF. The KOH 60% was the best catalyst, giving the highest yield (57%). Afterward, the flavonol was synthesized in 1-stage oxidation cyclization of o-hydroxyacetophenone using Algar-Flynn-Oyamada (AFO) reaction, giving 76%. The flavonol total yield from 2’-hydroxychalcone was 43%. All synthesized products were characterized by their melting points and their spectra. The success of the synthesis flavonol opens the way to synthesis of useful flavonol derivatives such as quercetin and kaempferol
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