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: Community Structure of Bivalve and Its Relationship with the Seagrass Ecosystem on Tidung Kecil Island, Seribu Islands.
Abstrak: Pulau Tidung Kecil merupakan pulau yang memiliki padang lamun yang dapat menunjang keberlangsungan hidup organisme laut salah satunya bivalvia. Penelitian bertujuan menganalisis struktur komunitas bivalvia dan keterkaitannya dengan ekosistem lamun di Pulau Tidung Kecil, Kepulauan Seribu. Penelitian dilakukan pada empat stasiun dengan tiap stasiun diukur kualitas lingkungan perairan dan sedimen. Pengambilan data lamun dan bivalvia menggunakan transek garis dengan panjang 50 m dan transek kuadrat ukuran 0,5 x 0,5 m². Hasil penelitian ditemukan empat spesies lamun dengan kerapatan tertinggi yaitu Thalassia hemprichii. Bivalvia yang ditemukan terdiri dari tujuh famili dan 15 spesies, dengan kepadatan spesies tertinggi yaitu Tellina timorensis sebesar 6,67 ind/m2. Kualitas lingkungan perairan Pulau Tidung Kecil tergolong baik dengan substrat dominan pasir. Analisis Koresponden menunjukkan terdapat tiga kelompok keterkaitan bivalvia dan lamun. Famili Tellinidae dan Cardiidae dengan lamun Thalassia hemprichii, Famili Lucinidae, Arcidae dan Veneridae dengan lamun Halophila ovalis dan Enhalus acoroides dan famili Mactridae dan Donacidae dengan lamun Cymodocea rotundata., Tidung Kecil Island is an island that has seagrass beds can support the survival of marine organisms, including bivalves. The study aims to analyze the bivalve community structure and its relationship with the seagrass ecosystem on Tidung Kecil Island, Seribu Islands. The study was conducted at four stations with measures quality of the aquatic and sedimentary. The collection of seagrass data used line transect 50 m and quadrat transect 0,5 x 0,5 m2. The results of the study found four seagrass species with the highest density is Thalassia hemprichii. Bivalves were found consisting of seven families and 15 species, with the highest density is Tellina timorensis at 6,67 ind/m2. The quality of Tidung Kecil Island aquatic environment is good with a dominant sandy substrate. Correspondence analysis showed that there are three groups related of bivalve and seagrass on Tidung Kecil Island. The families Tellinidae and Cardiidae with seagrass Thalassia hemprichii, families Lucinidae, Arcidae and Veneridae with seagrasses Halophila ovalis and Enhalus acoroides and famili Mactridae and Donacidae with seagrass Cymodocea rotundata.
Keyword: bivalve, correspondence analisys, seagrass, Tidung Kecil Island

Judul: Penerapan Algoritme Genetika dalam Sistem Permainan Tebak Angka
Abstrak: The number guessing game is a modified game of mastermind created by Mordecai Meirowitz in 1970. The goal of the game is to guess a hidden sequence of numbers stored by others (human or computer) based on values obtained at each guess iteration. In this study, the game is applied into the system by using genetic algorithms, a method that has been successfully utilized to implement the mastermind game on the computer and get an effective solution for the game. Genetic algorithms work through a process of natural selection or commonly known as the evolutionary process, which will continue running until the system finds the optimal 4-digit series of numbers. The system is designed in order to guess those hidden numbers with minimal iterations using c++ programming language. The output of the program shows that the performance is determined by the first guess iteration.
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