Padang lamun memiliki peranan yang penting dalam menjaga keseimbangan ekosistem laut, baik dari aspek ekologis, biologis, maupun fisik. Kondisi padang lamun dapat dilihat berdasarkan tipologi habitat, seperti di Pulau Panjang, Pulau Derawan dan Reef Flat Masimbung. Pulau Panjang memiliki ekosistem mangrove, padang lamun, Reef Flat dan minim aktivitas manusia dibandingkan dengan Pulau Derawan yang padat aktivitas manusia, namun memiliki padang lamun dan Reef Flat. Untuk lokasi Masimbung hanya berupa hamparan Reef Flat dan padang lamun
saja. Penelitian bertujuan untuk menganalisis karakteristik padang lamun berdasarkan tipologi habitat di Pulau Panjang, Pulau Derawan, dan Reef Flat Masimbung. Penelitian dilaksanakan pada Desember 2023 hingga April 2024 menggunakan metode kuantitatif dan pemodelan. Parameter yang diukur meliputi parameter ekologi (kerapatan, tutupan dan kekayaan jenis lamun) serta parameter kualitas air (suhu, salinitas, pH, kecerahan, DO, TSS, minyak dan lemak, amonia, orto-fosfat dan nitrat). Sebanyak 50 sampel lamun dan air diambil menggunakan transek kuadrat berukuran 0,5 m x 0,5 m, yang dianalisis dengan metode Multi Dimensional Scaling (MDS). Hasil penelitian tutupan lamun pada ketiga lokasi yaitu berkisar 37%-64%. Kerapatan lamun pada ketiga lokasi yaitu berkisar 10-147 individu/m². Pada kekayaan jenis lamun yang ditemukan di ketiga lokasi memiliki sebanyak 5 jenis lamun yaitu Thalassia hemprichii, Halophila ovalis, Cymodocea rotundata, Syringiodium isoetifolium, Holudule uninervis. Parameter kualitas air menunjukkan suhu berkisar antara 28–30°C, salinitas 36-37‰, pH 6,65-8,73, kecerahan 100%, DO 6,2-6,5mg/L, TSS 0,153-0,449mg/L, minyak dan lemak 0,028-0,249mg/L, ammonia total 0-0,106 mg/L, orto-fosfat 0-0,047mg/L dan nitrat 0-0,016mg/L. Analisis MDS menunjukkan bahwa secara umum tidak ada perbedaan meskipun ada variasi antar lokasi tapi hasil skoring pemodelan menunjukkan satu bentang ekosistem yang identik (sama) namun ada variasi unsur yang berbeda.

Kata Kunci: Ekosistem Pesisir, Kualitas Air, Padang Lamun

Seagrass beds play a crucial role in maintaining the balance of marine ecosystems, encompassing ecological, biological, and physical aspects. The condition of seagrass beds can be assessed based on habitat typology, as exemplified by Panjang Island, Derawan Island, and the Masimbung reef flat. Panjang Island features ecosystems including mangroves, seagrass beds, and reef flats, with minimal human activity compared to Derawan Island, which experiences high human activity but also possesses seagrass beds and reef flats. The Masimbung location primarily consists of reef flats and seagrass beds. This research aims to analyze the characteristics of seagrass beds based on habitat typology across Panjang Island, Derawan Island, and the Masimbung Reef Flat. The study was conducted from December 2023 to April 2024, employing a quantitative descriptive method. Measured parameters included ecological parameters (seagrass density, coverage, and species richness) and water quality parameters (temperature, salinity, pH, clarity, dissolved oxygen (DO), total suspended solids (TSS), oil and grease, ammonia, orthophosphate, and nitrate). A total of 50 seagrass and water samples were collected using 0.5 m x 0.5 m transect quadrats, which were analyzed using the Multi-Dimensional Scaling (MDS) method. The results indicated seagrass coverage ranging from 37% to 64% across the three locations. Seagrass density varied from 10 to 147 individuals/m². The species richness of seagrass found across the three locations comprised 5 species: Thalassia hemprichii, Halophila ovalis, Cymodocea rotundata, Syringodium isoetifolium, and Holodule uninervis. Water quality parameters revealed temperatures between 28-30°C, salinity of 36-37%, pH of 6.65-8.73, clarity of 100%, DO of 6.2-6.5 mg/L, TSS of 0.153-0.449 mg/L, oil and grease of 0.028-0.249 mg/L, total ammonia of 0-0.106 mg/L, orthophosphate of 0-0.047 mg/L, and nitrate of 0-0.016 mg/L. The MDS analysis demonstrated that, in general, there were no significant differences, although variations existed between locations. However, the modeling scoring results indicated a single, identical ecosystem landscape, with variations in specific elements. Keywords: Coastal Ecosystems, Water Quality, Seagrass Beds