Environmental factors and geographical variations in an ecosystem are important steps in explaining the dynamics of marine communities, a study of seaweed that grows naturally on the west coast of Simeulue Island was conducted with the purpose of learning about the environmental characteristics, geographical variations, and environmental parameters that affect their distribution. The study was conducted in October 2021, and it included 5 observation stations with environmental factors measured in situ and geographic variation data using line transects along 50 m perpendicular to the shoreline and sample plots measuring 1 x 1 m every 10 m. Environmental factors that influence vegetation conditions and geographic variations of seaweed were analyzed using PCA. The study's findings revealed that conditions in the Indian Ocean with a high pH (average 07.72 ± 00.20) with moderate salinity and current velocity (average 32.47‰± 01.72 and 00.32 m/s ± 00.11, respectively) influenced the seaweed vegetation habitat. Then 21 seaweed species were identified, all of which have not been evaluated on the IUCN Red List, and their distribution is relatively rare, with a frequency of only 20%, and the seaweed zoning found at a depth of 0 - 150 cm at the lowest tide and a distance of up to 40 m inland from the edge. Furthermore, the distribution of seaweed on Simeulue Island's west coast is largely determined by DO conditions, salinity, and current velocity, whereas pH and temperature have less influence on seaweed distribution.  Faktor lingkungan dan variasi geografik di suatu ekosistem merupakan langkah penting dalam menjelaskan dinamika komunitas laut, sehingga kajian rumput laut yang tumbuh alami di Pantai Barat Pulau Simeulue dilakukan dengan tujuan untuk mengetahui karakteristik lingkungan, variasi geografik dan parameter lingkungan yang mempengaruhi distribusinya. Kajian dilaksanakan pada bulan Oktober 2021 yang terdiri dari 5 stasiun pengamatan dengan faktor lingkungannya diukur secara in situ dan data variasi geografiknya menggunakan transek garis sepanjang 50 m tegak lurus garis pantai serta dibuat petak contoh berukuran 1 x 1 m disetiap 10 m dan faktor lingkungan yang mempengaruhi kondisi vegetasi maupun variasi geografik rumput lautnya dianalisis menggunakan PCA. Hasil kajian memperlihatkan bahwa habitat vegetasi rumput lautnya dipengaruhi oleh kondisi Samudera Hindia dengan konsentrasi pH perairannya tergolong tinggi (rata-rata 07.72 ± 00.20) dan konsentrasi salinitas maupun kecepatan arusnya tergolong sedang (rata-rata 32.47‰ ± 01.72 dan rata-rata 00.32 m/s ± 00.11), kemudian rumput lautnya teridentifikasi sebanyak 21 spesies yang keseluruhannya belum terevaluasi di IUCN Red List dan distribusinya tergolong jarang dengan frekuensi relatifnya kecil dari 20% serta zonasi rumput lautnya ditemukan pada kedalaman ± 0 – 150 cm saat surut terendah dan berjarak hingga ± 40 m ke arah daratan dari tubir. Selanjutnya, untuk distribusi rumput laut di pantai Barat Pulau Simeulue sangat ditentukan oleh kondisi DO, salinitas dan kecepatan arus, sedangkan parameter pH dan suhu kurang memberikan pengaruh yang baik terhadap distribusi rumput lautnya.

Shellfish (bivalves) are potential biodiversity of waters with an important significant value used by the community as a food source of highly nutritious animal protein. Based on survey results, several coastal areas in North Aceh District have the potential for shellfish. Still, there have not been any scientific reports on this region's proximate composition of bivalves. This study aims to determine the relative arrangement of the dominant bivalves in the North Aceh District based on species differences and environmental characteristics. The results showed varying proximate bivalve proximate compositions of 4 chief types of shellfish in North Aceh waters. Bivalvia water ranged from 6.9-14.2%, ash ranged from 5.87-8.29%, protein ranged from 32.84-35.87%, fat ranged from 3.04-10.83%, and carbohydrate ranged from 38.11-42.71%. The highest protein and fat content were found in the Crassostrea sp1 type clams. In addition, the differences in the environmental characteristics of the shell sampling locations also resulted in different proximate compositions. The PCA test results showed that the critical variablarrangemente composition was ash and fat content. The environmental parameters, which were the key parameters of the relative arrangement of the shells were the substrate and pH.

The growth of an organism can provide fundamental ecological data and serve as a primary parameter for describing an organism's population dynamics. Telescopium telescopium gastropods were studied in September 2021 using purposive sampling in the mangrove forest of Cut Mamplam Village, Aceh Province. This study aims to provide fundamental data for mangrove management in Indonesia. Data were collected by creating a 40 m perpendicular to the coastline line transect, followed by 10 x 10 m sample plots and five 1 x 1 m sub plots. Following the collection of samples, additional analysis of the density, length and weight relationship, demographic structure, spatial distribution patterns based on the Morisita index, and growth characteristics were conducted as unique characteristics when compared to T. telescopium in other areas analyzed using PCA. The study's findings indicated that the density was low (< 7 ind/m2), the allometric length and weight relationship was negative (b < 3), the dominant growth demographic structure was mature (dominant SL 79.36 – 86.34 mm), the distribution pattern was clustered (Iδ = 02.75), and the BT, BWL, and AL morphometrics, in particular, had a variance of 95.91%. Pertumbuhan suatu organisme dapat menyediakan data ekologi dasar dan merupakan salah satu parameter yang utama dalam mengambarkan dinamika populasi suatu organisme, sehingga kajian gastropoda Telescopium telescopium di hutan mangrove Desa Cut Mamplam Provinsi Aceh dilakukan menggunakan purposive sampling pada bulan September 2021 dengan tujuan sebagai data dasar dalam pengelolaan mangrove di Indonesia, dimana data dikumpulkan dengan cara membuat transek garis sepanjang 40 m tegak lurus garis pantai, kemudian dibuat petak-petak contoh berukuran 10 x 10 m dan selanjutnya dibuat sub plot berukuran 1 x 1 m sebanyak 5 sub plot. Setelah sampel terkumpul, selanjutnya dilakukan analisis kepadatan, hubungan panjang berat tubuh, struktur demografi, pola penyebaran spasial berdasarkan indeks Morisita dan karakteristik pertumbuhannya sebagai penciri khusus bila dibandingkan dengan T. telescopium di kawasan lain yang dianalisis menggunakan PCA. Hasil kajian memperlihatkan bahwa kepadatannya rendah (< 7 ind/m2), hubungan panjang beratnya allometrik negatif (b < 3), struktur demografi pertumbuhan yang dominan ditemukan tergolong dewasa (SL dominan 79.36 – 86.34 mm), pola penyebarannya mengelompok (Iδ = 02.75) dan morfometrik BT, BWL maupun AL sebagai penciri khususnya memiliki varian 95.91%.

Kajian kondisi eksisting tiram dilakukan pada tiga stasiun pengamatan di perairan estuari Desa Banda Masen (Juli – September 2020). Kajian bertujuan untuk mengetahui faktor lingkungan, distribusi dan biodiversitas, kepadatan, frekuensi pertumbuhan serta karakteristik lingkungan tiram, dimana sampel dikumpulkan dalam plot yang berukuran 1x1 m pada sisi kiri, tengah dan kanan estuari, sedangkan keterkaitan parameter kualitas perairan terhadap kepadatan maupun morfometrik tiram dianalisis berdasarkan Principle Component Analysis (PCA). Hasil kajian memperlihatkan bahwa konsentrasi DO berkisar antara 07,85–07,87 mg/L, suhu 30,00–32,00°C, salinitas 32,50–35,00‰, pH 07,90–08,13, kekeruhan 27,90–28,17 NTU, kecerahan 00,20–00,22 cm, kedalaman 01,20–01,27 m dan intensitas cahaya 449–452 Lux. Selain itu, hasil kajian juga memperlihatkan tiram terdistribusi di semua stasiun pengamatan, terdiri dari dua spesies dengan kepadatan S. cucullata antara 02,33–04,11 ind/m2 dan kepadatan S. echinata antara 02,11–03,56 ind/m2. Untuk frekuensi pertumbuhan morfometrik, panjang cangkang S. cucullata dominannya adalah 04,28–04,91 cm, lebar cangkang 03,48–04,06 cm, berat isi 03,18–04,85 mg dan berat cangkang 15,86–20,43 mg. Selanjutnya untuk frekuensi pertumbuhan morfometrik S. echinata, panjang cangkang dominannya adalah 03,82–04,27 cm, lebar cangkang 02,96–03,41 cm, berat isi 03,12–04,12 mg serta berat cangkang 15,06–19,33 mg, dimana kepadatan maupun berat isi S. cucullata sangat ditentukan oleh intensitas cahaya, salinitas, suhu dan kekeruhan perairan, sedangkan kecerahan perairan kurang memberikan pengaruh yang baik bagi kepadatan maupun berat isi tiram S. cucullata, kecuali bagi pertumbuhan panjang cangkang S. echinata, panjang cangkang S. cucullata, berat isi dan berat cangkang S. echinata.    The study of the existing condition of oysters was carried out at three observation stations in the estuary of Banda Masen Village during July until September 2020. The study aims to determine environmental factors, distribution, biodiversity, density, growth frequency and environmental characteristics of oysters. Samples were collected in plots with measuring 1x1 m on the left, middle and right sides of the estuary. Furthermore, the correlation parameters of water quality on density and morphometric of oysters to be analyzed base on Principle Component Analysis (PCA). The results showed that DO concentrations ranged between 07,85–07,87 mg/L, temperature 30,00–32,00°C, salinity 32,50–35,00‰, pH 07,90–08,13, turbidity 27,90–28,17 NTU, brightness 00,20–00,22 cm, depth 01,20–01,27 m and light intensity 449,00–452,00 Lux. In addition, the results of the study also depict that oysters were distributed in all observation stations which consisting of two species with density of S. cucullata and S. echinata between 02,33–04,11 ind/m2 and 02,11–03,56 ind/m2, respectively. The frequency of morphometric growth illustrates the dominant shell of S. cucullata was 04,28–04,91 cm in length, 03,48–04,06 cm in width, and 15,86–20,43 mg in weight with bulk have 03,18–04,85 mg in weight. Furthermore, the frequency of morphometrics growth of S. echinata have dominant shell was 03,82–04,27 cm in length, 02,96–03,41 cm in width, 15.06 –19,33 mg in weight with bulk have 03,12–04,12 mg in weight. The density and weight of the bulk of S. cucullata were largely determined by light intensity, salinity, temperature and turbidity of the waters. Meanwhile, the brightness did not give significant influence except for the length of two species and density also weight of S. echinata.

The phenomenon of marine debris can cause unrest among the community because it can cause marine pollution that affects the activities of coastal communities. This research was conducted with the aim of knowing the type, density and rate of increase of inorganic waste. The research location is at Ujong Blang Beach, Ujong Blang Village, Banda Sakti District, Lhokseumawe City on November 1-13 2021. The method used is purvosive sampling. The waste sampling technique uses a line transect method drawn from the shoreline along the 50 meters in the direction of the coastline and 10 meters towards the sea, in which there are 3 plots measuring 10x10 m2, the distance between the plots is 10 meters. The waste that is taken is waste that is on the substrate, the observed waste is macro-sized inorganic waste. The results showed that the garbage collected at Ujong Blang Beach, Ujong Blang Village, Banda Sakti District, Lhokseumawe City consisted of 5 types, namely plastic, metal, glass, rubber and clothing. Plastic waste has the highest density value, namely 1.59 items/m2 with a relative density value of 95.22%. The highest density value based on the mass of waste is also found in the type of plastic waste, which is 4.64 gr/m2 and a relative density of 78.64 %. The value of the highest rate of increase in waste was on Sunday with a total of 90.5 pieces of waste and a mass of 437.5 g of waste.