Mangrove is one of plants that can grow well on the coast which are affected by tides.Bone Baru village is located in North Banggai District, Banggai Laut Regency, Central Sulawesi Province which has area that about 840 ha and has mangrove area reaching 16.56 ha. This research was conducted from February to April 2020. The purpose of this research are to identify the types of mangroves and analyzing the structure of the mangrove community which include density, relative density, frequency, relative frequency, coverarge, relative coverage, importance value index, and diversity index. The data were analyzed using Microsoft Excel. Based on the results this study obtained 4 types of mangroves consisting of Bruguiera gymnorrhiza, B. cylindrica, Rhizophora mucronata, and Lumnitzera littorea. The highest relative density was 0.13 ind / m2 and the relative density was 91.83% the highest frequency type and the frequency relative value were 5 ind / m2 and 52.63%respectively. The highest mangrove cover was 3.79 m2 with relative cover of 52.21%. The highest important value index was 227.72% . The highest diversity index was found at station 2 with an average value (H ') of 0.69.Keywords: mangrove, community structure, habitat, BanggaiABSTRAKMangrove merupakan kelompok tumbuhan yang dapat tumbuh dengan baik di pesisir pantai yang dipengaruhi oleh pasang surut air laut. Penelitian ini dilakukan di desa Bone Baru, Kecamatan Banggai Utara, Kabupaten Banggai Laut, Provinsi Sulawesi Tengah yang memiliki luas wilayah mencapai 840 ha dan memiliki luas area mangrove mencapai 16,56 ha. Penelitian ini dilakukan dari bulan Februari-April 2020 dengan menggunakan metode Line Transect. Tujuan dari penelitian ini adalah mengidentifikasi jenis-jenis mangrove dan menganalisa struktur komunitas mangrove Data yang diambil meliputi kerapatan jenis, kerapatan relatif jenis, frekuensi jenis, frekuensi relatif jenis, penutupan jenis, penutupan relatif jenis, indeks nilai penting, dan indeks keanekaragaman yang kemudian di analisa dengan bantuan program komputer Microsoft Excel. Berdasarkan hasil penelitian ditemukan 4 jenis mangrove yaitu Bruguiera gymnorrhiza, Rhizophora mucronata, Lumnitzera littorea dan Bruguiera cylindrica. Kerapatan jenis tertinggi 0,13 ind/m2 dan kerapatan relatifnya 91,83%. Frekuensi jenis tertinggi dengan nilai 5 ind/m2 relatifnya 52,63%, penutupan jenis tertinggi dengan nilai 3,79 m2 dan relatfnya 52,21%, indeks nilai penting tertinggi dengan nilai 227,72% dan Nilai indeks keanekaragaman tertinggi ditemukan pada stasiun 2 dengan nilai ratarata (H’) 0,69.Kata kunci: mangrove, strukture komunitas, habitat, Banggai

Pemanasan global adalah salah satu isu di dunia saat ini, bisa dilihat dengan adanya peristiwa tingginya suhu bumi yang terkait langsung dengan gas-gas rumah kaca. Hutan mangrove dilaporkan mampu memitigasi pemanasan global karena kemampuannya menyimpan karbon di biomassa dan sedimen dengan baik. Telah dilakukan penelitian untuk mengetahui densitas sedimen tanah, presentase karbon organik, densitas karbon dan estimasi simpanan karbon pada sedimen ekosistem mangrove di Desa Baturapa Kecamatan Lolak Kabupaten Bolaang Mongondow. Pengambilan sampel sedimen mangrove dilakukan dengan teknik Purpose Sampling dan data yang diperoleh dianalisis dengan metode Loss on Ignition. Hasil penelitian menunjukan nilai rata-rata densitas tanah seluruh stasiun yaitu sebesar 0,39 g/cm3 ± 0,04. Nilai rata-rata presentase karbon organik pada seluruh stasiun yaitu sebesar 10,57 C% ± 4,87.Nilai rata-rata kandungan karbon total pada seluruh stasiun yaitu sebesar 398,82 MgC ha-1 ± 14,40. Hutan mangrove mampu menampung kandungan karbon dengan jumlah besar baik di biomassa dan sedimen.Kata Kunci : Analisis Stok Karbon, Sedimen Mangrove, Purpose Sampling, LOI (Loss On Ignition), Desa Baturapa, Kabupaten Bolaang Mongondow

The tsunami early warning system in Bitung does not work optimally, because there is no buoy as a marine equipment for tsunami validation before reaching the coastal area. The lack of buoy can be replaced by placing a tide gauge on the east coast of Lembeh Island. To determine the optimal tide gauge location, the simple additive weighting (SAW) method was used with three criteria. Those three criteria are the potential of tsunami detection, sufficient evacuation time, and an appropriate site for tide gauge installation. Numerical tsunami modeling is used to calculate the first two criteria. The third criterion is a limiting factor, because the tide gauge can only be installed on the dock. Therefore, there were only five candidate locations on the east coast of Lembeh, namely Dorbolang, Pancuran, Posokan, Motto, and Lirang. The result, Posokan is the best location for tide gauge placement with a total score of 2.884. Based on the simulation, an additional tide gauge in Posokan can detect tsunami at the average of 11.4 minutes earlier than use only the tide gauge currently available at Bitung port. It means that people on the coast of Bitung have more evacuation time before the tsunami hits the coastal area.

The study of the perception residents of the Siau island regarding the existence of sea turtles was carried out from June to December 2018. The survey method and direct observation were applied in data collection. The data collected then were analyzed descriptively. The results showed that 88 % of the residents are well acquainted with the life of sea turtles followed by 80 % of the residents knew of the sea turtles’ status as the protected animals through government regulations and international conventions. However, the proportion of residents involved in violating regulations are quite worrying to the survival of sea turtles. For it was found that 29% of the residents were catching sea turtles, 20 % were selling sea turtle meat and eggs, and 82 % were consuming sea turtle meat and eggs. Thefefore, law enforcement and conservation education are absolutely neccesary for the sustainability of sea turtles in North Sulawesi Indonesia. Keywords: Sea turtle, Siau Island, resident’s perception, law enforment. Conservation education  AbstrakTelaah presepsi warga pulau Siau terhadap keberadaan penyu laut telah dilaksanakan pada Juni-Desember 2018.  Metode survey dan observasi langsung diaplikasikan dalam pengumpulan data, dan data dianalisa secara deskripsif. Hasil menunjukkan bahwa warga mengenal dengan baik kehidupan penyu (88%) dan statusnya sebagai satwa yang dilindungi melalui regulasi pemerintah dan konvensi Internasional (80%). Namun proporsi warga yang terlibat dalam pelanggaran terhadap peraturan cukup mengkuartirkan akan keberlangsungan hidup penyu, yakni menangkap penyu (29%), menjual daging dan telur penyu (28%), mengkonsumsi daging dan telur penyu (82%). Penegakkan hukum dan edukasi diperlukan demi kelestarian penyu di Sulawesi Utara dan Indonesia pada umumnya.Kata kunci: Penyu laut, Pulau Siau, persepsi warga, penegakan hokum, pendidikan konservasi

The chemical elements making up the rocks located on the coastal areas in the Eastern Bolaang Mongondow were successfully mapped and investigated by employing the XRF method. The rocks collected from the Central Buyat, South Buyat, Motongkat and Jiko coastal areas of the sub-districts were milled until the size was close to 120 mesh. The samples were characterized and measured to obtain the chemical elements deposited inside the rocks. It was found that the elements which make up the rocks are relatively different depending on the coastal locations. The silicon (Si) was the highest percentage of all elements found and followed by iron (Fe), calcium (Ca) and aluminum (Al). The composition of Si deposited in the rocks from Buyat coastal area was of 42.4% which the biggest percentage compared the rest of the samples. The Iron (Fe) element had a chemical composition recorded at 28.9% that was the highest figure in which rocks were obtained from Jiko coast. The aluminum (Al) composition was relatively similar for all samples collected from that location and observed at 10%.

Bioactive compounds from the sea which are generally in the form of secondary metabolites have the potential to be developed as medicinal ingredients. Marine life can be used as an object of research and development, considering the many benefits that can be taken from the secondary metabolite compounds contained in it, especially compounds that have bioactivity. Soft corals are marine biota that have bioactivity, extracts from sost coral contain bioactive compounds that have cytotoxic, anti-tumor, anti-viral, anti-inflammatory, anti-fungal, anti-leukemic, and enzyme activity inhibitory properties. Some of the research results show that marine soft corals have a variety of structures and biological activities including antioxidant substances. Soft corals were extracted by maceration method and then evaporated. The cytotoxic activity of soft coral extract was tested using the BLSA method and then analyzed the data to find the concentration of mortality (LC50). The purpose of this study was to test the cytotoxic activity of soft coral Xenia sp. The results of this study were testing the cytotoxic activity of the sample Xenia sp., amounting to 20.89 ppm, and having strong toxic properties. Key words: BLSA, Soft coral Xenia sp., LC50, Cytotoxic

Sejak era 1990anpembangunan di Kota Manado mulai difokuskan di wilayah pesisir. Kegiatan reklamasimemberikan dampak terhadap pergerakan massa air terutama di kawasan pantai padaskala tertentu.   Pemantauan secara berkala terhadap kondisi oseanografiskawasan pantai sekitar lahan reklamasi dipandang penting dilakukan untuk mencermatisejauh mana perubahan telah terjadi dengan menentukan arah dan kecepatan arus sertamenganalisis dinamika arus yang berlaku saat bulan kuartir akhir dan bulan purnama.  Denganmenerapkan metode lagrangian ditemukan beberapa hal penting terkaitkarakteristik arus yang berlaku pada kawasan yang diobservasi.  Pada periode bulan kuartir akhir, kecepatanresultan arus yang terukur saat surut dan pasang bervariasi diantara 0,70sampai 1,40 knot. Saat surut arus mengarah ke Barat dan Barat Laut sedangkansaat pasang mengarah ke Barat dan Barat Daya. Pada periode bulan Purnama  kecepatan resultan arus yang terukur saatsurut dan pasang bervariasi diantara 0,70 sampai 1,09 knot.  Saat surut umumnya arus mengarah ke BaratLaut dan Utara, berbeda  dengan waktupasang dimana arah arus ke Barat.  Araharus di perairan Sario Tumpaan saat pergerakan air pasang dan surut selalumengarah ke laut dengan arah relatif ke Barat Daya,  Barat dan Barat Laut.

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