Vertical Distribution of Nutrients on Transitional Season in Weda Bay, North Maluku

A vertical distribution of nutrient shows an interaction of physical processes, source, and uptake along the water column. These interactions can occur along the water column with different processes in each layer. Water samples from 17 stations were collected for nitrate, phosphate, and silicates concentration analyses during the transitional season in the Weda Bay. During the transitional season, the Weda Bay was characterized by low salinity (33.55-34.10), relatively warm temperature (30.87°C), and the relatively low nutrient concentrations (nitrate=0.03-4.87 µg at/l, phosphate=0.011-0.852 µg at/l, and silicate=0.04-1.21 µg at/l). The present of Western North Pacific Ocean (WNPO) watermass and the influence of Southern Subtropical Lower Water (SSLW) producing high salinity (>35) at the depth of 130-300 m were observed along the Weda Bay. Nutrient geochemical processes in this region were shown by nutrient utilization and regeneration across the water columns. Nutrients utilization was relatively high in the surface layer. Meanwhile, nutrients regeneration and remineralization were more dominant in the thermocline and deeper water layers. Analyses of nutrients showed that nitrate was more dominant than other nutrients with N/P ratio was 3.83-37.99 and N/Si ratio was 0.12-10.98. The effectiveness of silicate (0.25 μg at/l) that was used by phytoplankton found at a depth of 200 m when its concentration decreased at N/P ratio (16:08) close to the Redfield ratio. Due to an uptake, remineralization, and regeneration processes in each layer, a nutrient distribution pattern was formed which the nutrient concentrations decreased in mixed layer and increased in the deeper water

VERTICAL DISTRIBUTION OF NUTRIENTS ON TRANSITIONAL SEASON IN WEDA BAY, NORTH MALUKU

A vertical distribution of nutrient shows an interaction of physical processes, source, and uptake along the water column. These interactions can occur along the water column with different processes in each layer. Water samples from 17 stations were collected for nitrate, phosphate, and silicates concentration analyses during the transitional season in the Weda Bay. During the transitional season, the Weda Bay was characterized by low salinity (33.55-34.10), relatively warm temperature (30.87°C), and the relatively low nutrient concentrations (nitrate=0.03-4.87 µg at/l, phosphate=0.011-0.852 µg at/l, and silicate=0.04-1.21 µg at/l). The present of Western North Pacific Ocean (WNPO) watermass and the influence of Southern Subtropical Lower Water (SSLW) producing high salinity (>35) at the depth of 130-300 m were observed along the Weda Bay. Nutrient geochemical processes in this region were shown by nutrient utilization and regeneration across the water columns. Nutrients utilization was relatively high in the surface layer. Meanwhile, nutrients regeneration and remineralization were more dominant in the thermocline and deeper water layers. Analyses of nutrients showed that nitrate was more dominant than other nutrients with N/P ratio was 3.83-37.99 and N/Si ratio was 0.12-10.98. The effectiveness of silicate (0.25 μg at/l) that was used by phytoplankton found at a depth of 200 m when its concentration decreased at N/P ratio (16:08) close to the Redfield ratio. Due to an uptake, remineralization, and regeneration processes in each layer, a nutrient distribution pattern was formed which the nutrient concentrations decreased in mixed layer and increased in the deeper water.Keywords:nutrien, pattern, Weda Bay, transitional season

ALTERNATIVE MEASURING OF DISSOLVED OXYGEN IN THE WESTERN INDONESIAN SEAS DURING SOUTHEAST MONSOON

Pengukuran oksigen terlarut dengan metode Winkler memiliki kelemahan, namun bisa diatasi dengan metode spektrofotometri. Tujuan dari penelitian ini adalah mengukur konsentrasi oksigen terlarut berdasarkan metode spektrofotometri di bagian barat laut Indonesia pada muson tenggara Juni 2015. Konsentrasi oksigen diukur berdasarkan hukum Lambert-Beer dengan panjang gelombang 466 nm. Hasil pengukuran menunjukkan bahwa konsentrasi oksigen tinggi di bagian barat Selat Karimata dan rendah pada bagian tengah selat yang dimungkinkan karena tingginya proses oksidasi bahan organik dan respirasi. Konsentrasi oksigen cenderung seragam di seluruh kolom air Laut Jawa bagian barat, hal tersebut mencerminkan proses pencampuran sempurna. Konsenstrasi yang sama juga terlihat jelas pada lapisan permukaan di Selat Sunda dan berkurang dengan bertambahnya kedalaman. Laut Indonesia bagian barat cenderung supersaturasi pada lapisan permukaan dan mengindikasikan adanya pertukaran yang cepat antara oksigen pada lapisan permukaan air laut dengan atmosfer. Hasil korelasi pengukuran oksigen antara metode spektrofotometri dan sensor menunjukkan hubungan yang baik sehingga dapat dijadikan alternatif dalam mengukur konsentrasi oksigen terlarut dan dapat digunakan pada berbagai rentang konsentrasi oksigen yang luas di wilayah laut, air tawar, dan pesisir.The measurement of dissolved oxygen (DO) using the Winkler method has weaknesses, but can be solved by the spectrophotometric method. The purpose of this study was to measure the concentration of dissolved oxygen based on the spectrophotometric method in the western Indonesian Seas during the southeast monsoon of June 2015. The concentration of DO was measured according to the Lambert-Beer law using a wavelength of 466 nm. The results show that the oxygen concentration is high in the western of the Karimata Strait and low in the middle of the strait due to respiration and oxidation of organic matter. The oxygen concentration tends to be homogenous the entire of water column of western part of the Java Sea which indicates water well mixed and their concentration in the surface layer of the Sunda Strait was similar and gradually decreased with depth. The western Indonesian Seas is generally oversaturated corresponding to a quick oxygen air-sea water exchange. The results of the correlation of oxygen measurements between the spectrophotometric method and the sensor show a good performance, so that it can be used as an alternative in measuring dissolved oxygen concentrations and can be used over a wide range of oxygen concentrations in oceanic, fresh water and coastal areas

PERGERAKAN ZONA KONVERGENSI DI SAMUDERA PASIFIK BAGIAN BARAT BERDASARKAN DATA INSITU DAN SATELIT

Samudera Pasifik berperan penting dalam siklus El-Nino Southern Oscillation (ENSO) dan berpengaruh signifikan pada kegiatan penangkapan tuna di Indonesia, khususnya ikan Cakalang. Penelitian ini bertujuan mengetahui pola pergerakan zona konvergensi di Samudera Pasifik bagian Barat dengan mengamati pergerakan parameter oseanografi seperti suhu, salinitas, klorofil-a, dan produktivitas primer. Data parameter oseanografi tersebut terdiri dari data insitu, data satelit maupun hasil pemodelan. Hasil analisis menunjukan adanya pergerakan zona konvergensi di Barat Pasifik yang dicirikan variabel proksi yaitu isotermal 29°C, isohalin 34,6 psu, konsenrasi klorofil-a sebesar 0,1 mg/m3 dan NPP 300 mgC/m2/day. Pola pergerakan zona konvergensi baik secara horisontal maupun vertikal dipengaruhi oleh ENSO. Pada saat terjadi La-Nina massa air dengan suhu yang hangat bergeser ke arah Barat yang diikuti dengan meningkatnya kesuburan perairan. Pergerakan vertikal massa air hangat terjadi pada kedalaman 25-75 m (suhu) dan 50 m (salinitas). Namun pada saat El-Nino massa air hangat bergerak ke arah Timur Samudera Pasifik. Fluktuasi produksi tangkapan ikan Cakalang di perairan Indonesia Timur mengikuti pola pergerakan zona konvergensi tersebut. Peningkatan jumlah produksi ikan Cakalang di Kota Sorong meningkat seiring dengan keberadaan zona konvergensi di bagian Barat (La-Nina), namun di Propinsi Papua menunjukan pola sebaliknya

BAKTERI ASOSIASI PADA KARANG SCLERACTINIA KAITANNYA DENGAN FENOMENA LA-NINA DI PULAU BUNAKEN

Penelitian tentang karang keras (Scleractinian coral) yang terkontaminasi bakteri relatif masih kurang dilakukan khususnya di perairan Indonesia. Untuk itu dilakukan kegiatan penelitian di Taman Nasional Bunaken pada dua periode yakni Mei 2010 (musim peralihan I)  dan Agustus 2011 (Monsoon II). Penelitian ini difokuskan pada kontaminasi bakteri gram positif (+) dan gram negatif (-). Metode yang dilakukan untuk pengambilan sampel di lapangan adalah time swim dimana menyelam  pada kedalaman 5-10 meter selama kurang lebih 30 menit dan mengambil sampel mucus karang secara acak/random dengan menggunakan siring atau mengambil sampel secara langsung pada karang (fraksi cabang) pada lokasi yang sama. Sampel dianalisis dengan proses isolasi bakteri di laboratorium. Hasil penelitian menunjukkan bahwa pada  Mei 2010 bakteri gram positif lebih mendominasi dari gram negatif, sebaliknya Agustus 2011 bakteri gram negatif yang lebih dominan dari gram positif.  Indikasi faktor penyebab terjadinya bakteri gram positif yang lebih dominan khususnya di tahun 2010  ialah fenomena La-Nina yang terjadi selama periode tersebut. Perubahan suhu rata-rata yang terjadi pada kedua musim tersebut menjadi salah satu faktor yang merangsang pertumbuhan kedua kelompok bakteri ini.  Perlu dilakukan penelitian lebih lanjut khususnya dalam menentukan jenis bakterinya dan pengambilan sampel pada setiap musim

PROFIL VERTIKAL KANDUNGAN OKSIGEN TERLARUT DAN FLUORESENCE IN VIVO SEBAGAI INDIKATOR KEBERLANGSUNGAN KEHIDUPAN DI PERAIRAN LAUT MALUKU DAN LAUT SULAWESI

Indeso Joint Expeditions Cruise (IJEP) activity in 2016 measured some water quality parameters, one of them are dissolved oxygen and in vivo fluorescence for expressing biomass of phytoplankton community.Those parameters were measured for analyzing the important component of marine biogeochemical cycle used the titrimetric method and optical sensor.  Expedition of  IJEP was conducted on September 5-15, 2016 from the port of P2LD-LIPI Ambon into Bitung port, North Sulawesi. Measurement results of Dissolved Oxygen (DO) at 21 stations showed varied values vertically and horizontally.  Vertical distribution of DO and fluorescence were measured at seven of depth water (10, 50, 60-150, 300, 500, 750 dan 1000 meter).  Distribution of DO decreased through ocean inventory with its range values was 3,334 – 7,321 mg/L.  Depletion of dissolved oxygen from surface layer into the upper of thermocline layers (50 – 400 meter).  The concentration of DO decreased after chlorophyll maximum layer (represent as in vivo fluorescence) at different of depth water with its range value was 0,4441 – 1,1376 mg/m3. The concentrations of dissolved oxygen were higher both vertically and horizontally in Sulawesi Sea than in Maluku Sea at this transitional season (September 2016) but inversely condition for the in vivo fluorescence in which it’s higher in Maluku Sea. There was an indication of internal upper water mass impacts on the highest concentration of in vivo fluorescence in Maluku Sea. These results indicate that Maluku Sea and Sulawesi Sea have the carrying capacity of the ecosystem for sustainability of their marine life.

BAKTERI PADA KARANG SCLERACTINIA DI KAWASAN PERAIRAN BUNAKEN, MOROTAI DAN RAJA AMPAT

Research on hard coral (Scleractinian coral) contaminated with bacteria is still not much done, especially in Indonesian waters. This study took samples of coral mucus in 2010 at 3 (three) different locations, namely Bunaken (May); Morotai (September) and Raja Ampat (November), which focused on the analysis of Research on hard coral (Scleractinian coral) contaminated with bacteria is still not much done, especially in Indonesian waters. This study took samples of coral mucus in 2010 at 3 (three) different locations, namely Bunaken (May); Morotai (September) and Raja Ampat (November), which focused on the analysis of gram-positive and gram-negative bacteria. The method used for field sampling is time swim, which is by diving at a depth of 5-10 meters for ± 30 minutes and randomly taking samples of coral mucus using siring or by taking directly on corals (reef branching). Mucus samples were analyzed by bacterial isolation in the laboratory. The result shows that there were differences between gram-positive and gram-negative bacteria in the three research sites and that gram-positive bacteria were higher or dominant. Further research that can identify the bacteria species and explain its relationship to the ecosystem is highly recommended.Keywords: Bacteria, Scleractinian coral, gram-positive and -negative, Bunaken, Morotai, Raja Ampat                                               AbstrakPenelitian tentang karang keras (Scleractinian coral) yang terkontaminasi bakteri masih belum banyak dilakukan, terutama di perairan Indonesia. Penelitian ini mengambil sampel mucus karang pada tahun 2010 di 3 (tiga) lokasi berbeda, yakni Bunaken (Mei); Morotai (September) dan Raja Ampat (November), yang difokuskan pada analisis bakteri gram postif dan gram negatif. Metode yang digunakan untuk pengambilan sampel di lapangan adalah time swim, yaitu dengan penyelaman pada kedalaman 5-10 meter selama ±30 menit dan mengambil sampel mucus karang secara acak menggunakan siring atau dengan mengambil langsung pada karang (fraksi cabang). Sampel mucus dianalisis dengan cara isolasi bakteri di laboratorium. Hasil analisis menunjukkan bahwa ada perbedaan antara bakteri gram positif dan gram negative di tiga lokasi survei dan bakteri gram positif lebih tinggi atau dominan. Penelitian lebih lanjut yang dapat menentukan jenis bakteri serta menjelaskan hubungannya dengan ekosistem sangat disarankan untuk dilakukan.Kata Kunci : Bakteri, Scleractinian coral, gram positif dan negatif, Bunaken, Morotai, Raja Ampa

Analisa Bakteri pada Karang Scleractinia Berkaitan dengan Fenomena La-nina di Kawasan Taman Nasional Bunaken

Research about Scleractinian Coral with bacteria contamination are relatively new explore in Indonesia. The research study was located in Bunaken National Park in period May 2010 and August 2011. Research focused on gram positive ( +) and gram negative (-) bacteria. For sampling procedure by using SCUBA equipment with time swim at depth 5 - 10 meters at least 30 minutes and collected randomly coral mucus. In the Laboratory sample anlayzed by Isolate bactery process. For the result we noticed that on May 2010 gram positive bacteria are dominant, otherwise in August 2011 gram negative bacteria more dominant. Were indicated influence by La-Nina phenomenon during 2010 until earlier 2011 that seasonal transition I (May) and Monsoon II (August) is sigfnificantly different. For the future need to be explore especially to determine species of bactery and seasonal sampling

Sea bunnies as a potential marine ecotourism in sumberkima, Buleleng Regency, Bali

The Sumberkima Village has a vital coral reef ecosystem since the ecosystem has become home to some incredible marine biotas, including sea bunnies, a sea slug or Nudibranch species. The Nudibranch community can indicate the health of the ecosystem from its diversity and structure. This study aims to determine the distribution and value of the Nudibranchia Ecological Index and provide an example informative infographic of sea bunnies to support marine ecotourism at Sumberkima Village, Gerokgak District, Buleleng Regency, Bali Province. The research method applied is observation by visual census with an underwater camera (underwater visual census) and SCUBA diving equipment at a depth range of 5-25 meters. Observation data were collected in April 2021. A total of 15 species were found at ten dive sites.: Chromodoris annae, Chromodoris magnifica, Goniobranchus reticulatus, Hypselodoris apolegma, Hypselodoris bullockii, Nembrotha cristata, Nembrotha kubaryana, Nembrotha sp, Notodoris serenae, Phyllidia elegans, Phyllidia varicosa, Phyllidiopsis pipecki, Phyllidiopsis shireenae. The most dominant species was a member of Phyllidia genus, and an uncommon species is Goniobranchus reticulatus