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All Journal Jurnal Ilmu dan Teknologi Kelautan Tropis Indonesian Journal of Geography Journal of Marine and Aquatic Sciences Buletin Udayana Mengabdi Ecotrophic, Journal of Environmental Science REKAYASA INDONESIAN JOURNAL OF APPLIED PHYSICS Jurnal Geografi Journal of Marine Research and Technology International Journal of Remote Sensing and Earth Sciences (IJReSES) INTERNATIONAL JOURNAL OF ENVIRONMENT AND GEOSCIENCES International Journal of Environmental, Sustainability, and Social Science The International Journal of Remote Sensing and Earth Sciences (IJReSES)

I Wayan Gede Astawa Karang

Faculty Of Marine Science And Fisheries, Udayana University, Bukit Jimbaran, Bali 80361

Author-ID : 519235

Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Computer Science & IT Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Library & Information Science Materials Science & Nanotechnology Physics Social Sciences Other

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Hubungan Klorofil-a dan Suhu Permukaan Laut (SPL) Terhadap Hasil Tangkapan Ikan Lemuru Sardinella lemuru di Selat Bali Menggunakan Citra Aqua MODIS Tahun 2009-2018 Rony Clinton; I Wayan Gede Astawa Karang; Widiastuti Widiastuti
Journal of Marine Research and Technology Vol 5 No 1 (2022): FEBRUARI 2022
Publisher : Department of Marine Sciences, Faculty of Marine Science and Fisheries, Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2022.v05.i01.p08

Oceanographic parameters such as sea surface temperature (SST) and chlorophyll-a in the water can influence the productivity of pelagic fish such as Lemuru. Many studies have been conducted on the relationship between SST and chlorophyll-a and the fluctuations in the catch of Lemuru fish, especially using satellite databased sensing technology. Most of the research using satellite data is done in a short-term period (not climatology), so there are still a lot of unanswered questions. One of them is: how the correlation between the fluctuation in the number of Lemuru fish catches is related to SST and chlorophyll-a in the ENSO and IOD periods. The purpose of this study is to determine the distribution of SST and chlorophyll-a concentrations and their relationship with the yield of Lemuru fish catches in the Bali Strait from 2009 to 2018. Aqua Moderate Imaging Spectroradiometer (MODIS) satellite data level 2 from Oceancolor and data on the number of fish caught in the Bali Strait from the National Fisheries Port (PPN) Pengambengan and UPT PPP Muncar. The method is used with correlation analysis between SST and chlorophyll-a to the number of Lemuru fish caught. The monthly average SST in Bali Strait waters from 2009 to 2018 was approximately 24,76 0C-30, 11 0C, with an estimated monthly chlorophyll-a concentration of 0,10 mg/m3-3,68 mg/m3. The spatial distribution of SST tends to be low in the southern Bali Strait and tends to be high in the northern Bali Strait. The spatial distribution of chlorophyll-a appears to have a high value in the near land area. The cross-correlation test between chlorophyll-a and the number of Lemuru catches showed a positive correlation yield at the 4th month lag. While the correlation of SST to the number of Lemuru fish catches shows a positive correlation at lag (-1).

Studi Karakteristik Suhu Permukaan Laut (SPL) Di Perairan Selat Lombok Menggunakan Citra Satelit EOS Aqua MODIS Fitra Cahya Prima; I Wayan Gede Astawa Karang; I Gede Hendrawan
Journal of Marine Research and Technology Vol 4 No 2 (2021): AGUSTUS 2021
Publisher : Department of Marine Sciences, Faculty of Marine Science and Fisheries, Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2021.v04.i02.p04

The Lombok Strait is a strait located between Lombok Island and Bali Island which connects the waters of the Bali Sea to the Indian Ocean, whose SST conditions vary with oceanographic-atmospheric conditions in the Indian Ocean and the Pacific Ocean. This research aims to determine the temporal and spatial SST in the North and South Lombok Strait. Therefore, this study divides the Lombok Strait area into two because of the influence of the Pacific Ocean and the Indian Ocean. The method used in this research is descriptive and statistical analysis. The highest average monthly SST in the northern and southern Lombok Strait occurred in April at 29.11 °C and the lowest in August at 26.82°C. For the average seasonal SST, the highest occurred at transition I of 28.86°C, and the lowest occurred in the eastern season at 27.39°C. The highest average annual SST occurred in 2010 at 28.83°C and the lowest occurred in 2018 at 27.69°C. The northern SST anomaly has the same fluctuation as ENSO with inversely proportional IOD. Southern SST anomaly has fluctuation which is inversely proportional to ENSO and IOD. The correlation between SST anomaly in the north and ENSO correlates 0.90 (very strong), while with IOD it correlates 0.12 (very low). The correlation between SST anomaly in the southern part and ENSO correlates -0.11 (very low), while with IOD it correlates -0.73 (strong)

Estimasi Stok Karbon Di Atas Permukaan Menggunakan Citra Sentinel-1A di Hutan Mangrove Karang Sewu, Bali Nikmah Fitria Nuraini; I Wayan Gede Astawa Karang; I Nyoman Giri Putra
Journal of Marine Research and Technology Vol 5 No 1 (2022): FEBRUARI 2022
Publisher : Department of Marine Sciences, Faculty of Marine Science and Fisheries, Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2022.v05.i01.p05

Karang Sewu mangrove is one of the forests in the tropics that can store a higher amount of carbon compared to other forest. The researh of carbon storage in the Karang Sewu mangrove forest is required to support government policies in mitigating blue carbon. Research about above ground and below ground carbons in the Karang Sewu mangroves has not provided spatial information, and one of the techniques that can be used is remote sensing with Synthetic Aperture Radar (SAR). This research used SAR Sentinel-1A C-Band sensor imagery to estimate above-ground carbon in mangroves because it can penetrate the canopy to branch vegetation so that the backscatter value is not disturbed by water on the surface. The purpose of this study was to determine the above-ground carbon value in the mangrove forest Karang Sewu, Bali, using Sentinel-1A imagery. Estimation of above-ground carbon in SAR images using the sigma nought Vertikal Horizontal polarization method based on carbon estimation models from field data and image data. The best carbon estimator model is a polynomial model with the equation y = 0.1055x2 + 4.1507x + 43,691, R2 = 0.3347. The Root Mean Square Error (RMSE) error rate is 0,7. Based on the RMSE value, it can be concluded that the difference between the field carbon and the image carbon results is relatively small The estimation result of the total above-ground carbon value using Sentinel-1A imagery is 59.85 tons/ha.

Hubungan Rugositas Terumbu Karang terhadap Struktur Komunitas Ikan Corallivor dan Herbivor di Perairan Pemuteran, Bali Nidzar Muhammad Rafly; I Wayan Gede Astawa Karang; Widiastuti Widiastuti
Journal of Marine Research and Technology Vol 3 No 1 (2020): FEBRUARI 2020
Publisher : Department of Marine Sciences, Faculty of Marine Science and Fisheries, Udayana University

Reef fishes are the highest number of organisms that can be found in coral reefs in which the abundance depends on the healthy of this ecosystem. Reef fishes are mainly consisted of corallivorous and herbivorous fish. Corralivorous fish feeds on coral polyps while herbivorous fish feeds on algae. Therefore these fishes are an important indicators in the resilience of coral reefs. Studies showed that its abundance is strongly correlated with reef’s conture (rugosity). Pemuteran waters is one of developing tourists attraction in the north Bali island. However, the data of reef fishes and coral reefs in Pemuteran waters remain limited. Therefore, this research aimed to study the reef` condition and rugosity in Pemuteran waters, also to examine the correlation between reefs fishes and reefs rugosity in this area. There were four stations according to purposive sampling method. Data of corallivorous and herbivorous fishes were collected by using the underwater visual census with a 40 m2 transect. Reef rugosity index were determined by using chain transect method. Results showed that reef rugosity in Pemuteran waters was in the medium to high category. Reef rugosity has strong correlation with the total abundance and diversity of corallivorous fishes. However, reef rugosity was only strong correlated with the total abundance but not with the diversity of herbivorous fishes.

Struktur Komunitas Makroalga Di Perairan Tenggara Pulau Serangan, Bali Ni Luh Putu Ayu Sumarni; I Wayan Gede Astawa Karang; Widiastuti Karim
Journal of Marine Research and Technology Vol 2 No 2 (2019): AGUSTUS 2019
Publisher : Department of Marine Sciences, Faculty of Marine Science and Fisheries, Udayana University

Macroalgae is one of the biota that is found in all Indonesian waters. Macroalgae has an important role in marine ecosystems, namely as producers, ingredients and pharmacy. The purpose of this research was to determine the community structure of macroalgae. The community structures were measured by using a square transect of 1x1 m2 within a 50 m2 squared transect. Thus macroalgae were determined for its density, diversity, biomass and distribution. The differences among community structures at each station were analyzed by using the One-way Anova. The results showed that the macroalgae were classified into red, brown and green macroalgae. The highest macroalgae density wasw 21 ind/m2 and the lowest was 8 ind/m2. The diversity of macroalgae was in the medium category which the most dominant was red macroalgae. It is likely due to different ability to get the nutrients among macroalgae. The highest biomass was found in the red macroalgae while the lowest was in the green macroalgae. It might be related to the large size and weight of the thallus of red macroalgae. The One-way Anova analysis showed that there was a significant difference in macroalgae density and biomass at each station.

Struktur Komunitas Echinodermata pada Musim Barat dan Musim Peralihan I di Ekosistem Lamun Perairan Tanjung Benoa, Bali Anak Agung Istri Candra Kirana; Elok Faiqoh; I Wayan Gede Astawa Karang
Journal of Marine and Aquatic Sciences Vol 7 No 1 (2021)
Publisher : Fakultas Kelautan dan Perikanan Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/jmas.2021.v07.i01.p16

Echinoderms in marine ecology have a role as deposit feeders. This shows the diversity of the Echinoderms phylum found in seagrass ecosystems. Seagrass beds serve as protection and a source of nutrients that maintain the food chain. Tanjung Benoa waters are located in the waters of South Bali which has a seagrass ecosystem. Echinoderms as invertebrate animals can be influenced by abiotic factors, namely salinity and temperature which are affected by the season. This study aims to determine changes in the structure of the Echinodermata community in the western and transitional seasons I in seagrass ecosystems and determine the environmental factors that influence the structure of the Echinoderms community in the waters of Tanjung Benoa. Echinoderms data collection method used is the Underwater Visual Census (UVC) method. Data is taken by using purposive sampling technique. The results showed that in both seasons, the western season and the transitional season I, the phylum of Echinoderms found consisted of 4 classes namely Holothuroidea, Ophiuroidea, Echinoidea and Asteroidea. The diversity index and uniformity of the Ecinodermal phylum found in both seasons shows stable diversity and uniformity. Based on the index of dominance there is one genus that dominates, namely the genus Diadema. Based on the analysis of PCA in the west season, the density of Echinoderms is influenced by phosphate, nitrate, DO, salinity, pH and temperature. Whereas in the transitional season I density is influenced by phosphate, salinity, temperature, nitrate and pH.

Potensi Harmful Algae Bloom (HAB) di Keramba Jaring Apung Perairan Desa Sumberkima Kecamatan Gerokgak, Kabupaten Buleleng Ni Luh Kade Paramita Kusuma; I Wayan Gede Astawa Karang; I Gusti Bagus Sila Dharma
Journal of Marine and Aquatic Sciences Vol 7 No 2 (2021)
Publisher : Fakultas Kelautan dan Perikanan Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/jmas.2021.v07.i02.p15

Sumberkima Village is one of the villages in Gerokgak sub-district that has the most floating net cage cultivation in Buleleng regency. The development of fish farming activities with floating net cage techniques had an impact on the waters. The leftover feed that is not consumed, and the metabolic wastes produced by aquaculture increased the fertility of the waters so that it is feared that phytoplankton are potentially causing the Harmful Algae Bloom (HAB) phenomenon in the floating net cage aquaculture area of Sumberkima village which can have an impact on water quality, aquatic biota and cultivator’s income. This study aimed to identify the genus phytoplankton that has the potential to cause Harmful Algae Bloom (HAB) and the abundance of phytoplankton that has the potential to cause the Harmful Algae Bloom (HAB) phenomenon. This research was conducted in February 2019 at the floating net cage in Sumberkima village, Gerokgak sub-district, Buleleng regency. The study was spread over 10 points of floating net cages determined by purposive random sampling to represent floating net cages in Sumberkima village. Data were analyzed descriptively with phytoplankton abundance calculation using APHA (2005) method. From the research that has been done, it was found that the type of phytoplankton suspected to have HAB potential was found in 2 class groups namely Dinophyceae with a percentage of 15% consisting of: Prorocentrum, Dinophysis, Alexandrium and Peridinium then Bacillariophyceae with a percentage of 85% as many as 7 genera include: Thalassiosira, Pseudonitzschia, Biddulphia, Nitzschia, Skeletonema, Chaetoceros and Ceratium.

Pemetaan Habitat Dasar Perairan Dangkal Menggunakan Citra Satelit SPOT-7 di Pulau Nusa Lembongan, Bali I Dewa Made Krisna Putra Astaman; I Wayan Gede Astawa Karang; I Gede Hendrawan; Kuncoro Teguh Setiawan
Journal of Marine and Aquatic Sciences Vol 7 No 2 (2021)
Publisher : Fakultas Kelautan dan Perikanan Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/jmas.2021.v07.i02.p07

Shallow water habitat is one of the regions that has high dynamics and has an important role are ecologically and economically. The high dynamics of the ideal shallow water habitat is always followed by updating information so that an overview of the area is obtained in accordance with reality. Remote sensing technology is one of the technologies that can be used for mapping natural resource studies such as mapping of shallow water habitats with the satellite imagery. This study aims to map the distribution of shallow water habitats using SPOT-7 satellite imagery on Nusa Lembongan Island, Bali and test the level of accuracy. The method used true color composite and DII (Depth Invariant Index) transformation and uses the maximum likelihood classification. The classification scheme used 6 classes, namely sand, seagrass, macro algae, rubble, live coral, and dead coral. The results of this study indicate the distribution of shallow water habitat on Nusa Lembongan Island, Bali spread equally based on the level of water depth with a total area of shallow water habitat of 453.41 ha. The results of mapping accuracy test showed the overall accuracy of the DII transformation classification results is better than the composite image classification results with an overall accuracy of 75.43% and a kappa coefficient is 0.71. So from these results can be said that used of a water column correction with the DII method can improve image accuracy in mapping shallow water habitats.

ESTIMASI SIMPANAN KARBON PADA BIOMASSA MANGROVE DI TAHURA NGURAH RAI Ni Luh Putu Ratih Pravitha; I Wayan Gede Astawa Karang; Made Suartana
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 16 No 2 (2022)
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/EJES.2022.v16.i02.p08

Mangroves contribute to mitigating climate change by storing carbon. As mangrove forests have a high rate of carbon sequestration and storage, carbon stock calculations are required to quantify the accumulation of carbon stored in a site to determine its involvement in decreasing greenhouse gas emissions. This study aims to estimate carbon storage at the Mangrove Information Center (MIC) by using an allometric calculation of the mangrove above-ground biomass data. Data collection was carried out on January 10-14, 2022 at the MIC, with an area of 322 ha. The method used is a 1000 meters line transect plot divided into 15 measuring plots in three mangrove ecological zones (front, middle, and back). Biomass data were taken in a non-destructive way based on measurements of the circumference girth at breast height (GBH) and the results were calculated using allometric. According to data analysis, the average total surface biomass of mangroves in MIC is 781.30 kg, with estimated carbon storage in MIC is 36,727 tons/ha. Overall, the total carbon stock in the stratum MIC is 11.826,253 tons. The highest estimated carbon storage is in Plot 9, which is 91,799 tons/ha, while the lowest estimated carbon storage is in Plot 2, which is 13,873 tons/ha. The high numbers of carbon storage from mangrove above-ground biomass are mostly found in the middle and front zones because of the very dense mangrove density. Keywords: mangrove; above-ground carbon estimation; climate change mitigation

Analisis Kecepatan Perambatan Gelombang Internal Soliter di Selat Lombok dengan Citra Himawari-8 Chonnaniyah Chonnaniyah; I Wayan Gede Astawa Karang; Abd. Rahman As-syakur; Takahiro Osawa
Journal of Marine and Aquatic Sciences Vol 8 No 1 (2022)
Publisher : Fakultas Kelautan dan Perikanan Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/jmas.2022.v08.i01.p04

Internal waves are phenomena that occur below sea surface. One of the most observed types of internal waves was called a solitary wave or soliton so it is often known as an internal solitary wave (ISW). Lombok Strait was one of the straits located in the southern part of the Indonesian archipelago which has the characteristics of intensive ISW generation because this strait has complex waters characteristics. This study aim to analyzed in detail the changes in the ISW propagation speed at the first crest soliton every 10 minutes using Himawari-8 data. The detected ISW pattern is then extracted at the first crest of the soliton as a reference to measure the distance between the detected soliton every 10 minutes as input in estimating the propagation speed. The Himawari-8 image which was in this study detected 2 ISW packets in the Lombok strait area. Packet 1 which was detected in the northern part of the Lombok strait approaching Kangean island had a group speed of 2.22 m/s and Packet 2 which was detected in the area around the Lombok strait had a group speed of 2.78 m/s. The difference in group velocity of the two packets is due to the variation in depth along the ISW propagation. The analysis results of changes in ISW propagation speed in this study indicate that Himawari-8 imagery is a very effective instrument for analysing changes in ISW propagation speed in detail every 10 minutes which is difficult for satellite imagery which usually has low temporal resolution.

Co-Authors Abd. Rahman As-syakur Alexis Chappuis Anak Agung Istri Candra Kirana Anisa Dea Novianti Artha C. Rosevina Anak Ampun Astaman, I Dewa Made Khrisna Putra Astiti Ratnasari Astiti Ratnasari Azhar Muhammad Hanisa Brasika, Ida Bagus Mandhara Chonnaniyah Chonnaniyah Chonnaniyah, Chonnaniyah Cindi Ayu Lestari Cornelia Coraima Lazaren Dian Novianto Dwi Budi Wiyanto Dwi Nindra Saputra Eka Andiani, Anak Agung Elok Faiqoh Elvita Rahmani Fitra Cahya Prima Fumihiko Nishio Gede Dicky Pradipta Wedayana Gede Indra Putra Pratama Gede Surya Indrawan Gilang Pratama I Dewa Ayu Ratna Raksa Eka Putri I Dewa Nym. Nurweda P., I Gede Andika Wijantara I Gede Hendrawan I Gede Merta Yoga Pratama I Gede Mita Anjas Swara I Gusti Agung Bagus Wisesa Sastra I Gusti Agung Indah Mahasani I Gusti Bagus Sila Dharma I Gusti Bagus Sila Dharma I Kadek Dedy Antara Putra I Ketut Suta Negara I Made Ekayana I Nengah Jaya Nugraha I Nyoman Januarta Triska Putra I Putu Trisna Buana Putra I Wayan Arthana I Wayan Eka Dharmawan I Wayan Krisna Eka Putra I Wayan Krisna Eka Putra I Wayan Matsya Deva Nagendra I Wayan Matsya Deva Nagendra I Wayan Nuarsa IDA AYU ASTARINI IPG Eka Handrayana Putra Irwan Jatmiko Jero Ketut Tri Ayu Lestari Kadek Bagus Padmaningrat Kadek Dwi Artama Kadek Setiya Wati Kholifatul Aziz Kuncoro Teguh Setiawan Kuncoro Teguh Setiawan Luh Made Chandra Luh Made Chandra Luh Putu Ayu Depi Nurcahyani Made Narayana Adibhusana Made Ryan Dwiputra Made Suartana Naila Makfiya Ni Kadek Martini Ni Luh Kade Paramita Kusuma Ni Luh Putu Ayu Sumarni Ni Luh Putu Ratih Pravitha Ni Luh Putu Ria Puspitha Ni Putu Eva Damayanti Nidzar Muhammad Rafly Nikmah Fitria Nuraini Nuryani Widagti Pande Ketut Cahya Krisnanta Arioka Putra Bagus Panji Pamungkas Putra, I Nyoman Giri Putu Bagus Angga Utama Putu Eka Tulistiawan Rony Clinton Sabil Al Alif Syifa’ul Qolbiyatun Nisa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Tulistiawan, Putu Eka Valenthio Sidauruk Wati, Kadek Setiya Widiastuti Karim Widiastuti Karim Widiastuti Widiastuti Widiastuti Widiastuti Yasa, Putu Kumara YASUHIRO SUGIMORI Yasuhiro Sugimori Yoga Ibnu Graha Yulianto Suteja

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