Sains Malaysiana 52(4)(2023): 1315-1332

http://doi.org/10.17576/jsm-2023-5204-21

Mapping Sea Grass Coverage of Tanjung Benoa Bali Using Medium Resolution Satellite Imagery Sentinel 2B

(Pemetaan Liputan Rumput Laut Tanjung Benoa Bali Menggunakan Imejan Satelit Resolusi Sederhana Sentinel 2B)

ZAINUL HIDAYAH^1,*, LUCAS DE OLIVEIRA VIEIRA², RAHMA SAFITRI¹, HERLAMBANG AULIA RACHMAN¹ & ABDUR RAHMAN AS-SYAKUR^3,4

¹Department of Marine Science and Fisheries, Faculty of Agriculture, Universitas Trunojoyo Madura, Raya Telang 02 Madura East Java, Indonesia

²Laboratory of Systematics and Ecology of Aquatic Organisms, Centre of Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, State of Maranhão, Brazil

³Department of Marine Science, Faculty of Marine and Fisheries, Universitas Udayana

Bukit Jimbaran Campus Bali, Indonesia

⁴Environmental Research Centre, Universitas Udayana, Denpasar Bali, Indonesia

Diserahkan: 21 Julai2022/Diterima: 27 Februari2023

Abstract

Seagrass beds are important components of a coastal ecosystem. This ecosystem serves as the primer producers of the water food chain, habitat for marine biota, produces organic carbon, and indirectly contributes to the economic well-being of coastal communities. However, the ecosystem is vulnerable to damage caused by natural factors and human activities. The objectives of this study were, firstly to identify the distribution of seagrass beds in Tanjung Benoa using Sentinel 2B satellite imagery and secondly to compare classification results from two different approaches namely pixel-based image classification and object-based image classification. Accuracy-test was carried out using field data reference of 195 sample points in the form of a 10 m X 10 m transect. The image pre-processing process was conducted with Bottom of Atmosphere (BoA) correction using the Dark Object Subtraction (DOS) method. Furthermore, the water column correction was performed using the Depth Invariant Index (DII) and the Lyzenga algorithm. The mapping results showed that the area of seagrass beds in the shallow waters of Tanjung Benoa reaches 242.99 ha. There were seven seagrass species in the study area, with an average cover of 75%. The accuracy of object-based image classification was higher than that of pixel-based classification with a difference up to 25% for six classes classification and 15% for two classes classification. Excellent results for classifying seagrasses based on cover density can be obtained when high-resolution satellite imagery and OBIA are combined with the SVM or Fuzzy Logic algorithm.

Keywords: Image classification; seagrass beds; Sentinel 2B; Tanjung Benoa; water column correction

ABSTRAK

Hamparan rumput laut adalah komponen penting dalam ekosistem pantai. Ekosistem ini berfungsi sebagai pengeluar primer rantai makanan air, habitat biota marin, menghasilkan karbon organik dan secara tidak langsung menyumbang kepada kesejahteraan ekonomi komuniti pesisir. Walau bagaimanapun, ekosistem terdedah kepada kerosakan yang disebabkan oleh faktor semula jadi dan aktiviti manusia. Objektif kajian ini adalah, pertama untuk mengenal pasti taburan hamparan rumput laut di Tanjung Benoa menggunakan imej satelit Sentinel 2B dan kedua untuk membandingkan hasil pengelasan daripada dua pendekatan berbeza, iaitu pengelasan imej berasaskan piksel dan pengelasan imej berasaskan objek. Ujian ketepatan dijalankan dengan menggunakan rujukan data lapangan daripada 195 titik sampel dalam bentuk transek 10 m × 10 m. Proses pra-pemprosesan imej dijalankan berdasarkan pembetulan Bottom of Atmosphere (BoA) dengan menggunakan kaedah Dark Object Subtraction (DOS). Tambahan pula, pembetulan lajur air turut dilakukan dengan menggunakan Indeks Invarian Kedalaman (DII) dan algoritma Lyzenga. Hasil pemetaan menunjukkan bahawa keluasan hamparan rumput laut di perairan cetek Tanjung Benoa mencapai 242.99 ha. Terdapat tujuh spesies rumput laut di kawasan kajian dengan purata penutupan 75%. Ketepatan pengelasan imej berasaskan objek adalah lebih tinggi berbanding pengelasan berasaskan piksel dengan perbezaan sehingga 25% untuk pengelasan enam kelas dan 15% untuk pengelasan dua kelas. Keputusan yang baik untuk mengelaskan rumput laut berdasarkan kepadatan penutup boleh diperoleh apabila imej satelit resolusi tinggi dan OBIA digabungkan dengan algoritma SVM atau Fuzzy Logic.

Kata kunci: Hamparan rumput laut; pembentulan kolum air; pengelasan imej; Tanjung Benoa; Sentinel 2B

RUJUKAN

Adebayo, H.O., Otun, W.O. & Daniel, I.S. 2019. Change detection in land use/landcover of Abeokuta metropolitan area, Nigeria using multi-temporal Landsat remote sensing. Indonesian Journal of Geography 51(2): 217-223.

Ambo-Rappe, R., La Nafie, Y.A., Marimba, A.A. & Unsworth, R.K.F. 2021. Seagrass habitat characteristics of seahorses in Selayar Island South Sulawesi Indonesia. AACL Bioflux 14(1): 337-348.

Ariza, A., Robredo Irizar, M. & Bayer, S. 2018. Empirical line model for the atmospheric correction of sentinel-2A MSI images in the Caribbean Islands. European Journal of Remote Sensing 51(1): 765-776.

Brown, M.I., Pearce, T., Leon, J., Sidle, R. & Wilson, R. 2018. Using remote sensing and traditional ecological knowledge (TEK) to understand mangrove change on the Maroochy River, Queensland, Australia. Applied Geography 94(1): 71-83.

Coffer, M.M., Schaeffer, B.A., Zimmerman, R.C., Hill, V., Li, J., Islam, K.A. & Whitman, P.J. 2020. Performance across WorldView-2 and rapid eye for reproducible seagrass mapping. Remote Sensing of Environment 250(2): 37-49.

Congedo, L. 2021. Semi-automatic classification plugin: A python tool for the download and processing of remote sensing images in QGIS. Journal of Open Source Software 6(64): 3172-3182.

Cullen-Unsworth, L.C., Jones, B.L., Seary, R., Newman, R. & Unsworth, R.K.F. 2018. Reasons for seagrass optimism: Local ecological knowledge confirms presence of dugongs running. Marine Pollution Bulletin 134(1): 118-122.

Dangulla, M., Munaf, L.A. & Mohammad, F.R. 2020. Spatio-temporal analysis of land use/land cover dynamic in Sokoto metropolis using multi-temporal satellite data and land change modeller. Indonesian Journal of Geography 52(3): 306-316.

Dattola, L., Rende, F.S., Lanera, P., Di Mento, R., Dominici, R., Cappa, P., Scalise, S., Aramini, G. & Oranges, T. 2018. Comparison of Sentinel-2 and Landsat-8 OLI satellite images vs. high spatial resolution images (MIVIS and WorldView-2) for mapping Posidonia oceanica meadows. Remote Sensing 42(2). https://doi.org/10.1117/12.2326798. SPIE

Davies, T.W., Duffy, J.P., Bennie, J. & Gaston, K.J. 2014. The nature, extent, and ecological implications of marine light pollution. Frontiers in Ecology and the Environment 12(6): 347-355.

de Keukelaere, L., Sterckx, S., Adriaensen, S., Knaeps, E., Reusen, I., Giardino, C., Bresciani, M., Hunter, P., Neil, C., van der Zande, D. & Vaiciute, D. 2018. Atmospheric correction of Landsat-8/OLI and Sentinel-2/MSI data using iCOR algorithm: Validation for coastal and inland waters. European Journal of Remote Sensing 51(1): 525-542.

Dewi, A.N. & Abidin, Z. 2021. Analysis of the relationship of service quality, motivation and destination image to destination loyalty: a case study of Wonorejo mangrove ecotourism in Surabaya, East Java. Journal of Aquaculture and Fish Health 10(1): 46-55.

Fauzan, M.A., Wicaksono, P. & Hartono. 2021. Characterizing Derawan seagrass cover change with time-series Sentinel-2 images. Regional Studies in Marine Science 48(3): 1020-1048.

Fitrian, T., Kusnadi, A. & Persilette, R.N. 2017. Seagrass community structure of Tayando-Tam Island, southeast Moluccas, Indonesia. Biodiversitas 18(2): 788-794.

Fortes, M.D., Ooi, J.L.S., Tan, Y.M., Prathep, A., Bujang, J.S. & Yaakub, S.M. 2018. Seagrass in Southeast Asia: A review of status and knowledge gaps, and a road map for conservation. Botanica Marina 61(3): 269-288.

Gani, A., Nurjirana, Bakri, A.A., Adriany, D.T., Wuniarto, E., Khartiono, L.D., Satria, D.H., Hasan, V., Herjayanto, M., Burhanuddin, A.I., Moore, A.M. & Kobayashi, H. 2021. First record of Stiphodon annieae Keith & Hadiaty, 2015 (Teleostei, Oxudercidae) from Sulawesi Island, Indonesia. Check List 17(1): 261-267.

Gapper, J.J., El-Askary, H., Linstead, E. & Piechota, T. 2018. Evaluation of spatial generalization characteristics of a robust classifier as applied to coral reef habitats in remote islands of the Pacific Ocean. Remote Sensing 10(11): 105-125. 

Ha, N.T., Manley-Harris, M., Pham, T.D. & Hawes, I. 2020. A comparative assessment of ensemble-based machine learning and maximum likelihood methods for mapping seagrass using sentinel-2 imagery in Tauranga Harbor, New Zealand. Remote Sensing 12(3): 1-16.

Hasan, V. & Widodo, M.S. 2020. The presence of Bull shark Carcharhinus leucas (Elasmobranchii: Carcharhinidae) in the fresh waters of Sumatra, Indonesia. Biodiversitas 21(9): 4433-4439.

Hasan, V. & Islam, I. 2021. First inland record of Bull shark Carcharhinus leucas (Müller & Henle, 1839) (Carcharhiniformes: Carcharhinidae) in Celebes, Indonesia. Ecologica Montenegrina 38: 12-17.

Hasan, V., Gausmann, P., Nafisyah, A.L., Isroni, W., Widodo, M.S., Islam, I. & Chaidir, R.R.A. 2021. First record of Longnose marbled whipray Fluvitrygon oxyrhyncha (Sauvage, 1878) (Myliobatiformes: Dasyatidae) in Malaysian waters. Ecologica Montenegrina 40: 75-79.

Hidayah, Z. & Wiyanto, D.B. 2017. Combining satellite image analysis and in-situ measurement to determine the condition of coral reef ecosystem of Mandangin Island, East Java, Indonesia. Asian Journal of Microbiology, Biotechnology and Environmental Sciences 19(3): 1-8.

Hidayah, Z., Rachman, H.A. & As-Syakur, A.R. 2022. Mapping of mangrove forest and carbon stock estimation of east coast Surabaya, Indonesia. Biodiversitas 23(9): 4826-4837.

Hossain, M.D. & Chen, D. 2019. Segmentation for Object-Based Image Analysis (OBIA): A review of algorithms and challenges from remote sensing perspective. ISPRS Journal of Photogrammetry and Remote Sensing 150(1): 115-134.

Islamy, R.A. & Hasan, V. 2020. Checklist of mangrove snails (Mollusca: Gastropoda) in south coast of Pamekasan, Madura Island, East Java, Indonesia. Biodiversitas 21: 3127-3134.

Kawaroe, M., Nugraha, A.H., Juraij & Tasabaramo, I.A. 2016. Seagrass biodiversity at three marine ecoregions of Indonesia: Sunda Shelf, Sulawesi Sea and Banda Sea. Biodiversitas 17(2): 585-591.

Kohlus, J., Stelzer, K., Müller, G. & Smollich, S. 2020. Mapping seagrass (Zostera) by remote sensing in the Schleswig-Holstein Wadden Sea. Estuarine, Coastal and Shelf Science 238: 106699.

Kovacs, E., Roelfsema, C., Lyons, M., Zhao, S. & Phinn, S. 2018. Seagrass habitat mapping: How do landsat 8 OLI, Sentinel-2, ZY-3A and Worldview-3 perform? Remote Sensing Letters 9(7): 686-695.

Lizcano-Sandoval, L., Anastasiou, C., Montes, E., Raulerson, G., Sherwood, E. & Muller-Karger, F.E. 2022. Seagrass distribution, areal cover, and changes (1990-2021) in coastal waters off west-central Florida, USA. Estuarine Coastal and Shelf Science 279(1): 108-134.

León-Pérez, M.C., Hernández, W.J. & Armstrong, R.A. 2019. Characterization and distribution of seagrass habitats in a Caribbean Nature Reserve using high-resolution satellite imagery and field sampling. Journal of Coastal Research 35(5): 937-947.

Manik, H.M. & Apdillah, D. 2020. Remote sensing of seagrass and seabed using acoustic technology in Bintan Seawater, Indonesia. Pertanika Journal of Science and Technology 28(2): 421-439.

Mckenzie, L.J., Nordlund, L.M., Jones, B.L., Cullen-unsworth, L.C., Roelfsema, C. & Unsworth, R.K.F. 2020. The global distribution of seagrass meadows information for data reuse ecosystems. Environmental Research Letters 15(7): 158-170.

Medina, J.A.V. & Atehortua, B.E.A. 2018. Comparison of maximum likelihood, support vector machines and random forest techniques in satellite image classification. Tecnura 23(59): 13-26.

Mogstad, A.A., Johnsen, G. & Ludvigsen, M. 2019. Shallow-water habitat mapping using underwater hyperspectral imaging from an unmanned surface vehicle: A pilot study. Remote Sensing 11(6): 685-699.

Niroumand-Jadidi, M., Pahlevan, N. & Vitti, A. 2019. Mapping substrate types and compositions in shallow streams. Remote Sensing 11(3): 262.

Nugraha, A.H., Tasabaramo, I.A., Hernawan, U.E., Rahmawati, S., Putra, R.D. & Darus, R.F. 2021. Diversity, coverage, distribution and ecosystem services of seagrass in three small islands of northern Papua, Indonesia: Liki Island, Meossu Island and Befondi Island. Biodiversitas 22(12): 5544-5549.

Nurjirana, Burhanuddin, A.I., Keith, P., Haris, A., Moore, A.M., Afrisal, M., Gani, A., Hasan, V., Wuniarto, E., Bakri, A.A. & Adriany, D.T. 2022. Additional records of Sicyopus discordipinnis (Watson, 1995) (Oxudercidae: Sicydiinae) in Central Sulawesi, Indonesia. Cybium 46(1): 041-043.

Pardamean, A.L., Islamy, R.A., Hasan, V., Herawati, E.Y. & Mutmainnah, N. 2021. Identification and physiological characteristics of potential indigenous bacteria as bioremediation agent in the wastewater of sugar factory. Sains Malaysiana 50(2): 279-286.

Poursanidis, D., Traganos, D., Teixeira, L., Shapiro, A. & Muaves, L. 2021. Cloud-native seascape mapping of Mozambique's Quirimbas National Park with Sentinel-2. Remote Sensing in Ecology and Conservation 7(2): 275-291.

Poursanidis, D., Traganos, D., Reinartz, P. & Chrysoulakis, N. 2019. On the use of Sentinel-2 for coastal habitat mapping and satellite-derived bathymetry estimation using downscaled coastal aerosol band. International Journal of Applied Earth Observation and Geoinformation 80(1): 58-70.

Prarikeslan, W., Hermon, D., Suasti, Y. & Putra, A. 2019. Density, coverage and biomass of seagrass ecosystem in the Lobam Island, Bintan Regency - Indonesia. IOP Conference Series: Earth and Environmental Science 314: 012024.

Rahman, A. 2013. Benthic habitat mapping from seabed images using ensemble of color, texture, and edge features. International Journal of Computational Intelligence Systems 6(6): 1072-1081.

Rahman, F.A., Qayim, I. & Wardiatno, Y. 2018. Carbon storage variability in seagrass meadows of Marine Poton Bako, East Lombok, West Nusa Tenggara, Indonesia. Biodiversitas 19(5): 1626-1631.

Richards, J.A. & Jia, X. 2006. Remote Sensing Digital Image Analysis: An Introduction. Springer. https://doi.org/10.1007/3-540-29711-1

Sabilah, A.A., Siregar, V.P.S. & Amran, M.A. 2021. Comparison of seagrass cover classification based-on SVM and Fuzzy algorithms using multiscale imagery in Kodingareng Lompo Island. Jurnal Ilmu dan Teknologi Kelautan Tropis 13(2): 97-112.

Saraswati, S.A., Toruan, L.N.L., Suteja, Y., Karmen, D. & Wijaya, P.E.P. 2021. Rob potential in the coastal city of  Kupang, East Nusa Tenggara (NTT). Journal of Aquaculture and Fish Health 10(3): 304-311.

Short, F., Carruthers, T., Dennison, W. & Waycott, M. 2007. Global seagrass distribution and diversity: A bioregional model. Journal of Experimental Marine Biology and Ecology 350(2): 3-20.

Siregar, V.P., Agus, S.B., Subarno, T. & Prabowo, N.W. 2018. Mapping shallow waters habitats using OBIA by applying several approaches of depth invariant index in North Kepulauan Seribu. IOP Conference Series: Earth and Environmental Science 149: 012052. https://doi.org/10.1088/1755-1315/149/1/012052.

Sjafrie, N.D.M., Hernawan, U.E., Prayudha, B., Rahmat, Supriyadi, I.H., Iswari, M.Y., Suyarso, Anggraini, K. & Rahmawati, S. 2018. Status Padang Lamun. Pusat Penelitian Oseanografi-LIPI. 53(9).

Supriyadi, I.H., Iswari, M.Y. & Suyarso. 2018. Kajian awal kondisi padang lamun di perairan timur Indonesia. Jurnal Segara 14(3): 169-177.

Thalib, M.S., Nurdin, N. & Aris, A. 2018. The ability of Lyzenga's algorithm for seagrass mapping using Sentinel-2A imagery on small island Spermonde Archipelago, Indonesia. IOP Conference Series: Earth and Environmental Science 165: 012028. https://doi.org/10.1088/1755-1315/165/1/012028

Traganos, D., Aggarwal, B., Poursanidis, D., Topouzelis, K., Chrysoulakis, N. & Reinartz, P. 2018. Towards global-scale seagrass mapping and monitoring using Sentinel-2 on Google Earth Engine: The case study of the Aegean and Ionian Seas. Remote Sensing 10(8): 1-14.

Tzotsos, A. 2006. A support vector machine approach for object based image. Proceedings of 1st International Conference on Object-Based Image Analysis, Negnevitsky. pp. 4-15.

Unsworth, R.K.F., Nordlund, L.M. & Cullen-Unsworth, L.C. 2019. Seagrass meadows support global fisheries production. Conservation Letters 12(1): 1-8.

Unsworth, R., Ambo-Rappe, R., Jones, B., Nafie, Y., Irawan, A., Hernawan, U.E., Moore, A.M. & Unsworth, L.C. 2018. Indonesia's globally significant seagrass meadows are under widespread threat. Science of the Total Environment 634(1): 279-286.

William-Schaduw, J.N. & Ivone Kondoy, K.F. 2020. Seagrass percent cover in small islands of Bunaken National Park, North Sulawesi Province, Indonesia. AACL Bioflux 13(2): 951-957.

^*Pengarang untuk surat-menyurat; email: zainulhidayah@trunojoyo.ac.id