SPATIAL-TEMPORAL VARIATION OF MARINE DEBRIS ALONG THE COASTAL AND ESTUARY IN MANADO BAY AND ITS ENVIRONS DURING 2021-2022

• Main Author: Novianti Andakke, Jeszy
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68111
• Institution: Institut Teknologi Bandung

Nowadays, Indonesia is facing a crisis of marine debris pollution which continues to increase yearly. The existence of marine debris is a new threat that has a terrible impact on the marine ecosystem and the socio-economic sustainability of the community. Garbage can enter the sea through rivers, city drainage, maritime activities, and tourists. Currents, tides, and waves cause the movement of marine debris from one place to another. Based on this, the Government of Indonesia has issued a regulation in Presidential Regulation no. 83 of 2018 concerning the Handling of Marine Debris. Many studies related to marine debris have been carried out in coastal areas of Indonesia, one of which is the coast of Manado Bay and its surroundings. Research on marine debris on several beaches in Manado Bay has been carried out since 2019 and only focuses on low tide conditions and only two seasons. So conducted this research to complete the baseline data by adding locations at the mouth of the river, and garbage collection was also carried out during high tide conditions. First Inter-Monsoon dan second Inter-Monsoon was also carried out in this study to see variations in marine debris each season. Sampling was conducted by using the guidelines of marine debris quantification published by the Ministry of Environment and Forestry of the Republic of Indonesia (KLHK, 2020), The Ondara and Dhiauddin method (2021), and the Commonwealth Scientific and Industrial Research Organization survey method (2017). Based on the study's results, the dominant type of marine debris found at the beach and river estuaries is the type of plastic material, with a proportion of 57-81% and 78-81%, respectively. Each waste found is characterized by its size and shape. Overall, the size of macro waste found was greater than that of meso waste, with a total percentage of the macro waste size of 76% and meso waste of 24%. Its cause because the production of macro waste is more widely used in daily life and changing macro waste to a smaller size requires a long process. The whole form of waste was more commonly found in macro waste, with a total percentage is 68%. While the fragment form was found in meso waste with a total percentage is 91%. This is presumably because meso waste is part of the macro waste that has been fragmented into small pieces. Variations in the composition of marine debris were found at each location and showed the same variation in each season. It consists of 9 types of constituent materials, namely (PL) Plastic, (FP) Plastic Foam, (CL) Cloth, (PC) Paper and Cardboard, (ME) Metal, (RB) Rubber, (GC) Glass and Ceramics, (WD) Wood and (OT) Other Materials Seasonal differences only affect the density of waste. In this case, it is related to the current direction that can carry marine debris from one place to another. The results in the field show the same thing between the current direction and the location of the most pile in each season. Currents in Manado Bay in the Southwest Monsoon dominantly move north and northeast so that the accumulation of debris will be more in the Northern Bay area, namely Talawaan Bajo Beach, which is 192 pieces with a density of 7.68 items/m2. In the Northeast Monsoon, the current dominant movement to the east, which causes the highest debris density, is found at Bailang Beach with 21.16 items/m2 and Malalayang Beach with 3.48 items/m2. In the Second Inter-Monsoon, the pile area was shown as the same area as the west season, but there were differences in the amount found. This happens because of the difference in current velocity in these two seasons. In the First Inter-Monsoon, the influence of the current is seen on Tasik Ria Beach, where in this season, the current moves northeast towards Mandolang Beach, allowing for the transfer of waste. However, this waste transfer still needs to be studied further. Activities at each location will affect the amount of waste found. Talawaan Bajo Beach, Bailang Beach, and Sindulang Beach are the beaches with the highest density. These three locations have more crowded activities than the other four beaches. Locations that have more activity tend to be found with more piles of waste. This is because a large number of these activities causes the input sources of waste to be more diverse.