Seasonal variation of marine debris at Manado Bay (North Sulawesi, Indonesia)

Abstract

Marine debris has become a global concern due to its impact on marine ecosystems. These materials generally come from land and are deposited to marine environment through different agent of carrier. Many efforts are being made to monitor the dynamics of the debris including their presence and their variability in relation to seasons. The latter are assumed from the facts that the presence of the debris is mainly affected by the waves, speed, and direction of ocean currents in the area of interest. In this study, variation of debris in dry and wet season at Manado Bay was assessed by using a shoreline technique. Two locations are selected, Bailang and Malalayang beach. The samplings were conducted in August 2019 (represent dry season) and January 2020 (represent wet season). Several parameters are examined during the sampling; they are: amount of material, type of debris, composition, and spatial density of each type for macro-size (>2.5 cm) and meso-size (0.5–2.5 cm). The results showed that there was variation on composition and density, but the types of debris remain unchanged. Our present study concluded that variation in the season do not affect the variability of marine debris in Manado Bay.