This chapter explores the dynamics of macrobenthos that are affected by the disposal of tailings in Buyat Bay, Minahasa, Indonesia. Disposal of tailings on the seabed (submarine disposal) in Buyat Bay is is influenced by dispersion in water, which impacts the marine environment and ecosystem. This marine ecosystem is affected by the ocean conditions. Ideally, the condition of the sea with tailings disposal and land filling is such that the deep sea and ocean dynamics are not negatively affected and that the tailings do not harm the marine ecosystems. This study aims to evaluate the dynamics of marine ecosystems after the disposal of tailings in Buyat Bay. Previous incidental and temporal studies have been performed. However, studies that holistically assess the impact of tailings disposal on marine ecosystems with long-term time series data covering a time span of 10 years after the disposal have not been performed. This study is important because the sustainability of marine ecosystems will ultimately affect human security. Sediment samples were analyzed in laboratories. This study shows the marine ecosystem dynamics based on the diversity of marine biota (macrobenthos) over 10 years and illustrates the stages of succession in the marine ecosystem following tailing disposal as well as indicates the linkage between the environment approaches microbenthos take to maintain their viability.