Trends and gaps in microplastics research in Tropical freshwater ecosystems.

Although the contamination of microplastics is a very recent topic, knowledge increased rapidly, especially in the last decade. Despite this, freshwater ecosystems have received less attention than marine ones, particularly in the tropics. Considering the particularities of Tropical freshwater ecosystems that can be important in the microplastics dynamic, such as the high rate of untreated water, the flooding dynamics and high number of reservoirs, our review aims to present the state of the research of microplastic contamination in Tropical freshwater ecosystems, emphasizing the knowledge advances and existing gaps. We compared studies in different countries, ecosystems and type of samples, and identified gaps and needs for futures research. Although research and the complexity of studies have increased over the years, Tropical freshwater ecosystems are still understudied. We emphasized the need for more studies in African countries and Tropical Australia, as well as in reservoirs across all Tropical regions. It is also crucial to evaluate contamination related to flooding dynamics and in aquatic invertebrates. Advancements in research on this topic are essential to provide a clear picture of the real problem in the tropics, leading to the possibility of better mitigation and conservation actions in the future.