Microplásticos em ambientes marinhos e estuarinos: revisão bibliográfica, distribuição (Baía de Ilha Grande - RJ), composição do biofilme (Baía de Guanabara - RJ) e alterações na velocidade de afundamento

Abstract

Plastic particles smaller than 5 mm are classified as microplastics (MP), and represent the numerically most abundant category in marine environments due to the constant fragmentation of particles after being released into the environment. Once released into water bodies, synthetic polymers are quickly colonized by biofilm-forming microorganisms that secrete extracellular polymeric substances on the surface of the plastic, enabling the aggregation of particles and other microorganisms. The formation of biofilms can lead to increased palatability, as well as interfere with the density and consequently the buoyancy of MP. The microbial communities that colonize MP differ from the communities of microorganisms that form biofilms on natural substrates, as well as differ from microorganisms that do not form biofilms and are suspended or buried in the marine environment, suggesting that the presence of MP in marine environments may favor the development of exotic microbial community to the detriment of native ones, negatively affecting ecological functions and altering biogeochemical processes, in addition to the ability to carry pathogenic organisms. This work is divided into three chapters. Chapter 1 consists of a literature review, whose objective is to identify the main gaps in research related to MP in marine and estuarine environments, and to indicate possible directions to expand both global and regional knowledge about the formation of biofilms in MP and the composition of the microbial communities associated with these particles. Chapter 2 covers a descriptive study on the quantitative and qualitative distribution of MP in Ilha Grande Bay, aiming to assess MP pollution in this region, which has been little investigated so far. Chapter 3 is an experimental approach with the purpose of describing the communities of microorganisms associated with microparticles of different polymers incubated in Guanabara Bay, as well as examining the changes caused by the presence of biofilms in the hydrodynamic behavior of PM, with a view to its future application. in hydrodynamic models for Ilha Grande Bay and Guanabara Bay.