Padrões e processos que estruturam (meta)comunidades de bacterioplâncton, da escala local à intercontinental

Abstract

Bacteria are key organisms for ecosystem functioning, being essential in biogeochemical cycles and closely related to other living organisms. Although these organisms have been studied for decades, their dynamics of space-time structuring could be better understood after the advent of culture-independent molecular approaches. These new techniques have revealed that not all bacteria are ubiquitous and the existence of biogeographic patterns of microorganisms. In addition, the integrated study between this group and macroorganisms can boost discoveries in the field of ecology and, on the other hand, the application of already established mathematical models provides new insights into the macroecological structure of these microorganisms. This thesis was divided into two parts. In part I I bring a theoretical introduction about the development of the discipline in the last decade and a summary of the latest ecological and genomic findings regarding the taxonomic groups most commonly found in continental aquatic environments. In part II, I present the results of my research divided into three chapters. The first chapter of this part deals with the local processes that potentially impact bacteria's ability to remain consistently abundant over time, which may affect the range of spatial distribution in a metacommunity, as more abundant organisms are generally more abundant. those that are more likely to be present in all locations in a given region. In the second chapter, I analyze the most relevant dispersion patterns for bacteria in a spatial matrix of about 250 thousand km². Finally, in Chapter 3, I sought to understand the impact of scale-up on the deterministic and stochastic processes that structure a bacterioplankton metacommunity. This work contributes to the understanding of how microrganisms may be distributed over a landscape in inland waters and what factors potentially determine their distribution and abundance.