Resumo Objetivo A urbanização leva a mudanças rápidas na estrutura e função do ecossistema. Terras úmidas em câmpus universitários sujeitos ao desenvolvimento da urbanização podem ser usados como estudos de caso de pesquisa aquática multidisciplinar e boas práticas ambientais que promovam a sustentabilidade. Métodos Foi realizado um estudo paleolimnológico em um lago semiartificial em um campus universitário no sul do Brasil para inferir impactos históricos e mudanças ecológicas desde a década de 1970 por meio de abordagens complementares: dados históricos, nutrientes, isótopos estáveis δ13C e δ15N, diatomáceas, microplásticos e análise da comunidade microbiana associada. Resultados O processo de eutrofização começou a se intensificar após o uso noturno por aves aquáticas de árvores como poleiros, e especialmente após o estabelecimento de construções ao longo das margens com fossa séptica de esgoto sanitário, que ocasionalmente transbordava e carreava material para o lago. Ao longo de décadas, identificamos um processo limnológico de hipertrofização que induziu a florações recorrentes de cianobactérias e proliferação maciça de macrófitas, juntamente com mudanças isotópicas e ocupação de algas com várias transições entre estados alternativos de lagos rasos. Tal processo limnológico foi claramente espelhado nas tendências de eutrofização paleolimnológica e mudanças isotópicas da matéria orgânica sedimentar. A deposição de microplásticos foi detectada como proxy para a intensificação da urbanização especialmente durante a construção das instalações da Universidade. Conclusões O uso combinado de dados paleolimnológicos e limnológicos históricos representa uma abordagem poderosa para identificar os impactos naturais e culturais no lago e identificar estratégias de manejo baseadas em tais informações científicas.

Abstract Aim Urbanization leads to rapid changes in ecosystem structure and function. Wetlands on university campuses under urbanization pressure could be used as case studies of multidisciplinary aquatic research and good environmental practices promoting sustainability. Methods A paleolimnological study was undertaken in a semi-artificial lake on a university campus in southern Brazil to trace historical impacts and ecological changes back to the mid-1970s through complementary approaches: historical data, nutrients, δ13C and δ15N stable isotopes, diatoms, microplastics and associated microbial community analysis. Results The eutrophication process started to intensify after the lake was used for nocturnal roosting by waterbirds, and especially after the establishment of constructions along the margins with septic tank sanitary sewage, which eventually spilled and leached into the lake. Over decades, we identified a limnological hypertrophication process leading to recurrent cyanobacterial blooms and massive macrophyte proliferation coupled with changes in isotopic ratios and algal occupation with several transitions between shallow lake alternative states. Such a limnological process has resembled the paleolimnological eutrophication trends and isotopic changes in sedimentary organic matter. The microplastic deposition was detected as a proxy for the intensification of urbanization, especially during the construction of the University facilities. Conclusions The combined use of paleolimnological and historical limnological data represents a powerful approach for inferring both natural and cultural impacts on the lake, and identifying management strategies based on such scientific information.

ABSTRACT Many questions about the role of planktonic organisms remain unanswered because of the difficulty in obtaining a medium where bacteria and fungi are not present. Moreover, an excess load of these microorganisms in phytoplankton cultures and zooplankton organisms may cause nutrient competition or diseases and consequently the death of the organisms of interest. For this reason, we reviewed several methods that have been used to obtain axenic planktonic cultures through specific metabolic inhibitors, such as antibiotics and antifungal agents. From 1940 to 2016, most research was related to microalgae and crustacean's cultures, with the antimicrobials: penicillin, streptomycin, chloramphenicol, oxytetracycline, neomycin and nystatin being the most frequently used. The studies that applied antimicrobials agents to planktonic cultures were mainly focused on being able to culture them and to answer questions about the role of bacteria in aquatic communities without previous testing their effectiveness or their effects on non-target organisms. Therefore, this review sought to determine the correct use of antimicrobials in cultures of planktonic organisms to prevent bacterial and fungal growth, without causing damage to non-target organisms and may assist in the implementation of ecologically-oriented scientific experiments where bacterial and/or fungal inhibition is necessary.