Testate amoebae (TA) are unicellular protozoans enclosed in a test capable of indicating a wide variety of environmental conditions. Among others, characteristics such as short life cycle, great sensitivity and worldwide distribution makes them adequate bioindicators. As a complement to physical and chemical measurements, biomonitoring can be a cheaper and fastest way of environmental monitoring. This research sought to evaluate the extent of TA use in biomonitoring and the responses given by them to environmental features. The research was conducted in Scielo, Science Direct, Online Library, Google Scholar and Capes Journal Portal and yielded 211 papers. TA bioindication is able to provide information on metal, trace element and atmospheric pollution, and to point out different trophic states, pH, and evidence on characteristics of hydrology. Further, TA can be used in paleoenvironmental reconstruction as they reflect climate, volcanic and even sea level change phenomena. Sometimes, together with other organisms in environmental analysis, they have shown to be an important complement to biomonitoring. Additionally, a functional traits approach has been recently included as a promising tool. Methodological adjustments that have been conducted throughout the years are allowing TA use to be more reliable and precise. This review provides insight on the many possible functions of TA in bioindication studies, highlighting their wide use as bioindicators.

The aim of this study was to elaborate a taxonomic survey on the testate amoebae of the Family Arcellidae in coastal streams in the State of Rio de Janeiro. Six samplings were conducted in Ubatiba coastal stream (Maricá, RJ). In total, 130 liters water were filtered through a conical net of 60-μm mesh and preserved in 4% formalin. Organisms were identified with the aid of an inverted trinocular microscope. The morphological characteristics (lobose testate amoebae with shell composed of granular chitinoid elements) of each species were recorded. The species were described and illustrated. For the verification of new taxa records of Arcellidae in Rio de Janeiro and their distribution in Brazil, a search based on index articles by Scopus, Web of Science and Google Scholar using the keywords "tecamebas", "testate amoebae", "Arcella", "Arcellidae", "Brazil" and "Rio de Janeiro", was performed. Eight Arcellidae species were recorded. Some ecological and taxonomic information was provided. Due to the small amount of information on testate amoebae, this study is important because it reduces the knowledge gap regarding this community in the State of Rio de Janeiro. Furthermore, we suggest new studies on species identification to be conducted to expand regional knowledge about these organisms.

Aim The free-living protists testate amoebae are recognized as being bioindicators, able to reveal environmental alteration via remodifying richness, diversity and abundance of species. To assess the scientific production on the use of testate amoebae as bioindicators, a scientometric analysis was undertaken from 1960 to 2020. Methods The sourcing of scientific articles derived from Google Academic, Scielo, Science Direct and Online Library research platforms. All selected papers were factored according to chronology, journal of publication, country, authors’ affiliation, whether the study was empirical or experimentation, if it included solely testate amoebae or other groups of organisms, and aspects of the environment. Results A total of 215 papers from ninety-two journals revealed a notable increase in publication numbers over the last decades. The two journals that most published data on this theme were Microbial Ecology and Ecological Indicators. Whilst the largest number of papers was published in the European Continent, the countries that most contributed to the subject were Canada in the temperate region and Brazil in the tropics. Edward A.D. Mitchell published the largest number of studies and regarding institutions the Franche-Comté University. The majority of papers that associated testaceans as bioindicators were empirical, conducted with Thecamoebian inhabiting moss and as such, dissociated from other groups. Conclusions Despite a suggested uptick in research of testaceans as bioindicators, our results indicate a concentration of studies to limited regions of the globe. In another aspect, a great number of studies assess testaceans’ community as-a-whole, showing a shortage of in-depth knowledge into species and functional groups. Therefore, our survey points to a wide variety of aquatic ecosystems devoid of study matter, indicating the need to foster the research on testate amoeba's role as bioindicators especially in the tropical regions.

As bromélias, devido às suas características morfológicas, são capazes de fornecer microhabitats para diversas formas de vida, dentre elas destacam-se os organismos zooplanctônicos. Desse modo, este estudo teve como objetivo descrever a comunidade zooplanctônica presente em bromélias de uma região natural de mata atlântica. Variáveis limnológicas foram mensuradas in situ e as amostras de zooplâncton coletadas utilizando ferramentas específicas, sendo posteriormente analisadas em microscópio óptico. Os táxons mais representativos encontrados foram os protistas dos grupos Cryptophyta e Ciliophora. A maior riqueza encontrada foi de rotíferos, provavelmente relacionada aos altos valores de abundância de ciliados e flagelados, que os servem de alimento. Também foi possível observar as interações faunísticas que existem nesse habitat, obtendo como exemplo o mecanismo de hiperforesia. Por fim, graças à variedade de táxons zooplanctônicos encontrados, desmistifica-se a ideia de que esse ambiente se comporta apenas como um criadouro de vetores de doenças.