This study investigated the use of an exotic fish species Oreochromis niloticus as a bio-indicator organism in active biomonitoring of Yellow Jacket and Mazowe rivers, Zimbabwe, receiving acid mine drainage from Iron Duke Mine. The Yellow Jacket River flows through Iron Duke Pyrite Mine while the Mazowe River passes through the Mazowe factory and estate shop that receives runoff from intensive agricultural activities. Active biomonitoring (ABM) exposures were conducted for 6 weeks in effluent-contaminated sections of the rivers during high flow, from February to March 2013. A set of biomarkers of exposure and effect (glutathione S-transferase, catalase and metallothioneins) were selected and their responses determined in O. niloticus liver, gills and muscle. We hypothesized that the increase in activities of GST, CAT and MT in exposed fish, in comparison to control fish, can be used to assess river water quality using O. niloticus. Biomarker expression was measured after 4 and 6 weeks and compared against control fish kept under laboratory conditions without contaminants. Concentrations of zinc, cadmium, chromium, nickel, lead, copper, manganese, arsenic and iron were measured in flowing water, riverbed sediments and muscle tissue of actively biomonitored O. niloticus. Key water quality parameters, including dissolved oxygen and conductivity, clearly showed a pollution gradient from Iron Duke Mine. Expression of CAT and GST was highest in the liver, compared to gills and muscles, after 4 and 6 weeks of exposure, and their expression was lower (p < 0.05) in control fish. The expression of the enzymes was not significantly different after 6 weeks compared to 4 weeks. Increased enzyme expressions at Site 1, which is upstream from Iron Duke Mine, were comparable to enzyme expressions at Sites 3, 4, 5 and 6, which correlated with increased zinc concentrations in the exposed fish muscle tissue. The general order of metal concentrations was sediments > water > fish, except for zinc, which had the highest bioconcentration factors. Using the GST, CAT and MT we concluded that Mazowe and Yellow Jacket rivers are contaminated and that these oxidative stress biomarkers can successfully be used in assessing pollution from point sources such as acid mine drainage, as well as diffuse sources of pollutants such as commercial agriculture.

Drosophila Fallen, 1823 (Diptera, Drosophilidae) é, há muito tempo, um organismo modelo em pesquisas de genética e evolução. A ecologia destas moscas, no entanto, apenas recentemente foi melhor estudada. Trabalhos recentes apontam que as assembléias de Drosophila podem ser utilizadas como bioindicadoras de degradação de ambientes florestais. Neste trabalho, foi avaliado o potencial bioindicador dos drosofilídeos em um ambiente de restinga, naturalmente aberto. Dados de nove coletas sazonais consecutivas revelaram um forte padrão de flutuação temporal na maioria dos grupos de espécies de Drosophila. O grupo D. willistoni foi mais abundante nos outonos, enquanto os grupos D. cardini e D. tripunctata foram, respectivamente, expressivos nos invernos e primaveras, e o grupo D. repleta em ambas as estações. As espécies exóticas D. simulans Sturtevant, 1919 (do grupo D. melanogaster) e Zaprionus indianus Gupta, 1970 foram mais abundantes nos verões. Em geral, a estrutura desta assembléia não mostrou as mesmas características de ambientes florestais ou urbanos, mas mostrou-se similar às florestas nos invernos e aos urbanizados nos verões. Isto demonstra que esta localidade já pode estar sofrendo impacto da urbanização. Também, este pode ser interpretado como um local facilmente invadido por espécies exóticas, o que pode levar à homogeneização biótica e, portanto, pode por em cheque o uso de assembléias de drosofilídeos como bioindicadores em ambientes abertos.

Drosophila Fallen, 1823 (Diptera, Drosophilidae) is for long a well-established model organism for genetics and evolutionary research. The ecology of these flies, however, has only recently been better studied. Recent papers show that Drosophila assemblies can be used as bioindicators of forested environment degradation. In this work the bioindicator potential of drosophilids was evaluated in a naturally opened environment, a coastal strand-forest (restinga). Data from nine consecutive seasonal collections revealed strong temporal fluctuation pattern of the majority of Drosophila species groups. Drosophila willistoni group was more abundant at autumns, whereas D. cardini and D. tripunctata groups were, respectively, expressive at winters and springs, and D. repleta group at both seasons. The exotic species D. simulans Sturtevant, 1919 (from D. melanogaster group) and Zaprionus indianus Gupta, 1970 were most abundant at summers. Overall, the assemblage structure did not show the same characteristics of forested or urban environments, but was similar to the forests at winters and to cities at summers. This raises the question that this locality may already been under urbanization impact. Also, this can be interpreted as an easily invaded site for exotic species, what might lead to biotic homogenization and therefore can put in check the usage of drosophilid assemblages as bioindicators at open environments.

A distribuição e abundância do coral azooxantelado Tubastraea Lesson, 1829 foram estimadas em diferentes profundidades e inferido seu ângulo preferencial de ocorrência em costões rochosos da Ilha Grande, Brasil. Tubastraea é um escleractínio ahermatípico introduzido no Brasil que, provavelmente, chegou incrustado em casco de navios e/ou plataformas de petróleo na década de 80. O coral exótico foi encontrado em uma extensão geográfica de 25 km no Canal Central da Ilha Grande. A abundância de Tubastraea foi quantificada em relação à profundidade usando três diferentes métodos: densidade de colônias e porcentagem de cobertura por estimativa visual e pontos de intersecção. O coral Tubastraea demonstrou ter ampla tolerância à temperatura e dessecação, sendo encontrado em águas muito rasas (0,1-0,5 m), apesar de haver substrato consolidado disponível em maiores profundidades em todas as estações amostradas. Em todas as estações 1-5 colônias foram mais freqüentemente encontradas em cada 0,25 m², porém, ocasionalmente, mais que 50 colônias por 0,25 m² foram encontradas, indicando um padrão de agregação na distribuição espacial deste coral. Tubastraea foi encontrado ocupando todos os possíveis ângulos de inclinação no Canal Central da Ilha Grande, porém, a maior parte das colônias foram encontradas ocupando ângulos entre 80-100°. Desta forma, a amplitude de inclinação de substrato e profundidades viáveis ao recrutamento do coral indicam que este organismo, de grande tolerância ecológica, tem a potencialidade de colonizar novas áreas e aumentar sua distribuição no Brasil.

The distribution and abundance of azooxanthellate coral Tubastraea Lesson, 1829 were examined at different depths and their slope preference was measured on rocky shores on Ilha Grande, Brazil. Tubastraea is an ahermatypic scleractinian nonindigenous to Brazil, which probably arrived on a ship's hull or oil platform in the late 1980's. The exotic coral was found along a great geographic range of the Canal Central of Ilha Grande, extending over a distance of 25 km. The abundance of Tubastraea was quantified by depth, using three different sampling methods: colony density, visual estimation and intercept points (100) for percentage of cover. Tubastraea showed ample tolerance to temperature and desiccation since it was found more abundantly in very shallow waters (0.1-0.5 m), despite the fact that hard substratum is available at greater depths at all the stations sampled. At most sites, 1 to 5 colonies per 0.25 m² were found most frequently, but occasionally more than 50 colonies were found per 0.25 m², indicating a somewhat gregarious spatial distribution for this coral. The coral Tubastraea was found to occupy slopes of every possible angle in the Canal Central of Ilha Grande, but more colonies were found occupying slopes of 80 to 100°. Therefore, its insensitivity to angles of recruitment and its tolerance for different depths makes it an organism with great ecological tolerance, with a potential to colonize new areas and increase its current range in Brazil's coastal waters.