Rio Doce Research Articles

Taxonomic revision of the genus Australoheros RICAN & KULLANDER, 2006 (Teleostei: Cichlidae) with descriptions of nine new species from southeastern Brazil

Nine new species of Australoheros from Southern Brazil are herein described: Australoheros autrani from rio São João basin; A. barbosae from rio Preto basin, rio Paraíba do Sul basin; A. ipatinguensis from rio Doce basin; A. macacuensis from rio Macacu basin, A. macaensis from rio Macaé basin, A. muriae from rio Muriaé basin, rio Paraíba do Sul basin; A. paraibae from rio do Peixe basin, rio Paraíba do Sul basin; A. robustus from córrego da Areia basin, rio Paraíba do Sul basin; and A. saquarema from lagoa de Saquarema system. The new species are easily distinguished from their congeners from South Brazil, Northern Argentina and North Uruguay (except A. scitulus) by having 12 caudal vertebrae (vs. 13 or more). The new species are distinguished from A. scitulus and A. forquilha by having no dark marks on side of head (vs. dark marks present on side of head), and differ from A. ribeirae by meristic counts. The nine new species differ from each other by several meristic counts, some morphometric measurements, shape of the snout and color pattern. A new phylogeny of the genus is required, because when these new species from Southern Brazil are included into the groups proposed by RÍCAN & KULLANDER (2006, 2008), the characters turns incongruent.

The inverted trophic cascade in tropical plankton communities: impacts of exotic fish in the Middle Rio Doce lake district, Minas Gerais, Brazil

The present study deals with the ecological impacts of the introduction of two alien species of piscivorous fish in several lakes of the Middle Rio Doce lake district in Minas Gerais, Brazil. It was demonstrated that these effects were not restricted only to the fish community. The introduction of the predatory red piranha Pygocentrus nattereri and the tucunaré Cichla cf. ocellaris caused not only a sharp decrease in the number of native fish species, but also major shifts in other trophic levels. Just after the fish were introduced, most lakes began to show conspicuous changes in phytoplankton species composition, in which Cyanophyceae gradually came to dominate. The zooplankton community lost several species, and in some cases, such as Lake Carioca, all the cladoceran species disappeared. On the other hand, invertebrate predators, represented by the dipteran Chaoboridae, boomed in the lake, with higher densities of exotic species, probably as a result of the 'ecological release' by reduction of the original fish fauna. There was a general trend of species loss in different trophic levels. All these changes are apparently associated with decreases in water quality. The present situation in these lakes demands new approaches to the management and conservation of these ecosystems.

Arquidiocese de Mariana, Teologia da Libertação e Emergência do Movimento dos Atingidos por Barragens do Alto Rio Doce (MG)

The article analyzes the mobilization and networking of progressive religious groups in the Archdiocese of Mariana in Minas Gerais State and the influence of this process on the emergence and consolidation of the Movement of People Affected by Dams in the Alto Rio Doce and Zona da Mata regions of the state. We use the political process approach to explain ideological and institutional transformations within the Archdiocese and their influence on the organization of local populations. Documents and interview data demonstrate that a favorable political opportunity structure provided conditions which facilitated the diffusion of ideas and religious practices related to Liberation Theology. The interaction of religious activists contributed to the formation of social movement networks and mobilization structures which facilitated dissemination. Framing processes played an important role in facilitating the assimilation of these ideas by activists and applying them within a vision of building a more just society. Keywords: Archdiocese of Mariana; mobilization; people affected by dams; Liberation Theology; social movements.

Recuperação de área degradada com sistema agroflorestal no Vale do Rio Doce, Minas Gerais

O Vale do Rio Doce, MG, apresenta um histórico de ocupação e uso do solo que favorece a degradação ambiental, em que predominam pastagens sob o uso constante de queimadas. Os sistemas agroflorestais têm-se mostrado eficientes na recuperação de áreas degradadas. Neste estudo foram avaliados os efeitos de um sistema agroflorestal na recuperação do solo em área degradada por pastagem na comunidade de Ilha Funda, Município de Periquito, Minas Gerais. A implantação do sistema se deu em 1994 e está sendo conduzido segundo os princípios agroecológicos, potencializando a regeneração natural e a sucessão de espécies. Em 1998, foram coletadas amostras de solo na área em recuperação e em duas áreas adjacentes: uma área degradada, que se encontrava em condições semelhantes às da área em recuperação no início do processo, e outra ocupada por pastagem. Foram determinados atributos químicos do solo e realizada a caracterização da matéria orgânica. O solo da área em recuperação com sistema agroflorestal mostrou-se em melhores condições do que o solo sob pastagem e o da área degradada, apresentando maior dinâmica do carbono orgânico e maior disponibilidade de nutrientes. Embora o teor de carbono orgânico total apresentado pelo solo sob pastagem tenha sido maior que nas demais condições avaliadas, o solo do sistema agroflorestal já está se igualando ao da pastagem no acúmulo das formas mais estáveis de carbono e apresentando maior dinâmica das frações orgânicas menos estáveis. Este estudo comprovou a eficiência dos sistemas agroflorestais, conduzidos segundo os princípios agroecológicos, na recuperação de áreas degradadas.

Valer (vá ler?): formação de trabalhadores sob a ideologia do mercado na universidade corporativa da Vale

Este artigo tem como objetivo discutir a concepção de educação dos projetos de formação profissional promovidos pela Valer, a Universidade Corporativa da Companhia Vale do Rio Doce (atual Vale). O controle sobre a formação dos trabalhadores assume um papel estratégico para a otimização dos resultados organizacionais. Entretanto, demandado pelo mercado, o aumento da oferta de escolaridade para a satisfação das demandas da reestruturação produtiva dista de uma perspectiva de formação omnilateral, sendo marcada, ao contrário, pela lógica do imediatismo e da instrumentalização, além da adesão à cultura organizacional e captura da subjetividade. Sob a ótica das competências necessárias para a execução das tarefas, o trabalho vem se deteriorando e, com ele, o trabalhador. A investigação está referendada no materialismo histórico, que comporta a tarefa de desvendar a realidade fragmentada e articulada com o senso comum. Como instrumento analítico, utilizamos a análise do discurso.

Primeiro registro documentado de Formicarius colma Boddaert, 1783 (Aves: Formicariidae) para o Parque Estadual do Rio Doce, Minas Gerais, utilizando armadilhas fotográficas

The Rufous-capped Antthrush, Formicarius colma Boddaert, 1783, is a ground dwelling species of bird commonly associated with moist forests. With a wide range in South America, it is nevertheless considered a rare species within the Brazilian state of Minas Gerais. During a camera-trapping study in the Parque Estadual do Rio Doce, spanning a 17 month period (2,825 trap nights) a photograph of this species was obtained. This record provides concrete proof that the species inhabits the park and validates previous visual and song records for this species. It also demonstrates that camera traps can be a useful tool in obtaining records of cryptic bird species.

U–Pb zircon and 40Ar–39Ar K‐feldspar dating of syn‐sedimentary volcanism of the Neoproterozoic Maricá Formation: constraining the age of foreland basin inception and inversion in the Camaquã Basin of southern Brazil

ABSTRACTNew U–Pb zircon and 40Ar–39Ar K‐feldspar data are presented for syn‐sedimentary volcanogenic rocks from the Neoproterozoic Maricá Formation, located in the southern Brazilian shield. Seven (of nine) U–Pb sensitive high‐resolution ion microprobe analyses of zircons from pyroclastic cobbles yield an age of 630.2±3.4 Ma (2σ), interpreted as the age of syn‐sedimentary volcanism, and thus of the deposition itself. This result indicates that the Maricá Formation was deposited during the main collisional phase (640–620 Ma) of the Brasiliano II orogenic system, probably as a forebulge or back‐bulge, craton‐derived foreland succession. Thus, this unit is possibly correlative of younger portions of the Porongos, Brusque, Passo Feio, Abapã (Itaiacoca) and Lavalleja (Fuente del Puma) metamorphic complexes. Well‐defined, step‐heating 40Ar–39Ar K‐feldspar plateau ages obtained from volcanogenic beds and pyroclastic cobbles of the lower and upper successions of the Maricá Formation yielded 507.3±1.8 Ma and 506.7±1.4 Ma (2σ), respectively. These data are interpreted to reflect total isotopic resetting during deep burial and thermal effects related to magmatic events. Late Middle Cambrian cooling below ca. 200 °C, probably related to uplift, is tentatively associated with intraplate effects of the Rio Doce and/or Pampean orogenies (Brasiliano III system). In the southern Brazilian shield, these intraplate stresses are possibly related to the dominantly extensional opening of a rift or a pull‐apart basin, where sedimentary rocks of the Camaquã Group (Santa Bárbara and Guaritas Formations) accumulated.

Diversity and antifungal susceptibility of yeasts from tropical freshwater environments in Southeastern Brazil

Yeast communities were isolated from water and sediment samples of two unpolluted natural lakes, located inside Rio Doce State Park, and two rivers located outside of this Park in Southeastern Brazil. A total of 134 yeast isolates were obtained and identified as belonging to 36 species. The numbers of fecal coliforms and yeast species were higher in rivers than in lakes. The genus Candida had the highest number of species with the presence of opportunistic pathogens such as Candida krusei, C. tropicalis, C. guilliermondii and C. parapsilosis. Yeasts able to grow at 37 °C were tested in relation to their susceptibility to common used antifungal drugs. Yeast isolates (13%) were susceptible to ketoconazole, 79% to fluconazole, 31% to terbinafine and 78% of the strains were susceptible to amphotericin B. Seven isolates from different Candida species were resistant to all antifungals tested. The high number of fecal coliforms found in these aquatic environments and the presence of resistant yeast strains to common used antifungal drugs suggest that these environments can pose potential health risks for people utilizing the contaminated waters.

Host Plant Record for the Fruit Flies,Anastrepha fumipennisandA. nascimentoi(Diptera, Tephritidae)

The first host plant record for Anastrepha fumipennis Lima (Diptera: Tephritidae) in Geissospermum laeve (Vell.) Baill (Apocynaceae) and for A. nascimentoi Zucchi found in Cathedra bahiensis Sleumer (Olacaceae) was determined in a host plant survey of fruit flies undertaken at the “Reserva Natural da Companhia Vale do Rio Doce”. This reserve is located in an Atlantic Rain Forest remnant area, in Linhares county, state of Espírito Santo, Brazil. The phylogenetic relationships of Anastrepha species and their hosts are discussed. The occurrence of these fruit fly species in relation to the distribution range of their host plants is also discussed.

Frações da matéria orgânica do solo após três décadas de cultivo de eucalipto no Vale do Rio Doce-MG

As mudanças nas distintas frações da matéria orgânica do solo (MOS) sob cultivo do eucalipto são pouco conhecidas. Assim, o presente trabalho teve como objetivo avaliar o impacto do cultivo do eucalipto nos estoques de C das diversas frações da MOS, em solos ocupados anteriormente por pastagens degradadas, bem como verificar qual fração da MOS constitui-se um indicador mais sensível à mudança de uso do solo. O estudo foi realizado em plantações comerciais de eucalipto em dois locais na região do Vale do Rio Doce-MG (Belo Oriente e Virginópolis), onde foram determinados em amostras dos solos: C orgânico total (COT), C da fração leve (leve livre - FLL e leve oclusa - FLO), da fração pesada (areia - AR, silte + argila - S + A e argila - ARG), da biomassa microbiana (BM) e das frações húmicas (ácidos fúlvicos - FAF, ácidos húmicos - FAH e huminas - FH). Os resultados indicaram que, de maneira geral, os solos sob os diferentes tipos de uso em Virginópolis, em virtude da menor temperatura média anual e maior teor de argila, apresentaram maiores estoques de C em todas as frações da MOS em relação a Belo Oriente. Assim, o seqüestro de C no solo pelo cultivo do eucalipto foi maior em Virginópolis (14,2 t ha-1) que em Belo Oriente (10,0 t ha-1), resultando numa taxa de seqüestro de C de aproximadamente 0,42 e 0,29 t ha-1 ano-1 , respectivamente. Em Belo Oriente, o cultivo do eucalipto favoreceu o aumento no estoque de C das frações ARG, S + A e FH no solo. Comportamento semelhante foi observado para o C das FLL, FAF e FAH, em Virginópolis. Dentre todas as frações da MOS analisadas, a BM e a FLO foram indicadores menos sensíveis às alterações na MOS após três décadas da mudança de uso do solo. Com isso, o COT e a fração leve livre, ácidos fúlvicos, ácidos húmicos e humina foram mais eficientes nesse sentido.

Role of atelomixis in replacement of phytoplankton assemblages in Dom Helvécio Lake, South-East Brazil

Scale and frequency of changes in a lake’s physical structure, light dynamics, and availability of nutrients are closely related to phytoplankton ecology. Since phytoplankton assemblages were first described, phytoplankton ecologists concluded that these assemblages provide insight into phytoplankton responses to environmental changes. Objectives of this study were to investigate ecology of phytoplankton during a complete hydrological cycle in the deepest natural lake in Brazil, Dom Helvécio, and to sort species into the list of assemblages, checking its accordance with environmental changes in a tropical system within the middle Rio Doce Lake district, South-East Brazil. Canonical Correspondence Analysis, t-test, Mann–Whitney U-test, and Kruskal–Wallis test were used to analyze climatological, environmental, and plankton data, which were obtained monthly in 2002. A new phytoplankton assemblage, NA (atelomixis-dependent desmids), is suggested because atelomixis (robust movement of water occurring once a day) contributed to replacement of species in Dom Helvécio Lake. Stability of stratification, water chemistry, and composition of phytoplankton assemblages characterized two periods. The first period occurred in six rainy months (Jan–Mar and Oct–Dec) when the lake was stratified and phytoplankton was dominated by two assemblages: NA and F. The second period occurred in six dry months (Apr–Sep) when the lake was nonstratified and phytoplankton was dominated by four assemblages: S2, X1, A, and LO. Results suggest that phytoplankton in Dom Helvécio Lake was shaped by seasonal and daily changes of water temperature, even with its lower amplitude of variation within 2002 (El Niño year). These changes promoted water column stratification or mixing, reduced light, and increased nutrient availability. Temperature, therefore, is similarly important to phytoplankton ecology in tropical regions as it is in temperate ones. Sorting phytoplankton species into assemblages matched well with environmental changes and periods identified so it is also suggested that this can be further used as an appropriate tool to manage water quality when evaluating tropical lakes.

Conteúdo alimentar em macrófitas aquáticas carnívoras: Utricularia foliosa L. e U. hydrocarpa Vahl. (Tubiflorae, Lentibulariaceae)

Qualitative and quantitative aspects of the feeding contents of Utricularia foliosa and U. hydrocarpa (Tubiflorae, Lentibulariaceae) were studied in order to assess the impact of these macrophytes in the control of the aquatic organisms populations. The macrophytes were collected in Lagoa Amarela and Lagoa da Barra around Parque Estadual do Rio Doce in the state of Minas Gerais. The feeding contents of the utricle were compared to the perifiton (microalgae) and zooplankton associated to the macrophytes stems and the phytoplankton free in the water column. The obtained results indicated that the two species of Utricularia used exclusively the periphyton and did not use the food particles available in the water column. The high densities of the periphyton inside the utricle ( U. foliosa = 362 to 1062 org/mm 2 and U. hydrocarpa = 79 to 968 org/mm 2 ) suggest that the plants can play a potential control on the population of sessile organisms but probably have little influence on the plankton limnetics populations.

Fruit flies (Diptera, Tephritidae) and their associations with native host plants in a remnant area of the highly endangered Atlantic Rain Forest in the State of Espírito Santo, Brazil

The results presented in this paper refer to a host survey, lasting approximately three and a half years (February 2003-July 2006), undertaken in the Vale do Rio Doce Natural Reserve, a remnant area of the highly endangered Atlantic Rain Forest located in Linhares County, State of Espírito Santo, Brazil. A total of 330 fruit samples were collected from native plants, representing 248 species and 51 plant families. Myrtaceae was the most diverse family with 54 sampled species. Twenty-eight plant species, from ten families, are hosts of ten Anastrepha species and of Ceratitis capitata (Wiedemann). Among 33 associations between host plants and fruit flies, 20 constitute new records, including the records of host plants for A. fumipennis Lima and A. nascimentoi Zucchi. The findings were discussed in the light of their implications for rain forest conservation efforts and the study of evolutionary relationships between fruit flies and their hosts.

PERMANENT GENETIC RESOURCES: Characterization of eight microsatellite loci in the woolly mouse opossum, Micoureus paraguayanus, isolated from Micoureus demerarae

Eight novel microsatellite markers were isolated from the woolly mouse opossum from the Amazon Forest in Peru, Micoureus demerarae, using a partial genomic DNA library and an enrichment protocol. These loci were polymorphic in M. demerarae and Micoureus paraguayanus populations from the Atlantic Forest in Brazil with the number of alleles ranging from two to 23. Those eight loci plus another five already described for M. paraguayanus will allow for the evaluation of genetic diversity of populations from the 'Rio Doce' Park, one of the last Atlantic Forest fragments in Minas Gerais state, Brazil.

Influência de fatores edáficos sobre variações florísticas na Floresta Estacional Semidecídua no entorno da Lagoa Carioca, Parque Estadual do Rio Doce, MG, Brasil

O presente trabalho teve como objetivos determinar se a distribuição de espécies arbóreas e de suas densidades, no entorno da Lagoa Carioca do Parque Estadual do Rio Doce, MG (19º48'18" - 19º29'S e 42º38' - 42º28'18"W), poderiam estar correlacionadas com fatores edáficos e indicar espécies para a recuperação de matas ciliares. Foram alocados dois blocos de 50 parcelas de 10×10 m, sendo um em relevo de menor declividade e outro de maior declividade. Forma amostrados todos os indivíduos com circunferência do tronco a 130 cm do solo (CAP) maior ou igual a 15 cm. Foi coletada uma amostra simples de solo por parcela na profundidade de 0 a 20 cm. A partir de grupos de dez parcelas formou-se uma amostra composta, que foi submetida à análise química e granulométrica. A ordenação dos dados de solo e vegetação foi realizada pela análise de correspondência canônica (CCA) que indicou serem os fatores edáficos os responsáveis pela ordenação das espécies. Xylopia emarginata Mart., Calophyllum brasiliense Cambess., Tapirira guianensis Aubl., Tabebuia chrysotricha (Mart. ex Dc.) Standl., Protium heptaphyllum (Aubl.) Marchal e Cecropia hololeuca Miq. ocorreram restritamente na área de depleção ciliar e foram indicadas para reflorestamento de matas ciliares, uma vez que apresentaram grande resistência e predileção por ambientes úmidos.

Larval ecomorphology of 13 Libellulidae (Anisoptera, Odonata) of the Middle Rio Doce Valley, Minas Gerais, Brazil

In the lakes of the Middle Rio Doce, Minas Gerais (MG), two groups of larval Libellulidae are distinguished by preferences of habitat use: one uses mainly aquatic macrophytes and the other uses the bottom substrate. The goal of this work was to verify if there is a morphological distinction between the two groups of species. Thirteen body measures were taken from the larvae and analyzed. No difference was found between the two groups of species regarding the body size, but shape differences were observed for two morphological variables. The species that use mainly macrophytes tend to have larger relative measures of the labium and smaller measures of the abdomen width. Advantages in resource obtainment and in vulnerability to predation are probably the explanations for the morphological divergence among these larval groups.

Solos com morfologia latossólica e caráter câmbico na região de Governador Valadares, Médio Rio Doce, Minas Gerais: gênese e micromorfologia

Nas regiões do Médio Vale do Rio Doce marcadas por fortes alterações seco-úmidas sazonais do clima, coexistem Latossolos, Cambissolos e Argissolos, com maior fertilidade nos últimos. Observações gerais da região indicam Latossolos com certa reserva em minerais primários, conferindo-lhes caráter câmbico, bem como Cambissolos com morfologia latossólica. Neste trabalho, foram estudadas a gênese e características pedológicas de Latossolos, Cambissolos associados e um Argissolo, em duas toposseqüências na microbacia do córrego do Desidério, no Planalto Soerguido/maciço montanhoso do divisor Suaçui Pequeno/Corrente Grande, região noroeste do município de Governador Valadares. Além de características químicas e físicas de rotina, foram investigadas as feições micromorfológicas de seis perfis de solos em duas toposseqüências e feitos exames microquímicos por microscopia eletrônica (EDS) nos diversos tipos de minerais amostrados. Tanto os Latossolos quanto os Cambissolos mostraram microestrutura granular típica, com relação silte/argila abaixo do limite requerido para diferenciar Latossolos de Cambissolos. O processo de coluvionamento associado à encosta onde há afloramento de rochas enriquece os solos a jusante, conferindo características câmbicas. Mesmo nos Latossolos mais profundos ocorrem alguns grãos residuais de feldspato potássico e, principalmente, micas degradadas, indicando relativa reserva de K não-trocável nestes solos. Nos Cambissolos latossólicos estudados há diversidade mineralógica muito maior na fração grosseira, com a coexistência de minerais instáveis (biotita, anfibólio, feldspato) e minerais resistentes (minerais de Ti, gibbsita), denotando a intensa pedoturbação atuando sobre o material coluvial proveniente de afloramentos de rochas a montante. As áreas de Cambissolos com morfologia latossólica são preferencialmente utilizadas com cultivos de subsistência, devido à maior fertilidade química e profundidade destes solos.

A phylogenetic analysis of Brycon and Henochilus (Characiformes, Characidae, Bryconinae) based on the mitochondrial gene 16S rRNA

The genus Brycon, the largest subunit of the Bryconinae, has 42 valid species distributed from southern Mexico to the La Plata River in Argentina. Henochilus is a monotypic genus, comprising a single species (H. wheatlandii) found in the upper Rio Doce basin. In the present study, partial sequences of the mitochondrial gene 16S were obtained for fifteen species of Brycon and for Henochilus wheatlandii. The results showed that the genus Brycon is paraphyletic, since Henochilus is the sister-group of B. ferox and B. insignis. The most basal species analyzed were the trans-Andean species B. henni, B. petrosus, and B. chagrensis.

Zoneamento agroclimático da cultura do café para a Bacia do Rio Doce

Objetivou-se neste trabalho, através da geoespacialização, a identificação das regiões aptas, restritas e inaptas ao cultivo do café (Coffea arabica L.) na Bacia do Rio Doce. Utilizou-se para tal, dados de temperatura e déficit hídrico de 50 estações meteorológicas instaladas na bacia e em bacias limítrofes. Os dados de déficit hídrico foram determinados utilizando o balanço hídrico segundo Thornthwaite & Mather (1955). Foram identificadas regiões equivalentes a um terço da bacia, localizadas na parte central e no nordeste da mesma, como sendo inaptas ao cultivo do café, conforme os critérios de produtividade relacionados com as exigências térmicas e hídricas da cultura.

40Ar/39Ar ages (600-570 Ma) of the Serra do Azeite transtensional shear zone: evidence for syncontractional extension in the Cajati area, southern Ribeira belt

This paper presents 40Ar/39Ar ages of the rocks from the Serra do Azeite transtensional shear zone in the southern part of the Ribeira belt, between the States of São Paulo and Paraná, and also discusses the regional correlations and the tectonic implications for other parts of the belt. The geochronological data suggest that transtensional deformation was active between 600 and 580 Ma (hornblende and muscovite apparent ages, respectively). This time span is considerably older than previous proposals for the period of activity of these structures (520-480 Ma) in the northern segment of this belt and in the Araçuaí belt. Kinematic analysis of the dated mylonites shows extensional structures with top-down movement to ESE compatible with structures found in other tectonic segments in the eastern portion of the Quadrilátero Ferrífero and in the Rio Doce Valley region. Our ages are situated in the same time interval defined for the alkaline magmatism of the Serra do Mar suite. We suggest that the regional tectonic framework was developed during continental-scale extension. This process has been coeval with convergent strain in the adjacent Neoproterozoic shear zones of the Apiaí/Ribeira and Araçuaí belts, which make up significant segments of these belts. The available data show that these structures may not be simply related to post-orogenic gravitational collapse, but must involve a more complex process probably related to dynamic balance between crustal thickening and thinning during tectonic convergence, basin formation and exhumation processes.