Larviculture of piabanha‑do‑pardo in aquariums of different colors

O objetivo deste trabalho foi avaliar o efeito de diferentes cores de aquários na larvicultura da piabanha‑do‑pardo (Brycon sp.). Os tratamentos consistiram na utilização de aquários de cores claras (branca, verde e azul) e escuras (marrom e preta). Ao final do experimento, foram mensurados a sobrevivência, o peso, o comprimento total e a coloração das larvas, que foram comparados pelo teste de Tukey, a 5% de probabilidade. A sobrevivência foi menor (66,25%), com maior taxa de canibalismo (17,08%), no aquário de cor azul, quando comparado ao aquário de cor marrom (84,17%), com baixa taxa de canibalismo (6,25%). O comprimento total, o peso e a mortalidade não diferiram entre os tratamentos. A coloração das larvas escureceu progressivamente dos aquários mais claros para os mais escuros, o que interferiu no canibalismo e na sobrevivência. O aquário marrom promove maior valor de sobrevivência e menor taxa de canibalismo nas larvas de piabanha‑do‑pardo.The objective of this work was to evaluate the effect of different colors of aquariums on the larviculture of piabanha‑do‑pardo (Brycon sp.). The treatments consisted of the use of light‑ (white, green, and blue) and dark‑ (brown and black) colored aquariums. At the end of the experiment, survival, weight, total length, and color of the larvae were measured and compared by the Tukey test, at 5% probability. Survival was lower (66.25%), with a higher rate of cannibalism (17.08%), in the blue‑colored aquarium when compared to the brown‑colored one (84.17%), with a low rate of cannibalism (6.25%). Total length, weight, and mortality did not differ among treatments. The color of the larvae gradually darkened from the lighter to the darker aquariums, which interfered with cannibalism and survival. The brown aquarium promotes a greater survival value and a lower rate of cannibalism in larvae of piabanha‑do‑pardo

Organic matter composition and paleoclimatic changes in tropical mountain peatlands currently under grasslands and forest clusters

Tropical peatlands are important ecosystems for Planet Earth, as they store large amounts of carbon and water. A better understanding of the impact of vegetation type and altitude in content, composition, and rate of accu mulation of organic matter is key for assessing the current role of such environments. This study evaluated fibric and soluble fractions as well as the lignocellulosic and the isotopic compositions of the peat organic matter from four tropical mountain peatlands located at different altitudes of the Serra do Espinhaço Meridional, state of Minas Gerais, Brazil. The peatlands are currently under grasslands and forest clusters. Samples of peat under both vegetation types were collected and analyzed for organic matter fractions, cellulose, and lignin (van Soest method), as well as carbon and nitrogen isotopes. Different depths were chosen for radiocarbon dating of se lected samples. The organic matter of peatlands currently under grasslands and forest clusters presented dif ferences in soluble fractions, lignocellulosic composition, and δ13C values. Multivariate analyses allowed grouping the peatlands by altitude and vegetation type. The chronological succession of grassland and forest clusters in tropical mountain peatlands was influenced by altitude and was related to paleoclimatic changes.info:eu-repo/semantics/publishedVersio

Hydrology and carbon flow in mountain tropical peatlands

?rea de concentra??o: Produ??o Vegetal.O presente trabalho foi realizado com apoio da Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG) (Processos CAG ? APQ ? 01614-14 e CAG - PPM - 00568-16).O presente trabalho foi realizado com apoio da Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - Brasil (CAPES) - C?digo de Financiamento 001.Turfeiras s?o ecossistemas formados pela acumula??o de tecidos vegetais em ambientes com condi??es anaer?bicas. Suas principais caracter?sticas definidoras s?o o solo org?nico e a reten??o de ?gua. S?o as propriedades hidrol?gicas das turfeiras que permitem a sua exist?ncia continuada. Entender a hidrologia das turfeiras ? fundamental para estes ecossistemas, j? que ? provavelmente a condi??o mais importante relacionada ? ecologia, ao desenvolvimento, ?s fun??es e aos seus processos de forma??o. O objetivo deste estudo foi avaliar o comportamento hidrol?gico e o fluxo de carbono em turfeiras tropicais de montanha e a influ?ncia da antropiza??o nestes ecossistemas. Foram instalados sete medidores de n?vel em duas turfeiras situadas no Chapad?o do Couto (MG), com intervalo de registro de trinta minutos, sendo quatro em turfeira protegida pelo Parque Estadual do Rio Preto e tr?s em uma turfeira antropizada do alto curso do rio Ara?ua?, utilizada para pastejo animal e que sofre queimadas frequentes. Tamb?m foram coletadas, a cada dois meses, amostras de ?gua em tr?s pontos em cada turfeira, nas quais foram analisados: S?lidos sol?veis totais; Potencial de oxidorredu??o; temperatura; pH; oxig?nio dissolvido; condutividade el?trica; demanda qu?mica de oxig?nio; turbidez; cloro total; f?sforo; pot?ssio; ferro total; Alum?nio; nitrato; am?nia e carbono org?nico total. No exut?rio da ?rea de recarga h?drica de cada turfeira foi medida a vaz?o, tamb?m a cada dois meses. Par?metros clim?ticos da ?rea dos estudos foram obtidos com instala??o de uma esta??o meteorol?gica com registros tomados a cada hora. Com os dados obtidos pelos medidores de n?vel foram calculados a amplitude de varia??o e varia??o do len?ol fre?tico. Tamb?m foi calculado o rendimento espec?fico para as turfeiras estudas, relacionando a precipita??o e a varia??o na eleva??o do len?ol fre?tico. Os dados foram analisados por fatorial/componente principal para se obter os principais processos influenciadores da qualidade da ?gua em cada turfeira. Os valores de rendimento especifico foram correlacionados com a vaz?o em cada turfeira. Tamb?m foi usada regress?o m?ltipla para obter uma equa??o que melhor representasse a vaz?o em cada ?rea. A estat?stica multivariada permitiu a identifica??o de processos que influenciam a qualidade da ?gua, sendo que em ?reas protegidas, o principal processo influenciador da qualidade das ?guas de suas turfeiras ? a decomposi??o da mat?ria org?nica e as turfeiras em ?reas sem prote??o a qualidade da ?gua ? influenciada pela eros?o da ?rea de recarga. A prote??o das turfeiras ainda reduz a varia??o do len?ol fre?tico, al?m de torna-las mais produtivas, em rela??o a quantidade de ?gua por unidade de ?rea e protege sua capacidade de reten??o de ?gua dos efeitos antr?picos, principalmente inc?ndios. Turfeiras tropicais de montanha s?o bastante sens?veis a antropiza??o, que provoca redu??o do estoque de carbono, diminui??o do volume de ?gua armazenado e degrada??o da qualidade de suas ?guas. Desta forma, a preserva??o ? de fundamental import?ncia para estes ecossistemas.Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Tese (Doutorado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2018.Peatlands are ecosystems formed by the accumulation of litter in environments with anaerobic conditions. Its main defining characteristics are organic soil and water retention. Therefore, it is the hydrological properties of peatlands that allow its continued existence. Understand the hydrology of peatlands is critical to these ecosystems, since it is probably the most important condition related to ecology, development, functions and their formation processes. The aim of this study was to evaluate the hydrological process and the dynamic of carbon in a mountain tropical peatlands and the influence of anthropization on these ecosystems. Seven level meters were installed in two peatlands located in Chapad?o do Couto (MG), with a record interval of thirty minutes, four of which were in protected peatland by the State Park of Rio Preto and three in an anthropic peatland of the upper Ara?ua? River, used for animal grazing and suffering frequent burnings. Also, water samples were collected every two months at three points in each peatland, in which where analyzed: Total soluble solids; oxidoreduction potential; temperature; pH; dissolved oxygen; electric conductivity; chemical oxygen demand; turbidity; total chlorine; phosphor; potassium; total iron; Aluminum; nitrate; ammonia and total organic carbon. In the exutory area of the water recharge area of each peatland was measured, also every two months. Climatic parameters of the study area were obtained with the installation of a meteorological station with records taken every hour. With the data obtained by the piezometers were calculated the amplitude of variation and variation of the water table. It was also calculated the specific yield for the peatland studied, relating the precipitation and the variation in the elevation of the water table. The data were analyzed by factorial/component analysis to obtain the main processes influencing the water quality in each peatland. Multiple regression was also used to obtain an equation that best represents the flow in each area. Multivariate statistics allowed the identification of processes that influence water quality. In protected areas, the main process influencing the quality of the water in the peatlands is the decomposition of organic matter and the peatland in unprotected areas. influenced by the erosion of the recharge area. The protection of peatlands still reduces the variation of the water table, in addition to making them more productive, in relation to the amount of water per unit area and protects their capacity of water retention of anthropic effects, mainly fires. Mountain tropical peatlands are quite sensitive to anthropization, which causes carbon stock reduction, decreased volume of stored water, and degraded water quality. In this way, preservation is of fundamental importance for these ecosystems

Effects of sources and doses of humic acids in bean production (Phaseolus vulgaris L.)

A mat?ria org?nica (MOS) do solo consiste de uma mistura de compostos em v?rios est?gios de decomposi??o, resultante da degrada??o biol?gica de res?duos de plantas e animais, e da atividade de microrganismos, denominados subst?ncias h?micas (SHs). Essas subst?ncias fracionadas em ?cidos f?lvicos (AF), ?cidos h?micos (AH) e humina (H), de acordo com sua solubilidade em meio ?cido ou b?sico. Os AH t?m sido usados como fertilizantes aplicados diretamente no solo ou via foliar, principalmente por influenciarem o metabolismo das plantas. Objetivou-se com este trabalho avaliar em feijoeiro (Phaseolus vulgaris L.), a influ?ncia de fontes e doses diferentes de AH, na produ??o, crescimento radicular e absor??o de nutrientes e biodisponibilidade de nutrientes no solo. O experimento foi conduzido utilizando o delineamento em blocos casualizados com 15 tratamentos, sendo estes as fontes de AH (turfa - 1, composto - 2 e produto comercial - 3) e as doses de AH (0, 2, 8, 16 e 32 kg ha-1), com quatro repeti??es. Foram avaliadas: altura das plantas (cm), di?metro do caule (cm), teor de clorofila (?g cm-2) e teor de macro e micronutrientes nas folhas no florescimento do feijoeiro e ao fim do experimento, peso de sementes (g), massa seca da parte a?rea e de ra?zes (g), n?mero de vagem por planta e de sementes por vagem e no solo: pH em ?gua e teores de mat?ria org?nica, P, K, Ca, Mg, Al e H+Al. A aplica??o de AH reduziu o crescimento e produ??o de gr?o, com aumento das doses em cada fonte, seguindo a ordem fonte 3 > fonte 1 > fonte 2. Os teores de P, K, Cu, Fe, Mn e Zn nas folhas foram influenciados pelas doses de todas as fontes de AH. Houve redu??o para maioria dos nutrientes quantificados nas folhas com aumento das doses de AH. Os teores de P e K se elevaram no solo, com a aplica??o de AH. Para condi??es testadas, n?o se recomenda utiliza??o de AH para cultura do feijoeiro.Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2015.The soil organic matter (SOM) consists of a mixture of compounds in many decomposition stages, the result of biological degradation of residues of plants and animals, and microorganisms activity, called humic substances (HS). These substances are fractionated into fulvic acids (FA), humic acids (HA) and humin (H), according to their solubility in acidic or basic medium. HA have been used as fertilizers directly applied to the soil or via foliar, mainly because they influence plants metabolism. The main goal of this study was evaluating, in bean plant (Phaseolus vulgaris L.), the influence of sources and different doses of HA in production, root growth, nutrients absorption and bioavailability of nutrients in the soil. The experiment was conducted using randomized block design with 15 treatments, which are the sources of HA (peat ? 1, compound ? 2 and commercial product ? 3) and doses of HA (0, 2, 8, 16 e 32 kg ha-1), with four repetitions. Evaluations were made on: plants height (cm), stem diameter (cm), chlorophyll content (?g cm-2) and content of macro and micronutrients in the leaves in the flowering stages and in the end of the experiment, seeds weight (g), dry matter of the aerial part and roots (g), number of pods per plant and seeds per pod, and in the soil: pH in water and contents of organic matter, P, K, Ca, Mg, Al and H+Al. Application of HA reduced bean growth and production, with increase of doses in each source, following order: source 3 > source 1 > source 2. Contents of P, K, Cu, Fe, Mn and Zn in the leaves were influenced by the doses of all HA sources. Most of the nutrients quantified in the leaves were reduced with increasing HA doses. Contents of P and K were increased in the soil with application of HA. For tested conditions, the use of HA for bean culture is not recommended

Larvicultura de piabanha-do-pardo em aquários de cores diferentes

O objetivo deste trabalho foi avaliar o efeito de diferentes cores de aquários na larvicultura da piabanha-do-pardo (Brycon sp.). Os tratamentos consistiram na utilização de aquários de cores claras (branca, verde e azul) e escuras (marrom e preta). Ao final do experimento, foram mensurados a sobrevivência, o peso, o comprimento total e a coloração das larvas, que foram comparados pelo teste de Tukey, a 5% de probabilidade. A sobrevivência foi menor (66,25%), com maior taxa de canibalismo (17,08%), no aquário de cor azul, quando comparado ao aquário de cor marrom (84,17%), com baixa taxa de canibalismo (6,25%). O comprimento total, o peso e a mortalidade não diferiram entre os tratamentos. A coloração das larvas escureceu progressivamente dos aquários mais claros para os mais escuros, o que interferiu no canibalismo e na sobrevivência. O aquário marrom promove maior valor de sobrevivência e menor taxa de canibalismo nas larvas de piabanha-do-pardo

Natural and anthropogenic gamma-ray emitters and iron-bearing compounds distribution in peatlands of the southern Espinhaço mountain chain, Brazil

To help understand the dynamics of peatlands forming on the Southern Serra do Espinhaco, Brazil, the occurring natural (²²⁶Ra, ²³²Th, ⁴⁰K) and anthropogenic (¹³⁷Cs) activity of gamma-ray emitters located at three sites, namely the localities of Sao Joao da Chapada (CH), Pinheiro (PIN) and Pau de Fruta (PDF), was studied. The iron compounds were characterized by ⁵⁷Fe Mossbauer spectroscopy. Differences on natural radionuclide levels and distributions were found among the peatland sites, indicating differences on mineral composition, hydric regimes and living. Significant correlation was found only for ²³²Th–²²⁶Ra activity values (Pearson correlation coefficient of − 0.5), which is different from other South American soils, where significant positive correlations among all radionuclides were determined. In PDF and CH, the dose rate results are lower than the worldwide mean value, but in PIN, they are higher because of the relatively high ²²⁶Ra concentration. The only anthropogenic radionuclide is ¹³⁷Cs. The convection–diffusion model fits the CH and PDF activity profiles, although the PIN profile is likely affected by other soil mechanisms as well. Mossbauer spectra reveal Fe³⁺ in two different local environments and the occurrence of hematite in the upper samples of the CH site. The iron concentration decreases with depth. Contrary to soils of other regions, no significant correlation was found between iron species and the natural radioactivity. The studied peatlands exhibit clear differences between their natural and anthropogenic radionuclide distributions to those of mineral soils.Instituto de Física La PlataFacultad de Ingenierí