Prevalence of inadequacy and associated indicators with mineral intake in Brazilian adolescents and young adults / Prevalência de inadequação e fatores associados à ingestão adequada de minerais em adolescentes e adultos jovens brasileiros

ABSTRACT Objective To describe the prevalence of inadequate mineral intake and associated factors with calcium, iron, zinc, magnesium, phosphorus, and sodium intakes in individuals aged 15-24.9 years. Methods We analyzed 476 individuals from the Brazilian Study of Nutrition and Health, stratified into two age groups (adolescents aged 15-18.9 years and young adults aged 19-24.9 years). Mineral intake was obtained from two 24-hour Dietary Recalls. The values of the Estimated Average Requirement and the Tolerable Upper Intake Levels were considered to calculate the prevalence of inadequacy. Multiple logistic regression was used to determine associated factors with mineral intake. Results Calcium and magnesium had the highest prevalence of inadequacy (>83%) in both sexes and age groups. Sodium intake was above Tolerable Upper Intake Levels for the majority of the population studied (>68%). The intake of all minerals was different between the sexes for the two age groups (p<0.01), and it was not different between age groups (p>0.05). The associated factors with mineral intake were sex (calcium, iron, phosphorus, and sodium), age group (calcium, magnesium, phosphorus, and sodium), and physical activity (calcium, iron, and magnesium), followed by socioeconomic level (zinc and sodium) and body weight status (iron and sodium). Conclusion The expressive portion of the studied population is at nutritional risk for calcium, magnesium, and sodium. Such data can contribute to the national public policy revision that is related to micronutrient intake and the adoption of healthier habits by adolescents and young adults.

RESUMO Objetivo Descrever as prevalências de inadequação e fatores associados à ingestão de cálcio, ferro, zinco, magnésio, fósforo e sódio em indivíduos dos 15 aos 24,9 anos. Métodos Foram analisados 476 indivíduos do Estudo Brasileiro de Nutrição e Saúde, estratificados em dois grupos etários (adolescentes de 15-18,9 anos e adultos jovens de 19-24,9 anos). A ingestão de minerais foi obtida por meio de dois recordatórios de 24hs. Os valores de Requerimento Médio Estimado e do Limite Superior Tolerável de Ingestão foram considerados para calcular as prevalências de inadequação. Regressão logística múltipla foi utilizada para determinar os fatores associados à ingestão de minerais. Resultados Cálcio e magnésio tiveram elevadas prevalências de inadequação (>83%) em pacientes de ambos os sexos e grupos etários. A ingestão de sódio foi acima Limite Superior Tolerável de Ingestão para a maioria da população estudada (>68%). O consumo de todos os minerais foi diferente entre os sexos para os dois grupos etários (p<0,01) e não foi diferente entre os grupos etários (p>0,05). Os fatores associados à ingestão dos minerais foram sexo (cálcio, ferro, fósforo e sódio), grupo etário (cálcio, magnésio, fósforo e sódio) e atividade física (cálcio, ferro e magnésio), seguidos por nível socioeconômico (zinco e sódio) e estado de peso corporal (ferro e sódio). Conclusão Expressiva parcela da população estudada encontra-se em risco nutricional para cálcio, magnésio e sódio. Esses dados podem contribuir para a revisão de políticas públicas nacionais que se relacionam à ingestão de micronutrientes e à adoção de hábitos mais saudáveis pelos adolescentes e adultos jovens.

Woody species distribution across a savanna-dry forest soil gradient in the Brazilian Cerrado / Distribuição de espécies arbóreas em gradiente de solo savana-floresta seca no Cerrado brasileiro

Although richness and distribution of woody species in the Cerrado physiognomies have been extensively studied, the shifts of woody species from savanna physiognomies to dry forests have not yet been addressed. Here, we investigate the effect of soil physical-chemical traits on the woody species turnover between adjacent cerrado stricto sensu and dry forest physiognomies. Woody species were surveyed, and soil and topographic variables measured, in 30 10×40 m plots systematically distributed, with 15 plots in each physiognomy. We found a spatially structured distribution of woody species, and differences of soil traits between cerrado stricto sensu and dry forest areas, mainly related to the aluminum saturation, base saturation, and available phosphorus. Aluminum saturation increased toward the savanna area, while base saturation increased toward the dry forest. Most woody species predominated in one physiognomy, such as Callisthene major in the cerrado stricto sensu and Anadenanthera colubrina in the dry forest. Only 20% of the species were widely distributed across both physiognomies or, not often, restricted to the intermediary values of the soil gradient. General results indicate that contrasting soil traits between cerrado stricto sensu and dry forest produce a strongly spatially organized and sharp transition in terms of species distribution between these physiognomies.

Embora a distribuição e a riqueza em espécies arbóreas nas fitofisionomias do Cerrado venham sendo bastante estudadas, a transição entre savanas e florestas deciduais ainda não foi abordada. Investigamos o efeito de características físico-químicas do solo sobre a distribuição de espécies arbóreas em região de contato entre cerrado sentido restrito e floresta estacional decidual (FED). As espécies arbóreas foram amostradas sistematicamente, e variáveis de topografia e características do solo foram medidas em 30 parcelas de 10×40 m, sendo 15 parcelas em cada fisionomia. A distribuição das espécies arbóreas foi espacialmente estruturada, e as características do solo diferiram entre as áreas de cerrado sentido restrito e FED, principalmente relacionadas à saturação de alumínio, saturação de bases e teores de fósforo. A saturação de alumínio aumentou em direção ao cerrado sentido restrito, enquanto a saturação de bases aumentou em direção à FED. A maioria das espécies arbóreas predominou em uma das fisionomias, como Callisthene major em cerrado sentido restrito e Anadenanthera colubrina em FED. Apenas 20% das espécies foram amplamente distribuídas em ambas as fisionomias ou, em poucos casos, restritas aos valores intermediários do gradiente de solo. Os resultados indicam um forte contraste de características do solo entre o cerrado sentido restrito e a FED, assim como uma transição acentuada e espacialmente organizada quanto à distribuição de espécies arbóreas.

Ingreso de nitrógeno y fósforo al lago Atitlán (Guatemala) vía deposición atmosférica / Input of Nitrogen and Phosphorus to Lake Atitlán (Guatemala) via atmospheric deposition

La deposición de nutrientes por vía atmosférica tiene graves impactos sobre la ecología de bosques y cuerpos de agua templados. Sin embargo, su importancia en cuerpos de agua neotropicales casi no ha sido estudiada. En este artículo se cuantifica la contribución de nitrógeno inorgánico disuelto (NID, [NO3--N + NH4+-N]) y fósforo inorgánico soluble (FIS, [PO4-3-P]) depositados en bulto sobre superficies húmedas por vía atmosférica hacia el lago Atitlán (Guatemala). Las cargas estimadas de NID y FIS consecuencia de la deposición atmosférica directa (depositada sobre la superficie del lago) fueron de 151.2 ton/año y 5.6 ton/año, respectivamente. Con estos resulta-dos, se estima que el aporte de FIS por deposición atmosférica al lago Atitlán es comparable al de sus principales ríos tributarios, y de casi el doble para el ingreso de NID. Las estimaciones para el lago Atitlán son mayores que lo reportado para otros lagos. Nuestro estudio proporciona información básica para entender la eutrofización del lago Atitlán, enfatizado en la importancia de la deposición atmosférica como contribuyente al deterioro de este cuerpo de agua. Además, demuestra la necesidad de extender este tipo de estudio a otras cuencas neotropicales y la importancia de minimizar este impacto.

Atmospheric nutrient deposition has serious impacts on the ecology of forests and temperate water bodies nevertheless its importance in Neotropical water bodies has hardly been studied. Here we quantify the contribution of bulk atmospheric deposition on wet surfaces of dissolved inorganic nitrogen (DIN,[NO3--N + NH4+-N])and soluble inorganic phosphorus (SIP, [PO4-3-P])into Lake Atitlán (Guatemala). The estimated NID and SIP loads from this direct deposition on the lake surface were respectively, 151.2 tons/year and 5.6 tons/year. With these results, we estimated that the SIP input from atmospheric deposition to Lake Atitlán is comparable to that from the lake's main tributary rivers, whereas for DIN entry this is almost twice as much. Estimates for Lake Atitlán are higher than those reported for many lakes. Our study provides basic information towards understanding the eutrophication of Lake Atitlán, emphasizes the importance of atmospheric deposition in this process and the need for additional studies to document the process in neotropical watersheds.

Root deformation affects mineral nutrition but not leaf gas exchange and growth of Genipa americana seedlings during the recovery phase after soil flooding / A deformação de raízes afeta a nutrição mineral mas não as trocas gasosas foliares e o crescimento de mudas de Genipa americana durante a fase de recuperação após o alagamento do solo

Root deformation (RD) caused by errors in the pricking out process are irreversible and very difficult to detect in container-grown seedlings at the time of planting in the field. The objective of this study was to evaluate the effects of RD on leaf gas exchange, growth, biomass allocation and mineral nutrition of G. americana seedlings during the recovery phase after soil flooding. Four-months-old seedlings, with and without RD, were flooded for 42 days and their recovery was evaluated 28 days after soil drainage. There were no significant interactions between RD and soil flooding for all leaf gas exchange, growth and mineral nutrition after soil drainage, with the exception of leaf P concentrations. In plants with no RD, the P concentration in leaves of non-flooded plants was significantly higher than that of plants with RD. Soil flooding and RD did not influence leaf or root N concentrations or whole-plant N content. RD increased the K concentration in the roots, but not in the leaves. Changes in the nutrient concentrations in leaves and roots indicate that RD may affect physiological performance of seedlings after planting in the field.

A deformação da raiz (RD) causada por erros no processo de repicagem é irreversível e difícil de detectar em mudas produzidas em embalagens no momento do plantio no campo. O objetivo deste estudo foi avaliar os efeitos do RD nas trocas gasosas foliares, crescimento, alocação de biomassa e nutrição mineral de mudas de G. americana na fase de recuperação após o alagamento do solo. Mudas com quatro meses de idade, com e sem RD, foram alagadas por 42 dias e a sua recuperação foi avaliada 28 dias após a drenagem do solo. Não houve interação significativa entre RD e alagamento do solo nas trocas gasosas foliares, crescimento e nutrição mineral após a drenagem, com exceção das concentrações de P foliar. Em plantas sem RD, a concentração de P nas folhas de plantas não alagadas foi significativamente maior que a das plantas com RD. O alagamento do solo e a RD não influenciaram as concentrações de N nas folhas e raízes, e no conteúdo de N na planta inteira. A RD aumentou a concentração de K nas raízes, mas não nas folhas. Alterações nas concentrações de nutrientes nas folhas e raízes indicam que a RD pode afetar o desempenho fisiológico das mudas após o plantio no campo.

Excess Calcium, Magnesium and Phosphorus Deposition in the Epigastric Artery of Dialysis Patients Undergoing Renal Transplantation

ABSTRACT Objective: Vascular calcification contributes to cardiovascular disease on dialysis patients. Arterial mineral content is modified but not well defined. We aim to define what is the concentration of calcium, magnesium and phosphorus in the epigastric artery of adult dialysis patients undergoing renal transplantation. Methods: All renal allograft recipients who underwent surgery at our centre between May 2003 and December 2005 and consented to be taken small samples of epigastric artery were included in our cross-sectional study. Histological, radiological and spectrometric methods were used to measure vascular calcification, deposits and concentrations of calcium, phosphorus and magnesium in epigastric artery, which were correlated with clinical and biochemical characteristics. Mineral vascular content was compared with corresponding samples from cadaveric renal donors free from renal disease (control group). Results: Calcium and magnesium concentrations in epigastric artery were much higher in recipients (n = 100) than in donors (n = 30). Histologically confirmed calcifications were more frequent in recipients. Calcium and magnesium content in epigastric artery were correlated directly with recipient age, pre-transplant serum P and Ca × P product. A high content of calcium and magnesium in this artery was observed in recipients with media and intimal calcification. Multivariate logistic regression showed that dialysis vintage > 3.5 years and calcium concentration in epigastric artery ≥ 4500 mg/kg wet weight were independent predictors of histological calcification. Conclusion: Excess mineral deposition is observed in the epigastric artery of dialysis patients, where the recipient's age, serum P, Ca × P product and time on dialysis play a decisive role.

Eficiencia de solubilización de fósforo de aislados nativos guatemaltecos de Pseudomonas fluorescens / Phosphorus solubilization efficiency of native Guatemalan isolates of Pseudomonas fluorescens

El fósforo (P) es un elemento esencial en la producción agrícola, pero debido a su compleja dinámica en el suelo, solo una pequeña cantidad es aprovechable para las plantas, ya que la mayoría del P se encuentra en formas insolubles, especialmente, en suelos Andisoles de origen volcánico. Los microorganismos con capacidad solubilizadora de fósforo (MSF) son una alternativa para transformar el P a formas solubles y aprovechables por las plantas; además de brindar múltiples beneficios ambientales. Este trabajo identificó y evaluó in vitro, aislados nativos de Pseudomonas fluorescens Mingula, obtenidos de regiones guatemaltecas con suelos Andisoles que limitan la producción agrícola por la alta fijación de P. Se realizaron cultivos in vitro de la bacteria en medio National Botanical Research Instituteís phosphate growth (NBRIP), con fosfato tricálcico Ca3(PO4)2 como fuente de P insoluble y se midió el índice de solubilización de fósforo (ISF). Un total de 35 aislados de P. fluorescensfueron identificados y confirmados por PCR específico. El análisis de relaciones genéticas con el marcador AFLP, mostró dos grupos: el grupo A incluyó a los aislados con ISF mayores a 1.75, mientras el grupo B incluyó a aquellos con ISF menor a 1.75. La comparación de ISF entre los aislados y departamentos, demostró diferencia estadísticamente significativa (p < .001), con el aislado Pf_33 como más eficiente. Debido al potencial de solubilización de los aislados nativos del grupo genético A (ISF > 1.75), estos se recomiendan para futuras investigaciones que determinen su respuesta a condiciones de campo y estrategias para el desarrollo de biofertilizantes.

Phosphorus (P) is an essential element in agricultural production, but due to its complex dynamics in the soil, only a tiny amount is usable by plants. This is because most P is in insoluble forms, especially in volcanic Andisol soils. Microorganisms with phosphorus solubilizing capacity (MSF) are an alternative for transforming P into soluble forms usable by plants and providing multiple environmental benefits. This research identified and evaluated in vitro native isolates of Pseudomonas fluorescens Mingula, obtained from Guatemalan regions with Andisol soils that limit agricultural production due to high P fixation. In vitro cultures of the bacteria were grown on the National Botanical Research Instituteís phosphate medium (NBRIP), with tricalcium phosphate Ca3(PO4)2 as a source of insoluble P, and We measured the phosphorus solubilization index (PSI). We identified and confirmed a total of 35 isolates of P. fluorescens by specific PCR. Using the AFLP marker, genetic relationship analysis showed two groups: group A included isolates with PSI greater than 1.75, while group B included those with FSI less than 1.75. Comparing of PSI between isolates and departments showed statistically significant dif-ferences (p < 0.001), respectively, with the Pf_33 isolate as the most efficient. Because of the high solubilization potential of the native isolates of genetic group A (FSI > 1.75), We recommend future research to determine their response to field conditions and strategies for biofertilizer development.

Evaluación anual del fitoplancton y su respuesta a la calidad de agua en el lago de Amatitlán, Guatemala / Annual evaluation of phytoplankton and its answer to water quality in Amatitlán lake, Guatemala

Se realizó un estudio sobre la composición y abundancia del fitoplancton en el lago de Amatitlán, y el efecto de la calidad de agua sobre su biodiversidad. Para ello, se colectaron muestras de agua en cuatro puntos específicos del lago, en la superficie del agua y a profundidades de 5, 10 y 20 m, de manera mensual durante el 2017. Se midieron parámetros fisicoquímicos in situ como temperatura y pH. Igualmente, se identificaron y contabilizaron cianobacterias y microalgas. El índice de estado trófico (IETP) catalogó al lago como eutrófico e hipertrófico (IETP = 63.80-88.18). Se reportan 34 géneros de fitoplancton distribuidos en 30 familias, 17 órdenes y 10 clases. Los indicadores biológicos, tales como, floraciones algales de Microcystis (38.41%), baja diversidad de diatomeas (Nitzschia, Aulacoseira y Cyclotella), presencia de microalgas Nitzschia y Scenedesmusresistentes a procesos de eutrofización, y alta concentración de coliformes fecales, de hasta 24,000 NMP/100 ml, evidenciaron la baja calidad de agua que se presenta en el lago de Amatitlán. En época seca se encontró más diversidad de microalgas debido a la mayor incidencia de radiación solar, el poco recambio de agua y la acumulación de materia orgánica. Aunque esto varía con los cambios en la concentración de nitrógeno total (NT) y fosforo total (PT), que potencian la proliferación de cianobacterias tóxicas. La biodiversidad del lago fue baja debido al estado hipereutrófico en que se encuentra. Se recomienda poner en funcionamiento plantas de tratamiento de aguas residuales para evitar que esta problemática continúe.

A study was carried out on the composition and abundance of phytoplankton in Amatitlán lake, and the effect of water quality on its biodiversity. For this, water samples were collected at four specific points in the lake, on the water surface and at depths of 5, 10 and 20 m, in a monthly way during 2017. Physicochemical parameters were measured in situ such as temperature and pH. Likewise, cyanobacteria and microalgae were identified and accounted. The trophic state index (IETP) cataloged the lake as eutrophic and hypertrophic (IETP = 63.80-88.18). 34 genera of phytoplankton distributed in 30 families, 17 orders and 10 classes are reported. Biological indicators, such as Microcystis algal blooms (38.41%), low diatom diversity (Nitzschia, Aulacoseira and Cyclotella), presence of Nitzschia and Scenedesmus microalgae resistant to eutrophication processes, and high concentration of fecal coliforms, up to 24,000 NMP/100 ml, evidenced the low quality of water that occurs in lake Amatitlán. In the dry season, more microalgae diversity was found due to the higher incidence of solar radiation, little water change and the accumulation of organic matter. Even though this varies with changes in the concentration of total nitrogen (NT) and total phosphorus (PT), which enhance the proliferation of toxic cyanobacteria. The lake's biodiversity was low due to its hypereutrophic state. We recommend to put this wastewater treatment plants into operation to prevent this problem to continue.

Environmental Soil Phosphorus Threshold under No-Tillage and Swine Manure Application

Abstract Swine manure is applied in agricultural fields as a source of nutrients for plant growth, however, excessive application over the years can promote soil phosphorus (P) accumulation. The objective of this study was to establish the environmental soil P threshold based on the degree of P saturation (DPS), as well, to evaluate the soil P storage capacity. The experiment was carried out in an Oxisol (sandy clay loam texture), under no-tillage and crop rotation. Treatments consisted of four annual doses of liquid swine manure (0, 100, 200, and 300 m3 ha-1 year-1), and three doses of mineral fertilizer (0, 50, and 100% of the crop nutrients requirement), in a randomized block with split-plot design (four replications). Soil P content was analyzed by PMehlich-1, PCaCl2, water-soluble P (WSP) and total P. The application of swine manure and mineral fertilizer increased soil P contents mainly at 0-10 cm depth. The DPS corresponding to the change point was 14.9% at depth 0-10 and 8.6% at depth 0-20 cm with WSP and 18.7% at 0-10 cm and 8.9% at 0-20 cm depth with PCaCl2. The lowest change point value was DPS 8.6% which corresponds to 43 mg kg-1 of PMehlich-1, so, in practical terms, we suggest this value as the environmental soil P threshold. The soil P storage capacity indicated negative values with the higher doses of swine manure and mineral fertilizer which increases the vulnerability of P loss by surface and subsurface hydrological transfer pathway.

System Fertilization: a Viable Practice for Black Oat-soybean Crop

Abstract System fertilization is characterized by partial or total fertilizer application at the predecessor crop; and it can be a viable practice to soybean crop. This study aimed to determine the fertilizer management and fertilizer levels for black oat-soybean cropping system, in high fertility soils and no-tillage system. The field trial was conducted in a bifactorial scheme, consisting of six environments, by combination of locations (Bom Sucesso do Sul - Paraná, Itapejara d'Oeste - Paraná) and fertilization management (all fertilization in black oat; splitting with 50% in black oat and 50% in soybean, all fertilization in soybean), and four fertilizer levels (0, 100, 200 and 300%) defined according to soil analysis and production expected. The evaluated traits were dry mass production, N, P and K nutrient accumulation of straw, dry mass remaining of black oat crop; and plant height, number of pods per plant, thousand grain weight, grain yield for soybean crop. Higher black oat dry mass production was observed at higher fertilization level. The fertilizer anticipation in black oat crop had better performance. Phosphorus and potassium accumulation increased linearly with fertilizer level increase. For N, the highest accumulated value occurred at the 200%, decreasing at the 300% of fertilizer level. The soybean crop had no influence in grain yield considering fertilization management, anticipation or splitting, and fertilizer levels. Thus, the system fertilization can be a viable practice, and favor black oat dry mass production and soybean development.

Does Dairy Liquid Manure Complementary to Mineral Fertilization Increase Grain Yield Due to Changes in Soil Fertility?

Abstract The main destination of manure is the application to croplands near livestock farms as nutrient source to enhance crop production. The aim of this study was to define the dairy liquid manure (DLM) dose, complementary to the mineral fertilizer, for higher crops yield, in rotation black oat-maize-wheat-soybean, and to identify the soil chemical variables improved by the manure that most affect the yield, in long-term. The experiment was conducted from 2006 to 2015, in no-tillage system, at Paraná State, Brazil. The soil was a Latossolo Bruno Distrófico típico, clayey texture. The treatments consisted by doses of DLM (0, 60, 120 and 180 m3 ha-1 year-1), complementary to the mineral fertilizer (applied in the same amount for all DLM doses). Crops yield and soil chemical variables were evaluated at six depths (0-10; 10-20; 20-30; 30-40; 40-50 and 50-60 cm). The DLM application increased the yield of all crops, but not in all harvests. The DLM even applied at soil surface improved the soil chemical variables in deep layers, resulting in high positive correlation between yield and exchange bases, P, Zn and Mn contents, and high negative correlation with Ca/Mg ratio and potential acidity at depth 0-10 cm. The DLM dose, complementary to the mineral fertilization, that provided higher soybean and wheat yield was about 130 m3 ha-1 year-1, while for maize this dose was equal to or greater than 180 m3 ha-1 year-1. This effect was not attributed to a single chemical variable but the improvement of all chemical variables evaluated.

Stocks and Distribution of Soil Carbon, Nitrogen, Phosphorus and Sulfur in an Integrated Crop-Livestock System Treated with Phosphates

Abstract Conservation agriculture practices can contribute to changes in soil nutrient dynamics over time. This experiment evaluated the changes in total stocks and distribution of carbon, nitrogen, phosphorus and sulfur concentrations in soil, during 60 months, in an integrated crop-livestock system (ICLS) due to anticipated fertilization of sources and doses phosphates applied in soil surface. The experiment was conducted over a period of five years, under Typic Dystrudept, using a randomized block design, in an incomplete factorial scheme (3×3+1), with four replications. Treatments consisted of three sources of P [triple superphosphate (TSP), rock phosphate - Arad (RP) and magnesium thermophosphate (MTP)], along with four doses of P (0, 60, 120 and 180 kg ha-1 P2O5 total). Samples of soil were collected in 0-5, 5-10, 10-15, 15-20 and 20-30 cm layers at 24, 36, 48 and 60 months after beggining of experiment where the following chemical attributes were evaluated: (i) total organic carbon (TOC); (ii) total nitrogen Kjeldahl (TNK); (iii) available P by ion exchange resin method (P-IER); and (iv) available S-SO4 2-. The ICLS conditions provided increased total stocks and concentrations of TOC, TNK, P-IER and S-SO4 2- over time. The applications of different phosphates had no influence on soil TOC concentrations during the five years of experimentation. The concentrations of TNK, P-IER and S-SO4 2- showed an increase in different layers of soil, with the application of sources and doses of P. The P fertilization practice that was anticipated can consist of an efficient management of soil fertility, using properly managed conservation systems.

Dinámica del consumo y aporte de nutrientes de fitoplancton, dominado por Microcystis sp. (Cyanophyceae) del lago de Amatitlán / Dynamics of the consumption and nutrient supply of phytoplankton, dominated by Microcystis sp. (Cyanophyceae) of Lake Amatitlán

El impacto antrópico cercano al lago de Amatitlán ha generado niveles altos de eutrofización que conllevan cambios en la dinámica del ecosistema. Uno de ellos es la proliferación de cianobacterias del género Microcystis que pueden llegar a ser perjudiciales para la fauna y flora de lugar e incluso para los seres humanos. Se presenta el caso de cultivo de un consorcio de fitoplancton, tomado directamente del lago y llevado al laboratorio en condiciones controladas, para medir su consumo y aporte de nitrógeno y fósforo, además de los cambios en los factores fisicoquímicos y la biomasa. Se observó la presencia de diatomeas del genero Nitszchia y cianobacterias como Dolichospermum, con una marcada dominancia de Microcystis sp. Se analizó el porcentaje de cambio en la concentración de nutrientes. Los resultados indican que hubo un aumento en las concentraciones de amonio, nitrato y nitrógeno inorgánico disuelto, mientras que disminuyó el nitrógeno total, el fósforo total y los ortofosfatos. Esto indica que hay aporte de nitrógeno inorgánico, consumo de fósforo y nitrógeno orgánico. El fósforo parece ser el nutriente limitante, ya que, al consumirse en un 90 % la biomasa empieza a decrecer.

The anthropic impact near lake Amatitlán has generated high levels of eutrophication that lead to changes in ecosystem dynamics. One of them is the proliferation of cyanobacteria of the genus Microcystis that can be harmful to the fauna and flora of the place and even to humans. The case of cultivation of a phytoplankton consortium, taken directly from the lake and taken to the laboratory under controlled conditions, to measure its consumption and contribution of nitrogen and phosphorus, in addition to changes in physicochemical factors and biomass is presented. The presence of diatoms of the genus Nitszchia and cyanobacteria such as Dolichospermum was detected, with a marked dominance of Microcystis sp. The percentage change in nutrient concentration was analyzed. The results indicated that there was an increase in the amounts of dissolved inorganic ammonium, nitrate and nitrogen, while total nitrogen, total phosphorus and orthophosphates decreased. This indicates that there is contribution of inorganic nitrogen, consumption of phosphorus and organic nitrogen. Phosphorus seems to be the limiting nutrient, since, when consumed by 90 %, biomass begins to decrease.

¿Puede establecerse hoy un valor de fosfatemia como indicador de calidad del tratamiento dialítico? / Can a phosphatemia value be established today as an indicator of the quality of the dialysis treatment?

INTRODUCCIÓN: El trastorno del metabolismo óseo y mineral constituye una grave complicación de la IRC. Respecto al fósforo, las nuevas Guías KDIGO sugieren disminuirla hiperfosfatemia, sin recomendar un valor determinado. Sin embargo, en Argentina se continúa utilizando como indicador de calidad dialítica (IndCalDial) un valor de fósforo igual o inferior a 5 mg.dl. Nuestro objetivo fue evaluar si un valor fijo de fosfatemia es válido como IndCalDial. MATERIAL Y MÉTODOS: Se realizó un estudio multicéntrico, de corte transversal. Se incluyeron pacientes mayores de 18 años, con más de 90 días en hemodiálisis crónica. Se tabularon datos demográficos y de laboratorio. Según el reactivo empleado en la determinación de fósforo, en 4 centros el límite superior de referencia fue 4.5 mg.dl (Grupo F4.5) y en tres 5.6 mg.dl (Grupo F5.6). RESULTADOS: Se incluyeron 334 pacientes. Edad, sexo, porcentaje con FAV, diabéticos, tiempo en diálisis, Kt/V, Hemoglobina y Albúmina, resultaron semejantes a los del Registro Nacional de Diálisis. La mediana de fosfatemia fue 5.2 mg.dl, (rango: 2.3 a 10.6). Los pacientes hiperfosfatémicos fueron más jóvenes y presentaron mejores niveles de Albúmina. De considerarse como IndCalDial: Fósforo menor a 5 mg.dl, 21 pacientes del Grupo F4.5 (n=154) con fosfatemia entre 4.5 y 5.0 mg.dl no recibirían tratamiento, mientras que en el Grupo F5.6 (n=180), 32 pacientes con fosfatemia entre 5.1 y 5.6 mg.dl deberían recibir tratamiento, a pesar de presentar normofosfatemia. CONCLUSIONES: Debería estandarizarse la determinación de fosfatemia, previo a utilizar un valor fijo como IndCalDial

Degradación de hojarasca y aporte de nutrientes del manglar en la Laguna Mecoacán, Golfo de México / Leaf litter degradation and nutrient supply in the mangroves of Mecoacán Lagoon, Gulf of Mexico

Resumen Los manglares son ecosistemas de importante productividad primaria, donde se establece un flujo de energía (nutrientes) con zonas adyacentes y su ambiente acuático, impulsado principalmente por los procesos de degradación. El objetivo del estudio fue estimar el coeficiente de degradación diario (k) de hoja de mangle por medio de bolsas de degradación, en relación con los factores físico químicos del suelo y el aporte de nutrientes (fósforo y nitrógeno) en sedimento del manglar de la Laguna Mecoacán, Golfo de México. El coeficiente de degradación se estimó por medio de bolsas de degradación de hojarasca en seis sitios de monitoreo mensual. Se identificó una rápida degradación durante el primer mes de hasta 51 % en Avicennia germinans (L.) Stearn asociado a procesos de lixiviación por condiciones de inundación. La degradación (k) de Rhizophora mangle L. (k= 0.0052 ± 0.0002) (F= 12.2 p<0.05 n= 216) y Laguncularia racemosa (L.) Gaertn (k= 0.005 ± 0.0003) (F= 3.7 p= 0.02 n= 108) difieren significativamente de A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.02 n= 216). En relación al T50 de R. mangle y L. racemosa presentaron mayor tiempo de degradación (133 y 138 días respectivamente) comparado con A. germinans (74 días). Se registró una correlación significativa entre la materia orgánica y la humedad del suelo con la constante de descomposición de A. germinans (r= 0.65 p< 0.05 y r= 0.55 p< 0.05 respectivamente). El más alto contenido de nitrógeno total se dio en Pajaral (2 683 mg.Kg) y presentó alta correlación con el contenido de materia orgánica (r= 0.9 p= 0.03); en relación al fósforo total, el nivel más alto se presentó en Boca (2 031 mg.Kg) correlacionado de forma negativa con el pH (r= -0.61 p< 0.05). En conclusión, las diferencias en la velocidad de degradación de las hojas de mangle dependen de la especie (composición foliar), tiempo de exposición o inmersión en agua (patrón de inundación) y heterogeneidad del sedimento (i.e., textura, pH, contenido de humedad y densidad aparente).

Abstract Mangroves are ecosystems with a high primary productivity that is mainly driven mainly by degradation processes. Energy (nutrients) flows from mangroves toward adjacent zones and the surrounding aquatic environment. The objective of the present study was to estimate the daily degradation coefficient (k) of mangrove leaves in relation to physical-chemical soil factors and in situ nutrient supply (phosphorus and nitrogen) in Mecoacán Lagoon, Gulf of Mexico. Leaf litter degradation bags were placed at six monthly monitoring sites to evaluate degradation and to calculate the corresponding degradation coefficients. A rapid degradation of up to 51 % was observed for Avicennia germinans (L.) Stearn during the first month in association with leaching resulting from flood conditions. The degradation of Rhizophora mangle (L.) (k= 0.0052±0.0002) (F= 12.2 p< 0.05 n= 216) and Laguncularia racemosa (L.) Gaertn (k= 0.005±0.0003) (F= 3.7 p= 0.2 n= 108), differed significantly from that of A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.2 n= 216) did not present significant differences. To reach T50 degradation, R. mangle and L. racemosa required more time (133 and 138 days, respectively) than A. germinans (74 days). Organic matter and soil humidity were significantly correlated with the decay constant of A. germinans (r= 0.65 p< 0.05 and r= 0.55 p< 0.05, respectively). Total nitrogen content was highest in the Pajaral site (2 683 mg.kg) and was also highly correlated with organic matter content (r= 0.9 p= 0.003). Total phosphorus content was highest in the Boca site (2 031 mg.kg) and was also negatively correlated with pH (r= -0.61 p= 0.004). In conclusion, differences in the rate of mangrove leaf degradation depend on the involved species (leaf composition), time of exposure or immersion in water (flooding patterns) and sediment heterogeneity (i.e., texture, pH, humidity content and bulk density). Rev. Biol. Trop. 66(2): 892-907. Epub 2018 June 01.

Effectiveness of Arbuscular Mycorrhizal Fungal Isolates from the Land Uses of Amazon Region in Symbiosis with Cowpea

ABSTRACT Arbuscular mycorrhizal fungi provide several ecosystem services, including increase in plant growth and nutrition. The occurrence, richness, and structure of arbuscular mycorrhizal fungi communities are influenced by human activities, which may affect the functional benefits of these components of the soil biota. In this study, 13 arbuscular mycorrhizal fungi isolates originating from soils with different land uses in the Alto Solimões-Amazon region were evaluated regarding their effect on growth, nutrition, and cowpea yield in controlled conditions using two soils. Comparisons with reference isolates and a mixture of isolates were also performed. Fungal isolates exhibited a wide variability associated with colonization, sporulation, production of aboveground biomass, nitrogen and phosphorus uptake, and grain yield, indicating high functional diversity within and among fungal species. A generalized effect of isolates in promoting phosphorus uptake, increase in biomass, and cowpea yield was observed in both soils. The isolates of Glomus were the most efficient and are promising isolates for practical inoculation programs. No relationship was found between the origin of fungal isolate (i.e. land use) and their symbiotic performance in cowpea.

Nitrogen and phosphorus flux from the production of Nile tilapia through the application of environmental indicators / Fluxo de nitrogênio e fósforo na produção de tilápia-do-nilo (Oreochromis niloticus) a partir da aplicação de indicadores ambientais

Abstract We aimed in this study utilize environmental indicators as a quantitative method to evaluate and discuss the nitrogen (TN) and phosphorus (TP) flux by a production stage grow-out (termination) of Nile tilapia (Oreochromis niloticus) in fishpond. The TN and TP load, the mass balance, the input of TN and TP via feed and the converted nutrients in fish biomass are the environmental indicators applied in this study. During the production cycle (128 days), the system exported 15,931 g TN and 4,189 g TP that were related to the amount of feed supplied (r Pearson = 0.8825 and r = 0.8523, respectively), corroborated by the feed conversion ratio (1.61:1). The indicators showed that 26% TN and 45% TP were reversed into fish biomass, 62% TN and 40% TP were retained in the fishpond, and 12% TN and 15% TP were exported via effluent. The largest contribution of nutrients generated by the system and exported via effluent was observed in phase III and IV. This result is supported by the feed conversion ratio 2.14 and 2.21:1 obtained at this phase, a fact explained by the amount of feed offered and the fish metabolism. Application of environmental indicators showed to be an efficient tool to quantify flux of TN and TP produced during the grow-out period of Nile tilapia and therefore, guide management practices more sustainable. Concerning the environmental sustainability of the activity the implementation of best management practices such as the better control of the feed amount offered would lead to a smaller loss of TN and TP to the water. Furthermore, the use of better quality feeds would allow greater nutrient assimilation efficiency.

Resumo Nós objetivamos neste estudo, utilizar indicadores ambientais como método quantitativo para avaliar e discutir sobre o fluxo de nitrogênio (TN) e fósforo (TP) na etapa final de crescimento (terminação) de tilápia-do-nilo (Oreochromis niloticus) em viveiro escavado. A carga de TN e TP, o balanço de massa, a entrada de nutrientes via ração e o TN e TP convertido em biomassa de peixe foram os indicadores ambientais utilizados neste estudo. Durante o ciclo produtivo (128 dias), o sistema exportou 15.931 g NT e 4.189 g PT os quais foram relacionadas às quantidades de alimento fornecido (r Pearson = 0,8825 e r = 0,8523, respectivamente), corroborada pela conversão alimentar (1,61:1). Os indicadores evidenciaram que 26% NT e 45% PT foram revertidos em biomassa de peixe, 62% NT e 40% PT ficaram retidos no viveiro e 12% NT e 15% PT foram exportados via efluente. O maior aporte de nutrientes gerado pelo sistema e exportado via efluente foi verificado nas fases III e IV. Este resultado é corroborado pelas taxas de conversão alimentar de 2,14 e 2,21:1 obtida nestas fases, fato explicado pela quantidade de ração ofertada e pelo metabolismo dos peixes. A aplicação dos indicadores ambientais mostrou ser uma ferramenta eficiente para quantificar o fluxo de TN e TP produzidos durante a etapa final de crescimento de tilápia-do-nilo e com isso orientar práticas de manejo mais sustentáveis. Com vistas à sustentabilidade ambiental da atividade, a implantação de boas práticas de manejo tais como o melhor controle da quantidade de alimento ofertado levaria a menor perda de NT e PT para a água. Além disso, o uso de rações de melhor qualidade permitiria maior eficiência de assimilação desses nutrientes.

Combined application of bio-organic phosphate and phosphorus solubilizing bacteria (Bacillus strain MWT 14) improve the performance of bread wheat with low fertilizer input under an arid climate

Abstract This study was aimed to investigate the effect of bio-organic phosphate either alone or in combination with phosphorus solubilizing bacteria strain (Bacillus MWT-14) on the growth and productivity of two wheat cultivars (Galaxy-2013 and Punjab-2011) along with recommended (150-100 NP kg ha−1) and half dose (75-50 NP kg ha−1) of fertilizers. The combined application of bio-organic phosphate and the phosphorous solubilizing bacteria strain at either fertilizer level significantly improved the growth, yield parameters and productivity of both wheat cultivars compared to non-inoculated control treatments. The cultivar Punjab-2011 produced the higher chlorophyll contents, crop growth rate, and the straw yield at half dose of NP fertilizer; while Galaxy-2013, with the combined application of bio-organic phosphate and phosphorous solubilizing bacteria under recommended NP fertilizer dose. Combined over both NP fertilizer levels, the combined use of bio-organic phosphate and phosphorous solubilizing bacteria enhanced the grain yield of cultivar Galaxy-2013 by 54.3% and that of cultivar Punjab-2011 by 83.3%. The combined application of bio-organic phosphate and phosphorous solubilizing bacteria also increased the population of phosphorous solubilizing bacteria, the soil organic matter and phosphorous contents in the soil. In conclusion, the combined application of bio-organic phosphate and phosphorous solubilizing bacteria offers an eco-friendly option to harvest the better wheat yield with low fertilizer input under arid climate.

A disponibilização de fósforo nas águas pelo uso de detergentes em pó: aspectos ambientais e de Saúde Pública / Phosphorus delivered to surface waters resulting from the use of powder detergents: environmental and public health aspects

Resumo Este artigo aborda a interface social e ambiental da presença de fósforo nas águas de abastecimento, dimensionando os impactos ocasionados pelo uso de detergentes fosfatados em pó sobre a qualidade e a disponibilidade dos recursos hídricos, no tocante à ocorrência da eutrofização. Com base em dados a respeito da formulação e consumo dos produtos comercializados no Brasil, relata a evolução do assunto e apresenta o retrato da situação atual. Indica que os detergentes brasileiros possuem, hoje, baixa concentração de fósforo, de forma que representam um reduzido risco de impacto sobre o nível trófico das águas. Pontua, entretanto, a necessidade de ajustar o conteúdo da legislação à prática do mercado e de aprimorar as políticas públicas relacionadas com a educação ambiental. Mediante um processo efetivo de comunicação e educação, será possível conscientizar a população acerca do assunto, contribuindo para a manutenção do controle dessa importante fonte de fósforo no meio ambiente e para o aumento da disponibilidade hídrica, por meio da prevenção dos processos de eutrofização.

Abstract This article addresses the social and environmental aspects related to the presence of phosphorus in surface water bodies, assessing the impacts caused by the utilization of powder detergents on the quality and availability of water resources, with particular respect to the occurrence of eutrophication. Based on data concerning the composition and consumption of the products currently sold in Brazil, the evolution of this phenomenon leading to the current situation is reported. Indications are that Brazilian detergents have a low phosphorus content, thus it is possible to infer that these products offer a small risk of impacting the trophic levels of surface waters. There is, however, a need to adjust the content of legislation to market practices, as well as improve public policies related to environmental education. By means of an intensive process of communication and education, awareness about the issue can be raised, keeping this major source of phosphorus in the environment under control and contributing to the increase in the availability of water, through the prevention of eutrophication processes.

Plankton crustaceans in bays with different trophic status in Llanquihue lake (41° S Chile) / Crustáceos planctónicos crustáceo em baías com estado trófico diferente no lago Llanquihue (41° S Chile)

Abstract The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is to analyze the trophic status and zooplankton relative abundance in different bays of Llanquihue lake. It was found direct associations between chlorophyll a with daphnids percentage, total dissolved nitrogen with reactive soluble phosphorus nitrogen/phosphorus molar radio with cyclopoids percentage, and an inverse relation between daphnids and calanoids percentages. The occurrence of three kinds of microcrustacean assemblages and environmental conditions was evidenced: the first one with high calanoids percentage, low species number and low chlorophyll and nutrients concentration, a second with moderate chlorophyll and nutrients concentration and moderate daphnids percentage; high species number and a third site with high chlorophyll and nutrients concentration, high daphnids percentage and high species number. Daphnids increase under mesotrophic status, agree with similar results observed for southern Argentinean and New Zealand lakes.

Resumo O lago Llanquihue está incluído nos chamados lagos araucana ou Nord Patagônia localizado entre 38-41° S. Estes lagos são caracterizados pela condicao oligo-mesotrofica debido a intervencao humana, com aumento da carga de nutrientes provenientes de industrias y areas urbanas com efeitos sobre as assembleias zooplantonicas sao observadas, com aumento acentuado de dafnideos. O objetivo do presente estudo é analisar o estado trófico a abundancia relative do zooplancton em diferentes compartimentos do lago Llanquihue. Foram encontradas associações diretas entre clorofila a com percentual de dafinídeos, nitrogênio total dissolvido com fósforo solúvel reativo molares razao molar nitrogênio / fósforo com percentual de ciclopóides, e uma relação inversa entre percentuais de dafinídeos e calanóides porcentagens. A ocorrência de três tipos de assembleias de microcrustáceos e as condições ambientais fora: a primeira com alta porcentais de calanóides, baixo número de espécies e baixa clorofila e a nutrientes, uma segunda com concentracoes moderadas de clorofila e nutrientes percentual moderado de daphnideos e alto número de espécies; e uma terceiro local com alta concentração de clorofila e nutrientes, alta abundância dafinídeos e número elevado de espécies. Resultados similares com aumento de dafnideos em condicoes mesotroficas também foram observados para lagos da Argentina e Nova Zelândia do sul.

Effect of phosphorus on arsenic uptake and metabolism in rice cultivars differing in phosphorus use efficiency and response

ABSTRACT A hydroponic experiment was carried out to investigate the effect of phosphorus (P) nutrition on arsenic (As) uptake and translocation within the seedlings of rice cultivars. The experiment occurred in three stages: I 5 days of acclimatization (nutritive solution); II 10 days under P (0.0 and 0.09 mM) and As (0.0 and 100 mM) treatments; III 5 days under recovery. The As exposure had significant effect reducing dry weights of shoots or roots, resulted in elevated concentrations of As in shoot tissues. BR-IRGA 409 showed the highest susceptibility to As in biomass production and root system parameters regardless the P level. This cultivar showed contrasting responses of As translocation to shoot tissue dependent on P levels, with the highest As concentration under low P and lowest under normal P levels. P nutrition was most striking on plants recovery for all cultivars under As exposure. Clearer separation of cultivars for phosphorus use efficiency (PUE) occurred at lower shoot P contents, that was, at higher levels of P deficiency stress. IRGA 424 showed higher PUE as compared to the others cultivars. Our results go some way to understanding the role of P nutrition in controlling the effects of As in rice shoots.