Spatio-temporal distribution of temperature, salinity and suspended sediment on the deltaic front of the Magdalena River: Influence on nutrient concentration and primary productivity

The characteristics of estuaries depend mainly on the magnitude and variability of river discharge and tidal forcing (Kjerfve, 1994). Estuaries present strong temporal and spatial gradients with respect to their physical, chemical and biological properties, as a result of changes in fluvial contributions (Nogueira et al., 1997). Therefore, biogeochemical processes are extremely complex (Fourqurean et al., 1993; Fernández-Nóvoa et al., 2015). Temperature and salinity are the most relevant features of coastal marine ecosystem dynamics (Urquhart et al., 2013), as variations in these parameters can influence the movement of water masses, water column stratification caused by density differences, transport of sediments, and mixing conditions (Bianchi, 2007; Geyer, 2010; Obeso-Nieblas et al., 2012; Osadchiev et al., 2017). Also, temperature and salinity may play roles in nutrient distributions and concentrations (Windom et al., 2006), and biogeochemical processes and ecological productivity, through alterations in biochemical reactions that regulate the enzymatic processes of respiration and photosynthesis (Xia and Jiang, 2015; Quamrul et al., 2016). The physical dynamics of estuaries/deltas of the micro-tidal domain, which are highly stratified and turbid, have been little studied. Therefore, we lack detailed knowledge regarding relationships among spatio-temporal variations in salinity and temperature, the extent and structure of convergence fronts and the mixed layer, nutrient distribution and primary productivity in this type of estuary

Efecto de la reproducción artificial y de la variabilidad genética en la producción DE LARVAS DE bocachico (Prochilodus magdalenae) para repoblación.

Prochilodus magdalenae es un pez endémico de Colombia de gran importancia económica. Actualmente se encuentra amenazado, siendo prioridad la implementación de estrategias que permitan mejorar sus condiciones naturales para evitar su extinción. Una estrategia es la implementación de programas de repoblación; sin embargo, estos no son basados en criterios científicos, ya que las granjas piscícolas no tienen en cuenta las herramientas genéticas, lo que favorece el cruzamiento de reproductores emparentados y esto trae como consecuencia la reducción de la variabilidad genética. Además, no existe un método estandarizado de reproducción artificial para la producción de larvas. El objetivo de la presente investigación fue evaluar el efecto del tipo de reproducción artificial (húmedo y seco) y la variabilidad genética individual de los reproductores en la producción de larvas de bocachico con fines de repoblación. Los indicadores de producción fueron la fecundidad, tasa de fertilización, tasa de eclosión y supervivencia de las larvas. Los mejores resultados se observaron con el método húmedo, seleccionándolo para evaluar el efecto genético. Para esto se realizaron tres tipos de cruces variando la heterocigosidad individual de los reproductores previamente caracterizados (HoHo0.6). Como resultado se observó que la fecundidad, tasa de fertilización, tasa de eclosión y supervivencia de las larvas son parámetros condicionados por la calidad genética del reproductor (p<0.05). De la misma manera, la calidad genética de las larvas es dependiente del nivel de heterocigosidad individual de los reproductores seleccionados para los cruces (p<0.05), registrando una pérdida de heterocigosidad (variabilidad genética) de reproductores (Ho=0.190, 0.444, 0.730) a larvas (Ho=0.198, 0.203, 0.392) a medida que se avanza en la obtención de progenies, es decir, a pesar de que los reproductores presentan una mayor variabilidad genética, las progenies expresaron una baja heterocigosidad observada

Physicochemical and functional characterization of trupillo flour (Prosopis juliflora (Sw.) DC) and its inclusion in a food matrix

Introduction: The high protein content has made legumes a raw material of interest in the formulation of different agro-industrial products; the trupillo (Prosopis juliflora) tree is an easily accessible, multipurpose, wild legume that can be used in all its composition, has a high protein value and little commercial level, which is currently being wasted as it is mistakenly considered a weed and that It could be seen as a new alternative that helps in the potentialization of the food sector. Objective: This research aims to functionally characterize trupillo flour (Prosopis juliflora), obtained from leaves and seeds, to include it in a food matrix as a protein extender. Methodology: The experimental design for this research required three phases, i) obtaining, bromatological and functional characterization of leaf flour and trupillo seeds, ii) standardization of formulations for artisan sausages using trupillo flour as a protein source, and iii) bromatological and sensory characterization of the processed sausages. Results: It was found that the flours obtained preserved the characteristic odor and color of each raw material. Particularly, the seed flour presented bromatologically and functionally better protein contents (27.7%), ash (8.04%), swelling capacity (16.7 ml water / g sample), water absorption (7.89 g water / g sample) and water retention capacity (27.9 g water/g sample), for which it was selected to be included in the sausages. In the three formulations made (C, CT and T), there were variations in the color and texture of the sausages, with Formulation T standing out for presenting higher protein content (13.7%). However, consumers preferred Formulation C. Conclusions: These results allow to propose the inclusion of sausage with trupillo flour in the human diet as an alternative to traditional products.Introduction: The high protein content has made legumes a raw material of interest in the formulation of different agro-industrial products; the trupillo (Prosopis juliflora) tree is an easily accessible, multipurpose, wild legume that can be used in all its composition, has a high protein value and little commercial level, which is currently being wasted as it is mistakenly considered a weed and that It could be seen as a new alternative that helps in the potentialization of the food sector. Objective: This research aims to functionally characterize trupillo flour (Prosopis juliflora), obtained from leaves and seeds, to include it in a food matrix as a protein extender. Methodology: The experimental design for this research required three phases, i) obtaining, bromatological and functional characterization of leaf flour and trupillo seeds, ii) standardization of formulations for artisan sausages using trupillo flour as a protein source, and iii) bromatological and sensory characterization of the processed sausages. Results: It was found that the flours obtained preserved the characteristic odor and color of each raw material. Particularly, the seed flour presented bromatologically and functionally better protein contents (27.7%), ash (8.04%), swelling capacity (16.7 ml water / g sample), water absorption (7.89 g water / g sample) and water retention capacity (27.9 g water/g sample), for which it was selected to be included in the sausages. In the three formulations made (C, CT and T), there were variations in the color and texture of the sausages, with Formulation T standing out for presenting higher protein content (13.7%). However, consumers preferred Formulation C. Conclusions: These results allow to propose the inclusion of sausage with trupillo flour in the human diet as an alternative to traditional products.&nbsp

Caracterización de una cepa nativa de saccharomyces cerevisiae para obtener un biopreparado con perfil probiótico

Generation of organic wastes is a worldwide environmental issue, although, if properly handled they may be a valuable source of animal nutrients. The objective was to determine the performance of a wild strain Saccharomyces cerevisiae in a biopreparation from ruminal content enriched with peels of fruits. Probiotic properties of the wild strain such as tolerance to bile salts, pH changes, changes in temperature, high concentrations of sodium chloride; additional to antagonism testing and gas production from glucose were verified in vitro. Microbial growth was evaluated in a medium prepared from clarified ruminal content 40 % v/v, enriched with peel wastes from papaya, pineapple and banana at 25, 50, and 75 % w/w concentrations. Results showed that wild strain had a higher growth in the medium obtained with 50 % w/v fruit wastes. Growth of the strain in this medium disclosed the highest biomass production at 40 hours (2.28x108 cfu·mL-1 ). The viability of the strain showed no important decrease during two months in the log scale of the inoculum. It is concluded that ruminal content enriched with fruit peels provides necessary nutrients for growth of the wild strain S. cerevisiae with probiotic characteristics and the biopreparation represents a supplement which may be useful not only at nutritional level but also to decrease environmental impact caused by these organic wastes.La generación de desechos orgánicos es un problema medioambiental mundial, aunque, si se maneja adecuadamente, puede ser una valiosa fuente de nutrientes para animales. El objetivo fue determinar el rendimiento de una cepa silvestre de Saccharomyces cerevisiae en un biopreparado a partir de contenido ruminal enriquecido con cáscaras de frutas. Se verificaron in vitro las propiedades probióticas de la cepa como tolerancia a sales biliares, cambios de pH, cambios de temperatura y altas concentraciones de cloruro de sodio, así como de pruebas de antagonismo y producción de gas a partir de la glucosa. Se evaluó el crecimiento microbiano en el medio elaborado a partir del contenido ruminal al 40% v/v, enriquecido con desechos de cáscaras de papaya, piña y banano en concentraciones de 25, 50 y 75 %. El mayor crecimiento se produjo en el medio con 50 % de desechos de frutas y la cepa reveló la mayor producción de biomasa a las 40 horas (2,28x108 ufc·mL-1 ). Su viabilidad no presentó disminución importante en la escala logarítmica del inóculo durante dos meses. Se concluye que el contenido ruminal enriquecido con cáscaras de frutas al 50 %, proporciona los nutrientes necesarios para el crecimiento de S. cerevisiae con características probióticas, y el biopreparado representa un suplemento que no solo puede ser benéfico a nivel nutricional, sino que también disminuiría el impacto ambiental ocasionado por estos desechos orgánicos

Suspended sediment load in northwestern South America (Colombia): A new view on variability and fluxes into the Caribbean Sea

Monthly averaged suspended sediment load data from seven rivers in northern Colombia (Caribbean alluvial plain) draining into the Caribbean Sea were analyzed to quantify magnitudes, estimate long-term trends, and evaluate variability patterns of suspended sediment load. Collectively these rivers deliver an average of around 146.3 × 106 t yr−1 of suspended sediments to the Colombian Caribbean coast. The largest sediment supply is provided by the Magdalena River, with a mean suspended sediment load of 142.6 × 106 t yr−1, or 38% of the total fluvial discharge estimated for the whole Caribbean littoral zone. Between 2000 and 2010, the annual suspended sediment load of these rivers increased by as much as 36%. Wavelet spectral analyses identified periods of intense variability between 1987-1990 and 1994–2002, where major oscillation processes appeared simultaneously. The semi-annual, annual and quasi-decadal bands are the main factors controlling suspended sediment load variability in fluvial systems, whereas the quasi-biennial and interannual bands constitute second-order sources of variability. The climatic and oceanographic drivers of the oscillations identified through wavelet spectral analyses define a signal of medium-long-term variability for the suspended sediment load, while the physiographic and environmental characteristics of the basins determine their ability to magnify, attenuate or modify this signal

Efeito da pressão de vácuo na carne de peixe Yamú (Brycon amazonicus) durante o armazenamento refrigerado

This study aimed to assess the cryoprotectant effect of vacuum packaging (35 and 45 kPa) on cold preserved (0 °C and -18 °C) fillets of Yamú (Brycon amazonicus), during 5 days of storage. We analyzed the physicochemical and microbiological changes in the fillets during storage time. Yamú’s water holding capacity, nitrogenated bases content (TVB-N) and texture (N) were affected (p ≤ 0.05) by time and temperature. Bacterial colonies in fillets did not represent a risk for human health after five days of storage. In conclusion, vacuum packing positively (p ≤ 0.05) reduces the effect of cold over Yamú fillets properties.O objetivo deste trabalho foi avaliar o efeito crioprotetor de embalagens a vácuo (35 e 45 kPa) em filés de Yamú (Brycon amazonicus) conservados a frio (0 °C e -18 °C), durante cinco dias de armazenamento. As alterações físico-químicas e microbiológicas foram analisadas nos filés durante o armazenamento. A capacidade de retenção de água, o teor de base nitrogenada (BTV-N) e a textura (N) foram influenciados (p ≤ 0,05) pelo tempo e pela temperatura. Colônias bacterianas em filés não representaram risco à saúde humana após cinco dias de armazenamento. O uso de embalagem a vácuo apresentou efeito significativo positivo (p ≤ 0,05), reduzindo o efeito do frio sobre as propriedades dos filés

Modelamiento Matemático de las isotermas de sorción de tres variedades de yuca industrial

A completely randomized design was used to model the sorption isotherms of three types of industrial cassava. The samples consisted of slices (3.6 cm ×0.6 cm ×0.5 cm) of three varieties of cassava: Corpoica Tai, Corpoica Gynes and Corpoica Veronica. Temperature was set at 20 °C, 30 °C and 45 °C. All experiments were performed in triplicate. Data were obtained through an experimental dynamic method to calculate desorption and adsorption isotherms. Results were analyzed for each temperature, and isotherms were calculated for each variety. Isotherms were statistically equal for all temperatures at a 95 % confidence level. The isotherms were adjusted based on mathematical models (GAB, BET, Smith, Oswin, Henderson, and Peleg). The GAB model was considered the most appropriate for data correlationCon el fin de modelar las isoterma de sorción de láminas (3.6 cm ×0.6 cm ×0.5 cm) de tres variedades de yuca industrial, se empleó un diseño completamente al azar en arreglo factorial con dos factores: temperatura (20 °C, 30 °C y 45 ºC) y variedad (Corpoica Tai, Corpoica Gynes y Corpoica Veronica), con tres repeticiones. Para la obtención de los datos se empleó la técnica experimental del método dinámico para determinar las isotermas de desorción y adsorción. Los datos obtenidos fueron analizados para cada temperatura, determinándose las isotermas para las variedades estudiadas, las cuales fueron estadísticamente iguales entre sí para las tres temperaturas utilizadas aun nivel de confianza del 95%. Las isotermas fueron ajustadas a los modelos matemáticos de Gab, Bet, Smith, Oswin, Henderson y el modelo de Peleg y se determinó que el modelo de GAB es el más adecuado para correlacionar los datos obtenidos

Variability of nitrogen mineralization from organic matter in agricultural soils in the north of Colombia

Variation of Nitrogen mineralization (Nm) and its relationship to physicochemical factors in soils of an irrigation district in the North of Colombia was evaluated. Physicochemical parameters were measured in topsoil (0–30 cm) samples taken from 22 points in agricultural lands (10 in the dry season, 12 in the wet season). Nm was estimated from organic matter (OM) content. Soil parameters in the study area are suitable for crop development, although they present variations between the dry and wet season, where the soil pH varies of slightly acidic to neutral and the OM content decreases. Additionally, in the dry season there was a positive correlation with pH, OM and C/N ratio and, during wet season between OM, sand, clay and bulk density. In both seasons, a negative correlation between silt and Nm was common. Environmental and soil conditions in the study area are favourable for Nm because during the dry season the accumulation of OM is favoured. Understanding how physicochemical factors influence Nm is essential for agricultural activities and the development of sustainable ecosystem services

Variabilidad genética en la producción de larvas de Prochilodus magdalenae usadas en programas de repoblamiento en el río Magdalena, Colombia

The objective of this research was to evaluate the effect of individual genetic variability of spawners in the procurement (production and genetic quality) of Prochilodus magdalenae larvae, used in the repopulation programs in the Magdalena river (Colombia). The spawners system was used based on the genetic criteria of the Centro Acuícola y Agroindustrial de Gaira (SENA Magdalena, Colombia), forming groups with different levels of individual heterozygosity (Ho&lt;=0.3; 0.3&gt;Ho&lt;=0.6 y Ho&gt;0.6). The hormonal induction was done with Pituitary Carp Extract (PCE) using a dosage of 6.6 mg/Kg. The production parameters in the different levels of heterozygosity were measured, such as weight, fertility, fertilization rate, hatching and survival rate. The larvae obtained were fixed in alcohol at 96% for the genetic analyses performed through the use of seven loci micro-satellites. There were significant differences between the individual heterozygosity intervals both in the production parameters and in the genetic quality of the obtained progenies (p &lt; 0.05). A decrease was detected in the heterozygosity observed in the obtained progenies (Ho=0.198, 0.203, 0.392) compared to the heterozygosity of the spawners (Ho=0.190, 0.444, 0.730) for the three intervals of heterozygosity evaluated. The parameters of weight production, fertilization rate and survival, as well as the genetic quality in terms of Ho and Fis of the obtained progenies, are positively related with the genetic variability of the spawners. It is therefore advised that in order to implementbreeding programs, spawners with individual heterozygosity values above 0.6 are used for the production of larvae destined to the repopulation of natural communities of P. magdalenae.El objetivo de esta investigación consistió en evaluar el efecto de la variabilidad genética individual de los reproductores en la obtención (producción y calidad genética) de larvas de bocachico (Prochilodus magdalenae) usadas en los programas de repoblamiento en el río Magdalena (Colombia). Se utilizó el sistema de reproductores con criterio genético del Centro Acuícola y Agroindustrial de Gaira (SENA Magdalena, Colombia), conformando grupos con diferentes niveles de heterocigosidad individual (Ho&lt;=0.3; 0.3&gt;Ho&lt;=0.6 y Ho&gt;0.6), la inducción hormonal fue realizada con Extracto Pituitario de Carpa (EPC) a una dosis de 6.6 mg/Kg. Se midieron parámetros de producción en los diferentes niveles de heterocigosidad tales como peso, fecundidad, tasa de fertilización, tasa de eclosión y supervivencia. Las larvas obtenidas fueron fijadas en alcohol al 96% para los análisis genéticos a través del uso de siete loci microsatélites. Hubo diferencias significativas entre los intervalos de heterocigosidad individual tanto en los parámetros de producción como en la calidad genética de las progenies obtenidas (p &lt; 0.05). Se observó una disminución de la heterocigosidad observada en las progenies obtenidas (Ho=0.198, 0.203, 0.392) en comparación con la heterocigosidad de los reproductores (Ho=0.190, 0.444, 0.730) para los tres intervalos de heterocigosidad evaluados. Los parámetros de producción de peso, tasa de fertilización y supervivencia; así como la calidad genética en términos de Ho y Fis de las progenies obtenidas, están relacionados positivamente con la variabilidad genética de los reproductores, por lo que se recomienda que para implementar programas de crianza, se utilicen reproductores con valores de heterocigosidad individual superiores a 0.6 para la producción de larvas destinadas al repoblamiento de poblaciones naturales de P. magdalenae

Relationship between soil physicochemical characteristics and nitrogen-fixing bacteria in agricultural soils of the Atlántico department, Colombia

Microbial richness of agricultural soils is an indicator of its health and fertility with a significant impact on crop yields. Present study analyzed the relationship between nitrogen-fixing bacteria and physicochemical characteristics of agricultural soils in the southern department of Atlántico, Colombia. Soil samples were collected from 10 sites of Repelón irrigation district, for physicochemical analysis (pH, organic matter, texture, moisture and available phosphorus) and isolation of nitrogen-fixing bacterial’ strains using nitrogen-free culture media. Results demostrated the higher previlance of nitrogen–fixing bacteria in northern zone and central zone of the Repelón irrigation district (1.63 × 108 CFU g-1 for strain-1, 5.2 × 107 CFU g-1 for strain-2 and 4.5 × 107 CFU g-1 for strain-3). On the other hand, the physicochemical characteristics of soil show the adequacy to sustain nitrogen-fixing bacteria. The findings of the present research may serve as a baseline to identify soil micorganisms and defining strategies for sustainable management of agricultural soils in the region because these are integral component in ecosystem for nutrient recycling. © 2017, Soil Science Society of Pakista