RESUMEN La hidroponía es la tecnología de la agricultura sin suelo, en la que las plantas crecen en un medio acuático. Mientras que la acuaponía es un sistema de producción de alimentos en rápido crecimiento que integra la hidroponía con la acuicultura (cultivo de peces). El objetivo de este estudio fue comparar la producción de acelga (Beta vulgaris var. Cicla L.) mediante un sistema hidropónico típico y un sistema acuapónico de producción de tilapia (Oreochromis niloticus) en invernadero. Se utilizaron seis sistemas de recirculación independientes para comprobar la producción por triplicado. Un análisis de regresión lineal simple indicó que la tasa de producción de hojas difirió de forma significativa entre sistemas (p < 0.05), ya que en el hidropónico se obtuvieron 3.46 hojas semana-1, mientras que en el acuapónico fue de 1.53 hojas semana-1. La biomasa vegetal aumentó 53.91 g semana-1 en el tratamiento hidropónico y 38.24 g semana-1 en el acuapónico, aunque dichas tasas de producción no difirieron significativamente (p>0.05). No se detectaron diferencias significativas en las concentraciones de amonio (NH4 +), nitrito (NO2 -), y fosfato (PO4 +) en ambos tratamientos; pero se encontraron diferencias significativas para nitratos (NO3 -) entre sistemas (p < 0.05). La producción de acelgas en el sistema hidropónico fue mayor que en el sistema acuapónico en cuanto al número de hojas y la biomasa.

ABSTRACT Hydroponics is the technology of soil-less agriculture, in which plants are grown in an aquatic environment. While aquaponics is a fast-growing food production system that integrates hydroponics with aquaculture (fish farming). The objective of this study was to compare the production of chard (Beta vulgaris var. cicla L.) using a typical hydroponic system and an aquaponic system for tilapia (Oreochromis niloticus) production in a greenhouse. Six independent recirculation systems were used to test production by triplicate. Simple linear regression analysis showed that leaf production rate differed significantly between systems (p < 0.05), where the hydroponic trial produced 3.46 leaves week-1 and the aquaponic trial 1.53 leaves week-1. Plant biomass increased by 53.91 g week-1 in the hydroponic and 38.24 g week-1 in the aquaponic treatment, although these production rates did not differ significantly (p > 0.05). No significant differences were detected in the concentrations of ammonium (NH4 +), nitrite (NO2 -), and phosphate (PO4 +) between the treatments; however, significant differences were found for nitrate (NO3 -) between the systems (p < 0.05). Chard production in the hydroponic system was higher than in the aquaponic system in terms of leaf number and biomass.

Abstract Introduction: The aquaculture industry is constantly growing, registering a global production of almost 88 million tonnes by 2020. This industry brings environmental problems if its effluents are not properly treated. In 2020, the first technology-based company of CONICET was established in Argentine Patagonia whose purpose is the aquaculture production of the green sea urchin, Arbacia dufresnii to develop a range of nutraceutical products. Its cultivation system entails a commitment to sustainability since its creation, and yet it generates effluents with high levels of nitrates and phosphates. Objective: Given this scenario, and valuing bioremediation as a water treatment tool, the use of marine microalgae as phytoremediating agents of aquaculture effluent is proposed in this work. Methods: The microalgae Chaetoceros gracilis, Navicula sp., Tetraselmis suecica, Rhodomona salina, Nanochloropsis galvana and Cylindrotheca closterium were use; which are used as food for sea urchins larvae in the production process. An experiment was designed that compares the microalgal growth and the removal capacity of nutrients in the effluent in contrast to the artificial culture medium currently used in the production cycle. Results: It is possible to remedy the aquaculture industry’s effluent by employing the selected microalgae, with a percentage of removal efficiency of 100 % of the nitrate and an average removal efficiency percentage of 50 % for all the microalgae tested. Likewise, significantly higher microalgal biomass values were obtained when the culture was carried out in the effluent the culture in the artificial environment. Conclusions: The advances in research provided in this work show that it is possible to take advantage of a discard to cultivate microalgae, even improving microalgal productivity for use as food, reducing the costs involved in the microalgal production sector by changing the use of the type of current culture medium (F/2) for that from a current discard. These advances, if scaled and validated, can improve industry sustainability standards within the framework of a circular economy.

Resumen Introducción: La industria acuícola está en constante crecimiento, registrando una producción mundial de casi 88 millones de toneladas para el año 2020. Esta industria trae consigo problemas ambientales si sus efluentes no son debidamente tratados. En el 2020, se constituyó la primera empresa de base tecnológica del CONICET en la Patagonia Argentina cuyo propósito es la producción acuícola del erizo verde de mar, Arbacia dufresnii con la finalidad de elaborar una gama de productos nutracéuticos. Su sistema de cultivo conlleva un compromiso de sustentabilidad desde su creación, y sin embargo genera efluentes con niveles altos de nitratos y fosfatos. Objetivo: Ante este escenario, y valorizando la biorremediación como herramienta de tratamiento de aguas, se propone en este trabajo la utilización de las microalgas marinas como agentes fitorremediadores del efluente acuícola. Métodos: Se utilizaron las microalgas Chaetoceros gracilis, Navicula sp., Tetraselmis suecica., Rhodomona salina., Nanochloropsis galvana y Cylindrotheca closterium, las cuales son usadas como alimento de las larvas del erizo en el proceso productivo. Se diseñó un experimento que compara el crecimiento microalgal y la capacidad de remoción de los nutrientes en el efluente en contraste con el medio de cultivo artificial actualmente usado en el ciclo productivo. Resultados: Es posible remediar el efluente de la industria acuícola mediante las microalgas seleccionadas, con porcentaje de eficacia de remoción del 100 % del nitrato y un porcentaje de eficacia de remoción promedio de 50 % para todas las microalgas testeadas. Asimismo, se obtuvieron valores de biomasa microalgal significativamente mayores cuando el cultivo fue realizado en el efluente respecto del cultivo en el medio artificial. Conclusiones: Los avances en investigación proporcionados en este trabajo ponen de manifiesto que es posible el aprovechamiento de un descarte para cultivar las microalgas, incluso mejorando la productividad microalgal para su uso como alimento, disminuyendo los costos involucrados en el sector de producción microalgal cambiando el uso del tipo de medio de cultivo actual (F/2) por el proveniente de un descarte. Estos avances si son escalados y validados, pueden mejorar los estándares de sustentabilidad de la industria en el marco de una economía circular.

ABSTRACT Sodic soils pose a challenge for the agricultural production due to their lack of nutrients, poor structure, low organic matter content, and susceptibility to erosion (water and wind). Their recovery is carried out by soil washing and applying calcium salts, which are sometimes unprofitable processes. A low-cost and environmentally friendly alternative to remedy adverse soil conditions is bioremediation using microorganisms or organic amendments. For this reason, this study intended to evaluate the effects of the addition of dry microalgal biomass on sodic soils and suggest its use as an organic amendment. The effect of the microalgal biomass was studied through the mineralization dynamics of carbon and nitrogen sources in short-term experiments. All experiments were performed at laboratory scale. Microalgal biomass was obtained from a consortium grown in dairy wastewater and subsequently dried and pulverized. Four different treatments of dry microalgal biomass were applied to 50 g of sodic soil, and high microbial activity was observed in the soil (obtaining a production of 240 mg C-CO2/kg dry soil), along with the production of nitrates (presenting values 33.8-1.45 mg N-NO3 +/kg dry soil) via the release of ammonia (obtaining 5.46 mg N-NH3 +/kg dry soil), and mineralization of organic N into ammonium (producing 1071.92 mg N-NH4 +/kg dry soil). The microalgal biomass as an organic amendment showed to be prone to mineralization and release of carbon and nitrogen sources, improving the microbial activity in a soil with sodicity problems.obial activity, dairy wastewater.

RESUMEN Los suelos sódicos representan un reto para la industria agrícola debido a su falta de nutrientes, mala estructura, poca materia orgánica y susceptibilidad a sufrir erosión hídrica y eólica. Su recuperación se realiza mediante lavados y aplicación de sales de calcio, los cuales a veces resultan ser procesos poco rentables. Una alternativa de tratamiento de bajo costo y amigable con el ambiente es la aplicación de microorganismos y enmiendas orgánicas con la finalidad de mejorar las condiciones adversas del suelo. Por tal motivo, este estudio se propuso evaluar los efectos de la adición de biomasa microalgal seca en suelos sódicos y sugerir su uso como enmienda orgánica. Se estudió el efecto de la biomasa microalgal mediante dinámicas de mineralización de fuentes de carbono y nitrógeno en experimentos a corto plazo. Todos los experimentos se realizaron a escala de laboratorio. Microalgal biomass was obtained from a consortium grown in dairy wastewater and subsequently dried and pulverized. En frascos de vidrio con 50 g de suelo sódico, se aplicaron cuatro concentraciones distintas de biomasa microalgal seca, observándose en el suelo una actividad microbiana alta (producción de 240 mg C-CO2/kg suelo seco), mineralización de nitratos (de 33.8 a 1.45 mg N-NO3 − /kg suelo seco) vía liberación de amoniaco (5.46 mg N-NH3 +/kg suelo seco) y mineralización del nitrógeno orgánico a amonio (1071.92 mg N-NH4 +/kg suelo seco). La biomasa microalgal resultó ser una enmienda orgánica susceptible a la mineralización y con liberación de fuentes de carbono y nitrógeno, mejorando la actividad microbiana en el suelo con problemas de sodicidad.

RESUMO: A soja-hortaliça apresenta alto valor nutritivo e oferece benefícios funcionais para o organismo humano. No entanto, seu uso na culinária ainda é limitado, principalmente devido à falta de conhecimento sobre suas propriedades. Além disso, a disponibilidade de cultivares para consumo humano é reduzida. Portanto, este estudo foi realizado em Botucatu, Brasil, com o objetivo de verificar o potencial de cultivares de soja-grão (SG) e soja de duplo propósito (SDP) para consumo como soja-hortaliça (SH). Assim, vagens foram colhidas no estádio R6, foram avaliados quanto os teores de compostos bioativos (compostos fenólicos totais, flavonoides, atividade antioxidante e proteínas) e de antinutricionais (nitratos, oxalato, alcaloides e taninos). A cultivares apresentaram mesmo teor de proteína, não diferindo estatisticamente entre si, bem como para nitrato e oxalato. O conteúdo de compostos fenólicos e atividade antioxidante total da cultivar SG, diferiu estatisticamente do conteúdo das cultivares SPD e SH, respectivamente. De acordo com os resultados, a cultivar SG, com colheita das vagens em R6, apresentou qualidade nutracêutica e teores de compostos antinutricionais compatível com as duas cultivares propostas para soja vegetal. RESUMO sojahortaliça hortaliça entanto limitado propriedades disso reduzida Portanto Botucatu Brasil sojagrão grão SG (SG SDP (SDP SH. SH . (SH) Assim R6 R totais flavonoides proteínas nitratos, nitratos (nitratos oxalato taninos. taninos taninos) proteína si respectivamente resultados vegetal (SH

ABSTRACT: Vegetable soybean has high nutritional value and offers functional benefits to human body. However, its use in cooking is still limited, mainly due to the lack of knowledge about its properties. In addition, the availability of cultivars for human consumption is reduced. Therefore, this study was conducted in Botucatu, Brazil, to assess the potential of grain soybean (GS) and dual-purpose soybean (DPS) cultivars for consumption as vegetable soybean (VS). Pods were harvested at R6 stage, and the contents of bioactive compounds (total phenolic compounds, flavonoids, antioxidant activity and proteins) and antinutritional components (nitrates, oxalate, alkaloids and tannins) were evaluated. The cultivars showed the same protein content, not differing statistically from each other, as well as for nitrate and oxalate. The content of phenolic compounds and total antioxidant activity of the SG cultivar differed statistically from the content of the DPS and VS cultivars, respectively. According to the results, the GS cultivar, with pods harvested at R6 stage, showed nutraceutical quality and contents of antinutritional compounds similar to those of the two cultivars proposed for the vegetable soybean. ABSTRACT body However limited properties addition reduced Therefore Botucatu Brazil (GS dualpurpose dual purpose (DPS VS. . (VS) R stage flavonoids proteins nitrates, nitrates (nitrates oxalate tannins evaluated other respectively results (VS

Summary: The continuous use of excessive nitrogenous fertilizers generates environmental risks by increasing nitrate accumulation, volatilization and leaching in soil, which causes losses and low efficiencies in the use of nitrogen (N). The objective of the present study is to evaluate the application of nitrogenous nanocomposites (NCN) as a slow-release fertilizer (SRF) in soil and its effect on growth of the lettuce crop. The NCN was prepared by sorption of a cationic surfactant on a bentonite clay. The study was performed in soil columns; the evaluated treatments were ratios of NCN and conventional fertilizer (FC) 25/0, 50/0, 75/0 and 100/0, 0/100, 25/75, 50/50 and 75/25. The variables evaluated were: fresh weight, dry biomass, leaf area, electrical conductivity, NO3- concentration in leachate and leaf, soil plant analysis development (SPAD) and normalized difference vegetation index (NDVI) units, as well as NCN release in deionized water. The results obtained indicate that the NCN treatments equaled the control after 40 days except for the 25/0 treatment that reduced the fresh weight variables by 20% and leaf area by 18% with respect to the 0/100 control. The SPAD and NVDI values did not have significant differences between treatments. The NCN/FC 0/100, 50/50 and 75/25 ratios increased nitrate concentration in leaves by 19%. The 100/0 treatment increased total dry biomass with 48%, 87% root volume and 73% root dry biomass. The results of the release in deionized water confirmed that NCN gradually releases nitrates and in higher amounts than those calculated. Finally, to conclude the nanocomposite material has the potential to be used as a slow-release fertilizer when growth increases. Therefore, nanocomposites could be an alternative to reduce the use of conventional fertilizers and nitrogen losses in soil.

Resumen: El uso continuo de fertilizantes nitrogenados en exceso genera riesgos ambientales al aumentar en el suelo la acumulación, volatilización y lixiviación de nitratos, que provocan pérdidas y baja eficiencia en la utilización de N. En este estudio, el objetivo fue evaluar la aplicación de nanocompuestos nitrogenados (NCN) como fertilizante de liberación lenta en el suelo y su efecto en el crecimiento del cultivo de lechuga. El NCN se preparó por la sorción de un surfactante catiónico en una arcilla de bentonita. El estudio se realizó en columnas de suelo, los tratamientos evaluados fueron relaciones de NCN y fertilizante convencional (FC) 25/0, 50/0, 75/0 y 100/0, 0/100, 25/75, 50/50 y 75/25. Las variables evaluadas fueron: peso fresco, biomasa seca, área foliar, conductividad eléctrica, concentración de NO3 - en lixiviado y hoja, unidades SPAD y NDVI, además de la liberación del NCN en agua desionizada. Los resultados obtenidos indican que después de 40 días los tratamientos con NCN igualaron al control excepto el tratamiento 25/0 que redujo las variables peso fresco 20% y el área foliar 18% con respecto al control 0/100. Los valores de SPAD y NVDI no tuvieron diferencias significativas entre tratamientos. Las relaciones NCN/FC 0/100, 50/50 y 75/25 aumentaron 19% la concentración de nitratos en hojas. El tratamiento 100/0 aumentó biomasa seca total con 48%, 87% el volumen radical y 73% la biomasa seca de raíz. Los resultados de la liberación en agua desionizada confirmaron que el NCN libera gradualmente nitratos y en mayor cantidad que lo calculado. Finalmente, se concluye que el material nanocompuesto tiene el potencial de usarse como fertilizante de lenta liberación al aumentar crecimiento, por lo que podría ser una alternativa para reducir el uso de fertilizantes convencionales y disminuir las pérdidas de nitrógeno en suelo.

Abstract s The profound deficiencies that the country faces in water management policies are reflected in the physicochemical, microbiological and biological contamination of national rivers. The objective of this study was to propose a community water monitoring strategy to improve the management of the Jorco River located in the canton of Acosta. The quality of the water in the upper, middle and lower part of the micro-basin was monitored during the rainy season, using two physicochemical quality indices (ICA): the Dutch and the Calvo-TEC; as well as a biological one: the BMWP-CR. The quality indicators of turbidity, alkalinity, ammonia, ammoniacal nitrogen, nitrates, and fecal coliforms exceeded the permissibility limits in some samples; however, dissolved oxygen showed that there are good levels of oxygen for river recovery. Biochemical oxygen demand was low, indicating low organic load, and macroinvertebrates showed a degraded aquatic ecosystem. The Dutch ICA overestimated the quality of the water with respect to the ICA Calvo-TEC. The latter showed more realistic results because it uses more quality indicators, since it is based on environmental conditions and Costa Rican regulations. The ICA BMWP-CR revealed extreme contamination during the month of greatest rainfall. It was concluded that there is a problem of contamination in the river water whose main causes may be due to the lack of forest cover in the riparian zones, the expansion of coffee cultivation, the discharge of domestic wastewater and livestock activities. Therefore, an action plan was proposed to the municipal council and validated with them, to improve water quality with the participation of different actors in the area.

Resumen Las profundas deficiencias que enfrenta el país en políticas de gestión hídrica se reflejan en la contaminación fisicoquímica, microbiológica y biológica de los ríos nacionales. El objetivo de este estudio fue proponer una estrategia de monitoreo hídrico comunitario para mejorar la gestión del río Jorco ubicado en el cantón de Acosta. Se monitoreó la calidad del agua en la parte alta, media y baja de la microcuenca durante la época lluviosa, utilizando dos índices de calidad (ICA) fisicoquímicos: el Holandés y el Calvo-TEC; así como uno biológico: el BMWP-CR. Los indicadores de calidad de turbiedad, alcalinidad, amoniaco, nitrógeno amoniacal, nitratos, y coliformes fecales superaron los límites de permisibilidad en algunos muestreos; sin embargo, el oxígeno disuelto mostró que existen buenos niveles de oxígeno para la recuperación del río. La demanda bioquímica de oxígeno fue baja, indicando una carga orgánica baja y los macroinvertebrados mostraron un ecosistema acuático degradado. El ICA Holandés sobrevaloró la calidad del agua con respecto al ICA Calvo-TEC. Este último mostró resultados más realistas debido a que utiliza más indicadores de calidad, ya que este parte de las condiciones ambientales y la normativa costarricense. Por su parte, el ICA BMWP-CR reveló una contaminación extrema durante el mes de mayor lluvia. Se concluyó que existe un problema de contaminación en el agua del río cuyas causas principales pueden ser por la falta de cobertura boscosa en las zonas riparias, la expansión del cultivo de café, el vertido de aguas residuales domésticas y las actividades ganaderas. Por lo tanto, se propuso al consejo municipal un plan de acción y validado con ellos, con el fin de mejorar la calidad del agua con participación de diferentes actores de la zona.

Abstract 23. An outbreak of respiratory distress was observed in Holstein cows immediately after consuming a new batch of corn-silage, presumably due to the presence of pneumotoxic gases. Signs were observed in 10% of the cows, and characterized as tachypnea, orthopneic position, cough and notable anxiety a few minutes after offering the silage. No deaths were recorded. Mild leucocytosis was observed in the hemogram. Nutritional analysis and nitrate determination of the corn-silage revealed usual values. Nitrous oxide and methane concentration were evaluated by gas chromatography and nitrogen oxides concentration directly with a portable device, resulting in acceptable values. Although high concentrations of toxic gases could not be evidenced in the air sampled on farm, the clinical signs observed coincide with those reported in cases of exposure to gases formed during corn silage processes. A greater emphasis is required in the evaluation of the corn to be ensiled, given the possible existence of factors that can generate the accumulation of potentially toxic gases for cattle that affect negatively their health and productivity.

Resumen. 27. Se describe un brote de enfermedad respiratoria en vacas Holando Argentino, inmediatamente luego del consumo de un nuevo silaje de planta entera de maíz, presuntamente con presencia de gases neumotóxicos. Se observaron signos en el 10% de las vacas, caracterizados como taquipnea, posición ortopnéica, episodios de tos y ansiedad, unos minutos luego del ofrecimiento del silaje. No se registraron muertes. En el hemograma se observó leucocitosis leve. El análisis de calidad nutricional del alimento y la concentración de nitratos en el silaje de maíz resultó con los valores habituales. Se evaluó la concentración de óxido nitroso y metano en una muestra de silaje de maíz recolectada herméticamente por cromatografía gaseosa, así como la concentración de óxidos de nitrógeno in situ con un instrumento portátil, resultando en valores aceptables. Aunque no se pudieron evidenciar concentraciones de gases elevadas en el aire del silaje muestreado en el tambo, los signos clínicos observados coinciden con los casos reportados de exposición a gases que se forman durante la fermentación del ensilado. Se debería tener en cuenta la evaluación del maíz a ser ensilado, dadas las posibilidades de que se genere la acumulación de gases potencialmente tóxicos para el ganado, que puedan afectar negativamente su salud y productividad.

Resumen Antecedentes: La Planta de tratamiento de aguas residuales (PTAR) Cerro de la Estrella descarga aguas tratadas en diferentes sitios de la Ciudad de México por medio de tubos o vertederos, en donde se desarrollan de manera diferencial, algunas microalgas en función de las condiciones ambientales. Objetivo: Conocer la composición y distribución de la ficoflora asociada a un vertedero proveniente de la PTAR Cerro de la Estrella, sobre un canal de la zona chinampera de Xochimilco, Ciudad de México y su relación con algunas variables físicas y químicas. Métodos: Se establecieron seis puntos de muestreo en un área cercana a un vertedero de agua residual, las muestras de algas se recolectaron con red de arrastre y con botella van Dorn. Se analizaron parámetros físicos y químicos del agua (temperatura, pH, conductividad, nitritos, nitratos y ortofosfatos). El material ficológico se revisó en un microscopio óptico. Se realizó un análisis de regresión lineal para conocer la relación entre riqueza y abundancia de especies versus los parámetros físicos y químicos medidos. Resultados: Se identificó un total de 88 especies pertenecientes a siete Phylum, siendo Bacillariophyta el más diverso con 35 especies, seguido de las Chlorophyta con 26; las Euglenozoa, Cyanobacteria y Miozoa tuvieron 16, 6 y 3 especies respectivamente; mientras que los Phylum Cryptista y Ochrophyta solo presentaron una especie. Los taxa más frecuentes fueron Chlorella sp., Desmodesmus protuberans, Stephanocyclus meneghinianus y Gomphonema sp., encontrándose en los seis puntos muestreados; por su parte los más abundantes fueron Aulacoseira granulata var. angustissima con 1120 cél/mL, S. meneghinianus y Aulacoseira granulata con 960 y 625 cél/mL respectivamente; asimismo Microcystis aeruginosa con 490 cél/mL. Conclusiones: Se observaron 25 nuevos registros para la zona de estudio. Dominaron las especies de los Phylum Bacillariophyta y Chlorophyta. Se registró M. aeruginosa, especie causante de florecimientos algales nocivos, pero pequeñas cantidades. Se observó distribución diferencial de las especies, a pesar de la estabilidad física y química a lo largo de los puntos muestreados.

Abstract Background: The Cerro de la Estrella Wastewater Treatment Plant (PTAR) discharges treated water at different sites in Mexico City through pipes or spillways, where some microalgae develop differentially depending on environmental conditions. Objective: To know the composition and distribution of the phycoflora associated with a landfill from the Cerro de la Estrella WWTP, on a channel in the chinampera area of Xochimilco, Mexico City and its relationship with some physical and chemical variables. Methods: Six sampling points were established in an area close to a wastewater dump, the algae samples were collected with a trawl net and a van Dorn bottle. Physical and chemical parameters of the water (temperature, pH, conductivity, nitrites, nitrates, and orthophosphates) were analyzed. Phycological material was reviewed under an optical microscope. A linear regression analysis was carried out to determine the relationship between richness and abundance of species versus the physical and chemical parameters measured. Results: A total of 88 species belonging to seven Phylum were identified, with Bacillariophyta being the most diverse with 35 species, followed by Chlorophyta with 26; the Euglenozoa, Cyanobacteria and Miozoa had 16, 6 and 3 species respectively; while the Phylum Cryptista and Ochrophyta only presented one species. The most frequent taxa were Chlorella sp., Desmodesmus protuberans, Stephanocyclus meneghinianus and Gomphonema sp., found in the six sampled points; On the other hand, the most abundant were Aulacoseira granulata var. angustissima with 1120 cells/mL, S. meneghinianus and Aulacoseira granulata with 960 and 625 cells/mL respectively; likewise, Microcystis aeruginosa with 490 cells/mL. Conclusions: 25 new records were observed for the study area. Species of the Phylum Bacillariophyta and Chlorophyta dominated. M. aeruginosa, a species that causes harmful algal blooms, was recorded, but in small quantities. Differential distribution of the species was observed, despite the physical and chemical stability throughout the sampled points.

Resumen El área protegida denominada Parque Nacional Río Dulce se encuentra ubicada en el nororiente del caribe de Guatemala. Es administrada por el Consejo Nacional de Áreas Protegidas (CONAP) y regido por un plan maestro. Sin embargo, afronta cada día retos, tales como a) el incremento de desarrollo inmobiliario debido a su belleza escénica, b) el incremento poblacional de las comunidades reconocidas dentro de las diversas zonas del parque y c) vertidos no regularizados de aguas residuales tipos ordinarias y especiales. Ante esta incipiente situación, se hace necesaria la evaluación de la calidad del agua de Río Dulce a través de métodos reconocidos internacionalmente; tal el caso del Índice de Calidad del Agua ICA-NSF, con la finalidad de interpretar los resultados de una manera holística y poder discutirlos en ámbitos académicos, no solo a nivel local, sino internacional. Para ello se georreferenciaron doce estaciones de muestreo en las desembocaduras de los principales tributarios a lo largo del Parque Nacional Río Dulce. Posterior a las colectas de muestras de agua y análisis en laboratorio de los parámetros: coliformes fecales, potencial de hidrógeno, demanda bioquímica de oxígeno, nitratos, fósforo total, temperatura, turbidez, sólidos totales disueltos y oxígeno disuelto, se estimó el ICA-NSF mediante la calculadora en línea del Centro de Investigación del Agua de los Estados Unidos de América. De manera general, considerando la calidad del agua de los afluentes, el ICA-NSF varió entre 71 y 90, lo que se cualifica como una calidad buena. Los parámetros críticos en la disminución del ICA-NSF en las diversas estaciones evaluadas fueron la presencia de coliformes fecales y los sólidos totales disueltos, lo que permite generar lineamientos para el manejo sustentable del Parque Nacional Río Dulce. Se concluye que el agua del Río Dulce no es apta para el consumo humano de forma directa, necesitando de un proceso de potabilización.

Abstract The protected area called Río Dulce National Park is located in the northeastern Caribbean region of Guatemala. It is administered by the National Council of Protected Areas (CONAP) and governed by a master plan. However, it faces challenges every day, such as a) the increase in real estate development due to its scenic beauty, b) the population increase of the recognized communities within the various areas of the park, c) non-regularized discharges of ordinary and special wastewater. Given this incipient situation, it is necessary to evaluate the quality of the water in Río Dulce through internationally recognized methods; such is the case of the ICA-NSF Water Quality Index, with the aim of interpreting the results in a holistic manner and being able to discuss them in academic settings, not only locally, but also internationally. For this, twelve sampling stations were georeferenced at the source of the main tributaries along the Río Dulce National Park. After the collection of water samples and laboratory analysis of the parameters: fecal coliforms, hydrogen potential, biochemical oxygen demand, nitrates, total phosphorus, temperature, turbidity, total dissolved solids and dissolved oxygen, the ICA-NSF was estimated using the online calculator from the Water Research Center of the United States of America. In general, considering the quality of the water of the tributaries, the ICA-NSF varied between 71 and 90, which qualifies as good quality. The critical parameters in the decrease of the ICA-NSF in the various stations evaluated were the presence of fecal coliforms and total dissolved solids, which allows the generation of guidelines for the sustainable management of the Río Dulce National Park. It is concluded that the water of the Río Dulce is not suitable for human consumption directly, requiring a purification process.

Abstract Aim The present study investigated the influence of environmental variables on macrobenthic fauna in the Achenkovil River, Southern Western Ghats, Kerala. The knowledge of aquatic ecosystems in many remote areas is very scanty and no one has yet made an attempt to study the macrobenthic fauna of Achenkovil river. Since, macrobenthos play an important role in the benthic community structure a better knowledge of their ecology and distributional patterns in remote freshwater ecosystems would be of great interest for a better understanding of their functioning. Methods A bimonthly sampling was conducted from February 2019 to January 2020. Water samples for physicochemical analysis were carried to the laboratory in clean polyethylene bottles. The macrobenthic fauna was collected using Van Veen grab (0.025m2). Multivariate statistical technique such as Principal Component Analysis was used to monitor the variation in environmental parameters. The diversity of macrobenthic fauna was studied using Simpson_1-D, Shannon_H, Evenness_e^H/S, and Margalef’s indices. We analyzed the relationship between environmental variables and macrobenthic fauna, using Canonical Correlation Analysis and Pearson correlation. Results A total of 3563 individuals belonging to 9 orders, 32 families, 32 genera, and 32 species were identified. The most dominant order was Ephemeroptera followed by Coleoptera and Trichoptera and the least dominant was Zygoptera. The maximum number of macrobenthic fauna was observed in station 1(S1), (1461 Ind/m2) and the least in station 9 (S9), (37 Ind/m2). Station 1 (S1) is a pristine forest area, so this area is considered the reference site. The macrobenthic fauna in the pristine headwater forests (S1) was much more diverse than in the river mouth (S9) which is a highly impacted region. This region is facing various kinds of anthropogenic stress resulting in pollution and deterioration of water quality. The macrobenthic community structure in the Achenkovil River was significantly associated to the variations in water quality due to various natural as well as anthropogenic stresses. Conclusions It can be concluded that Ephemeroptera, Coleoptera, and Trichoptera were the most dominant groups in the undisturbed habitats in the river during the study period. The predominance of Chironomidae species, especially from the Chironomus genus in the midstream and downstream segments of the river is possibly due to their ability to adapt to various environmental conditions or habitats and their tolerance to the low oxygen content in anoxic conditions of the bottom sediment. The lowest abundance of macrobenthos at all the studied stations was observed at station 9 (S9) during dry seasons. S9 is a highly impacted region, characterized by high temperature, turbidity, TDS, pH, conductivity, nitrate, and phosphate values. For this reason, anthropogenic stress and changing environmental conditions are the main factors affecting the distribution of the macrobenthic fauna of the Achenkovil River basin, Kerala. Ghats Kerala Since functioning 201 2020 bottles 0.025m2. 0025m2 m 0.025m2 . 0 025m2 (0.025m2) parameters Simpson_1D, Simpson1D SimpsonD Simpson_1 D, Simpson D Simpson_1-D ShannonH Shannon H Shannon_H EvennesseHS Evenness e S Evenness_e^H/S Margalefs Margalef s indices correlation 356 orders 3 families genera identified Zygoptera 1S1, 1S1 S1 , 1(S1) 1461 (146 Ind/m2 Indm2 Indm Ind m2 S9, 37 (3 Ind/m2. (S1 site (S9 stresses period sediment seasons temperature turbidity TDS pH conductivity nitrate values reason basin 20 202 0025m 0.025m 025m (0.025m2 1D Simpson_1D Simpson1 Simpson_ 35 1S 1(S1 146 (14 Ind/m ( (S 2 (0.025m 1(S 14 (1

Resumo Objetivo O presente estudo investigou a influência de variáveis ambientais na fauna macrobêntica no rio Achenkovil, Southern Western Ghats, Kerala. O conhecimento dos ecossistemas aquáticos em muitas áreas remotas é muito escasso e ninguém ainda fez uma tentativa de estudar a fauna macrobentônica do rio Achenkovil. Uma vez que os macrobenthos desempenham um papel importante na estrutura da comunidade bentônica, um melhor conhecimento de sua ecologia e padrões de distribuição em ecossistemas remotos de água doce seria de grande interesse para uma melhor compreensão de seu funcionamento. Métodos Foram realizadas coletas bimensais de fevereiro de 2019 a janeiro de 2020. As amostras de água para análises físico-químicas foram levadas ao laboratório em frascos de polietileno limpos. A fauna macrobentônica foi coletada usando garrafa de Van Veen (0,025m2). A técnica estatística multivariada, como a Análise de Componentes Principais, foi utilizada para monitorar a variação dos parâmetros ambientais. A diversidade da fauna macrobêntica foi estudada usando os índices Simpson_1-D, Shannon_H, Evenness_e^H/S e Margalef. Analisou-se a relação entre as variáveis ambientais e a fauna macrobêntica, utilizando a Análise de Correlação Canônica e a Correlação de Pearson. Resultados Foram identificados 3.563 indivíduos pertencentes a 9 ordens, 32 famílias, 32 gêneros e 32 espécies. A ordem mais dominante foi Ephemeroptera seguida por Coleoptera e Trichoptera e a menos dominante foi Zygoptera. O número máximo de fauna macrobentônica foi observado na estação 1(S1), (1461 Ind/m2) e o menor na estação 9 (S9), (37 Ind/m2). A Estação 1 (S1) é uma área de floresta intocada, portanto esta área é considerada o local de referência. A fauna macrobentônica nas florestas virgens da cabeceira (S1) foi muito mais diversa do que na foz do rio (S9), que é uma região altamente impactada. Esta região enfrenta vários tipos de estresse antropogênico, resultando em poluição e deterioração da qualidade da água. A estrutura da comunidade macrobentônica no rio Achenkovil foi significativamente associada às variações na qualidade da água devido a vários estresses naturais e antrópicos Conclusões Pode-se concluir que Ephemeroptera, Coleoptera e Trichoptera foram os grupos mais dominantes nos habitats não perturbados no rio durante o período de estudo. A predominância de espécies de Chironomidae, principalmente do gênero Chironomus nos segmentos médio e jusante do rio, possivelmente se deve à sua capacidade de adaptação a diversas condições ambientais ou habitats e sua tolerância ao baixo teor de oxigênio em condições anóxicas do sedimento de fundo. A menor abundância de macrobentos em todas as estações estudadas foi observada na estação 9 (S9) durante as estações secas. S9 é uma região altamente impactada, caracterizada por alta temperatura, turbidez, TDS, pH, condutividade, nitratos e valores de fosfato. Por esta razão, o estresse antropogênico e a mudança das condições ambientais são os principais fatores que afetam a distribuição da fauna macrobentônica da bacia do rio Achenkovil, Kerala. Ghats Kerala bentônica funcionamento 201 2020 físicoquímicas físico químicas limpos 0,025m2. 0025m2 m 0,025m2 . 0 025m2 (0,025m2) multivariada Principais Simpson_1D, Simpson1D SimpsonD Simpson_1 D, Simpson D Simpson_1-D ShannonH Shannon H Shannon_H EvennesseHS Evenness S Margalef Analisouse Analisou Pearson 3563 3 563 3.56 ordens famílias Zygoptera 1S1, 1S1 S1 , 1(S1) 1461 (146 Ind/m2 Indm2 Indm Ind m2 S9, 37 (3 Ind/m2. (S1 intocada referência impactada Podese Pode Chironomidae fundo (S9 secas temperatura turbidez TDS pH condutividade fosfato razão 20 202 0025m 0,025m 025m (0,025m2 1D Simpson_1D Simpson1 Simpson_ 356 56 3.5 1S 1(S1 146 (14 Ind/m ( (S 2 (0,025m 35 5 3. 1(S 14 (1

Abstract Vegetable crops of the Brassicaceae family have the ability to include the necessary trace element selenium (Se) in the composition of organic compounds such as selenoproteins, in addition, they have important properties for human health based on the content of selenium. In our work, we investigated the effect of non-root processing of vegetating radish plants on the quality of finished products. The research results showed that the selenium content in the product part of plants significantly increased with an increase in the concentration of this element in the working solution. The dry matter content also increased, while its greatest amount was observed at lower concentrations of Se in the working solution. The use of non-root treatment with a selenium-containing solution on vegetative plants led to a significant decrease in the content of ascorbic acid and nitrates, and the decrease in the amount of nitrates in radish root crops was inversely dependent on the concentration of selenium in the working solution. (Se selenoproteins addition work nonroot non products seleniumcontaining containing

Resumo As hortaliças da família Brassicaceae têm a capacidade de incluir o oligoelemento selênio (Se) necessário na composição de compostos orgânicos como as selenoproteínas, além disso, possuem propriedades importantes para a saúde humana com base no teor de selênio. Em nosso trabalho, investigamos o efeito do processamento não radicular de plantas de rabanete vegetantes na qualidade dos produtos acabados. Os resultados da pesquisa mostraram que o teor de selênio na parte do produto das plantas aumentou significativamente com o aumento da concentração desse elemento na solução de trabalho. O teor de matéria seca também elevou, enquanto sua maior quantidade foi observada em menores concentrações de Se na solução de trabalho. O uso de tratamento não radicular com uma solução contendo selênio em plantas vegetativas levou a uma diminuição significativa no teor de ácido ascórbico e nitratos, e a diminuição na quantidade de nitratos nas raízes de rabanete foi inversamente dependente da concentração de selênio na solução de trabalho. (Se selenoproteínas disso trabalho acabados elevou

Resumen Los daños por actividades humanas a los cuerpos de agua dulce tropicales y subtropicales se han incrementado en las últimas décadas. Aquí estudiamos los efectos del uso del suelo sobre la fisicoquímica del agua y en la diversidad de larvas de Odonata en una laguna subtropical. Durante 1 año se midieron variables fisicoquímicas y se colectaron larvas de Odonata en 8 sitios (4 en la zona urbana y 4 en la rural más conservada) con diferente uso de suelo en la periferia de la laguna. Fisicoquímicamente, no se agruparon las muestras de ambas zonas y sitios, la agrupación atendió a la temporalidad. Se colectaron 28 especies, algunas de ellas mostraron una distribución diferencial entre ambas zonas, y entre los 8 sitios y las colectas. La mayor diversidad se registró en la zona rural. El sitio con descargas domésticas fue el más pobre en diversidad y mostró mayores concentraciones de nitratos y amonio. Creemos que el efecto de los usos del suelo sobre la diversidad de odonatos en la laguna es aún incipiente. Se recomienda el desvío y tratamiento de las aguas urbanas y el uso adecuado del suelo para mantener la diversidad de Odonata.

Abstract Impacts caused to freshwater reservoirs by human activities have increased in tropical and subtropical regions in the last decades. We studied the effects of land use on the physicochemical properties of water and their effects on larval Odonata diversity in a subtropical lagoon. During 1 year, physicochemical variables were measured, and Odonata larvae were collected in 8 sites (4 in the urbane zone and 4 in the more conserved rural zone) with different land uses that cover the entire periphery of the lagoon. Physicochemically, no clustering of samples from urban and rural zones or by site was observed, rather clustering reflected temporal patterns. A total of 28 species were found and some of them showed a differential distribution between both zones, and between the 8 sites and samplings. The highest diversity was recorded in the rural zone. The site with domestic waste discharges had the lowest diversity and it showed high concentrations of nitrates and ammonium. We conclude that the effect of land use in this lagoon is still incipient on Odonata diversity. The diversion and treatment of urban waters and proper land management are recommended to ensure the maintenance of Odonata diversity.

ABSTRACT The ecological condition is a parameter that allows us to diagnose the structure and functionality of rivers. The Margaritas River basin, located in the municipality of Pijijiapan, Chiapas, Mexico, is an important source of water recharge and supply. In order to evaluate the ecological condition present at three altitudinal gradients of the Margaritas River, a visual evaluation of the physical habitat was performed following Barbour’s protocol and some physical-chemical parameters were determined (depth, dissolved oxygen, electrical conductivity, temperature, salinity and hydrogen potential). Ammonium, nitrite, nitrate and phosphate ions were also measured at the three study sites. Three replicates were carried out and an analysis of variance and comparison of means by Tukey-kramer (p ≥ 0.05) was applied. The results showed a suboptimal (Margaritas 1 and 2 sites) and marginal (Río Ramón site) habitat condition. Physicochemical parameters presented significant differences for site-specific electrical conductivity (F2,6 = 68.77 p ≤ 0.0001), electrical conductivity at 25 ºC (F2,6 = 59.67 p = 0.0001) and water temperature (F2,6 = 160.66, p ≤ 0.0001), where the highest values correspond to site Margaritas 2. The amount of nitrates (6.83 ± 0.55 mg/L) and nitrites (3.67 ± 1.15 mg/L) at site Margaritas 2 were the highest values obtained. Finally, phosphate ions presented their highest values at the Río Ramón site (0.12 ± 0.05 mg/L). The results obtained provide a current perspective on the state and condition of the Margaritas River, and it is necessary to implement appropriate management strategies for each study area.

RESUMEN La condición ecológica es un parámetro que permite diagnosticar la estructura y funcionalidad de los ríos. La cuenca del Río Margaritas, localizada en el municipio de Pijijiapan, Chiapas, México es una fuente importante de recarga y provisión hídrica. Con el objetivo de evaluar la condición ecológica presente en un gradiente altitudinal del Río Margaritas, se realizó la evaluación visual del hábitat físico a través del protocolo de Barbour y se determinaron los parámetros fisicoquímicos (profundidad, oxígeno disuelto, conductividad eléctrica, temperatura, salinidad y potencial de Hidrógeno). También se cuantificaron los iones de amonio, nitritos, nitratos y fosfatos en tres sitios de estudio. Se realizaron tres repeticiones y se aplicó un análisis de varianza y comparación de medias por Tukey-kramer (p ≥ 0.05). Los resultados mostraron una condición de hábitat sub óptima (sitios Margaritas 1 y 2) y marginal (sitio Río Ramón). Los parámetros fisicoquímicos presentaron diferencias significativas para la conductividad eléctrica específica en el sitio (F2,6 = 68.77 p ≤ 0.0001), conductividad eléctrica a 25 ºC (F2,6 = 59.67 p = 0.0001) y temperatura del agua (F2,6 = 160.66, p ≤ 0.0001), donde los valores más altos fueron los del sitio Margaritas 2. La concentración de nitratos (6.83 ± 0.55 mg/L) y nitritos (3.67 ± 1.15 mg/L) obtenidos en el sitio Margaritas 2 fueron los valores más altos. Finalmente, los iones de fosfato presentaron los valores más altos en el sitio Río Ramón (0.12 ± 0.05 mg/L). Los resultados obtenidos brindan una perspectiva actual sobre el estado y condición del Río Margaritas, siendo necesario implementar estrategias de gestión propicias para cada zona de estudio.

Abstract Due to the accelerated growth of the world population, the need for food has increased. Due to the differentiated climatic factors that Ecuador has, the usage of pesticides and fertilizers has increased at an alarming rate, in search of increasing the productivity of crops, which results in an accumulation of residues in food and soil. In this study, the search for concentrations of metals and ions from fertilizers in four high-consumption products will be limited to INIAP Cecilia and Chaucha Amarilla potatoes, Kidney Tomato and Paiteña Onion found in markets and supermarkets. The metals were determined by using inductively coupled plasma spectrometry with a mass spectrometer (ICP-MS). For ions, through a UV-visible spectrophotometer. The values found were within the norm. Differences were found between the metal content of the potato between peel and pulp where the latter will appear at the highest concentrations. Multivariate statistics showed that the samples are grouped by the planting site and not the type of sample, which shows the importance of the soil and the cultivation process. The generation of a classification model for fed products with the analyzed parameters is discussed.

Resumen Debido al crecimiento acelerado de la población, el requerimiento de alimentos se ha incrementado. A esta demanda se suman los factores climáticos diferenciados que tiene Ecuador, los cuales inciden en que los agricultores utilicen pesticidas y fertilizantes de forma indiscriminada para incrementar la productividad de los cultivos. El resultado de esta práctica es una acumulación de residuos tanto en los alimentos como en el suelo. En este estudio se determinó las concentraciones de metales e iones provenientes de los fertilizantes en cuatro productos de alto consumo: papa INIAP Cecilia, papa chaucha amarilla, tomate riñón y cebolla paiteña encontrados en los mercados y supermercados. Los metales fueron determinados por espectrometría de plasma acoplado inductivamente con espectrómetro de masas (ICP-MS) y los iones a través de un espectrofotómetro UV-visible. Los valores encontrados estuvieron dentro de la norma. Se detectó diferencias entre la concentración de metales de la papa entre cáscara y pulpa donde esta última mantenía las mayores concentraciones. La estadística multivariada permitió evidenciar que las muestras se agrupan por el sitio de siembra y no por el tipo de muestra, lo que revela la importancia del suelo y el proceso de cultivo. Se obtuvo un modelo de clasificación de productos con base en los parámetros analizados.

Resumen El objetivo de esta investigación fue describir espacial y temporalmente las concentraciones de nitratos en correlación con las actividades antropogénicas que rodean el río Sierpe que atraviesa el Humedal Nacional Térraba-Sierpe (HNTS). Aunque protegido territorialmente por la legislación costarricense, este humedal está rodeado por una intensa actividad agrícola. En el 2018 se realizó un monitoreo mensual de pH, nitratos y oxígeno disuelto (OD) en catorce puntos del río. Se obtuvo una línea base alrededor de 5 mg NO3 -/L en períodos sin actividades agrícolas y picos hasta de 20 mg NO3 -/L después de las actividades de fertilización. Correspondientemente se observó disminución de OD y pH en los días de alta actividad agrícola. En los meses posteriores a la fertilización, los colaboradores del programa de manejo y vigilancia del HNTS observan un crecimiento acelerado de plantas acuáticas y un deterioro general en la reproducción del manglar. Sin embargo, cuando se observa una alta concentración de nitratos en áreas agrícolas, también se observa su declive en la dirección del flujo del río hasta su desembocadura. Este hecho muestra la función aún activa del humedal y su importancia en el procesamiento de nitratos. Se recomienda regular las actividades no solo en el límite territorial sino también en los límites del sistema hídrico circundante al HNTS para proteger esta función ecosistémica.

Resumo Esta pesquisa teve como objetivo descrever espacial e temporariamente as concentrações de nitrato em correlação com as atividades antropogênicas que cercam o rio Sierpe. Este rio atravessa a Zona Úmida Nacional Térraba-Sierpe (HNTS) que, embora territorialmente protegida pela legislação costarriquenha, é cercada por intensa atividade agrícola. Em 2018, foi realizado um monitoramento mensal de pH, nitratos e oxigênio dissolvido em catorze pontos do rio, onde foi obtida uma linha de base em torno de 5 mg NO3 -/L em períodos sem atividades agrícolas e picos de até 20 mg NO3 -/L após eventos de fertilização. Correspondentemente, observou-se a diminuição do oxigênio dissolvido e do pH nos dias de alta atividade agrícola. Nos meses seguintes à fertilização, os colaboradores do programa de gestão e vigilância do HNTS observam um crescimento acelerado de plantas aquáticas e uma deterioração geral na reprodução de manguezais. No entanto, a concentração de nitratos diminui sistematicamente na direção do fluxo do rio até chegar à foz, o que mostra a função ainda ativa da zona úmida e sua importância no processamento de nitratos. A fim de proteger essa função ecossistêmica, recomenda-se a necessidade de regulação das atividades, não apenas dentro do limite territorial, mas também dos limites do sistema de água em torno do HNTS.

Abstract This research aimed to describe, spatially and temporally, the concentrations of nitrates in correlation with anthropogenic activities surrounding the Sierpe River that crosses the National Térraba-Sierpe Wetland (HNTS). Although territorially protected by Costa Rican legislation, this wetland is surrounded by intense agricultural activity. In 2018, monthly monitoring of pH, nitrates, and dissolved oxygen was carried out in fourteen points of the river. A baseline around 5 mg NO3 - / L was obtained in periods without agricultural activities and peaks up to 20 mg NO3 - / L after fertilization activities. Correspondingly, a decrease in dissolved oxygen and pH was observed on days of high agricultural activity. In the months following fertilization, accelerated growth of aquatic plants and a general deterioration in mangrove reproduction were observed by collaborators of the HNTS management and surveillance program. Nevertheless, when high nitrates concentration in agricultural areas are observed, their decline is also observed in the direction of the river's flow until it reaches its mouth. This facts shows the still active function of the wetland and its importance in the processing of nitrates. To regulate activities not only in the territorial limit but also in the limits of the water system surrounding the HNTS is recommended to protect this ecosystem function.